Effects of High Intensity Interval Training on Increasing Explosive Power, Speed, and Agility

NASA Astrophysics Data System (ADS)

Fajrin, F.; Kusnanik, N. W.; Wijono

2018-01-01

High Intensity Interval Training (HIIT) is a type of exercise that combines high-intensity exercise and low intensity exercise in a certain time interval. This type of training is very effective and efficient to improve the physical components. The process of improving athletes achievement related to how the process of improving the physical components, so the selection of a good practice method will be very helpful. This study aims to analyze how is the effects of HIIT on increasing explosive power, speed, and agility. This type of research is quantitative with quasi-experimental methods. The design of this study used the Matching-Only Design, with data analysis using the t-test (paired sample t-test). After being given the treatment for six weeks, the results showed there are significant increasing in explosive power, speed, and agility. HIIT in this study used a form of exercise plyometric as high-intensity exercise and jogging as mild or moderate intensity exercise. Increase was due to the improvement of neuromuscular characteristics that affect the increase in muscle strength and performance. From the data analysis, researchers concluded that, Exercises of High Intensity Interval Training significantly effect on the increase in Power Limbs, speed, and agility.

Oscillation of tissue oxygen index in non-exercising muscle during exercise.

PubMed

Yano, T; Afroundeh, R; Shirakawa, K; Lian, C-S; Shibata, K; Xiao, Z; Yunoki, T

2015-09-01

The purpose of the present study was to examine how oscillation of tissue oxygen index (TOI) in non-exercising exercise is affected during high-intensity and low-intensity exercises. Three exercises were performed with exercise intensities of 30% and 70% peak oxygen uptake (Vo(2)peak) for 12 min and with exercise intensity of 70% Vo(2)peak for 30 s. TOI in non-exercising muscle (biceps brachii) during the exercises for 12 min was determined by nearinfrared spectroscopy. TOI in the non-exercising muscle during the exercises was analyzed by fast Fourier transform (FFT) to obtain power spectra density (PSD). The frequency at which maximal PSD appeared (Fmax) during the exercise with 70% Vo(2)peak for 12 min (0.00477 ± 0.00172 Hz) was significantly lower than that during the exercise with 30% Vo2peak for 12 min (0.00781 ± 0.00338 Hz). There were significant differences in blood pH and blood lactate between the exercise with 70% Vo(2)peak and the exercise with 30% Vo(2)peak. It is concluded that TOI in nonexercising muscle oscillates during low-intensity exercise as well as during high-intensity exercise and that the difference in Fmax between the two exercises is associated with the difference in increase in blood lactate derived from the exercise.

Attentional bias to emotional stimuli is altered during moderate- but not high-intensity exercise.

PubMed

Tian, Qu; Smith, J Carson

2011-12-01

Little is known regarding how attention to emotional stimuli is affected during simultaneously performed exercise. Attentional biases to emotional face stimuli were assessed in 34 college students (17 women) using the dot-probe task during counterbalanced conditions of moderate- (heart rate at 45% peak oxygen consumption) and high-intensity exercise (heart rate at 80% peak oxygen consumption) compared with seated rest. The dot-probe task consisted of 1 emotional face (pleasant or unpleasant) paired with a neutral face for 1,000 ms; 256 trials (128 trials for each valence) were presented during each condition. Each condition lasted approximately 10 min. Participants were instructed to perform each trial of the dot-probe task as quickly and accurately as possible during the exercise and rest conditions. During moderate-intensity exercise, participants exhibited significantly greater attentional bias scores to pleasant compared with unpleasant faces (p < .01), whereas attentional bias scores to emotional faces did not differ at rest or during high-intensity exercise (p > .05). In addition, the attentional bias to unpleasant faces was significantly reduced during moderate-intensity exercise compared with that during rest (p < .05). These results provide behavioral evidence that during exercise at a moderate intensity, there is a shift in attention allocation toward pleasant emotional stimuli and away from unpleasant emotional stimuli. Future work is needed to determine whether acute exercise may be an effective treatment approach to reduce negative bias or enhance positive bias in individuals diagnosed with mood or anxiety disorders, or whether attentional bias during exercise predicts adherence to exercise. (c) 2011 APA, all rights reserved.

High-intensity exercise training for the prevention of type 2 diabetes mellitus.

PubMed

Rynders, Corey A; Weltman, Arthur

2014-02-01

Aerobic exercise training and diet are recommended for the primary prevention of type 2 diabetes mellitus and cardiovascular disease. The American Diabetes Association (ADA) recommends that adults with prediabetes engage in ≥ 150 minutes per week of moderate activity and target a 7% weight loss. However, traditional moderate-intensity (MI) exercise training programs are often difficult to sustain for prediabetic adults; a commonly cited barrier to physical activity in this population is the "lack of time" to exercise. When matched for total energy expenditure, high-intensity (HI) exercise training has a lower overall time commitment compared with traditional low-intensity (LI) or MI exercise training. Several recent studies comparing HI exercise training with LI and MI exercise training reported that HI exercise training improves skeletal muscle metabolic control and cardiovascular function in a comparable and/or superior way relative to LI and MI exercise training. Although patients can accrue all exercise benefits by performing LI or MI activities such as walking, HI activities represent a time-efficient alternative to meeting physical activity guidelines. High-intensity exercise training is a potent tool for improving cardiometabolic risk for prediabetic patients with limited time and may be prescribed when appropriate.

Role of beta-alanine supplementation on muscle carnosine and exercise performance.

PubMed

Artioli, Guilherme Giannini; Gualano, Bruno; Smith, Abbie; Stout, Jeffrey; Lancha, Antonio Herbert

2010-06-01

In this narrative review, we present and discuss the current knowledge available on carnosine and beta-alanine metabolism as well as the effects of beta-alanine supplementation on exercise performance. Intramuscular acidosis has been attributed to be one of the main causes of fatigue during intense exercise. Carnosine has been shown to play a significant role in muscle pH regulation. Carnosine is synthesized in skeletal muscle from the amino acids l-histidine and beta-alanine. The rate-limiting factor of carnosine synthesis is beta-alanine availability. Supplementation with beta-alanine has been shown to increase muscle carnosine content and therefore total muscle buffer capacity, with the potential to elicit improvements in physical performance during high-intensity exercise. Studies on beta-alanine supplementation and exercise performance have demonstrated improvements in performance during multiple bouts of high-intensity exercise and in single bouts of exercise lasting more than 60 s. Similarly, beta-alanine supplementation has been shown to delay the onset of neuromuscular fatigue. Although beta-alanine does not improve maximal strength or VO2max, some aspects of endurance performance, such as anaerobic threshold and time to exhaustion, can be enhanced. Symptoms of paresthesia may be observed if a single dose higher than 800 mg is ingested. The symptoms, however, are transient and related to the increase in plasma concentration. They can be prevented by using controlled release capsules and smaller dosing strategies. No important side effect was related to the use of this amino acid so far. In conclusion, beta-alanine supplementation seems to be a safe nutritional strategy capable of improving high-intensity anaerobic performance.

Effects of Locomotor Exercise Intensity on Gait Performance in Individuals With Incomplete Spinal Cord Injury

PubMed Central

Leech, Kristan A.; Kinnaird, Catherine R.; Holleran, Carey L.; Kahn, Jennifer

2016-01-01

Background High-intensity stepping practice may be a critical component to improve gait following motor incomplete spinal cord injury (iSCI). However, such practice is discouraged by traditional theories of rehabilitation that suggest high-intensity locomotor exercise degrades gait performance. Accordingly, such training is thought to reinforce abnormal movement patterns, although evidence to support this notion is limited. Objective The purposes of this study were: (1) to evaluate the effects of short-term manipulations in locomotor intensity on gait performance in people with iSCI and (2) to evaluate potential detrimental effects of high-intensity locomotor training on walking performance. Design A single-day, repeated-measures, pretraining-posttraining study design was used. Methods Nineteen individuals with chronic iSCI performed a graded-intensity locomotor exercise task with simultaneous collection of lower extremity kinematic and electromyographic data. Measures of interest were compared across intensity levels of 33%, 67%, and 100% of peak gait speed. A subset of 9 individuals participated in 12 weeks of high-intensity locomotor training. Similar measurements were collected and compared between pretraining and posttraining evaluations. Results The results indicate that short-term increases in intensity led to significant improvements in muscle activity, spatiotemporal metrics, and joint excursions, with selected improvements in measures of locomotor coordination. High-intensity locomotor training led to significant increases in peak gait speed (0.64–0.80 m/s), and spatiotemporal and kinematic metrics indicate a trend for improved coordination. Limitations Measures of gait performance were assessed during treadmill ambulation and not compared with a control group. Generalizability of these results to overground ambulation is unknown. Conclusions High-intensity locomotor exercise and training does not degrade, but rather improves, locomotor function and quality in individuals with iSCI, which contrasts with traditional theories of motor dysfunction following neurologic injury. PMID:27313241

High Intensity Resistive and Rowing Exercise Countermeasures Do Not Prevent Orthostatic Intolerance Following 70 Days of Bed Rest

NASA Technical Reports Server (NTRS)

Lee, Stuart M. C.; Stenger, Michael B.; Laurie, Steven S.; Ploutz-Snyder, Lori L.; Platts, Steven H.

2015-01-01

More than 60% of US astronauts participating in Mir and early International Space Station missions (greater than 5 months) were unable to complete a 10-min 80 deg head-up tilt test on landing day. This high incidence of post-spaceflight orthostatic intolerance may be related to limitations of the inflight exercise hardware that prevented high intensity training. PURPOSE: This study sought to determine if a countermeasure program that included intense lower-body resistive and rowing exercises designed to prevent cardiovascular and musculoskeletal deconditioning during 70 days of 6 deg head-down tilt bed rest (BR), a spaceflight analog, also would protect against post- BR orthostatic intolerance. METHODS: Sixteen males participated in this study and performed no exercise (Control, n=10) or performed an intense supine exercise protocol with resistive and aerobic components (Exercise, n=6). On 3 days/week, exercise subjects performed lower body resistive exercise and a 30-min continuous bout of rowing (greater than or equal to 75% max heart rate). On 3 other days/week, subjects performed only high-intensity, interval-style rowing. Orthostatic intolerance was assessed using a 15-min 80 deg head-up tilt test performed 2 days (BR-2) before and on the last day of BR (BR70). Plasma volume was measured using a carbon monoxide rebreathing technique on BR-3 and before rising on the first recovery day (BR+0). RESULTS: Following 70 days of BR, tilt tolerance time decreased significantly in both the Control (BR-2: 15.0 +/- 0.0, BR70: 9.9 +/- 4.6 min, mean +/- SD) and Exercise (BR-2: 12.2 +/- 4.7, BR70: 4.9 +/- 1.9 min) subjects, but the decreased tilt tolerance time was not different between groups (Control: -34 +/- 31, Exercise: -56 +/- 16%). Plasma volume also decreased (Control: -0.56 +/- 0.40, Exercise: -0.48 +/- 0.33 L) from pre to post-BR, with no differences between groups (Control: -18 +/- 11%, Exerciser: -15 +/-1 0%). CONCLUSIONS: These findings confirm previous reports in shorter BR studies that the performance of an exercise countermeasure protocol by itself during BR does not prevent orthostatic intolerance or plasma volume loss. This suggests that protection against orthostatic intolerance in astronauts following long-duration spaceflight will require an additional intervention, such as periodic orthostatic stress, fluid repletion, and/or lower-body compression garments.

Muscle metabolic responses during high-intensity intermittent exercise measured by 31P-MRS: relationship to the critical power concept

PubMed Central

Chidnok, Weerapong; DiMenna, Fred J.; Fulford, Jonathan; Bailey, Stephen J.; Skiba, Philip F.; Vanhatalo, Anni

2013-01-01

We investigated the responses of intramuscular phosphate-linked metabolites and pH (as assessed by 31P-MRS) during intermittent high-intensity exercise protocols performed with different recovery-interval durations. Following estimation of the parameters of the power-duration relationship, i.e., the critical power (CP) and curvature constant (W′), for severe-intensity constant-power exercise, nine male subjects completed three intermittent exercise protocols to exhaustion where periods of high-intensity constant-power exercise (60 s) were separated by different durations of passive recovery (18 s, 30 s and 48 s). The tolerable duration of exercise was 304 ± 68 s, 516 ± 142 s, and 847 ± 240 s for the 18-s, 30-s, and 48-s recovery protocols, respectively (P < 0.05). The work done >CP (W>CP) was significantly greater for all intermittent protocols compared with the subjects' W′, and this difference became progressively greater as recovery-interval duration was increased. The restoration of intramuscular phosphocreatine concentration during recovery was greatest, intermediate, and least for 48 s, 30 s, and 18 s of recovery, respectively (P < 0.05). The W>CP in excess of W′ increased with greater durations of recovery, and this was correlated with the mean magnitude of muscle phosphocreatine reconstitution between work intervals (r = 0.61; P < 0.01). The results of this study show that during intermittent high-intensity exercise, recovery intervals allow intramuscular homeostasis to be restored, with the degree of restoration being related to the duration of the recovery interval. Consequently, and consistent with the intermittent CP model, the ability to perform W>CP during intermittent high-intensity exercise and, therefore, exercise tolerance, increases when recovery-interval duration is extended. PMID:24068048

Effect of exercise intensity and mode on acute appetite control in men and women.

PubMed

Panissa, Valéria Leme Gonçalves; Julio, Ursula Ferreira; Hardt, Felipe; Kurashima, Carolina; Lira, Fábio Santos; Takito, Monica Yuri; Franchini, Emerson

2016-07-07

The aim of this study was to compare the effects of exercise intensity on appetite control: relative energy intake (energy intake minus the energy expenditure of exercise; REI), hunger scores, and appetite-regulating hormones in men and women. Eleven men and 9 women were submitted to 4 experimental sessions: high-intensity intermittent all-out exercise (HIIE-A) for 60 × 8 s interspersed by 12 s of passive recovery; high-intensity intermittent exercise (HIIE) at 100% of maximal load attained in incremental test; steady-state exercise at 60% of maximal load, matched by work done; and a control session. Exercise was performed 1.5 h after a standardized breakfast, and an ad libitum lunch was offered 4 h after breakfast. Blood concentration of insulin, cortisol, acylated ghrelin, peptideYY 3-36 , glucose, and hunger scores were measured when fasting, and at 1.5, 2, 3.25, and 4 h of experiment. REI was lower in all exercises than in the control, without differences between exercises and sex showing no compensation in energy intake because of any exercise; the hunger scores were lower only in the exercises performed at higher intensity (HIIE and HIIE-A) compared with the control. The area under the curve of acylated ghrelin was lower in the HIIE-A when compared with the control. PeptideYY 3-36 was higher in men than women and cortisol higher in women than men independently of the condition. Although high-intensity exercises promoted a little more pronounced effects in the direction of suppressing the appetite, no differences were observed in REI, demonstrating that these modifications were not sufficient to affect energy intake.

A Probability Model of Decompression Sickness at 4.3 Psia after Exercise Prebreathe

NASA Technical Reports Server (NTRS)

Conkin, Johnny; Gernhardt, Michael L.; Powell, Michael R.; Pollock, Neal

2004-01-01

Exercise PB can reduce the risk of decompression sickness on ascent to 4.3 psia when performed at the proper intensity and duration. Data are from seven tests. PB times ranged from 90 to 150 min. High intensity, short duration dual-cycle ergometry was done during the PB. This was done alone, or combined with intermittent low intensity exercise or periods of rest for the remaining PB. Nonambulating men and women performed light exercise from a semi-recumbent position at 4.3 psia for four hrs. The Research Model with age tested the probability that DCS increases with advancing age. The NASA Model with gender hypothesized that the probability of DCS increases if gender is female. Accounting for exercise and rest during PB with a variable half-time compartment for computed tissue N2 pressure advances our probability modeling of hypobaric DCS. Both models show that a small increase in exercise intensity during PB reduces the risk of DCS, and a larger increase in exercise intensity dramatically reduces risk. These models support the hypothesis that aerobic fitness is an important consideration for the risk of hypobaric DCS when exercise is performed during the PB.

Acute Exercise and Motor Memory Consolidation: The Role of Exercise Timing

PubMed Central

Christiansen, Lasse; Roig, Marc

2016-01-01

High intensity aerobic exercise amplifies offline gains in procedural memory acquired during motor practice. This effect seems to be evident when exercise is placed immediately after acquisition, during the first stages of memory consolidation, but the importance of temporal proximity of the exercise bout used to stimulate improvements in procedural memory is unknown. The effects of three different temporal placements of high intensity exercise were investigated following visuomotor skill acquisition on the retention of motor memory in 48 young (24.0 ± 2.5 yrs), healthy male subjects randomly assigned to one of four groups either performing a high intensity (90% Maximal Power Output) exercise bout at 20 min (EX90), 1 h (EX90+1), 2 h (EX90+2) after acquisition or rested (CON). Retention tests were performed at 1 d (R1) and 7 d (R7). At R1 changes in performance scores after acquisition were greater for EX90 than CON (p < 0.001) and EX90+2 (p = 0.001). At R7 changes in performance scores for EX90, EX90+1, and EX90+2 were higher than CON (p < 0.001, p = 0.008, and p = 0.008, resp.). Changes for EX90 at R7 were greater than EX90+2 (p = 0.049). Exercise-induced improvements in procedural memory diminish as the temporal proximity of exercise from acquisition is increased. Timing of exercise following motor practice is important for motor memory consolidation. PMID:27446616

Perceptual Responses to High- and Moderate-Intensity Interval Exercise in Adolescents.

PubMed

Malik, Adam A; Williams, Craig A; Weston, Kathryn L; Barker, Alan R

2018-05-01

Continuous high-intensity exercise is proposed to evoke unpleasant sensations as predicted by the dual-mode theory and may negatively impact on future exercise adherence. Previous studies support unpleasant sensations in affective responses during continuous high-intensity exercise, but the affect experience during high-intensity interval exercise (HIIE) involving brief bursts of high-intensity exercise separated by low-intensity activity is poorly understood in adolescents. We examined the acute affective, enjoyment, and perceived exertion responses to HIIE compared with moderate-intensity interval exercise (MIIE) in adolescents. Thirteen adolescent boys (mean ± SD: age, 14.0 ± 0.5 yr) performed two counterbalanced exercise conditions: 1) HIIE: 8 × 1-min work intervals at 90% maximal aerobic speed; and 2) MIIE: between 9 and 12 × 1-min work intervals at 90% ventilatory threshold where the number of intervals performed were distance-matched to HIIE. HIIE and MIIE work intervals were interspersed with 75 s active recovery at 4 km·h. Affect, enjoyment, and RPE were recorded before, during, and after exercise. Affect responses declined in both conditions but the fall was greater in HIIE than MIIE (P < 0.025, effect size [ES], 0.64 to 0.81). Affect remained positive at the end-work interval for both conditions (MIIE, 2.62 ± 1.50; HIIE, 1.15 ± 2.08 on feeling scale). No enjoyment differences were evident during HIIE and MIIE (P = 0.32), but HIIE elicited greater postexercise enjoyment compared with MIIE (P = 0.01, ES = 0.47). RPE was significantly higher during HIIE than MIIE across all work intervals (all P < 0.03, ES > 0.64). Despite elevated RPE, HIIE did not elicit prominent unpleasant feelings as predicted by the dual-mode theory and was associated with greater postexercise enjoyment responses than MIIE. This study demonstrates the feasibility of the application of HIIE as an alternative form of physical activity in adolescents.

Effects of active recovery during interval training on plasma catecholamines and insulin.

PubMed

Nalbandian, Harutiun M; Radak, Zsolt; Takeda, Masaki

2018-06-01

BACKGROUNDː Active recovery has been used as a method to accelerate the recovery during intense exercise. It also has been shown to improve performance in subsequent exercises, but little is known about its acute effects on the hormonal and metabolic profile. The aim of this research was to study the effects of active recovery on plasma catecholamines and plasma insulin during a high-intensity interval exercise. METHODSː Seven subjects performed two high-intensity interval training protocols which consisted of three 30-second high-intensity bouts (constant intensity), separated by a recovery of 4 minutes. The recovery was either active recovery or passive recovery. During the main test blood samples were collected and plasma insulin, plasma catecholamines and blood lactate were determined. Furthermore, respiratory gasses were also measured. RESULTSː Plasma insulin and blood lactate were significantly higher in the passive recovery trial, while plasma adrenaline was higher in the active recovery. Additionally, VO2 and VCO2 were significantly more increased during the active recovery trials. CONCLUSIONSː These results suggest that active recovery affects the hormonal and metabolic responses to high-intensity interval exercise. Active recovery produces a hormonal environment which may favor lipolysis and oxidative metabolism, while passive recovery may be favoring glycolysis.

Physiological parameter values in greyhounds before and after high-intensity exercise.

PubMed

Pellegrino, Francisco Javier; Risso, Analía; Vaquero, Pablo G; Corrada, Yanina A

2018-01-01

Dog sports competitions have greatly expanded. The availability of reference values for each type of activity could help assess fitness accurately. Heart rate (HR), blood lactate (BL) and rectal temperature (RT) are relevant physiological parameters to determine the dogs response to effort. Previous studies in greyhounds have reported the effect of high-intensity exercise on many physiological parameters immediately after completing different racing distances and recovery times. However, there are no studies concerning physiological changes over shorter racing distances. We therefore assessed the effect of sprint exercise on HR, BL and RT in nine greyhounds performing sprint exercise over a 100-m distance chasing a lure. After the exercise, dogs underwent a passive 10-min recovery phase. Before the exercise, immediately after it and at 5 and 10 min during recovery, HR and RT were assessed and blood samples were collected for BL determination. HR, BL and RT values increased significantly after the exercise (P<0.01). Whereas HR returned to pre-exercise values at 10 min during the recovery phase (P>0.1), BL concentration and RT remained increased (P<0.01). The abrupt increase in HR, BL and RT values observed immediately after the exercise indicates the high intensity of the effort performed. Similarly, BL concentration after the exercise exceeded the 4 mmol/L lactate threshold, suggesting a predominant anaerobic metabolism during effort. Although HR returned to pre-exercise values 10 min after the exercise, a more extensive recovery phase would be necessary for a total return to resting values, particularly for BL and RT. In greyhounds subjected to high-intensity exercise, HR, BL and RT were reliable physiological parameters to accurately assess the physiological response to effort. The use of sprint exercises over short racing distances could be useful for appropriately monitoring fitness in sporting dogs.

Conducting an acute intense interval exercise session during the Ramadan fasting month: what is the optimal time of the day?

PubMed

Aziz, Abdul Rashid; Chia, Michael Yong Hwa; Low, Chee Yong; Slater, Gary John; Png, Weileen; Teh, Kong Chuan

2012-10-01

This study examines the effects of Ramadan fasting on performance during an intense exercise session performed at three different times of the day, i.e., 08:00, 18:00, and 21:00 h. The purpose was to determine the optimal time of the day to perform an acute high-intensity interval exercise during the Ramadan fasting month. After familiarization, nine trained athletes performed six 30-s Wingate anaerobic test (WAnT) cycle bouts followed by a time-to-exhaustion (T(exh)) cycle on six separate randomized and counterbalanced occasions. The three time-of-day nonfasting (control, CON) exercise sessions were performed before the Ramadan month, and the three corresponding time-of-day Ramadan fasting (RAM) exercise sessions were performed during the Ramadan month. Note that the 21:00 h session during Ramadan month was conducted in the nonfasted state after the breaking of the day's fast. Total work (TW) completed during the six WAnT bouts was significantly lower during RAM compared to CON for the 08:00 and 18:00 h (p < .017; effect size [d] = .55 [small] and .39 [small], respectively) sessions, but not for the 21:00 h (p = .03, d = .18 [trivial]) session. The T(exh) cycle duration was significantly shorter during RAM than CON in the 18:00 (p < .017, d = .93 [moderate]) session, but not in the 08:00 (p = .03, d = .57 [small]) and 21:00 h (p = .96, d = .02 [trivial]) sessions. In conclusion, Ramadan fasting had a small to moderate, negative impact on quality of performance during an acute high-intensity exercise session, particularly during the period of the daytime fast. The optimal time to conduct an acute high-intensity exercise session during the Ramadan fasting month is in the evening, after the breaking of the day's fast.

An acute bout of localized resistance exercise can rapidly improve inhibitory control

PubMed Central

Tsukamoto, Hayato; Suga, Tadashi; Takenaka, Saki; Takeuchi, Tatsuya; Tanaka, Daichi; Hamaoka, Takafumi; Hashimoto, Takeshi; Isaka, Tadao

2017-01-01

The positive effect of acute resistance exercise on executive function, such as inhibitory control (IC), is poorly understood. Several previous studies have demonstrated this effect using whole-body resistance exercise. However, it remains unclear whether localized resistance exercise performed using only limited muscle groups could also acutely improve IC. Thus, the present study examined the effect of an acute bout of localized resistance exercise on IC. Twelve healthy men performed a color-word Stroop task (CWST) before and immediately after the experimental conditions, which consisted of 2 resistance exercises and a resting control (CON). Bilateral knee extension was used to create 2 resistance exercise conditions: light-intensity resistance exercise (LRE) and high-intensity resistance exercise (HRE) conditions, which were 40% and 80% of one-repetition maximum, respectively. The resistance exercise session was programmed for 6 sets with 10 repetitions per set. The CWST-measured IC was significantly improved immediately after both LRE and HRE, but it did not improve immediately after CON. However, the improved IC was significantly greater in HRE than in LRE. The present findings showed that IC could be rapidly improved by an acute bout of localized resistance exercise, especially with high-intensity. Therefore, we suggest that in addition to whole-body resistance exercise, localized resistance exercise performed using limited muscle groups may be sufficient for improving IC. PMID:28877232

Continuous low- to moderate-intensity exercise training is as effective as moderate- to high-intensity exercise training at lowering blood HbA(1c) in obese type 2 diabetes patients.

PubMed

Hansen, D; Dendale, P; Jonkers, R A M; Beelen, M; Manders, R J F; Corluy, L; Mullens, A; Berger, J; Meeusen, R; van Loon, L J C

2009-09-01

Exercise represents an effective interventional strategy to improve glycaemic control in type 2 diabetes patients. However, the impact of exercise intensity on the benefits of exercise training remains to be established. In the present study, we compared the clinical benefits of 6 months of continuous low- to moderate-intensity exercise training with those of continuous moderate- to high-intensity exercise training, matched for energy expenditure, in obese type 2 diabetes patients. Fifty male obese type 2 diabetes patients (age 59 +/- 8 years, BMI 32 +/- 4 kg/m(2)) participated in a 6 month continuous endurance-type exercise training programme. All participants performed three supervised exercise sessions per week, either 55 min at 50% of whole body peak oxygen uptake (VO(2)peak (low to moderate intensity) or 40 min at 75% of VO(2)peak (moderate to high intensity). Oral glucose tolerance, blood glycated haemoglobin, lipid profile, body composition, maximal workload capacity, whole body and skeletal muscle oxidative capacity and skeletal muscle fibre type composition were assessed before and after 2 and 6 months of intervention. The entire 6 month intervention programme was completed by 37 participants. Continuous endurance-type exercise training reduced blood glycated haemoglobin levels, LDL-cholesterol concentrations, body weight and leg fat mass, and increased VO(2)peak, lean muscle mass and skeletal muscle cytochrome c oxidase and citrate synthase activity (p < 0.05). No differences were observed between the groups training at low to moderate or moderate to high intensity. When matched for energy cost, prolonged continuous low- to moderate-intensity endurance-type exercise training is equally effective as continuous moderate- to high-intensity training in lowering blood glycated haemoglobin and increasing whole body and skeletal muscle oxidative capacity in obese type 2 diabetes patients. ISRCTN32206301 None.

The effects of light emitting diode therapy following high intensity exercise.

PubMed

Denis, Romain; O'Brien, Christopher; Delahunt, Eamonn

2013-05-01

To determine the effects of light emitting diode therapy (LEDT) irradiation on blood lactate concentration ([La]) clearance, peak power output and fatigue index (FI) following high intensity fatiguing exercise. Single-blinded randomised cross-over placebo controlled trial. University College Dublin, Institute for Sport and Health, Human performance laboratory. Eighteen healthy male athletes were recruited from field-based sports (including soccer, hockey and rugby union) and participated in the present study. Dependent variables were the peak power output elicited during the Wingate Anaerobic Test (WAnT), FI and [La] before and after each exercise. WAnT performance was measured prior to high intensity fatiguing exercise (Yo-Yo IR2), prior to LEDT or placebo, and following LEDT or placebo. [La] was measured at baseline, immediately after the Yo-Yo IR2, and in the 3rd, 9th, and 15th min following LEDT or placebo condition. No significant group by treatment interactions were observed for any outcome measures (P > 0.05). We conclude that LEDT irradiation applied following high intensity exercise was not effective and has no immediate effect on [La] clearance, peak power and FI, and thus has no significant effect on muscle recovery in athletes at the intensity and irradiation parameters used in the present study. Further research using different parameters is required to determine how LEDT may contribute to post-exercise recovery. Copyright © 2012 Elsevier Ltd. All rights reserved.

Blood flow patterns during incremental and steady-state aerobic exercise.

PubMed

Coovert, Daniel; Evans, LeVisa D; Jarrett, Steven; Lima, Carla; Lima, Natalia; Gurovich, Alvaro N

2017-05-30

Endothelial shear stress (ESS) is a physiological stimulus for vascular homeostasis, highly dependent on blood flow patterns. Exercise-induced ESS might be beneficial on vascular health. However, it is unclear what type of ESS aerobic exercise (AX) produces. The aims of this study are to characterize exercise-induced blood flow patterns during incremental and steady-state AX. We expect blood flow pattern during exercise will be intensity-dependent and bidirectional. Six college-aged students (2 males and 4 females) were recruited to perform 2 exercise tests on cycleergometer. First, an 8-12-min incremental test (Test 1) where oxygen uptake (VO2), heart rate (HR), blood pressure (BP), and blood lactate (La) were measured at rest and after each 2-min step. Then, at least 48-hr. after the first test, a 3-step steady state exercise test (Test 2) was performed measuring VO2, HR, BP, and La. The three steps were performed at the following exercise intensities according to La: 0-2 mmol/L, 2-4 mmol/L, and 4-6 mmol/L. During both tests, blood flow patterns were determined by high-definition ultrasound and Doppler on the brachial artery. These measurements allowed to determine blood flow velocities and directions during exercise. On Test 1 VO2, HR, BP, La, and antegrade blood flow velocity significantly increased in an intensity-dependent manner (repeated measures ANOVA, p<0.05). Retrograde blood flow velocity did not significantly change during Test 1. On Test 2 all the previous variables significantly increased in an intensity-dependent manner (repeated measures ANOVA, p<0.05). These results support the hypothesis that exercise induced ESS might be increased in an intensity-dependent way and blood flow patterns during incremental and steady-state exercises include both antegrade and retrograde blood flows.

Effects of Different Heavy-Resistance Exercise Protocols on Plasma Beta-Endorphin Concentrations

DTIC Science & Technology

1993-01-01

of O-EP and cortisol. forms of high-intensity exercise, which is performed well above the level that produces V02 .. but uses multi- anaerobic ; opioid...utilizing the Borg CR- ing the rest period length (i.e., from I to 3 min; or in- 10 scale designed to accommodate primarily anaerobic creasing the resistance...O-EP in response to though short-term anaerobic exercise to exhaustion has high-intensity exercise remain unknown, it has been sug- been shown to

Optimizing the "priming" effect: influence of prior exercise intensity and recovery duration on O2 uptake kinetics and severe-intensity exercise tolerance.

PubMed

Bailey, Stephen J; Vanhatalo, Anni; Wilkerson, Daryl P; Dimenna, Fred J; Jones, Andrew M

2009-12-01

It has been suggested that a prior bout of high-intensity exercise has the potential to enhance performance during subsequent high-intensity exercise by accelerating the O(2) uptake (Vo(2)) on-response. However, the optimal combination of prior exercise intensity and subsequent recovery duration required to elicit this effect is presently unclear. Eight male participants, aged 18-24 yr, completed step cycle ergometer exercise tests to 80% of the difference between the preestablished gas exchange threshold and maximal Vo(2) (i.e., 80%Delta) after no prior exercise (control) and after six different combinations of prior exercise intensity and recovery duration: 40%Delta with 3 min (40-3-80), 9 min (40-9-80), and 20 min (40-20-80) of recovery and 70%Delta with 3 min (70-3-80), 9 min (70-9-80), and 20 min (70-20-80) of recovery. Overall Vo(2) kinetics were accelerated relative to control in all conditions except for 40-9-80 and 40-20-80 conditions as a consequence of a reduction in the Vo(2) slow component amplitude; the phase II time constant was not significantly altered with any prior exercise/recovery combination. Exercise tolerance at 80%Delta was improved by 15% and 30% above control in the 70-9-80 and 70-20-80 conditions, respectively, but was impaired by 16% in the 70-3-80 condition. Prior exercise at 40%Delta did not significantly influence exercise tolerance regardless of the recovery duration. These data demonstrate that prior high-intensity exercise ( approximately 70%Delta) can enhance the tolerance to subsequent high-intensity exercise provided that it is coupled with adequate recovery duration (>or=9 min). This combination presumably optimizes the balance between preserving the effects of prior exercise on Vo(2) kinetics and providing sufficient time for muscle homeostasis (e.g., muscle phosphocreatine and H(+) concentrations) to be restored.

Exercise-induced muscle damage and running economy in humans.

PubMed

Assumpção, Cláudio de Oliveira; Lima, Leonardo Coelho Rabello; Oliveira, Felipe Bruno Dias; Greco, Camila Coelho; Denadai, Benedito Sérgio

2013-01-01

Running economy (RE), defined as the energy demand for a given velocity of submaximal running, has been identified as a critical factor of overall distance running performance. Plyometric and resistance trainings, performed during a relatively short period of time (~15-30 days), have been successfully used to improve RE in trained athletes. However, these exercise types, particularly when they are unaccustomed activities for the individuals, may cause delayed onset muscle soreness, swelling, and reduced muscle strength. Some studies have demonstrated that exercise-induced muscle damage has a negative impact on endurance running performance. Specifically, the muscular damage induced by an acute bout of downhill running has been shown to reduce RE during subsequent moderate and high-intensity exercise (>65% VO₂max). However, strength exercise (i.e., jumps, isoinertial and isokinetic eccentric exercises) seems to impair RE only for subsequent high-intensity exercise (~90% VO₂max). Finally, a single session of resistance exercise or downhill running (i.e., repeated bout effect) attenuates changes in indirect markers of muscle damage and blunts changes in RE.

Acute exercise and motor memory consolidation: Does exercise type play a role?

PubMed

Thomas, R; Flindtgaard, M; Skriver, K; Geertsen, S S; Christiansen, L; Korsgaard Johnsen, L; Busk, D V P; Bojsen-Møller, E; Madsen, M J; Ritz, C; Roig, M; Lundbye-Jensen, J

2017-11-01

A single bout of high-intensity exercise can augment off-line gains in skills acquired during motor practice. It is currently unknown if the type of physical exercise influences the effect on motor skill consolidation. This study investigated the effect of three types of high-intensity exercise following visuomotor skill acquisition on the retention of motor memory in 40 young (25.3 ±3.6 years), able-bodied male participants randomly assigned to one of four groups either performing strength training (STR), circuit training (CT), indoor hockey (HOC) or rest (CON). Retention tests of the motor skill were performed 1 (R1h) and 24 h (R1d) post acquisition. For all exercise groups, mean motor performance scores decreased at R1h compared to post acquisition (POST) level; STR (P = 0.018), CT (P = 0.02), HOC (P = 0.014) and performance scores decreased for CT compared to CON (P = 0.049). Mean performance scores increased from POST to R1d for all exercise groups; STR (P = 0.010), CT (P = 0.020), HOC (P = 0.007) while performance scores for CON decreased (P = 0.043). Changes in motor performance were thus greater for STR (P = 0.006), CT (P < 0.001) and HOC (P < 0.001) compared to CON from POST to R1d. The results demonstrate that high-intensity, acute exercise can lead to a decrease in motor performance assessed shortly after motor skill practice (R1h), but enhances offline effects promoting long-term retention (R1d). Given that different exercise modalities produced similar positive off-line effects on motor memory, we conclude that exercise-induced effects beneficial to consolidation appear to depend primarily on the physiological stimulus rather than type of exercise and movements employed. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Experiences of older people with dementia participating in a high-intensity functional exercise program in nursing homes: "While it's tough, it's useful"

PubMed Central

Lundin-Olsson, Lillemor; Skelton, Dawn A.; Lundman, Berit; Rosendahl, Erik

2017-01-01

The objective of the study was to describe the views and experiences of participation in a high-intensity functional exercise (HIFE) program among older people with dementia in nursing homes. The study design was a qualitative interview study with 21 participants (15 women), aged 74–96, and with a Mini-Mental State Examination score of 10–23 at study start. The HIFE-program comprises exercises performed in functional weight-bearing positions and including movements used in everyday tasks. The exercise was individually designed, supervised in small groups in the nursing homes and performed during four months. Interviews were performed directly after exercise sessions and field notes about the sessions were recorded. Qualitative content analysis was used for analyses. The analysis revealed four themes: Exercise is challenging but achievable; Exercise gives pleasure and strength; Exercise evokes body memories; and Togetherness gives comfort, joy, and encouragement. The intense and tailored exercise, adapted to each participant, was perceived as challenging but achievable, and gave pleasure and improvements in mental and bodily strength. Memories of previous physical activities aroused and participants rediscovered bodily capabilities. Importance of individualized and supervised exercise in small groups was emphasized and created feelings of encouragement, safety, and coherence. The findings from the interviews reinforces the positive meaning of intense exercise to older people with moderate to severe dementia in nursing homes. The participants were able to safely adhere to and understand the necessity of the exercise. Providers of exercise should consider the aspects valued by participants, e.g. supervision, individualization, small groups, encouragement, and that exercise involved joy and rediscovery of body competencies. PMID:29149198

Experiences of older people with dementia participating in a high-intensity functional exercise program in nursing homes: "While it's tough, it's useful".

PubMed

Lindelöf, Nina; Lundin-Olsson, Lillemor; Skelton, Dawn A; Lundman, Berit; Rosendahl, Erik

2017-01-01

The objective of the study was to describe the views and experiences of participation in a high-intensity functional exercise (HIFE) program among older people with dementia in nursing homes. The study design was a qualitative interview study with 21 participants (15 women), aged 74-96, and with a Mini-Mental State Examination score of 10-23 at study start. The HIFE-program comprises exercises performed in functional weight-bearing positions and including movements used in everyday tasks. The exercise was individually designed, supervised in small groups in the nursing homes and performed during four months. Interviews were performed directly after exercise sessions and field notes about the sessions were recorded. Qualitative content analysis was used for analyses. The analysis revealed four themes: Exercise is challenging but achievable; Exercise gives pleasure and strength; Exercise evokes body memories; and Togetherness gives comfort, joy, and encouragement. The intense and tailored exercise, adapted to each participant, was perceived as challenging but achievable, and gave pleasure and improvements in mental and bodily strength. Memories of previous physical activities aroused and participants rediscovered bodily capabilities. Importance of individualized and supervised exercise in small groups was emphasized and created feelings of encouragement, safety, and coherence. The findings from the interviews reinforces the positive meaning of intense exercise to older people with moderate to severe dementia in nursing homes. The participants were able to safely adhere to and understand the necessity of the exercise. Providers of exercise should consider the aspects valued by participants, e.g. supervision, individualization, small groups, encouragement, and that exercise involved joy and rediscovery of body competencies.

The influence of high intensity exercise and the Val66Met polymorphism on circulating BDNF and locomotor learning.

PubMed

Helm, Erin E; Matt, Kathleen S; Kirschner, Kenneth F; Pohlig, Ryan T; Kohl, Dave; Reisman, Darcy S

2017-10-01

Brain-derived neurotrophic factor (BDNF) has been directly related to exercise-enhanced motor performance in the neurologically injured animal model; however literature concerning the role of BDNF in the enhancement of motor learning in the human population is limited. Previous studies in healthy subjects have examined the relationship between intensity of an acute bout of exercise, increases in peripheral BDNF and motor learning of a simple isometric upper extremity task. The current study examined the role of high intensity exercise on upregulation of peripheral BDNF levels as well as the role of high intensity exercise in mediation of motor learning and retention of a novel locomotor task in neurologically intact adults. In addition, the impact of a single nucleotide polymorphism in the BDNF gene (Val66Met) in moderating the relationship between exercise and motor learning was explored. It was hypothesized that participation in high intensity exercise prior to practicing a novel walking task (split-belt treadmill walking) would elicit increases in peripheral BDNF as well as promote an increased rate and magnitude of within session learning and retention on a second day of exposure to the walking task. Within session learning and retention would be moderated by the presence or absence of Val66Met polymorphism. Fifty-four neurologically intact participants participated in two sessions of split-belt treadmill walking. Step length and limb phase were measured to assess learning of spatial and temporal parameters of walking. Serum BDNF was collected prior to and immediately following either high intensity exercise or 5min of quiet rest. The results demonstrated that high intensity exercise provides limited additional benefit to learning of a novel locomotor pattern in neurologically intact adults, despite increases in circulating BDNF. In addition, presence of a single nucleotide polymorphism on the BDNF gene did not moderate the magnitude of serum BDNF increases with high intensity exercise, nor did it moderate the relationship between high intensity exercise and locomotor learning. Copyright © 2017 Elsevier Inc. All rights reserved.

Postexercise cold-water immersion improves intermittent high-intensity exercise performance in normothermia.

PubMed

McCarthy, Avina; Mulligan, James; Egaña, Mikel

2016-11-01

A brief cold water immersion between 2 continuous high-intensity exercise bouts improves the performance of the latter compared with passive recovery in the heat. We investigated if this effect is apparent in normothermic conditions (∼19 °C), employing an intermittent high-intensity exercise designed to reflect the work performed at the high-intensity domain in team sports. Fifteen young active men completed 2 exhaustive cycling protocols (Ex1 and Ex2: 12 min at 85% ventilatory threshold (VT) and then an intermittent exercise alternating 30-s at 40% peak power (P peak ) and 30 s at 90% P peak to exhaustion) separated by 15 min of (i) passive rest, (ii) 5-min cold-water immersion at 8 °C, and (iii) 10-min cold-water immersion at 8 °C. Core temperature, heart rate, rates of perceived exertion, and oxygen uptake kinetics were not different during Ex1 among conditions. Time to failure during the intermittent exercise was significantly (P < 0.05) longer during Ex2 following the 5- and 10-min cold-water immersions (7.2 ± 3.5 min and 7.3 ± 3.3 min, respectively) compared with passive rest (5.8 ± 3.1 min). Core temperature, heart rate, and rates of perceived exertion were significantly (P < 0.05) lower during most periods of Ex2 after both cold-water immersions compared with passive rest. The time constant of phase II oxygen uptake response during the 85% VT bout of Ex2 was not different among the 3 conditions. A postexercise, 5- to 10-min cold-water immersion increases subsequent intermittent high-intensity exercise compared with passive rest in normothermia due, at least in part, to reductions in core temperature, circulatory strain, and effort perception.

High-intensity and resistance training and elite young athletes.

PubMed

Ratel, Sébastien

2011-01-01

Although in the past resistance and high-intensity exercise training among young children was the subject of numerous controversies, it is now well-documented that this training mode is a safe and effective means of developing maximal strength, maximal power output and athletic performance in youth, provided that exercises are performed with appropriate supervision and precautions. Muscular strength and power output values measured from vertical jump and Wingate anaerobic tests are higher in elite than in non-elite young athletes and normal children, and the specific training effects on maximal power output normalised for body size are clearly more distinct before puberty. At present, there is no scientific evidence to support the view that high-intensity and/or resistance training might hinder growth and maturation in young children. Pre-pubertal growth is not adversely affected by sport at a competitive level and anthropometric factors are of importance for choice of sport in children. However, coaches, teachers and parents should be aware that unsupervised high-intensity and resistance training programmes involving maximal loads or too frequently repeated resistance exercises increase the risk of injury. Resistance training alone is an effective additional means of developing athletic performance throughout planned youth sports training programmes. Strategies for enhancing the effectiveness and safety of youth resistance and high-intensity exercise training are discussed in this chapter. Copyright © 2011 S. Karger AG, Basel.

Physiologic responses during indoor cycling.

PubMed

Battista, Rebecca A; Foster, Carl; Andrew, Jessica; Wright, Glenn; Lucia, Alejandro; Porcari, John P

2008-07-01

During the last decade, there has been active interest in indoor cycling (e.g., spinning) as a method of choreographed group exercise. Recent studies have suggested that exercise intensity during indoor cycling may be quite high and may transiently exceed Vo2max. This study sought to confirm these findings, as the apparent high intensity of indoor cycling has implications for both the efficacy and the risk of indoor cycling as an exercise method. Twenty healthy female students performed an incremental exercise test to define Vo2max and performed 2 videotaped indoor exercise classes lasting 45 minutes and 35 minutes. Vo2, heart rate (HR), and rating of perceived exertion (RPE) were measured during the indoor cycling classes, with Vo2 data integrated in 30-second intervals. The mean %Vo2max during the indoor cycling classes was modest (74 +/- 14% Vo2max and 66 +/- 14%Vo2max, respectively). However, 52% and 35% of the time during the 45- and 35-minute classes was spent at intensities greater than the ventilatory threshold (VT). The HR response indicated that 35% and 38% of the session time was above the HR associated with VT. In 10 of the 40 exercise sessions, there were segments in which the momentary Vo2 exceeded Vo2max observed during incremental testing, and the cumulative time with exercise intensity greater than Vo2max ranged from 0.5 to 14.0 minutes. It can be concluded that although the intensity of indoor cycling in healthy, physically active women is moderate, there are frequent observations of transient values of Vo2 exceeding Vo2max, and a substantial portion of the exercise bouts at intensities greater than VT. As such, the data suggest that indoor cycling must be considered a high-intensity exercise mode of exercise training, which has implications for both efficacy and risk.

Energy cost of isolated resistance exercises across low- to high-intensities

PubMed Central

Garrido, Nuno Domingos; Vianna, Jeferson; Sousa, Ana Catarina; Alves, José Vilaça; Marques, Mário Cardoso

2017-01-01

This study aimed to estimate the energy cost across various intensities at eight popular resistance exercises: half squat, 45° inclined leg press, leg extension, horizontal bench press, 45° inclined bench press, lat pull down, triceps extension and biceps curl. 58 males (27.5 ± 4.9 years, 1.78 ± 0.06 m height, 78.67 ± 10.7 kg body mass and 11.4 ± 4.1% estimated body fat) were randomly divided into four groups of 14 subjects each. For each group, two exercises were randomly assigned and on different days, they performed four bouts of 5-min constant-intensity for each of the two assigned exercises: 12%, 16%, 20% and 24% 1-RM. Later, the subjects performed exhaustive bouts at 80% 1-RM in the same two exercises. The mean values of VO2 at the last 30s of exercise at 12, 16, 20 and 24% 1-RM bouts were plotted against relative intensity (% 1-RM) in a simple linear regression mode. The regressions were then used to predict O2 demand for the higher intensity (80% 1-RM). Energy cost rose linearly with exercise intensity in every exercise with the lowest mean values were found in biceps curl and the highest in half squat exercise (p<0.001). Half squat exercise presented significant (p<0.001) higher values of energy cost in all intensities, when compared with the remaining exercises. This study revealed that low-intensity resistance exercise provides energy cost comprised between 3 and 10 kcal∙min-1. Energy cost rose past 20 kcal∙min-1 at 80% 1-RM in leg exercise. In addition, at 80% 1-RM, it was found that upper body exercises are less anaerobic than lower-body exercises. PMID:28742112

High-intensity interval running is perceived to be more enjoyable than moderate-intensity continuous exercise: implications for exercise adherence.

PubMed

Bartlett, Jonathan D; Close, Graeme L; MacLaren, Don P M; Gregson, Warren; Drust, Barry; Morton, James P

2011-03-01

The aim of this study was to objectively quantify ratings of perceived enjoyment using the Physical Activity Enjoyment Scale following high-intensity interval running versus moderate-intensity continuous running. Eight recreationally active men performed two running protocols consisting of high-intensity interval running (6 × 3 min at 90% VO(2max) interspersed with 6 × 3 min active recovery at 50% VO(2max) with a 7-min warm-up and cool down at 70% VO(2max)) or 50 min moderate-intensity continuous running at 70% VO(2max). Ratings of perceived enjoyment after exercise were higher (P < 0.05) following interval running compared with continuous running (88 ± 6 vs. 61 ± 12) despite higher (P < 0.05) ratings of perceived exertion (14 ± 1 vs. 13 ± 1). There was no difference (P < 0.05) in average heart rate (88 ± 3 vs. 87 ± 3% maximum heart rate), average VO(2) (71 ± 6 vs. 73 ± 4%VO(2max)), total VO(2) (162 ± 16 vs. 166 ± 27 L) or energy expenditure (811 ± 83 vs. 832 ± 136 kcal) between protocols. The greater enjoyment associated with high-intensity interval running may be relevant for improving exercise adherence, since running is a low-cost exercise intervention requiring no exercise equipment and similar relative exercise intensities have previously induced health benefits in patient populations.

The effect of low and high-intensity cycling in diesel exhaust on flow-mediated dilation, circulating NOx, endothelin-1 and blood pressure

PubMed Central

Tebbutt, Scott J.; Carlsten, Christopher; Koehle, Michael S.

2018-01-01

Introduction Exposure to air pollution impairs aspects of endothelial function such as flow-mediated dilation (FMD). Outdoor exercisers are frequently exposed to air pollution, but how exercising in air pollution affects endothelial function and how these effects are modified by exercise intensity are poorly understood. Objectives Therefore, the purpose of this study was to determine the effects of low-intensity and high-intensity cycling with diesel exhaust (DE) exposure on FMD, blood pressure, plasma nitrite and nitrate (NOx) and endothelin-1. Methods Eighteen males performed 30-minute trials of low or high-intensity cycling (30% and 60% of power at VO2peak) or a resting control condition. For each subject, each trial was performed once while breathing filtered air (FA) and once while breathing DE (300ug/m3 of PM2.5, six trials in total). Preceding exposure, immediately post-exposure, 1 hour and 2 hours post-exposure, FMD, blood pressure and plasma endothelin-1 and NOx concentrations were measured. Data were analyzed using repeated-measures ANOVA and linear mixed model. Results Following exercise in DE, plasma NOx significantly increased and was significantly greater than FA (p<0.05). Two hours following DE exposure, endothelin-1 was significantly less than FA (p = 0.037) but exercise intensity did not modify this response. DE exposure did not affect FMD or blood pressure. Conclusion Our results suggest that exercising in DE did not adversely affect plasma NOX, endothelin-1, FMD and blood pressure. Therefore, recommendations for healthy individuals to moderate or avoid exercise during bouts of high pollution appear to have no acute protective effect. PMID:29466393

Exercise Guidelines to Promote Cardiometabolic Health in Spinal Cord Injured Humans: Time to Raise the Intensity?

PubMed

Nightingale, Tom E; Metcalfe, Richard S; Vollaard, Niels B; Bilzon, James L

2017-08-01

Spinal cord injury (SCI) is a life-changing event that, as a result of paralysis, negatively influences habitual levels of physical activity and hence cardiometabolic health. Performing regular structured exercise therefore appears extremely important in persons with SCI. However, exercise options are mainly limited to the upper body, which involves a smaller activated muscle mass compared with the mainly leg-based activities commonly performed by nondisabled individuals. Current exercise guidelines for SCI focus predominantly on relative short durations of moderate-intensity aerobic upper-body exercise, yet contemporary evidence suggests this is not sufficient to induce meaningful improvements in risk factors for the prevention of cardiometabolic disease in this population. As such, these guidelines and their physiological basis require reappraisal. In this special communication, we propose that high-intensity interval training (HIIT) may be a viable alternative exercise strategy to promote vigorous-intensity exercise and prevent cardiometabolic disease in persons with SCI. Supplementing the limited data from SCI cohorts with consistent findings from studies in nondisabled populations, we present strong evidence to suggest that HIIT is superior to moderate-intensity aerobic exercise for improving cardiorespiratory fitness, insulin sensitivity, and vascular function. The potential application and safety of HIIT in this population is also discussed. We conclude that increasing exercise intensity could offer a simple, readily available, time-efficient solution to improve cardiometabolic health in persons with SCI. We call for high-quality randomized controlled trials to examine the efficacy and safety of HIIT in this population. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Beetroot Juice Supplementation Improves High-Intensity Intermittent Type Exercise Performance in Trained Soccer Players.

PubMed

Nyakayiru, Jean; Jonvik, Kristin L; Trommelen, Jorn; Pinckaers, Philippe J M; Senden, Joan M; van Loon, Luc J C; Verdijk, Lex B

2017-03-22

It has been shown that nitrate supplementation can enhance endurance exercise performance. Recent work suggests that nitrate ingestion can also increase intermittent type exercise performance in recreational athletes. We hypothesized that six days of nitrate supplementation can improve high-intensity intermittent type exercise performance in trained soccer players. Thirty-two male soccer players (age: 23 ± 1 years, height: 181 ± 1 m, weight: 77 ± 1 kg, playing experience: 15.2 ± 0.5 years, playing in the first team of a 2nd or 3rd Dutch amateur league club) participated in this randomized, double-blind cross-over study. All subjects participated in two test days in which high-intensity intermittent running performance was assessed using the Yo-Yo IR1 test. Subjects ingested nitrate-rich (140 mL; ~800 mg nitrate/day; BR) or a nitrate-depleted beetroot juice (PLA) for six subsequent days, with at least eight days of wash-out between trials. The distance covered during the Yo-Yo IR1 was the primary outcome measure, while heart rate (HR) was measured continuously throughout the test, and a single blood and saliva sample were collected just prior to the test. Six days of BR ingestion increased plasma and salivary nitrate and nitrite concentrations in comparison to PLA ( p < 0.001), and enhanced Yo-Yo IR1 test performance by 3.4 ± 1.3% (from 1574 ± 47 to 1623 ± 48 m; p = 0.027). Mean HR was lower in the BR (172 ± 2) vs. PLA trial (175 ± 2; p = 0.014). Six days of BR ingestion effectively improves high-intensity intermittent type exercise performance in trained soccer players.

Beetroot Juice Supplementation Improves High-Intensity Intermittent Type Exercise Performance in Trained Soccer Players

PubMed Central

Nyakayiru, Jean; Jonvik, Kristin L.; Trommelen, Jorn; Pinckaers, Philippe J. M.; Senden, Joan M.; van Loon, Luc J. C.; Verdijk, Lex B.

2017-01-01

It has been shown that nitrate supplementation can enhance endurance exercise performance. Recent work suggests that nitrate ingestion can also increase intermittent type exercise performance in recreational athletes. We hypothesized that six days of nitrate supplementation can improve high-intensity intermittent type exercise performance in trained soccer players. Thirty-two male soccer players (age: 23 ± 1 years, height: 181 ± 1 m, weight: 77 ± 1 kg, playing experience: 15.2 ± 0.5 years, playing in the first team of a 2nd or 3rd Dutch amateur league club) participated in this randomized, double-blind cross-over study. All subjects participated in two test days in which high-intensity intermittent running performance was assessed using the Yo-Yo IR1 test. Subjects ingested nitrate-rich (140 mL; ~800 mg nitrate/day; BR) or a nitrate-depleted beetroot juice (PLA) for six subsequent days, with at least eight days of wash-out between trials. The distance covered during the Yo-Yo IR1 was the primary outcome measure, while heart rate (HR) was measured continuously throughout the test, and a single blood and saliva sample were collected just prior to the test. Six days of BR ingestion increased plasma and salivary nitrate and nitrite concentrations in comparison to PLA (p < 0.001), and enhanced Yo-Yo IR1 test performance by 3.4 ± 1.3% (from 1574 ± 47 to 1623 ± 48 m; p = 0.027). Mean HR was lower in the BR (172 ± 2) vs. PLA trial (175 ± 2; p = 0.014). Six days of BR ingestion effectively improves high-intensity intermittent type exercise performance in trained soccer players. PMID:28327503

Impact of high-intensity interval training and moderate-intensity continuous training on resting and postexercise cardiac troponin T concentration.

PubMed

Nie, Jinlei; Zhang, Haifeng; Kong, Zhaowei; George, Keith; Little, Jonathan P; Tong, Tomas K; Li, Feifei; Shi, Qingde

2018-03-01

What is the central question of this study? Does exercise training impact resting and postexercise cardiac troponin T (cTnT) concentration? What is the main finding and its importance? This randomized controlled intervention study demonstrated that 12 weeks of either high-intensity interval training or moderate-intensity continuous training largely abolished the exercise-induced elevation in cTnT when exercise was performed at the same absolute intensity. There was no impact of training on resting cTnT or postexercise appearance of cTnT when exercise was performed at the same relative intensity. These findings provide new information that might help clinicians with decision-making in relationship to basal and postexercise values of cTnT in individuals with different training status. We evaluated the influence of 12 weeks of high-intensity interval training [HIIT; repeated 4 min cycling at 90% of maximal oxygen uptake (V̇O2max) interspersed with 3 min rest, 200-300 kJ per session, 3 or 4 days each week] and work-equivalent moderate-intensity continuous training (MICT; continuous cycling at 60% V̇O2max) on resting cardiac troponin T (cTnT) and the appearance of exercise-induced cTnT. Forty-eight sedentary obese young women were randomly assigned to HIIT, MICT or a control group. The V̇O2max and body composition were measured before and after training. At baseline, cTnT was assessed using a high-sensitivity assay at rest and immediately, 2 and 4 h after 45 min cycling at 60% V̇O2max. After a 12 week training period, cTnT was assessed before and after 45 min cycling at the same relative and absolute intensities as before training. Training led to higher V̇O2max and lower fat mass in both HIIT and MICT groups (all P < 0.05). Before training, cTnT was significantly elevated in all three groups (by 35-118%, all P < 0.05) with acute exercise. After training, both resting and postexercise cTnT concentrations (same relative intensity) were similar to pretraining values. In contrast, postexercise cTnT (same absolute intensity, which represented a smaller exercise stimulus) was not elevated from rest in both HIIT and MICT groups. In conclusion, 12 weeks of either HIIT or MICT largely abolished the postexercise elevation of cTnT concentration when exercise was performed at the same absolute intensity. There was, however, no impact of training on resting cTnT or postexercise appearance of cTnT for exercise performed at the same relative intensity. © 2017 The Authors. Experimental Physiology © 2017 The Physiological Society.

Impact of intensive high-fat ingestion in the early stage of recovery from exercise training on substrate metabolism during exercise in humans.

PubMed

Ichinose, Takashi; Arai, Natsuko; Nagasaka, Tomoaki; Asano, Masaya; Hashimoto, Kenji

2012-01-01

Not only increasing body carbohydrate (CHO) stores before exercise but also suppressing CHO oxidation during exercise is important for improving endurance performance. We tested the hypothesis that intensive high-fat ingestion in the early stage of recovery from exercise training (ET) for 2 d would suppress CHO oxidation during exercise by increasing whole body lipolysis and/or fat oxidation. In a randomized crossover design, on days 1 and 2, six male subjects performed cycle ET at 50% peak oxygen consumption (VO(2 peak)) for 60-90 min, and consumed a control diet (CON: 1,224 kcal, 55% carbohydrate, 30% fat) or the same diet supplemented with high fat (HF: 1,974 kcal, 34% carbohydrate, 56% fat) 1 h after ET, with the diet other than post-ET similar in both trials. On day 3, subjects performed cycle exercise at 65% VO(2 peak) until exhaustion. Exercise time to exhaustion was longer in the HF trial than in the CON trial (CON: 48.9 ± 6.7 vs. HF: 55.8 ± 7.7 min, p<0.05). In the HF trial, total fat oxidation until exhaustion was higher, accompanied by higher post-exercise plasma glycerol concentration, than in the CON trial (CON: 213 ± 54 vs. HF: 286 ± 63 kcal, p<0.05), whereas total carbohydrate oxidation until exhaustion was not different between trials. These results suggest that intensive high-fat ingestion in the early stage of recovery from ET for a few days until the day before exercise was an effective means of eliciting a CHO-sparing effect during exercise by enhancing fat metabolism.

No Effect of Exercise Intensity on Appetite in Highly-Trained Endurance Women

PubMed Central

Howe, Stephanie M.; Hand, Taryn M.; Larson-Meyer, D. Enette; Austin, Kathleen J.; Alexander, Brenda M.; Manore, Melinda M.

2016-01-01

In endurance-trained men, an acute bout of exercise is shown to suppress post-exercise appetite, yet limited research has examined this response in women. The purpose of this study was to investigate the effect of exercise intensity on appetite and gut hormone responses in endurance-trained women. Highly-trained women (n = 15, 18–40 years, 58.4 ± 6.4 kg, VO2MAX = 55.2 ± 4.3 mL/kg/min) completed isocaloric bouts (500 kcals or 2093 kJ) of moderate-intensity (MIE, 60% VO2MAX) and high-intensity (HIE, 85% VO2MAX) treadmill running at the same time of day, following a similar 48-h diet/exercise period, and at least 1-week apart. Blood was drawn pre-exercise (baseline), immediately post-exercise and every 20-min for the next 60-min. Plasma concentrations of acylated ghrelin, PYY3–36, GLP-1 and subjective appetite ratings via visual analog scale (VAS) were assessed at each time point. Acylated ghrelin decreased (p = 0.014) and PYY3–36 and GLP-1 increased (p = 0.036, p < 0.0001) immediately post-exercise, indicating appetite suppression. VAS ratings of hunger and desire to eat decreased immediately post-exercise (p = 0.0012, p = 0.0031, respectively), also indicating appetite suppression. There were no differences between exercise intensities for appetite hormones or VAS. Similar to males, post-exercise appetite regulatory hormones were altered toward suppression in highly-trained women and independent of energy cost of exercise. Results are important for female athletes striving to optimize nutrition for endurance performance. PMID:27096869

Impact of High-intensity Intermittent and Moderate-intensity Continuous Exercise on Autonomic Modulation in Young Men.

PubMed

Cabral-Santos, C; Giacon, T R; Campos, E Z; Gerosa-Neto, J; Rodrigues, B; Vanderlei, L C M; Lira, F S

2016-06-01

The aim of this study was to compare heart rate variability (HRV) recovery after two iso-volume (5 km) exercises performed at different intensities. 14 subjects volunteered (25.17±5.08 years; 74.7±6.28 kg; 175±0.05 cm; 59.56±5.15 mL·kg(-1)·min(-1)) and after determination of peak oxygen uptake (VO2Peak) and the speed associated with VO2Peak (sVO2Peak), the subjects completed 2 random experimental trials: high-intensity exercise (HIE - 1:1 at 100% sVO2Peak), and moderate-intensity continuous exercise (MIE - 70% sVO2Peak). HRV and RR intervals were monitored before, during and after the exercise sessions together with, the HRV analysis in the frequency domains (high-frequency - HF: 0.15 to 0.4 Hz and low-frequency - LF: 0.04 to 0.15 Hz components) and the ratio between them (LF/HF). Statistical analysis comparisons between moments and between HIE and MIE were performed using a mixed model. Both exercise sessions modified LFlog, HFlog, and LF/HF (F=16.54, F=19.32 and F=5.17, p<0.05, respectively). A group effect was also found for LFlog (F=23.91, p<0.05), and HFlog (F=57.55, p< 0.05). LF/HF returned to resting value 15 min after MIE exercise and 20 min after HIE exercise. This means that the heavy domain (aerobic and anaerobic threshold) induces dissimilar autonomic modification in physically active subjects. Both HIE and MIE modify HRV, and generally HIE delays parasympathetic autonomic modulation recovery after iso-volume exercise. © Georg Thieme Verlag KG Stuttgart · New York.

Moderate-to-High Intensity Physical Exercise in Patients with Alzheimer's Disease: A Randomized Controlled Trial.

PubMed

Hoffmann, Kristine; Sobol, Nanna A; Frederiksen, Kristian S; Beyer, Nina; Vogel, Asmus; Vestergaard, Karsten; Brændgaard, Hans; Gottrup, Hanne; Lolk, Annette; Wermuth, Lene; Jacobsen, Søren; Laugesen, Lars P; Gergelyffy, Robert G; Høgh, Peter; Bjerregaard, Eva; Andersen, Birgitte B; Siersma, Volkert; Johannsen, Peter; Cotman, Carl W; Waldemar, Gunhild; Hasselbalch, Steen G

2016-01-01

Studies of physical exercise in patients with Alzheimer's disease (AD) are few and results have been inconsistent. To assess the effects of a moderate-to-high intensity aerobic exercise program in patients with mild AD. In a randomized controlled trial, we recruited 200 patients with mild AD to a supervised exercise group (60-min sessions three times a week for 16 weeks) or to a control group. Primary outcome was changed from baseline in cognitive performance estimated by Symbol Digit Modalities Test (SDMT) in the intention-to-treat (ITT) group. Secondary outcomes included changes in quality of life, ability to perform activities of daily living, and in neuropsychiatric and depressive symptoms. The ITT analysis showed no significant differences between intervention and control groups in change from baseline of SDMT, other cognitive tests, quality of life, or activities of daily living. The change from baseline in Neuropsychiatric Inventory differed significantly in favor of the intervention group (mean: -3.5, 95% confidence interval (CI) -5.8 to -1.3, p = 0.002). In subjects who adhered to the protocol, we found a significant effect on change from baseline in SDMT as compared with the control group (mean: 4.2, 95% CI 0.5 to 7.9, p = 0.028), suggesting a dose-response relationship between exercise and cognition. This is the first randomized controlled trial with supervised moderate-to-high intensity exercise in patients with mild AD. Exercise reduced neuropsychiatric symptoms in patients with mild AD, with possible additional benefits of preserved cognition in a subgroup of patients exercising with high attendance and intensity.

Muscle metabolic and neuromuscular determinants of fatigue during cycling in different exercise intensity domains

PubMed Central

Black, Matthew I.; Jones, Andrew M.; Blackwell, Jamie R.; Bailey, Stephen J.; Wylie, Lee J.; McDonagh, Sinead T. J.; Thompson, Christopher; Kelly, James; Sumners, Paul; Mileva, Katya N.; Bowtell, Joanna L.

2017-01-01

Lactate or gas exchange threshold (GET) and critical power (CP) are closely associated with human exercise performance. We tested the hypothesis that the limit of tolerance (Tlim) during cycle exercise performed within the exercise intensity domains demarcated by GET and CP is linked to discrete muscle metabolic and neuromuscular responses. Eleven men performed a ramp incremental exercise test, 4–5 severe-intensity (SEV; >CP) constant-work-rate (CWR) tests until Tlim, a heavy-intensity (HVY; GET) CWR test until Tlim, and a moderate-intensity (MOD; 0.05) muscle metabolic milieu (i.e., low pH and [PCr] and high [lactate]) was attained at Tlim (approximately 2–14 min) for all SEV exercise bouts. The muscle metabolic perturbation was greater at Tlim following SEV compared with HVY, and also following SEV and HVY compared with MOD (all P < 0.05). The normalized M-wave amplitude for the vastus lateralis (VL) muscle decreased to a similar extent following SEV (−38 ± 15%), HVY (−68 ± 24%), and MOD (−53 ± 29%), (P > 0.05). Neural drive to the VL increased during SEV (4 ± 4%; P < 0.05) but did not change during HVY or MOD (P > 0.05). During SEV and HVY, but not MOD, the rates of change in M-wave amplitude and neural drive were correlated with changes in muscle metabolic ([PCr], [lactate]) and blood ionic/acid-base status ([lactate], [K+]) (P < 0.05). The results of this study indicate that the metabolic and neuromuscular determinants of fatigue development differ according to the intensity domain in which the exercise is performed. NEW & NOTEWORTHY The gas exchange threshold and the critical power demarcate discrete exercise intensity domains. For the first time, we show that the limit of tolerance during whole-body exercise within these domains is characterized by distinct metabolic and neuromuscular responses. Fatigue development during exercise greater than critical power is associated with the attainment of consistent “limiting” values of muscle metabolites, whereas substrate availability and limitations to muscle activation may constrain performance at lower intensities. PMID:28008101

High-intensity interval training using whole-body exercises: training recommendations and methodological overview.

PubMed

Machado, Alexandre F; Baker, Julien S; Figueira Junior, Aylton J; Bocalini, Danilo S

2017-05-04

HIIT whole body (HWB)-based exercise is a new calisthenics exercise programme approach that can be considered an effective and safe method to improve physical fitness and body composition. HWB is a method that can be applied to different populations and ages. The purpose of this study was to describe possible methodologies for performing physical training based on whole-body exercise in healthy subjects. The HWB sessions consist of a repeated stimulus based on high-intensity exercise that also include monitoring time to effort, time to recuperation and session time. The exercise intensity is related to the maximal number of movements possible in a given time; therefore, the exercise sessions can be characterized as maximal. The intensity can be recorded using ratings of perceived exertion. Weekly training frequency and exercise selection should be structured according to individual subject functional fitness. Using this simple method, there is potential for greater adherence to physical activity which can promote health benefits to all members of society. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Time motion and video analysis of classical ballet and contemporary dance performance.

PubMed

Wyon, M A; Twitchett, E; Angioi, M; Clarke, F; Metsios, G; Koutedakis, Y

2011-11-01

Video analysis has become a useful tool in the preparation for sport performance and its use has highlighted the different physiological demands of seemingly similar sports and playing positions. The aim of the current study was to examine the performance differences between classical ballet and contemporary dance. In total 93 dance performances (48 ballet and 45 contemporary) were analysed for exercise intensity, changes in direction and specific discrete skills (e. g., jumps, lifts). Results revealed significant differences between the 2 dance forms for exercise intensity (p<0.001), changes in direction (p<0.001) and discrete skills (p<0.05) with gender differences noted in the latter (p<0.05). Ballet was characterised by longer periods at rest (38 s x min(-1)) and high to very high exercise intensities (9 s x min(-1)), whilst contemporary dance featured more continuous moderate exercise intensities (27 s x min(-1)). These differences have implications on the energy systems utilised during performance with ballet potentially stressing the anaerobic system more than contemporary dance. The observed high rates in the discrete skills in ballet (5 jumps x min(-1); 2 lifts x min(-1)) can cause local muscular damage, particularly in relatively weaker individuals. In conclusion, classical ballet and contemporary dance performances are as significantly different in the underlying physical demands placed on their performers as the artistic aspects of the choreography. © Georg Thieme Verlag KG Stuttgart · New York.

Social Bonds and Exercise: Evidence for a Reciprocal Relationship

PubMed Central

Davis, Arran; Taylor, Jacob; Cohen, Emma

2015-01-01

In two experimental studies, we investigated mechanisms hypothesized to underpin two pervasive and interrelated phenomena: that certain forms of group movement and exercise lead to social bonding and that social bonding can lead to enhanced exercise performance. In Study 1, we manipulated synchrony and exercise intensity among rowers and found that, compared with low intensity exercise, moderate intensity exercise led to significantly higher levels of cooperation in an economic game; no effect of synchrony vs. non-synchrony was found. In Study 2, we investigated the effects of bonding on performance, using synchrony as a cue of existing supportive social bonds among participants. An elite, highly bonded team of rugby players participated in solo, synchronized, and non-synchronized warm-up sessions; participants' anaerobic performance significantly improved after the brief synchronous warm-up relative to the non-synchronous warm-up. The findings substantiate claims concerning the reciprocal links between group exercise and social bonding, and may help to explain the ubiquity of collective physical activity across cultural domains as varied as play, ritual, sport, and dance. PMID:26317514

Influence of acute high-intensity aerobic interval exercise bout on selective attention and short-term memory tasks.

PubMed

Alves, Christiano R R; Tessaro, Victor H; Teixeira, Luis A C; Murakava, Karina; Roschel, Hamilton; Gualano, Bruno; Takito, Monica Y

2014-02-01

Acute moderate intensity continuous aerobic exercise can improve specific cognitive functions, such as short-term memory and selective attention. Moreover, high-intensity interval training (HIT) has been recently proposed as a time-efficient alternative to traditional cardiorespiratory exercise. However, considering previous speculations that the exercise intensity affects cognition in a U-shaped fashion, it was hypothesized that a HIT session may impair cognitive performance. Therefore, this study assessed the effects of an acute HIT session on selective attention and short-term memory tasks. 22 healthy middle-aged individuals (M age = 53.7 yr.) engaged in both (1) a HIT session, 10 1 min. cycling bouts at the intensity corresponding to 80% of the reserve heart rate interspersed by 1 min. active pauses cycling at 60% of the reserve heart rate and (2) a control session, consisting of an active condition with low-intensity active stretching exercise. Before and after each experimental session, cognitive performance was assessed by the Victoria Version of the Stroop test (a selective attention test) and the Digit Span test (a short-term memory test). Following the HIT session, the time to complete the Stroop "Color word" test was significantly lower when compared with that of the control session. The performances in the other subtasks of the Stroop test as well as in the Digit Span test were not significantly different. A HIT session can improve cognitive function.

Greater impact of acute high-intensity interval exercise on post-exercise executive function compared to moderate-intensity continuous exercise.

PubMed

Tsukamoto, Hayato; Suga, Tadashi; Takenaka, Saki; Tanaka, Daichi; Takeuchi, Tatsuya; Hamaoka, Takafumi; Isaka, Tadao; Hashimoto, Takeshi

2016-03-01

Aerobic moderate-intensity continuous exercise (MCE) can improve executive function (EF) acutely, potentially through the activation of both physiological and psychological factors. Recently, high-intensity interval exercise (HIIE) has been reported to be more beneficial for physical adaptation than MCE. Factors for EF improvement can potentially be more enhanced by HIIE than by MCE; but the effects of HIIE on EF remain unknown. Therefore, we aimed to examine to what extent HIIE impacts post-exercise EF immediately after exercise and during post-exercise recovery, compared with traditional MCE. Twelve healthy male subjects performed cycle ergometer exercise based on either HIIE or MCE protocols in a randomized and counterbalanced order. The HIIE protocol consisted of four 4-min bouts at 90% of peak VO2 with 3-min active recovery at 60% of peak VO2. A volume-matched MCE protocol was applied at 60% of peak VO2. To evaluate EF, a color-words Stroop task was performed pre- and post-exercise. Improvement in EF immediately after exercise was the same for the HIIE and MCE protocols. However, the improvement of EF by HIIE was sustained during 30 min of post-exercise recovery, during which MCE returned to the pre-exercise level. The EF response in the post-exercise recovery was associated with changes in physiological and psychological responses. The present findings showed that HIIE and MCE were capable of improving EF. Moreover, HIIE could prolong improvement in EF during post-exercise recovery. For the first time, we suggest that HIIE may be more effective strategy than MCE for improving EF. Copyright © 2015 Elsevier Inc. All rights reserved.

Global Metabolic Stress of Isoeffort Continuous and High Intensity Interval Aerobic Exercise: A Comparative 1H NMR Metabonomic Study.

PubMed

Zafeiridis, Andreas; Chatziioannou, Anastasia Chrysovalantou; Sarivasiliou, Haralambos; Kyparos, Antonios; Nikolaidis, Michalis G; Vrabas, Ioannis S; Pechlivanis, Alexandros; Zoumpoulakis, Panagiotis; Baskakis, Constantinos; Dipla, Konstantina; Theodoridis, Georgios A

2016-12-02

The overall metabolic/energetic stress that occurs during an acute bout of exercise is proposed to be the main driving force for long-term training adaptations. Continuous and high-intensity interval exercise protocols (HIIE) are currently prescribed to acquire the muscular and metabolic benefits of aerobic training. We applied 1 H NMR-based metabonomics to compare the overall metabolic perturbation and activation of individual bioenergetic pathways of three popular aerobic exercises matched for effort/strain. Nine men performed continuous, long-interval (3 min), and short-interval (30 s) bouts of exercise under isoeffort conditions. Blood was collected before and after exercise. The multivariate PCA and OPLS-DA models showed a distinct separation of pre- and postexercise samples in three protocols. The two models did not discriminate the postexercise overall metabolic profiles of the three exercise types. Analysis focused on muscle bioenergetic pathways revealed an extensive upregulation of carbohydrate-lipid metabolism and the TCA cycle in all three protocols; there were only a few differences among protocols in the postexercise abundance of molecules when long-interval bouts were performed. In conclusion, continuous and HIIE exercise protocols, when performed with similar effort/strain, induce comparable global metabolic response/stress despite their marked differences in work-bout intensities. This study highlights the importance of NMR metabonomics in comprehensive monitoring of metabolic consequences of exercise training in the blood of athletes and exercising individuals.

[Effect of high-intensity interval training on the reduction of glycosylated hemoglobin in type-2 diabetic adult patients].

PubMed

Aguilera Eguía, Raúl Alberto; Russell Guzmán, Javier Antonio; Soto Muñoz, Marcelo Enrique; Villegas González, Bastián Eduardo; Poblete Aro, Carlos Emilio; Ibacache Palma, Alejandro

2015-03-05

Type 2 diabetes mellitus is one of the major non-communicable chronic diseases in the world. Its prevalence in Chile is significant, and complications associated with this disease involve great costs, which is why prevention and treatment of this condition are essential. Physical exercise is an effective means for prevention and treatment of type 2 diabetes mellitus. The emergence of new forms of physical training, such as "high intensity interval training", presents novel therapeutic alternatives for patients and health care professionals. To assess the validity and applicability of the results regarding the effectiveness of high intensity interval training in reducing glycosylated hemoglobin in adult patients with type 2 diabetes mellitus and answer the following question: In subjects with type 2 diabetes, can the method of high intensity interval training compared to moderate intensity exercise decrease glycosylated hemoglobin? We performed a critical analysis of the article "Feasibility and preliminary effectiveness of high intensity interval training in type 2 diabetes". We found no significant differences in the amount of glycosylated hemoglobin between groups of high intensity interval training and moderate-intensity exercise upon completion of the study (p>0.05). In adult patients with type 2 diabetes mellitus, high intensity interval training does not significantly improve glycosylated hemoglobin levels. Despite this, the high intensity interval training method shows as much improvement in body composition and physical condition as the moderate intensity exercise program.

Exercise intensity of cycle-touring events.

PubMed

Neumayr, G; Pfister, R; Mitterbauer, G; Gaenzer, H; Sturm, W; Eibl, G; Hoertnagl, H

2002-10-01

The aim of the study was to analyze the exercise intensity of recreational cyclists participating in a cycling-touring event. In 14 male healthy recreational cyclists heart rate (HR) monitoring was performed during the Otztal Radmarathon 1999 (distance: 230 km; altitude difference: 5500 m) in order to evaluate the HR response and to estimate the cardiopulmonary strains for the less-trained athlete confronted with such a marathon. Four different exercise intensities were defined as percentages of maximal HR (HR(max)) as follows: recovery HR (HR(re)) < 70 % of HR max; moderate aerobic HR (HR(ma)) = 70 - 80 %; intense aerobic HR (HR(ia)) = 80 - 90 %; and anaerobic HR (HR(an)) > 90 %. All athletes finished the competition successfully. The mean racing time was 10 h 14 min, the average speed 22.5 km/h. The mean HR(max) was 188 bpm, the average value of the measured HRs (HR(average)) was 145 bpm resulting in a mean HR(average)/HR(max) ratio of 0.77. Athletes spent 18.5 % (1 h 54 min) of total race time within HR(re), 28 % (2 h 52 min) within HR(ma), 39.5 % (4 h 02 min) within HR(ia), and 14 % (1 h 26 min) within HR(an). The vast majority of exercise was done under "aerobic conditions" (HR(re) + HR(ma) + HR(ia) = 86 % or 8 h 48 min) - confirming the knowledge that the aerobic energy supply is crucial for the performance of long-term exercise. The large amount of high exercise intensities (HR(ia) + HR(an) = 53.5 % or 5 h 30 min), however, features the intense cardiopulmonary strains evoked by such competitions. The HR response was related to the course profile with HRs significantly declining in all subjects to an extent of 10 % during the course of race. Our findings show that the exercise intensity borne by recreational cyclists during a cycle-touring event is high and very similar to that of professionals. With respect to the high cardiovascular strains a thorough medical screening is advisable for any participant of such an event combining both high volume and high intensity loads.

Acute administration of high doses of taurine does not substantially improve high-intensity running performance and the effect on maximal accumulated oxygen deficit is unclear.

PubMed

Milioni, Fabio; Malta, Elvis de Souza; Rocha, Leandro George Spinola do Amaral; Mesquita, Camila Angélica Asahi; de Freitas, Ellen Cristini; Zagatto, Alessandro Moura

2016-05-01

The aim of the present study was to investigate the effects of acute administration of taurine overload on time to exhaustion (TTE) of high-intensity running performance and alternative maximal accumulated oxygen deficit (MAODALT). The study design was a randomized, placebo-controlled, crossover design. Seventeen healthy male volunteers (age: 25 ± 6 years; maximal oxygen uptake: 50.5 ± 7.6 mL·kg(-1)·min(-1)) performed an incremental treadmill-running test until voluntary exhaustion to determine maximal oxygen uptake and exercise intensity at maximal oxygen uptake. Subsequently, participants completed randomly 2 bouts of supramaximal treadmill-running at 110% exercise intensity at maximal oxygen uptake until exhaustion (placebo (6 g dextrose) or taurine (6 g) supplementation), separated by 1 week. MAODALT was determined using a single supramaximal effort by summating the contribution of the phosphagen and glycolytic pathways. When comparing the results of the supramaximal trials (i.e., placebo and taurine conditions) no differences were observed for high-intensity running TTE (237.70 ± 66.00 and 277.30 ± 40.64 s; p = 0.44) and MAODALT (55.77 ± 8.22 and 55.06 ± 7.89 mL·kg(-1); p = 0.61), which seem to indicate trivial and unclear differences using the magnitude-based inferences approach, respectively. In conclusion, acute 6 g taurine supplementation before exercise did not substantially improve high-intensity running performance and showed an unclear effect on MAODALT.

Does Physical Loading Affect The Speed and Accuracy of Tactical Decision-Making in Elite Junior Soccer Players?

PubMed

Frýbort, Pavel; Kokštejn, Jakub; Musálek, Martin; Süss, Vladimír

2016-06-01

A soccer player's capability to control and manage his behaviour in a game situation is a prerequisite, reflecting not only swift and accurate tactical decision-making, but also prompt implementation of a motor task during intermittent exercise conditions. The purpose of this study was to analyse the relationship between varying exercise intensity and the visual-motor response time and the accuracy of motor response in an offensive game situation in soccer. The participants (n = 42) were male, semi-professional, soccer players (M age 18.0 ± 0.9 years) and trained five times a week. Each player performed four different modes of exercise intensity on the treadmill (motor inactivity, aerobic, intermittent and anaerobic activity). After the end of each exercise, visual-motor response time and accuracy of motor response were assessed. Players' motion was captured by digital video camera. ANOVA indicated no significant difference (p = 0.090) in the accuracy of motor response between the four exercise intensity modes. Practical significance (Z-test = 0.31) was found in visual-motor response time between exercise with dominant involvement of aerobic metabolism, and intense intermittent exercise. A medium size effect (Z-test = 0.34) was also found in visual-motor response time between exercise with dominant involvement of aerobic metabolism and exercise with dominant involvement of anaerobic metabolism, which was confirmed by ANOVA (897.02 ± 57.46 vs. 940.95 ± 71.14; p = 0.002). The results showed that different modes of exercise intensity do not adversely affect the accuracy of motor responses; however, high-intensity exercise has a negative effect on visual-motor response time in comparison to moderate intensity exercise. Key pointsDifferent exercise intensity modes did not affect the accuracy of motor response.Anaerobic, highly intensive short-term exercise significantly decreased the visual-motor response time in comparison with aerobic exercise.Further research should focus on the assessment of VMRT from a player's real - field position view rather than a perspective view.

Ergogenic effects of caffeine and sodium bicarbonate supplementation on intermittent exercise performance preceded by intense arm cranking exercise.

PubMed

Marriott, Matthaus; Krustrup, Peter; Mohr, Magni

2015-01-01

Caffeine and sodium bicarbonate ingestion have been suggested to improve high-intensity intermittent exercise, but it is unclear if these ergogenic substances affect performance under provoked metabolic acidification. To study the effects of caffeine and sodium bicarbonate on intense intermittent exercise performance and metabolic markers under exercise-induced acidification, intense arm-cranking exercise was performed prior to intense intermittent running after intake of placebo, caffeine and sodium bicarbonate. Male team-sports athletes (n = 12) ingested sodium bicarbonate (NaHCO3; 0.4 g.kg(-1) b.w.), caffeine (CAF; 6 mg.kg(-1) b.w.) or placebo (PLA) on three different occasions. Thereafter, participants engaged in intense arm exercise prior to the Yo-Yo intermittent recovery test level-2 (Yo-Yo IR2). Heart rate, blood lactate and glucose as well as rating of perceived exertion (RPE) were determined during the protocol. CAF and NaHCO3 elicited a 14 and 23% improvement (P < 0.05), respectively, in Yo-Yo IR2 performance, post arm exercise compared to PLA. The NaHCO3 trial displayed higher [blood lactate] (P < 0.05) compared to CAF and PLA (10.5 ± 1.9 vs. 8.8 ± 1.7 and 7.7 ± 2.0 mmol.L(-1), respectively) after the Yo-Yo IR2. At exhaustion CAF demonstrated higher (P < 0.05) [blood glucose] compared to PLA and NaHCO3 (5.5 ± 0.7 vs. 4.2 ± 0.9 vs. 4.1 ± 0.9 mmol.L(-1), respectively). RPE was lower (P < 0.05) during the Yo-Yo IR2 test in the NaHCO3 trial in comparison to CAF and PLA, while no difference in heart rate was observed between trials. Caffeine and sodium bicarbonate administration improved Yo-Yo IR2 performance and lowered perceived exertion after intense arm cranking exercise, with greater overall effects of sodium bicarbonate intake.

Warm-up strategy and high-intensity endurance performance in trained cyclists.

PubMed

Christensen, Peter M; Bangsbo, Jens

2015-04-01

To evaluate the influence of warm-up exercise intensity and subsequent recovery on intense endurance performance, selected blood variables, and the oxygen-uptake (VO2) response. Twelve highly trained male cyclists (VO2max 72.4 ± 8.0 mL · min-1 · kg-1, incremental-test peak power output (iPPO) 432 ± 31 W; mean ± SD) performed 3 warm-up strategies lasting 20 min before a 4-min maximal-performance test (PT). Strategies consisted of moderate-intensity exercise (50%iPPO) followed by 6 min of recovery (MOD6) or progressive high-intensity exercise (10-100%iPPO and 2 × 20-s sprints) followed by recovery for 6 min (HI6) or 20 min (HI20). Before PT venous pH was lower (P < .001) in HI6 (7.27 ± 0.05) than in HI20 (7.34 ± 0.04) and MOD6 (7.35 ± 0.03). At the same time, differences (P < .001) existed for venous lactate in HI6 (8.2 ± 2.0 mmol/L), HI20 (5.1 ± 1.7 mmol/L), and MOD6 (1.4 ± 0.4 mmol/L), as well as for venous bicarbonate in HI6 (19.3 ± 2.6 mmol/L), HI20 (22.6 ± 2.3 mmol/L), and MOD6 (26.0 ± 1.4 mmol/L). Mean power in PT in HI6 (402 ± 38 W) tended to be lower (P = .11) than in HI20 (409 ± 34 W) and was lower (P = .007) than in MOD6 (416 ± 32 W). Total VO2 (15-120 s in PT) was higher in HI6 (8.18 ± 0.86 L) than in HI20 (7.85 ± 0.82 L, P = .008) and MOD6 (7.90 ± 0.74 L, P = .012). Warm-up exercise including race-pace and sprint intervals combined with short recovery can reduce subsequent performance in a 4-min maximal test in highly trained cyclists. Thus, a reduced time at high exercise intensity, a reduced intensity in the warm-up, or an extension of the recovery period after an intense warm-up is advocated.

Muscle activity in upper and lower rectus abdominus during abdominal exercises.

PubMed

Sarti, M A; Monfort, M; Fuster, M A; Villaplana, L A

1996-12-01

To compare the intensity of the upper versus lower rectus abdominis (RA) muscle activity provoked by each of two different abdominal exercises and to contrast the intensity of contraction elicited by two different abdominal exercises on each RA muscle portion. Nonrandomized control trial. Kinesiology laboratory in a university medicine faculty. Convenience sample of 33 healthy volunteers. Subjects who had practiced endurance or strength training activities (1.5 hours 3 days a week for 3 years) and those who had not accomplished that criterion comprised a high and a low physical activity group, respectively. Each of these two groups was divided by the ability to perform the exercises into two subgroups: correct and incorrect performers (cp, ic). Average surface iEMG was compared between upper and lower RA and on each muscle portion performing curl-up (CU) and posterior pelvic tilt (PT) exercises. The coefficient of variation, a two-way analysis of variance, and the t test were calculated. The upper RA showed significantly greater activity during performance of CU exercise by the cp subgroups of both high (t = 2.14302, 95%) and low (t = 2.35875, 95%) activity groups. Only the cp subgroup of the high activity group showed that PT was significantly more strenuous than CU exercise on lower RA (t = -2.06467, 95%). Among correct performers, CU produces greater activity on upper RA. For persons who have a high level of activity, PT is more strenuous than CU on lower RA. Among incorrect performers, either exercise indistinctly activates the muscle portions.

What influences acceptability and engagement with a high intensity exercise programme for people with stroke? A qualitative descriptive study.

PubMed

Signal, Nada; McPherson, Kathryn; Lewis, Gwyn; Kayes, Nicola; Saywell, Nicola; Mudge, Suzie; Taylor, Denise

2016-10-14

Intensity refers to the amount of effort or rate of work undertaken during exercise. People receiving rehabilitation after stroke frequently do not reach the moderate to high intensity exercise recommended to maximise gains. To explore the factors that influence the acceptability of, and engagement with, a high intensity group-based exercise programme for people with stroke. This qualitative descriptive study included 14 people with stroke who had completed a 12-week, high intensity group-based exercise rehabilitation programme. Semi-structured interviews were used to explore the acceptability of high intensity exercise and the barriers and facilitators to engagement. Interviews were recorded, transcribed and analysed using qualitative content analysis. The participants found high intensity exercise rehabilitation acceptable despite describing the exercise intensity as hard and reporting post-exercise fatigue. Participants accepted the fatigue as a normal response to exercise, and it did not appear to negatively influence engagement. The ease with which an individual engaged in high intensity exercise rehabilitation appeared to be mediated by inter-related factors, including: seeing progress, sourcing motivation, working hard, the people involved and the fit with the person and their life. Participants directly related the intensity of their effort to the gains that they made. In this study, people with stroke viewed training at higher intensities as a facilitator, not a barrier, to engagement in exercise rehabilitation. The findings may challenge assumptions about the influence of exercise intensity on engagement.

Cardiac Autonomic Responses during Exercise and Post-exercise Recovery Using Heart Rate Variability and Systolic Time Intervals-A Review.

PubMed

Michael, Scott; Graham, Kenneth S; Davis, Glen M

2017-01-01

Cardiac parasympathetic activity may be non-invasively investigated using heart rate variability (HRV), although HRV is not widely accepted to reflect sympathetic activity. Instead, cardiac sympathetic activity may be investigated using systolic time intervals (STI), such as the pre-ejection period. Although these autonomic indices are typically measured during rest, the "reactivity hypothesis" suggests that investigating responses to a stressor (e.g., exercise) may be a valuable monitoring approach in clinical and high-performance settings. However, when interpreting these indices it is important to consider how the exercise dose itself (i.e., intensity, duration, and modality) may influence the response. Therefore, the purpose of this investigation was to review the literature regarding how the exercise dosage influences these autonomic indices during exercise and acute post-exercise recovery. There are substantial methodological variations throughout the literature regarding HRV responses to exercise, in terms of exercise protocols and HRV analysis techniques. Exercise intensity is the primary factor influencing HRV, with a greater intensity eliciting a lower HRV during exercise up to moderate-high intensity, with minimal change observed as intensity is increased further. Post-exercise, a greater preceding intensity is associated with a slower HRV recovery, although the dose-response remains unclear. A longer exercise duration has been reported to elicit a lower HRV only during low-moderate intensity and when accompanied by cardiovascular drift, while a small number of studies have reported conflicting results regarding whether a longer duration delays HRV recovery. "Modality" has been defined multiple ways, with limited evidence suggesting exercise of a greater muscle mass and/or energy expenditure may delay HRV recovery. STI responses during exercise and recovery have seldom been reported, although limited data suggests that intensity is a key determining factor. Concurrent monitoring of HRV and STI may be a valuable non-invasive approach to investigate autonomic stress reactivity; however, this integrative approach has not yet been applied with regards to exercise stressors.

Cardiac Autonomic Responses during Exercise and Post-exercise Recovery Using Heart Rate Variability and Systolic Time Intervals—A Review

PubMed Central

Michael, Scott; Graham, Kenneth S.; Davis, Glen M.

2017-01-01

Cardiac parasympathetic activity may be non-invasively investigated using heart rate variability (HRV), although HRV is not widely accepted to reflect sympathetic activity. Instead, cardiac sympathetic activity may be investigated using systolic time intervals (STI), such as the pre-ejection period. Although these autonomic indices are typically measured during rest, the “reactivity hypothesis” suggests that investigating responses to a stressor (e.g., exercise) may be a valuable monitoring approach in clinical and high-performance settings. However, when interpreting these indices it is important to consider how the exercise dose itself (i.e., intensity, duration, and modality) may influence the response. Therefore, the purpose of this investigation was to review the literature regarding how the exercise dosage influences these autonomic indices during exercise and acute post-exercise recovery. There are substantial methodological variations throughout the literature regarding HRV responses to exercise, in terms of exercise protocols and HRV analysis techniques. Exercise intensity is the primary factor influencing HRV, with a greater intensity eliciting a lower HRV during exercise up to moderate-high intensity, with minimal change observed as intensity is increased further. Post-exercise, a greater preceding intensity is associated with a slower HRV recovery, although the dose-response remains unclear. A longer exercise duration has been reported to elicit a lower HRV only during low-moderate intensity and when accompanied by cardiovascular drift, while a small number of studies have reported conflicting results regarding whether a longer duration delays HRV recovery. “Modality” has been defined multiple ways, with limited evidence suggesting exercise of a greater muscle mass and/or energy expenditure may delay HRV recovery. STI responses during exercise and recovery have seldom been reported, although limited data suggests that intensity is a key determining factor. Concurrent monitoring of HRV and STI may be a valuable non-invasive approach to investigate autonomic stress reactivity; however, this integrative approach has not yet been applied with regards to exercise stressors. PMID:28611675

Muscle contractile characteristics: relationship to high-intensity exercise.

PubMed

Morris, Martyn G; Dawes, Helen; Howells, Ken; Scott, Oona M; Cramp, Mary; Izadi, Hooshang

2010-09-01

We investigated the relationship between muscle contractile characteristics, collected using percutaneous electrical stimulation, and high-intensity exercise performance. Seventeen participants performed a muscle performance test for the calculation of rate of torque development (RTD), rate of relaxation (RR(1/2)), rate of fatigue and fatigue resistance. On a second visit the participants completed a Wingate cycle ergometer test with peak power, mean power, fatigue index and fatigue rate calculated. The muscle fatigue index related significantly to the WAnT fatigue index and fatigue rate (p < 0.01). The change in rate of torque development (%DeltaRTD) was also related significantly to the fatigue rate (W/s) during the WAnT. Subjects displaying the greatest reduction in RTD had the greatest fatigue rate during the WAnT and greater fatigue during the electrical stimulation protocol. There were no significant relationships between peak (r 0.36; p > 0.01) or mean power (r -0.11, p > 0.01) with any of the muscle performance measures. These findings demonstrate that muscle contractile characteristics, elicited during standardised in vivo electrical stimulation, relate to performance during a Wingate anaerobic test. They suggest that muscle contraction characteristics play an important role in high-intensity exercise performance and indicate that electrical stimulation protocols can be a useful additional tool to explore muscle contraction characteristics in relation to exercise performance and trainability.

Six weeks of a polarized training-intensity distribution leads to greater physiological and performance adaptations than a threshold model in trained cyclists.

PubMed

Neal, Craig M; Hunter, Angus M; Brennan, Lorraine; O'Sullivan, Aifric; Hamilton, D Lee; De Vito, Giuseppe; Galloway, Stuart D R

2013-02-15

This study was undertaken to investigate physiological adaptation with two endurance-training periods differing in intensity distribution. In a randomized crossover fashion, separated by 4 wk of detraining, 12 male cyclists completed two 6-wk training periods: 1) a polarized model [6.4 (±1.4 SD) h/wk; 80%, 0%, and 20% of training time in low-, moderate-, and high-intensity zones, respectively]; and 2) a threshold model [7.5 (±2.0 SD) h/wk; 57%, 43%, and 0% training-intensity distribution]. Before and after each training period, following 2 days of diet and exercise control, fasted skeletal muscle biopsies were obtained for mitochondrial enzyme activity and monocarboxylate transporter (MCT) 1 and 4 expression, and morning first-void urine samples were collected for NMR spectroscopy-based metabolomics analysis. Endurance performance (40-km time trial), incremental exercise, peak power output (PPO), and high-intensity exercise capacity (95% maximal work rate to exhaustion) were also assessed. Endurance performance, PPOs, lactate threshold (LT), MCT4, and high-intensity exercise capacity all increased over both training periods. Improvements were greater following polarized rather than threshold for PPO [mean (±SE) change of 8 (±2)% vs. 3 (±1)%, P < 0.05], LT [9 (±3)% vs. 2 (±4)%, P < 0.05], and high-intensity exercise capacity [85 (±14)% vs. 37 (±14)%, P < 0.05]. No changes in mitochondrial enzyme activities or MCT1 were observed following training. A significant multilevel, partial least squares-discriminant analysis model was obtained for the threshold model but not the polarized model in the metabolomics analysis. A polarized training distribution results in greater systemic adaptation over 6 wk in already well-trained cyclists. Markers of muscle metabolic adaptation are largely unchanged, but metabolomics markers suggest different cellular metabolic stress that requires further investigation.

Intense physical exercise potentiates glucose inhibitory effect over food intake of male Wistar rats.

PubMed

Cavalcanti-de-Albuquerque, Joao Paulo; Kincheski, Grasielle Clotildes; Louzada, Ruy Andrade; Galina, Antônio; Pierucci, Anna Paola Trindade Rocha; Carvalho, Denise P

2018-06-12

What is the central question of this study? Physical exercise has emerged as a non-pharmacological treatment for obesity by promoting changes in energy balance. Despite the accumulated knowledge about exercise effects on energy expenditure, the central question of this study is to understand how an acute session of exercise might affect food intake of male Wistar rats. What is the main finding? The main finding of this work is that food intake in male Wistar rats is decreased in the first hour after physical exercise independent of the intensity. Moreover, high-intensity exercise potentiates the anorexic effect of peripheral glucose administration. Obesity has emerged as a critical metabolic disorder in modern society. An adequate lifestyle with good-oriented programs of diet and physical exercise (PE) can prevent or potentially even cure obesity. Additionally, PE might lead to weight loss by increasing energy expenditure and decreasing hunger perception. In this manuscript, we hypothesize that an acute exercise session with different intensities would potentiate the glucose inhibitory effects on food intake in male Wistar rats. Our data show that moderate- (MOD) or high-intensity (HIGH) PE significantly decreased food intake, although no changes in the expression of feeding-related neuropeptide in the arcuate nucleus of the hypothalamus were found. Exercised animals demonstrated a reduced glucose tolerance and increased blood insulin concentration. Intraperitoneal administration of glucose decreased food intake in control animals. In the animals submitted to MOD, the decrease in food intake promoted by glucose was similar to controls; however, an interaction was observed when glucose was injected in the HIGH group, in which food intake was significantly lower than the effect produced by glucose alone. A different pattern of expression was observed for the monocarboxylate transporter isoforms (MCT1, 2 and 4) and the 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKBP3) in the hypothalamus, which was dependent on the exercise intensity. In conclusion, PE decreases food intake independently of the intensity. However, an interaction between PE and the anorexic effect of glucose is only observed when a high-intensity exercise is performed. These data show an essential role of exercise intensity in the modulation of glucose inhibitory effect on food intake. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Short-term high-intensity interval training improves phosphocreatine recovery kinetics following moderate-intensity exercise in humans.

PubMed

Forbes, Sean C; Slade, Jill M; Meyer, Ronald A

2008-12-01

Previous studies have shown that high-intensity training improves biochemical markers of oxidative potential in skeletal muscle within a 2-week period. The purpose of this study was to examine the effect of short-term high-intensity interval training on the time constant () of phosphocreatine (PCr) recovery following moderate-intensity exercise, an in vivo measure of functional oxidative capacity. Seven healthy active subjects (age, 21 +/- 4 years; body mass, 69 +/- 11 kg) performed 6 sessions of 4-6 maximal-effort 30 s cycling intervals within a 2-week period, and 7 subjects (age, 24 +/- 5 years; body mass, 80 +/- 15 kg) served as controls. Prior to and following training, phosphorous-31 magnetic resonance spectroscopy (31P-MRS; GE 3T Excite System) was used to measure relative changes in high-energy phosphates and intracellular pH of the quadriceps muscles during gated dynamic leg-extension exercise (3 cycles of 90 s exercise and 5 min of rest). A monoexponential model was used to estimate the of PCr recovery. The of PCr recovery after leg-extension exercise was reduced by 14% with high-intensity interval training (pretraining, 43 +/- 14 s vs. post-training, 37 +/- 15 s; p < 0.05) with no change in the control group (44 +/- 12 s vs. 43 +/- 12 s, respectively; p > 0.05). These findings demonstrate that short-term high-intensity interval training is an effective means of increasing functional oxidative capacity in skeletal muscle.

Repeated high-intensity exercise modulates Ca(2+) sensitivity of human skeletal muscle fibers.

PubMed

Gejl, K D; Hvid, L G; Willis, S J; Andersson, E; Holmberg, H-C; Jensen, R; Frandsen, U; Hansen, J; Plomgaard, P; Ørtenblad, N

2016-05-01

The effects of short-term high-intensity exercise on single fiber contractile function in humans are unknown. Therefore, the purposes of this study were: (a) to access the acute effects of repeated high-intensity exercise on human single muscle fiber contractile function; and (b) to examine whether contractile function was affected by alterations in the redox balance. Eleven elite cross-country skiers performed four maximal bouts of 1300 m treadmill skiing with 45 min recovery. Contractile function of chemically skinned single fibers from triceps brachii was examined before the first and following the fourth sprint with respect to Ca(2+) sensitivity and maximal Ca(2+) -activated force. To investigate the oxidative effects of exercise on single fiber contractile function, a subset of fibers was incubated with dithiothreitol (DTT) before analysis. Ca(2+) sensitivity was enhanced by exercise in both MHC I (17%, P < 0.05) and MHC II (15%, P < 0.05) fibers. This potentiation was not present after incubation of fibers with DTT. Specific force of both MHC I and MHC II fibers was unaffected by exercise. In conclusion, repeated high-intensity exercise increased Ca(2+) sensitivity in both MHC I and MHC II fibers. This effect was not observed in a reducing environment indicative of an exercise-induced oxidation of the human contractile apparatus. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Diet composition and the performance of high-intensity exercise.

PubMed

Maughan, R J; Greenhaff, P L; Leiper, J B; Ball, D; Lambert, C P; Gleeson, M

1997-06-01

The crucial role of muscle glycogen as a fuel during prolonged exercise is well established, and the effects of acute changes in dietary carbohydrate intake on muscle glycogen content and on endurance capacity are equally well known. More recently, it has been recognized that diet can also affect the performance of high-intensity exercise of short (2-7 min) duration. If the muscle glycogen content is lowered by prolonged (1-1.5 h) exhausting cycle exercise, and is subsequently kept low for 3-4 days by consumption of a diet deficient in carbohydrate (< 5% of total energy intake), there is a dramatic (approximately 10-30%) reduction in exercise capacity during cycling sustainable for about 5 min. The same effect is observed if exercise is preceded by 3-4 days on a carbohydrate-restricted diet or by a 24 h total fast without prior depletion of the muscle glycogen. Consumption of a diet high in carbohydrate (70% of total energy intake from carbohydrate) for 3-4 days before exercise improves exercise capacity during high-intensity exercise, although this effect is less consistent. The blood lactate concentration is always lower at the point of fatigue after a diet low in carbohydrate and higher after a diet high in carbohydrate than after a normal diet. Even when the duration of the exercise task is kept constant, the blood lactate concentration is higher after exercise on a diet high in carbohydrate than on a diet low in carbohydrate. Consumption of a low-carbohydrate isoenergetic diet is achieved by an increased intake of protein and fat. A high-protein diet, particularly when combined with a low carbohydrate intake, results in metabolic acidosis, which ensues within 24 h and persists for at least 4 days. This appears to be the result of an increase in the circulating concentrations of strong organic acids, particularly free fatty acids and 3-hydroxybutyrate, together with an increase in the total plasma protein concentration. This acidosis, rather than any decrease in the muscle glycogen content, may be responsible for the reduced exercise capacity in high-intensity exercise; this may be due to a reduced rate of efflux of lactate and hydrogen ions from the working muscles. Alternatively, the accumulation of acetyl groups in the carbohydrate-deprived state may reduce substrate flux through the pyruvate dehydrogenase complex, thus reducing aerobic energy supply and accelerating the onset of fatigue.

Accuracy of Continuous Glucose Monitoring (CGM) during Continuous and High-Intensity Interval Exercise in Patients with Type 1 Diabetes Mellitus.

PubMed

Moser, Othmar; Mader, Julia K; Tschakert, Gerhard; Mueller, Alexander; Groeschl, Werner; Pieber, Thomas R; Koehler, Gerd; Messerschmidt, Janin; Hofmann, Peter

2016-08-10

Continuous exercise (CON) and high-intensity interval exercise (HIIE) can be safely performed with type 1 diabetes mellitus (T1DM). Additionally, continuous glucose monitoring (CGM) systems may serve as a tool to reduce the risk of exercise-induced hypoglycemia. It is unclear if CGM is accurate during CON and HIIE at different mean workloads. Seven T1DM patients performed CON and HIIE at 5% below (L) and above (M) the first lactate turn point (LTP₁), and 5% below the second lactate turn point (LTP₂) (H) on a cycle ergometer. Glucose was measured via CGM and in capillary blood (BG). Differences were found in comparison of CGM vs. BG in three out of the six tests (p < 0.05). In CON, bias and levels of agreement for L, M, and H were found at: 0.85 (-3.44, 5.15) mmol·L(-1), -0.45 (-3.95, 3.05) mmol·L(-1), -0.31 (-8.83, 8.20) mmol·L(-1) and at 1.17 (-2.06, 4.40) mmol·L(-1), 0.11 (-5.79, 6.01) mmol·L(-1), 1.48 (-2.60, 5.57) mmol·L(-1) in HIIE for the same intensities. Clinically-acceptable results (except for CON H) were found. CGM estimated BG to be clinically acceptable, except for CON H. Additionally, using CGM may increase avoidance of exercise-induced hypoglycemia, but usual BG control should be performed during intense exercise.

Effects of high-intensity exercise and protein supplement on muscle mass in ADL dependent older people with and without malnutrition: a randomized controlled trial.

PubMed

Carlsson, M; Littbrand, H; Gustafson, Y; Lundin-Olsson, L; Lindelöf, N; Rosendahl, E; Håglin, L

2011-08-01

Loss of muscle mass is common among old people living in institutions but trials that evaluate interventions aimed at increasing the muscle mass are lacking. Objective, participants and intervention: This randomized controlled trial was performed to evaluate the effect of a high-intensity functional exercise program and a timed protein-enriched drink on muscle mass in 177 people aged 65 to 99 with severe physical or cognitive impairments, and living in residential care facilities. Three-month high-intensity exercise was compared with a control activity and a protein-enriched drink was compared with a placebo drink. A bioelectrical impedance spectrometer (BIS) was used in the evaluation. The amount of muscle mass and body weight (BW) were followed-up at three and six months and analyzed in a 2 x 2 factorial ANCOVA, using the intention to treat principle, and controlling for baseline values. At 3-month follow-up there were no differences in muscle mass and BW between the exercise and the control group or between the protein and the placebo group. No interaction effects were seen between the exercise and nutritional intervention. Long-term negative effects on muscle mass and BW was seen in the exercise group at the 6-month follow-up. A three month high-intensity functional exercise program did not increase the amount of muscle mass and an intake of a protein-enriched drink immediately after the exercise did not induce any additional effect on muscle mass. There were negative long-term effects on muscle mass and BW, indicating that it is probably necessary to compensate for an increased energy demand when offering a high-intensity exercise program.

Acute Effect of Intermittent Exercise and Action-Based Video Game Breaks on Math Performance in Preadolescent Children.

PubMed

Block, Shannon S; Tooley, Trevor R; Nagy, Matthew R; O'Sullivan, Molly P; Robinson, Leah E; Colabianchi, Natalie; Hasson, Rebecca E

2018-02-27

The purpose of this study was to compare the acute effects of video game breaks and intermittent exercise breaks, performed at varying intensities, on math performance in preadolescent children. A total of 39 children (18 males and 21 females; aged 7-11 y) completed 4 experimental conditions in random order: 8 hours of sitting interrupted with 20 two-minute low-, moderate-, or high-intensity exercise breaks or 20 two-minute sedentary computer game breaks. The intensity of exercise breaks for the low-, moderate-, and high-intensity conditions corresponded with 25%, 50%, and 75% of heart rate reserve, respectively. Math performance was assessed 3 times throughout each condition day using a 90-second math test consisting of 40 single-digit addition and subtraction questions. There were no significant differences in percent change in math scores (correct answers out of attempted) by condition [low: -1.3 (0.8), moderate: 0.1 (1.3), high: -1.8 (0.7), and computer: -2.5 (0.8); P > .05]. There were significant differences in percent change in math scores over the course of the condition days with lower math scores reported at end-of-day test compared with midday test [-2.4 (0.5) vs -0.4 (0.3); P = .01]. There were no significant condition × time, time × age, condition × age, or condition × time × age interactions (all Ps > .05). Action-based video game and exercise breaks elicit the same level of math performance in children; however, time of day may impact this relationship. These findings may have important implications for instructional time in elementary classrooms.

Melatonin Supplementation Ameliorates Energy Charge and Oxidative Stress Induced by Acute Exercise in Rat Heart Tissue

PubMed Central

Cimen, Behzat; Uz, Ali; Cetin, Ihsan; Cimen, Leyla; Cetin, Aysun

2017-01-01

Background Regular physical exercises may help people to be more resistant to everyday problems; however, how acute and intense exercises affect the heart tissues functioning with maximum capacity and how melatonin changes the effect of acute and intense exercises are still not obvious. We aimed to comprehend whether melatonin intravenous injection supports the oxidative/antioxidative conditions and energy charge in heart tissues of rats exposed to acute swimming exercise. Methods Thirty Wistar-albino male rats were categorized into 3 groups with equal number of subjects. Control group performed no application, and acute intensive swimming exercise group were subjected to acute intensive swimming exercise for 30 minutes, and melatonin group were applied 25 mg/kg single dose melatonin administration prior to 30 minutes acute intensive swimming exercise. The levels of malondialdehyde (MDA), and superoxide dismutase, catalase and glutathione peroxidase activities were measured by spectrophotometric method; and the levels of 3-nitrotyrosine (3-NT) and energy charge were determined by a high performance liquid chromatography. Results Tissue MDA and 3-NT levels of the acute intensive exercise group were found to be higher than the control group. It was also found that the melatonin administration increased the energy charge and antioxidant activities, while decreased tissue MDA and 3-NT levels in heart tissues. Our results provide evidence for melatonin that can exert potent protective effects on oxidative stress and energy charge for heart tissues in acute swimming exercise. Conclusions These findings suggest that the direct beneficial effects of melatonin could be potentially applied on prevention of oxidative stress and energy deficit. PMID:28959107

Glucose response to exercise in the post-prandial period is independent of exercise intensity.

PubMed

Shambrook, P; Kingsley, M I; Wundersitz, D W; Xanthos, P D; Wyckelsma, V L; Gordon, B A

2018-03-01

This study investigated the acute glucose response to low-intensity, moderate-intensity, and high-intensity interval exercise compared to no-exercise in healthy insufficiently active males using a four-arm, randomized, crossover design. Ten males (age: 37.3 ± 7.3 years, BMI: 29.3 ± 6.5 kg·m -2 ) completed four 30-minute interventions at weekly intervals comprising low-intensity exercise (LIE) at ~35% V˙O 2 R, moderate-intensity exercise (MIE) at ~50% V˙O 2 R, high-intensity interval exercise (HIIE) at ~80% V˙O 2 R, and a no-exercise control. Participants performed cycle ergometer exercise 30 minutes after finishing breakfast. Glucose response was assessed using a continuous glucose monitor under free-living conditions with dietary intake replicated. A significant effect for intensity on energy expenditure was identified (P < .001) with similar energy cost in MIE (mean ± SD: 869 ± 148 kJ) and HIIE (806 ± 145 kJ), which were both greater than LIE (633 ± 129 kJ). The pattern of glucose response between the interventions over time was different (P = .02). Glucose was lower 25 minutes into each of the HIIE, MIE and LIE trials respectively (mean difference ± SD: -0.7 ± 1.1; -0.9 ± 1.1; -0.6 ± 0.9 mmol·L -1 ; P < .05) than in the no-exercise trial. Glucose response was not different between exercise intensities (P > .05). Twenty-four-hour AUC was not affected by exercise intensity (P = .75). There was a significant effect for exercise enjoyment (P = .02), with LIE (69 ± 4) preferred less than HIIE (mean ± SD: 84 ± 14; P = .02), MIE (73 ± 5; P = .03), and no-exercise (75 ± 4; P = .03). Exercise at any intensity 30 minutes after a meal affects glycemic regulation equally in insufficiently active males. Moderate to vigorous exercise intensities were preferred, and therefore, the exercise guidelines appear appropriate for the prevention of cardiometabolic disease. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Consumption of açai (Euterpe oleracea Mart.) functional beverage reduces muscle stress and improves effort tolerance in elite athletes: a randomized controlled intervention study.

PubMed

Carvalho-Peixoto, Jacqueline; Moura, Mirian Ribeiro Leite; Cunha, Felipe Amorim; Lollo, Pablo Christiano B; Monteiro, Walace David; Carvalho, Lucia Maria Jaeger de; Farinatti, Paulo de Tarso Veras

2015-07-01

The study analyzed the effect of an açai (Euterpe oleracea Mart.) functional beverage (AB) on muscle and oxidative stress markers, cardiorespiratory responses, perceived exertion, and time-to-exhaustion during maximal treadmill running. The beverage was developed as an ergogenic aid for athletes and contained 27.6 mg of anthocyanins per dose. Fourteen athletes performed 3 exercise tests: a ramp-incremental maximal exercise test and 2 maximal exercise bouts performed in 2 conditions (AB and without AB (control)) at 90% maximal oxygen uptake. Blood was collected at baseline and after maximal exercise in both conditions to determine biomarkers. AB increased time to exhaustion during short-term high-intensity exercise (mean difference: 69 s, 95% confidence interval = -296 s to 159 s, t = 2.2, p = 0.045), attenuating the metabolic stress induced by exercise (p < 0.05). AB also reduced perceived exertion and enhanced cardiorespiratory responses (p < 0.05). The AB may be a useful and practical ergogenic aid to enhance performance during high-intensity training.

Supplementation with a Polyphenol-Rich Extract, PerfLoad®, Improves Physical Performance during High-Intensity Exercise: A Randomized, Double Blind, Crossover Trial

PubMed Central

Cases, Julien; Romain, Cindy; Marín-Pagán, Cristian; Chung, Linda H.; Rubio-Pérez, José Miguel; Laurent, Caroline; Gaillet, Sylvie; Prost-Camus, Emmanuelle; Prost, Michel; Alcaraz, Pedro E.

2017-01-01

Workout capacity is energy-production driven. To produce peak metabolic power outputs, the organism predominantly relies more on anaerobic metabolism, but this undoubtedly has a negative and limiting impact on muscle function and performance. The aim of the study was to evaluate if an innovative polyphenol-based food supplement, PerfLoad®, was able to improve metabolic homeostasis and physical performance during high-intensity exercises under anaerobic conditions. The effect of a supplementation has been investigated on fifteen recreationally-active male athletes during a randomized, double-blind and crossover clinical investigation. The Wingate test, an inducer of an unbalanced metabolism associated to oxidative stress, was used to assess maximum anaerobic power during a high-intensity exercise on a cycle ergometer. Supplementation with PerfLoad® correlated with a significant increase in total power output (5%), maximal peak power output (3.7%), and average power developed (5%), without inducing more fatigue or greater heart rate. Instead, oxidative homeostasis was stabilized in supplemented subjects. Such results demonstrated that PerfLoad® is a natural and efficient solution capable of, similarly to training benefits, helping athletes to improve their physical performance, while balancing their metabolism and reducing exercise-induced oxidative stress. PMID:28441760

The effect of endothelin A and B receptor blockade on cutaneous vascular and sweating responses in young men during and following exercise in the heat.

PubMed

Fujii, Naoto; Singh, Maya S; Halili, Lyra; Louie, Jeffrey C; Kenny, Glen P

2016-12-01

During exercise, cutaneous vasodilation and sweating responses occur, whereas these responses rapidly decrease during postexercise recovery. We hypothesized that the activation of endothelin A (ET A ) receptors, but not endothelin B (ET B ) receptors, attenuate cutaneous vasodilation during high-intensity exercise and contribute to the subsequent postexercise suppression of cutaneous vasodilation. We also hypothesized that both receptors increase sweating during and following high-intensity exercise. Eleven men (24 ± 4 yr) performed an intermittent cycling protocol consisting of two 30-min bouts of moderate- (40% V̇o 2peak ) and high-intensity (75% V̇o 2peak ) exercise in the heat (35°C), each separated by a 20- and 40-min recovery period, respectively. Cutaneous vascular conductance (CVC) and sweat rate were evaluated at four intradermal microdialysis skin sites: 1) lactated Ringer (control), 2) 500 nM BQ123 (a selective ET A receptor blocker), 3) 300 nM BQ788 (a selective ET B receptor blocker), or 4) a combination of BQ123 + BQ788. There were no between-site differences in CVC during each exercise bout (all P > 0.05); however, CVC following high-intensity exercise was greater at BQ123 (56 ± 9%max) and BQ123 + BQ788 (55 ± 14%max) sites relative to the control site (43 ± 12%max) (all P ≤ 0.05). Sweat rate did not differ between sites throughout the protocol (all P > 0.05). We show that neither ET A nor ET B receptors modulate cutaneous vasodilation and sweating responses during and following moderate- and high-intensity exercise in the heat, with the exception that ET A receptors may partly contribute to the suppression of cutaneous vasodilation following high-intensity exercise. Copyright © 2016 the American Physiological Society.

High intensity exercise or conventional exercise for patients with rheumatoid arthritis? Outcome expectations of patients, rheumatologists, and physiotherapists

PubMed Central

Munneke, M; de Jong, Z; Zwinderman, A; Ronday, H; van den Ende, C H M; Vliet, V; Hazes, J

2004-01-01

Objective: To examine the outcome expectations of RA patients, rheumatologists, and physiotherapists regarding high intensity exercise programmes compared with conventional exercise programmes. Methods: An exercise outcome expectations questionnaire was administered to 807 RA patients, 153 rheumatologists, and 624 physiotherapists. The questionnaire consisted of four statements regarding positive and negative outcomes of high intensity exercise programmes and four similar statements for conventional exercise programmes. A total expectation score for both conventional and high intensity exercise was calculated, ranging from –2 (very negative expectation) to 2 (very positive expectation). Results: The questionnaire was returned by 662 RA patients (82%), 132 rheumatologists (86%), and 467 physiotherapists (75%). The mean (95% confidence interval) scores for high intensity exercise programmes were 0.30 (0.25 to 0.34), 0.68 (0.62 to 0.74), and –0.06 (–0.15 to 0.02), and for conventional exercise programmes were 0.99 (0.96 to 1.02), 1.13 (1.09 to 1.17), and 1.27 (1.21 to 1.34) for RA patients, rheumatologists, and physiotherapists, respectively. In all three respondent groups, the outcome expectations of high intensity exercise were significantly less positive than those of conventional exercise programme. Conclusions: Despite the existing evidence regarding the effectiveness and safety of high intensity exercise programmes, RA patients, rheumatologists, and physiotherapists have more positive expectations of conventional exercise programmes than of high intensity exercise programmes. Physiotherapists were the least positive about outcomes of high intensity exercise programmes while rheumatologists were the most positive. To help the implementation of new insights in the effectiveness of physical therapy modalities in rheumatology, the need for continuous education of patients, rheumatologists and physiotherapists is emphasised. PMID:15194575

Physiological intensity profile, exercise load and performance predictors of a 65-km mountain ultra-marathon.

PubMed

Fornasiero, Alessandro; Savoldelli, Aldo; Fruet, Damiano; Boccia, Gennaro; Pellegrini, Barbara; Schena, Federico

2018-06-01

The aims of the study were to describe the physiological profile of a 65-km (4000-m cumulative elevation gain) running mountain ultra-marathon (MUM) and to identify predictors of MUM performance. Twenty-three amateur trail-runners performed anthropometric evaluations and an uphill graded exercise test (GXT) for VO 2max, ventilatory thresholds (VTs), power outputs (PMax, PVTs) and heart rate response (HRmax, HR@VTs). Heart rate (HR) was monitored during the race and intensity was expressed as: Zone I (VT2) for exercise load calculation (training impulse, TRIMP). Mean race intensity was 77.1%±4.4% of HRmax distributed as: 85.7%±19.4% Zone I, 13.9%±18.6% Zone II, 0.4%±0.9% Zone III. Exercise load was 766±110 TRIMP units. Race time (11.8±1.6h) was negatively correlated with VO 2max (r = -0.66, P <0.001) and PMax (r = -0.73, P <0.001), resulting these variables determinant in predicting MUM performance, whereas exercise thresholds did not improve performance prediction. Laboratory variables explained only 59% of race time variance, underlining the multi-factorial character of MUM performance. Our results support the idea that VT1 represents a boundary of tolerable intensity in this kind of events, where exercise load is extremely high. This information can be helpful in identifying optimal pacing strategies to complete such extremely demanding MUMs.

Drug abusers have impaired cerebral oxygenation and cognition during exercise

PubMed Central

Soares Rachetti, Vanessa; Quirino Alves da Silva, Weslley; Aranha Rego Cabral, Daniel; Gomes da Silva Machado, Daniel; Caldas Costa, Eduardo; Forti, Rodrigo Menezes; Mesquita, Rickson Coelho; Elsangedy, Hassan Mohamed; Hideki Okano, Alexandre; Bodnariuc Fontes, Eduardo

2017-01-01

Background Individuals with Substance Use Disorder (SUD) have lower baseline metabolic activity of the prefrontal cortex (PFC) associated with impairment of cognitive functions in decision-making and inhibitory control. Aerobic exercise has shown to improve PFC function and cognitive performance, however, its effects on SUD individuals remain unclear. Purpose To verify the cognitive performance and oxygenation of the PFC during an incremental exercise in SUD individuals. Methods Fourteen individuals under SUD treatment performed a maximum graded exercise test on a cycle ergometer with continuous measurements of oxygen consumption, PFC oxygenation, and inhibitory control (Stroop test) every two minutes of exercise at different intensities. Fifteen non-SUD individuals performed the same protocol and were used as control group. Results Exercise increased oxyhemoglobin (O2Hb) and total hemoglobin (tHb) by 9% and 7%, respectively. However, when compared to a non-SUD group, this increase was lower at high intensities (p<0.001), and the inhibitory cognitive control was lower at rest and during exercise (p<0.007). In addition, PFC hemodynamics during exercise was inversely correlated with inhibitory cognitive performance (reaction time) (r = -0.62, p = 0.001), and a lower craving perception for the specific abused substance (p = 0.0189) was reported immediately after exercise. Conclusion Despite SUD individuals having their PFC cerebral oxygenation increased during exercise, they presented lower cognition and oxygenation when compared to controls, especially at elevated intensities. These results may reinforce the role of exercise as an adjuvant treatment to improve PFC function and cognitive control in individuals with SUD. PMID:29125875

Validation of Heart Rate Monitor Polar RS800 for Heart Rate Variability Analysis During Exercise.

PubMed

Hernando, David; Garatachea, Nuria; Almeida, Rute; Casajús, Jose A; Bailón, Raquel

2018-03-01

Hernando, D, Garatachea, N, Almeida, R, Casajús, JA, and Bailón, R. Validation of heart rate monitor Polar RS800 for heart rate variability analysis during exercise. J Strength Cond Res 32(3): 716-725, 2018-Heart rate variability (HRV) analysis during exercise is an interesting noninvasive tool to measure the cardiovascular response to the stress of exercise. Wearable heart rate monitors are a comfortable option to measure interbeat (RR) intervals while doing physical activities. It is necessary to evaluate the agreement between HRV parameters derived from the RR series recorded by wearable devices and those derived from an electrocardiogram (ECG) during dynamic exercise of low to high intensity. Twenty-three male volunteers performed an exercise stress test on a cycle ergometer. Subjects wore a Polar RS800 device, whereas ECG was also recorded simultaneously to extract the reference RR intervals. A time-frequency spectral analysis was performed to extract the instantaneous mean heart rate (HRM), and the power of low-frequency (PLF) and high-frequency (PHF) components, the latter centered on the respiratory frequency. Analysis was done in intervals of different exercise intensity based on oxygen consumption. Linear correlation, reliability, and agreement were computed in each interval. The agreement between the RR series obtained from the Polar device and from the ECG is high throughout the whole test although the shorter the RR is, the more differences there are. Both methods are interchangeable when analyzing HRV at rest. At high exercise intensity, HRM and PLF still presented a high correlation (ρ > 0.8) and excellent reliability and agreement indices (above 0.9). However, the PHF measurements from the Polar showed reliability and agreement coefficients around 0.5 or lower when the level of the exercise increases (for levels of O2 above 60%).

The influence of whole-body vs. torso pre-cooling on physiological strain and performance of high-intensity exercise in the heat.

PubMed

Sleivert, G G; Cotter, J D; Roberts, W S; Febbraio, M A

2001-04-01

Little research has been reported examining the effects of pre-cooling on high-intensity exercise performance, particularly when combined with strategies to keep the working muscle warm. This study used nine active males to determine the effects of pre-cooling the torso and thighs (LC), pre-cooling the torso (ice-vest in 3 degrees C air) while keeping the thighs warm (LW), or no cooling (CON: 31 degrees C air), on physiological strain and high-intensity (45-s) exercise performance (33 degrees C, 60% rh). Furthermore, we sought to determine whether performance after pre-cooling was influenced by a short exercise warm-up. The 45-s test was performed at different (P<0.05) mean core temperature [(rectal+oesophageal)/2] [CON: 37.3+/-0.3 (S.D.), LW: 37.1+/-0.3, LC: 36.8+/-0.4 degrees C] and mean skin temperature (CON: 34.6+/-0.6, LW: 29.0+/-1.0, LC: 27.2+/-1.2 degrees C) between all conditions. Forearm blood flow prior to exercise was also lower in LC (3.1+/-2.0 ml 100 ml tissue(-1) x min(-1)) than CON (8.2+/-2.5, P=0.01) but not LW (4.3+/-2.6, P=0.46). After an exercise warm-up, muscle temperature (Tm) was not significantly different between conditions (CON: 37.3+/-1.5, LW: 37.3+/-1.2, LC: 36.6+/-0.7 degrees C, P=0.16) but when warm-up was excluded, T(m) was lower in LC (34.5+/-1.9 degrees C, P=0.02) than in CON (37.3+/-1.0) and LW (37.1+/-0.9). Even when a warm-up was performed, torso+thigh pre-cooling decreased both peak (-3.4+/-3.8%, P=0.04) and mean power output (-4.1+/-3.8%, P=0.01) relative to the control, but this effect was markedly larger when warm-up was excluded (peak power -7.7+/-2.5%, P=0.01; mean power -7.6+/-1.2%, P=0.01). Torso-only pre-cooling did not reduce peak or mean power, either with or without warm-up. These data indicate that pre-cooling does not improve 45-s high-intensity exercise performance, and can impair performance if the working muscles are cooled. A short exercise warm-up largely removes any detrimental effects of a cold muscle on performance by increasing Tm.

Regulation of Muscle Glycogen Metabolism during Exercise: Implications for Endurance Performance and Training Adaptations

PubMed Central

Hearris, Mark A.; Hammond, Kelly M.; Fell, J. Marc; Morton, James P.

2018-01-01

Since the introduction of the muscle biopsy technique in the late 1960s, our understanding of the regulation of muscle glycogen storage and metabolism has advanced considerably. Muscle glycogenolysis and rates of carbohydrate (CHO) oxidation are affected by factors such as exercise intensity, duration, training status and substrate availability. Such changes to the global exercise stimulus exert regulatory effects on key enzymes and transport proteins via both hormonal control and local allosteric regulation. Given the well-documented effects of high CHO availability on promoting exercise performance, elite endurance athletes are typically advised to ensure high CHO availability before, during and after high-intensity training sessions or competition. Nonetheless, in recognition that the glycogen granule is more than a simple fuel store, it is now also accepted that glycogen is a potent regulator of the molecular cell signaling pathways that regulate the oxidative phenotype. Accordingly, the concept of deliberately training with low CHO availability has now gained increased popularity amongst athletic circles. In this review, we present an overview of the regulatory control of CHO metabolism during exercise (with a specific emphasis on muscle glycogen utilization) in order to discuss the effects of both high and low CHO availability on modulating exercise performance and training adaptations, respectively. PMID:29498691

The Effects of Different Passive Static Stretching Intensities on Recovery from Unaccustomed Eccentric Exercise - A Randomized Controlled Trial.

PubMed

Apostolopoulos, Nikos C; Lahart, Ian M; Plyley, Michael J; Taunton, Jack; Nevill, Alan M; Koutedakis, Yiannis; Wyon, Matthew; Metsios, George S

2018-03-12

Effects of passive static stretching intensity on recovery from unaccustomed eccentric exercise of right knee extensors was investigated in 30 recreationally active males randomly allocated into three groups: high-intensity (70-80% maximum perceived stretch), low-intensity (30-40% maximum perceived stretch), and control. Both stretching groups performed 3 sets of passive static stretching exercises of 60s each for hamstrings, hip flexors, and quadriceps, over 3 consecutive days, post-unaccustomed eccentric exercise. Muscle function (eccentric and isometric peak torque) and blood biomarkers (CK and CRP) were measured before (baseline) and after (24, 48, and 72h) unaccustomed eccentric exercise. Perceived muscle soreness scores were collected immediately (time 0), and after 24, 48, and 72h post-exercise. Statistical time x condition interactions observed only for eccentric peak torque (p=.008). Magnitude-based inference analyses revealed low-intensity stretching had most likely, very likely, or likely beneficial effects on perceived muscle soreness (48-72h and 0-72h) and eccentric peak torque (baseline-24h and baseline-72h), compared with high-intensity stretching. Compared with control, low-intensity stretching had very likely or likely beneficial effects on perceived muscle soreness (0-24h and 0-72h), eccentric peak torque (baseline-48h and baseline-72h), and isometric peak torque (baseline-72h). High-intensity stretching had likely beneficial effects on eccentric peak torque (baseline-48h), but likely harmful effects eccentric peak torque (baseline-24h) and CK (baseline-48h and baseline-72h), compared with control. Therefore, low-intensity stretching is likely to result in small-to-moderate beneficial effects on perceived muscle soreness and recovery of muscle function post-unaccustomed eccentric exercise, but not markers of muscle damage and inflammation, compared with high-intensity or no stretching.

Locomotor Muscle Fatigue Does Not Alter Oxygen Uptake Kinetics during High-Intensity Exercise.

PubMed

Hopker, James G; Caporaso, Giuseppe; Azzalin, Andrea; Carpenter, Roger; Marcora, Samuele M

2016-01-01

The [Formula: see text] slow component ([Formula: see text]) that develops during high-intensity aerobic exercise is thought to be strongly associated with locomotor muscle fatigue. We sought to experimentally test this hypothesis by pre-fatiguing the locomotor muscles used during subsequent high-intensity cycling exercise. Over two separate visits, eight healthy male participants were asked to either perform a non-metabolically stressful 100 intermittent drop-jumps protocol (pre-fatigue condition) or rest for 33 min (control condition) according to a random and counterbalanced order. Locomotor muscle fatigue was quantified with 6-s maximal sprints at a fixed pedaling cadence of 90 rev·min -1 . Oxygen kinetics and other responses (heart rate, capillary blood lactate concentration and rating of perceived exertion, RPE) were measured during two subsequent bouts of 6 min cycling exercise at 50% of the delta between the lactate threshold and [Formula: see text] determined during a preliminary incremental exercise test. All tests were performed on the same cycle ergometer. Despite significant locomotor muscle fatigue ( P = 0.03), the [Formula: see text] was not significantly different between the pre-fatigue (464 ± 301 mL·min -1 ) and the control (556 ± 223 mL·min -1 ) condition ( P = 0.50). Blood lactate response was not significantly different between conditions ( P = 0.48) but RPE was significantly higher following the pre-fatiguing exercise protocol compared with the control condition ( P < 0.01) suggesting higher muscle recruitment. These results demonstrate experimentally that locomotor muscle fatigue does not significantly alter the [Formula: see text] kinetic response to high intensity aerobic exercise, and challenge the hypothesis that the [Formula: see text] is strongly associated with locomotor muscle fatigue.

Locomotor Muscle Fatigue Does Not Alter Oxygen Uptake Kinetics during High-Intensity Exercise

PubMed Central

Hopker, James G.; Caporaso, Giuseppe; Azzalin, Andrea; Carpenter, Roger; Marcora, Samuele M.

2016-01-01

The V˙O2 slow component (V˙O2sc) that develops during high-intensity aerobic exercise is thought to be strongly associated with locomotor muscle fatigue. We sought to experimentally test this hypothesis by pre-fatiguing the locomotor muscles used during subsequent high-intensity cycling exercise. Over two separate visits, eight healthy male participants were asked to either perform a non-metabolically stressful 100 intermittent drop-jumps protocol (pre-fatigue condition) or rest for 33 min (control condition) according to a random and counterbalanced order. Locomotor muscle fatigue was quantified with 6-s maximal sprints at a fixed pedaling cadence of 90 rev·min−1. Oxygen kinetics and other responses (heart rate, capillary blood lactate concentration and rating of perceived exertion, RPE) were measured during two subsequent bouts of 6 min cycling exercise at 50% of the delta between the lactate threshold and V˙O2max determined during a preliminary incremental exercise test. All tests were performed on the same cycle ergometer. Despite significant locomotor muscle fatigue (P = 0.03), the V˙O2sc was not significantly different between the pre-fatigue (464 ± 301 mL·min−1) and the control (556 ± 223 mL·min−1) condition (P = 0.50). Blood lactate response was not significantly different between conditions (P = 0.48) but RPE was significantly higher following the pre-fatiguing exercise protocol compared with the control condition (P < 0.01) suggesting higher muscle recruitment. These results demonstrate experimentally that locomotor muscle fatigue does not significantly alter the V˙O2 kinetic response to high intensity aerobic exercise, and challenge the hypothesis that the V˙O2sc is strongly associated with locomotor muscle fatigue. PMID:27790156

Effects of myofascial release after high-intensity exercise: a randomized clinical trial.

PubMed

Arroyo-Morales, Manuel; Olea, Nicolas; Martinez, Manuel; Moreno-Lorenzo, Carmen; Díaz-Rodríguez, Lourdes; Hidalgo-Lozano, Amparo

2008-03-01

The usefulness of massage as a recovery method after high-intensity exercise has yet to be established. We aimed to investigate the effects of whole-body massage on heart rate variability (HRV) and blood pressure (BP) after repeated high-intensity cycling exercise under controlled and standardized pretest conditions. The study included 62 healthy active individuals. After baseline measurements, the subjects performed standardized warm-up exercises followed by three 30-second Wingate tests. After completing the exercise protocol, the subjects were randomly assigned to a massage (myofascial release) or placebo (sham treatment with disconnected ultrasound and magnetotherapy equipment) group for a 40-minute recovery period. Holter recording and BP measurements were taken after exercise protocol and after the intervention. After the exercise protocol, both groups showed a significant decrease in normal-to-normal interval, HRV index, diastolic BP (P > .001), and low-frequency domain values (P = .006). After the recovery period, HRV index (P = .42) and high-frequency (HF) (P = .94) values were similar to baseline levels in the massage group, whereas the HRV index tended (P = .05) to be lower and the HF was significantly (P < .01) lower vs baseline values in the placebo group, which also showed a tendency (P = .06) for HF to be lower than after the exercise. Likewise, diastolic BP returned to baseline levels in the massage group (P = .45) but remained lower in the placebo group (P = .02). Myofascial release massage favors the recovery of HRV and diastolic BP after high-intensity exercise (3 Wingate tests) to preexercise levels.

Dose-Response of High-Intensity Training (HIT) on Atheroprotective miRNA-126 Levels

PubMed Central

Schmitz, Boris; Schelleckes, Katrin; Nedele, Johanna; Thorwesten, Lothar; Klose, Andreas; Lenders, Malte; Krüger, Michael; Brand, Eva; Brand, Stefan-Martin

2017-01-01

Aim: MicroRNA-126 (miR-126) exerts beneficial effects on vascular integrity, angiogenesis, and atherosclerotic plaque stability. The purpose of this investigation was to analyze the dose-response relationship of high-intensity interval training (HIIT) on miR-126-3p and -5p levels. Methods: Sixty-one moderately trained individuals (females = 31 [50.8%]; 22.0 ± 1.84 years) were consecutively recruited and allocated into three matched groups using exercise capacity. During a 4-week intervention a HIIT group performed three exercise sessions/week of 4 × 30 s at maximum speed (all-out), a progressive HIIT (proHIIT) group performed three exercise sessions/week of 4 × 30 s at maximum speed (all-out) with one extra session every week (up to 7 × 30 s) and a low-intensity training (LIT) control group performed three exercise sessions/week for 25 min <75% of maximum heart rate. Exercise miR-126-3p/-5p plasma levels were determined using capillary blood from earlobes. Results: No exercise-induced increase in miR-126 levels was detected at baseline, neither in the LIT (after 25 min low-intensity running) nor the HIIT groups (after 4 min of high-intensity running). After the intervention, the LIT group presented an increase in miR-126-3p, while in the HIIT group, miR-126-3p levels were still reduced (all p < 0.05). An increase for both, miR-126-3p and -5p levels (all p < 0.05, pre- vs. during and post-exercise) was detected in the proHIIT group. Between group analysis revealed that miR-126-3p levels after LIT and proHIIT increased by 2.12 ± 2.55 and 1.24 ± 2.46 units (all p < 0.01), respectively, compared to HIIT (−1.05 ± 2.6 units). Conclusions: LIT and proHIIT may be performed to increase individual miR-126 levels. HIIT without progression was less effective in increasing miR-126. PMID:28611681

Dose-Response of High-Intensity Training (HIT) on Atheroprotective miRNA-126 Levels.

PubMed

Schmitz, Boris; Schelleckes, Katrin; Nedele, Johanna; Thorwesten, Lothar; Klose, Andreas; Lenders, Malte; Krüger, Michael; Brand, Eva; Brand, Stefan-Martin

2017-01-01

Aim: MicroRNA-126 (miR-126) exerts beneficial effects on vascular integrity, angiogenesis, and atherosclerotic plaque stability. The purpose of this investigation was to analyze the dose-response relationship of high-intensity interval training (HIIT) on miR-126-3p and -5p levels. Methods: Sixty-one moderately trained individuals (females = 31 [50.8%]; 22.0 ± 1.84 years) were consecutively recruited and allocated into three matched groups using exercise capacity. During a 4-week intervention a HIIT group performed three exercise sessions/week of 4 × 30 s at maximum speed (all-out), a progressive HIIT (proHIIT) group performed three exercise sessions/week of 4 × 30 s at maximum speed (all-out) with one extra session every week (up to 7 × 30 s) and a low-intensity training (LIT) control group performed three exercise sessions/week for 25 min <75% of maximum heart rate. Exercise miR-126-3p/-5p plasma levels were determined using capillary blood from earlobes. Results: No exercise-induced increase in miR-126 levels was detected at baseline, neither in the LIT (after 25 min low-intensity running) nor the HIIT groups (after 4 min of high-intensity running). After the intervention, the LIT group presented an increase in miR-126-3p, while in the HIIT group, miR-126-3p levels were still reduced (all p < 0.05). An increase for both, miR-126-3p and -5p levels (all p < 0.05, pre- vs. during and post-exercise) was detected in the proHIIT group. Between group analysis revealed that miR-126-3p levels after LIT and proHIIT increased by 2.12 ± 2.55 and 1.24 ± 2.46 units (all p < 0.01), respectively, compared to HIIT (-1.05 ± 2.6 units). Conclusions: LIT and proHIIT may be performed to increase individual miR-126 levels. HIIT without progression was less effective in increasing miR-126.

Much potential but many unanswered questions for high-intensity intermittent exercise training for patients with heart failure.

PubMed

Pinkstaff, Sherry O

2015-01-01

There is a robust trove of scientific studies that support the positive physical and mental health benefits associated with aerobic exercise for healthy individuals. These recommendations suggest that more vigorous exercise can be performed on fewer days for the same benefit. High-intensity intermittent exercise (HIIE) training has begun to show promise. HIIE seems safe and improves physiology, quality of life, and functional capacity. This review defines HIIE, discusses its physiologic benefit for patients with heart failure, outlines the studies that have been conducted to date, and places it in the context of the current clinical environment of exercise training for these patients. Copyright © 2015 Elsevier Inc. All rights reserved.

Does Physical Loading Affect The Speed and Accuracy of Tactical Decision-Making in Elite Junior Soccer Players?

PubMed Central

Frýbort, Pavel; Kokštejn, Jakub; Musálek, Martin; Süss, Vladimír

2016-01-01

A soccer player’s capability to control and manage his behaviour in a game situation is a prerequisite, reflecting not only swift and accurate tactical decision-making, but also prompt implementation of a motor task during intermittent exercise conditions. The purpose of this study was to analyse the relationship between varying exercise intensity and the visual-motor response time and the accuracy of motor response in an offensive game situation in soccer. The participants (n = 42) were male, semi-professional, soccer players (M age 18.0 ± 0.9 years) and trained five times a week. Each player performed four different modes of exercise intensity on the treadmill (motor inactivity, aerobic, intermittent and anaerobic activity). After the end of each exercise, visual-motor response time and accuracy of motor response were assessed. Players’ motion was captured by digital video camera. ANOVA indicated no significant difference (p = 0.090) in the accuracy of motor response between the four exercise intensity modes. Practical significance (Z-test = 0.31) was found in visual-motor response time between exercise with dominant involvement of aerobic metabolism, and intense intermittent exercise. A medium size effect (Z-test = 0.34) was also found in visual-motor response time between exercise with dominant involvement of aerobic metabolism and exercise with dominant involvement of anaerobic metabolism, which was confirmed by ANOVA (897.02 ± 57.46 vs. 940.95 ± 71.14; p = 0.002). The results showed that different modes of exercise intensity do not adversely affect the accuracy of motor responses; however, high-intensity exercise has a negative effect on visual-motor response time in comparison to moderate intensity exercise. Key points Different exercise intensity modes did not affect the accuracy of motor response. Anaerobic, highly intensive short-term exercise significantly decreased the visual-motor response time in comparison with aerobic exercise. Further research should focus on the assessment of VMRT from a player’s real - field position view rather than a perspective view. PMID:27274671

Can previously sedentary females use the feeling scale to regulate exercise intensity in a gym environment? an observational study.

PubMed

Hamlyn-Williams, Charlotte C; Tempest, Gavin; Coombs, Sarah; Parfitt, Gaynor

2015-01-01

Recent research suggests that the Feeling Scale (FS) can be used as a method of exercise intensity regulation to maintain a positive affective response during exercise. However, research to date has been carried out in laboratories and is not representative of natural exercise environments. The purpose of this study was to evaluate whether sedentary women can self-regulate their exercise intensity using the FS to experience positive affective responses in a gym environment using their own choice of exercise mode; cycling or treadmill. Fourteen females (24.9 years ± 5.2; height 166.7 ± 5.7 cm; mass 66.3 ± 13.4 kg; BMI 24.1 ± 5.5)) completed a submaximal exercise test and each individual's ventilatory threshold ([Formula: see text]) was identified. Following this, three 20 min gym-based exercise trials, either on a bike or treadmill were performed at an intensity that was self-selected and perceived to correspond to the FS value of +3 (good). Oxygen uptake, heart rate (HR) and ratings of perceived exertion (RPE) were measured during exercise at the participants chosen intensity. Results indicated that on average participants worked close to their [Formula: see text] and increased their exercise intensity during the 20-min session. Participants worked physiologically harder during cycling exercise. Consistency of oxygen uptake, HR and RPE across the exercise trials was high. The data indicate that previously sedentary women can use the FS in an ecological setting to regulate their exercise intensity and that regulating intensity to feel 'good' should lead to individuals exercising at an intensity that would result in cardiovascular gains if maintained.

High-intensity exercise training induces morphological and biochemical changes in skeletal muscles.

PubMed

Toti, L; Bartalucci, A; Ferrucci, M; Fulceri, F; Lazzeri, G; Lenzi, P; Soldani, P; Gobbi, P; La Torre, A; Gesi, M

2013-12-01

IN THE PRESENT STUDY WE INVESTIGATED THE EFFECT OF TWO DIFFERENT EXERCISE PROTOCOLS ON FIBRE COMPOSITION AND METABOLISM OF TWO SPECIFIC MUSCLES OF MICE: the quadriceps and the gastrocnemius. Mice were run daily on a motorized treadmill, at a velocity corresponding to 60% or 90% of the maximal running velocity. Blood lactate and body weight were measured during exercise training. We found that at the end of training the body weight significantly increased in high-intensity exercise mice compared to the control group (P=0.0268), whereas it decreased in low-intensity exercise mice compared to controls (P=0.30). In contrast, the food intake was greater in both trained mice compared to controls (P < 0.0001 and P < 0.0001 for low-intensity and high-intensity exercise mice, respectively). These effects were accompanied by a progressive reduction in blood lactate levels at the end of training in both the exercised mice compared with controls (P=0.03 and P < 0.0001 for low-intensity and high-intensity exercise mice, respectively); in particular, blood lactate levels after high-intensity exercise were significantly lower than those measured in low-intensity exercise mice (P=0.0044). Immunoblotting analysis demonstrated that high-intensity exercise training produced a significant increase in the expression of mitochondrial enzymes contained within gastrocnemius and quadriceps muscles. These changes were associated with an increase in the amount of slow fibres in both these muscles of high-intensity exercise mice, as revealed by the counts of slow fibres stained with specific antibodies (P < 0.0001 for the gastrocnemius; P=0.0002 for the quadriceps). Our results demonstrate that high-intensity exercise, in addition to metabolic changes consisting of a decrease in blood lactate and body weight, induces an increase in the mitochondrial enzymes and slow fibres in different skeletal muscles of mice, which indicates an exercise-induced increase in the aerobic metabolism.

Muscle and intensity based hamstring exercise classification in elite female track and field athletes: implications for exercise selection during rehabilitation.

PubMed

Tsaklis, Panagiotis; Malliaropoulos, Nikos; Mendiguchia, Jurdan; Korakakis, Vasileios; Tsapralis, Kyriakos; Pyne, Debasish; Malliaras, Peter

2015-01-01

Hamstring injuries are common in many sports, including track and field. Strains occur in different parts of the hamstring muscle but very little is known about whether common hamstring loading exercises specifically load different hamstring components. The purpose of this study was to investigate muscle activation of different components of the hamstring muscle during common hamstring loading exercises. Twenty elite female track and field athletes were recruited into this study, which had a single-sample, repeated-measures design. Each athlete performed ten hamstring loading exercises, and an electromyogram (EMG) was recorded from the biceps femoris and semitendinosus components of the hamstring. Hamstring EMG during maximal voluntary isometric contraction (MVIC) was used to normalize the mean data across ten repetitions of each exercise. An electrogoniometer synchronized to the EMG was used to determine whether peak EMG activity occurred during muscle-tendon unit lengthening, shortening, or no change in length. Mean EMG values were compared between the two recording sites for each exercise using the Student's t-test. The lunge, dead lift, and kettle swings were low intensity (<50% MVIC) and all showed higher EMG activity for semitendinosus than for biceps femoris. Bridge was low but approaching medium intensity, and the TRX, hamstring bridge, and hamstring curl were all medium intensity exercises (≥50% or <80% MVIC). The Nordic, fitball, and slide leg exercises were all high intensity exercises. Only the fitball exercise showed higher EMG activity in the biceps femoris compared with the semitendinosus. Only lunge and kettle swings showed peak EMG in the muscle-tendon unit lengthening phase and both these exercises involved faster speed. Some exercises selectively activated the lateral and medial distal hamstrings. Low, medium, and high intensity exercises were demonstrated. This information enables the clinician, strength and conditioning coach and physiotherapist to better understand intensity- and muscle-specific activation during hamstring muscle rehabilitation. Therefore, these results may help in designing progressive strengthening and rehabilitation and prevention programs.

Mechanisms of aerobic performance impairment with heat stress and dehydration.

PubMed

Cheuvront, Samuel N; Kenefick, Robert W; Montain, Scott J; Sawka, Michael N

2010-12-01

Environmental heat stress can challenge the limits of human cardiovascular and temperature regulation, body fluid balance, and thus aerobic performance. This minireview proposes that the cardiovascular adjustments accompanying high skin temperatures (T(sk)), alone or in combination with high core body temperatures (T(c)), provide a primary explanation for impaired aerobic exercise performance in warm-hot environments. The independent (T(sk)) and combined (T(sk) + T(c)) effects of hyperthermia reduce maximal oxygen uptake (Vo(2max)), which leads to higher relative exercise intensity and an exponential decline in aerobic performance at any given exercise workload. Greater relative exercise intensity increases cardiovascular strain, which is a prominent mediator of rated perceived exertion. As a consequence, incremental or constant-rate exercise is more difficult to sustain (earlier fatigue) or requires a slowing of self-paced exercise to achieve a similar sensation of effort. It is proposed that high T(sk) and T(c) impair aerobic performance in tandem primarily through elevated cardiovascular strain, rather than a deterioration in central nervous system (CNS) function or skeletal muscle metabolism. Evaporative sweating is the principal means of heat loss in warm-hot environments where sweat losses frequently exceed fluid intakes. When dehydration exceeds 3% of total body water (2% of body mass) then aerobic performance is consistently impaired independent and additive to heat stress. Dehydration augments hyperthermia and plasma volume reductions, which combine to accentuate cardiovascular strain and reduce Vo(2max). Importantly, the negative performance consequences of dehydration worsen as T(sk) increases.

Improvements in exercise performance with high-intensity interval training coincide with an increase in skeletal muscle mitochondrial content and function.

PubMed

Jacobs, Robert Acton; Flück, Daniela; Bonne, Thomas Christian; Bürgi, Simon; Christensen, Peter Møller; Toigo, Marco; Lundby, Carsten

2013-09-01

Six sessions of high-intensity interval training (HIT) are sufficient to improve exercise capacity. The mechanisms explaining such improvements are unclear. Accordingly, the aim of this study was to perform a comprehensive evaluation of physiologically relevant adaptations occurring after six sessions of HIT to determine the mechanisms explaining improvements in exercise performance. Sixteen untrained (43 ± 6 ml·kg(-1)·min(-1)) subjects completed six sessions of repeated (8-12) 60 s intervals of high-intensity cycling (100% peak power output elicited during incremental maximal exercise test) intermixed with 75 s of recovery cycling at a low intensity (30 W) over a 2-wk period. Potential training-induced alterations in skeletal muscle respiratory capacity, mitochondrial content, skeletal muscle oxygenation, cardiac capacity, blood volumes, and peripheral fatigue resistance were all assessed prior to and again following training. Maximal measures of oxygen uptake (Vo2peak; ∼8%; P = 0.026) and cycling time to complete a set amount of work (∼5%; P = 0.008) improved. Skeletal muscle respiratory capacities increased, most likely as a result of an expansion of skeletal muscle mitochondria (∼20%, P = 0.026), as assessed by cytochrome c oxidase activity. Skeletal muscle deoxygenation also increased while maximal cardiac output, total hemoglobin, plasma volume, total blood volume, and relative measures of peripheral fatigue resistance were all unaltered with training. These results suggest that increases in mitochondrial content following six HIT sessions may facilitate improvements in respiratory capacity and oxygen extraction, and ultimately are responsible for the improvements in maximal whole body exercise capacity and endurance performance in previously untrained individuals.

Influence of Upper-Body Exercise on the Fatigability of Human Respiratory Muscles

PubMed Central

TILLER, NICHOLAS B.; CAMPBELL, IAN G.; ROMER, LEE M.

2017-01-01

ABSTRACT Purpose Diaphragm and abdominal muscles are susceptible to contractile fatigue in response to high-intensity, whole-body exercise. This study assessed whether the ventilatory and mechanical loads imposed by high-intensity, upper-body exercise would be sufficient to elicit respiratory muscle fatigue. Methods Seven healthy men (mean ± SD; age = 24 ± 4 yr, peak O2 uptake [V˙O2peak] = 31.9 ± 5.3 mL·kg−1·min−1) performed asynchronous arm-crank exercise to exhaustion at work rates equivalent to 30% (heavy) and 60% (severe) of the difference between gas exchange threshold and V˙O2peak. Contractile fatigue of the diaphragm and abdominal muscles was assessed by measuring pre- to postexercise changes in potentiated transdiaphragmatic and gastric twitch pressures (Pdi,tw and Pga,tw) evoked by supramaximal magnetic stimulation of the cervical and thoracic nerves, respectively. Results Exercise time was 24.5 ± 5.8 min for heavy exercise and 9.8 ± 1.8 min for severe exercise. Ventilation over the final minute of heavy exercise was 73 ± 20 L·min−1 (39% ± 11% maximum voluntary ventilation) and 99 ± 19 L·min−1 (53% ± 11% maximum voluntary ventilation) for severe exercise. Mean Pdi,tw did not differ pre- to postexercise at either intensity (P > 0.05). Immediately (5–15 min) after severe exercise, mean Pga,tw was significantly lower than pre-exercise values (41 ± 13 vs 53 ± 15 cm H2O, P < 0.05), with the difference no longer significant after 25–35 min. Abdominal muscle fatigue (defined as ≥15% reduction in Pga,tw) occurred in 1/7 subjects after heavy exercise and 5/7 subjects after severe exercise. Conclusions High-intensity, upper-body exercise elicits significant abdominal, but not diaphragm, muscle fatigue in healthy men. The increased magnitude and prevalence of fatigue during severe-intensity exercise is likely due to additional (nonrespiratory) loading of the thorax. PMID:28288012

Influence of Upper-Body Exercise on the Fatigability of Human Respiratory Muscles.

PubMed

Tiller, Nicholas B; Campbell, Ian G; Romer, Lee M

2017-07-01

Diaphragm and abdominal muscles are susceptible to contractile fatigue in response to high-intensity, whole-body exercise. This study assessed whether the ventilatory and mechanical loads imposed by high-intensity, upper-body exercise would be sufficient to elicit respiratory muscle fatigue. Seven healthy men (mean ± SD; age = 24 ± 4 yr, peak O2 uptake [V˙O2peak] = 31.9 ± 5.3 mL·kg·min) performed asynchronous arm-crank exercise to exhaustion at work rates equivalent to 30% (heavy) and 60% (severe) of the difference between gas exchange threshold and V˙O2peak. Contractile fatigue of the diaphragm and abdominal muscles was assessed by measuring pre- to postexercise changes in potentiated transdiaphragmatic and gastric twitch pressures (Pdi,tw and Pga,tw) evoked by supramaximal magnetic stimulation of the cervical and thoracic nerves, respectively. Exercise time was 24.5 ± 5.8 min for heavy exercise and 9.8 ± 1.8 min for severe exercise. Ventilation over the final minute of heavy exercise was 73 ± 20 L·min (39% ± 11% maximum voluntary ventilation) and 99 ± 19 L·min (53% ± 11% maximum voluntary ventilation) for severe exercise. Mean Pdi,tw did not differ pre- to postexercise at either intensity (P > 0.05). Immediately (5-15 min) after severe exercise, mean Pga,tw was significantly lower than pre-exercise values (41 ± 13 vs 53 ± 15 cm H2O, P < 0.05), with the difference no longer significant after 25-35 min. Abdominal muscle fatigue (defined as ≥15% reduction in Pga,tw) occurred in 1/7 subjects after heavy exercise and 5/7 subjects after severe exercise. High-intensity, upper-body exercise elicits significant abdominal, but not diaphragm, muscle fatigue in healthy men. The increased magnitude and prevalence of fatigue during severe-intensity exercise is likely due to additional (nonrespiratory) loading of the thorax.

The Effect of an Acute Bout of Moderate-Intensity Aerobic Exercise on Motor Learning of a Continuous Tracking Task

PubMed Central

Snow, Nicholas J.; Mang, Cameron S.; Roig, Marc; Boyd, Lara A.

2016-01-01

Introduction There is evidence for beneficial effects of acute and long-term exercise interventions on several forms of memory, including procedural motor learning. In the present study we examined how performing a single bout of continuous moderate intensity aerobic exercise would impact motor skill acquisition and retention in young healthy adults, compared to a period of rest. We hypothesized that exercise would improve motor skill acquisition and retention, compared to motor practice alone. Materials and Methods Sixteen healthy adults completed sessions of aerobic exercise or seated rest that were immediately followed by practice of a novel motor task (practice). Exercise consisted of 30 minutes of continuous cycling at 60% peak O2 uptake. Twenty-four hours after practice, we assessed motor learning with a no-exercise retention test (retention). We also quantified changes in offline motor memory consolidation, which occurred between practice and retention (offline). Tracking error was separated into indices of temporal precision and spatial accuracy. Results There were no differences between conditions in the timing of movements during practice (p = 0.066), at retention (p = 0.761), or offline (p = 0.966). However, the exercise condition enabled participants to maintain spatial accuracy during practice (p = 0.477); whereas, following rest performance diminished (p = 0.050). There were no significant differences between conditions at retention (p = 0.532) or offline (p = 0.246). Discussion An acute bout of moderate-intensity aerobic exercise facilitated the maintenance of motor performance during skill acquisition, but did not influence motor learning. Given past work showing that pairing high intensity exercise with skilled motor practice benefits learning, it seems plausible that intensity is a key modulator of the effects of acute aerobic exercise on changes in complex motor behavior. Further work is necessary to establish a dose-response relationship between aerobic exercise and motor learning. PMID:26901664

Appetite and gut hormone responses to moderate-intensity continuous exercise versus high-intensity interval exercise, in normoxic and hypoxic conditions.

PubMed

Bailey, Daniel P; Smith, Lindsey R; Chrismas, Bryna C; Taylor, Lee; Stensel, David J; Deighton, Kevin; Douglas, Jessica A; Kerr, Catherine J

2015-06-01

This study investigated the effects of continuous moderate-intensity exercise (MIE) and high-intensity interval exercise (HIIE) in combination with short exposure to hypoxia on appetite and plasma concentrations of acylated ghrelin, peptide YY (PYY), and glucagon-like peptide-1 (GLP-1). Twelve healthy males completed four, 2.6 h trials in a random order: (1) MIE-normoxia, (2) MIE-hypoxia, (3) HIIE-normoxia, and (4) HIIE-hypoxia. Exercise took place in an environmental chamber. During MIE, participants ran for 50 min at 70% of altitude-specific maximal oxygen uptake (V˙O2max) and during HIIE performed 6 × 3 min running at 90% V˙O2max interspersed with 6 × 3 min active recovery at 50% V˙O2max with a 7 min warm-up and cool-down at 70% V˙O2max (50 min total). In hypoxic trials, exercise was performed at a simulated altitude of 2980 m (14.5% O2). Exercise was completed after a standardised breakfast. A second meal standardised to 30% of participants' daily energy requirements was provided 45 min after exercise. Appetite was suppressed more in hypoxia than normoxia during exercise, post-exercise, and for the full 2.6 h trial period (linear mixed modelling, p <0.05). Plasma acylated ghrelin concentrations were lower in hypoxia than normoxia post-exercise and for the full 2.6 h trial period (p <0.05). PYY concentrations were higher in HIIE than MIE under hypoxic conditions during exercise (p = 0.042). No differences in GLP-1 were observed between conditions (p > 0.05). These findings demonstrate that short exposure to hypoxia causes suppressions in appetite and plasma acylated ghrelin concentrations. Furthermore, appetite responses to exercise do not appear to be influenced by exercise modality. Copyright © 2015 Elsevier Ltd. All rights reserved.

High-intensity aerobic interval training can lead to improvement in skeletal muscle power among in-hospital patients with advanced heart failure.

PubMed

Taya, Masanobu; Amiya, Eisuke; Hatano, Masaru; Maki, Hisataka; Nitta, Daisuke; Saito, Akihito; Tsuji, Masaki; Hosoya, Yumiko; Minatsuki, Shun; Nakayama, Atsuko; Fujiwara, Takayuki; Konishi, Yuto; Yokota, Kazuhiko; Watanabe, Masafumi; Morita, Hiroyuki; Haga, Nobuhiko; Komuro, Issei

2018-01-15

This study investigated the effectiveness and safety of interval training during in-hospital treatment of patients with advanced heart failure. Twenty-four consecutive patients with advanced symptomatic heart failure who were referred for cardiac transplant evaluation were recruited. After performing aerobic exercise for approximate intensity, high-intensity interval training (HIIT) was performed. The protocol consisted of 3 or 4 sessions of 1-min high-intensity exercise aimed at 80% of peak VO 2 or 80% heart rate reserve, followed by 4-min recovery periods of low intensity. In addition to the necessary laboratory data, hand grip strength and knee extensor strength were evaluated at the start of exercise training and both at the start and the end of HIIT. Knee extensor strength was standardized by body weight. The BNP level at the start of exercise training was 432 (812) pg/mL and it significantly decreased to 254 (400) pg/mL (p < 0.001) at the end of HIIT. Hand grip strength did not change during course. By contrast, knee extensor strength significantly increased during HIIT [4.42 ± 1.43 → 5.28 ± 1.45 N/kg, p < 0.001], whereas the improvement of knee extensor strength was not significant from the start of exercise training to the start of HIIT. In addition, the change in knee extensor strength during HIIT was significantly associated with the hemoglobin A1c level at the start of exercise (R = - 0.55; p = 0.015). HIIT has a positive impact on skeletal muscle strength among in-hospital patients with advanced heart failure.

Comparable Neutrophil Responses for Arm and Intensity-matched Leg Exercise.

PubMed

Leicht, Christof A; Goosey-Tolfrey, Victoria L; Bishop, Nicolette C

2017-08-01

Arm exercise is performed at lower absolute intensities than lower body exercise. This may impact on intensity-dependent neutrophil responses, and it is unknown whether individuals restricted to arm exercise experience the same changes in the neutrophil response as found for lower body exercise. Therefore, we aimed to investigate the importance of exercise modality and relative exercise intensity on the neutrophil response. Twelve moderately trained men performed three 45-min constant load exercise trials after determination of peak oxygen uptake for arm exercise (V˙O2peak arms) and cycling (V˙O2peak legs): 1) arm cranking exercise at 60% V˙O2peak arms, 2) moderate cycling at 60% V˙O2peak legs, and 3) easy cycling at 60% V˙O2peak arms. Neutrophil numbers in the circulation increased for all exercise trials, but were significantly lower for easy cycling when compared with arm exercise (P = 0.009), mirroring the blunted increase in HR and epinephrine during easy cycling. For all trials, exercising HR explained some of the variation of the neutrophil number 2 h postexercise (R = 0.51-0.69), epinephrine explaining less of this variation (R = 0.21-0.34). The number of neutrophils expressing CXCR2 decreased in the recovery from exercise in all trials (P < 0.05). Arm and leg exercise elicits the same neutrophil response when performed at the same relative intensity, implying that populations restricted to arm exercise might achieve a similar exercise induced neutrophil response as those performing lower body exercise. A likely explanation for this is the higher sympathetic activation and cardiac output for arm and relative intensity-matched leg exercise when compared with easy cycling, which is partly reflected in HR. This study further shows that the downregulation of CXCR2 may be implicated in exercise-induced neutrophilia.

Carbohydrates and Physical/Mental Performance during Intermittent Exercise to Fatigue.

ERIC Educational Resources Information Center

Welsh, Ralph S.; Davis, J. Mark; Burke, Jean R.; Williams, Harriet G.

2002-01-01

Investigated the effects of carbohydrate-electrolyte (CHO) ingestion on physical and mental function associated with performing high-intensity exercise. Physically active adults completed physical activities while researchers assessed them. CHO or placebo drinks were consumed before starting and at halftime. CHO ingestion resulted in 37 percent…

Effect of exercise intensity on postprandial lipemia, markers of oxidative stress, and endothelial function after a high-fat meal.

PubMed

Lopes Krüger, Renata; Costa Teixeira, Bruno; Boufleur Farinha, Juliano; Cauduro Oliveira Macedo, Rodrigo; Pinto Boeno, Francesco; Rech, Anderson; Lopez, Pedro; Silveira Pinto, Ronei; Reischak-Oliveira, Alvaro

2016-12-01

The aim of this study was to compare the effects of 2 different exercise intensities on postprandial lipemia, oxidative stress markers, and endothelial function after a high-fat meal (HFM). Eleven young men completed 2-day trials in 3 conditions: rest, moderate-intensity exercise (MI-Exercise) and heavy-intensity exercise (HI-Exercise). Subjects performed an exercise bout or no exercise (Rest) on the evening of day 1. On the morning of day 2, an HFM was provided. Blood was sampled at fasting (0 h) and every hour from 1 to 5 h during the postprandial period for triacylglycerol (TAG), thiobarbituric acid reactive substance (TBARS), and nitrite/nitrate (NOx) concentrations. Flow-mediated dilatation (FMD) was also analyzed. TAG concentrations were reduced in exercise conditions compared with Rest during the postprandial period (P < 0.004). TAG incremental area under the curve (iAUC) was smaller after HI-Exercise compared with Rest (P = 0.012). TBARS concentrations were reduced in MI-Exercise compared with Rest (P < 0.041). FMD was higher in exercise conditions than Rest at 0 h (P < 0.02) and NOx concentrations were enhanced in MI-Exercise compared with Rest at 0 h (P < 0.01). These results suggest that acute exercise can reduce lipemia after an HFM. However, HI-Exercise showed to be more effective in reducing iAUC TAG, which might suggest higher protection against postprandial TAG enhancement. Conversely, MI-Exercise can be beneficial to attenuate the susceptibility of oxidative damage induced by an HFM and to increase endothelial function in the fasted state compared with Rest.

Association of Lower Limb Compression Garments During High-Intensity Exercise with Performance and Physiological Responses: A Systematic Review and Meta-analysis.

PubMed

da Silva, César Augusto; Helal, Lucas; da Silva, Roberto Pacheco; Belli, Karlyse Claudino; Umpierre, Daniel; Stein, Ricardo

2018-05-02

Although compression garments are used to improve sports performance, methodological approaches and the direction of evidence regarding garments for use in high-intensity exercise settings are diverse. Our primary aim was to summarize the association between lower-limb compression garments (LLCGs) and changes in sports performance during high-intensity exercise. We also aimed to summarize evidence about the following physiological parameters related to sports performance: vertical jump height (VJ), maximal oxygen uptake (VO 2 max), submaximal oxygen uptake (VO 2 submax), blood lactate concentrations ([La]), and ratings of perceived exertion (RPE, 6-20 Borg scale). We searched electronic databases (PubMed, EMBASE, Cochrane Library, and ClinicalTrials.gov) and reference lists for previous reviews. Eligible studies included randomized controlled trials with athletes or physically active subjects (≥ 18 years) using any type of LLCG during high-intensity exercise. The results were described as weighted mean difference (WMD) with a 95% confidence interval (95% CI). The 23 included studies showed low statistical heterogeneity for the pooled outcomes. We found that LLCGs yielded similar running performance to controls (50-400 m: WMD 0.06 s [95% CI - 1.99 to 2.11]; 800-3000 m: WMD 6.10 s [95% CI - 7.23 to 19.43]; > 5000 m: WMD 1.01 s [95% CI - 84.80 to 86.82]). Likewise, we found no evidence that LLCGs were superior in secondary outcomes (VJ: WMD 2.25 cm [95% CI - 2.51 to 7.02]; VO 2 max: WMD 0.24 mL.kg -1 .min -1 [95% CI - 1.48 to 1.95]; VO 2 submax: WMD - 0.26 mL.kg -1 .min -1 [95% CI - 2.66 to 2.14]; [La]: WMD 0.19 mmol/L [95% CI - 0.22 to 0.60]; RPE: WMD - 0.20 points [95% CI - 0.48 to 0.08]). LLCGs were not associated with improved performance in VJ, VO 2 max, VO 2 submax, [La], or RPE during high-intensity exercise. Such evidence should be taken into account when considering using LLCGs to enhance running performance.

Accuracy of Continuous Glucose Monitoring (CGM) during Continuous and High-Intensity Interval Exercise in Patients with Type 1 Diabetes Mellitus

PubMed Central

Moser, Othmar; Mader, Julia K.; Tschakert, Gerhard; Mueller, Alexander; Groeschl, Werner; Pieber, Thomas R.; Koehler, Gerd; Messerschmidt, Janin; Hofmann, Peter

2016-01-01

Continuous exercise (CON) and high-intensity interval exercise (HIIE) can be safely performed with type 1 diabetes mellitus (T1DM). Additionally, continuous glucose monitoring (CGM) systems may serve as a tool to reduce the risk of exercise-induced hypoglycemia. It is unclear if CGM is accurate during CON and HIIE at different mean workloads. Seven T1DM patients performed CON and HIIE at 5% below (L) and above (M) the first lactate turn point (LTP1), and 5% below the second lactate turn point (LTP2) (H) on a cycle ergometer. Glucose was measured via CGM and in capillary blood (BG). Differences were found in comparison of CGM vs. BG in three out of the six tests (p < 0.05). In CON, bias and levels of agreement for L, M, and H were found at: 0.85 (−3.44, 5.15) mmol·L−1, −0.45 (−3.95, 3.05) mmol·L−1, −0.31 (−8.83, 8.20) mmol·L−1 and at 1.17 (−2.06, 4.40) mmol·L−1, 0.11 (−5.79, 6.01) mmol·L−1, 1.48 (−2.60, 5.57) mmol·L−1 in HIIE for the same intensities. Clinically-acceptable results (except for CON H) were found. CGM estimated BG to be clinically acceptable, except for CON H. Additionally, using CGM may increase avoidance of exercise-induced hypoglycemia, but usual BG control should be performed during intense exercise. PMID:27517956

In dubio pro silentio - Even Loud Music Does Not Facilitate Strenuous Ergometer Exercise.

PubMed

Kreutz, Gunter; Schorer, Jörg; Sojke, Dominik; Neugebauer, Judith; Bullack, Antje

2018-01-01

Background: Music listening is wide-spread in amateur sports. Ergometer exercise is one such activity which is often performed with loud music. Aim and Hypotheses: We investigated the effects of electronic music at different intensity levels on ergometer performance (physical performance, force on the pedal, pedaling frequency), perceived fatigue and heart rate in healthy adults. We assumed that higher sound intensity levels are associated with greater ergometer performance and less perceived effort, particularly for untrained individuals. Methods: Groups of high trained and low trained healthy males ( N = 40; age = 25.25 years; SD = 3.89 years) were tested individually on an ergometer while electronic dance music was played at 0, 65, 75, and 85 dB. Participants assessed their music experience during the experiment. Results: Majorities of participants rated the music as not too loud (65%), motivating (77.50%), appropriate for this sports exercise (90%), and having the right tempo (67.50%). Participants noticed changes in the acoustical environment with increasing intensity levels, but no further effects on any of the physical or other subjective measures were found for neither of the groups. Therefore, the main hypothesis must be rejected. Discussion: These findings suggest that high loudness levels do not positively influence ergometer performance. The high acceptance of loud music and perceived appropriateness could be based on erroneous beliefs or stereotypes. Reasons for the widespread use of loud music in fitness sports needs further investigation. Reducing loudness during fitness exercise may not compromise physical performance or perceived effort.

Effect of moderate- and high-intensity acute exercise on appetite in obese individuals.

PubMed

Martins, Catia; Stensvold, Dorthe; Finlayson, Graham; Holst, Jens; Wisloff, Ulrik; Kulseng, Bård; Morgan, Linda; King, Neil A

2015-01-01

The effect of acute exercise, and exercise intensity, on appetite control in obese individuals requires further study. The aim of this study was to compare the effects of acute isocaloric bouts (250 kcal) of high-intensity intermittent cycling (HIIC) and moderate-intensity continuous cycling (MICC) or short-duration HIIC (S-HIIC) (125 kcal) and a resting control condition on the appetite hormone responses, subjective feelings of appetite, energy intake (EI), and food reward in overweight/obese individuals. This study is a randomized crossover study on 12 overweight/obese volunteers. Participants were assigned to the control, MICC, HIIC, and S-HIIC conditions, 1 wk apart, in a counterbalanced order. Exercise was performed 1 h after a standard breakfast. An ad libitum test lunch was served 3 h after breakfast. Fasting/postprandial plasma samples of insulin, acylated ghrelin, polypeptide YY3-36, and glucagon-like peptide 1 and subjective feelings of appetite were measured every 30 min for 3 h. Nutrient and taste preferences were measured at the beginning and end of each condition using the Leeds Food Preference Questionnaire. Insulin levels were significantly reduced, and glucagon-like peptide 1 levels significantly increased during all exercise bouts compared with those during rest. Acylated ghrelin plasma levels were lower in the MICC and HIIC, but not in S-HIIC, compared with those in control. There were no significant differences for polypeptide YY3-36 plasma levels, hunger or fullness ratings, EI, or food reward. Our findings suggest that, in overweight/obese individuals, isocaloric bouts of moderate- or high-intensity exercise lead to a similar appetite response. This strengthens previous findings in normal-weight individuals that acute exercise, even at high intensity, does not induce any known physiological adaptation that would lead to increased EI.

High-intensity exercise interventions in cancer survivors: a systematic review exploring the impact on health outcomes.

PubMed

Toohey, Kellie; Pumpa, Kate; McKune, Andrew; Cooke, Julie; Semple, Stuart

2018-01-01

There is an increasing body of evidence underpinning high-intensity exercise as an effective and time-efficient intervention for improving health in cancer survivors. The aim of this study was to, (1) evaluate the efficacy and (2) the safety of high-intensity exercise interventions in improving selected health outcomes in cancer survivors. Design Systematic review. Data sources Google Scholar and EBSCO, CINAHL Plus, Computers and Applied Sciences Complete, Health Source-Consumer Edition, Health Source: Nursing/Academic Edition, MEDLINE, Web of Science and SPORTDiscuss from inception up until August 2017. Eligibility criteria Randomized controlled trials of high-intensity exercise interventions in cancer survivors (all cancer types) with health-related outcome measures. The guidelines adopted for this review were the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). The search returned 447 articles, of which nine articles (n = 531 participants mean, age 58 ± 9.5 years) met the eligibility criteria. Exercise interventions of between 4 and 18 weeks consisting of high-intensity interval bouts of up to 4-min were compared with a continuous moderate intensity (CMIT) intervention or a control group. High-intensity exercise interventions elicited significant improvements in VO 2 max, strength, body mass, body fat and hip and waist circumference compared with CMIT and/or control groups. The studies reviewed showed low risk in participating in supervised high-intensity exercise interventions. Mixed mode high-intensity interventions which included both aerobic and resistance exercises were most effective improving the aerobic fitness levels of cancer survivors by 12.45-21.35%, from baseline to post-intervention. High-intensity exercise interventions improved physical and physiological health-related outcome measures such as cardiovascular fitness and strength in cancer survivors. Given that high-intensity exercise sessions require a shorter time commitment, it may be a useful modality to improve health outcomes in those who are time poor. The risk of adverse events associated with high-intensity exercise was low.

Endurance Performance during Severe-Intensity Intermittent Cycling: Effect of Exercise Duration and Recovery Type.

PubMed

Barbosa, Luis F; Denadai, Benedito S; Greco, Camila C

2016-01-01

Slow component of oxygen uptake (VO 2 SC) kinetics and maximal oxygen uptake (VO 2 max) attainment seem to influence endurance performance during constant-work rate exercise (CWR) performed within the severe intensity domain. In this study, it was hypothesized that delaying the attainment of VO 2 max by reducing the rates at which VO 2 increases with time (VO 2 SC kinetics) would improve the endurance performance during severe-intensity intermittent exercise performed with different work:recovery duration and recovery type in active individuals. After the estimation of the parameters of the VO 2 SC kinetics during CWR exercise, 18 males were divided into two groups (Passive and Active recovery) and performed at different days, two intermittent exercises to exhaustion (at 95% IVO 2 max, with work: recovery ratio of 2:1) with the duration of the repetitions calculated from the onset of the exercise to the beginning of the VO 2 SC (Short) or to the half duration of the VO 2 SC (Long). The active recovery was performed at 50% IVO 2 max. The endurance performance during intermittent exercises for the Passive (Short = 1523 ± 411; Long = 984 ± 260 s) and Active (Short = 902 ± 239; Long = 886 ± 254 s) groups was improved compared with CWR condition (Passive = 540 ± 116; Active = 489 ± 84 s). For Passive group, the endurance performance was significantly higher for Short than Long condition. However, no significant difference between Short and Long conditions was found for Active group. Additionally, the endurance performance during Short condition was higher for Passive than Active group. The VO 2 SC kinetics was significantly increased for CWR (Passive = 0.16 ± 0.04; Active = 0.16 ± 0.04 L.min -2 ) compared with Short (Passive = 0.01 ± 0.01; Active = 0.03 ± 0.04 L.min -2 ) and Long (Passive = 0.02 ± 0.01; Active = 0.01 ± 0.01 L.min -2 ) intermittent exercise conditions. No significant difference was found among the intermittent exercises. It can be concluded that the endurance performance is negatively influenced by active recovery only during shorter high-intensity intermittent exercise. Moreover, the improvement in endurance performance seems not be explained by differences in the VO 2 SC kinetics, since its values were similar among all intermittent exercise conditions.

Feasibility and effects of a combined adjuvant high-intensity interval/strength training in breast cancer patients: a single-center pilot study.

PubMed

Schulz, Sebastian Viktor Waldemar; Laszlo, Roman; Otto, Stephanie; Prokopchuk, Dmytro; Schumann, Uwe; Ebner, Florian; Huober, Jens; Steinacker, Jürgen Michael

2018-06-01

To evaluate feasibility of an exercise intervention consisting of high-intensity interval endurance and strength training in breast cancer patients. Twenty-six women with nonmetastatic breast cancer were consecutively assigned to the exercise intervention- (n= 15, mean age 51.9 ± 9.8 years) and the control group (n = 11, mean age 56.9 ± 7.0 years). Cardiopulmonary exercise testing that included lactate sampling, one-repetition maximum tests and a HADS-D questionnaire were used to monitor patients both before and after a supervised six weeks period of either combined high-intensity interval endurance and strength training (intervention group, twice a week) or leisure training (control group). Contrarily to the control group, endurance (mean change of VO 2 , peak 12.0 ± 13.0%) and strength performance (mean change of cumulative load 25.9 ± 11.2%) and quality of life increased in the intervention group. No training-related adverse events were observed. Our guided exercise intervention could be used effectively for initiation and improvement of performance capacity and quality of life in breast cancer patients in a relatively short time. This might be especially attractive during medical treatment. Long-term effects have to be evaluated in randomized controlled studies also with a longer follow-up. Implications for Rehabilitation High-intensity interval training allows improvement of aerobic capacity within a comparable short time. Standard leisure training in breast cancer patients is rather suitable for the maintenance of performance capacity and quality of life. Guided high-intensity interval training combined with strength training can be used effectively for the improvement of endurance and strength capacity and also quality of life. After exclusion of contraindications, guided adjuvant high-intensity interval training combined with strength training can be safely used in breast cancer patients.

Flavanol-rich cocoa consumption enhances exercise-induced executive function improvements in humans.

PubMed

Tsukamoto, Hayato; Suga, Tadashi; Ishibashi, Aya; Takenaka, Saki; Tanaka, Daichi; Hirano, Yoshitaka; Hamaoka, Takafumi; Goto, Kazushige; Ebi, Kumiko; Isaka, Tadao; Hashimoto, Takeshi

2018-02-01

Aerobic exercise is known to acutely improve cognitive functions, such as executive function (EF) and memory function (MF). Additionally, consumption of flavanol-rich cocoa has been reported to acutely improve cognitive function. The aim of this study was to determine whether high cocoa flavanol (CF; HCF) consumption would enhance exercise-induced improvement in cognitive function. To test this hypothesis, we examined the combined effects of HCF consumption and moderate-intensity exercise on EF and MF during postexercise recovery. Ten healthy young men received either an HCF (563 mg of CF) or energy-matched low CF (LCF; 38 mg of CF) beverage 70 min before exercise in a single-blind counterbalanced manner. The men then performed moderate-intensity cycling exercise at 60% of peak oxygen uptake for 30 min. The participants performed a color-word Stroop task and face-name matching task to evaluate EF and MF, respectively, during six time periods throughout the experimental session. EF significantly improved immediately after exercise compared with before exercise in both conditions. However, EF was higher after HCF consumption than after LCF consumption during all time periods because HCF consumption improved EF before exercise. In contrast, HCF consumption and moderate-intensity exercise did not improve MF throughout the experiment. The present findings demonstrated that HCF consumption before moderate-intensity exercise could enhance exercise-induced improvement in EF, but not in MF. Therefore, we suggest that the combination of HCF consumption and aerobic exercise may be beneficial for improving EF. Copyright © 2017 Elsevier Inc. All rights reserved.

Acute Hematological and Inflammatory Responses to High-intensity Exercise Tests: Impact of Duration and Mode of Exercise.

PubMed

Minuzzi, Luciele G; Carvalho, Humberto M; Brunelli, Diego T; Rosado, Fatima; Cavaglieri, Cláudia R; Gonçalves, Carlos E; Gaspar, Joana M; Rama, Luís M; Teixeira, Ana M

2017-07-01

The purpose of this study was to investigate the hematological and inflammatory responses to 4 maximal high-intensity protocols, considering energy expenditure in each test. 9 healthy volunteers performed 4 high-intensity exercise tests of short [Wingate (WANT); Repeated-sprints (RSA)] and long durations [Continuous VO 2 test (VCONT); intermittent VO 2 test (VINT)] in a cycle-ergometer, until exhaustion. Hematological parameters and IL-6, IL-10 and creatine kinase (CK) levels were determined before (PRE), POST, 30 min, 1, 2, 12 and 24 h after the end of the protocols. Additionally, energy expenditure was determined. Leucocytes, erythrocytes and lymphocytes increased at POST and returned to PRE values at 30 min for all protocols. Lymphocytes had a second decreased at 2 h and granulocytes increased at 2 h when compared to PRE. Both variables returned to PRE values between 12-24 h into recovery. The magnitude of response for IL-6 was greater in VINT and for IL-10 in VCONT. There was no association of energy expenditure within each exercise protocol with the pattern of IL-6, IL-10 and CK responses to the exercise protocols. The present finding support that similar responses after continuous or intermittent acute protocols are observed when exercises are performed to volitional failure, regardless of the duration and mode of exercise. © Georg Thieme Verlag KG Stuttgart · New York.

The roles of the Na+/K+-ATPase, NKCC, and K+ channels in regulating local sweating and cutaneous blood flow during exercise in humans in vivo.

PubMed

Louie, Jeffrey C; Fujii, Naoto; Meade, Robert D; Kenny, Glen P

2016-11-01

Na + /K + -ATPase has been shown to regulate the sweating and cutaneous vascular responses during exercise; however, similar studies have not been conducted to assess the roles of the Na-K-2Cl co-transporter (NKCC) and K + channels. Additionally, it remains to be determined if these mechanisms underpinning the heat loss responses differ with exercise intensity. Eleven young (24 ± 4 years) males performed three 30-min semirecumbent cycling bouts at low (30% VO 2peak ), moderate (50% VO 2peak ), and high (70% VO 2peak ) intensity, respectively, each separated by 20-min recovery periods. Using intradermal microdialysis, four forearm skin sites were continuously perfused with either: (1) lactated Ringer solution (Control); (2) 6 mmol·L -1 ouabain (Na + /K + -ATPase inhibitor); (3) 10 mmol·L -1 bumetanide (NKCC inhibitor); or (4) 50 mmol·L -1 BaCl 2 (nonspecific K + channel inhibitor); sites at which we assessed local sweat rate (LSR) and cutaneous vascular conductance (CVC). Inhibition of Na + /K + -ATPase attenuated LSR compared to Control during the moderate and high-intensity exercise bouts (both P ˂ 0.01), whereas attenuations with NKCC and K + channel inhibition were only apparent during the high-intensity exercise bout (both P ≤ 0.05). Na + /K + -ATPase inhibition augmented CVC during all exercise intensities (all P ˂ 0.01), whereas CVC was greater with NKCC inhibition during the low-intensity exercise only (P ˂ 0.01) and attenuated with K + channel inhibition during the moderate and high-intensity exercise conditions (both P ˂ 0.01). We show that Na + /K + -ATPase, NKCC and K +  channels all contribute to the regulation of sweating and cutaneous blood flow but their influence is dependent on the intensity of dynamic exercise. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Acute and Post-Exercise Physiological Responses to High-Intensity Interval Training in Endurance and Sprint Athletes.

PubMed

Cipryan, Lukas; Tschakert, Gerhard; Hofmann, Peter

2017-06-01

The purpose of the presented study was to compare acute and post-exercise differences in cardiorespiratory, metabolic, cardiac autonomic, inflammatory and muscle damage responses to high-intensity interval exercise (HIIT) between endurance and sprint athletes. The study group consisted of sixteen highly-trained males (age 22.1 ± 2.5 years) participating in endurance (n = 8) or sprint (n = 8) sporting events. All the participants underwent three exercise sessions: short HIIT (work interval duration 30s), long HIIT (3min) and constant load exercise (CE). The exercise interventions were matched for mean power, total time and in case of HIIT interventions also for work-to-relief ratio. The acute cardiorespiratory (HR, V̇ O 2 , RER) and metabolic (lactate) variables as well as the post-exercise changes (up to 3 h) in the heart rate variability, inflammation (interleukin-6, leucocytes) and muscle damage (creatine kinase, myoglobin) were monitored. Endurance athletes performed exercise interventions with moderately (CE) or largely (both HIIT modes) higher mean V̇ O 2 . These differences were trivial/small when V̇ O 2 was expressed as a percentage of V̇ O 2max . Moderately to largely lower RER and lactate values were found in endurance athletes. Markers of cardiac autonomic regulation, inflammation and muscle damage did not reveal any considerable differences between endurance and sprint athletes. In conclusions, endurance athletes were able to perform both HIIT formats with increased reliance on aerobic metabolic pathways although exercise intensity was identical in relative terms for all the participants. However, other markers of the acute and early post-exercise physiological response to these HIIT interventions indicated similarities between endurance and sprint athletes.

The relation between exercise and glaucoma in a South Korean population-based sample.

PubMed

Lin, Shuai-Chun; Wang, Sophia Y; Pasquale, Louis R; Singh, Kuldev; Lin, Shan C

2017-01-01

To investigate the association between exercise and glaucoma in a South Korean population-based sample. Population-based, cross-sectional study. A total of 11,246 subjects, 40 years and older who underwent health care assessment as part of the 2008-2011 Korean National Health and Nutrition Examination Survey. Variables regarding the duration (total minutes per week), frequency (days per week), and intensity of exercise (vigorous, moderate exercise and walking) as well as glaucoma prevalence were ascertained for 11,246 survey participants. Demographic, comorbidity, and health-related behavior information was obtained via interview. Multivariable logistic regression analyses were performed to determine the association between the exercise-related parameters and odds of a glaucoma diagnosis. Glaucoma defined by International Society for Geographical and Epidemiological Ophthalmology criteria. Overall, 336 (2.7%) subjects met diagnostic criteria for glaucomatous disease. After adjustment for potential confounding variables, subjects engaged in vigorous exercise 7 days per week had higher odds of having glaucoma compared with those exercising 3 days per week (Odds Ratio [OR] 3.33, 95% confidence interval [CI] 1.16-9.54). High intensity of exercise, as categorized by the guidelines of the American College of Sports Medicine (ACSM), was also associated with greater glaucoma prevalence compared with moderate intensity of exercise (OR 1.55, 95% CI 1.03-2.33). There was no association between other exercise parameters including frequency of moderate exercise, walking, muscle strength exercise, flexibility training, or total minutes of exercise per week, and the prevalence of glaucoma. In sub-analyses stratifying by gender, the association between frequency of vigorous exercise 7 days per week and glaucoma diagnosis remained significant in men (OR 6.05, 95% CI 1.67-21.94) but not in women (OR 0.96 95% CI: 0.23-3.97). A U-shaped association between exercise intensity and glaucoma prevalence was noted in men (OR 1.71, 95% CI 1.09-2.69 for low intensity versus moderate intensity; OR 2.19, 95% CI 1.25-3.85 for high intensity versus moderate intensity). In a South Korean population sample, daily vigorous exercise was associated with higher glaucoma prevalence. In addition, the intensity of exercise was positively associated with glaucoma diagnosis in men but not women.

The relation between exercise and glaucoma in a South Korean population-based sample

PubMed Central

Lin, Shuai-Chun; Wang, Sophia Y.; Pasquale, Louis R.; Singh, Kuldev; Lin, Shan C.

2017-01-01

Purpose To investigate the association between exercise and glaucoma in a South Korean population-based sample. Design Population-based, cross-sectional study. Participants A total of 11,246 subjects, 40 years and older who underwent health care assessment as part of the 2008–2011 Korean National Health and Nutrition Examination Survey. Methods Variables regarding the duration (total minutes per week), frequency (days per week), and intensity of exercise (vigorous, moderate exercise and walking) as well as glaucoma prevalence were ascertained for 11,246 survey participants. Demographic, comorbidity, and health-related behavior information was obtained via interview. Multivariable logistic regression analyses were performed to determine the association between the exercise-related parameters and odds of a glaucoma diagnosis. Main outcome measure(s) Glaucoma defined by International Society for Geographical and Epidemiological Ophthalmology criteria. Results Overall, 336 (2.7%) subjects met diagnostic criteria for glaucomatous disease. After adjustment for potential confounding variables, subjects engaged in vigorous exercise 7 days per week had higher odds of having glaucoma compared with those exercising 3 days per week (Odds Ratio [OR] 3.33, 95% confidence interval [CI] 1.16–9.54). High intensity of exercise, as categorized by the guidelines of the American College of Sports Medicine (ACSM), was also associated with greater glaucoma prevalence compared with moderate intensity of exercise (OR 1.55, 95% CI 1.03–2.33). There was no association between other exercise parameters including frequency of moderate exercise, walking, muscle strength exercise, flexibility training, or total minutes of exercise per week, and the prevalence of glaucoma. In sub-analyses stratifying by gender, the association between frequency of vigorous exercise 7 days per week and glaucoma diagnosis remained significant in men (OR 6.05, 95% CI 1.67–21.94) but not in women (OR 0.96 95% CI: 0.23–3.97). A U-shaped association between exercise intensity and glaucoma prevalence was noted in men (OR 1.71, 95% CI 1.09–2.69 for low intensity versus moderate intensity; OR 2.19, 95% CI 1.25–3.85 for high intensity versus moderate intensity). Conclusion In a South Korean population sample, daily vigorous exercise was associated with higher glaucoma prevalence. In addition, the intensity of exercise was positively associated with glaucoma diagnosis in men but not women. PMID:28187143

High-Intensity Interval Training Elicits Higher Enjoyment than Moderate Intensity Continuous Exercise

PubMed Central

Thum, Jacob S.; Parsons, Gregory; Whittle, Taylor

2017-01-01

Exercise adherence is affected by factors including perceptions of enjoyment, time availability, and intrinsic motivation. Approximately 50% of individuals withdraw from an exercise program within the first 6 mo of initiation, citing lack of time as a main influence. Time efficient exercise such as high intensity interval training (HIIT) may provide an alternative to moderate intensity continuous exercise (MICT) to elicit substantial health benefits. This study examined differences in enjoyment, affect, and perceived exertion between MICT and HIIT. Twelve recreationally active men and women (age = 29.5 ± 10.7 yr, VO2max = 41.4 ± 4.1 mL/kg/min, BMI = 23.1 ± 2.1 kg/m2) initially performed a VO2max test on a cycle ergometer to determine appropriate workloads for subsequent exercise bouts. Each subject returned for two additional exercise trials, performing either HIIT (eight 1 min bouts of cycling at 85% maximal workload (Wmax) with 1 min of active recovery between bouts) or MICT (20 min of cycling at 45% Wmax) in randomized order. During exercise, rating of perceived exertion (RPE), affect, and blood lactate concentration (BLa) were measured. Additionally, the Physical Activity Enjoyment Scale (PACES) was completed after exercise. Results showed higher enjoyment (p = 0.013) in response to HIIT (103.8 ± 9.4) versus MICT (84.2 ± 19.1). Eleven of 12 participants (92%) preferred HIIT to MICT. However, affect was lower (p<0.05) and HR, RPE, and BLa were higher (p<0.05) in HIIT versus MICT. Although HIIT is more physically demanding than MICT, individuals report greater enjoyment due to its time efficiency and constantly changing stimulus. Trial Registration: NCT:02981667. PMID:28076352

High-Intensity Interval Training Elicits Higher Enjoyment than Moderate Intensity Continuous Exercise.

PubMed

Thum, Jacob S; Parsons, Gregory; Whittle, Taylor; Astorino, Todd A

2017-01-01

Exercise adherence is affected by factors including perceptions of enjoyment, time availability, and intrinsic motivation. Approximately 50% of individuals withdraw from an exercise program within the first 6 mo of initiation, citing lack of time as a main influence. Time efficient exercise such as high intensity interval training (HIIT) may provide an alternative to moderate intensity continuous exercise (MICT) to elicit substantial health benefits. This study examined differences in enjoyment, affect, and perceived exertion between MICT and HIIT. Twelve recreationally active men and women (age = 29.5 ± 10.7 yr, VO2max = 41.4 ± 4.1 mL/kg/min, BMI = 23.1 ± 2.1 kg/m2) initially performed a VO2max test on a cycle ergometer to determine appropriate workloads for subsequent exercise bouts. Each subject returned for two additional exercise trials, performing either HIIT (eight 1 min bouts of cycling at 85% maximal workload (Wmax) with 1 min of active recovery between bouts) or MICT (20 min of cycling at 45% Wmax) in randomized order. During exercise, rating of perceived exertion (RPE), affect, and blood lactate concentration (BLa) were measured. Additionally, the Physical Activity Enjoyment Scale (PACES) was completed after exercise. Results showed higher enjoyment (p = 0.013) in response to HIIT (103.8 ± 9.4) versus MICT (84.2 ± 19.1). Eleven of 12 participants (92%) preferred HIIT to MICT. However, affect was lower (p<0.05) and HR, RPE, and BLa were higher (p<0.05) in HIIT versus MICT. Although HIIT is more physically demanding than MICT, individuals report greater enjoyment due to its time efficiency and constantly changing stimulus. NCT:02981667.

Ergogenic and metabolic effects of oral glucocorticoid intake during repeated bouts of high-intensity exercise.

PubMed

Zorgati, Houssem; Prieur, Fabrice; Vergniaud, Thomas; Cottin, François; Do, Manh-Cuong; Labsy, Zakaria; Amarantini, David; Gagey, Olivier; Lasne, Françoise; Collomp, Katia

2014-08-01

All systemically administered glucocorticoids (GC) are prohibited in-competition, because of the potential ergogenic effects. Although short-term GC intake has been shown to improve performance during submaximal exercise, literature on its impact during brief intense exercise appears to be very scant. The purpose of this study was to examine the ergogenic and metabolic effects of prednisone during repeated bouts of high-intensity exercise. In a double-blind randomized protocol, ten recreational male athletes followed two 1-week treatments (Cor: prednisone, 60mg/day or Pla: placebo). At the end of each treatment, they hopped on their dominant leg for 30s three times consecutively and then hopped until exhaustion, with intervals of 5min of passive recovery. Blood and saliva samples were collected at rest and 3min after each exercise bout to determine the lactate, interleukin-6, interleukin-10, TNF-alpha, DHEA and testosterone values. The absolute peak force of the dominant leg was significantly increased by Cor but only during the first 30-s hopping bout (p<0.05), whereas time to exhaustion was not significantly changed after Cor treatment vs Pla (Pla: 119.9±24.7; Cor: 123.1±29.5s). Cor intake lowered basal and end-exercise plasma interleukin-6 and saliva DHEA (p<0.01) and increased interleukin-10 (p<0.01), whereas no significant change was found in blood lactate and TNF-alpha or saliva testosterone between Pla and Cor. According to these data, short-term glucocorticoid intake did not improve endurance performance during repeated bouts of high-intensity exercise, despite the significant initial increase in absolute peak force and anti-inflammatory effect. Copyright © 2014 Elsevier Inc. All rights reserved.

Design of the Resistance and Endurance exercise After ChemoTherapy (REACT) study: a randomized controlled trial to evaluate the effectiveness and cost-effectiveness of exercise interventions after chemotherapy on physical fitness and fatigue.

PubMed

Kampshoff, Caroline S; Buffart, Laurien M; Schep, Goof; van Mechelen, Willem; Brug, Johannes; Chinapaw, Mai J M

2010-11-30

Preliminary studies suggest that physical exercise interventions can improve physical fitness, fatigue and quality of life in cancer patients after completion of chemotherapy. Additional research is needed to rigorously test the effects of exercise programmes among cancer patients and to determine optimal training intensity accordingly. The present paper presents the design of a randomized controlled trial evaluating the effectiveness and cost-effectiveness of a high intensity exercise programme compared to a low-to-moderate intensity exercise programme and a waiting list control group on physical fitness and fatigue as primary outcomes. After baseline measurements, cancer patients who completed chemotherapy are randomly assigned to either a 12-week high intensity exercise programme or a low-to-moderate intensity exercise programme. Next, patients from both groups are randomly assigned to immediate training or a waiting list (i.e. waiting list control group). After 12 weeks, patients of the waiting list control group start with the exercise programme they have been allocated to.Both interventions consist of equal bouts of resistance and endurance interval exercises with the same frequency and duration, but differ in training intensity. Additionally, patients of both exercise programmes are counselled to improve compliance and achieve and maintain an active lifestyle, tailored to their individual preferences and capabilities.Measurements will be performed at baseline (t = 0), 12 weeks after randomization (t = 1), and 64 weeks after randomization (t = 2). The primary outcome measures are cardiorespiratory fitness and muscle strength assessed by means of objective performance indicators, and self-reported fatigue. Secondary outcome measures include health-related quality of life, self-reported physical activity, daily functioning, body composition, mood and sleep disturbances, and return to work. In addition, compliance and satisfaction with the interventions will be evaluated. Potential moderation by pre- and post-illness lifestyle, health and exercise-related attitudes, beliefs and motivation will also be assessed. Finally, the cost-effectiveness of both exercise interventions will be evaluated. This randomized controlled trial will be a rigorous test of effects of exercise programmes for cancer patients after chemotherapy, aiming to contribute to evidence-based practice in cancer rehabilitation programmes. This study is registered at the Netherlands Trial Register (NTR2153).

Physical exercise and health.

PubMed

Cordero, Alberto; Masiá, M Dolores; Galve, Enrique

2014-09-01

Regular physical exercise is an established recommendation for preventing and treating the main modifiable cardiovascular risk factors, such as diabetes mellitus, hypertension, and dyslipidemia. Performing physical activity of moderate intensity for a minimum of 30 min 5 days a week or of high intensity for a minimum of 20 min 3 days a week improves functional capacity and is associated with reductions in the incidence of cardiovascular disease and mortality. Physical exercise induces physiological cardiovascular adaptations that improve physical performance, and only in extreme cases can these adaptations lead to an increased risk of physical exercise-associated complications. The incidence of sudden death or serious complications during physical exercise is very low and is concentrated in people with heart diseases or with pathological cardiac adaptation to exercise. Most of these cases can be detected by cardiology units or well-trained professionals. Copyright © 2014 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

New perspectives concerning feedback influences on cardiorespiratory control during rhythmic exercise and on exercise performance.

PubMed

Dempsey, Jerome A

2012-09-01

The cardioaccelerator and ventilatory responses to rhythmic exercise in the human are commonly viewed as being mediated predominantly via feedforward 'central command' mechanisms, with contributions from locomotor muscle afferents to the sympathetically mediated pressor response. We have assessed the relative contributions of three types of feedback afferents on the cardiorespiratory response to voluntary, rhythmic exercise by inhibiting their normal 'tonic' activity in healthy animals and humans and in chronic heart failure. Transient inhibition of the carotid chemoreceptors during moderate intensity exercise reduced muscle sympathetic nerve activity (MSNA) and increased limb vascular conductance and blood flow; and reducing the normal level of respiratory muscle work during heavier intensity exercise increased limb vascular conductance and blood flow. These cardiorespiratory effects were prevented via ganglionic blockade and were enhanced in chronic heart failure and in hypoxia. Blockade of μ opioid sensitive locomotor muscle afferents, with preservation of central motor output via intrathecal fentanyl: (a) reduced the mean arterial blood pressure (MAP), heart rate and ventilatory responses to all steady state exercise intensities; and (b) during sustained high intensity exercise, reduced O(2) transport, increased central motor output and end-exercise muscle fatigue and reduced endurance performance. We propose that these three afferent reflexes - probably acting in concert with feedforward central command - contribute significantly to preserving O(2) transport to locomotor and to respiratory muscles during exercise. Locomotor muscle afferents also appear to provide feedback concerning the metabolic state of the muscle to influence central motor output, thereby limiting peripheral fatigue development.

Acute recovery from exercise in people with multiple sclerosis: an exploratory study on the effect of exercise intensities.

PubMed

Collett, Johnny; Meaney, Andy; Howells, Ken; Dawes, Helen

2017-03-01

Purpose A better understanding of how people with multiple sclerosis (pwMS) recover from exercise may help inform interventions. Methods We explored physiological and perceptual responses following exercise of different intensities, using a crossover exposure-response design, in 14 adults with multiple sclerosis (MS) and 9 controls. A cycling exercise test determined maximum capacity (Wpeak). Participants then performed 20-min exercise sessions relative to Wpeak (random order separated by 7 days): (1) 45% and (2) 60% continuous cycling and (3) 90% intermittent cycling (30 s cycling, 30 s rest). During a 45-min recovery period, tympanic temperature (Temp°C), exertion in breathing (RPEbr) and legs (RPEleg), and cortical excitability (MEParea) were measured. Results Eleven pwMS and eight controls completed the study. Controls performed better on the exercise test (p < 0.05), thus more absolute work during subsequent sessions. PwMS took longer to recover RPEleg with recovery time increasing with intensity (45%-6 min; 60%-15 min; 90%-35 min) and correlating with Temp°C. MEParea was significantly depressed in both groups at 45% and 60% (p < 0.001), in the MS group this also correlated with RPEleg. Conclusions Feelings of leg exertion may persist after exercise in some pwMS, especially at high intensities. This may relate to body temperature and, after continuous exercise, cortical excitability. These results support considering the recovery period post exercise and provide an insight into potential correlates of post-exercise fatigue. Implications for Rehabilitation A better understanding of how pwMS recover following exercise may help inform exercise prescription a long side fatigue management. This study showed that, in pwMS, the time taken to recover from feelings of leg fatigue increased with the intensity of the exercise session rather that total work performed and was related to increase in body temperature. The results of this relatively small study support the need to consider a recovery period after exercise and provide an insight into potential physiological correlates.

The Effect of Acute Exercise on Affect and Arousal in Inpatient Mental Health Consumers.

PubMed

Stanton, Robert; Reaburn, Peter; Happell, Brenda

2016-09-01

Acute exercise performed at a self-selected intensity improves affect and may improve long-term adherence. Similarly, in people with severe depression, acute aerobic exercise performed at self-selected intensity improves affect and arousal. However, the relationship between changes in affect and arousal and perceived exercise intensity in people with mental illness has not been evaluated. Affect and arousal were assessed immediately prior to, and immediately following, a group exercise program performed at a self-selected intensity in 40 inpatient mental health consumers who received a diagnosis of anxiety or bipolar or depressive disorders. Exercise intensity was assessed immediately after exercise. Postexercise affect was significantly improved for people with bipolar and depressive disorders but not for people with anxiety disorders. For the group as a whole, results showed a significant curvilinear relationship between ratings of perceived exertion and postexercise affect. These data will inform the development and delivery of future exercise interventions for inpatient mental health consumers.

Effects of GI meals on intermittent exercise.

PubMed

Hulton, A T; Gregson, W; Maclaren, D; Doran, D A

2012-09-01

Pre-exercise meals or single foods containing low glycaemic index (LGI) carbohydrates (CHO) have been shown to enhance performance prior to prolonged steady state exercise compared to high glycaemic index (HGI) CHO. This study investigated the impact of HGI and LGI pre-exercise meals on intermittent high intensity exercise. Nine male recreational football players performed a football specific protocol followed by a 1 km time trial 3.5 h after ingesting 1 of 2 isoenergetic test meals (HGI: 870.3 kcal, LGI: 889.5 kcal), which were either HGI (GI: 80) or LGI (GI: 44). Blood glucose, fatty acids (FA), glycerol, β-hydroxybutyrate, lactate and insulin were assessed before, during, and after the exercise bout, whilst rates of CHO and fat oxidation were determined at 4 time points during the protocol. No significant differences were found for the 1 km time trial (LGI: 210.2 ± 19.1 s: HGI: 215.8 ± 22.6 s) (mean ± SD), nor for any of the other variables measured (P>0.05) apart from a significant condition effect with FA and significant interaction effects observed for glucose, β-hydroxybutyrate and lactate (P<0.05). These findings suggest that the type of CHO ingested in a pre-match meal has no significant impact on performance or metabolic responses during 90 min of intermittent high intensity exercise. © Georg Thieme Verlag KG Stuttgart · New York.

Water intake accelerates parasympathetic reactivation after high-intensity exercise.

PubMed

Peçanha, Tiago; Paula-Ribeiro, Marcelle; Campana-Rezende, Edson; Bartels, Rhenan; Marins, João Carlos; de Lima, Jorge Roberto

2014-10-01

It has been shown that water intake (WI) improves postexercise parasympathetic recovery after moderate-intensity exercise session. However, the potential cardiovascular benefit promoted by WI has not been investigated after high-intensity exercise. To assess the effects of WI on post high-intensity parasympathetic recovery. Twelve recreationally active young men participated in the study (22 ± 1.4 years, 24.1 ± 1.6 kg.m(-2)). The experimental protocol consisted of two visits to the laboratory. Each visit consisted in the completion of a 30-min high-intensity [~80% of maximal heart rate (HR)] cycle ergometer aerobic session performing randomly the WI or control (CON, no water consumption) intervention at the end of the exercise. HR and RR intervals (RRi) were continuously recorded by a heart rate monitor before, during and after the exercise. Differences in HR recovery [e.g., absolute heart rate decrement after 1 min of recovery (HRR60s) and time-constant of the first order exponential fitting curve of the HRR (HRRτ)] and in postexercise vagal-related heart rate variability (HRV) indexes (rMSSD30s, rMSSD, pNN50, SD1 and HF) were calculated and compared for WI and CON. A similar HR recovery and an increased postexercise HRV [SD1 = 9.4 ± 5.9 vs. 6.0 ± 3.9 millisecond, HF(ln) = 3.6 ± 1.4 vs. 2.4 ± 1.3 millisecond(2), for WI and CON, respectively; p < .05] was observed in WI compared with CON. The results suggest that WI accelerates the postexercise parasympathetic reactivation after high-intensity exercise. Such outcome reveals an important cardioprotective effect of WI.

Calcineurin-NFAT Signaling and Neurotrophins Control Transformation of Myosin Heavy Chain Isoforms in Rat Soleus Muscle in Response to Aerobic Treadmill Training.

PubMed

Liu, Wenfeng; Chen, Gan; Li, Fanling; Tang, Changfa; Yin, Dazhong

2014-12-01

This study elucidated the role of CaN-NFAT signaling and neurotrophins on the transformation of myosin heavy chain isoforms in the rat soleus muscle fiber following aerobic exercise training. To do so, we examined the content and distribution of myosin heavy chain (MyHC) isoforms in the rat soleus muscle fiber, the activity of CaN and expression of NFATc1 in these fibers, and changes in the expression of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and neutrophin-3 (NT-3) in the soleus and striatum following high-and medium-intensity aerobic treadmill training. Specific pathogen-free 2 month old male Sprague-Dawley (SD) rats were randomly divided into three groups: Control group (Con, n = 8), moderate-intensity aerobic exercise group (M-Ex, n = 8) and high-intensity aerobic exercise group (H-Ex, n = 8). We used ATPase staining to identify the muscle fiber type I and II, SDS-PAGE to separate and analyze the isoforms MyHCI, MyHCIIA, MyHCIIB and MyHCIIx, and performed western blots to determine the expression of NFATc1, NGF, BDNF and NT-3. CaN activity was measured using a colorimetric assay. In the soleus muscle, 8 weeks of moderate-intensity exercise can induce transformation of MyHC IIA and MyHC IIB to MyHC IIX and MyHC I (p < 0.01), while high-intensity treadmill exercise can induce transform MyHC IIx to MyHC IIB, MyHC IIA and MyHC I (p < 0.01). In comparison to the control group, CaN activity and NFATcl protein level were significantly increased in both the M-Ex and H-Ex groups (p < 0.05, p < 0.01), with a more pronounced upregulation in the M-Ex group (p < 0.05). Eight weeks of moderate- and high-intensity aerobic exercise induced the expression of NGF, BDNF and NT-3 in the soleus muscle and the striatum (p < 0.01), with the most significant increase in the H-Ex group (p < 0.01). In the rat soleus muscle, (1) CaN-NFATcl signaling contributes to the conversion of MyHC I isoform in response to moderate-intensity exercise; (2) Neurotrophins NGF, BDNF and NT-3 might play a role in the conversion of MyHC II isoform in response to high-intensity treadmill exercise. Key pointsEight weeks of moderate-intensity treadmill training induces the transformation MyHC IIA and MyHC IIB to MyHC IIX and MyHC I in the soleus muscles, while high-intensity exercise leads to transformation of MyHC IIX to MyHC IIA, MyHC IIB and MyHC I.MyHC I conversion in response to moderate-intensity aerobic exercise is mediated by calcineurin-NFATcl signaling.Eight weeks of moderate- and high-ntensity aerobic exercise induces the expression of NGF, BDNF and NT-3 in expression noted in rats subjected to high-intensity training. NGF and NT-3 expression in the striatum is lower than in the soleus muscle, while BDNF levels are similar. Neurotrophins may be involved in mediating MyHC II conversion in response to high-intensity aerobic exercise.

High-intensity body weight training is comparable to combined training in changes in muscle mass, physical performance, inflammatory markers and metabolic health in postmenopausal women at high risk for type 2 diabetes mellitus: A randomized controlled clinical trial.

PubMed

Martins, Fernanda Maria; de Paula Souza, Aletéia; Nunes, Paulo Ricardo Prado; Michelin, Márcia Antoniazi; Murta, Eddie Fernando Candido; Resende, Elisabete Aparecida Mantovani Rodrigues; de Oliveira, Erick Prado; Orsatti, Fábio Lera

2018-07-01

This study compared the effects of 12 weeks of high-intensity interval body weight training (HIBWT) with combined training (COMT; aerobic and resistance exercises on body composition, a 6-minute walk test (6MWT; physical performance), insulin resistance (IR) and inflammatory markers in postmenopausal women (PW) at high risk of type 2 diabetes mellitus (TDM2). In this randomized controlled clinical study, 16 PW at high risk of TDM2 were randomly allocated into two groups: HIBWT (n = 8) and COMT (n = 8). The HIBWT group performed a training protocol (length time ~28 min) consisting of ten sets of 60 s of high intensity exercise interspersed by a recovery period of 60 s of low intensity exercise. The COMT group performed a training protocol (length time ~60 min) consisting of a 30 min walk of moderate intensity following by five resistance exercises. All training sessions were performed in the university gym facility three days a week (no consecutive days) for 12 weeks. All outcomes (body composition, muscle function, and IR and inflammatory markers) were assessed at the baseline and at the end of the study. Both groups increased (P < 0.05) muscle mass index (MMI), 6MWT, and interleukin 1 receptor antagonist and decreased fasting glucose, glycated hemoglobin , Insulin, HOMA-IR, and monocyte chemoattractant protein-1 (trend, P = 0.056). HIBWT effects were indistinguishable (P > 0.05) from the effects of COMT. There was a significant (P < 0.05) interaction of time by the group in muscle strength, indicating that only the COMT increased the muscle strength. This study suggests that changes in HOMA, IL-1ra, 6MWT, and MMI with HITBW are similar when compared to COMT in PW at high risk of TDM2. The patients were part of a 12-week training study (ClinicalTrials.gov Identifier: NCT03200639). Copyright © 2018 Elsevier Inc. All rights reserved.

Influence of acute exercise of varying intensity and duration on postprandial oxidative stress.

PubMed

Canale, Robert E; Farney, Tyler M; McCarthy, Cameron G; Bloomer, Richard J

2014-09-01

Aerobic exercise can reduce postprandial lipemia, and possibly oxidative stress, when performed prior to a lipid-rich meal. To compare the impact of acute exercise on postprandial oxidative stress. We compared aerobic and anaerobic exercise bouts of different intensities and durations on postprandial blood triglycerides (TAG), oxidative stress biomarkers (malondialdehyde, hydrogen peroxide, advanced oxidation protein products), and antioxidant status (trolox equivalent antioxidant capacity, superoxide dismutase, catalase, glutathione peroxidase). Twelve trained men (21-35 years) underwent four conditions: (1) No exercise rest; (2) 60-min aerobic exercise at 70% heart rate reserve; (3) five 60-s sprints at 100% max capacity; and (4) ten 15-s sprints at 200% max capacity. All exercise bouts were performed on a cycle ergometer. A high-fat meal was consumed 1 h after exercise cessation. Blood samples were collected pre-meal and 2 and 4 h post-meal and analyzed for TAG, oxidative stress biomarkers, and antioxidant status. No significant interaction or condition effects were noted for any variable (p > 0.05), with acute exercise having little to no effect on the magnitude of postprandial oxidative stress. In a sample of healthy, well-trained men, neither aerobic nor anaerobic exercise attenuates postprandial oxidative stress in response to a high-fat meal.

Randomized controlled trial of the effects of high intensity and low-to-moderate intensity exercise on physical fitness and fatigue in cancer survivors: results of the Resistance and Endurance exercise After ChemoTherapy (REACT) study.

PubMed

Kampshoff, Caroline S; Chinapaw, Mai J M; Brug, Johannes; Twisk, Jos W R; Schep, Goof; Nijziel, Marten R; van Mechelen, Willem; Buffart, Laurien M

2015-10-29

International evidence-based guidelines recommend physical exercise to form part of standard care for all cancer survivors. However, at present, the optimum exercise intensity is unclear. Therefore, we aimed to evaluate the effectiveness of a high intensity (HI) and low-to-moderate intensity (LMI) resistance and endurance exercise program compared with a wait list control (WLC) group on physical fitness and fatigue in a mixed group of cancer survivors who completed primary cancer treatment, including chemotherapy. Overall, 277 cancer survivors were randomized to 12 weeks of HI exercise (n = 91), LMI exercise (n = 95), or WLC (n = 91). Both interventions were identical with respect to exercise type, duration and frequency, and only differed in intensity. Measurements were performed at baseline (4-6 weeks after primary treatment) and post-intervention. The primary outcomes were cardiorespiratory fitness (peakVO2), muscle strength (grip strength and 30-second chair-stand test), and self-reported fatigue (Multidimensional Fatigue Inventory; MFI). Secondary outcomes included health-related quality of life, physical activity, daily functioning, body composition, mood, and sleep disturbances. Multilevel linear regression analyses were performed to estimate intervention effects using an intention-to-treat principle. In the HI and LMI groups, 74 % and 70 % of the participants attended more than 80 % of the prescribed exercise sessions, respectively (P = 0.53). HI (β = 2.2; 95 % CI, 1.2-3.1) and LMI (β = 1.3; 95 % CI, 0.3-2.3) exercise showed significantly larger improvements in peakVO2 compared to WLC. Improvements in peakVO2 were larger for HI than LMI exercise (β = 0.9; 95 % CI, -0.1 to 1.9), but the difference was not statistically significant (P = 0.08). No intervention effects were found for grip strength and the 30-second chair-stand test. HI and LMI exercise significantly reduced general and physical fatigue and reduced activity (MFI subscales) compared to WLC, with no significant differences between both interventions. Finally, compared to WLC, we found benefits in global quality of life and anxiety after HI exercise, improved physical functioning after HI and LMI exercise, and less problems at work after LMI exercise. Shortly after completion of cancer treatment, both HI and LMI exercise were safe and effective. There may be a dose-response relationship between exercise intensity and peakVO2, favoring HI exercise. HI and LMI exercise were equally effective in reducing general and physical fatigue. This study was registered at the Netherlands Trial Register [ NTR2153 ] on the 5th of January 2010.

Acute resistance exercise with blood flow restriction in elderly hypertensive women: haemodynamic, rating of perceived exertion and blood lactate.

PubMed

Pinto, Roberta R; Karabulut, Murat; Poton, Roberto; Polito, Marcos D

2018-01-01

This study aimed to compare haemodynamic, rating of perceived exertion and blood lactate responses during resistance exercise with blood flow restriction (BFR) compared with traditional high-intensity resistance exercise in hypertensive older women. Eighteen hypertensive women (age = 67·0 ± 1·7 years.) undertook three random sessions: (i) three sets; 10 repetitions; 20% of one repetition maximum (1RM) with BFR; (ii) three sets; 10 repetitions; 65% of 1RM; without BFR; and (iii) no-exercise with BFR. The exercise sessions were performed on knee extension equipment. Systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR), stroke volume (SV) and cardiac output (CO) were significantly higher (P<0·05) in all sets of exercise sessions than the control. No statistically significant differences were detected between exercise sessions. However, SBP, DBP and systemic vascular resistance were higher (P<0·05) and SV and CO were lower (P<0·05) during the rest intervals in the session with BFR. The perceived exertion was significantly higher (P<0·01) in the 1st (4·8 ± 0·4 versus 3·1 ± 0·3), 2nd (7·3 ± 0·4 versus 5·7 ± 0·4) and 3rd sets (8·6 ± 0·5 versus 7·5 ± 0·4) of the traditional high-intensity resistance exercise compared with the exercise with BFR. Blood lactate was higher (P<0·05) in the traditional high-intensity resistance exercise (6·2 ± 0·7 mmol) than in the exercise with BFR (4·5 ± 0·4 mmol). In comparison with high-intensity resistance exercise, low-intensity resistance exercise with BFR can elicit: (i) same haemodynamic values during exercise; (ii) lower rating of perceived exertion; (iii) lower blood lactate; (iv) higher haemodynamic demand during the rest intervals. © 2016 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Dietary nitrate supplementation improves team sport-specific intense intermittent exercise performance.

PubMed

Wylie, Lee J; Mohr, Magni; Krustrup, Peter; Jackman, Sarah R; Ermιdis, Georgios; Kelly, James; Black, Matthew I; Bailey, Stephen J; Vanhatalo, Anni; Jones, Andrew M

2013-07-01

Recent studies have suggested that dietary inorganic nitrate (NO₃(-)) supplementation may improve muscle efficiency and endurance exercise tolerance but possible effects during team sport-specific intense intermittent exercise have not been examined. We hypothesized that NO₃(-) supplementation would enhance high-intensity intermittent exercise performance. Fourteen male recreational team-sport players were assigned in a double-blind, randomized, crossover design to consume 490 mL of concentrated, nitrate-rich beetroot juice (BR) and nitrate-depleted placebo juice (PL) over ~30 h preceding the completion of a Yo-Yo intermittent recovery level 1 test (Yo-Yo IR1). Resting plasma nitrite concentration ([NO₂(-)]) was ~400% greater in BR compared to PL. Plasma [NO₂(-)] declined by 20% in PL (P < 0.05) and by 54 % in BR (P < 0.05) from pre-exercise to end-exercise. Performance in the Yo-Yo IR1 was 4.2% greater (P < 0.05) with BR (1,704 ± 304 m) compared to PL (1,636 ± 288 m). Blood [lactate] was not different between BR and PL, but the mean blood [glucose] was lower (3.8 ± 0.8 vs. 4.2 ± 1.1 mM, P < 0.05) and the rise in plasma [K(+)] tended to be reduced in BR compared to PL (P = 0.08). These findings suggest that NO₃(-) supplementation may promote NO production via the nitrate-nitrite-NO pathway and enhance Yo-Yo IR1 test performance, perhaps by facilitating greater muscle glucose uptake or by better maintaining muscle excitability. Dietary NO₃(-) supplementation improves performance during intense intermittent exercise and may be a useful ergogenic aid for team sports players.

Ryanodine receptor fragmentation and sarcoplasmic reticulum Ca2+ leak after one session of high-intensity interval exercise

PubMed Central

Place, Nicolas; Ivarsson, Niklas; Venckunas, Tomas; Neyroud, Daria; Brazaitis, Marius; Cheng, Arthur J.; Ochala, Julien; Kamandulis, Sigitas; Girard, Sebastien; Volungevičius, Gintautas; Paužas, Henrikas; Mekideche, Abdelhafid; Kayser, Bengt; Martinez-Redondo, Vicente; Bruton, Joseph; Truffert, Andre; Lanner, Johanna T.; Skurvydas, Albertas; Westerblad, Håkan

2015-01-01

High-intensity interval training (HIIT) is a time-efficient way of improving physical performance in healthy subjects and in patients with common chronic diseases, but less so in elite endurance athletes. The mechanisms underlying the effectiveness of HIIT are uncertain. Here, recreationally active human subjects performed highly demanding HIIT consisting of 30-s bouts of all-out cycling with 4-min rest in between bouts (≤3 min total exercise time). Skeletal muscle biopsies taken 24 h after the HIIT exercise showed an extensive fragmentation of the sarcoplasmic reticulum (SR) Ca2+ release channel, the ryanodine receptor type 1 (RyR1). The HIIT exercise also caused a prolonged force depression and triggered major changes in the expression of genes related to endurance exercise. Subsequent experiments on elite endurance athletes performing the same HIIT exercise showed no RyR1 fragmentation or prolonged changes in the expression of endurance-related genes. Finally, mechanistic experiments performed on isolated mouse muscles exposed to HIIT-mimicking stimulation showed reactive oxygen/nitrogen species (ROS)-dependent RyR1 fragmentation, calpain activation, increased SR Ca2+ leak at rest, and depressed force production due to impaired SR Ca2+ release upon stimulation. In conclusion, HIIT exercise induces a ROS-dependent RyR1 fragmentation in muscles of recreationally active subjects, and the resulting changes in muscle fiber Ca2+-handling trigger muscular adaptations. However, the same HIIT exercise does not cause RyR1 fragmentation in muscles of elite endurance athletes, which may explain why HIIT is less effective in this group. PMID:26575622

Ryanodine receptor fragmentation and sarcoplasmic reticulum Ca2+ leak after one session of high-intensity interval exercise.

PubMed

Place, Nicolas; Ivarsson, Niklas; Venckunas, Tomas; Neyroud, Daria; Brazaitis, Marius; Cheng, Arthur J; Ochala, Julien; Kamandulis, Sigitas; Girard, Sebastien; Volungevičius, Gintautas; Paužas, Henrikas; Mekideche, Abdelhafid; Kayser, Bengt; Martinez-Redondo, Vicente; Ruas, Jorge L; Bruton, Joseph; Truffert, Andre; Lanner, Johanna T; Skurvydas, Albertas; Westerblad, Håkan

2015-12-15

High-intensity interval training (HIIT) is a time-efficient way of improving physical performance in healthy subjects and in patients with common chronic diseases, but less so in elite endurance athletes. The mechanisms underlying the effectiveness of HIIT are uncertain. Here, recreationally active human subjects performed highly demanding HIIT consisting of 30-s bouts of all-out cycling with 4-min rest in between bouts (≤3 min total exercise time). Skeletal muscle biopsies taken 24 h after the HIIT exercise showed an extensive fragmentation of the sarcoplasmic reticulum (SR) Ca(2+) release channel, the ryanodine receptor type 1 (RyR1). The HIIT exercise also caused a prolonged force depression and triggered major changes in the expression of genes related to endurance exercise. Subsequent experiments on elite endurance athletes performing the same HIIT exercise showed no RyR1 fragmentation or prolonged changes in the expression of endurance-related genes. Finally, mechanistic experiments performed on isolated mouse muscles exposed to HIIT-mimicking stimulation showed reactive oxygen/nitrogen species (ROS)-dependent RyR1 fragmentation, calpain activation, increased SR Ca(2+) leak at rest, and depressed force production due to impaired SR Ca(2+) release upon stimulation. In conclusion, HIIT exercise induces a ROS-dependent RyR1 fragmentation in muscles of recreationally active subjects, and the resulting changes in muscle fiber Ca(2+)-handling trigger muscular adaptations. However, the same HIIT exercise does not cause RyR1 fragmentation in muscles of elite endurance athletes, which may explain why HIIT is less effective in this group.

A forced running wheel system with a microcontroller that provides high-intensity exercise training in an animal ischemic stroke model.

PubMed

Chen, C C; Chang, M W; Chang, C P; Chan, S C; Chang, W Y; Yang, C L; Lin, M T

2014-10-01

We developed a forced non-electric-shock running wheel (FNESRW) system that provides rats with high-intensity exercise training using automatic exercise training patterns that are controlled by a microcontroller. The proposed system successfully makes a breakthrough in the traditional motorized running wheel to allow rats to perform high-intensity training and to enable comparisons with the treadmill at the same exercise intensity without any electric shock. A polyvinyl chloride runway with a rough rubber surface was coated on the periphery of the wheel so as to permit automatic acceleration training, and which allowed the rats to run consistently at high speeds (30 m/min for 1 h). An animal ischemic stroke model was used to validate the proposed system. FNESRW, treadmill, control, and sham groups were studied. The FNESRW and treadmill groups underwent 3 weeks of endurance running training. After 3 weeks, the experiments of middle cerebral artery occlusion, the modified neurological severity score (mNSS), an inclined plane test, and triphenyltetrazolium chloride were performed to evaluate the effectiveness of the proposed platform. The proposed platform showed that enhancement of motor function, mNSS, and infarct volumes was significantly stronger in the FNESRW group than the control group (P<0.05) and similar to the treadmill group. The experimental data demonstrated that the proposed platform can be applied to test the benefit of exercise-preconditioning-induced neuroprotection using the animal stroke model. Additional advantages of the FNESRW system include stand-alone capability, independence of subjective human adjustment, and ease of use.

A forced running wheel system with a microcontroller that provides high-intensity exercise training in an animal ischemic stroke model

PubMed Central

Chen, C.C.; Chang, M.W.; Chang, C.P.; Chan, S.C.; Chang, W.Y.; Yang, C.L.; Lin, M.T.

2014-01-01

We developed a forced non-electric-shock running wheel (FNESRW) system that provides rats with high-intensity exercise training using automatic exercise training patterns that are controlled by a microcontroller. The proposed system successfully makes a breakthrough in the traditional motorized running wheel to allow rats to perform high-intensity training and to enable comparisons with the treadmill at the same exercise intensity without any electric shock. A polyvinyl chloride runway with a rough rubber surface was coated on the periphery of the wheel so as to permit automatic acceleration training, and which allowed the rats to run consistently at high speeds (30 m/min for 1 h). An animal ischemic stroke model was used to validate the proposed system. FNESRW, treadmill, control, and sham groups were studied. The FNESRW and treadmill groups underwent 3 weeks of endurance running training. After 3 weeks, the experiments of middle cerebral artery occlusion, the modified neurological severity score (mNSS), an inclined plane test, and triphenyltetrazolium chloride were performed to evaluate the effectiveness of the proposed platform. The proposed platform showed that enhancement of motor function, mNSS, and infarct volumes was significantly stronger in the FNESRW group than the control group (P<0.05) and similar to the treadmill group. The experimental data demonstrated that the proposed platform can be applied to test the benefit of exercise-preconditioning-induced neuroprotection using the animal stroke model. Additional advantages of the FNESRW system include stand-alone capability, independence of subjective human adjustment, and ease of use. PMID:25140816

Study in Parkinson Disease of Exercise (SPARX): Translating high-intensity exercise from animals to humans

PubMed Central

Moore, Charity G.; Schenkman, Margaret; Kohrt, Wendy M.; Delitto, Anthony; Hall, Deborah A.; Corcos, Daniel

2013-01-01

A burgeoning literature suggests that exercise has a therapeutic benefit in persons with Parkinson disease (PD) and in animal models of PD, especially when animals exercise at high intensity. If exercise is to be prescribed as “first-line” or “add-on” therapy in patients with PD, we must demonstrate its efficacy and dose-response effects through testing phases similar to those used in the testing of pharmacologic agents. The SPARX Trial is a multicenter, randomized, controlled, single-blinded, Phase II study that we designed to test the feasibility of using high-intensity exercise to modify symptoms of PD and to simultaneously test the nonfutility of achieving a prespecified change in patients’ motor scores on the Unified Parkinson Disease Rating Scale (UPDRS). The trial began in May 2102 and is in the process of screening, enrolling, and randomly assigning 126 patients with early-stage PD to 1 of 3 groups: usual care (wait-listed controls), moderate-intensity exercise (4 days/week at 60%–65% maximal heart rate [HRmax]), or high-intensity exercise (4 days/week at 80%–85% HRmax). At 6-month follow-up, the trial is randomly reassigning usual care participants to a moderate-intensity or high-intensity exercise group for the remaining 6 months. The goals of the Phase II trial are to determine if participants can exercise at moderate and high intensities; to determine if either exercise yields benefits consistent with meaningful clinical change (nonfutility); and to document safety and attrition. The advantage of using a non-futility approach allows us to efficiently determine if moderate- or high-intensity exercise warrants further large-scale investigation in PD. PMID:23770108

Physiological responses of young thoroughbred horses to intermittent high-intensity treadmill training

PubMed Central

2013-01-01

Background Training of young Thoroughbred horses must balance development of cardiopulmonary function and aerobic capacity with loading of the musculoskeletal system that can potentially cause structural damage and/or lameness. High-speed equine treadmills are sometimes used to supplement exercise on a track in the training of young Thoroughbreds because the horse can run at high speeds but without the added weight of a rider. We tested the hypothesis that intermittent high-intensity exercise on a treadmill of young Thoroughbred horses entering training can enhance development of aerobic capacity (Vo2max) and running performance more than conventional training under saddle, and do so without causing lameness. Results Twelve yearling Thoroughbreds trained for 8 months with conventional riding (C) only, conventional riding plus a short (2 month, S) interval of once-per-week high-intensity treadmill exercise, or a long (8 month, L) interval of once-per-week high-intensity treadmill exercise. Three treadmill exercise tests evaluated Vo2max, oxygen transport and running performance variables in June of the yearling year (only for L), October of the yearling year and April of the 2-year-old year. No horses experienced lameness during the study. Aerobic capacity increased in all groups after training. In both October and April, Vo2max in L was higher than in C, but did not differ between L and S or S and C. Running speeds eliciting Vo2max also increased in all groups after training, with S (809 ± 3 m/s) and L (804 ± 9 m/s) higher than C (764 ± 27 m/s). Maximum heart rate decreased for all groups after training. Hematocrit and hemoglobin concentration increased for L throughout training. Conclusions Young Thoroughbred horses can increase aerobic capacity and running performance more than by strictly using track training under saddle with the addition of intermittent high-intensity treadmill exercise, and they can do so without experiencing lameness. This finding suggests that young racehorses might be able to achieve higher aerobic fitness during training without subjecting their musculoskeletal systems to increased loading and risk of developing lameness. The findings of this preliminary study do not indicate a specific protocol to best achieve this goal. PMID:23957961

Effect of carbohydrate-electrolyte consumption on insulin, cortisol hormones and blood glucose after high-intensity exercise.

PubMed

Mor, Ahmet; Kayacan, Yildirim; Ipekoglu, Gokhan; Arslanoglu, Erkal

2018-04-21

This study aimed to examine the effect of CHO-E consumption after high-intensity exercise on insulin, cortisol hormones and blood glucose responses, which is important for performance and recovery in athletes. Sixteen volunteers, male athletes, participated into this study. Athletes were divided into two groups as experiment (CHO-E) and placebo (PLA). Blood was taken from the athletes three times as basal, post-exercise (PE) and 2 h after ingestion of supplement (PS). When inter-group comparisons, insulin was significantly higher in the CHO-E group than the PLA group at the PS phase (p < .05). Cortisol significantly decreased in the CHO-E group at the PS compared to the PE (p < .05). Carbohydrate-electrolyte consumption after high-intensity exercise, accelerates the recovery process by providing optimal recovery, and enable the metabolism to remain in the anabolic state by preventing it from entering in the catabolic process as well as provides hormonal balance in metabolism.

Acute and Post-Exercise Physiological Responses to High-Intensity Interval Training in Endurance and Sprint Athletes

PubMed Central

Cipryan, Lukas; Tschakert, Gerhard; Hofmann, Peter

2017-01-01

The purpose of the presented study was to compare acute and post-exercise differences in cardiorespiratory, metabolic, cardiac autonomic, inflammatory and muscle damage responses to high-intensity interval exercise (HIIT) between endurance and sprint athletes. The study group consisted of sixteen highly-trained males (age 22.1 ± 2.5 years) participating in endurance (n = 8) or sprint (n = 8) sporting events. All the participants underwent three exercise sessions: short HIIT (work interval duration 30s), long HIIT (3min) and constant load exercise (CE). The exercise interventions were matched for mean power, total time and in case of HIIT interventions also for work-to-relief ratio. The acute cardiorespiratory (HR, V̇O2, RER) and metabolic (lactate) variables as well as the post-exercise changes (up to 3 h) in the heart rate variability, inflammation (interleukin-6, leucocytes) and muscle damage (creatine kinase, myoglobin) were monitored. Endurance athletes performed exercise interventions with moderately (CE) or largely (both HIIT modes) higher mean V̇O2. These differences were trivial/small when V̇O2 was expressed as a percentage of V̇O2max. Moderately to largely lower RER and lactate values were found in endurance athletes. Markers of cardiac autonomic regulation, inflammation and muscle damage did not reveal any considerable differences between endurance and sprint athletes. In conclusions, endurance athletes were able to perform both HIIT formats with increased reliance on aerobic metabolic pathways although exercise intensity was identical in relative terms for all the participants. However, other markers of the acute and early post-exercise physiological response to these HIIT interventions indicated similarities between endurance and sprint athletes. Key points The manner in which each training background (endurance vs. sprint) influences the response to HIIT is not well known. Despite the identical exercise intensity in relative terms, endurance athletes are able to perform HIIT with increased reliance on aerobic metabolic pathways when compared to sprint athletes. The mean V̇O2 (% V̇O2max) and HR as well as markers of the cardiac autonomic regulation, systemic inflammation and muscle damage monitored during the early recovery phase did not demonstrate any differences between endurance and sprint trained individuals. PMID:28630575

The effect of α1 -adrenergic blockade on post-exercise brachial artery flow-mediated dilatation at sea level and high altitude.

PubMed

Tymko, Michael M; Tremblay, Joshua C; Hansen, Alex B; Howe, Connor A; Willie, Chris K; Stembridge, Mike; Green, Daniel J; Hoiland, Ryan L; Subedi, Prajan; Anholm, James D; Ainslie, Philip N

2017-03-01

Our objective was to quantify endothelial function (via brachial artery flow-mediated dilatation) at sea level (344 m) and high altitude (3800 m) at rest and following both maximal exercise and 30 min of moderate-intensity cycling exercise with and without administration of an α 1 -adrenergic blockade. Brachial endothelial function did not differ between sea level and high altitude at rest, nor following maximal exercise. At sea level, endothelial function decreased following 30 min of moderate-intensity exercise, and this decrease was abolished with α 1 -adrenergic blockade. At high altitude, endothelial function did not decrease immediately after 30 min of moderate-intensity exercise, and administration of α 1 -adrenergic blockade resulted in an increase in flow-mediated dilatation. Our data indicate that post-exercise endothelial function is modified at high altitude (i.e. prolonged hypoxaemia). The current study helps to elucidate the physiological mechanisms associated with high-altitude acclimatization, and provides insight into the relationship between sympathetic nervous activity and vascular endothelial function. We examined the hypotheses that (1) at rest, endothelial function would be impaired at high altitude compared to sea level, (2) endothelial function would be reduced to a greater extent at sea level compared to high altitude after maximal exercise, and (3) reductions in endothelial function following moderate-intensity exercise at both sea level and high altitude are mediated via an α 1 -adrenergic pathway. In a double-blinded, counterbalanced, randomized and placebo-controlled design, nine healthy participants performed a maximal-exercise test, and two 30 min sessions of semi-recumbent cycling exercise at 50% peak output following either placebo or α 1 -adrenergic blockade (prazosin; 0.05 mg kg  -1 ). These experiments were completed at both sea-level (344 m) and high altitude (3800 m). Blood pressure (finger photoplethysmography), heart rate (electrocardiogram), oxygen saturation (pulse oximetry), and brachial artery blood flow and shear rate (ultrasound) were recorded before, during and following exercise. Endothelial function assessed by brachial artery flow-mediated dilatation (FMD) was measured before, immediately following and 60 min after exercise. Our findings were: (1) at rest, FMD remained unchanged between sea level and high altitude (placebo P = 0.287; prazosin: P = 0.110); (2) FMD remained unchanged after maximal exercise at sea level and high altitude (P = 0.244); and (3) the 2.9 ± 0.8% (P = 0.043) reduction in FMD immediately after moderate-intensity exercise at sea level was abolished via α 1 -adrenergic blockade. Conversely, at high altitude, FMD was unaltered following moderate-intensity exercise, and administration of α 1 -adrenergic blockade elevated FMD (P = 0.032). Our results suggest endothelial function is differentially affected by exercise when exposed to hypobaric hypoxia. These findings have implications for understanding the chronic impacts of hypoxaemia on exercise, and the interactions between the α 1 -adrenergic pathway and endothelial function. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Morning bright light exposure has no influence on self-chosen exercise intensity and mood in overweight individuals - A randomized controlled trial.

PubMed

Knaier, Raphael; Klenk, Christopher; Königstein, Karsten; Hinrichs, Timo; Rossmeissl, Anja; Infanger, Denis; Cajochen, Christian; Schmidt-Trucksäss, Arno

2018-04-01

Overweight is a worldwide increasing public health issue. Physical exercise is a useful countermeasure. Overweight individuals choose rather low exercise intensities, but especially high exercise intensities lead to higher energy expenditure and show beneficial health effects compared to lower exercise intensities. However, especially in the morning higher exercise intensities are likely to be avoided due to higher subjective effort. Bright light exposure has shown to increase maximum performance. The aim of this study was to investigate if bright light exposure can also increase self-chosen exercise intensity. We hypothesized that morning bright light exposure increases self-chosen exercise intensity of subsequent exercise through increased mood and reduced sleepiness in overweight individuals. In this randomized controlled single-blind parallel group design, 26 overweight individuals (11 males, 15 females; age 25 ± 5.7 years; body mass index 28.9 ± 2.1 kg/m 2 ) underwent three measurement appointments. On the first appointment, subjects performed a cardiopulmonary exercise test to measure maximum oxygen uptake (VO2max). Two days later a 30-min exercise session with self-chosen exercise intensity was performed for familiarization. Then subjects were randomly allocated to bright light (~4400 lx) or a control light (~230 lx) condition. Three to seven days later, subjects were exposed to light for 30 min starting at 8:00 am, immediately followed by a 30-min exercise session with persisting light exposure. Multidimensional mood questionnaires were filled out before and after the light exposure and after the exercise session. The primary outcome was the mean power output during the exercise session and the secondary outcome the rating on the three domains (i.e. good-bad; awake-tired; calm-nervous) of the multidimensional mood questionnaire. Mean power output during the exercise session was 92 ± 19 W in bright light and 80 ± 37 W in control light, respectively. In the multivariate analysis adjusted for VO2max, the mean power output during the exercise session was 8.5 W higher (95% confidence interval -12.7, 29.7; p = 0.416) for participants in bright light compared to control light. There were no significant differences between the groups for any of the three domains of the questionnaire at any time point. This is in contrast to longer lasting intervention studies that show positive influences on mood and suggests that bright light therapy requires repetitive sessions to improve mood in overweight individuals. In conclusion bright light exposure does not acutely increase self-chosen exercise intensity or improve mood in a 30-min exercise session starting at 08:30. However, regarding the fact that overweight is a worldwide and rapidly increasing public health issue even small increases in exercise intensity may be relevant. The trend toward superiority of bright light over control light implicates that further studies may be conducted in a larger scale. VO2max: maximum oxygen uptake; 95% CI: 95% confidence interval; SD: standard deviation.

Acute effects of high- and low-intensity exercise bouts on leukocyte counts.

PubMed

Neves, Pedro Rogério Da Silva; Tenório, Thiago Ricardo Dos Santos; Lins, Tatiana Acioli; Muniz, Maria Tereza Cartaxo; Pithon-Curi, Tânia Cristina; Botero, João Paulo; Do Prado, Wagner Luiz

2015-06-01

It is widely accepted that physical exercise may bring about changes in the immune system. Even acute bouts of exercise can alter the number and function of leukocytes, but the degree of white blood cell trafficking depends on the intensity and duration of exercise. The aim of this study was to analyze the acute and short-term effects of exercise intensity on leukocyte counts and leukocyte subsets. Nine physically healthy, active young males (21.0 ± 1.9 years) underwent three experimental trials: high exercise intensity [80% peak oxygen consumption (VO 2peak )], low exercise intensity (40% VO 2peak ), and the control condition (no exercise). Blood samples were collected prior to exercise, immediately after exercise, and 2 hours after exercise. Two-way analysis of variance for repeated measures was used to evaluate differences between the trials and the time-points, and to compare times within trials. There was a greater increase in the leukocyte count after high-intensity exercise, compared to the control condition ( p  < 0.01) and low-intensity exercise ( p  < 0.01). This effect was still present 2 hours after passive recovery ( p  < 0.01). When the same participants were submitted to different exercise intensities, the acute and short-term effects of exercise on white blood cells were intensity-dependent immediately after exercise (i.e., lymphocytosis and monocytosis) and 2 hours after passive recovery (i.e., neutrophilia).

Effects of a high-intensity interval training program versus a moderate-intensity continuous training program on maximal oxygen uptake and blood pressure in healthy adults: study protocol for a randomized controlled trial.

PubMed

Arboleda Serna, Víctor Hugo; Arango Vélez, Elkin Fernando; Gómez Arias, Rubén Darío; Feito, Yuri

2016-08-18

Participation in aerobic exercise generates increased cardiorespiratory fitness, which results in a protective factor for cardiovascular disease and all-cause mortality. High-intensity interval training might cause higher increases in cardiorespiratory fitness in comparison with moderate-intensity continuous training; nevertheless, current evidence is not conclusive. To our knowledge, this is the first study to test the effect of high-intensity interval training with total load duration of 7.5 min per session. A randomized controlled trial will be performed on two groups of healthy, sedentary male volunteers (n = 44). The study protocol will include 24 exercise sessions, three times a week, including aerobic training on a treadmill and strength training exercises. The intervention group will perform 15 bouts of 30 s, each at an intensity between 90 % and 95 % of maximal heart rate. The control group will complete 40 min of continuous exercise, ranging between 65 % and 75 % of maximal heart rate. The primary outcome measure to be evaluated will be maximal oxygen uptake (VO2max), and systolic and diastolic blood pressure will be evaluated as secondary outcome measures. Waist circumference, body mass index, and body composition will also be evaluated. Epidemiological evidence shows the link between VO2max and its association with chronic conditions that trigger CVD. Therefore, finding ways to improve VO2max and reduce blood pressure it is of vital importance to public health. NCT02288403 . Registered on 4 November 2014.

Potassium kinetics in human muscle interstitium during repeated intense exercise in relation to fatigue.

PubMed

Mohr, Magni; Nordsborg, Nikolai; Nielsen, Jens Jung; Pedersen, Lasse Danneman; Fischer, Christian; Krustrup, Peter; Bangsbo, Jens

2004-07-01

Accumulation of K+ in skeletal muscle interstitium during intense exercise has been suggested to cause fatigue in humans. The present study examined interstitial K+ kinetics and fatigue during repeated, intense, exhaustive exercise in human skeletal muscle. Ten subjects performed three repeated, intense (61.6+/-4.1 W; mean+/-SEM), one-legged knee extension exercise bouts (EX1, EX2 and EX3) to exhaustion separated by 10-min recovery periods. Interstitial [K+] ([K+]interst) in the vastus lateralis muscle were determined using microdialysis. Time-to-fatigue decreased progressively (P<0.05) during the protocol (5.1+/-0.4, 4.2+/-0.3 and 3.2+/-0.2 min for EX1, EX2 and EX3 respectively). Prior to these bouts, [K+]interst was 4.1+/-0.2, 4.8+/-0.2 and 5.2+/-0.2 mM, respectively. During the initial 1.5 min of exercise the accumulation rate of interstitial K+ was 85% greater (P<0.05) in EX1 than in EX3. At exhaustion [K+]interst was 11.4+/-0.8 mM in EX1, which was not different from that in EX2 (10.4+/-0.8 mM), but higher (P<0.05) than in EX3 (9.1+/-0.3 mM). The study demonstrated that the rate of accumulation of K+ in the muscle interstitium declines during intense repetitive exercise. Furthermore, whilst [K+]interst at exhaustion reached levels high enough to impair performance, the concentration decreased with repeated exercise, suggesting that accumulation of interstitial K+ per se does not cause fatigue when intense exercise is repeated.

The use of carbohydrates during exercise as an ergogenic aid.

PubMed

Cermak, Naomi M; van Loon, Luc J C

2013-11-01

Carbohydrate and fat are the two primary fuel sources oxidized by skeletal muscle tissue during prolonged (endurance-type) exercise. The relative contribution of these fuel sources largely depends on the exercise intensity and duration, with a greater contribution from carbohydrate as exercise intensity is increased. Consequently, endurance performance and endurance capacity are largely dictated by endogenous carbohydrate availability. As such, improving carbohydrate availability during prolonged exercise through carbohydrate ingestion has dominated the field of sports nutrition research. As a result, it has been well-established that carbohydrate ingestion during prolonged (>2 h) moderate-to-high intensity exercise can significantly improve endurance performance. Although the precise mechanism(s) responsible for the ergogenic effects are still unclear, they are likely related to the sparing of skeletal muscle glycogen, prevention of liver glycogen depletion and subsequent development of hypoglycemia, and/or allowing high rates of carbohydrate oxidation. Currently, for prolonged exercise lasting 2-3 h, athletes are advised to ingest carbohydrates at a rate of 60 g·h⁻¹ (~1.0-1.1 g·min⁻¹) to allow for maximal exogenous glucose oxidation rates. However, well-trained endurance athletes competing longer than 2.5 h can metabolize carbohydrate up to 90 g·h⁻¹ (~1.5-1.8 g·min⁻¹) provided that multiple transportable carbohydrates are ingested (e.g. 1.2 g·min⁻¹ glucose plus 0.6 g·min⁻¹ of fructose). Surprisingly, small amounts of carbohydrate ingestion during exercise may also enhance the performance of shorter (45-60 min), more intense (>75 % peak oxygen uptake; VO(₂peak)) exercise bouts, despite the fact that endogenous carbohydrate stores are unlikely to be limiting. The mechanism(s) responsible for such ergogenic properties of carbohydrate ingestion during short, more intense exercise bouts has been suggested to reside in the central nervous system. Carbohydrate ingestion during exercise also benefits athletes involved in intermittent/team sports. These athletes are advised to follow similar carbohydrate feeding strategies as the endurance athletes, but need to modify exogenous carbohydrate intake based upon the intensity and duration of the game and the available endogenous carbohydrate stores. Ample carbohydrate intake is also important for those athletes who need to compete twice within 24 h, when rapid repletion of endogenous glycogen stores is required to prevent a decline in performance. To support rapid post-exercise glycogen repletion, large amounts of exogenous carbohydrate (1.2 g·kg⁻¹·h⁻¹) should be provided during the acute recovery phase from exhaustive exercise. For those athletes with a lower gastrointestinal threshold for carbohydrate ingestion immediately post-exercise, and/or to support muscle re-conditioning, co-ingesting a small amount of protein (0.2-0.4 g·kg⁻¹·h⁻¹) with less carbohydrate (0.8 g·kg⁻¹·h⁻¹) may provide a feasible option to achieve similar muscle glycogen repletion rates.

Muscle and intensity based hamstring exercise classification in elite female track and field athletes: implications for exercise selection during rehabilitation

PubMed Central

Tsaklis, Panagiotis; Malliaropoulos, Nikos; Mendiguchia, Jurdan; Korakakis, Vasileios; Tsapralis, Kyriakos; Pyne, Debasish; Malliaras, Peter

2015-01-01

Background Hamstring injuries are common in many sports, including track and field. Strains occur in different parts of the hamstring muscle but very little is known about whether common hamstring loading exercises specifically load different hamstring components. The purpose of this study was to investigate muscle activation of different components of the hamstring muscle during common hamstring loading exercises. Methods Twenty elite female track and field athletes were recruited into this study, which had a single-sample, repeated-measures design. Each athlete performed ten hamstring loading exercises, and an electromyogram (EMG) was recorded from the biceps femoris and semitendinosus components of the hamstring. Hamstring EMG during maximal voluntary isometric contraction (MVIC) was used to normalize the mean data across ten repetitions of each exercise. An electrogoniometer synchronized to the EMG was used to determine whether peak EMG activity occurred during muscle-tendon unit lengthening, shortening, or no change in length. Mean EMG values were compared between the two recording sites for each exercise using the Student’s t-test. Results The lunge, dead lift, and kettle swings were low intensity (<50% MVIC) and all showed higher EMG activity for semitendinosus than for biceps femoris. Bridge was low but approaching medium intensity, and the TRX, hamstring bridge, and hamstring curl were all medium intensity exercises (≥50% or <80% MVIC). The Nordic, fitball, and slide leg exercises were all high intensity exercises. Only the fitball exercise showed higher EMG activity in the biceps femoris compared with the semitendinosus. Only lunge and kettle swings showed peak EMG in the muscle-tendon unit lengthening phase and both these exercises involved faster speed. Conclusion Some exercises selectively activated the lateral and medial distal hamstrings. Low, medium, and high intensity exercises were demonstrated. This information enables the clinician, strength and conditioning coach and physiotherapist to better understand intensity- and muscle-specific activation during hamstring muscle rehabilitation. Therefore, these results may help in designing progressive strengthening and rehabilitation and prevention programs. PMID:26170726

Effects of high-intensity interval versus continuous exercise training on post-exercise heart rate recovery in coronary heart-disease patients.

PubMed

Villelabeitia-Jaureguizar, Koldobika; Vicente-Campos, Davinia; Senen, Alejandro Berenguel; Jiménez, Verónica Hernández; Garrido-Lestache, María Elvira Barrios; Chicharro, Jose López

2017-10-01

Heart rate recovery (HRR) has been considered a prognostic and mortality indicator in both healthy and coronary patients. Physical exercise prescription has shown improvements in VO 2 peak and HRR, but most of the studies have been carried out applying continuous training at a moderate intensity, being very limited the use of protocols of high intensity interval training in coronary patients. We aimed to compare the effects of a moderate continuous training (MCT) versus a high intensity interval training (HIIT) programme on VO 2 peak and HRR. Seventy three coronary patients were assigned to either HIIT or MCT groups for 8weeks. Incremental exercise tests in a cycloergometer were performed to obtain VO 2 peak data and heart rate was monitored during and after the exercise test to obtain heart rate recovery data. Both exercise programmes significantly increase VO 2 peak with a higher increase in the HIIT group (HIIT: 4.5±4.46ml/kg/min vs MCT: 2.46±3.57ml/kg/min; p=0.039). High intensity interval training resulted in a significantly increase in HRR at the first and second minute of the recovery phase (15,44±7,04 vs 21,22±6,62, p<0,0001 and 23,73±9,64 vs 31,52±8,02, p<0,0001, respectively). The results of our research show that the application of HIIT to patients with chronic ischemic heart disease of low risk resulted in an improvement in VO 2 peak, and also improvements in post-exercise heart-rate recovery, compared with continuous training. Copyright © 2017 Elsevier B.V. All rights reserved.

The effect of α1‐adrenergic blockade on post‐exercise brachial artery flow‐mediated dilatation at sea level and high altitude

PubMed Central

Tremblay, Joshua C.; Hansen, Alex B.; Howe, Connor A.; Willie, Chris K.; Stembridge, Mike; Green, Daniel J.; Hoiland, Ryan L.; Subedi, Prajan; Anholm, James D.; Ainslie, Philip N.

2016-01-01

Key points Our objective was to quantify endothelial function (via brachial artery flow‐mediated dilatation) at sea level (344 m) and high altitude (3800 m) at rest and following both maximal exercise and 30 min of moderate‐intensity cycling exercise with and without administration of an α1‐adrenergic blockade.Brachial endothelial function did not differ between sea level and high altitude at rest, nor following maximal exercise.At sea level, endothelial function decreased following 30 min of moderate‐intensity exercise, and this decrease was abolished with α1‐adrenergic blockade. At high altitude, endothelial function did not decrease immediately after 30 min of moderate‐intensity exercise, and administration of α1‐adrenergic blockade resulted in an increase in flow‐mediated dilatation.Our data indicate that post‐exercise endothelial function is modified at high altitude (i.e. prolonged hypoxaemia). The current study helps to elucidate the physiological mechanisms associated with high‐altitude acclimatization, and provides insight into the relationship between sympathetic nervous activity and vascular endothelial function. Abstract We examined the hypotheses that (1) at rest, endothelial function would be impaired at high altitude compared to sea level, (2) endothelial function would be reduced to a greater extent at sea level compared to high altitude after maximal exercise, and (3) reductions in endothelial function following moderate‐intensity exercise at both sea level and high altitude are mediated via an α1‐adrenergic pathway. In a double‐blinded, counterbalanced, randomized and placebo‐controlled design, nine healthy participants performed a maximal‐exercise test, and two 30 min sessions of semi‐recumbent cycling exercise at 50% peak output following either placebo or α1‐adrenergic blockade (prazosin; 0.05 mg kg −1). These experiments were completed at both sea‐level (344 m) and high altitude (3800 m). Blood pressure (finger photoplethysmography), heart rate (electrocardiogram), oxygen saturation (pulse oximetry), and brachial artery blood flow and shear rate (ultrasound) were recorded before, during and following exercise. Endothelial function assessed by brachial artery flow‐mediated dilatation (FMD) was measured before, immediately following and 60 min after exercise. Our findings were: (1) at rest, FMD remained unchanged between sea level and high altitude (placebo P = 0.287; prazosin: P = 0.110); (2) FMD remained unchanged after maximal exercise at sea level and high altitude (P = 0.244); and (3) the 2.9 ± 0.8% (P = 0.043) reduction in FMD immediately after moderate‐intensity exercise at sea level was abolished via α1‐adrenergic blockade. Conversely, at high altitude, FMD was unaltered following moderate‐intensity exercise, and administration of α1‐adrenergic blockade elevated FMD (P = 0.032). Our results suggest endothelial function is differentially affected by exercise when exposed to hypobaric hypoxia. These findings have implications for understanding the chronic impacts of hypoxaemia on exercise, and the interactions between the α1‐adrenergic pathway and endothelial function. PMID:28032333

Electromyographic analyses of muscle pre-activation induced by single joint exercise.

PubMed

Júnior, Valdinar A R; Bottaro, Martim; Pereira, Maria C C; Andrade, Marcelino M; P Júnior, Paulo R W; Carmo, Jake C

2010-01-01

To investigate whether performing a low-intensity, single-joint exercises for knee extensors was an efficient strategy for increasing the number of motor units recruited in the vastus lateralis muscle during a subsequent multi-joint exercises. Nine healthy male participants (23.33+/-3.46 yrs) underwent bouts of exercise in which knee extension and 45 degrees , and leg press exercises were performed in sequence. In the low-intensity bout (R30), 15 unilateral knee extensions were performed, followed by 15 repetitions of the leg presses at 30% and 60% of one maximum repetition load (1-MR), respectively. In the high-intensity bout (R60), the same sequence was performed, but the applied load was 60% of 1-MR for both exercises. A single set of 15 repetitions of the leg press at 60% of 1-MR was performed as a control exercise (CR). The surface electromyographic signals of the vastus lateralis muscle were recorded by means of a linear electrode array. The root mean square (RMS) values were determined for each repetition of the leg press, and linear regressions were calculated from these results. The slopes of the straight lines obtained were then normalized using the linear coefficients of the regression equations and compared using one-way ANOVAs for repeated measures. The slopes observed in the CR were significantly lower than those in the R30 and R60 (p<0.05). The results indicated that the recruitment of motor units was more effective when a single-joint exercise preceded the multi-joint exercise. Article registered in the Australian New Zealand Clinical Trials Registry (ANZCTR) under the number ACTRN12609000413224.

Effect of Exercise Intensity on Neurotrophic Factors and Blood-Brain Barrier Permeability Induced by Oxidative-Nitrosative Stress in Male College Students.

PubMed

Roh, Hee-Tae; Cho, Su-Youn; Yoon, Hyung-Gi; So, Wi-Young

2017-06-01

We investigated the effects of aerobic exercise intensity on oxidative-nitrosative stress, neurotrophic factor expression, and blood-brain barrier (BBB) permeability. Fifteen healthy men performed treadmill running under low-intensity (LI), moderate-intensity (MI), and high-intensity (HI) conditions. Blood samples were collected immediately before exercise (IBE), immediately after exercise (IAE), and 60 min after exercise (60MAE) to examine oxidative-nitrosative stress (reactive oxygen species [ROS]; nitric oxide [NO]), neurotrophic factors (brain-derived neurotrophic factor [BDNF]; nerve growth factor [NGF]), and blood-brain barrier (BBB) permeability (S-100β; neuron-specific enolase). ROS concentration significantly increased IAE and following HI (4.9 ± 1.7 mM) compared with that after LI (2.8 ± 1.4 mM) exercise (p < .05). At 60MAE, ROS concentration was higher following HI (2.5 ± 1.2 mM) than after LI (1.5 ± 0.5 mM) and MI (1.4 ± 0.3 mM) conditions (p < .05). Plasma NO IAE increased significantly after MI and HI exercise (p < .05). Serum BDNF, NGF, and S-100b levels were significantly higher IAE following MI and HI exercise (p < .05). BDNF and S-100b were higher IAE following MI (29.6 ± 3.4 ng/mL and 87.1 ± 22.8 ng/L, respectively) and HI (31.4 ± 3.8 ng/mL and 100.6 ± 21.2 ng/L, respectively) than following LI (26.5 ± 3.0 ng/mL and 64.8 ± 19.2 ng/L, respectively) exercise (p < .05). 60MAE, S-100b was higher following HI (71.1 ± 14.5 ng/L) than LI (56.2 ± 14.7 ng/L) exercise (p < .05). NSE levels were not significantly different among all intensity conditions and time points (p > .05). Moderate- and/or high-intensity exercise may induce higher oxidative-nitrosative stress than may low-intensity exercise, which can increase peripheral neurotrophic factor levels by increasing BBB permeability.

Is high-intensity interval training a time-efficient exercise strategy to improve health and fitness?

PubMed

Gillen, Jenna B; Gibala, Martin J

2014-03-01

Growing research suggests that high-intensity interval training (HIIT) is a time-efficient exercise strategy to improve cardiorespiratory and metabolic health. "All out" HIIT models such as Wingate-type exercise are particularly effective, but this type of training may not be safe, tolerable or practical for many individuals. Recent studies, however, have revealed the potential for other models of HIIT, which may be more feasible but are still time-efficient, to stimulate adaptations similar to more demanding low-volume HIIT models and high-volume endurance-type training. As little as 3 HIIT sessions per week, involving ≤10 min of intense exercise within a time commitment of ≤30 min per session, including warm-up, recovery between intervals and cool down, has been shown to improve aerobic capacity, skeletal muscle oxidative capacity, exercise tolerance and markers of disease risk after only a few weeks in both healthy individuals and people with cardiometabolic disorders. Additional research is warranted, as studies conducted have been relatively short-term, with a limited number of measurements performed on small groups of subjects. However, given that "lack of time" remains one of the most commonly cited barriers to regular exercise participation, low-volume HIIT is a time-efficient exercise strategy that warrants consideration by health practitioners and fitness professionals.

In dubio pro silentio – Even Loud Music Does Not Facilitate Strenuous Ergometer Exercise

PubMed Central

Kreutz, Gunter; Schorer, Jörg; Sojke, Dominik; Neugebauer, Judith; Bullack, Antje

2018-01-01

Background: Music listening is wide-spread in amateur sports. Ergometer exercise is one such activity which is often performed with loud music. Aim and Hypotheses: We investigated the effects of electronic music at different intensity levels on ergometer performance (physical performance, force on the pedal, pedaling frequency), perceived fatigue and heart rate in healthy adults. We assumed that higher sound intensity levels are associated with greater ergometer performance and less perceived effort, particularly for untrained individuals. Methods: Groups of high trained and low trained healthy males (N = 40; age = 25.25 years; SD = 3.89 years) were tested individually on an ergometer while electronic dance music was played at 0, 65, 75, and 85 dB. Participants assessed their music experience during the experiment. Results: Majorities of participants rated the music as not too loud (65%), motivating (77.50%), appropriate for this sports exercise (90%), and having the right tempo (67.50%). Participants noticed changes in the acoustical environment with increasing intensity levels, but no further effects on any of the physical or other subjective measures were found for neither of the groups. Therefore, the main hypothesis must be rejected. Discussion: These findings suggest that high loudness levels do not positively influence ergometer performance. The high acceptance of loud music and perceived appropriateness could be based on erroneous beliefs or stereotypes. Reasons for the widespread use of loud music in fitness sports needs further investigation. Reducing loudness during fitness exercise may not compromise physical performance or perceived effort. PMID:29867622

Improving performance in golf: current research and implications from a clinical perspective.

PubMed

Evans, Kerrie; Tuttle, Neil

2015-01-01

Golf, a global sport enjoyed by people of all ages and abilities, involves relatively long periods of low intensity exercise interspersed with short bursts of high intensity activity. To meet the physical demands of full swing shots and the mental and physical demands of putting and walking the course, it is frequently recommended that golfers undertake golf-specific exercise programs. Biomechanics, motor learning, and motor control research has increased the understanding of the physical requirements of the game, and using this knowledge, exercise programs aimed at improving golf performance have been developed. However, while it is generally accepted that an exercise program can improve a golfer's physical measurements and some golf performance variables, translating the findings from research into clinical practice to optimise an individual golfer's performance remains challenging. This paper discusses how biomechanical and motor control research has informed current practice and discusses how emerging sophisticated tools and research designs may better assist golfers improve their performance.

Improving performance in golf: current research and implications from a clinical perspective

PubMed Central

Evans, Kerrie; Tuttle, Neil

2015-01-01

Golf, a global sport enjoyed by people of all ages and abilities, involves relatively long periods of low intensity exercise interspersed with short bursts of high intensity activity. To meet the physical demands of full swing shots and the mental and physical demands of putting and walking the course, it is frequently recommended that golfers undertake golf-specific exercise programs. Biomechanics, motor learning, and motor control research has increased the understanding of the physical requirements of the game, and using this knowledge, exercise programs aimed at improving golf performance have been developed. However, while it is generally accepted that an exercise program can improve a golfer's physical measurements and some golf performance variables, translating the findings from research into clinical practice to optimise an individual golfer's performance remains challenging. This paper discusses how biomechanical and motor control research has informed current practice and discusses how emerging sophisticated tools and research designs may better assist golfers improve their performance. PMID:26537808

Local infusion of ascorbate augments NO-dependent cutaneous vasodilatation during intense exercise in the heat

PubMed Central

Meade, Robert D; Fujii, Naoto; Alexander, Lacy M; Paull, Gabrielle; Louie, Jeffrey C; Flouris, Andreas D; Kenny, Glen P

2015-01-01

Abstract Nitric oxide (NO)-dependent cutaneous vasodilatation is reportedly diminished during exercise performed at a high (700 W) relative to moderate (400 W) rate of metabolic heat production. The present study evaluated whether this impairment results from increased oxidative stress associated with an accumuluation of reactive oxygen species (ROS) during high intensity exercise. On two separate days, 11 young (mean ± SD, 24 ± 4 years) males cycled in the heat (35°C) at a moderate (500 W) or high (700 W) rate of metabolic heat production. Each session included two 30 min exercise bouts followed by 20 and 40 min of recovery, respectively. Cutaneous vascular conductance (CVC) was monitored at four forearm skin sites continuously perfused via intradermal microdialysis with: (1) lactated Ringer solution (Control); (2) 10 mm ascorbate (Ascorbate); (3) 10 mm l-NAME; or (4) 10 mm ascorbate + 10 mm l-NAME (Ascorbate + l-NAME). At the end of each 500 W exercise bout, CVC was attenuated with l-NAME (∼35% CVCmax) and Ascorbate + l-NAME (∼43% CVCmax) compared to Control (∼60% CVCmax; all P < 0.04); however, Ascorbate did not modulate CVC during exercise (∼60% CVCmax; both P > 0.87). Conversely, CVC was elevated with Ascorbate (∼72% CVCmax; both P < 0.03) but remained similar to Control (∼59% CVCmax) with l-NAME (∼50% CVCmax) and Ascorbate + l-NAME (∼47% CVCmax; all P > 0.05) at the end of both 700 W exercise bouts. We conclude that oxidative stress associated with an accumulation of ascorbate-sensitive ROS impairs NO-dependent cutaneous vasodilatation during intense exercise. Key points Recent work demonstrates that nitric oxide (NO) contributes to cutaneous vasodilatation during moderate (400 W of metabolic heat production) but not high (700 W of metabolic heat production) intensity exercise bouts performed in the heat (35°C). The present study evaluated whether the impairment in NO-dependent cutaneous vasodilatation was the result of a greater accumulation of reactive oxygen species during high (700 W of metabolic heat production) relative to moderate (500 W of metabolic heat production) intensity exercise. It was shown that local infusion of ascorbate (an anti-oxidant) improves NO-dependent forearm cutaneous vasodilatation during high intensity exercise in the heat. These findings provide novel insight into the physiological mechanisms governing cutaneous blood flow during exercise-induced heat stress and provide direction for future research exploring whether oxidative stress underlies the impairments in heat dissipation that may occur in older adults, as well as in individuals with pathophysiological conditions such as type 2 diabetes. PMID:26110415

Lower-volume muscle-damaging exercise protects against high-volume muscle-damaging exercise and the detrimental effects on endurance performance.

PubMed

Burt, Dean; Lamb, Kevin; Nicholas, Ceri; Twist, Craig

2015-07-01

This study examined whether lower-volume exercise-induced muscle damage (EIMD) performed 2 weeks before high-volume muscle-damaging exercise protects against its detrimental effect on running performance. Sixteen male participants were randomly assigned to a lower-volume (five sets of ten squats, n = 8) or high-volume (ten sets of ten squats, n = 8) EIMD group and completed baseline measurements for muscle soreness, knee extensor torque, creatine kinase (CK), a 5-min fixed-intensity running bout and a 3-km running time-trial. Measurements were repeated 24 and 48 h after EIMD, and the running time-trial after 48 h. Two weeks later, both groups repeated the baseline measurements, ten sets of ten squats and the same follow-up testing (Bout 2). Data analysis revealed increases in muscle soreness and CK and decreases in knee extensor torque 24-48 h after the initial bouts of EIMD. Increases in oxygen uptake [Formula: see text], minute ventilation [Formula: see text] and rating of perceived exertion were observed during fixed-intensity running 24-48 h after EIMD Bout 1. Likewise, time increased and speed and [Formula: see text] decreased during a 3-km running time-trial 48 h after EIMD. Symptoms of EIMD, responses during fixed-intensity and running time-trial were attenuated in the days after the repeated bout of high-volume EIMD performed 2 weeks after the initial bout. This study demonstrates that the protective effect of lower-volume EIMD on subsequent high-volume EIMD is transferable to endurance running. Furthermore, time-trial performance was found to be preserved after a repeated bout of EIMD.

The Elite Athlete and Strenuous Exercise in Pregnancy.

PubMed

Pivarnik, James M; Szymanski, Linda M; Conway, Michelle R

2016-09-01

Highly trained women continue to exercise during pregnancy, but there is little information available to guide them, and their health care providers, in how to maximize performance without jeopardizing the maternal-fetal unit. Available evidence focusing on average women who perform regular vigorous exercise suggests that this activity is helpful in preventing several maladies of pregnancy, with little to no evidence of harm. However, some studies have shown that there may be a limit to how intense an elite performer should exercise during pregnancy. Health care providers should monitor these women athletes carefully, to build trust and understanding.

Effect of high wavelengths low intensity light during dark period on physical exercise performance, biochemical and haematological parameters of swimming rats.

PubMed

Beck, W; Gobatto, C

2016-03-01

Nocturnal rodents should be assessed at an appropriate time of day, which leads to a challenge in identifying an adequate environmental light which allows animal visualisation without perturbing physiological homeostasis. Thus, we analysed the influence of high wavelength and low intensity light during dark period on physical exercise and biochemical and haematological parameters of nocturnal rats. We submitted 80 animals to an exhaustive exercise at individualised intensity under two different illuminations during dark period. Red light (> 600 nm; < 15lux) was applied constantly during dark period (EI; for experimental illumination groups) or only for handling and assessments (SI; for standard illumination groups). EI led to worse haematological and biochemical conditions, demonstrating that EI alone can influence physiological parameters and jeopardise result interpretation. SI promotes normal physiological conditions and greater aerobic tolerance than EI, showing the importance of a correct illumination pattern for all researchers that employ nocturnal rats for health/disease or sports performance experiments.

A Carbohydrate Ingestion Intervention in an Elite Athlete Who Follows a LCHF Diet.

PubMed

Webster, Christopher C; Swart, Jeroen; Noakes, Timothy D; Smith, James A

2017-12-18

This case study documents the performance of an elite-level, exceptionally well fat-adapted endurance athlete, as he reintroduced carbohydrate ingestion during high-intensity training. He had followed a strict low-carbohydrate high-fat (LCHF) diet for 2 years during which he ate approximately 80 g of carbohydrate per day and trained and raced while ingesting only water. While following this diet, he earned numerous podium finishes in triathlons of various distances. However, he approached us to test whether carbohydrate supplementation during exercise would further increase his high-intensity performance without affecting his fat-adaptation. This 7-week n=1 investigation included a 4-week habitual LCHF diet phase (LCHF) during which he drank only water during training and performance trials, and a 3-week habitual diet plus carbohydrate ingestion phase (LCHF+CHO), during which he followed his usual LCHF diet but ingested 60 g/h carbohydrate during 8 high-intensity training sessions and performance trials. After each phase, rates of fat oxidation and 30 s sprint, 4 min sprint, 20 km time trial (TT), and 100 km TT performances were measured. Compared to LCHF, 20 km TT time improved by 2.8 % after LCHF+CHO, which would be a large difference in competition. There was no change in 30 s sprint power; a small improvement in 4 min sprint power (1.6 %); and a small reduction in 100 km TT time (1.1%). We conclude that carbohydrate ingestion during exercise was likely beneficial for this fat-adapted athlete during high-intensity endurance-type exercise (4-30 min) but likely did not benefit his short sprint or prolonged endurance performance.

The effects of a high-intensity free-weight back-squat exercise protocol on postural stability in resistance-trained males.

PubMed

Thiele, R M; Conchola, E C; Palmer, T B; DeFreitas, J M; Thompson, B J

2015-01-01

The purpose of this study was to investigate the effects of a high-intensity free-weight back-squat exercise on postural stability characteristics in resistance-trained males. Eighteen college-aged (mean ± SD: age = 22.9 ± 2.9 years; height = 175.8 ± 6.4 cm; mass = 86.3 ± 9.3 kg), resistance-trained males performed postural stability testing before and after completing five sets of eight repetitions of back-squat exercises at 80% of one-repetition maximum. A commercial balance testing device was used to assess sway index at pre- and at 0, 5, 10, 15 and 20 min post-exercise. Each balance assessment consisted of four, 20-s static stance conditions: eyes-open firm surface, eyes-closed firm surface, eyes-open soft surface and eyes-closed soft surface. Sway index was greater (P = 0.001-0.020) at Post 0 than at all other time points. No differences (P > 0.05) were observed between any other time phases. Sway index was greater (P < 0.001) for eyes-closed soft surface than all other conditions. These findings revealed sway index for all conditions significantly increased following completion of the back-squat; however, sway index recovered within 5 min of exercise. Higher sway index values as a result of neuromuscular fatigue induced by a back-squat exercise may have performance and injury risk consequences to subsequent activities that rely on postural stability. However, these findings suggest balance impairments may recover in ~5 min following high-intensity lower body resistance exercise.

Carbohydrate Dependence During Prolonged, Intense Endurance Exercise.

PubMed

Hawley, John A; Leckey, Jill J

2015-11-01

A major goal of training to improve the performance of prolonged, continuous, endurance events lasting up to 3 h is to promote a range of physiological and metabolic adaptations that permit an athlete to work at both higher absolute and relative power outputs/speeds and delay the onset of fatigue (i.e., a decline in exercise intensity). To meet these goals, competitive endurance athletes undertake a prodigious volume of training, with a large proportion performed at intensities that are close to or faster than race pace and highly dependent on carbohydrate (CHO)-based fuels to sustain rates of muscle energy production [i.e., match rates of adenosine triphosphate (ATP) hydrolysis with rates of resynthesis]. Consequently, to sustain muscle energy reserves and meet the daily demands of training sessions, competitive athletes freely select CHO-rich diets. Despite renewed interest in high-fat, low-CHO diets for endurance sport, fat-rich diets do not improve training capacity or performance, but directly impair rates of muscle glycogenolysis and energy flux, limiting high-intensity ATP production. When highly trained athletes compete in endurance events lasting up to 3 h, CHO-, not fat-based fuels are the predominant fuel for the working muscles and CHO, not fat, availability becomes rate limiting for performance.

Alterations in Aerobic Exercise Performance and Gait Economy Following High-Intensity Dynamic Stepping Training in Persons With Subacute Stroke.

PubMed

Leddy, Abigail L; Connolly, Mark; Holleran, Carey L; Hennessy, Patrick W; Woodward, Jane; Arena, Ross A; Roth, Elliot J; Hornby, T George

2016-10-01

Impairments in metabolic capacity and economy (O2cost) are hallmark characteristics of locomotor dysfunction following stroke. High-intensity (aerobic) training has been shown to improve peak oxygen consumption in this population, with fewer reports of changes in O2cost. However, particularly in persons with subacute stroke, inconsistent gains in walking function are observed with minimal associations with gains in metabolic parameters. The purpose of this study was to evaluate changes in aerobic exercise performance in participants with subacute stroke following high-intensity variable stepping training as compared with conventional therapy. A secondary analysis was performed on data from a randomized controlled trial comparing high-intensity training with conventional interventions, and from the pilot study that formed the basis for the randomized controlled trial. Participants 1 to 6 months poststroke received 40 or fewer sessions of high-intensity variable stepping training (n = 21) or conventional interventions (n = 12). Assessments were performed at baseline (BSL), posttraining, and 2- to 3-month follow-up and included changes in submaximal (Equation is included in full-text article.)O2 ((Equation is included in full-text article.)O2submax) and O2cost at fastest possible treadmill speeds and peak speeds at BSL testing. Significant improvements were observed in (Equation is included in full-text article.)O2submax with less consistent improvements in O2cost, although individual responses varied substantially. Combined changes in both (Equation is included in full-text article.)O2submax and (Equation is included in full-text article.)O2 at matched peak BSL speeds revealed stronger correlations to improvements in walking function as compared with either measure alone. High-intensity stepping training may elicit significant improvements in (Equation is included in full-text article.)O2submax, whereas changes in both peak capacity and economy better reflect gains in walking function. Providing high-intensity training to improve locomotor and aerobic exercise performance may increase the efficiency of rehabilitation sessions.Video Abstract available for more insights from the authors (see Supplemental Digital Content, http://links.lww.com/JNPT/A142).

New perspectives concerning feedback influences on cardiorespiratory control during rhythmic exercise and on exercise performance

PubMed Central

Dempsey, Jerome A

2012-01-01

The cardioaccelerator and ventilatory responses to rhythmic exercise in the human are commonly viewed as being mediated predominantly via feedforward ‘central command’ mechanisms, with contributions from locomotor muscle afferents to the sympathetically mediated pressor response. We have assessed the relative contributions of three types of feedback afferents on the cardiorespiratory response to voluntary, rhythmic exercise by inhibiting their normal ‘tonic’ activity in healthy animals and humans and in chronic heart failure. Transient inhibition of the carotid chemoreceptors during moderate intensity exercise reduced muscle sympathetic nerve activity (MSNA) and increased limb vascular conductance and blood flow; and reducing the normal level of respiratory muscle work during heavier intensity exercise increased limb vascular conductance and blood flow. These cardiorespiratory effects were prevented via ganglionic blockade and were enhanced in chronic heart failure and in hypoxia. Blockade of μ opioid sensitive locomotor muscle afferents, with preservation of central motor output via intrathecal fentanyl: (a) reduced the mean arterial blood pressure (MAP), heart rate and ventilatory responses to all steady state exercise intensities; and (b) during sustained high intensity exercise, reduced O2 transport, increased central motor output and end-exercise muscle fatigue and reduced endurance performance. We propose that these three afferent reflexes – probably acting in concert with feedforward central command – contribute significantly to preserving O2 transport to locomotor and to respiratory muscles during exercise. Locomotor muscle afferents also appear to provide feedback concerning the metabolic state of the muscle to influence central motor output, thereby limiting peripheral fatigue development. PMID:22826128

Practical Approaches to Prescribing Physical Activity and Monitoring Exercise Intensity.

PubMed

Reed, Jennifer L; Pipe, Andrew L

2016-04-01

Regular physical activity helps to prevent heart disease, and reduces the risk of first or subsequent cardiovascular events. It is recommended that Canadian adults accumulate at least 150 minutes of moderate- to vigorous-intensity aerobic exercise per week, in bouts of 10 minutes or more, and perform muscle- and bone-strengthening activities at least 2 days per week. Individual exercise prescriptions can be developed using the frequency, intensity, time, and type principles. Increasing evidence suggests that high-intensity interval training is efficacious for a broad spectrum of heart health outcomes. Several practical approaches to prescribing and monitoring exercise intensity exist including: heart rate monitoring, the Borg rating of perceived exertion scale, the Talk Test, and, motion sensors. The Borg rating of perceived exertion scale matches a numerical value to an individual's perception of effort, and can also be used to estimate heart rate. The Talk Test, the level at which simple conversation is possible, can be used to monitor desired levels of moderate- to vigorous-intensity exercise. Motion sensors can provide users with practical and useful exercise training information to aid in meeting current exercise recommendations. These approaches can be used by the public, exercise scientists, and clinicians to easily and effectively guide physical activity in a variety of settings. Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

PGC-1α and exercise intensity dependent adaptations in mouse skeletal muscle

PubMed Central

Dethlefsen, Maja Munk; Bangsbo, Jens; Pilegaard, Henriette

2017-01-01

The aim of the present study was to examine the role of PGC-1α in intensity dependent exercise and exercise training-induced metabolic adaptations in mouse skeletal muscle. Whole body PGC-1α knockout (KO) and littermate wildtype (WT) mice performed a single treadmill running bout at either low intensity (LI) for 40 min or moderate intensity (MI) for 20 min. Blood and quadriceps muscles were removed either immediately after exercise or at 3h or 6h into recovery from exercise and from resting controls. In addition PGC-1α KO and littermate WT mice were exercise trained at either low intensity (LIT) for 40 min or at moderate intensity (MIT) for 20 min 2 times pr. day for 5 weeks. In the first and the last week of the intervention period, mice performed a graded running endurance test. Quadriceps muscles were removed before and after the training period for analyses. The acute exercise bout elicited intensity dependent increases in LC3I and LC3II protein and intensity independent decrease in p62 protein in skeletal muscle late in recovery and increased LC3II with exercise training independent of exercise intensity and volume in WT mice. Furthermore, acute exercise and exercise training did not increase LC3I and LC3II protein in PGC-1α KO. In addition, exercise-induced mRNA responses of PGC-1α isoforms were intensity dependent. In conclusion, these findings indicate that exercise intensity affected autophagy markers differently in skeletal muscle and suggest that PGC-1α regulates both acute and exercise training-induced autophagy in skeletal muscle potentially in a PGC-1α isoform specific manner. PMID:29049322

Benefits of supplemental oxygen in exercise training in nonhypoxemic chronic obstructive pulmonary disease patients.

PubMed

Emtner, Margareta; Porszasz, Janos; Burns, Mary; Somfay, Attila; Casaburi, Richard

2003-11-01

Supplemental oxygen improves exercise tolerance of normoxemic and hypoxemic chronic obstructive pulmonary disease (COPD) patients. We determined whether nonhypoxemic COPD patients undergoing exercise training while breathing supplemental oxygen achieve higher intensity and therefore improve exercise capacity more than patients breathing air. A double-blinded trial was performed involving 29 nonhypoxemic patients (67 years, exercise SaO2 > 88%) with COPD (FEV1 = 36% predicted). All exercised on cycle ergometers for 45 minutes, 3 times per week for 7 weeks at high-intensity targets. During exercise, they received oxygen (3 L/minute) (n = 14) or compressed air (3 L/minute) (n = 15). Both groups had a higher exercise tolerance after training and when breathing oxygen. However, the oxygen-trained group increased the training work rate more rapidly than the air-trained group. The mean +/- SD work rate during the last week was 62 +/- 19 W (oxygen-trained group) and 52 +/- 22 W (air-trained group) (p < 0.01). After training, endurance in constant work rate tests increased more in the oxygen-trained group (14.5 minutes) than in the air-trained group (10.5 minutes) (p < 0.05). At isotime, the breathing rate decreased four breaths per minute in the oxygen-trained group and one breath per minute in the air-trained group (p = 0.001). We conclude that supplemental oxygen provided during high-intensity training yields higher training intensity and evidence of gains in exercise tolerance in laboratory testing.

Decline in Executive Control during Acute Bouts of Exercise as a Function of Exercise Intensity and Fitness Level

ERIC Educational Resources Information Center

Labelle, Veronique; Bosquet, Laurent; Mekary, Said; Bherer, Louis

2013-01-01

Studies on the effects of acute bouts of cardiovascular exercise on cognitive performances show contradictory findings due to methodological differences (e.g., exercise intensity, cognitive function assessed, participants' aerobic fitness level, etc.). The present study assessed the acute effect of exercise intensity on cognition while controlling…

Incorporating yoga into an intense physical therapy program in someone with Parkinson's disease: a case report.

PubMed

Moriello, Gabriele; Denio, Christopher; Abraham, Megan; DeFrancesco, Danielle; Townsley, Jill

2013-10-01

The purpose of this case report was to document outcomes following an intense exercise program integrating yoga with physical therapy exercise in a male with Parkinson's disease. The participant performed an intense 1½-hour program (Phase A) incorporating strengthening, balance, agility and yoga exercises twice weekly for 12 weeks. He then completed a new home exercise program developed by the researchers (Phase B) for 12 weeks. His score on the Parkinson's Disease Questionnaire improved 16 points while his score on the High Level Mobility Assessment tool improved 11 points. There were also improvements in muscle length of several lower extremity muscles, in upper and lower extremity muscle strength, in dynamic balance and he continues to work full time 29 months later. There were no improvements in thoracic posture or aerobic power. This intense program was an effective dose of exercise for someone with Parkinson's disease and allowed him to continue to participate in work, leisure, and community activities. Copyright © 2013 Elsevier Ltd. All rights reserved.

Short-term high-intensity interval exercise training attenuates oxidative stress responses and improves antioxidant status in healthy humans.

PubMed

Bogdanis, G C; Stavrinou, P; Fatouros, I G; Philippou, A; Chatzinikolaou, A; Draganidis, D; Ermidis, G; Maridaki, M

2013-11-01

This study investigated the changes in oxidative stress biomarkers and antioxidant status indices caused by a 3-week high-intensity interval training (HIT) regimen. Eight physically active males performed three HIT sessions/week over 3 weeks. Each session included four to six 30-s bouts of high-intensity cycling separated by 4 min of recovery. Before training, acute exercise elevated protein carbonyls (PC), thiobarbituric acid reactive substances (TBARS), glutathione peroxidase (GPX) activity, total antioxidant capacity (TAC) and creatine kinase (CK), which peaked 24h post-exercise (252 ± 30%, 135 ± 17%, 10 ± 2%, 85 ± 14% and 36 ± 13%, above baseline, respectively; p<0.01), while catalase activity (CAT) peaked 30 min post-exercise (56 ± 18% above baseline; p<0.01). Training attenuated the exercise-induced increase in oxidative stress markers (PC by 13.3 ± 3.7%; TBARS by 7.2 ± 2.7%, p<0.01) and CK activity, despite the fact that total work done was 10.9 ± 3.6% greater in the post- compared with the pre-training exercise test. Training also induced a marked elevation of antioxidant status indices (TAC by 38.4 ± 7.2%; CAT by 26.2 ± 10.1%; GPX by 3.0 ± 0.6%, p<0.01). Short-term HIT attenuates oxidative stress and up-regulates antioxidant activity after only nine training sessions totaling 22 min of high intensity exercise, further supporting its positive effect not only on physical conditioning but also on health promotion. Copyright © 2013 Elsevier Ltd. All rights reserved.

Circulating adiponectin concentration and body composition are altered in response to high-intensity interval training.

PubMed

Shing, Cecilia M; Webb, Jessica J; Driller, Matthew W; Williams, Andrew D; Fell, James W

2013-08-01

Adiponectin influences metabolic adaptations that would prove beneficial to endurance athletes, and yet to date there is little known about the response of adiponectin concentrations to exercise, and, in particular, the response of this hormone to training in an athlete population. This study aimed to determine the response of plasma adiponectin concentrations to acute exercise after 2 different training programs and to determine the influence of the training on body composition. Seven state-level representative rowers (age: 19 ± 1.2 years [mean ± SD], height: 1.77 ± 0.10 m, body mass: 74.0 ± 10.7 kg, VO2peak 62.1 ± 7.0 ml·kg·min) participated in the double-blind, randomized crossover investigation. Rowers performed an incremental graded exercise test before and after completing 4 weeks of high-intensity interval ergometer training and 4 weeks of traditional ergometer rowing training. Rowers' body composition was assessed at baseline and after each training program. Significant increases in plasma adiponectin concentration occurred in response to maximal exercise after completion of the high-intensity interval training (p = 0.016) but not after traditional ergometer rowing training (p = 0.69). The high-intensity interval training also resulted in significant increases in mean 4-minute power output (p = 0.002) and VO2peak (p = 0.05), and a decrease in body fat percentage (p = 0.022). Mean 4-minute power output, VO2peak, and body fat percentage were not significantly different after 4 weeks of traditional ergometer rowing training (p > 0.05). Four weeks of high-intensity interval training is associated with an increase in adiponectin concentration in response to maximal exercise and a reduction in body fat percentage. The potential for changes in adiponectin concentration to reflect positive training adaptations and athlete performance level should be further explored.

Preferred Exertion across Three Common Modes of Exercise Training.

ERIC Educational Resources Information Center

Glass, Stephen C.; Chvala, Angela M.

2001-01-01

Examined the influence of exercise mode on self-selected exercise intensities. Participants performed three types of intensity tests. Researchers collected data on VO2 values continuously and recorded 1-minute averages several times for each submaximal test. Participants allowed to self-select exercise intensity chose work rates within the…

Comparison of Psychological and Physiological Responses to Imposed vs. Self-selected High-Intensity Interval Training.

PubMed

Kellogg, Erin; Cantacessi, Cheyann; McNamer, Olivia; Holmes, Heather; von Bargen, Robert; Ramirez, Richard; Gallagher, Daren; Vargas, Stacy; Santia, Ben; Rodriguez, Karen; Astorino, Todd A

2018-05-08

Kellogg, E, Cantacessi, C, McNamer, O, Holmes, H, von Bargen, R, Ramirez, R, Gallagher, D, Vargas, S, Santia, B, Rodriguez, K, and Astorino, TA. Comparison of psychological and physiological responses to imposed vs. self-selected high-intensity interval training. J Strength Cond Res XX(X): 000-000, 2018-High-intensity interval training elicits similar physiological adaptations as moderate intensity continuous training (MICT). Some studies report greater enjoyment to a bout of high-intensity interval exercise (HIIE) vs. MICT, which is surprising considering that HIIE is more intense and typically imposed on the participant. This study compared physiological and perceptual responses between imposed and self-selected HIIE. Fourteen adults (age = 24 ± 3 years) unfamiliar with HIIE initially performed ramp exercise to exhaustion to measure maximal oxygen uptake (V[Combining Dot Above]O2max) followed by 2 subsequent sessions whose order was randomized. Imposed HIIE consisted of eight 60 seconds bouts at 80 percent peak power output (%PPO) separated by 60 seconds recovery at 10 %PPO. Self-selected HIIE (HIIESS) followed the same structure, but participants freely selected intensity in increments of 10 %PPO to achieve a rating of perceived exertion (RPE) ≥7. During exercise, heart rate, V[Combining Dot Above]O2, blood lactate concentration (BLa), affect (+5 to -5), and RPE were assessed. Physical Activity Enjoyment Scale was measured after exercise. Results showed higher V[Combining Dot Above]O2 (+10%, p = 0.013), BLa (p = 0.001), and RPE (p = 0.001) in HIIESS vs. HIIEIMP, and lower affect (p = 0.01), and enjoyment (87.6 ± 15.7 vs. 95.7 ± 11.7, p = 0.04). There was a significantly higher power output in self-selected vs. imposed HIIE (263.9 ± 81.4 W vs. 225.2 ± 59.6 W, p < 0.001). Data suggest that intensity mediates affective responses rather than the mode of HIIE performed by the participant.

Acute high-intensity endurance exercise is more effective than moderate-intensity exercise for attenuation of postprandial triglyceride elevation.

PubMed

Trombold, Justin R; Christmas, Kevin M; Machin, Daniel R; Kim, Il-Young; Coyle, Edward F

2013-03-15

Acute exercise has been shown to attenuate postprandial plasma triglyceride elevation (PPTG). However, the direct contribution of exercise intensity is less well understood. The purpose of this study was to examine the effects of exercise intensity on PPTG and postprandial fat oxidation. One of three experimental treatments was performed in healthy young men (n = 6): nonexercise control (CON), moderate-intensity exercise (MIE; 50% Vo2peak for 60 min), or isoenergetic high-intensity exercise (HIE; alternating 2 min at 25% and 2 min at 90% Vo2peak). The morning after the exercise, a standardized meal was provided (16 kcal/kg BM, 1.02 g fat/kg, 1.36 g CHO/kg, 0.31 g PRO/kg), and measurements of plasma concentrations of triglyceride (TG), glucose, insulin, and β-hydroxybutyrate were made in the fasted condition and hourly for 6 h postprandial. Indirect calorimetry was used to determine fat oxidation in the fasted condition and 2, 4, and 6 h postprandial. Compared with CON, both MIE and HIE significantly attenuated PPTG [incremental AUC; 75.2 (15.5%), P = 0.033, and 54.9 (13.5%), P = 0.001], with HIE also significantly lower than MIE (P = 0.03). Postprandial fat oxidation was significantly higher in MIE [83.3 (10.6%) of total energy expenditure] and HIE [89.1 (9.8) %total] compared with CON [69.0 (16.1) %total, P = 0.039, and P = 0.018, respectively], with HIE significantly greater than MIE (P = 0.012). We conclude that, despite similar energy expenditure, HIE was more effective than MIE for lowering PPTG and increasing postprandial fat oxidation.

Ketone Bodies and Exercise Performance: The Next Magic Bullet or Merely Hype?

PubMed

Pinckaers, Philippe J M; Churchward-Venne, Tyler A; Bailey, David; van Loon, Luc J C

2017-03-01

Elite athletes and coaches are in a constant search for training methods and nutritional strategies to support training and recovery efforts that may ultimately maximize athletes' performance. Recently, there has been a re-emerging interest in the role of ketone bodies in exercise metabolism, with considerable media speculation about ketone body supplements being routinely used by professional cyclists. Ketone bodies can serve as an important energy substrate under certain conditions, such as starvation, and can modulate carbohydrate and lipid metabolism. Dietary strategies to increase endogenous ketone body availability (i.e., a ketogenic diet) require a diet high in lipids and low in carbohydrates for ~4 days to induce nutritional ketosis. However, a high fat, low carbohydrate ketogenic diet may impair exercise performance via reducing the capacity to utilize carbohydrate, which forms a key fuel source for skeletal muscle during intense endurance-type exercise. Recently, ketone body supplements (ketone salts and esters) have emerged and may be used to rapidly increase ketone body availability, without the need to first adapt to a ketogenic diet. However, the extent to which ketone bodies regulate skeletal muscle bioenergetics and substrate metabolism during prolonged endurance-type exercise of varying intensity and duration remains unknown. Therefore, at present there are no data available to suggest that ingestion of ketone bodies during exercise improves athletes' performance under conditions where evidence-based nutritional strategies are applied appropriately.

Intensive Exercise Training During Bed Rest Attenuates Deconditioning

NASA Technical Reports Server (NTRS)

Greenleaf, John E.

1997-01-01

Intensive exercise training during bed rest attenuates deconditioning. Med. Sci. Sports Exerc., Vol. 29, No. 2, pp. 207-215, 1997. A 30-d 6 deg head-down bed rest project was conducted to evaluate variable high-intensity, short-duration, isotonic cycle ergometer exercise (ITE) training and high-intensity intermittent resistive isokinetic exercise (IKE) training regimens designed to maintain peak VO2 and muscle mass, strength, and endurance at ambulatory control levels throughout prolonged bed rest. Other elements of the deconditioning (adaptive) syndrome, such as proprioception, psychological performance, hypovolemia, water balance, body composition, and orthostatic tolerance, were also measured. Major findings are summarized in this paper. Compared with response during bed rest of the no exercise (NOE) control group: the ITE training regimen (a) maintained work capacity (peak VO2), (b) maintained plasma and red cell volumes, (c) induced positive body water balance, (d) decreased quality of sleep and mental concentration, and (e) had no effect on the decrease in orthostatic tolerance; the IKE training regimen (f) attenuated the decrease in peak VO2 by 50%, (g) attenuated loss of red cell volume by 40% but had no effect on loss of plasma volume, (b) induced positive body water balance, (i) had no adverse effect on quality of sleep or concentration, and 0) had no effect on the decrease in orthostatic tolerance. These findings suggest that various elements of the deconditioning syndrome can be manipulated by duration and intensity of ITE or IKE training regimens and that several different training protocols will be required to maintain or restore physiological and psychological performance of individuals confined to prolonged bed rest.

Continence and quality-of-life outcomes 6 months following an intensive pelvic-floor muscle exercise program for female stress urinary incontinence: a randomized trial comparing low- and high-frequency maintenance exercise.

PubMed

Borello-France, Diane F; Downey, Patricia A; Zyczynski, Halina M; Rause, Christine R

2008-12-01

Few studies have examined the effectiveness of pelvic-floor muscle (PFM) exercises to reduce female stress urinary incontinence (SUI) over the long term. This study: (1) evaluated continence and quality-of-life outcomes of women 6 months following formalized therapy and (2) determined whether low- and high-frequency maintenance exercise programs were equivalent in sustaining outcomes. Thirty-six women with SUI who completed an intensive PFM exercise intervention trial were randomly assigned to perform a maintenance exercise program either 1 or 4 times per week. Urine leaks per week, volume of urine loss, quality of life (Incontinence Impact Questionnaire [IIQ] score), PFM strength (Brink score), and prevalence of urodynamic stress incontinence (USI) were measured at a 6-month follow-up for comparison with postintervention status. Parametric and nonparametric statistics were used to determine differences in outcome status over time and between exercise frequency groups. Twenty-eight women provided follow-up data. Postintervention status was sustained at 6 months for all outcomes (mean [SD] urine leaks per week=1.2+/-2.1 versus 1.4+/-3.1; mean [SD] urine loss=0.2+/-0.5 g versus 0.2+/-0.8 g; mean [SD] IIQ score=17+/-20 versus 22+/-30; mean [SD] Brink score=11+/-1 versus 11+/-1; and prevalence of USI=48% versus 35%). Women assigned to perform exercises once or 4 times per week similarly sustained their postintervention status. Benefits of an initial intensive intervention program for SUI were sustained over 6 months. However, only 15 of the 28 women provided documentation of their exercise adherence, limiting conclusions regarding the need for continued PFM exercise during follow-up intervals of

Changes in blood glucose among trained normoglycemic adults during a mini-trampoline exercise session.

PubMed

Martins Cunha, Raphael; Raiana Bentes, Mariana; Araújo, Victor H; DA Costa Souza, Mayara C; Vasconcelos Noleto, Marcelo; Azevedo Soares, Ademar; Machado Lehnen, Alexandre

2016-12-01

Blood glucose changes response during and after exercise are modulated by the postabsorptive state, intensity and duration of exercise, and the level of physical fitness as well. This study focused on the idea that high-intensity interval exercise, as mini-trampoline class, can reduce blood glucose. Thus, we examined acute changes in blood glucose among trained normoglycemic adults during a mini-trampoline exercise session. Twenty-four normoglycemic adult subjects were enrolled in the study. After physical assessment they were randomly assigned to either the experimental (N.=12) or the control group (N.=12). The experimental group performed a 50-minute session of moderate-to-high intensity (70 to 85% HRmax) exercise on a mini-trampoline commonly used in fitness classes. The control group did not perform any exercise, and all procedures were otherwise similar to the experimental group. Capillary blood glucose was measured before and every 15 minutes during the exercise session. The effects of exercise on blood glucose levels (group; time; and group interaction) were estimated using a generalized estimating equation (GEE) followed by Bonferroni's post-hoc Test (P<0.05). The experimental group showed a decrease in blood glucose levels from baseline (108.7 mg/dL): 26.1% reduction (15 min; P<0.001), 24.2% (30 min; P<0.001), and 15.7% (45 min; P<0.001). Compared to the control group, blood glucose levels in the experimental group were reduced by 18.8% (15 min; P<0.001), 14.3% (30 min; P<0.001) and 6.9% (45 min; P=0.025). The study results provide good evidence that a prescribed exercise program on a mini-trampoline can be used for reducing blood glucose levels and thus can potentially control blood glucose.

An isoenergetic high-protein, moderate-fat diet does not compromise strength and fatigue during resistance exercise in women.

PubMed

Dipla, Konstantina; Makri, Maria; Zafeiridis, Andreas; Soulas, Dimitrios; Tsalouhidou, Sofia; Mougios, Vassilis; Kellis, Spyros

2008-08-01

Resistance exercise is recommended to individuals following high-protein diets in order to augment changes in body composition. However, alterations in macronutrient composition may compromise physical performance. The present study investigated the effects of an isoenergetic high-protein diet on upper and lower limb strength and fatigue during high-intensity resistance exercise. Ten recreationally active women, aged 25-40 years, followed a control diet (55, 15 and 30 % of energy from carbohydrate, protein and fat, respectively) and a high-protein diet (respective values, 30, 40 and 30) for 7 d each in a random counterbalanced design. Each participant underwent strength testing of upper limb (isometric handgrip strength and endurance) and lower limb (four sets of sixteen maximal knee flexions and extensions on an isokinetic dynamometer) before and after applying each diet. Body weight, body fat and RER were significantly reduced following the high-protein diet (P < 0.05). No differences were found between diets in any of the strength performance parameters (handgrip strength, handgrip endurance, peak torque, total work and fatigue) or the responses of heart rate, systolic and diastolic arterial pressure, blood lactate and blood glucose to exercise. Women on a short-term isoenergetic high-protein, moderate-fat diet maintained muscular strength and endurance of upper and lower limbs during high-intensity resistance exercise without experiencing fatigue earlier compared with a control diet.

Changes in transverse relaxation time of quadriceps femoris muscles after active recovery exercises with different intensities.

PubMed

Mukaimoto, Takahiro; Semba, Syun; Inoue, Yosuke; Ohno, Makoto

2014-01-01

The purpose of this study was to examine the changes in the metabolic state of quadriceps femoris muscles using transverse relaxation time (T2), measured by muscle functional magnetic resonance (MR) imaging, after inactive or active recovery exercises with different intensities following high-intensity knee-extension exercise. Eight healthy men performed recovery sessions with four different conditions for 20 min after high-intensity knee-extension exercise on separate days. During the recovery session, the participants conducted a light cycle exercise for 20 min using a cycle (50%, 70% and 100% of the lactate threshold (LT), respectively: active recovery), and inactive recovery. The MR images of quadriceps femoris muscles were taken before the trial and after the recovery session every 30 min for 120 min. The percentage changes in T2 for the rectus femoris and vastus medialis muscles after the recovery session in 50% LT and 70% LT were significantly lower than those in either inactive recovery or 100% LT. There were no significant differences in those for vastus lateralis and vastus intermedius muscles among the four trials. The percentage changes in T2 of rectus femoris and vastus medialis muscles after the recovery session in 50% LT and 70% LT decreased to the values before the trial faster than those in either inactive recovery or 100% LT. Those of vastus lateralis and vastus intermedius muscles after the recovery session in 50% LT and 70% LT decreased to the values before the trial faster than those in 100% LT. Although the changes in T2 after active recovery exercises were not uniform in exercised muscles, the results of this study suggest that active recovery exercise with the intensities below LT are more effective to recover the metabolic state of quadriceps femoris muscles after intense exercise than with either intensity at LT or inactive recovery.

Self-selected music-induced reduction of perceived exertion during moderate-intensity exercise does not interfere with post-exercise improvements in inhibitory control.

PubMed

Tanaka, Daichi; Tsukamoto, Hayato; Suga, Tadashi; Takenaka, Saki; Hamaoka, Takafumi; Hashimoto, Takeshi; Isaka, Tadao

2018-05-26

Acute aerobic exercise improves inhibitory control (IC). This improvement is often associated with increases in perceived exertion during exercise. However, listening to music during aerobic exercise mitigates an exercise-induced increase in perceived exertion. Thus, it is hypothesized that such effects of music may interfere with exercise-induced improvements in IC. To test this hypothesis, we examined the effect of music on post-exercise IC improvements that were induced by moderate-intensity exercise. Fifteen healthy young men performed cycle ergometer exercise with music or non-music. The exercise was performed using a moderate-intensity of 60% of VO 2 peak for 30 min. The music condition was performed while listening to self-selected music. The non-music condition involved no music. To evaluate IC, the Stroop task was administered before exercise, immediately after exercise, and during the 30-min post-exercise recovery period. The rate of perceived exertion immediately before moderate-intensity exercise completed was significantly lower in music condition than in non-music condition. The IC significantly improved immediately after exercise and during the post-exercise recovery period compared to before exercise in both music and non-music conditions. The post-exercise IC improvements did not significantly differ between the two conditions. These findings indicate that self-selected music-induced mitigation of the increase in perceived exertion during moderate-intensity exercise dose not interfere with exercise-induced improvements in IC. Therefore, we suggest that listening to music may be a beneficial strategy in mitigating the increase in perceived exertion during aerobic exercise without decreasing the positive effects on IC. Copyright © 2018 Elsevier Inc. All rights reserved.

NASA's Functional Task Test: High Intensity Exercise Improves the Heart Rate Response to a Stand Test Following 70 Days of Bedrest

NASA Technical Reports Server (NTRS)

Laurie, Steven S.; Lee, Stuart M. C.; Phillips, Tiffany R.; Dillon, E. Lichar; Sheffield-Moore, Melinda; Urban, Randall J.; Ploutz-Snyder, Lori; Stenger, Michael B.; Bloomberg, Jacob J.

2015-01-01

Cardiovascular adaptations due to spaceflight are modeled with 6deg head-down tilt bed rest (BR) and result in decreased orthostatic tolerance. We investigated if high-intensity resistive and aerobic exercise with and without testosterone supplementation would improve the heart rate (HR) response to a 3.5-min stand test and how quickly these changes recovered following BR. During 70 days of BR male subjects performed no exercise (Control, n=10), high intensity supine resistive and aerobic exercise (Exercise, n=9), or supine exercise plus supplemental testosterone (Exercise+T, n=8; 100 mg i.m., weekly in 2-week on/off cycles). We measured HR for 2 min while subjects were prone and for 3 min after standing twice before and 0, 1, 6, and 11 days after BR. Mixed-effects linear regression models were used to evaluate group, time, and interaction effects. Compared to pre-bed rest, prone HR was elevated on BR+0 and BR+1 in Control, but not Exercise or Exercise+T groups, and standing HR was greater in all 3 groups. The increase in prone and standing HR in Control subjects was greater than either Exercise or Exercise+T groups and all groups recovered by BR+6. The change in HR from prone to standing more than doubled on BR+0 in all groups, but was significantly less in the Exericse+T group compared to the Control, but not Exercise group. Exercise reduces, but does not prevent the increase in HR observed in response to standing. The significantly lower HR response in the Exercise+T group requires further investigation to determine physiologic significance.

Influence of Ramadan Fasting on Anaerobic Performance and Recovery Following Short time High Intensity Exercise.

PubMed

Karli, Umid; Guvenc, Alpay; Aslan, Alper; Hazir, Tahir; Acikada, Caner

2007-01-01

The aim of this study was to investigate the effects of Ramadan fasting on anaerobic power and capacity and the removal rate of lactate after short time high intensity exercise in power athletes. Ten male elite power athletes (2 wrestlers, 7 sprinters and 1 thrower, aged 20-24 yr, mean age 22.30 ± 1.25 yr) participated in this study. The subjects were tested three times [3 days before the beginning of Ramadan (Pre-RF), the last 3 days of Ramadan (End-RF) and the last 3 days of the 4(th) week after the end of Ramadan (After-RF)]. Anaerobic power and capacity were measured by using the Wingate Anaerobic Test (WAnT) at Pre-RF, End-RF and After- RF. Capillary blood samples for lactate analyses and heart rate recordings were taken at rest, immediately after WAnT and throughout the recovery period. Repeated measures of ANOVA indicated that there were no significant changes in body weight, body mass index, fat free mass, percentage of body fat, daily sleeping time and daily caloric intake associated with Ramadan fasting. No significant changes were found in total body water either, but urinary density measured at End-RF was significantly higher than After-RF. Similarity among peak HR and peak LA values at Pre-RF, End- RF and After-RF demonstrated that cardiovascular and metabolic stress caused by WAnT was not affected by Ramadan fasting. In addition, no influence of Ramadan fasting on anaerobic power and capacity and removal rate of LA from blood following high intensity exercise was observed. The results of this study revealed that if strength-power training is performed regularly and daily food intake, body fluid balance and daily sleeping time are maintained as before Ramadan, Ramadan fasting will not have adverse effects on body composition, anaerobic power and capacity, and LA metabolism during and after high intensity exercise in power athletes. Key pointsNo significant changes were assessed on body composition, daily sleeping time and caloric intake, and body fluid balance in regularly trained power athletes during Ramadan fasting.Ramadan fasting has no adverse effect on power outputs of short time high intensity exercise.No influence of Ramadan fasting on LA metabolism during high intensity exercise and passive recovery in regularly trained power athletes.

Are the oxygen uptake and heart rate off-kinetics influenced by the intensity of prior exercise?

PubMed

do Nascimento Salvador, Paulo Cesar; de Aguiar, Rafael Alves; Teixeira, Anderson Santiago; Souza, Kristopher Mendes de; de Lucas, Ricardo Dantas; Denadai, Benedito Sérgio; Guglielmo, Luiz Guilherme Antonacci

2016-08-01

The aim of this study was to investigate the effect of prior exercise on the heart rate (HR) and oxygen uptake (VO2) off-kinetics after a subsequent high-intensity running exercise. Thirteen male futsal players (age 22.8±6.1years) performed a series of high-intensity bouts without prior exercise (control), preceded by a prior same intensity continuous exercise (CE+CE) and a prior sprint exercise (SE+CE). The magnitude of excess post-exercise oxygen consumption (EPOCm-4.25±0.19 vs. 3.69±0.20Lmin(-1) in CE+CE and 3.62±0.18Lmin(-1) in control; p<0.05) and the parasympathetic reactivation (HRR60s-33±3 vs. 37±3bpm in CE+CE and 42±3 bpm in control; p<0.05) in the SE+CE were higher and slower, compared with another two conditions. The EPOCτ (time to attain 63% of total response; 53±2s) and the heart rate time-course (HRτ-86±5s) were significantly longer after the SE+CE condition than control transition (48±2s and 69±5s, respectively; p<0.05). The SE+CE induce greater stress on the metabolic function, respiratory system and autonomic nervous system regulation during post-exercise recovery than CE, highlighting that the inclusion of sprint-based exercises can be an effective strategy to increase the total energy expenditure following an exercise session. Copyright © 2016 Elsevier B.V. All rights reserved.

Cancer and Exercise: Warburg Hypothesis, Tumour Metabolism and High-Intensity Anaerobic Exercise.

PubMed

Hofmann, Peter

2018-01-31

There is ample evidence that regular moderate to vigorous aerobic physical activity is related to a reduced risk for various forms of cancer to suggest a causal relationship. Exercise is associated with positive changes in fitness, body composition, and physical functioning as well as in patient-reported outcomes such as fatigue, sleep quality, or health-related quality of life. Emerging evidence indicates that exercise may also be directly linked to the control of tumour biology through direct effects on tumour-intrinsic factors. Beside a multitude of effects of exercise on the human body, one underscored effect of exercise training is to target the specific metabolism of tumour cells, namely the Warburg-type highly glycolytic metabolism. Tumour metabolism as well as the tumour⁻host interaction may be selectively influenced by single bouts as well as regularly applied exercise, dependent on exercise intensity, duration, frequency and mode. High-intensity anaerobic exercise was shown to inhibit glycolysis and some studies in animals showed that effects on tumour growth might be stronger compared with moderate-intensity aerobic exercise. High-intensity exercise was shown to be safe in patients; however, it has to be applied carefully with an individualized prescription of exercise.

Do Changes in Tympanic Temperature Predict Changes in Affective Valence during High-Intensity Exercise?

ERIC Educational Resources Information Center

Legrand, Fabien D.; Joly, Philippe M.; Bertucci, William M.

2015-01-01

Purpose: Increased core (brain or body) temperature that accompanies exercise has been posited to play an influential role in affective responses to exercise. However, findings in support of this hypothesis have been equivocal, and most of the performed studies have been done in relation to anxiety. The aim of the present study was to investigate…

The effect of badminton-specific exercise on badminton short-serve performance in competition and practice climates.

PubMed

Duncan, Michael J; Chan, Cheryl K Y; Clarke, Neil D; Cox, Martin; Smith, Mike

2017-03-01

This study examined the effects of changes in physiological and psychological arousal on badminton short-serve performance in competitive and practice climates. Twenty competitive badminton players (10 males and 10 females) volunteered to participate in the study following ethics approval. After familiarisation, badminton short-serve performance was measured at rest, mid-way through and at the end of a badminton-specific exercise protocol in two conditions; competition vs. practice. Ratings of cognitive and somatic anxiety were assessed at three time points prior to badminton short-serve performance using the Mental Readiness Form 3. Heart rate and rating of perceived exertion (RPE) were assessed during the exercise protocol. Results indicated that better short-serve performance was evident in practice compared to competition (P = .034). RPE values were significantly higher in the competition condition compared to practice (P = .007). Cognitive anxiety intensity was significantly lower post-exercise in the practice condition compared to competition (P = .001). Cognitive anxiety direction showed greater debilitation post-exercise in the competition condition compared to practice (P = .01). Somatic anxiety intensity increased from pre-, to mid- to post-exercise (P = .001) irrespective of condition. This study suggests that badminton serve performance is negatively affected when physiological arousal, via badminton-specific exercise, and cognitive anxiety, via perceived competition, are high.

Evidence based exercise - clinical benefits of high intensity interval training.

PubMed

Shiraev, Tim; Barclay, Gabriella

2012-12-01

Aerobic exercise has a marked impact on cardiovascular disease risk. Benefits include improved serum lipid profiles, blood pressure and inflammatory markers as well as reduced risk of stroke, acute coronary syndrome and overall cardiovascular mortality. Most exercise programs prescribed for fat reduction involve continuous, moderate aerobic exercise, as per Australian Heart Foundation clinical guidelines. This article describes the benefits of exercise for patients with cardiovascular and metabolic disease and details the numerous benefits of high intensity interval training (HIIT) in particular. Aerobic exercise has numerous benefits for high-risk populations and such benefits, especially weight loss, are amplified with HIIT. High intensity interval training involves repeatedly exercising at a high intensity for 30 seconds to several minutes, separated by 1-5 minutes of recovery (either no or low intensity exercise). HIT is associated with increased patient compliance and improved cardiovascular and metabolic outcomes and is suitable for implementation in both healthy and 'at risk' populations. Importantly, as some types of exercise are contraindicated in certain patient populations and HIIT is a complex concept for those unfamiliar to exercise, some patients may require specific assessment or instruction before commencing a HIIT program.

Training Performed Above Lactate Threshold Decreases p53 and Shelterin Expression in Mice.

PubMed

de Carvalho Cunha, Verusca Najara; Dos Santos Rosa, Thiago; Sales, Marcelo Magalhães; Sousa, Caio Victor; da Silva Aguiar, Samuel; Deus, Lysleine Alves; Simoes, Herbert Gustavo; de Andrade, Rosangela Vieira

2018-06-26

Telomere shortening is associated to sarcopenia leading to functional impairment during aging. There are mechanisms associated with telomere attrition, as well to its protection and repair. Physical training is a factor that attenuates telomere shortening, but little is known about the effects of different exercise intensities on telomere biology. Thus, we evaluated the effects of exercise intensity (moderate vs. high-intensity domain) on gene expression of senescence markers Checkpoint kinase 2 and tumor suppressor ( Chk2 and p53 , respectively), shelterin telomere repeat binding 1 and 2 ( Trf1 / Trf2 ), DNA repair ( Xrcc5 ), telomerase reverse transcriptase ( mTERT ) and telomere length in middle aged mice. Three groups were studied: a control group (CTL) and two groups submitted to swimming at intensities below the lactate threshold (LI group) and above the lactate threshold (HI group) for 40 and 20 min respectively, for 12 weeks. After training, the HI group showed reduction in p53 expression in the muscle, and decreased shelterin complex expression when compared to LI group. No differences were observed between groups for mTERT expression and telomere length. Thus, exercise training in high-intensity domain was more effective on reducing markers of senescence and apoptosis. The higher intensity exercise training also diminished shelterin expression, with no differences in telomere length and mTERT expression. Such results possibly indicate a more effective DNA protection for the higher-intensity exercise training. © Georg Thieme Verlag KG Stuttgart · New York.

The Effects of Acute Exercise on Memory and Brain-Derived Neurotrophic Factor (BDNF).

PubMed

Etnier, Jennifer L; Wideman, Laurie; Labban, Jeffrey D; Piepmeier, Aaron T; Pendleton, Daniel M; Dvorak, Kelly K; Becofsky, Katie

2016-08-01

Acute exercise benefits cognition, and some evidence suggests that brain-derived neurotrophic factor (BDNF) plays a role in this effect. The purpose of this study was to explore the dose-response relationship between exercise intensity, memory, and BDNF. Young adults completed 3 exercise sessions at different intensities relative to ventilator threshold (Vt) (VO 2max , Vt - 20%, Vt + 20%). For each session, participants exercised for approximately 30 min. Following exercise, they performed the Rey Auditory Verbal Learning Test (RAVLT) to assess short-term memory, learning, and long-term memory recall. Twenty-four hours later, they completed the RAVLT recognition trial, which provided another measure of long-term memory. Blood was drawn before exercise, immediately postexercise, and after the 30-min recall test. Results indicated that long-term memory as assessed after the 24-hr delay differed as a function of exercise intensity with the largest benefits observed following maximal intensity exercise. BDNF data showed a significant increase in response to exercise; however, there were no differences relative to exercise intensity and there were no significant associations between BDNF and memory. Future research is warranted so that we can better understand how to use exercise to benefit cognitive performance.

The Acute Effect of Exercise Intensity on Vascular Function in Adolescents.

PubMed

Bond, Bert; Hind, Siobhan; Williams, Craig A; Barker, Alan R

2015-12-01

Impairments in vascular function are present in asymptomatic youths with risk factors for cardiovascular disease. Exercise can promote vascular health in youth, but the effects of exercise intensity and the time course in response to acute exercise are unknown. Twenty adolescents (10 male, 14.1 ± 0.3 yr) performed the following on separate days in a counterbalanced order: 1) cycling at 90% of the gas exchange threshold (moderate-intensity exercise (MIE)) and 2) 8 × 1-min cycling at 90% peak power with 75-s recovery (high-intensity interval exercise (HIIE)). The duration of MIE (25.8 ± 2.1 min) was work-matched to HIIE (23.0 min). Macro- and microvascular functions were assessed before, immediately after, and 1 and 2 h after exercise by flow-mediated dilation (FMD) and laser Doppler imaging (total reactive hyperemia). FMD was attenuated immediately after HIIE (P < 0.001, effect size (ES) = 1.20) but not after MIE (P = 0.28, ES = 0.26). Compared with that before exercise, FMD was elevated 1 and 2 h after HIIE (P < 0.001, ES = 1.33; P < 0.001, ES = 1.36) but unchanged in MIE (P = 0.67, ES = 0.10; P = 0.72, ES = 0.08). Changes in FMD were unrelated to shear or baseline arterial diameter. Compared with that in preexercise, total reactive hyperemia was always greater after MIE (P < 0.02, ES > 0.60 for all) and HIIE (P < 0.001, ES > 1.18 for all). Total reactive hyperemia was greater in HIIE compared with that in MIE immediately after (P = 0.03, ES = 0.67) and 1 h after (P = 0.01, ES = 0.62) exercise, with a trend to be greater 2 h after (P = 0.06, ES = 0.45). Exercise intensity is positively associated with macro- and microvascular function 1 and 2 h after exercise. Performing HIIE may provide superior vascular benefits than MIE in adolescents.

Effect of High-Intensity Treadmill Exercise on Motor Symptoms in Patients With De Novo Parkinson Disease: A Phase 2 Randomized Clinical Trial.

PubMed

Schenkman, Margaret; Moore, Charity G; Kohrt, Wendy M; Hall, Deborah A; Delitto, Anthony; Comella, Cynthia L; Josbeno, Deborah A; Christiansen, Cory L; Berman, Brian D; Kluger, Benzi M; Melanson, Edward L; Jain, Samay; Robichaud, Julie A; Poon, Cynthia; Corcos, Daniel M

2018-02-01

Parkinson disease is a progressive neurologic disorder. Limited evidence suggests endurance exercise modifies disease severity, particularly high-intensity exercise. To examine the feasibility and safety of high-intensity treadmill exercise in patients with de novo Parkinson disease who are not taking medication and whether the effect on motor symptoms warrants a phase 3 trial. The Study in Parkinson Disease of Exercise (SPARX) was a phase 2, multicenter randomized clinical trial with 3 groups and masked assessors. Individuals from outpatient and community-based clinics were enrolled from May 1, 2012, through November 30, 2015, with the primary end point at 6 months. Individuals with idiopathic Parkinson disease (Hoehn and Yahr stages 1 or 2) aged 40 to 80 years within 5 years of diagnosis who were not exercising at moderate intensity greater than 3 times per week and not expected to need dopaminergic medication within 6 months participated in this study. A total of 384 volunteers were screened by telephone; 128 were randomly assigned to 1 of 3 groups (high-intensity exercise, moderate-intensity exercise, or control). High-intensity treadmill exercise (4 days per week, 80%-85% maximum heart rate [n = 43]), moderate-intensity treadmill exercise (4 days per week, 60%-65% maximum heart rate [n = 45]), or wait-list control (n = 40) for 6 months. Feasibility measures were adherence to prescribed heart rate and exercise frequency of 3 days per week and safety. The clinical outcome was 6-month change in Unified Parkinson's Disease Rating Scale motor score. A total of 128 patients were included in the study (mean [SD] age, 64 [9] years; age range, 40-80 years; 73 [57.0%] male; and 108 [84.4%] non-Hispanic white). Exercise rates were 2.8 (95% CI, 2.4-3.2) days per week at 80.2% (95% CI, 78.8%-81.7%) maximum heart rate in the high-intensity group and 3.2 (95% CI, 2.8-3.6; P = .13) days per week at 65.9% (95% CI, 64.2%-67.7%) maximum heart rate in the moderate-intensity group (P < .001). The mean change in Unified Parkinson's Disease Rating Scale motor score in the high-intensity group was 0.3 (95% CI, -1.7 to 2.3) compared with 3.2 (95% CI, 1.4 to 5.1) in the usual care group (P = .03). The high-intensity group, but not the moderate-intensity group, reached the predefined nonfutility threshold compared with the control group. Anticipated adverse musculoskeletal events were not severe. High-intensity treadmill exercise may be feasible and prescribed safely for patients with Parkinson disease. An efficacy trial is warranted to determine whether high-intensity treadmill exercise produces meaningful clinical benefits in de novo Parkinson disease. clinicaltrials.gov Identifier: NCT01506479.

Repeated high-intensity exercise in professional rugby union.

PubMed

Austin, Damien; Gabbett, Tim; Jenkins, David

2011-07-01

The aim of the present study was to describe the frequency, duration, and nature of repeated high-intensity exercise in Super 14 rugby union. Time-motion analysis was used during seven competition matches over the 2008 and 2009 Super 14 seasons; five players from each of four positional groups (front row forwards, back row forwards, inside backs, and outside backs) were assessed (20 players in total). A repeated high-intensity exercise bout was considered to involve three or more sprints, and/or tackles and/or scrum/ruck/maul activities within 21 s during the same passage of play. The range of repeated high-intensity exercise bouts for each group in a match was as follows: 11-18 for front row forwards, 11-21 for back row forwards, 13-18 for inside backs, and 2-11 for outside backs. The durations of the most intense repeated high-intensity exercise bouts for each position ranged from 53 s to 165 s and the minimum recovery periods between repeated high-intensity exercise bouts ranged from 25 s for the back row forwards to 64 s for the front row forwards. The present results show that repeated high-intensity exercise bouts vary in duration and activities relative to position but all players in a game will average at least 10 changes in activity in the most demanding bouts and complete at least one tackle and two sprints. The most intense periods of activity are likely to last as long as 120 s and as little as 25 s recovery may separate consecutive repeated high-intensity exercise bouts. The present findings can be used by coaches to prepare their players for the most demanding passages of play likely to be experienced in elite rugby union.

Is there a minimum intensity threshold for resistance training-induced hypertrophic adaptations?

PubMed

Schoenfeld, Brad J

2013-12-01

In humans, regimented resistance training has been shown to promote substantial increases in skeletal muscle mass. With respect to traditional resistance training methods, the prevailing opinion is that an intensity of greater than ~60 % of 1 repetition maximum (RM) is necessary to elicit significant increases in muscular size. It has been surmised that this is the minimum threshold required to activate the complete spectrum of fiber types, particularly those associated with the largest motor units. There is emerging evidence, however, that low-intensity resistance training performed with blood flow restriction (BFR) can promote marked increases in muscle hypertrophy, in many cases equal to that of traditional high-intensity exercise. The anabolic effects of such occlusion-based training have been attributed to increased levels of metabolic stress that mediate hypertrophy at least in part by enhancing recruitment of high-threshold motor units. Recently, several researchers have put forth the theory that low-intensity exercise (≤50 % 1RM) performed without BFR can promote increases in muscle size equal, or perhaps even superior, to that at higher intensities, provided training is carried out to volitional muscular failure. Proponents of the theory postulate that fatiguing contractions at light loads is simply a milder form of BFR and thus ultimately results in maximal muscle fiber recruitment. Current research indicates that low-load exercise can indeed promote increases in muscle growth in untrained subjects, and that these gains may be functionally, metabolically, and/or aesthetically meaningful. However, whether hypertrophic adaptations can equal that achieved with higher intensity resistance exercise (≤60 % 1RM) remains to be determined. Furthermore, it is not clear as to what, if any, hypertrophic effects are seen with low-intensity exercise in well-trained subjects as experimental studies on the topic in this population are lacking. Practical implications of these findings are discussed.

Effect of voluntary hypocapnic hyperventilation or moderate hypoxia on metabolic and heart rate responses during high-intensity intermittent exercise.

PubMed

Dobashi, Kohei; Fujii, Naoto; Watanabe, Kazuhito; Tsuji, Bun; Sasaki, Yosuke; Fujimoto, Tomomi; Tanigawa, Satoru; Nishiyasu, Takeshi

2017-08-01

To investigate the effect of voluntary hypocapnic hyperventilation or moderate hypoxia on metabolic and heart rate responses during high-intensity intermittent exercise. Ten males performed three 30-s bouts of high-intensity cycling [Ex1 and Ex2: constant-workload at 80% of the power output in the Wingate anaerobic test (WAnT), Ex3: WAnT] interspaced with 4-min recovery periods under normoxic (Control), hypocapnic or hypoxic (2500 m) conditions. Hypocapnia was developed through voluntary hyperventilation for 20 min prior to Ex1 and during each recovery period. End-tidal CO 2 pressure was lower before each exercise in the hypocapnia than control trials. Oxygen uptake ([Formula: see text]) was lower in the hypocapnia than control trials (822 ± 235 vs. 1645 ± 245 mL min -1 ; mean ± SD) during Ex1, but not Ex2 or Ex3, without a between-trial difference in the power output during the exercises. Heart rates (HRs) during Ex1 (127 ± 8 vs. 142 ± 10 beats min -1 ) and subsequent post-exercise recovery periods were lower in the hypocapnia than control trials, without differences during or after Ex2, except at 4 min into the second recovery period. [Formula: see text] did not differ between the control and hypoxia trials throughout. These results suggest that during three 30-s bouts of high-intensity intermittent cycling, (1) hypocapnia reduces the aerobic metabolic rate with a compensatory increase in the anaerobic metabolic rate during the first but not subsequent exercises; (2) HRs during the exercise and post-exercise recovery periods are lowered by hypocapnia, but this effect is diminished with repeated exercise bouts, and (3) moderate hypoxia (2500 m) does not affect the metabolic response during exercise.

Fatigue Exacerbation by Interval or Continuous Exercise in Chronic Fatigue Syndrome.

PubMed

Sandler, Carolina X; Lloyd, Andrew R; Barry, Benjamin K

2016-10-01

The objective of this study is to determine whether the typical exacerbation of symptoms in patients with chronic fatigue syndrome (CFS) after a bout of exercise differs between high-intensity interval training (HIIT) or continuous (CONT) aerobic exercise of the same duration and mechanical work. Participants with specialist-diagnosed CFS performed two 20-min bouts of cycling in a randomized crossover study. The bouts were either moderate-intensity continuous (70% age-predicted HR maximum) or high-intensity interval exercise, separated by at least 2 wk. Self-report questionnaires capturing fatigue, the related symptoms, and actigraphy were collected across 2 d before and 4 d after the exercise. Comparisons between exercise bouts were made using paired sample t-tests. Fourteen moderately affected participants who were unable to work, but not bed bound, completed the study (nine female, 32 ± 10 yr, 67 ± 11 kg). Mechanical work was matched successfully between the exercise bouts (HIIT, 83,037, vs CONT, 83,348 J, P = 0.84). Mean HR (HIIT, 76% ± 5%, vs CONT, 73% ± 6% age-predicted HR maximum, P < 0.05) and RPE (6-20) in the legs (HIIT, 15.4 ± 1.4, vs CONT, 13.2 ± 1.2, P < 0.001) were higher for the interval compared with continuous exercise. Mean fatigue scores (0-10) were similar before each exercise challenge (HIIT, 4.5 ± 1.8, vs CONT, 4.1 ± 1.7, P = 0.43). Participants reported an increase in fatigue scores after both challenges (mean difference: HIIT, 1.0 ± 1.3, P < 0.01; CONT, 1.5 ± 0.7, P < 0.001), but these exacerbations in fatigue were not statistically or clinically different (P = 0.20). High-intensity interval exercise did not exacerbate fatigue any more than continuous exercise of comparable workload. This finding supports evaluation of HIIT in graded exercise therapy interventions for patients with CFS.

Effects of High-Intensity Interval Exercise versus Moderate Continuous Exercise on Glucose Homeostasis and Hormone Response in Patients with Type 1 Diabetes Mellitus Using Novel Ultra-Long-Acting Insulin

PubMed Central

Mueller, Alexander; Groeschl, Werner; Pieber, Thomas R.; Obermayer-Pietsch, Barbara; Koehler, Gerd; Hofmann, Peter

2015-01-01

Introduction We investigated blood glucose (BG) and hormone response to aerobic high-intensity interval exercise (HIIE) and moderate continuous exercise (CON) matched for mean load and duration in type 1 diabetes mellitus (T1DM). Material and Methods Seven trained male subjects with T1DM performed a maximal incremental exercise test and HIIE and CON at 3 different mean intensities below (A) and above (B) the first lactate turn point and below the second lactate turn point (C) on a cycle ergometer. Subjects were adjusted to ultra-long-acting insulin Degludec (Tresiba/ Novo Nordisk, Denmark). Before exercise, standardized meals were administered, and short-acting insulin dose was reduced by 25% (A), 50% (B), and 75% (C) dependent on mean exercise intensity. During exercise, BG, adrenaline, noradrenaline, dopamine, cortisol, glucagon, and insulin-like growth factor-1, blood lactate, heart rate, and gas exchange variables were measured. For 24 h after exercise, interstitial glucose was measured by continuous glucose monitoring system. Results BG decrease during HIIE was significantly smaller for B (p = 0.024) and tended to be smaller for A and C compared to CON. No differences were found for post-exercise interstitial glucose, acute hormone response, and carbohydrate utilization between HIIE and CON for A, B, and C. In HIIE, blood lactate for A (p = 0.006) and B (p = 0.004) and respiratory exchange ratio for A (p = 0.003) and B (p = 0.003) were significantly higher compared to CON but not for C. Conclusion Hypoglycemia did not occur during or after HIIE and CON when using ultra-long-acting insulin and applying our methodological approach for exercise prescription. HIIE led to a smaller BG decrease compared to CON, although both exercises modes were matched for mean load and duration, even despite markedly higher peak workloads applied in HIIE. Therefore, HIIE and CON could be safely performed in T1DM. Trial Registration ClinicalTrials.gov NCT02075567 http://www.clinicaltrials.gov/ct2/show/NCT02075567 PMID:26317981

Potential adverse cardiac remodelling in highly trained athletes: still unknown clinical significance.

PubMed

Gabrielli, Luigi; Sitges, Marta; Chiong, Mario; Jalil, Jorge; Ocaranza, María; Llevaneras, Silvana; Herrera, Sebastian; Fernandez, Rodrigo; Saavedra, Rodrigo; Yañez, Fernando; Vergara, Luis; Diaz, Alexis; Lavandero, Sergio; Castro, Pablo

2018-06-12

Moderate endurance exercise has long been considered an essential element to maintain cardiovascular health, and sedentary behaviour in the general population has been related to a significant increase in all-causes of mortality, cardiovascular disease mortality and cardiovascular disease incidence. However, a growing group of people performs an intense exercise that leads to multiple heart adaptive changes that are collectively called "athlete's heart". In this review, we discussed the evidence of cardiac remodelling process secondary to repetitive and strenuous exercise in some predisposed athletes that produces intense and probably deleterious changes in cardiac morphology and function with no clear clinical significance in long-term follow-up. Moreover, we also discussed the individual biological response to exercise assessed by myocardial damage, inflammation, oxidative stress, fibrosis and ventricular hypertrophy biomarkers showing different intensities with equivalent exertion.

Randomized controlled trial evaluating the temporal effects of high-intensity exercise on learning, short-term and long-term memory, and prospective memory.

PubMed

Frith, Emily; Sng, Eveleen; Loprinzi, Paul D

2017-11-01

The broader purpose of this study was to examine the temporal effects of high-intensity exercise on learning, short-term and long-term retrospective memory and prospective memory. Among a sample of 88 young adult participants, 22 were randomized into one of four different groups: exercise before learning, control group, exercise during learning, and exercise after learning. The retrospective assessments (learning, short-term and long-term memory) were assessed using the Rey Auditory Verbal Learning Test. Long-term memory including a 20-min and 24-hr follow-up assessment. Prospective memory was assessed using a time-based procedure by having participants contact (via phone) the researchers at a follow-up time period. The exercise stimulus included a 15-min bout of progressive maximal exertion treadmill exercise. High-intensity exercise prior to memory encoding (vs. exercise during memory encoding or consolidation) was effective in enhancing long-term memory (for both 20-min and 24-h follow-up assessments). We did not observe a differential temporal effect of high-intensity exercise on short-term memory (immediate post-memory encoding), learning or prospective memory. The timing of high-intensity exercise may play an important role in facilitating long-term memory. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

A DIGE proteomic analysis for high-intensity exercise-trained rat skeletal muscle.

PubMed

Yamaguchi, Wataru; Fujimoto, Eri; Higuchi, Mitsuru; Tabata, Izumi

2010-09-01

Exercise training induces various adaptations in skeletal muscles. However, the mechanisms remain unclear. In this study, we conducted 2D-DIGE proteomic analysis, which has not yet been used for elucidating adaptations of skeletal muscle after high-intensity exercise training (HIT). For 5 days, rats performed HIT, which consisted of 14 20-s swimming exercise bouts carrying a weight (14% of the body weight), and 10-s pause between bouts. The 2D-DIGE analysis was conducted on epitrochlearis muscles excised 18 h after the final training exercise. Proteomic profiling revealed that out of 800 detected and matched spots, 13 proteins exhibited changed expression by HIT compared with sedentary rats. All proteins were identified by MALDI-TOF/MS. Furthermore, using western immunoblot analyses, significantly changed expressions of NDUFS1 and parvalbumin (PV) were validated in relation to HIT. In conclusion, the proteomic 2D-DIGE analysis following HIT-identified expressions of NDUFS1 and PV, previously unknown to have functions related to exercise-training adaptations.

Miniature Biometric Sensor Project

NASA Technical Reports Server (NTRS)

Falker, John; Terrier, Douglas; Clayton, Ronald; Hanson, Andrea; Cooper, Tommy; Downs, Meghan; Flint, Stephanie; Reyna, Baraquiel; Simon, Cory; Wilt, Grier

2015-01-01

Heart rate monitoring (HRM) is a critical need during exploration missions. Unlike the four separate systems used on ISS today, the single HRM system should perform as a diagnostic tool, perform well during exercise or high level activity, and be suitable for use during EVA. Currently available HRM technologies are dependent on uninterrupted contact with the skin and are prone to data drop-out and motion artifact when worn in the spacesuit or during exercise. Here, we seek an alternative to the chest strap and electrode based sensors currently in use on ISS today. This project aims to develop a single, high performance, robust biosensor with focused efforts on improved heart rate data quality collection during high intensity activity such as exercise or EVA.

Effects of high-intensity interval cycling performed after resistance training on muscle strength and hypertrophy.

PubMed

Tsitkanou, S; Spengos, K; Stasinaki, A-N; Zaras, N; Bogdanis, G; Papadimas, G; Terzis, G

2017-11-01

Aim of the study was to investigate whether high-intensity interval cycling performed immediately after resistance training would inhibit muscle strength increase and hypertrophy expected from resistance training per se. Twenty-two young men were assigned into either resistance training (RE; N = 11) or resistance training plus high-intensity interval cycling (REC; N = 11). Lower body muscle strength and rate of force development (RFD), quadriceps cross-sectional area (CSA) and vastus lateralis muscle architecture, muscle fiber type composition and capillarization, and estimated aerobic capacity were evaluated before and after 8 weeks of training (2 times per week). Muscle strength and quadriceps CSA were significantly and similarly increased after both interventions. Fiber CSA increased significantly and similarly after both RE (type I: 13.6 ± 3.7%, type IIA: 17.6 ± 4.4%, type IIX: 23.2 ± 5.7%, P < 0.05) and REC (type I: 10.0 ± 2.7%, type IIA: 14.8 ± 4.3% type IIX: 20.8 ± 6.0%, P < 0.05). In contrast, RFD decreased and fascicle angle increased (P < 0.05) only after REC. Capillary density and estimated aerobic capacity increased (P < 0.05) only after REC. These results suggest that high-intensity interval cycling performed after heavy-resistance exercise may not inhibit resistance exercise-induced muscle strength/hypertrophy after 2 months of training, while it prompts aerobic capacity and muscle capillarization. The addition of high-intensity cycling after heavy-resistance exercise may decrease RFD partly due to muscle architectural changes. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

High-Intensity Locomotor Exercise Increases Brain-Derived Neurotrophic Factor in Individuals with Incomplete Spinal Cord Injury.

PubMed

Leech, Kristan A; Hornby, T George

2017-03-15

High-intensity locomotor exercise is suggested to contribute to improved recovery of locomotor function after neurological injury. This may be secondary to exercise-intensity-dependent increases in neurotrophin expression demonstrated previously in control subjects. However, rigorous examination of intensity-dependent changes in neurotrophin levels is lacking in individuals with motor incomplete spinal cord injury (SCI). Therefore, the primary aim of this study was to evaluate the effect of locomotor exercise intensity on peripheral levels of brain-derived neurotrophic factor (BDNF) in individuals with incomplete SCI. We also explored the impact of the Val66Met single-nucleotide polymorphism (SNP) on the BDNF gene on intensity-dependent changes. Serum concentrations of BDNF and insulin-like growth factor-1 (IGF-1), as well as measures of cardiorespiratory dynamics, were evaluated across different levels of exercise intensity achieved during a graded-intensity, locomotor exercise paradigm in 11 individuals with incomplete SCI. Our results demonstrate a significant increase in serum BDNF at high, as compared to moderate, exercise intensities (p = 0.01) and 15 and 30 min post-exercise (p < 0.01 for both), with comparison to changes at low intensity approaching significance (p = 0.05). Serum IGF-1 demonstrated no intensity-dependent changes. Significant correlations were observed between changes in BDNF and specific indicators of exercise intensity (e.g., rating of perceived exertion; R = 0.43; p = 0.02). Additionally, the data suggest that Val66Met SNP carriers may not exhibit intensity-dependent changes in serum BDNF concentration. Given the known role of BDNF in experience-dependent neuroplasticity, these preliminary results suggest that exercise intensity modulates serum BDNF concentrations and may be an important parameter of physical rehabilitation interventions after neurological injury.

Influence of aerobic exercise intensity on myofibrillar and mitochondrial protein synthesis in young men during early and late postexercise recovery.

PubMed

Di Donato, Danielle M; West, Daniel W D; Churchward-Venne, Tyler A; Breen, Leigh; Baker, Steven K; Phillips, Stuart M

2014-05-01

Aerobic exercise is typically associated with expansion of the mitochondrial protein pool and improvements in muscle oxidative capacity. The impact of aerobic exercise intensity on the synthesis of specific skeletal muscle protein subfractions is not known. We aimed to study the effect of aerobic exercise intensity on rates of myofibrillar (MyoPS) and mitochondrial (MitoPS) protein synthesis over an early (0.5-4.5 h) and late (24-28 h) period during postexercise recovery. Using a within-subject crossover design, eight males (21 ± 1 yr, Vo2peak 46.7 ± 2.0 ml·kg(-1)·min(-1)) performed two work-matched cycle ergometry exercise trials (LOW: 60 min at 30% Wmax; HIGH: 30 min at 60% Wmax) in the fasted state while undergoing a primed constant infusion of l-[ring-(13)C6]phenylalanine. Muscle biopsies were obtained at rest and 0.5, 4.5, 24, and 28 h postexercise to determine both the "early" and "late" response of MyoPS and MitoPS and the phosphorylation status of selected proteins within both the Akt/mTOR and MAPK pathways. Over 24-28 h postexercise, MitoPS was significantly greater after the HIGH vs. LOW exercise trial (P < 0.05). Rates of MyoPS were increased equivalently over 0.5-4.5 h postexercise recovery (P < 0.05) but remained elevated at 24-28 h postexercise only following the HIGH trial. In conclusion, an acute bout of high- but not low-intensity aerobic exercise in the fasted state resulted in a sustained elevation of both MitoPS and MyoPS at 24-28 h postexercise recovery.

Influence of aerobic exercise intensity on myofibrillar and mitochondrial protein synthesis in young men during early and late postexercise recovery

PubMed Central

Di Donato, Danielle M.; West, Daniel W. D.; Churchward-Venne, Tyler A.; Breen, Leigh; Baker, Steven K.

2014-01-01

Aerobic exercise is typically associated with expansion of the mitochondrial protein pool and improvements in muscle oxidative capacity. The impact of aerobic exercise intensity on the synthesis of specific skeletal muscle protein subfractions is not known. We aimed to study the effect of aerobic exercise intensity on rates of myofibrillar (MyoPS) and mitochondrial (MitoPS) protein synthesis over an early (0.5–4.5 h) and late (24–28 h) period during postexercise recovery. Using a within-subject crossover design, eight males (21 ± 1 yr, V̇o2peak 46.7 ± 2.0 ml·kg−1·min−1) performed two work-matched cycle ergometry exercise trials (LOW: 60 min at 30% Wmax; HIGH: 30 min at 60% Wmax) in the fasted state while undergoing a primed constant infusion of l-[ring-13C6]phenylalanine. Muscle biopsies were obtained at rest and 0.5, 4.5, 24, and 28 h postexercise to determine both the “early” and “late” response of MyoPS and MitoPS and the phosphorylation status of selected proteins within both the Akt/mTOR and MAPK pathways. Over 24–28 h postexercise, MitoPS was significantly greater after the HIGH vs. LOW exercise trial (P < 0.05). Rates of MyoPS were increased equivalently over 0.5–4.5 h postexercise recovery (P < 0.05) but remained elevated at 24–28 h postexercise only following the HIGH trial. In conclusion, an acute bout of high- but not low-intensity aerobic exercise in the fasted state resulted in a sustained elevation of both MitoPS and MyoPS at 24–28 h postexercise recovery. PMID:24595306

Effects of a high-intensity functional exercise programme on depressive symptoms and psychological well-being among older people living in residential care facilities: A cluster-randomized controlled trial.

PubMed

Conradsson, Mia; Littbrand, Håkan; Lindelof, Nina; Gustafson, Yngve; Rosendahl, Erik

2010-07-01

To evaluate the effects of a high-intensity functional exercise programme on depressive symptoms and psychological well-being among older people dependent in activities of daily living (ADL) and living in residential care facilities. Cluster-randomized controlled study. Participants were 191 older people, aged 65-100, dependent in ADL and with Mini Mental State Examination scores between 10 and 30. One-hundred (52%) of the participants had a diagnosed dementia disorder. A high-intensity functional weight-bearing exercise programme and a control activity were performed in groups. Sessions were held five times over each two week period for three months, a total of 29 times. The outcome measures, Geriatric Depression Scale (GDS-15) and Philadelphia Geriatric Center Morale Scale (PGCMS) were blindly assessed at baseline, three and six months. At baseline, mean +/- SD (range) for GDS was 4.4 +/- 3.2 (0-14), and for PGCMS 11.0 +/- 3.5 (2-17). There were no significant differences in GDS or PGCMS between the exercise and the control group at the three and six month follow-ups in the total sample. Among people with dementia, there was a between-group difference at three months in PGCMS scores in favour of the exercise group. A high-intensity functional exercise programme seems generally not to influence depressive symptoms or psychological well-being among older people dependent in ADL and living in residential care facilities. An individualized and multifactorial intervention may be needed in this group. However, an exercise programme as a single intervention may have a short-term effect on well-being among people with dementia.

Protocol, and practical challenges, for a randomised controlled trial comparing the impact of high intensity interval training against standard care before major abdominal surgery: study protocol for a randomised controlled trial.

PubMed

Woodfield, John; Zacharias, Matthew; Wilson, Genevieve; Munro, Fran; Thomas, Kate; Gray, Andrew; Baldi, James

2018-06-25

Risk factors, such as the number of pre-existing co-morbidities, the extent of the underlying pathology and the magnitude of the required operation, cannot be changed before surgery. It may, however, be possible to improve the cardiopulmonary fitness of the patient with an individualised exercise program. We are performing a randomised controlled trial (RCT) assessing the impact of High Intensity Interval Training (HIIT) on preoperative cardiopulmonary fitness and postoperative outcomes in patients undergoing major abdominal surgery. Consecutive eligible patients undergoing elective abdominal surgery are being randomised to HIIT or standard care in a 1:1 ratio. Participants allocated to HIIT will perform 14 exercise sessions on a stationary cycle ergometer, over a period of 4-6 weeks before surgery. The sessions, which are individualised, aim to start with ten repeated 1-min blocks of intense exercise with a target of reaching a heart rate exceeding 90% of the age predicted maximum, followed by 1 min of lower intensity cycling. As endurance improves, the duration of exercise is increased to achieve five 2-min intervals of high intensity exercise followed by 2 min of lower intensity cycling. Each training session lasts approximately 30 min. The primary endpoint, change in peak oxygen consumption (Peak VO 2 ) measured during cardiopulmonary exercise testing, is assessed at baseline and before surgery. Secondary endpoints include postoperative complications, length of hospital stay and three clinically validated scores: the surgical recovery scale; the postoperative morbidity survey; and the SF-36 quality of life score. The standard deviation for changes in Peak VO 2 will be assessed after the first 30 patients and will be used to calculate the required sample size. We want to assess if 14 sessions of HIIT is sufficient to improve Peak VO 2 by 2 mL/kg/min in patients undergoing major abdominal surgery and to explore the best clinical endpoint for a subsequent RCT designed to assess if improving Peak VO 2 will translate into improving clinical outcomes after surgery. Australian New Zealand Clinical Trials Registry, ACTRN12617000587303 . Registered on 26 April 2017.

Rate of utilization of a given fraction of W' (the curvature constant of the power-duration relationship) does not affect fatigue during severe-intensity exercise.

PubMed

de Souza, Kristopher Mendes; Dekerle, Jeanne; Salvador, Paulo Cesar do Nascimento; de Lucas, Ricardo Dantas; Guglielmo, Luiz Guilherme Antonacci; Greco, Camila Coelho; Denadai, Benedito Sérgio

2016-04-01

What is the central question of this study? Does the rate of utilization of W' (the curvature constant of the power-duration relationship) affect fatigue during severe-intensity exercise? What is the main finding and its importance? The magnitude of fatigue after two severe-intensity exercises designed to deplete the same fraction of W' (70%) at two different rates of utilization (fast versus slow) was similar after both exercises. Moreover, the magnitude of fatigue was related to critical power (CP), supporting the contention that CP is a key determinant in fatigue development during high-intensity exercise. Thus, the CP model is a suitable approach to investigate fatigue mechanisms during high-intensity exercise. The depletion of W' (the curvature constant of the power-duration relationship) seems to contribute to fatigue during severe-intensity exercise. Therefore, the aim of this study was to determine the effect of a fast versus a slow rate of utilization of W' on the occurrence of fatigue within the severe-intensity domain. Fifteen healthy male subjects performed tests to determine the critical power, W' and peak torque in the control condition (TCON ) and immediately after two fatiguing work rates (THREE and TEN) set to deplete 70% W' in either 3 (TTHREE ) or 10 min (TTEN ). The TTHREE and TTEN were significantly reduced (F = 19.68, P = 0.01) in comparison to TCON . However, the magnitude of reduction in peak torque (TTHREE  = -19.8 ± 10.1% versus TTEN  = -16.8 ± 13.3%) was the same in the two fatiguing exercises (t = -0.76, P = 0.46). There was a significant inverse relationship between the critical power and the reduction in peak torque during both THREE (r = -0.49, P = 0.03) and TEN (r = -0.62, P = 0.02). In contrast, the W' was not significantly correlated with the reduction in peak torque during both THREE (r = -0.14, P = 0.33) and TEN (r = -0.30, P = 0.10). Thus, fatigue following severe-intensity exercises performed at different rates of utilization of W' was similar when the same work was done above the critical power (i.e. same amount of W' used). © 2016 The Authors. Experimental Physiology © 2016 The Physiological Society.

The effects of compression garments on intermittent exercise performance and recovery on consecutive days.

PubMed

Duffield, Rob; Edge, Johann; Merrells, Robert; Hawke, Emma; Barnes, Matt; Simcock, David; Gill, Nicholas

2008-12-01

The aim of this study was to determine whether compression garments improve intermittent-sprint performance and aid performance or self-reported recovery from high-intensity efforts on consecutive days. Following familiarization, 14 male rugby players performed two randomized testing conditions (with or without garments) involving consecutive days of a simulated team sport exercise protocol, separated by 24 h of recovery within each condition and 2 weeks between conditions. Each day involved an 80-min high-intensity exercise circuit, with exercise performance determined by repeated 20-m sprints and peak power on a cart dynamometer (single-man scrum machine). Measures of nude mass, heart rate, skin and tympanic temperature, and blood lactate (La-) were recorded throughout each day; also, creatine kinase (CK) and muscle soreness were recorded each day and 48 h following exercise. No differences (P=.20 to 0.40) were present between conditions on either day of the exercise protocol for repeated 20-m sprint efforts or peak power on a cart dynamometer. Heart rate, tympanic temperature, and body mass did not significantly differ between conditions; however, skin temperature was higher under the compression garments. Although no differences (P=.50) in La- or CK were present, participants felt reduced levels of perceived muscle soreness in the ensuing 48 h postexercise when wearing the garments (2.5+/-1.7 vs 3.5+/-2.1 for garment and control; P=.01). The use of compression garments did not improve or hamper simulated team-sport activity on consecutive days. Despite benefits of reduced self-reported muscle soreness when wearing garments during and following exercise each day, no improvements in performance or recovery were apparent.

Moderating influence of dominant attentional style and exercise intensity on responses to asynchronous music.

PubMed

Hutchinson, Jasmin C; Karageorghis, Costas I

2013-12-01

We examined independent and combined influences of asynchronous music and dominant attentional style (DAS) on psychological and psychophysical variables during exercise using mixed methods. Participants (N = 34) were grouped according to DAS and completed treadmill runs at three intensities (low, moderate, high) crossed with three music conditions (motivational, oudeterous, no-music control). State attentional focus shifted from dissociative to associative with increasing intensity and was most aligned with DAS during moderate-intensity exercise. Both music conditions facilitated dissociation at low-to-moderate intensities. At high exercise intensity, both music conditions were associated with reduced RPE among participants with an associative DAS. Dissociators reported higher RPE overall during moderate and high intensities. Psychological responses were most positive in the motivational condition, followed by oudeterous and control. Findings illustrate the relevance of individual differences in DAS as well as task intensity and duration when selecting music for exercise.

Effects of aerobic training intensity on resting, exercise and post-exercise blood pressure, heart rate and heart-rate variability.

PubMed

Cornelissen, V A; Verheyden, B; Aubert, A E; Fagard, R H

2010-03-01

We aimed to investigate the effects of endurance training intensity (1) on systolic blood pressure (SBP) and heart rate (HR) at rest before exercise, and during and after a maximal exercise test; and (2) on measures of HR variability at rest before exercise and during recovery from the exercise test, in at least 55-year-old healthy sedentary men and women. A randomized crossover study comprising three 10-week periods was performed. In the first and third period, participants exercised at lower or higher intensity (33% or 66% of HR reserve) in random order, with a sedentary period in between. Training programmes were identical except for intensity, and were performed under supervision thrice for 1 h per week. The results show that in the three conditions, that is, at rest before exercise, during exercise and during recovery, we found endurance training at lower and higher intensity to reduce SBP significantly (P<0.05) and to a similar extent. Further, SBP during recovery was, on average, not lower than at rest before exercise, and chronic endurance training did not affect the response of SBP after an acute bout of exercise. The effect of training on HR at rest, during exercise and recovery was more pronounced (P<0.05) with higher intensity. Finally, endurance training had no significant effect on sympathovagal balance. In conclusion, in participants at higher age, both training programmes exert similar effects on SBP at rest, during exercise and during post-exercise recovery, whereas the effects on HR are more pronounced after higher intensity training.

Low- and high-intensity treadmill exercise attenuates chronic morphine-induced anxiogenesis and memory impairment but not reductions in hippocampal BDNF in female rats.

PubMed

Ghodrati-Jaldbakhan, Shahrbanoo; Ahmadalipour, Ali; Rashidy-Pour, Ali; Vafaei, Abbas Ali; Miladi-Gorji, Hossein; Alizadeh, Maryam

2017-05-15

Previous studies from our laboratory have shown that treadmill exercise alleviates the deficits in cognitive functions and anxiety behaviors induced by chronic exposure to morphine in male rats. In this study, we investigated the effects of low and high intensities of treadmill exercise on spatial memory, anxiety-like behaviors, and biochemical changes in the hippocampus and serum of morphine-treated female rats. The adult virgin female rats were injected with bi-daily doses (10mg/kg, at 12h intervals) of morphine over a period of 10days. Following these injections, the rats were exercised under low or high intensities for 30min per session on five days a week for four weeks. After exercise training, object location memory, anxiety profile, hippocampal BDNF, and serum corticosterone and BDNF were examined. Morphine-treated animals exhibited increased anxiety levels, impaired object location memory, and reduced hippocampal BDNF. Exercise alleviated these impairing effects on anxiety profile and memory but not hippocampal BDNF. The high-intensity exercise even further reduced the hippocampal BDNF. Additionally, both exercise regimens in the morphine group and the high exercise in the saline group reduced serum BDNF. Finally, the high-intensity exercise enhanced corticosterone serum. These findings indicate that the negative cognitive and behavioral effects of chronic exposure to morphine could be relieved by forced exercise in female rats. However, the exercise intensity is an important factor to be considered during exercise training. Finally, the correlation between changes of brain and serum BDNF and cognitive functions following morphine exposure needs further research. Copyright © 2017 Elsevier B.V. All rights reserved.

Parameter estimation and order selection for an empirical model of VO2 on-kinetics.

PubMed

Alata, O; Bernard, O

2007-04-27

In humans, VO2 on-kinetics are noisy numerical signals that reflect the pulmonary oxygen exchange kinetics at the onset of exercise. They are empirically modelled as a sum of an offset and delayed exponentials. The number of delayed exponentials; i.e. the order of the model, is commonly supposed to be 1 for low-intensity exercises and 2 for high-intensity exercises. As no ground truth has ever been provided to validate these postulates, physiologists still need statistical methods to verify their hypothesis about the number of exponentials of the VO2 on-kinetics especially in the case of high-intensity exercises. Our objectives are first to develop accurate methods for estimating the parameters of the model at a fixed order, and then, to propose statistical tests for selecting the appropriate order. In this paper, we provide, on simulated Data, performances of Simulated Annealing for estimating model parameters and performances of Information Criteria for selecting the order. These simulated Data are generated with both single-exponential and double-exponential models, and noised by white and Gaussian noise. The performances are given at various Signal to Noise Ratio (SNR). Considering parameter estimation, results show that the confidences of estimated parameters are improved by increasing the SNR of the response to be fitted. Considering model selection, results show that Information Criteria are adapted statistical criteria to select the number of exponentials.

High-Intensity Locomotor Exercise Increases Brain-Derived Neurotrophic Factor in Individuals with Incomplete Spinal Cord Injury

PubMed Central

Leech, Kristan A.

2017-01-01

Abstract High-intensity locomotor exercise is suggested to contribute to improved recovery of locomotor function after neurological injury. This may be secondary to exercise-intensity–dependent increases in neurotrophin expression demonstrated previously in control subjects. However, rigorous examination of intensity-dependent changes in neurotrophin levels is lacking in individuals with motor incomplete spinal cord injury (SCI). Therefore, the primary aim of this study was to evaluate the effect of locomotor exercise intensity on peripheral levels of brain-derived neurotrophic factor (BDNF) in individuals with incomplete SCI. We also explored the impact of the Val66Met single-nucleotide polymorphism (SNP) on the BDNF gene on intensity-dependent changes. Serum concentrations of BDNF and insulin-like growth factor-1 (IGF-1), as well as measures of cardiorespiratory dynamics, were evaluated across different levels of exercise intensity achieved during a graded-intensity, locomotor exercise paradigm in 11 individuals with incomplete SCI. Our results demonstrate a significant increase in serum BDNF at high, as compared to moderate, exercise intensities (p = 0.01) and 15 and 30 min post-exercise (p < 0.01 for both), with comparison to changes at low intensity approaching significance (p = 0.05). Serum IGF-1 demonstrated no intensity-dependent changes. Significant correlations were observed between changes in BDNF and specific indicators of exercise intensity (e.g., rating of perceived exertion; R = 0.43; p = 0.02). Additionally, the data suggest that Val66Met SNP carriers may not exhibit intensity-dependent changes in serum BDNF concentration. Given the known role of BDNF in experience-dependent neuroplasticity, these preliminary results suggest that exercise intensity modulates serum BDNF concentrations and may be an important parameter of physical rehabilitation interventions after neurological injury. PMID:27526567

Interleukin-6 and associated cytokine responses to an acute bout of high-intensity interval exercise: the effect of exercise intensity and volume.

PubMed

Cullen, Tom; Thomas, Andrew W; Webb, Richard; Hughes, Michael G

2016-08-01

Acute increases in interleukin (IL)-6 following prolonged exercise are associated with the induction of a transient anti-inflammatory state (e.g., increases in IL-10) that is partly responsible for the health benefits of regular exercise. The purposes of this study were to investigate the IL-6-related inflammatory response to high-intensity interval exercise (HIIE) and to determine the impact of exercise intensity and volume on this response. Ten participants (5 males and 5 females) completed 3 exercise bouts of contrasting intensity and volume (LOW, MOD, and HIGH). The HIGH protocol was based upon standard HIIE protocols, while the MOD and LOW protocols were designed to enable a comparison of exercise intensity and volume with a fixed duration. Inflammatory cytokine concentrations were measured in plasma (IL-6, IL-10) and also determined the level of gene expression (IL-6, IL-10, and IL-4R) in peripheral blood. The plasma IL-6 response to exercise (reported as fold changes) was significantly greater in HIGH (2.70 ± 1.51) than LOW (1.40 ± 0.32) (P = 0.04) and was also positively correlated to the mean exercise oxygen uptake (r = 0.54, P < 0.01). However, there was no change in anti-inflammatory IL-10 or IL-4R responses in plasma or at the level of gene expression. HIIE caused a significant increase in IL-6 and was greater than that seen in low-intensity exercise of the same duration. The increases in IL-6 were relatively small in magnitude, and appear to have been insufficient to induce the acute systemic anti-inflammatory effects, which are evident following longer duration exercise.

The effect of physical exercise on salivary secretion of MUC5B, amylase and lysozyme.

PubMed

Ligtenberg, Antoon J M; Brand, Henk S; van den Keijbus, Petra A M; Veerman, Enno C I

2015-11-01

Saliva secretion is regulated by the autonomic nervous system. Parasympathic stimuli increase the secretion of water and mucin MUC5B, whereas sympathetic stimuli such as physical exercise increase the secretion of amylase and other proteins. In the present study we investigated the effect of physical exercise, as a sympathetic stimulus, on salivary flow rate and output of MUC5B, amylase, lysozyme and total protein. Unstimulated whole saliva was collected before exercise (1), after 10 min exercise with moderate intensity by running with a heart rate around 130 beats per minute (2), followed by 10 min exercise with high intensity by running to exhaustion (3) and after 30 min recovery (4). Salivary flow rate, protein and MUC5B concentration, and amylase and lysozyme activity were determined. Saliva protein composition was analysed using SDS-PAGE and immunoblotting. Salivary flow rate, protein and lysozyme secretion increased after exercise with moderate intensity and increased further after exercise with high intensity (p<0.01). Amylase and MUC5B increased after exercise with moderate intensity (p<0.0001), but did not differ significantly between moderate and high exercise intensity. SDS-PAGE analysis and immunoblotting showed that, especially after exercise with high intensity, the concentrations of several other salivary proteins, including MUC7, albumin, and extra-parotid glycoprotein, also increased. Exercise may not only lead to the anticipated increase in amylase and protein secretion, but also to an increase in salivary flow rate and MUC5B secretion. Copyright © 2015 Elsevier Ltd. All rights reserved.

Usefulness of a Perceived Exertion Scale for Monitoring Exercise Intensity in Adults with Intellectual Disabilities

ERIC Educational Resources Information Center

Stanish, Heidi I.; Aucoin, Michael

2007-01-01

In order to gain physical fitness and health, exercise must be performed at a sufficient level of intensity. Exercise intensity can be monitored with rated perceived exertion (RPE) scales to promote safe and effective programming. The usefulness of the Children's OMNI Scale as a subjective measure of intensity for adults with intellectual…

Influence of Prior Intense Exercise and Cold Water Immersion in Recovery for Performance and Physiological Response during Subsequent Exercise

PubMed Central

Christensen, Peter M.; Bangsbo, Jens

2016-01-01

Athletes in intense endurance sports (e.g., 4000-m track cycling) often perform maximally (~4 min) twice a day due to qualifying and finals being placed on the same day. The purpose of the present study was to evaluate repeated performance on the same day in a competitive setting (part A) and the influence from prior intense exercise on subsequent performance and physiological response to moderate and maximal exercise with and without the use of cold water immersion (CWI) in recovery (part B). In part A, performance times during eight World championships for male track cyclists were extracted from the qualifying and final races in 4000-m individual pursuit. In part B, twelve trained cyclists with an average (±SD) ⩒O2-peak of 67 ± 5 mL/min/kg performed a protocol mimicking a qualifying race (QUAL) followed 3 h later by a performance test (PT) with each exercise period encompassing intense exercise for ~4 min preceded by an identical warm-up period in both a control setting (CON) and using cold water immersion in recovery (CWI; 15 min at 15°C). Performance was lowered (P < 0.001) from qualification to finals (259 ± 3 vs. 261 ± 3 s) for the track cyclists during World championships in part A. In part B, mean power in PT was not different in CWI relative to CON (406 ± 43 vs. 405 ± 38 W). Peak ⩒O2 (5.04 ± 0.50 vs. 5.00 ± 0.49 L/min) and blood lactate (13 ± 3 vs. 14 ± 3 mmol/L) did not differ between QUAL and PT and cycling economy and potassium handling was not impaired by prior intense exercise. In conclusion, performance is reduced with repeated maximal exercise in world-class track cyclists during 4000-m individual pursuit lasting ~4 min, however prior intense exercise do not appear to impair peak ⩒O2, peak lactate, cycling economy, or potassium handling in trained cyclists and CWI in recovery does not improve subsequent performance. PMID:27445857

Metformin improves performance in high-intensity exercise, but not anaerobic capacity in healthy male subjects.

PubMed

Learsi, S K; Bastos-Silva, V J; Lima-Silva, A E; Bertuzzi, R; De Araujo, G G

2015-10-01

The aim of this study was to determine the ergogenic effects of metformin in high-intensity exercise, as well as its effects on anaerobic capacity, in healthy and physically active men. Ten subjects (mean (± standard deviation) maximal oxygen uptake (V˙O2max ) 38.6 ± 4.5 mL/kg per min) performed the following tests in a cycle ergometer: (i) an incremental test; (ii) six submaximal constant workload tests at 40%-90% (V˙O2max ); and (iii) two supramaximal tests (110% (V˙O2max ). Metformin (500 mg) or placebo was ingested 60 min before the supramaximal test. There were no significant differences between the placebo and metformin groups in terms of maximum accumulated oxygen deficit (2.8 ± 0.6 vs 3.0 ± 0.8 L, respectively; P = 0.08), lactate concentrations (7.8 ± 2.6 vs 7.5 ± 3.0 mmol/L, respectively; P = 0.75) or O2 consumed in either the last 30 s of exercise (40.4 ± 4.4 vs 39.9 ± 4.0 mL/kg per min, respectively; P = 0.35) or the first 110 s of exercise (29.0 ± 2.5 vs 29.5 ± 3.0 mL/kg per min, respectively; P = 0.42). Time to exhaustion was significantly higher after metformin than placebo ingestion (191 ± 33 vs 167 ± 32 s, respectively; P = 0.001). The fast component of V˙O2 recovery was higher in the metformin than placebo group (12.71 vs 12.18 mL/kg per min, respectively; P = 0.025). Metformin improved performance and anaerobic alactic contribution during high-intensity exercise, but had no effect on overall anaerobic capacity in healthy subjects. © 2015 Wiley Publishing Asia Pty Ltd.

High-Intensity Intermittent Training Positively Affects Aerobic and Anaerobic Performance in Judo Athletes Independently of Exercise Mode

PubMed Central

Franchini, Emerson; Julio, Ursula F.; Panissa, Valéria L. G.; Lira, Fábio S.; Gerosa-Neto, José; Branco, Braulio H. M.

2016-01-01

Purpose: The present study investigated the effects of high-intensity intermittent training (HIIT) on lower- and upper-body graded exercise and high-intensity intermittent exercise (HIIE, four Wingate bouts) performance, and on physiological and muscle damage markers responses in judo athletes. Methods: Thirty-five subjects were randomly allocated to a control group (n = 8) or to one of the following HIIT groups (n = 9 for each) and tested pre- and post-four weeks (2 training d·wk−1): (1) lower-body cycle-ergometer; (2) upper-body cycle-ergometer; (3) uchi-komi (judo technique entrance). All HIIT were constituted by two blocks of 10 sets of 20 s of all out effort interspersed by 10 s set intervals and 5-min between blocks. Results: For the upper-body group there was an increase in maximal aerobic power in graded upper-body exercise test (12.3%). The lower-body group increased power at onset blood lactate in graded upper-body exercise test (22.1%). The uchi-komi group increased peak power in upper- (16.7%) and lower-body (8.5%), while the lower-body group increased lower-body mean power (14.2%) during the HIIE. There was a decrease in the delta blood lactate for the uchi-komi training group and in the third and fourth bouts for the upper-body training group. Training induced testosterone-cortisol ratio increased in the lower-body HIIE for the lower-body (14.9%) and uchi-komi (61.4%) training groups. Conclusion: Thus, short-duration low-volume HIIT added to regular judo training was able to increase upper-body aerobic power, lower- and upper-body HIIE performance. PMID:27445856

A single bout of high-intensity aerobic exercise facilitates response to paired associative stimulation and promotes sequence-specific implicit motor learning

PubMed Central

Mang, Cameron S.; Snow, Nicholas J.; Campbell, Kristin L.; Ross, Colin J. D.

2014-01-01

The objectives of the present study were to evaluate the impact of a single bout of high-intensity aerobic exercise on 1) long-term potentiation (LTP)-like neuroplasticity via response to paired associative stimulation (PAS) and 2) the temporal and spatial components of sequence-specific implicit motor learning. Additionally, relationships between exercise-induced increases in systemic brain-derived neurotrophic factor (BDNF) and response to PAS and motor learning were evaluated. Sixteen young healthy participants completed six experimental sessions, including the following: 1) rest followed by PAS; 2) aerobic exercise followed by PAS; 3) rest followed by practice of a continuous tracking (CT) task and 4) a no-exercise 24-h retention test; and 5) aerobic exercise followed by CT task practice and 6) a no-exercise 24-h retention test. The CT task included an embedded repeated sequence allowing for evaluation of sequence-specific implicit learning. Slope of motor-evoked potential recruitment curves generated with transcranial magnetic stimulation showed larger increases when PAS was preceded by aerobic exercise (59.8% increase) compared with rest (14.2% increase, P = 0.02). Time lag of CT task performance on the repeated sequence improved under the aerobic exercise condition from early (−100.8 ms) to late practice (−75.2 ms, P < 0.001) and was maintained at retention (−79.2 ms, P = 0.004) but did not change under the rest condition (P > 0.16). Systemic BDNF increased on average by 3.4-fold following aerobic exercise (P = 0.003), but the changes did not relate to neurophysiological or behavioral measures (P > 0.42). These results indicate that a single bout of high-intensity aerobic exercise can prime LTP-like neuroplasticity and promote sequence-specific implicit motor learning. PMID:25257866

Kinetic Analysis of Horizontal Plyometric Exercise Intensity.

PubMed

Kossow, Andrew J; Ebben, William P

2018-05-01

Kossow, AJ, DeChiara, TG, Neahous, SM, and Ebben, WP. Kinetic analysis of horizontal plyometric exercise intensity. J Strength Cond Res 32(5): 1222-1229, 2018-Plyometric exercises are frequently performed as part of a strength and conditioning program. Most studies assessed the kinetics of plyometric exercises primarily performed in the vertical plane. The purpose of this study was to evaluate the multiplanar kinetic characteristics of a variety of plyometric exercises, which have a significant horizontal component. This study also sought to assess sex differences in the intensity progression of these exercises. Ten men and 10 women served as subjects. The subjects performed a variety of plyometric exercises including the double-leg hop, standing long jump, single-leg standing long jump, bounding, skipping, power skipping, cone hops, and 45.72-cm hurdle hops. Subjects also performed the countermovement jump for comparison. All plyometric exercises were evaluated using a force platform. Dependent variables included the landing rate of force development and landing ground reaction forces for each exercise in the vertical, frontal, and sagittal planes. A 2-way mixed analysis of variance with repeated-measures for plyometric exercise type demonstrated main effects for exercise type for all dependent variables (p ≤ 0.001). There was no significant interaction between plyometric exercise type and sex for any of the variable assessed. Bonferroni-adjusted pairwise comparisons identified a number of differences between the plyometric exercises for the dependent variables assessed (p ≤ 0.05). These findings should be used to guide practitioners in the progression of plyometric exercise intensity, and thus program design, for those who require significant horizontal power in their sport.

Effects of high-intensity interval exercise versus continuous moderate-intensity exercise on postprandial glycemic control assessed by continuous glucose monitoring in obese adults.

PubMed

Little, Jonathan P; Jung, Mary E; Wright, Amy E; Wright, Wendi; Manders, Ralph J F

2014-07-01

The purpose of this study was to examine the impact of acute high-intensity interval training (HIIT) compared with continuous moderate-intensity (CMI) exercise on postprandial hyperglycemia in overweight or obese adults. Ten inactive, overweight or obese adults (41 ± 11 yrs, BMI = 36 ± 7 kg/m(2)) performed an acute bout of HIIT (10 × 1 min at approximately 90% peak heart rate (HRpeak) with 1-min recovery periods) or matched work CMI (30 min at approximately 65% HRpeak) in a randomized, counterbalanced fashion. Exercise was performed 2 h after breakfast, and glucose control was assessed by continuous glucose monitoring under standardized dietary conditions over 24 h. Postprandial glucose (PPG) responses to lunch, dinner, and the following day's breakfast were analyzed and compared with a no-exercise control day. Exercise did not affect the PPG responses to lunch, but performing both HIIT and CMI in the morning significantly reduced the PPG incremental area under the curve (AUC) following dinner when compared with control (HIIT = 110 ± 35, CMI = 125 ± 34, control = 162 ± 46 mmol/L × 2 h, p < 0.05). The PPG AUC (HIIT = 125 ± 53, CMI = 186 ± 55, control = 194 ± 96 mmol/L × 2 h) and the PPG spike (HIIT = Δ2.1 ± 0.9, CMI = Δ3.0 ± 0.9, control = Δ3.0 ± 1.5 mmol/l) following breakfast on the following day were significantly lower following HIIT compared with both CMI and control (p < 0.05). Absolute AUC and absolute glucose spikes were not different between HIIT, CMI, or control for any meal (p > 0.05 for all). We conclude that a single session of HIIT has greater and more lasting effects on reducing incremental PPG when compared with CMI.

High Intensity Exercise Countermeasures does not Prevent Orthostatic Intolerance Following Prolonged Bed Rest

NASA Technical Reports Server (NTRS)

Platts, Steven H.; Stenger, Michael B.; Ploutz-Snyder, Lori L.; Lee, Stuart M. C.

2014-01-01

Approximately 20% of Space Shuttle astronauts became presyncopal during operational stand and 80deg head-up tilt tests, and the prevalence of orthostatic intolerance increases after longer missions. Greater than 60% of the US astronauts participating in Mir and early International Space Station missions experienced presyncope during post-flight tilt tests, perhaps related to limitations of the exercise hardware that prevented high intensity exercise training until later ISS missions. The objective of this study was to determine whether an intense resistive and aerobic exercise countermeasure program designed to prevent cardiovascular and musculoskeletal deconditioning during 70 d of bed rest (BR), a space flight analog, would protect against post-BR orthostatic intolerance. METHODS Twenty-six subjects were randomly assigned to one of three groups: non-exercise controls (n=11) or one of two exercise groups (ExA, n=8; ExB, n=7). Both ExA and ExB groups performed the same resistive and aerobic exercise countermeasures during BR, but one exercise group received testosterone supplementation while the other received a placebo during BR in a double-blinded fashion. On 3 d/wk, subjects performed lower body resistive exercise and 30 min of continuous aerobic exercise (=75% max heart rate). On the other 3 d/wk, subjects performed only highintensity, interval-style aerobic exercise. Orthostatic intolerance was assessed using a 15-min 80? head-up tilt test performed 2 d (BR-2) before and on the last day of BR (BR70). Plasma volume was measured using carbon monoxide rebreathing on BR-3 and before rising on the first recovery day (BR+0). The code for the exercise groups has not been broken, and results are reported here without group identification. RESULTS Only one subject became presyncopal during tilt testing on BR-2, but 7 of 11 (63%) controls, 3 of 8 (38%) ExA, and 4 of 7 (57%) ExB subjects were presyncopal on BR70. Survival analysis of post-BR tilt tests revealed no differences (p=0.77) between groups. Plasma volume (absolute or relative to body mass index) decreased (p<0.001) from pre to post-BR, with no differences between groups. CONCLUSIONS These preliminary results corroborate previous reports that the performance of a vigorous exercise countermeasure protocol during BR, even with testosterone supplementation, does not protect against orthostatic intolerance or plasma volume loss. Preventing post-BR orthostatic intolerance may require additional countermeasures, such as orthostatic stress during BR or end-of-BR fluid infusion.

Individual preferences for physical exercise as secondary prevention for non-specific low back pain: A discrete choice experiment

PubMed Central

Hagberg, Jan; Axén, Iben; Kwak, Lydia; Lohela-Karlsson, Malin; Skillgate, Eva; Dahlgren, Gunilla; Jensen, Irene

2017-01-01

Background Exercise is effective in improving non-specific low back pain (LBP). Certain components of physical exercise, such as the type, intensity and frequency of exercise, are likely to influence participation among working adults with non-specific LBP, but the value and relative importance of these components remain unknown. The study’s aim was to examine such specific components and their influence on individual preferences for exercise for secondary prevention of non-specific LBP among working adults. Methods In a discrete choice experiment, working individuals with non-specific LBP answered a web-based questionnaire. Each respondent was given ten pairs of hypothetical exercise programs and asked to choose one option from each pair. The choices comprised six attributes of exercise (i.e., type of training, design, intensity, frequency, proximity and incentives), each with either three or four levels. A conditional logit regression that reflected the random utility model was used to analyze the responses. Results The final study population consisted of 112 participants. The participants’ preferred exercise option was aerobic (i.e., cardiovascular) rather than strength training, group exercise with trainer supervision, rather than individual or unsupervised exercise. They also preferred high intensity exercise performed at least once or twice per week. The most popular types of incentive were exercise during working hours and a wellness allowance rather than coupons for sports goods. The results show that the relative value of some attribute levels differed between young adults (age ≤ 44 years) and older adults (age ≥ 45 years) in terms of the level of trainer supervision required, exercise intensity, travel time to exercise location and financial incentives. For active study participants, exercise frequency (i.e., twice per week, 1.15; CI: 0.25; 2.06) influenced choice of exercise. For individuals with more than one child, travel time (i.e., 20 minutes, -0.55; CI: 0.65; 3.26) was also an influential attribute for choice of exercise, showing that people with children at home preferred to exercise close to home. Conclusions This study adds to our knowledge about what types of exercise working adults with back pain are most likely to participate in. The exercise should be a cardiovascular type of training carried out in a group with trainer supervision. It should also be of high intensity and preferably performed twice per week during working hours. Coupons for sports goods do not appear to motivate physical activity among workers with LBP. The findings of the study could have a substantial impact on the planning and development of exercise provision and promotion strategies to improve non-specific LBP. Providers and employers may be able to improve participation in exercise programs for adults with non-specific LBP by focusing on the exercise components which are the most attractive. This in turn would improve satisfaction and adherence to exercise interventions aimed at preventing recurrent non-specific LBP. PMID:29244841

Individual preferences for physical exercise as secondary prevention for non-specific low back pain: A discrete choice experiment.

PubMed

Aboagye, Emmanuel; Hagberg, Jan; Axén, Iben; Kwak, Lydia; Lohela-Karlsson, Malin; Skillgate, Eva; Dahlgren, Gunilla; Jensen, Irene

2017-01-01

Exercise is effective in improving non-specific low back pain (LBP). Certain components of physical exercise, such as the type, intensity and frequency of exercise, are likely to influence participation among working adults with non-specific LBP, but the value and relative importance of these components remain unknown. The study's aim was to examine such specific components and their influence on individual preferences for exercise for secondary prevention of non-specific LBP among working adults. In a discrete choice experiment, working individuals with non-specific LBP answered a web-based questionnaire. Each respondent was given ten pairs of hypothetical exercise programs and asked to choose one option from each pair. The choices comprised six attributes of exercise (i.e., type of training, design, intensity, frequency, proximity and incentives), each with either three or four levels. A conditional logit regression that reflected the random utility model was used to analyze the responses. The final study population consisted of 112 participants. The participants' preferred exercise option was aerobic (i.e., cardiovascular) rather than strength training, group exercise with trainer supervision, rather than individual or unsupervised exercise. They also preferred high intensity exercise performed at least once or twice per week. The most popular types of incentive were exercise during working hours and a wellness allowance rather than coupons for sports goods. The results show that the relative value of some attribute levels differed between young adults (age ≤ 44 years) and older adults (age ≥ 45 years) in terms of the level of trainer supervision required, exercise intensity, travel time to exercise location and financial incentives. For active study participants, exercise frequency (i.e., twice per week, 1.15; CI: 0.25; 2.06) influenced choice of exercise. For individuals with more than one child, travel time (i.e., 20 minutes, -0.55; CI: 0.65; 3.26) was also an influential attribute for choice of exercise, showing that people with children at home preferred to exercise close to home. This study adds to our knowledge about what types of exercise working adults with back pain are most likely to participate in. The exercise should be a cardiovascular type of training carried out in a group with trainer supervision. It should also be of high intensity and preferably performed twice per week during working hours. Coupons for sports goods do not appear to motivate physical activity among workers with LBP. The findings of the study could have a substantial impact on the planning and development of exercise provision and promotion strategies to improve non-specific LBP. Providers and employers may be able to improve participation in exercise programs for adults with non-specific LBP by focusing on the exercise components which are the most attractive. This in turn would improve satisfaction and adherence to exercise interventions aimed at preventing recurrent non-specific LBP.

Temporal characteristics of exercise-induced diaphragmatic fatigue.

PubMed

Archiza, Bruno; Welch, Joseph F; Geary, Caitlin M; Allen, Grayson P; Borghi-Silva, Audrey; Sheel, A William

2018-04-01

There is evidence suggesting diaphragmatic fatigue (DF) occurs relatively early during high-intensity exercise; however, studies investigating the temporal characteristics of exercise-induced DF are limited by incongruent methodology. Eight healthy adult males (25 ± 5 yr) performed a maximal incremental exercise test on a cycle ergometer on day 1. A constant-load time-to-exhaustion (TTE) exercise test was conducted on day 2 at 60% delta between the calculated gas exchange threshold and peak work rate. Two additional constant-load exercise tests were performed at the same intensity on days 3 and 4 in a random order to either 50 or 75% TTE. DF was assessed on days 2, 3, and 4 by measuring transdiaphragmatic twitch pressure (P di,tw ) in response to cervical magnetic stimulation. DF was present after 75 and 100% TTE (≥20% decrease in P di,tw ). The magnitude of fatigue was 15.5 ± 5.7%, 23.6 ± 6.4%, and 35.0 ± 12.1% at 50, 75, and 100% TTE, respectively. Significant differences were found between 100 to 75 and 50% TTE (both P < 0.01), and 75 to 50% TTE ( P < 0.01). There was a significant relationship between the magnitude of fatigue and cumulative diaphragm force output ( r = 0.785; P < 0.001). Ventilation, the mechanical work of breathing (WOB), and pressure-time products were not different between trials ( P > 0.05). Our data indicate that exercise-induced DF presents a relatively late onset and is proportional to the cumulative WOB; thus the ability of the diaphragm to generate pressure progressively declines throughout exercise. NEW & NOTEWORTHY The notion that diaphragmatic fatigue (DF) occurs relatively early during exercise is equivocal. Our results indicate that DF occurs during high-intensity endurance exercise in healthy men and its magnitude is strongly related to the amount of pressure and work generated by respiratory muscles. Thus we conclude that the work of breathing is the major determinant of exercise-induced DF.

High-Intensity Interval Exercises' Acute Impact on Heart Rate Variability: Comparison Between Whole-Body and Cycle Ergometer Protocols.

PubMed

Schaun, Gustavo Z; Del Vecchio, Fabrício B

2018-01-01

Schaun, GZ and Del Vecchio, FB. High-intensity interval exercises' acute impact on heart rate variability: comparison between whole-body and cycle ergometer protocols. J Strength Cond Res 32(1): 223-229, 2018-Study aimed to compare the effects of 2 high-intensity interval training (HIIT) protocols on heart rate variability. Twelve young adult males (23.3 ± 3.9 years, 177.8 ± 7.4 cm, 76.9 ± 12.9 kg) volunteered to participate. In a randomized cross-over design, subjects performed 2 HIIT protocols, 1 on a cycle ergometer (Tabata protocol [TBT]; eight 20-second bouts at 170% Pmax interspersed by 10-second rest) and another with whole-body calisthenic exercises (McRae protocol; eight 20-second all-out intervals interspersed by 10-second rest). Heart rate variability outcomes in the time, frequency, and nonlinear domains were assessed on 3 moments: (a) presession; (b) immediately postsession; and (c) 24 hours postsession. Results revealed that RRmean, Ln rMSSD, Ln high frequency (HF), and Ln low frequency (LF) were significantly reduced immediately postsession (p ≤ 0.001) and returned to baseline 24 h after both protocols. In addition, LF/HF ratio was reduced 24 h postsession (p ≤ 0.01) and SD2 was significantly lower immediately postsession only in TBT. Our main finding was that responses from heart rate autonomic control were similar in both protocols, despite different modes of exercise performed. Specifically, exercises resulted in a high parasympathetic inhibition immediately after session with subsequent recovery within 1 day. These results suggest that subjects were already recovered the day after and can help coaches to better program training sessions with such protocols.

How should COPD patients exercise during respiratory rehabilitation? Comparison of exercise modalities and intensities to treat skeletal muscle dysfunction

PubMed Central

Puhan, M; Schunemann, H; Frey, M; Scharplatz, M; Bachmann, L

2005-01-01

Background: Physical exercise is an important component of respiratory rehabilitation because it reverses skeletal muscle dysfunction, a clinically important manifestation of COPD associated with reduced health-related quality of life (HRQL) and survival. However, there is controversy regarding the components of the optimal exercise protocol. A study was undertaken to systematically evaluate and summarise randomised controlled trials (RCTs) comparing different exercise protocols for COPD patients. Methods: Six electronic databases, congress proceedings and bibliographies of included studies were searched without imposing language restrictions. Two reviewers independently screened all records and extracted data on study samples, interventions and methodological characteristics of included studies. Results: The methodological quality of the 15 included RCTs was low to moderate. Strength exercise led to larger improvements of HRQL than endurance exercise (weighted mean difference for Chronic Respiratory Questionnaire 0.27, 95% CI 0.02 to 0.52). Interval exercise seems to be of similar effectiveness as continuous exercise, but there are few data on clinically relevant outcomes. One small RCT which included patients with mild COPD compared the effect of high and low intensity exercise (at 80% and 40% of the maximum exercise capacity, respectively) and found larger physiological training effects from high intensity exercise. Conclusions: Strength exercise should be routinely incorporated in respiratory rehabilitation. There is insufficient evidence to recommend high intensity exercise for COPD patients and investigators should conduct larger high quality trials to evaluate exercise intensities in patients with moderate to severe COPD. PMID:15860711

Relationship between the number of repetitions and selected percentages of one repetition maximum in free weight exercises in trained and untrained men.

PubMed

Shimano, Tomoko; Kraemer, William J; Spiering, Barry A; Volek, Jeff S; Hatfield, Disa L; Silvestre, Ricardo; Vingren, Jakob L; Fragala, Maren S; Maresh, Carl M; Fleck, Steven J; Newton, Robert U; Spreuwenberg, Luuk P B; Häkkinen, Keijo

2006-11-01

Resistance exercise intensity is commonly prescribed as a percent of 1 repetition maximum (1RM). However, the relationship between percent 1RM and the number of repetitions allowed remains poorly studied, especially using free weight exercises. The purpose of this study was to determine the maximal number of repetitions that trained (T) and untrained (UT) men can perform during free weight exercises at various percentages of 1RM. Eight T and 8 UT men were tested for 1RM strength. Then, subjects performed 1 set to failure at 60, 80, and 90% of 1RM in the back squat, bench press, and arm curl in a randomized, balanced design. There was a significant (p < 0.05) intensity x exercise interaction. More repetitions were performed during the back squat than the bench press or arm curl at 60% 1RM for T and UT. At 80 and 90% 1RM, there were significant differences between the back squat and other exercises; however, differences were much less pronounced. No differences in number of repetitions performed at a given exercise intensity were noted between T and UT (except during bench press at 90% 1RM). In conclusion, the number of repetitions performed at a given percent of 1RM is influenced by the amount of muscle mass used during the exercise, as more repetitions can be performed during the back squat than either the bench press or arm curl. Training status of the individual has a minimal impact on the number of repetitions performed at relative exercise intensity.

Functional and Neuromuscular Changes in the Hamstrings After Drop Jumps and Leg Curls

PubMed Central

Sarabon, Nejc; Panjan, Andrej; Rosker, Jernej; Fonda, Borut

2013-01-01

The purpose of this study was to use a holistic approach to investigate changes in jumping performance, kinaesthesia, static balance, isometric strength and fast stepping on spot during a 5-day recovery period, following an acute bout of damaging exercise consisted of drop jumps and leg curls, where specific emphasis was given on the hamstring muscles. Eleven young healthy subjects completed a series of highly intensive damaging exercises for their hamstring muscles. Prior to the exercise, and during the 5-day recovery period, the subjects were tested for biochemical markers (creatine kinase, aspartate aminotransferase, and lactate dehydrogenase), perceived pain sensation, physical performance (squat jump, counter movement jump, maximal frequency leg stamping, maximal isometric torque production and maximally explosive isometric torque production), kinaesthesia (active torque tracking) and static balance. We observed significant decreases in maximal isometric knee flexion torque production, the rate of torque production, and majority of the parameters for vertical jump performance. No alterations were found in kinaesthesia, static balance and fast stepping on spot. The highest drop in performance and increase in perceived pain sensation generally occurred 24 or 48 hours after the exercise. Damaging exercise substantially alters the neuromuscular functions of the hamstring muscles, which is specifically relevant for sports and rehabilitation experts, as the hamstrings are often stretched to significant lengths, in particular when the knee is extended and hip flexed. These findings are practically important for recovery after high-intensity trainings for hamstring muscles. Key Points Hamstring function is significantly reduced following specifically damaging exercise. It fully recovers 120 hours after the exercise. Prevention of exercise-induced muscle damage is cruicial for maintaining normal training regime. PMID:24149148

High-Intensity Training Improves Exercise Performance in Elite Women Volleyball Players During a Competitive Season.

PubMed

Purkhús, Elisabeth; Krustrup, Peter; Mohr, Magni

2016-11-01

Purkhús, E, Krustrup, P, and Mohr, M. High-intensity training improves exercise performance in elite women volleyball players during a competitive season. J Strength Cond Res 30(11): 3066-3072, 2016-Elite women volleyball players (n = 25; mean ± SD: age, 19 ± 5 years; height, 171 ± 7 cm; weight, 63 ± 10 kg) volunteered to participate in the study. They were randomized into a high-intensity training (HIT; n = 13) group and a control (CON; n = 12) group. In addition to the normal team training and games, HIT performed 6-10 × 30-seconds all-out running intervals separated by 3-minute recovery periods 3 times per week during a 4-week in-season period whereas CON only completed the team training sessions and games. Preintervention and postintervention, all players completed the arrowhead agility test (AAT), a repeated sprint test (RST; 5 × 30 meters separated by 25 seconds of recovery), and the Yo-Yo Intermittent Recovery level 2 test (Yo-Yo IR2) followed by a-10 minute rest period and the Yo-Yo IR1 test. Mean running distance during HIT in week 1 was 152 ± 4 m and increased (p ≤ 0.05) by 4.6% (159 ± 3 m) in week 4. The AAT performance improved (p ≤ 0.05) by 2.3% (18.87 ± 0.97-18.44 ± 1.06 seconds) and RST by 4.3% postintervention in the HIT group only. Baseline RST fatigue index was 7.0 ± 2.9 and 6.2 ± 5.0% in HIT and CON, respectively, but was lowered (p ≤ 0.05) to 2.7 ± 3.0% posttraining in HIT and remained unaltered in CON (5.5 ± 5.0%). In HIT, Yo-Yo IR2 and Yo-Yo IR1 performance improved by 12.6 and 18.3% postintervention, respectively, with greater (p ≤ 0.05) Yo-yo IR1 change scores than in CON. In conclusion, additional high-intensity in-season training performed as interval running improved agility, repeated sprint ability, and high-intensity intermittent exercise performance in elite women volleyball players.

Keto analogue and amino acid supplementation and its effects on ammonemia and performance under thermoneutral conditions.

PubMed

Camerino, Saulo Rodrigo Alves e Silva; Lima, Rafaela Carvalho Pereira; França, Thássia Casado Lima; Herculano, Edla de Azevedo; Rodrigues, Daniela Souza Araújo; Gouveia, Marcos Guilherme de Sousa; Cameron, L C; Prado, Eduardo Seixas

2016-02-01

Alterations of cerebral function, fatigue and disturbance in cognitive-motor performance can be caused by hyperammonemia and/or hot environmental conditions during exercise. Exercise-induced hyperammonemia can be reduced through supplementation with either amino acids or combined keto analogues and amino acids (KAAA) to improve exercise tolerance. In the present study, we evaluated KAAA supplementation on ammonia metabolism and cognitive-motor performance after high-intensity exercise under a low heat stress environment. Sixteen male cyclists received a ketogenic diet for 2 d and were divided into two groups, KAAA (KEx) or placebo (CEx) supplementation. The athletes performed a 2 h cycling session followed by a maximum test (MAX), and blood samples were obtained at rest and during exercise. Cognitive-motor tasks were performed before and after the protocol, and the exhaustion time was used to evaluate physical performance. The hydration status was also evaluated. The CEx group showed a significant increase (∼ 70%) in ammonia concentration at MAX, which did not change in the KEx group. The non-supplemented group showed a significant increase in uremia. Both the groups had a significant increase in blood urate concentrations at 120 min, and an early significant increase from 120 min was observed in the CEx group. There was no change in the glucose concentrations of the two groups. A significant increase in lactate was observed at the MAX moment in both groups. There was no significant difference in the exhaustion times between the groups. No changes were observed in the cognitive-motor tasks after the protocol. We suggest that KAAA supplementation decreases ammonia concentration during high-intensity exercise but does not affect physical or cognitive-motor performances under a low heat stress environment.

High-intensity intermittent exercise training with chlorella intake accelerates exercise performance and muscle glycolytic and oxidative capacity in rats.

PubMed

Horii, Naoki; Hasegawa, Natsuki; Fujie, Shumpei; Uchida, Masataka; Miyamoto-Mikami, Eri; Hashimoto, Takeshi; Tabata, Izumi; Iemitsu, Motoyuki

2017-04-01

The purpose of this study was to investigate the effect of chronic chlorella intake alone or in combination with high-intensity intermittent exercise (HIIE) training on exercise performance and muscle glycolytic and oxidative metabolism in rats. Forty male Sprague-Dawley rats were randomly assigned to the four groups: sedentary control, chlorella intake (0.5% chlorella powder in normal feed), HIIE training, and combination of HIIE training and chlorella intake for 6 wk ( n = 10 each group). HIIE training comprised 14 repeats of a 20-s swimming session with a 10-s pause between sessions, while bearing a weight equivalent to 16% of body weight, 4 days/week. Exercise performance was tested after the interventions by measuring the maximal number of HIIE sessions that could be completed. Chlorella intake and HIIE training significantly increased the maximal number of HIIE sessions and enhanced the expression of monocarboxylate transporter (MCT)1, MCT4, and peroxisome proliferator-activated receptor γ coactivator-1α concomitantly with the activities of lactate dehydrogenase (LDH), phosphofructokinase, citrate synthase (CS), and cytochrome- c oxidase (COX) in the red region of the gastrocnemius muscle. Furthermore, the combination further augmented the increased exercise performance and the enhanced expressions and activities. By contrast, in the white region of the muscle, MCT1 expression and LDH, CS, and COX activities did not change. These results showed that compared with only chlorella intake and only HIIE training, chlorella intake combined with HIIE training has a more pronounced effect on exercise performance and muscle glycolytic and oxidative metabolism, in particular, lactate metabolism. Copyright © 2017 the American Physiological Society.

Reliability of a Novel High Intensity One Leg Dynamic Exercise Protocol to Measure Muscle Endurance

PubMed Central

Lepers, Romuald; Marcora, Samuele M.

2016-01-01

We recently developed a high intensity one leg dynamic exercise (OLDE) protocol to measure muscle endurance and investigate the central and peripheral mechanisms of muscle fatigue. The aims of the present study were to establish the reliability of this novel protocol and describe the isokinetic muscle fatigue induced by high intensity OLDE and its recovery. Eight subjects performed the OLDE protocol (time to exhaustion test of the right leg at 85% of peak power output) three times over a week period. Isokinetic maximal voluntary contraction torque at 60 (MVC60), 100 (MVC100) and 140 (MVC140) deg/s was measured pre-exercise, shortly after exhaustion (13 ± 4 s), 20 s (P20) and 40 s (P40) post-exercise. Electromyographic (EMG) signal was analyzed via the root mean square (RMS) for all three superficial knee extensors. Mean time to exhaustion was 5.96 ± 1.40 min, coefficient of variation was 8.42 ± 6.24%, typical error of measurement was 0.30 min and intraclass correlation was 0.795. MVC torque decreased shortly after exhaustion for all angular velocities (all P < 0.001). MVC60 and MVC100 recovered between P20 (P < 0.05) and exhaustion and then plateaued. MVC140 recovered only at P40 (P < 0.05). High intensity OLDE did not alter maximal EMG RMS of the three superficial knee extensors during MVC. The results of this study demonstrate that this novel high intensity OLDE protocol could be reliably used to measure muscle endurance, and that muscle fatigue induced by high intensity OLDE should be examined within ~ 30 s following exhaustion. PMID:27706196

Submaximal exercise intensity modulates acute post-exercise heart rate variability.

PubMed

Michael, Scott; Jay, Ollie; Halaki, Mark; Graham, Kenneth; Davis, Glen M

2016-04-01

This study investigated whether short-term heart rate variability (HRV) can be used to differentiate between the immediate recovery periods following three different intensities of preceding exercise. 12 males cycled for 8 min at three intensities: LOW (40-45 %), MOD (75-80 %) and HIGH (90-95 %) of heart rate (HR) reserve. HRV was assessed during exercise and throughout 10-min seated recovery. 1-min HR recovery was reduced following greater exercise intensities when expressed as R-R interval (RRI, ms) (p < 0.001), but not b min(-1) (p = 0.217). During exercise, the natural logarithm of root mean square of successive differences (Ln-RMSSD) was higher during LOW (1.66 ± 0.47 ms) relative to MOD (1.14 ± 0.32 ms) and HIGH (1.30 ± 0.25 ms) (p ≤ 0.037). Similar results were observed for high-frequency spectra (Ln-HF-LOW: 2.9 ± 1.0; MOD: 1.6 ± 0.6; HIGH: 1.6 ± 0.3 ms(2), p < 0.001). By 1-min recovery, higher preceding exercise intensities resulted in lower HRV amongst all three intensities for Ln-RMSSD (LOW: 3.45 ± 0.58; MOD: 2.34 ± 0.81; HIGH: 1.66 ± 0.78 ms, p < 0.001) and Ln-HF (LOW: 6.0 ± 1.0; MOD: 4.3 ± 1.4; HIGH: 2.8 ± 1.4 ms(2), p < 0.001). Similarly, by 1-min recovery 'HR-corrected' HRV (Ln-RMSSD: RRI × 10(3)) was different amongst all three intensities (LOW: 3.64 ± 0.49; MOD: 2.90 ± 0.65; HIGH: 2.40 ± 0.67, p < 0.001). These differences were maintained throughout 10-min recovery (p ≤ 0.027). Preceding exercise intensity has a graded effect on recovery HRV measures reflecting cardiac vagal activity, even after correcting for the underlying HR. The immediate recovery following exercise is a potentially useful period to investigate autonomic activity, as multiple levels of autonomic activity can be clearly differentiated between using HRV. When investigating post-exercise HRV it is critical to account for the relative exercise intensity.

Patients Awaiting Surgical Repair for Large Abdominal Aortic Aneurysms Can Exercise at Moderate to Hard Intensities with a Low Risk of Adverse Events

PubMed Central

Weston, Matthew; Batterham, Alan M.; Tew, Garry A.; Kothmann, Elke; Kerr, Karen; Nawaz, Shah; Yates, David; Danjoux, Gerard

2017-01-01

Purpose: Intervention fidelity refers to the extent an experimental manipulation has been implemented as intended. Our aim was to evaluate the fidelity of high-intensity interval training (HIT) in patients awaiting repair of large abdominal aortic aneurysms. Methods: Following a baseline cardiopulmonary exercise test, 27 participants performed a hospital-based, supervised HIT intervention in the 4 weeks preceding surgery. The intervention was performed thrice weekly on a cycle ergometer and involved either 8 × 2-min intervals, each interspersed by 2-min recovery periods, or 4 × 4-min intervals interspersed with 4-min recovery periods. When surgery was delayed, participants undertook one maintenance HIT session per week until surgery. Session one power output was set to baseline anaerobic threshold power output and then increased on subsequent sessions until ratings of perceived exertion (RPE; Borg CR-10) for the legs (RPE-L) and sense of breathlessness/ chest (RPE-C) were hard (5) to very hard (7) at the end of each interval. For safety, power output was maintained or reduced if systolic blood pressure exceeded 180 mm Hg or heart rate exceeded 95% of maximum. Results: Overall session attendance across the 4-week HIT intervention was 74%. Seventeen participants met our compliance criteria of ≥75% of intervention sessions and all maintenance sessions. When compared to non-compliance, compliant participants had higher fitness, performed more HIT sessions and were able to exercise at higher exercise intensities with a lower proportion of exercise safety breaches. In the 17 compliant participants, the proportion of repetitions meeting the HIT criterion was 30% (RPE-L) and 16% (RPE-C). Mean repetition intensity was 4.1 ± 2.0 Arbitrary Units [AU] (RPE-L) and 3.5 ± 1.9 AU (RPE-C) with a within-subject variability of ±1.4 AU and ±1.6 AU, respectively. We observed higher RPE scores (~0.5 AU) following 2-min intervals when compared to 4-min intervals and exercise power output increased 23% across the 4-week HIT intervention. One participant experienced an adverse event but were still able to complete their remaining exercise sessions. Conclusions: Despite an inconsistent and lower than prescribed intensity, it is possible to exercise this high-risk patient population at moderate to hard intensities with a low risk of adverse events. Clinical Trial Registration: http://www.isrctn.com/, registration number ISRCTN09433624. PMID:28119627

Performance in sports--With specific emphasis on the effect of intensified training.

PubMed

Bangsbo, J

2015-12-01

Performance in most sports is determined by the athlete's technical, tactical, physiological and psychological/social characteristics. In the present article, the physical aspect will be evaluated with a focus on what limits performance, and how training can be conducted to improve performance. Specifically how intensified training, i.e., increasing the amount of aerobic high-intensity and speed endurance training, affects physiological adaptations and performance of trained subjects. Periods of speed endurance training do improve performance in events lasting 30 s-4 min, and when combined with aerobic high-intensity sessions, also performance during longer events. Athletes in team sports involving intense exercise actions and endurance aspects, such as soccer and basketball, can also benefit from intensified training. Speed endurance training does reduce energy expenditure and increase expression of muscle Na(+), K(+) pump α subunits, which may preserve muscle cell excitability and delay fatigue development during intense exercise. When various types of training are conducted in the same period (concurrent training), as done in a number of sports, one type of training may blunt the effect of other types of training. It is not, however, clear how various training modalities are affecting each other, and this issue should be addressed in future studies. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Plasma Irisin Modestly Increases during Moderate and High-Intensity Afternoon Exercise in Obese Females

PubMed Central

Winn, Nathan C.; Grunewald, Zachary I.; Liu, Ying; Heden, Timothy D.; Nyhoff, Lauren M.; Kanaley, Jill A.

2017-01-01

Background and Purpose Irisin is an exercise-responsive myokine that has been proposed to exert anti-obesity benefits; yet its response during exercise in obese women is not described. This study characterized plasma irisin levels during a single bout of afternoon isocaloric-exercise of different intensities (moderate- vs high-intensity) in obese females. Methods Eleven obese females participated in 3 randomized study days beginning at 1600h: 1) no exercise (NoEx), 2) moderate exercise (ModEx; 55%VO2max) and 3) high intensity interval exercise (IntEx; 4 min (80%VO2max)/3 min (50% VO2max). Frequent blood samples were analyzed for glucose and lactate (whole-blood), and insulin, c-peptide, glucagon, and irisin (plasma) throughout 190 min of testing. Results Plasma irisin increased above baseline during ModEx and IntEx (P<0.05), but not NoEx (P>0.05). Peak irisin levels during ModEx and IntEx exercise were 11.9± 3.4% and 12.3 ± 4.1% relative to baseline (P<0.05), respectively, with no differences between exercise intensities (P>0.05). Irisin levels remained elevated above resting for 125 minutes post-exercise during ModEx, whereas levels returned to baseline within 15 minutes post-exercise during IntEx. Similarly, no associations were found between plasma irisin levels and circulating lactate, glucose, insulin, c-peptide, or glucagon among study days (P>0.05). However, there was an inverse association between basal irisin and lean mass (r = -0.70, P = 0.01). Conclusion A single bout of moderate and high intensity afternoon exercise induces modest increases in circulating irisin concentrations during exercise; however the regulation post-exercise appears to be dimorphic between exercise intensity in obese females. Future studies are needed to compare morning and afternoon exercise on irisin secretion. PMID:28125733

Exercise and health-related quality of life during the first year following acute stroke. A randomized controlled trial.

PubMed

Langhammer, Birgitta; Stanghelle, Johan K; Lindmark, Birgitta

2008-02-01

To evaluate the impact of two different physiotherapy exercise regimes in patients after acute stroke on health-related quality of life (HRQoL) and to investigate how the degree of motor and balance function, gait capacity, activities of daily living and instrumental activities of daily living influenced HRQoL. A longitudinal randomized controlled stratified trial of two interventions: the intensive exercise groups with scheduled intensive training during four periods of the first year after stroke and the regular exercise group with self-initiated training. There was a tendency of better HRQoL in the regular exercise group on NHP total score (p = 0.05). Patients with low scores in activities of daily living, balance and motor function and inability to perform 6-minute walk test on admission, scored lower on self-perceived health than patients with high scores and ability to perform the walking test. At 1 year post-stroke, total scores on NHP were moderately associated with motor function (r = -0.63), balance (r = -0.56), gait (r = -0.57), activities of daily living (r = -0.57) and instrumental activities of daily living (r = -0.49-0.58). The physical mobility sub-scale of NHP had the strongest association ranging from r = -0.47-0.82. The regular exercise group with self-initiated training seemed to enhance HRQoL more than the intensive exercise group with scheduled intensive training. The degree of motor function, balance, walking capacity and independence in activities of daily living is of importance for perceived HRQoL.

Safety of American Heart Association-recommended minimum exercise for desmosomal mutation carriers.

PubMed

Sawant, Abhishek C; Te Riele, Anneline S J M; Tichnell, Crystal; Murray, Brittney; Bhonsale, Aditya; Tandri, Harikrishna; Judge, Daniel P; Calkins, Hugh; James, Cynthia A

2016-01-01

Endurance exercise is associated with adverse outcomes in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). Exercise recommendations for family members remain undetermined. The purposes of this study were to determine if (1) endurance exercise (Bethesda class C) and exercise intensity (metabolic equivalent hours per year [MET-Hr/year]) increase the likelihood of fulfilling 2010 Task Force Criteria and ventricular arrhythmias/implantable cardioverter-defibrillator shock (ventricular tachycardia/ventricular fibrillation [VT/VF]), and (2) exercise restriction to the American Heart Association (AHA)-recommended minimum for healthy adults is associated with favorable outcomes of at-risk family members. Twenty-eight family members of 10 probands inheriting a PKP2 mutation were interviewed about exercise from age 10. Exercise threshold to maintain overall health was based on the 2007 AHA guidelines of a minimum 390 to 650 MET-Hr/year. After adjustment for age, sex, and family membership, both participation in endurance athletics (odds ratio [OR] 7.4, P = .03) and higher-intensity exercise (OR = 4.2, P = .004) were associated with diagnosis (n = 13). Endurance athletes were also significantly more likely to develop VT/VF (n = 6, P = .02). Family members who restricted exercise at or below the upper bound of the AHA goal (≤650 MET-Hr/year) were significantly less likely to be diagnosed (OR = 0.07, P = .002) and had no VT/VF. At diagnosis and first VT/VF, family members had accumulated 2.8-fold (P = .002) and 3.5-fold (P = .03), respectively, greater MET-Hr exercise than the AHA-recommended minimum. Those who developed VT/VF had performed particularly high-intensity exercise in adolescence compared to unaffected family members (age 10-14: P = .04; age 14-19: P = .02). The results of this study suggest restricting unaffected desmosomal mutation carriers from endurance and high-intensity athletics but potentially not from AHA-recommended minimum levels of exercise for healthy adults. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Effect of aerobic exercise on physical performance in patients with Alzheimer's disease.

PubMed

Sobol, Nanna Aue; Hoffmann, Kristine; Frederiksen, Kristian Steen; Vogel, Asmus; Vestergaard, Karsten; Brændgaard, Hans; Gottrup, Hanne; Lolk, Annette; Wermuth, Lene; Jakobsen, Søren; Laugesen, Lars; Gergelyffy, Robert; Høgh, Peter; Bjerregaard, Eva; Siersma, Volkert; Andersen, Birgitte Bo; Johannsen, Peter; Waldemar, Gunhild; Hasselbalch, Steen Gregers; Beyer, Nina

2016-12-01

Knowledge about the feasibility and effects of exercise programs to persons with Alzheimer's disease is lacking. This study investigated the effect of aerobic exercise on physical performance in community-dwelling persons with mild Alzheimer's disease. The single blinded multi-center RCT (ADEX) included 200 patients, median age 71 yrs (50-89). The intervention group received supervised moderate-to-high intensity aerobic exercise 1 hour × 3/week for 16 weeks. Assessments included cardiorespiratory fitness, single-task physical performance, dual-task performance and exercise self-efficacy. Significant between-group differences in change from baseline (mean [95%CI]) favored the intervention group for cardiorespiratory fitness (4.0 [2.3-5.8] ml/kg/min, P <0.0001) and exercise self-efficacy (1.7 [0.5-2.8] points, P =0.004). Furthermore, an exercise attendance of ≥66.6% resulted in significant positive effects on single-task physical performance and dual-task performance. Aerobic exercise has the potential to improve cardiorespiratory fitness, single-task physical performance, dual-task performance and exercise self-efficacy in community-dwelling patients with mild Alzheimer's disease. Copyright © 2016 the Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

The effects of creatine pyruvate and creatine citrate on performance during high intensity exercise

PubMed Central

Jäger, Ralf; Metzger, Jan; Lautmann, Karin; Shushakov, Vladimir; Purpura, Martin; Geiss, Kurt-Reiner; Maassen, Norbert

2008-01-01

Background A double-blind, placebo-controlled, randomized study was performed to evaluate the effect of oral creatine pyruvate (Cr-Pyr) and creatine citrate (Cr-Cit) supplementation on exercise performance in healthy young athletes. Methods Performance during intermittent handgrip exercise of maximal intensity was evaluated before (pretest) and after (posttest) 28 days of Cr-Pyr (5 g/d, n = 16), Cr-Cit (5 g/d, n = 16) or placebo (pla, 5 g/d, n = 17) intake. Subjects performed ten 15-sec exercise intervals, each followed by 45 sec rest periods. Results Cr-Pyr (p < 0.001) and Cr-Cit (p < 0.01) significantly increased mean power over all intervals. Cr-Cit increased force during the first and second interval (p < 0.01) compared to placebo. The effect of Cr-Cit on force decreased over time and the improvement was not significant at the sixth and ninth interval, whereas Cr-Pyr significantly increased force during all intervals (p < 0.001). Cr-Pyr (p < 0.001) and Cr-Cit (p < 0.01) resulted in an increase in contraction velocity, whereas only Cr-Pyr intake significantly (p < 0.01) increased relaxation velocity. Oxygen consumption measured during rest periods significantly increased with Cr-Pyr (p < 0.05), whereas Cr-Cit and placebo intake did not result in significant improvements. Conclusion It is concluded that four weeks of Cr-Pyr and Cr-Cit intake significantly improves performance during intermittent handgrip exercise of maximal intensity and that Cr-Pyr might benefit endurance, due to enhanced activity of the aerobic metabolism. PMID:18269769

Responses of blood pressure and lactate levels to various aquatic exercise movements in postmenopausal women.

PubMed

Chien, K-Y; Chen, W-C; Kan, N-W; Hsu, M-C; Lee, S-L

2015-12-01

Middle-aged and elderly women represent the main attending group in head-out aquatic exercise (HOAE). Blood pressure (BP) significantly increases both during water immersion and aquatic walking. Based on risk concerns, it is important to evaluate BP responses in postmenopausal women doing HOAE. The aim of this study was to determine BP, lactate levels, and rating of perceived exertion (RPE) changes associated with performing 3 different movements at 3 levels of exercise intensity in water. Twelve postmenopausal women (59.9±0.6 years old) participated in 3 aquatic trials involving running (RU), rocking (RO), and scissor kicks (SK) on separate days. Systolic BP, mean arterial pressure (MAP), lactate levels, RPE, and motion cadence were measured at rest; upon reaching 50%, 65%, and 80% of heart rate reserve for 6 minutes; and 10 and 30 minutes after exercise. Under similar RPE responses at 3 levels of intensity, SK resulted in higher systolic BP, MAP, and lactate levels than RO at 10 minutes after exercise (P<0.05) and the lowest motion cadence (P<0.05). RO resulted in the lowest MAP and diastolic BP responses during exercise (P<0.05). RU resulted in lower responses of lactate levels at high exercise intensity (P<0.05). RO resulted in lower diastolic BP and MAP responses compared with RU and SK during exercise. These findings suggest that RO movement in aquatic exercises is more suitable for people at high risk for cardiovascular disease.

The Effects of Pre-Exercise Ginger Supplementation on Muscle Damage and Delayed Onset Muscle Soreness.

PubMed

Matsumura, Melissa D; Zavorsky, Gerald S; Smoliga, James M

2015-06-01

Ginger possesses analgesic and pharmacological properties mimicking non-steroidal antiinflammatory drugs. We aimed to determine if ginger supplementation is efficacious for attenuating muscle damage and delayed onset muscle soreness (DOMS) following high-intensity resistance exercise. Following a 5-day supplementation period of placebo or 4 g ginger (randomized groups), 20 non-weight trained participants performed a high-intensity elbow flexor eccentric exercise protocol to induce muscle damage. Markers associated with muscle damage and DOMS were repeatedly measured before supplementation and for 4 days following the exercise protocol. Repeated measures analysis of variance revealed one repetition maximum lift decreased significantly 24 h post-exercise in both groups (p < 0.005), improved 48 h post-exercise only in the ginger group (p = 0.002), and improved at 72 (p = 0.021) and 96 h (p = 0.044) only in the placebo group. Blood creatine kinase significantly increased for both groups (p = 0.015) but continued to increase only in the ginger group 72 (p = 0.006) and 96 h (p = 0.027) post-exercise. Visual analog scale of pain was significantly elevated following eccentric exercise (p < 0.001) and was not influenced by ginger. In conclusion, 4 g of ginger supplementation may be used to accelerate recovery of muscle strength following intense exercise but does not influence indicators of muscle damage or DOMS. Copyright © 2015 John Wiley & Sons, Ltd.

Development of low-volume, high-intensity, aerobic-type interval training for elderly Japanese men: a feasibility study.

PubMed

Osuka, Yosuke; Matsubara, Muneaki; Hamasaki, Ai; Hiramatsu, Yuji; Ohshima, Hiroshi; Tanaka, Kiyoji

2017-01-01

The purposes of this study were to identify 1) the feasibility of a novel exercise protocol (elderly Japanese male version of high-intensity interval aerobic training: EJ-HIAT) and 2) its preliminary data (%V̇O 2peak , rating of perceived exertion) in comparison with traditional moderate-intensity continuous aerobic training (MICT). Twenty-one sedentary elderly men, aged 60-69 years, performed two exercise protocols: EJ-HIAT, consisting of 3 sets of 2-3-min cycling at 75-85%V̇O 2peak with 1-2-min active rests at 50%V̇O 2peak between sets, and MICT, consisting of 40-min cycling at 65%V̇O 2peak . The completion rate, defined as the rate of participants who 1) did not demand withdrawal, 2) were not interrupted by the tester, and 3) did not change the workload during either exercise protocol, of EJ-HIAT was similar to that of MICT (EJ-HIAT: 100%, MICT: 95.2%). Maximal perceived exertion ratings assessed by Borg scale were also similar between EJ-HIAT and MICT. However, objectively measured maximal intensity assessed by %V̇O 2peak was higher for EJ-HIAT than for MICT (EJ-HIAT: 86.0 ± 5.6%, MICT: 67.1 ± 6.4%). These results suggested that EJ-HIAT has good feasibility and perceived exertion similar to MICT despite having higher objectively measured intensity than MICT. An intervention aimed as identifying the effects of EJ-HIAT on exercise tolerance should be performed in the future. UMIN000021185 (February 26, 2016).

Effects of high-intensity swimming training on the bones of ovariectomized rats

PubMed Central

Oh, Taewoong; Tanaka, Sakura; Naka, Tatsuki; Igawa, Shoji

2016-01-01

[Purpose] This study was performed to assess the effects of high-intensity intermittent swimming training(HIT) on bone in ovariectomized rats. [Methods] Six-week-old female Sprague-Dawley rats were randomly assigned to either sham operation or bilateral ovariectomy. After surgery, they were divided into the following four groups: 1) sham-operated sedentary (S), 2) sham-operated exercise training (SE), 3) OVX sedentary (O), 4) OVX exercise training (OE) 5) OVX given 17β-estradiol (OE2) and 6) OVX exercise training and given 17β-estradiol (OEE). SE, OE and OEE rats were used extremely high-intensity swim exercise. The rats repeated fourteen 20-s swimming bouts with a weight equivalent to 14, 15, and 16% of body weight for the first 5, the next 9, and the last 5 days, respectively. Between exercise bouts, a 10-s pause was allowed. HIT was originally designed as an exercise method; a method that very quickly induces an increase in the maximum oxygen intake (Tabata I et al., 1996). OEE and OE2 rats were subcutaneously injected ethanol with 25μg/kg body weight 17β-estradiol 3 times per week. [Results] Bone strength, bone mineral density and trabecular bone parameters were measured after a 8-weeks experimental period. Bone strength was significantly higher in the SE, OE, OE2 and OEE group compared with the O group. BV/TV was significant increase in the SE, OE groups compared with the O group. BMD showed no difference in the OE group compared with the O group. [Conclusion] This study demonstrate some beneficial effects of postmenopausal osteoporosis of high-intensity intermittent swimming training on bone structure and strength. PMID:27757386

Effects of high-intensity swimming training on the bones of ovariectomized rats.

PubMed

Oh, Taewoong; Tanaka, Sakura; Naka, Tatsuki; Igawa, Shoji

2016-09-01

This study was performed to assess the effects of high-intensity intermittent swimming training(HIT) on bone in ovariectomized rats. Six-week-old female Sprague-Dawley rats were randomly assigned to either sham operation or bilateral ovariectomy. After surgery, they were divided into the following four groups: 1) sham-operated sedentary (S), 2) sham-operated exercise training (SE), 3) OVX sedentary (O), 4) OVX exercise training (OE) 5) OVX given 17β-estradiol (OE2) and 6) OVX exercise training and given 17β-estradiol (OEE). SE, OE and OEE rats were used extremely high-intensity swim exercise. The rats repeated fourteen 20-s swimming bouts with a weight equivalent to 14, 15, and 16% of body weight for the first 5, the next 9, and the last 5 days, respectively. Between exercise bouts, a 10-s pause was allowed. HIT was originally designed as an exercise method; a method that very quickly induces an increase in the maximum oxygen intake (Tabata I et al., 1996). OEE and OE2 rats were subcutaneously injected ethanol with 25μg/kg body weight 17β-estradiol 3 times per week. Bone strength, bone mineral density and trabecular bone parameters were measured after a 8-weeks experimental period. Bone strength was significantly higher in the SE, OE, OE2 and OEE group compared with the O group. BV/TV was significant increase in the SE, OE groups compared with the O group. BMD showed no difference in the OE group compared with the O group. This study demonstrate some beneficial effects of postmenopausal osteoporosis of high-intensity intermittent swimming training on bone structure and strength.

Novel, high-intensity exercise prescription improves muscle mass, mitochondrial function, and physical capacity in individuals with Parkinson's disease

PubMed Central

Kelly, Neil A.; Ford, Matthew P.; Standaert, David G.; Watts, Ray L.; Bickel, C. Scott; Moellering, Douglas R.; Tuggle, S. Craig; Williams, Jeri Y.; Lieb, Laura; Windham, Samuel T.

2014-01-01

We conducted, in persons with Parkinson's disease (PD), a thorough assessment of neuromotor function and performance in conjunction with phenotypic analyses of skeletal muscle tissue, and further tested the adaptability of PD muscle to high-intensity exercise training. Fifteen participants with PD (Hoehn and Yahr stage 2–3) completed 16 wk of high-intensity exercise training designed to simultaneously challenge strength, power, endurance, balance, and mobility function. Skeletal muscle adaptations (P < 0.05) to exercise training in PD included myofiber hypertrophy (type I: +14%, type II: +36%), shift to less fatigable myofiber type profile, and increased mitochondrial complex activity in both subsarcolemmal and intermyofibrillar fractions (I: +45–56%, IV: +39–54%). These adaptations were accompanied by a host of functional and clinical improvements (P < 0.05): total body strength (+30–56%); leg power (+42%); single leg balance (+34%); sit-to-stand motor unit activation requirement (−30%); 6-min walk (+43 m), Parkinson's Disease Quality of Life Scale (PDQ-39, −7.8pts); Unified Parkinson's Disease Rating Scale (UPDRS) total (−5.7 pts) and motor (−2.7 pts); and fatigue severity (−17%). Additionally, PD subjects in the pretraining state were compared with a group of matched, non-PD controls (CON; did not exercise). A combined assessment of muscle tissue phenotype and neuromuscular function revealed a higher distribution and larger cross-sectional area of type I myofibers and greater type II myofiber size heterogeneity in PD vs. CON (P < 0.05). In conclusion, persons with moderately advanced PD adapt to high-intensity exercise training with favorable changes in skeletal muscle at the cellular and subcellular levels that are associated with improvements in motor function, physical capacity, and fatigue perception. PMID:24408997

Can supine recovery mitigate the exercise intensity dependent attenuation of post-exercise heat loss responses?

PubMed

Kenny, Glen P; Gagnon, Daniel; Jay, Ollie; McInnis, Natalie H; Journeay, W Shane; Reardon, Francis D

2008-08-01

Cutaneous vascular conductance (CVC) and sweat rate are subject to non-thermal baroreflex-mediated attenuation post-exercise. Various recovery modalities have been effective in attenuating these decreases in CVC and sweat rate post-exercise. However, the interaction of recovery posture and preceding exercise intensity on post-exercise thermoregulation remains unresolved. We evaluated the combined effect of supine recovery and exercise intensity on post-exercise cardiovascular and thermal responses relative to an upright seated posture. Seven females performed 15 min of cycling ergometry at low- (LIE, 55% maximal oxygen consumption) or high-(HIE, 85% maximal oxygen consumption) intensity followed by 60 min of recovery in either an upright seated or supine posture. Esophageal temperature, CVC, sweat rate, cardiac output, stroke volume, heart rate, total peripheral resistance, and mean arterial pressure (MAP) were measured at baseline, at end-exercise, and at 2, 5, 12, 20, and every 10 min thereafter until the end of recovery. MAP and stroke volume were maintained during supine recovery to a greater extent relative to an upright seated recovery following HIE (p

Effect of water-based recovery on blood lactate removal after high-intensity exercise.

PubMed

Lucertini, Francesco; Gervasi, Marco; D'Amen, Giancarlo; Sisti, Davide; Rocchi, Marco Bruno Luigi; Stocchi, Vilberto; Benelli, Piero

2017-01-01

This study assessed the effectiveness of water immersion to the shoulders in enhancing blood lactate removal during active and passive recovery after short-duration high-intensity exercise. Seventeen cyclists underwent active water- and land-based recoveries and passive water and land-based recoveries. The recovery conditions lasted 31 minutes each and started after the identification of each cyclist's blood lactate accumulation peak, induced by a 30-second all-out sprint on a cycle ergometer. Active recoveries were performed on a cycle ergometer at 70% of the oxygen consumption corresponding to the lactate threshold (the control for the intensity was oxygen consumption), while passive recoveries were performed with subjects at rest and seated on the cycle ergometer. Blood lactate concentration was measured 8 times during each recovery condition and lactate clearance was modeled over a negative exponential function using non-linear regression. Actual active recovery intensity was compared to the target intensity (one sample t-test) and passive recovery intensities were compared between environments (paired sample t-tests). Non-linear regression parameters (coefficients of the exponential decay of lactate; predicted resting lactates; predicted delta decreases in lactate) were compared between environments (linear mixed model analyses for repeated measures) separately for the active and passive recovery modes. Active recovery intensities did not differ significantly from the target oxygen consumption, whereas passive recovery resulted in a slightly lower oxygen consumption when performed while immersed in water rather than on land. The exponential decay of blood lactate was not significantly different in water- or land-based recoveries in either active or passive recovery conditions. In conclusion, water immersion at 29°C would not appear to be an effective practice for improving post-exercise lactate removal in either the active or passive recovery modes.

Upper-extremity functional electric stimulation-assisted exercises on a workstation in the subacute phase of stroke recovery.

PubMed

Kowalczewski, Jan; Gritsenko, Valeriya; Ashworth, Nigel; Ellaway, Peter; Prochazka, Arthur

2007-07-01

To test the efficacy of functional electric stimulation (FES)-assisted exercise therapy (FES-ET) on a workstation in the subacute phase of recovery from a stroke. Single-blind, randomly controlled comparison of high- and low-intensity treatment. Laboratory in a rehabilitation hospital. Nineteen stroke survivors (10 men, 9 women; mean age +/- standard deviation, 60.6+/-5.8y), with upper-extremity hemiplegia (mean poststroke time, 48+/-17d). The main inclusion criteria were: stroke occurred within 3 months of onset of trial and resulted in severe upper-limb dysfunction, and FES produced adequate hand opening. An FES stimulator and an exercise workstation with instrumented objects were used by 2 groups to perform specific motor tasks with their affected upper extremity. Ten subjects in the high-intensity FES-ET group received FES-ET for 1 hour a day on 15 to 20 consecutive workdays. Nine subjects in the low-intensity FES-ET group received 15 minutes of sensory electric stimulation 4 days a week and on the fifth day they received 1 hour of FES-ET. Primary outcome measure included the Wolf Motor Function Test (WMFT). Secondary outcome measures included the Motor Activity Log (MAL), the upper-extremity portion of the Fugl-Meyer Assessment (FMA), and the combined kinematic score (CKS) derived from workstation measurements. The WMFT, MAL, and FMA were used to assess function in the absence of FES whereas CKS was used to evaluate function assisted by FES. Improvements in the WMFT and CKS were significantly greater in the high-intensity group (post-treatment effect size, .95) than the low-intensity group (post-treatment effect size, 1.3). The differences in MAL and FMA were not statistically significant. Subjects performing high-intensity FES-ET showed significantly greater improvements on the WMFT than those performing low-intensity FES-ET. However, this was not reflected in subjects' self-assessments (MAL) or in their FMA scores, so the clinical significance of the result is open to debate. The CKS data suggest that high-intensity FES-ET may be advantageous in neuroprosthetic applications.

Ingestion of High Molecular Weight Carbohydrate Enhances Subsequent Repeated Maximal Power: A Randomized Controlled Trial

PubMed Central

Oliver, Jonathan M.; Almada, Anthony L.; Van Eck, Leighsa E.; Shah, Meena; Mitchell, Joel B.; Jones, Margaret T.; Jagim, Andrew R.; Rowlands, David S.

2016-01-01

Athletes in sports demanding repeat maximal work outputs frequently train concurrently utilizing sequential bouts of intense endurance and resistance training sessions. On a daily basis, maximal work within subsequent bouts may be limited by muscle glycogen availability. Recently, the ingestion of a unique high molecular weight (HMW) carbohydrate was found to increase glycogen re-synthesis rate and enhance work output during subsequent endurance exercise, relative to low molecular weight (LMW) carbohydrate ingestion. The effect of the HMW carbohydrate, however, on the performance of intense resistance exercise following prolonged-intense endurance training is unknown. Sixteen resistance trained men (23±3 years; 176.7±9.8 cm; 88.2±8.6 kg) participated in a double-blind, placebo-controlled, randomized 3-way crossover design comprising a muscle-glycogen depleting cycling exercise followed by ingestion of placebo (PLA), or 1.2 g•kg•bw-1 of LMW or HMW carbohydrate solution (10%) with blood sampling for 2-h post-ingestion. Thereafter, participants performed 5 sets of 10 maximal explosive repetitions of back squat (75% of 1RM). Compared to PLA, ingestion of HMW (4.9%, 90%CI 3.8%, 5.9%) and LMW (1.9%, 90%CI 0.8%, 3.0%) carbohydrate solutions substantially increased power output during resistance exercise, with the 3.1% (90% CI 4.3, 2.0%) almost certain additional gain in power after HMW-LMW ingestion attributed to higher movement velocity after force kinematic analysis (HMW-LMW 2.5%, 90%CI 1.4, 3.7%). Both carbohydrate solutions increased post-exercise plasma glucose, glucoregulatory and gut hormones compared to PLA, but differences between carbohydrates were unclear; thus, the underlying mechanism remains to be elucidated. Ingestion of a HMW carbohydrate following prolonged intense endurance exercise provides superior benefits to movement velocity and power output during subsequent repeated maximal explosive resistance exercise. This study was registered with clinicaltrials.gov (NCT02778373). PMID:27636206

Ingestion of High Molecular Weight Carbohydrate Enhances Subsequent Repeated Maximal Power: A Randomized Controlled Trial.

PubMed

Oliver, Jonathan M; Almada, Anthony L; Van Eck, Leighsa E; Shah, Meena; Mitchell, Joel B; Jones, Margaret T; Jagim, Andrew R; Rowlands, David S

2016-01-01

Athletes in sports demanding repeat maximal work outputs frequently train concurrently utilizing sequential bouts of intense endurance and resistance training sessions. On a daily basis, maximal work within subsequent bouts may be limited by muscle glycogen availability. Recently, the ingestion of a unique high molecular weight (HMW) carbohydrate was found to increase glycogen re-synthesis rate and enhance work output during subsequent endurance exercise, relative to low molecular weight (LMW) carbohydrate ingestion. The effect of the HMW carbohydrate, however, on the performance of intense resistance exercise following prolonged-intense endurance training is unknown. Sixteen resistance trained men (23±3 years; 176.7±9.8 cm; 88.2±8.6 kg) participated in a double-blind, placebo-controlled, randomized 3-way crossover design comprising a muscle-glycogen depleting cycling exercise followed by ingestion of placebo (PLA), or 1.2 g•kg•bw-1 of LMW or HMW carbohydrate solution (10%) with blood sampling for 2-h post-ingestion. Thereafter, participants performed 5 sets of 10 maximal explosive repetitions of back squat (75% of 1RM). Compared to PLA, ingestion of HMW (4.9%, 90%CI 3.8%, 5.9%) and LMW (1.9%, 90%CI 0.8%, 3.0%) carbohydrate solutions substantially increased power output during resistance exercise, with the 3.1% (90% CI 4.3, 2.0%) almost certain additional gain in power after HMW-LMW ingestion attributed to higher movement velocity after force kinematic analysis (HMW-LMW 2.5%, 90%CI 1.4, 3.7%). Both carbohydrate solutions increased post-exercise plasma glucose, glucoregulatory and gut hormones compared to PLA, but differences between carbohydrates were unclear; thus, the underlying mechanism remains to be elucidated. Ingestion of a HMW carbohydrate following prolonged intense endurance exercise provides superior benefits to movement velocity and power output during subsequent repeated maximal explosive resistance exercise. This study was registered with clinicaltrials.gov (NCT02778373).

Skeletal muscle fatigue precedes the slow component of oxygen uptake kinetics during exercise in humans.

PubMed

Cannon, Daniel T; White, Ailish C; Andriano, Melina F; Kolkhorst, Fred W; Rossiter, Harry B

2011-02-01

The mechanisms determining exercise intolerance are poorly understood. A reduction in work efficiency in the form of an additional energy cost and oxygen requirement occurs during high-intensity exercise and contributes to exercise limitation. Muscle fatigue and subsequent recruitment of poorly efficient muscle fibres has been proposed to mediate this decline. These data demonstrate in humans, that muscle fatigue, generated in the initial minutes of exercise, is correlated with the increasing energy demands of high-intensity exercise. Surprisingly, however, while muscle fatigue reached a plateau, oxygen uptake continued to increase throughout 8 min of exercise. This suggests that additional recruitment of inefficient muscle fibres may not be the sole mechanism contributing to the decline in work efficiency during high-intensity exercise.

Role of fat metabolism in exercise.

PubMed

Askew, E W

1984-07-01

Fat and carbohydrate are the two major energy sources used during exercise. Either source can predominate, depending upon the duration and intensity of exercise, degree of prior physical conditioning, and the composition of the diet consumed in the days prior to a bout of exercise. Fatty acid oxidation can contribute 50 to 60 per cent of the energy expenditure during a bout of low intensity exercise of long duration. Strenuous submaximal exercise requiring 65 to 80 per cent of VO2 max will utilize less fat (10 to 45 per cent of the energy expended). Exercise training is accompanied by metabolic adaptations that occur in skeletal muscle and adipose tissue and that facilitate a greater delivery and oxidation of fatty acids during exercise. The trained state is characterized by an increased flux of fatty acids through smaller pools of adipose tissue energy. This is reflected by smaller, more metabolically active adipose cells in smaller adipose tissue depots. Peak blood concentrations of free fatty acids and ketone bodies are lower during and following exercise in trained individuals, probably due to increased capacity of the skeletal musculature to oxidize these energy sources. Trained individuals oxidize more fat and less carbohydrate than untrained subjects when performing submaximal work of the same absolute intensity. This increased capacity to utilize energy from fat conserves crucial muscle and liver glycogen stores and can contribute to increased endurance. Further benefits of the enhanced lipid metabolism accompanying chronic aerobic exercise training are decreased cardiac risk factors. Exercise training results in lower blood cholesterol and triglycerides and increased high density lipoprotein cholesterol. High-fat diets are not recommended because of their association with atherosclerotic heart disease. Recent evidence suggests that low-fat high-carbohydrate diets may increase blood triglycerides and reduce high density lipoproteins. This suggests that the chronic ingestion of diets that are extreme in their composition of either fat or carbohydrate should be approached with caution in health-conscious athletes, as well as in sedentary individuals.

Whole-Body Vibration Intensities in Chronic Stroke: A Randomized Controlled Trial.

PubMed

Liao, Lin-Rong; Ng, Gabriel Y F; Jones, Alice Y M; Huang, Mei-Zhen; Pang, Marco Y C

2016-07-01

A single-blinded randomized controlled study was conducted to investigate the effects of different whole-body vibration (WBV) intensities on body functions/structures, activity, and participation in individuals with stroke. Eighty-four individuals with chronic stroke (mean age = 61.2 yr, SD = 9.2) with mild to moderate motor impairment (Chedoke-McMaster Stroke Assessment lower limb motor score: median = 9 out of 14, interquartile range = 7-11.8) were randomly assigned to a low-intensity WBV, high-intensity WBV, or control group. The former two groups performed various leg exercises while receiving low-intensity and high-intensity WBV, respectively. Controls performed the same exercises without WBV. All individuals received 30 training sessions over an average period of 75.5 d (SD = 5.2). Outcome measurements included knee muscle strength (isokinetic dynamometry), knee and ankle joint spasticity (Modified Ashworth Scale), balance (Mini Balance Evaluation Systems Test), mobility (Timed-Up-and-Go test), walking endurance (6-Minute Walk Test), balance self-efficacy (Activities-specific Balance Confidence scale), participation in daily activities (Frenchay Activity Index), perceived environmental barriers to societal participation (Craig Hospital Inventory of Environmental Factors), and quality of life (Short-Form 12 Health Survey). Assessments were performed at baseline and postintervention. Intention-to-treat analysis revealed a significant time effect for muscle strength, Timed-Up-and-Go distance, and oxygen consumption rate achieved during the 6-Minute Walk Test, the Mini Balance Evaluation Systems Test, the Activities-specific Balance Confidence scale, and the Short-Form 12 Health Survey physical composite score domain (P < 0.05). However, the time-group interaction was not significant for any of the outcome measures (P > 0.05). The addition of the 30-session WBV paradigm to the leg exercise protocol was no more effective in enhancing body functions/structures, activity, and participation than leg exercises alone in chronic stroke patients with mild to moderate motor impairments.

Acute Effects of Carbohydrate Supplementation on Intermittent Sports Performance

PubMed Central

Baker, Lindsay B.; Rollo, Ian; Stein, Kimberly W.; Jeukendrup, Asker E.

2015-01-01

Intermittent sports (e.g., team sports) are diverse in their rules and regulations but similar in the pattern of play; that is, intermittent high-intensity movements and the execution of sport-specific skills over a prolonged period of time (~1–2 h). Performance during intermittent sports is dependent upon a combination of anaerobic and aerobic energy systems, both of which rely on muscle glycogen and/or blood glucose as an important substrate for energy production. The aims of this paper are to review: (1) potential biological mechanisms by which carbohydrate may impact intermittent sport performance; (2) the acute effects of carbohydrate ingestion on intermittent sport performance, including intermittent high-intensity exercise capacity, sprinting, jumping, skill, change of direction speed, and cognition; and (3) what recommendations can be derived for carbohydrate intake before/during exercise in intermittent sports based on the available evidence. The most researched intermittent sport is soccer but some sport-specific studies have also been conducted in other sports (e.g., rugby, field hockey, basketball, American football, and racquet sports). Carbohydrate ingestion before/during exercise has been shown in most studies to enhance intermittent high-intensity exercise capacity. However, studies have shown mixed results with regards to the acute effects of carbohydrate intake on sprinting, jumping, skill, change of direction speed, and cognition. In most of these studies the amount of carbohydrate consumed was ~30–60 g/h in the form of a 6%–7% carbohydrate solution comprised of sucrose, glucose, and/or maltodextrin. The magnitude of the impact that carbohydrate ingestion has on intermittent sport performance is likely dependent on the carbohydrate status of the individual; that is, carbohydrate ingestion has the greatest impact on performance under circumstances eliciting fatigue and/or hypoglycemia. Accordingly, carbohydrate ingestion before and during a game seems to have the greatest impact on intermittent sports performance towards the end of the game. PMID:26184303

Acute Effects of Carbohydrate Supplementation on Intermittent Sports Performance.

PubMed

Baker, Lindsay B; Rollo, Ian; Stein, Kimberly W; Jeukendrup, Asker E

2015-07-14

Intermittent sports (e.g., team sports) are diverse in their rules and regulations but similar in the pattern of play; that is, intermittent high-intensity movements and the execution of sport-specific skills over a prolonged period of time (~1-2 h). Performance during intermittent sports is dependent upon a combination of anaerobic and aerobic energy systems, both of which rely on muscle glycogen and/or blood glucose as an important substrate for energy production. The aims of this paper are to review: (1) potential biological mechanisms by which carbohydrate may impact intermittent sport performance; (2) the acute effects of carbohydrate ingestion on intermittent sport performance, including intermittent high-intensity exercise capacity, sprinting, jumping, skill, change of direction speed, and cognition; and (3) what recommendations can be derived for carbohydrate intake before/during exercise in intermittent sports based on the available evidence. The most researched intermittent sport is soccer but some sport-specific studies have also been conducted in other sports (e.g., rugby, field hockey, basketball, American football, and racquet sports). Carbohydrate ingestion before/during exercise has been shown in most studies to enhance intermittent high-intensity exercise capacity. However, studies have shown mixed results with regards to the acute effects of carbohydrate intake on sprinting, jumping, skill, change of direction speed, and cognition. In most of these studies the amount of carbohydrate consumed was ~30-60 g/h in the form of a 6%-7% carbohydrate solution comprised of sucrose, glucose, and/or maltodextrin. The magnitude of the impact that carbohydrate ingestion has on intermittent sport performance is likely dependent on the carbohydrate status of the individual; that is, carbohydrate ingestion has the greatest impact on performance under circumstances eliciting fatigue and/or hypoglycemia. Accordingly, carbohydrate ingestion before and during a game seems to have the greatest impact on intermittent sports performance towards the end of the game.

Fueling strategies to optimize performance: training high or training low?

PubMed

Burke, L M

2010-10-01

Availability of carbohydrate as a substrate for the muscle and central nervous system is critical for the performance of both intermittent high-intensity work and prolonged aerobic exercise. Therefore, strategies that promote carbohydrate availability, such as ingesting carbohydrate before, during and after exercise, are critical for the performance of many sports and a key component of current sports nutrition guidelines. Guidelines for daily carbohydrate intakes have evolved from the "one size fits all" recommendation for a high-carbohydrate diets to an individualized approach to fuel needs based on the athlete's body size and exercise program. More recently, it has been suggested that athletes should train with low carbohydrate stores but restore fuel availability for competition ("train low, compete high"), based on observations that the intracellular signaling pathways underpinning adaptations to training are enhanced when exercise is undertaken with low glycogen stores. The present literature is limited to studies of "twice a day" training (low glycogen for the second session) or withholding carbohydrate intake during training sessions. Despite increasing the muscle adaptive response and reducing the reliance on carbohydrate utilization during exercise, there is no clear evidence that these strategies enhance exercise performance. Further studies on dietary periodization strategies, especially those mimicking real-life athletic practices, are needed. © 2010 John Wiley & Sons A/S.

Repeated high-intensity interval exercise shortens the positive effect on executive function during post-exercise recovery in healthy young males.

PubMed

Tsukamoto, Hayato; Suga, Tadashi; Takenaka, Saki; Tanaka, Daichi; Takeuchi, Tatsuya; Hamaoka, Takafumi; Isaka, Tadao; Ogoh, Shigehiko; Hashimoto, Takeshi

2016-06-01

A single bout of aerobic exercise improves executive function (EF), but only for a short period. Compared with a single bout of aerobic exercise, we recently found that high-intensity interval exercise (HIIE) could maintain a longer improvement in EF. However, the mechanism underlying the effect of different exercise modes on the modifications of EF remains unclear. The purpose of the current investigation was to test our hypothesis that the amount of exercise-induced lactate production and its accumulation affects human brain function during and after exercise, thereby affecting post-exercise EF. Ten healthy male subjects performed cycle ergometer exercise. The HIIE protocol consisted of four 4-min bouts at 90% peak VO2 with a 3-min active recovery period at 60% peak VO2. The amount of lactate produced during exercise was manipulated by repeating the HIIE twice with a resting period of 60min between the 1st HIIE and 2nd HIIE. To evaluate EF, a color-word Stroop task was performed, and reverse-Stroop interference scores were obtained. EF immediately after the 1st HIIE was significantly improved compared to that before exercise, and the improved EF was sustained during 40min of the post-exercise recovery. However, for the 2nd HIIE, the improved EF was sustained for only 10min of the post-exercise recovery period, despite the performance of the same exercise. In addition, during and following HIIE, the glucose and lactate accumulation induced by the 2nd HIIE was significantly lower than that induced by the 1st HIIE. Furthermore, there was an inverse relationship between lactate and EF by plotting the changes in lactate levels against changes in EF from pre-exercise during the late phase of post-exercise recovery. These findings suggested the possibility that repeated bouts of HIIE, which decreases lactate accumulation, may dampen the positive effect of exercise on EF during the post-exercise recovery. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Exercise Intensity-Dependent Effects on Cognitive Control Function during and after Acute Treadmill Running in Young Healthy Adults

PubMed Central

Wohlwend, Martin; Olsen, Alexander; Håberg, Asta K.; Palmer, Helen S.

2017-01-01

The idea that physical activity differentially impacts upon performance of various cognitive tasks has recently gained increased interest. However, our current knowledge about how cognition is altered by acute physical activity is incomplete. To measure how different intensity levels of physical activity affect cognition during and after 1 bout of physical activity, 30 healthy, young participants were randomized to perform a not-X continuous performance test (CPT) during low (LI)- and moderate intensity (MI) running. The same participants were subsequently randomized to perform the not-X CPT post LI, MI, and high intensity (HI) running. In addition, exercise related mood changes were assessed through a self-report measure pre and post running at LI, MI, and HI. Results showed worsening of performance accuracy on the not-X CPT during one bout of moderate compared to low intensity running. Post running, there was a linear decrease in reaction time with increasing running intensity and no change in accuracy or mood. The decreased reaction times post HI running recovered back to baseline within 20 min. We conclude that accuracy is acutely deteriorated during the most straining physical activity while a transient intensity-dependent enhancement of cognitive control function is present following physical activity. PMID:28377735

The effect of 10 days of intermittent fasting on Wingate anaerobic power and prolonged high-intensity time-to-exhaustion cycling performance.

PubMed

Naharudin, Mohamed Nashrudin Bin; Yusof, Ashril

2018-06-01

Many physically active individuals have undertaken intermittent fasting to reduce their daily caloric intake. However, abstaining from meals for a specific length of time may lead to the acute disturbance of highly carbohydrate-dependent exercise performance. The purpose of this study was to observe the effect of 10 days of intermittent fasting on high-intensity type exercises, Wingate anaerobic (WT) and prolonged high-intensity time-to-exhaustion (HIT) cycling test. Twenty participants were randomised into an intermittent fasting (FAS) and a control group (CON). One day after baseline data collection on Day-0 where participants consumed their recommended daily caloric intake (FAS = 2500 ± 143 kcal day -1 ; CON = 2492 ± 20 kcal day -1 ) served over a course of five meals, the FAS group consumed only four meals where 40% was restricted by the omission of lunch (FAS = 1500 ± 55 kcal day -1 ). This diet was then continued for 10 days. Data on exercise performance and other dependent variables were collected on Day-2, -4, -6, -8 and -10. A reduction in WT power in the FAS group was observed on Day-2 (821.74 ± 66.07 W) compared to Day-0 (847.63 ± 95.94 W) with a moderate effect size (p < .05, ES = 0.4), while HIT time-to-exhaustion performance declined over the 10 days with a trend of recovery from a large to a minimum effect size (p < .05, ES = 0.8-0.3). Body weight and triglyceride were consistently reduced in the FAS group (p < .01). The present study suggests that intermittent fasting must exceed 10 days to ensure that high-intensity performance does not deteriorate because this length of time seems to be required for effective adaptation to the new dietary regimen.

A 10-s sprint performed prior to moderate-intensity exercise prevents early post-exercise fall in glycaemia in individuals with type 1 diabetes.

PubMed

Bussau, V A; Ferreira, L D; Jones, T W; Fournier, P A

2007-09-01

We investigated whether a 10-s maximal sprint effort performed immediately prior to moderate-intensity exercise provides another means to counter the rapid fall in glycaemia associated with moderate-intensity exercise in individuals with type 1 diabetes. Seven complication-free type 1 diabetic males (21.6 +/- 3.6 years; mean+/-SD) with HbA(1c) levels of 7.4 +/- 0.7% injected their normal morning insulin dose and ate their usual breakfast. When post-meal glycaemia fell to approximately 11 mmol/l, participants were asked to perform a 10-s all-out sprint (sprint trial) or to rest (control trial) immediately before cycling at 40% of peak rate of oxygen consumption for 20 min, with both trials conducted in a random counterbalanced order. Sprinting did not affect the rapid fall in glycaemia during the subsequent bout of moderate-intensity exercise (2.9 +/- 0.4 mmol/l in 20 min; p = 0.00; mean+/-SE). However, during the following 45 min of recovery, glycaemia in the control trial decreased by 1.23 +/- 0.60 mmol/l (p = 0.04) while remaining stable in the sprint trial, subsequently decreasing in this latter trial at a rate similar to that in the control trial. The large increase in noradrenaline (norepinephrine) (p = 0.005) and lactate levels (p = 0.0005) may have contributed to the early post-exercise stabilisation of glycaemia in the sprint trial. During recovery, adrenaline (epinephrine) and NEFA levels increased marginally in the sprint trial, but other counter-regulatory hormones did not change significantly (p < 0.05). A 10-s sprint performed immediately prior to moderate-intensity exercise prevents glycaemia from falling during early recovery from moderate-intensity exercise in individuals with type 1 diabetes.

Exercise training modalities in chronic heart failure: does high intensity aerobic interval training make the difference?

PubMed

Giallauria, Francesco; Smart, Neil Andrew; Cittadini, Antonio; Vigorito, Carlo

2016-10-14

Exercise training (ET) is strongly recommended in patients with chronic heart failure (CHF). Moderate-intensity aerobic continuous ET is the best established training modality in CHF patients. In the last decade, however, high-intensity interval exercise training (HIIT) has aroused considerable interest in cardiac rehabilitation community. Basically, HIIT consists of repeated bouts of high-intensity exercise alternated with recovery periods. In CHF patients, HIIT exerts larger improvements in exercise capacity compared to moderate-continuous ET. These results are intriguing, mostly considering that better functional capacity translates into an improvement of symptoms and quality of life. Notably, HIIT did not reveal major safety issues; although CHF patients should be clinically stable, have had recent exposure to at least regular moderate-intensity exercise, and appropriate supervision and monitoring during and after the exercise session are mandatory. The impact of HIIT on cardiac dimensions and function and on endothelial function remains uncertain. HIIT should not replace other training modalities in heart failure but should rather complement them. Combining and tailoring different ET modalities according to each patient's baseline clinical characteristics (i.e. exercise capacity, personal needs, preferences and goals) seem the most astute approach to exercise prescription.

Effect of gender on fatigue and recovery following maximal intensity repeated sprint performance.

PubMed

Laurent, C M; Green, J M; Bishop, P A; Sjökvist, J; Schumacker, R E; Richardson, M T; Curtner-Smith, M

2010-09-01

This study investigated the effects of gender on repeated, maximal-intensity intermittent sprint exercise following variable day-to-day recovery periods. Sixteen volunteers (8 men, 8 women) performed four trials of high-intensity intermittent sprint exercise consisting of three bouts of eight 30 m sprints (total of 24 sprints). Following completion of the baseline trial, in repeated-measures design, participants were assigned, in counter-balanced order, variable recovery periods of 24, 48, and 72 h whereupon they repeated an identical exercise trial. Results from a series of 4 (trial) x 3 (bout) repeated measures ANOVAs revealed men produced significantly (P < 0.01) faster times throughout all bouts and trials of repeated sprint exercise. Additionally, women exhibited significantly lower (P < 0.05) blood lactate concentration and significantly lower (P < 0.05) decrement in performance, indicating increased resistance to fatigue during repeated exercise sessions. There were no significant differences (P > 0.05) between genders for heart rate or rating of perceived exertion during or following trials. There were no significant differences for overall sprint performance within either gender among trials. These results indicate men, while able to produce higher absolute power outputs (i.e., lower sprint time), demonstrate higher decrement scores within a trial compared to women, thus suggesting women may recover faster and fatigue less. Also, gender differences affecting recovery within in a trial were observed to be diminished between trials (i.e., day-to-day recovery) of maximal intermittent sprint work evidenced by the observed stability of performance between trials following various recovery durations.

Eccentric resistance training intensity may affect the severity of exercise induced muscle damage.

PubMed

Hasenoehrl, Timothy; Wessner, Barbara; Tschan, Harald; Vidotto, Claudia; Crevenna, Richard; Csapo, Robert

2017-09-01

The aim of the present study was to assess the role of eccentric exercise intensity in the development of and recovery from delayed onset muscle soreness (DOMS). Using a cross-over study design, 15 healthy, male college students were tested on two occasions. The training stimulus consisted of an exhaustive series of eccentric muscle contractions of the elbow flexors at either 100% (high intensity) or 50% (low intensity) of the individual concentric one-repetition maximum. Blood samples were taken at baseline as well as 24, 48, 72 and 96 hours postexercise, and analyzed for creatine kinase, myoglobin, interleukin-6 and prostaglandin-2. Additionally, upper arm circumference (CIRC) and DOMS-related sensation of pain (PAIN) were measured. Following high intensity training, CIRC was significantly greater (P=0.007). Further, creatine kinase, myoglobin and interleukin-6 tended to be higher, although the main effect of the factor "intensity" just failed to reach significance (creatine kinase: P=0.056, myoglobin: P=0.064, interleukin-6: P=0.091). No differences were found for prostaglandin-2 (P=0.783) and PAIN (P=0.147). When performed at greater intensity, fatiguing eccentric resistance exercise of the elbow flexors leads to greater muscle swelling and, potentially, increases in serum markers reflecting lesions in the muscle's cellular membrane.

Is Moderate Intensity Exercise Training Combined with High Intensity Interval Training More Effective at Improving Cardiorespiratory Fitness than Moderate Intensity Exercise Training Alone?

PubMed Central

Roxburgh, Brendon H.; Nolan, Paul B.; Weatherwax, Ryan M.; Dalleck, Lance C.

2014-01-01

The purpose of this study was to compare the effectiveness of either continuous moderate intensity exercise training (CMIET) alone vs. CMIET combined with a single weekly bout of high intensity interval training (HIIT) on cardiorespiratory fitness. Twenty nine sedentary participants (36.3 ± 6.9 yrs) at moderate risk of cardiovascular disease were recruited for 12 weeks of exercise training on a treadmill and cycle ergometer. Participants were randomised into three groups: CMIET + HIIT (n = 7; 8-12 x 60 sec at 100% VO2max, 150 sec active recovery), CMIET (n = 6; 30 min at 45-60% oxygen consumption reserve (VO2R)) and a sedentary control group (n = 7). Participants in the CMIET + HIIT group performed a single weekly bout of HIIT and four weekly sessions of CMIET, whilst the CMIET group performed five weekly CMIET sessions. Probabilistic magnitude-based inferences were determined to assess the likelihood that the true value of the effect represents substantial change. Relative VO2max increased by 10.1% (benefit possible relative to control) in in the CMIET + HIIT group (32.7 ± 9.2 to 36.0 ± 11.5 mL·kg-1·min-1) and 3.9% (benefit possible relative to control) in the CMIET group (33.2 ± 4.0 to 34.5 ± 6.1 mL·kg-1·min-1), whilst there was a 5.7% decrease in the control group (30.0 ± 4.6 to 28.3 ± 6.5 mL·kg-1·min-1). It was ‘unclear’ if a clinically significant difference existed between the effect of CMIET + HIIT and CMIET on the change in VO2max. Both exercising groups showed clinically meaningful improvements in VO2max. Nevertheless, it remains ‘unclear’ whether one type of exercise training regimen elicits a superior improvement in cardiorespiratory fitness relative to its counterpart. Key Points Both continuous moderate intensity exercise training (CMIET) alone and CMIET combined with a single weekly bout of high intensity interval training (CMIET + HIIT) elicit ‘possibly beneficial’ clinically meaningful improvements in cardiorespiratory fitness. Cardiorespiratory fitness improved by ~1.0 MET in the CMIET + HIIT exercise intervention group, which likely leads to important long-term prevention implications as a 1 MET increase in cardiorespiratory fitness has been linked with an 18% reduction in deaths due to CVD. There was 100% adherence to interval sessions in the CMIET + HIIT group, suggesting this combination of training can be well-tolerated in previously inactive overweight/obese individuals. PMID:25177202

The effects of short term detraining and retraining on physical fitness in elite soccer players

PubMed Central

2018-01-01

Purpose The aim of this study was to examine the effects of aerobic high-intensity training with reduced volume and training cessation on body composition and physical fitness after the end of season and the time required to recapture physical fitness with intensified retraining following two weeks of detraining in elite soccer players. Method Twenty male semi-professional soccer players participated in this study. The soccer players were assigned to either a group that completed high-intensity aerobic training (HAT, n = 10) or to a detraining and retraining group (DHAT, n = 10) for a 5-week period immediately after the end of the season. The first 2 weeks of the period, members of the HAT group performed high-intensity aerobic exercise (80–90% of HRmax, 12 min × 3, three times per week), whereas members of the DHAT group abstained from any physical activity. During the subsequent 3 weeks, members of both the HAT and DHAT groups completed high-intensity aerobic exercise. Exercise performance testing and body composition analysis were performed before; after 2 weeks of detraining; and at 1, 2 and 3 weeks of retraining. Results Intensified high-intensity training for 5 weeks maintained the performance in the Yo-Yo Intermittent Recovery level 2 test (Yo-Yo IR2) and repeated sprints at any time point (P > 0.05). However 2 weeks of detraining resulted in significant decreases in the performance on the Yo-Yo IR2 (P < 0.01) and repeated sprints test (P < 0.05). Performance on the Yo-Yo IR2 enhanced after 2 weeks of retraining and was maintained up to 3 weeks after retraining, with no significant differences between conditions (P > 0.05). In addition, repeated sprint performance markedly decreased after the detraining period (P < 0.05) and was continuously lower compared to the baseline at 2 weeks after retraining (P < 0.05). Furthermore, this value reached baseline level at the end of the experimental period (P > 0.05). There were no significant differences between conditions in body composition, performance of agility, or sprint ability throughout the 5-week experimental period (P > 0.05). Conclusions The present data suggest that short-term detraining after the competitive season can markedly decrease performances in the Yo-Yo IR2 test and repeated sprints. To return to a previous level of ability on the Yo-Yo IR2 and/or sprint test with retraining through high-intensity aerobic training after a period of detraining, a similar or longer period of retraining is required. However, the high-intensity training with reduced amount of training after competitive season can prevent reductions in physical fitness. PMID:29746505

Critical Power: An Important Fatigue Threshold in Exercise Physiology

PubMed Central

Poole, David C.; Burnley, Mark; Vanhatalo, Anni; Rossiter, Harry B.; Jones, Andrew M.

2016-01-01

The hyperbolic form of the power-duration relationship is rigorous and highly conserved across species, forms of exercise and individual muscles/muscle groups. For modalities such as cycling, the relationship resolves to two parameters, the asymptote for power (critical power, CP) and the so-called W′ (work doable above CP), which together predict the tolerable duration of exercise above CP. Crucially, the CP concept integrates sentinel physiological profiles - respiratory, metabolic and contractile - within a coherent framework that has great scientific and practical utility. Rather than calibrating equivalent exercise intensities relative to metabolically distant parameters such as the lactate threshold or V̇O2 max, setting the exercise intensity relative to CP unifies the profile of systemic and intramuscular responses and, if greater than CP, predicts the tolerable duration of exercise until W′ is expended, V̇O2 max is attained, and intolerance is manifested. CP may be regarded as a ‘fatigue threshold’ in the sense that it separates exercise intensity domains within which the physiological responses to exercise can (CP) be stabilized. The CP concept therefore enables important insights into 1) the principal loci of fatigue development (central vs. peripheral) at different intensities of exercise, and 2) mechanisms of cardiovascular and metabolic control and their modulation by factors such as O2 delivery. Practically, the CP concept has great potential application in optimizing athletic training programs and performance as well as improving the life quality for individuals enduring chronic disease. PMID:27031742

Critical Power: An Important Fatigue Threshold in Exercise Physiology.

PubMed

Poole, David C; Burnley, Mark; Vanhatalo, Anni; Rossiter, Harry B; Jones, Andrew M

2016-11-01

: The hyperbolic form of the power-duration relationship is rigorous and highly conserved across species, forms of exercise, and individual muscles/muscle groups. For modalities such as cycling, the relationship resolves to two parameters, the asymptote for power (critical power [CP]) and the so-called W' (work doable above CP), which together predict the tolerable duration of exercise above CP. Crucially, the CP concept integrates sentinel physiological profiles-respiratory, metabolic, and contractile-within a coherent framework that has great scientific and practical utility. Rather than calibrating equivalent exercise intensities relative to metabolically distant parameters such as the lactate threshold or V˙O2max, setting the exercise intensity relative to CP unifies the profile of systemic and intramuscular responses and, if greater than CP, predicts the tolerable duration of exercise until W' is expended, V˙O2max is attained, and intolerance is manifested. CP may be regarded as a "fatigue threshold" in the sense that it separates exercise intensity domains within which the physiological responses to exercise can (CP) be stabilized. The CP concept therefore enables important insights into 1) the principal loci of fatigue development (central vs. peripheral) at different intensities of exercise and 2) mechanisms of cardiovascular and metabolic control and their modulation by factors such as O2 delivery. Practically, the CP concept has great potential application in optimizing athletic training programs and performance as well as improving the life quality for individuals enduring chronic disease.

Benefits, Consequences, and Uncertainties of Conventional (Exercise) Countermeasure Approaches

NASA Technical Reports Server (NTRS)

Ploutz-Snyder, Lori

2013-01-01

This presentation will review the pros, cons, and uncertainties of using exercise countermeasures in hypothetical long duration exploration missions. The use of artificial gravity and exercise will be briefly discussed. One benefit to continued use of exercise is related to our extensive experience with spaceflight exercise hardware and programming. Exercise has been a part of each space mission dating back to the 1960's when simple isometric and bungee exercises were performed in the Gemini capsule. Over the next 50 years, exercise hardware improved cumulating in today's ISS suite of exercise equipment: Cycle Ergometer with Vibration Isolation and Stabilization System (CEVIS), Treadmill (T2) and Advanced Resistive Exercise Device (ARED). Today's exercise equipment is the most robust ever to be flown in space and allows the variety and intensity of exercise that might reasonably be expected to maintain muscle mass and function, bone density and cardiovascular fitness. A second benefit is related to the large body of research literature on exercise training. There is a considerable body of supporting research literature including >40,000 peer reviewed research articles on exercise training in humans. A third benefit of exercise is its effectiveness. With the addition of T2 and ARED to our ISS exercise suite, crew member outcomes on standard medical tests have improved. Additionally exercise has other positive side effects such as stress relief, possible improvement of immune function, improved sleep, etc. Exercise is not without its consequences. The major cons to performance of in-flight exercise are the time and equipment required. Currently crew are scheduled 2.5 hrs/day for exercise and there is considerable cost to develop, fly and maintain exercise hardware. While no major injuries have been reported on ISS, there is always some risk of injury with any form of exercise There are several uncertainties going forward; these relate mostly to the development of small compact robust effective exercise devices for the next generation of space vehicles. It is becoming increasingly apparent that high intensity exercise is required for maintenance of fitness and functional capability and so future hardware will need to be developed, tested and implemented that allow for a wide variety of exercise, at high intensity while likely involving low mass, volume and power. There are many unanswered issues related to the minimum number and type of exercise devices required for exploration, optimizing exercise prescriptions for these devices, whether a treadmill is absolutely required, and even whether any single countermeasure can adequately protect muscle, bone, cardiovascular and sensorimotor function.

Effect of Exercise Intensity and Duration on Postexercise Executive Function.

PubMed

Tsukamoto, Hayato; Takenaka, Saki; Suga, Tadashi; Tanaka, Daichi; Takeuchi, Tatsuya; Hamaoka, Takafumi; Isaka, Tadao; Hashimoto, Takeshi

2017-04-01

The effect of exercise volume represented by exercise intensity and duration on postexercise executive function (EF) improvement remains unclear. In the present study, involving two volume-controlled evaluations, we aimed to compare acute exercise protocols with differing intensities and durations to establish an effective exercise protocol for improving EF. In study 1, 12 healthy male subjects performed cycle ergometer exercise, based on a low-intensity (LI) protocol for 20 min (LI20), moderate-intensity (MI) protocol for 20 min (MI20), and MI20 volume-matched LI protocol for 40 min (LI40). The exercise intensities for the LI and MI were set at 30% and 60% of peak oxygen consumption, respectively. In study 2, 15 healthy male subjects performed MI exercise for 10 min (MI10), MI20, and 40 min (MI40). To evaluate the EF, the color-word Stroop task was administrated before exercise, immediately after exercise, and during the 30-min postexercise recovery. In study 1, postexercise EF improvement was sustained for a longer duration after MI20 than after LI40 and was sustained for a longer duration after LI40 than after LI20. In study 2, although there was no significant difference in post-MI exercise EF improvement, the magnitude of difference in the EF between preexercise and 30-min postexercise recovery period was moderately larger in MI40, but not in MI10 and MI20, indicating that the EF improvement during postexercise recovery could be sustained after MI40. The present findings showed that postexercise EF improvement could be prolonged after MI exercise with a moderate duration compared with volume-matched LI exercise with a longer duration. In addition, MI exercise with a relatively long duration may slightly prolong the postexercise EF improvement.

Impact of neuromuscular fatigue on match exercise intensity and performance in elite Australian football.

PubMed

Mooney, Mitchell G; Cormack, Stuart; Oʼbrien, Brendan J; Morgan, William M; McGuigan, Mike

2013-01-01

This study aimed to quantify the influence of neuromuscular fatigue (NMF) via flight time to contraction time ratio (FT:CT) obtained from a countermovement jump (CMJ) on the relationships between yo-yo intermittent recovery (level 2) test (yo-yo IR2), match exercise intensity (high-intensity running [HIR] m·min(-1) and Load·min(-1)) and Australian football (AF) performance. Thirty-seven data sets were collected from 17 different players across 22 elite AF matches. Each data set comprised an athlete's yo-yo IR2 score before the start of the season, match exercise intensity via global positioning system and on-field performance rated by coaches' votes and number of ball disposals. Each data set was categorized as normal (>92% baseline FT:CT, n = 20) or fatigued (<92% baseline FT:CT, n = 17) from a single CMJ performed 96 hours after the previous match. Moderation-mediation analysis was completed with yo-yo IR2 (independent variable), match exercise intensity (mediator), and AF performance (dependent variable) with NMF status as the conditional variable. Isolated interactions between variables were analyzed by Pearson's correlation and effect size statistics. The Yo-yo IR2 score showed an indirect influence on the number of ball disposals via HIR m·min(-1) regardless of NMF status (normal FT:CT indirect effect = 0.019, p < 0.1, reduced FT:CT indirect effect = 0.022, p < 0.1). However, the yo-yo IR2 score only influenced coaches' votes via Load·min(-1) in the nonfatigued state (normal: FT:CT indirect effect = 0.007, p <0.1, reduced: FT:CT indirect effect = -0.001, p > 0.1). In isolation, NMF status also reduces relationships between yo-yo IR2 and load·min(-1), yo-yo IR2 and coaches votes, Load·min(-1) and coaches' votes (Δr > 0.1). Routinely testing yo-yo IR2 capacity, NMF via FT:CT and monitoring Load·min(-1) in conjunction with HIR m·min(-1) as exercise intensity measures in elite AF is recommended.

Low- Versus High-Intensity Plyometric Exercise During Rehabilitation After Anterior Cruciate Ligament Reconstruction.

PubMed

Chmielewski, Terese L; George, Steven Z; Tillman, Susan M; Moser, Michael W; Lentz, Trevor A; Indelicato, Peter A; Trumble, Troy N; Shuster, Jonathan J; Cicuttini, Flavia M; Leeuwenburgh, Christiaan

2016-03-01

Plyometric exercise is used during rehabilitation after anterior cruciate ligament (ACL) reconstruction to facilitate the return to sports participation. However, clinical outcomes have not been examined, and high loads on the lower extremity could be detrimental to knee articular cartilage. To compare the immediate effect of low- and high-intensity plyometric exercise during rehabilitation after ACL reconstruction on knee function, articular cartilage metabolism, and other clinically relevant measures. Randomized controlled trial; Level of evidence, 2. Twenty-four patients who underwent unilateral ACL reconstruction (mean, 14.3 weeks after surgery; range, 12.1-17.7 weeks) were assigned to 8 weeks (16 visits) of low- or high-intensity plyometric exercise consisting of running, jumping, and agility activities. Groups were distinguished by the expected magnitude of vertical ground-reaction forces. Testing was conducted before and after the intervention. Primary outcomes were self-reported knee function (International Knee Documentation Committee [IKDC] subjective knee form) and a biomarker of articular cartilage degradation (urine concentrations of crosslinked C-telopeptide fragments of type II collagen [uCTX-II]). Secondary outcomes included additional biomarkers of articular cartilage metabolism (urinary concentrations of the neoepitope of type II collagen cleavage at the C-terminal three-quarter-length fragment [uC2C], serum concentrations of the C-terminal propeptide of newly formed type II collagen [sCPII]) and inflammation (tumor necrosis factor-α), functional performance (maximal vertical jump and single-legged hop), knee impairments (anterior knee laxity, average knee pain intensity, normalized quadriceps strength, quadriceps symmetry index), and psychosocial status (kinesiophobia, knee activity self-efficacy, pain catastrophizing). The change in each measure was compared between groups. Values before and after the intervention were compared with the groups combined. The groups did not significantly differ in the change of any primary or secondary outcome measure. Of interest, sCPII concentrations tended to change in opposite directions (mean ± SD: low-intensity group, 28.7 ± 185.5 ng/mL; high-intensity group, -200.6 ± 255.0 ng/mL; P = .097; Cohen d = 1.03). Across groups, significant changes after the intervention were increased the IKDC score, vertical jump height, normalized quadriceps strength, quadriceps symmetry index, and knee activity self-efficacy and decreased average knee pain intensity. No significant differences were detected between the low- and high-intensity plyometric exercise groups. Across both groups, plyometric exercise induced positive changes in knee function, knee impairments, and psychosocial status that would support the return to sports participation after ACL reconstruction. The effect of plyometric exercise intensity on articular cartilage requires further evaluation. Clinicaltrials.gov NCT01851655. © 2016 The Author(s).

Muscle Activation During Exercise in Severe Acute Hypoxia: Role of Absolute and Relative Intensity

PubMed Central

Torres-Peralta, Rafael; Losa-Reyna, José; González-Izal, Miriam; Perez-Suarez, Ismael; Calle-Herrero, Jaime; Izquierdo, Mikel

2014-01-01

Abstract Torres-Peralta, Rafael, José Losa-Reyna, Miriam González-Izal, Ismael Perez-Suarez, Jaime Calle-Herrero, Mikel Izquierdo, and José A.L. Calbet. Muscle activation during exercise in severe acute hypoxia: Role of absolute and relative intensity. High Alt Med Biol 15:472–482, 2014.—The aim of this study was to determine the influence of severe acute hypoxia on muscle activation during whole body dynamic exercise. Eleven young men performed four incremental cycle ergometer tests to exhaustion breathing normoxic (FIo2=0.21, two tests) or hypoxic gas (FIo2=0.108, two tests). Surface electromyography (EMG) activities of rectus femoris (RF), vastus medialis (VL), vastus lateralis (VL), and biceps femoris (BF) were recorded. The two normoxic and the two hypoxic tests were averaged to reduce EMG variability. Peak Vo2 was 34% lower in hypoxia than in normoxia (p<0.05). The EMG root mean square (RMS) increased with exercise intensity in all muscles (p<0.05), with greater effect in hypoxia than in normoxia in the RF and VM (p<0.05), and a similar trend in VL (p=0.10). At the same relative intensity, the RMS was greater in normoxia than in hypoxia in RF, VL, and BF (p<0.05), with a similar trend in VM (p=0.08). Median frequency increased with exercise intensity (p<0.05), and was higher in hypoxia than in normoxia in VL (p<0.05). Muscle contraction burst duration increased with exercise intensity in VM and VL (p<0.05), without clear effects of FIo2. No significant FIo2 effects on frequency domain indices were observed when compared at the same relative intensity. In conclusion, muscle activation during whole body exercise increases almost linearly with exercise intensity, following a muscle-specific pattern, which is adjusted depending on the FIo2 and the relative intensity of exercise. Both VL and VM are increasingly involved in power output generation with the increase of intensity and the reduction in FIo2. PMID:25225839

Two-dimensional strain echocardiography technology for evaluation of myocardial strain in swimming athletes after high-intensity exercise.

PubMed

Liang, Chen; Ma, Yun; Gao, Can; Zhang, Jianhong; Yang, Min; Chen, Gen; Fu, Shan; Zhu, Tiangang

2017-02-01

The aim of this study was to investigate the change in myocardial strain in swimming athletes before and after high-intensity exercise using two-dimensional strain echocardiography (2DSE) technology. To assess whether the local and overall myocardial function and myocardial injury are accurately measured using 2DSE technology, 15 swimming athletes were selected as research objects. We applied 2DSE technology to track the 2D ultrasound images of the apical four chambers, the apical two chambers, and the apical long axis before and after high-intensity, increasing-load exercise. We recorded indices such as the left ventricular global strain (GS) and the left ventricular segmental wall longitudinal peak systolic strain (PS) in 18 systoles and analyzed the myocardial strain change before and after exercise. After high-intensity exercise, the overall myocardial strain decreased, especially the strain of the posterior wall, posterior divider, lateral wall, lower wall, and the basal and middle segments of the anterior wall. The influence of exercise on myocardial strain was greater on the basal and middle segments than on the apical segment. One-time intensive exercise negatively affected the myocardial muscle. Myocardial muscles in the apical segment and the myocardial wall were more sensitive to intensive exercise. The 2DSE technology can precisely position the motion-sensitive areas and help locate myocardial injury. © 2017, Wiley Periodicals, Inc.

Effect of body composition, aerobic performance and physical activity on exercise-induced oxidative stress in healthy subjects.

PubMed

Więcek, Magdalena; Maciejczyk, Marcin; Szymura, Jadwiga; Wiecha, Szczepan; Kantorowicz, Malgorzata; Szygula, Zbigniew

2017-01-01

Oxidative stress could be the result of an increase in ATP resynthesis during exercise. The aim of the study was to compare prooxidant-antioxidant balance (PAB) disturbances induced by exercise at maximal intensity in young men with differing body compositions. Thirty-nine subjects were selected from 1549 volunteers aged 18-30, based on lean body mass (LBM) and body fat percentage (%BF), and then assigned into one of the following groups: control group (CON), including subjects with average LBM (59.0-64.3 kg) and average %BF (14.0-18.5%); high body fat (HBF) group, including subjects with high %BF (>21.5%) and average LBM; and high lean body mass (HLBM) group, including subjects with high LBM (>66.3 kg) and average %BF. Participants' physical activity was determined. A running test with a gradually increased load was used. Before and 3 minutes after exercise, total oxidative status (TOS) and total antioxidant capacity (TAC) were determined in the plasma, and the Oxidative Stress Index (OSI = TOS/TAC) was calculated. Maximal oxygen uptake (VO2max) was comparable in the HBF and HLBM groups (53.12±1.51 mL/kg and 50.25±1.27 mL/kg, respectively) and significantly lower compared to the CON group (58.23±1.62 mL/kg). The CON, HBF and HLBM groups showed similar significant (P<0.05) increases in TOS levels (36%, 35% and 31%, respectively). Post-exercise TAC increased by 8% in the HBF and HLBM groups (P<0.05), compared to the 3% increase in the CON group (P>0.05). There was significant negative correlation between OSI, measured before and after exercise, and participants' physical activity. There was no correlation between OSI and VO2max, BM, LBM, %BF and BMI. Exercise at maximal intensity causes a similar increase in TOS and in TAC in subjects with increased %BF and elevated content of LBM and regardless of body composition, the ratios of TOS/TAC concentrations before and after maximal-intensity exercise, have lower values in people with higher physical activity levels and are not dependent on aerobic performance (VO2max).

[Exercise-related risk at anaerobic threshold in patients with chronic obstructive pulmonary disease].

PubMed

Xu, Q F; Yuan, W; Zhao, X J; Li, B; Wang, H Y

2016-02-01

To investigate the exercise-related risk at anaerobic threshold(AT) in patients with chronic obstructive pulmonary disease(COPD). Sixty two patients [men 56, women 6, aged (66±8) yr] with stable COPD in Beijing Friendship Hospital during 2013-2014, participated in this study. Incremental symptom-limited cardiopulmonary exercise test was performed on cycle ergometer. The AT was determined using the V-Slope technique and ventilatory equivalents for carbon dioxide and oxygen. Symptoms, 10-lead electrocardiogram, oxygen saturation by pulse oximetry(SpO(2)) were monitored during exercise. The AT, detectable in 53 patients, occurred at (68±10)% of peak oxygen uptake(peak VO(2)). The SpO(2) was in the safe range (94±2) % and the respiratory reserve was relatively high at AT (i.e. 48%). High-intensity exercise training can be performed in patients with moderate-to- severe COPD without resting oxygen desaturation.

Comparisons of low-intensity versus moderate-intensity combined aerobic and resistance training on body composition, muscle strength, and functional performance in older women.

PubMed

Shiotsu, Yoko; Yanagita, Masahiko

2018-06-01

This study aimed to examine the effects of exercise order of combined aerobic and low- or moderate-intensity resistance training into the same session on body composition, functional performance, and muscle strength in healthy older women. Furthermore, this study compared the effects of different (low- vs moderate-) intensity combined training. A total of 60 healthy older women (age 61-81 y) were randomly assigned to five groups that performed aerobic exercise before low-intensity resistance training (AR-L, n = 12) or after resistance training (RA-L, n = 12), performed aerobic exercise before moderate-intensity resistance training (AR-M, n = 12) or after resistance training (RA-M, n = 12), or nonintervention control conditions (CON, n = 12). Body composition, functional performance, and muscle strength were evaluated before and after the 10-week training. No effects of exercise order of combined aerobic and low- or moderate-intensity resistance training (AR-L vs RA-L, AR-M vs RA-M) were observed in body composition, functional performance, or muscle strength, whereas the effects of training intensity of combined training (AR-L vs AR-M, RA-L vs RA-M) were observed on functional performance. All combined trainings significantly increased muscle strength and gait ability (P < 0.01, respectively). Functional reach test significantly increased in the AR-M and RA-M groups (P < 0.01, respectively), and there were significant group differences between AR-L and AR-M (P = 0.002), RA-L and RA-M (P = 0.014). Preliminary findings suggest that combined aerobic and low- or moderate-intensity resistance training increases muscle strength and improves gait ability, regardless of the exercise order. Also, greater improvement in dynamic balance capacity, a risk factor associated with falling, is observed in moderate-intensity combined training.

A Methodological Approach to Quantifying Plyometric Intensity.

PubMed

Jarvis, Mark M; Graham-Smith, Phil; Comfort, Paul

2016-09-01

Jarvis, MM, Graham-Smith, P, and Comfort, P. A Methodological approach to quantifying plyometric intensity. J Strength Cond Res 30(9): 2522-2532, 2016-In contrast to other methods of training, the quantification of plyometric exercise intensity is poorly defined. The purpose of this study was to evaluate the suitability of a range of neuromuscular and mechanical variables to describe the intensity of plyometric exercises. Seven male recreationally active subjects performed a series of 7 plyometric exercises. Neuromuscular activity was measured using surface electromyography (SEMG) at vastus lateralis (VL) and biceps femoris (BF). Surface electromyography data were divided into concentric (CON) and eccentric (ECC) phases of movement. Mechanical output was measured by ground reaction forces and processed to provide peak impact ground reaction force (PF), peak eccentric power (PEP), and impulse (IMP). Statistical analysis was conducted to assess the reliability intraclass correlation coefficient and sensitivity smallest detectable difference of all variables. Mean values of SEMG demonstrate high reliability (r ≥ 0.82), excluding ECC VL during a 40-cm drop jump (r = 0.74). PF, PEP, and IMP demonstrated high reliability (r ≥ 0.85). Statistical power for force variables was excellent (power = 1.0), and good for SEMG (power ≥0.86) excluding CON BF (power = 0.57). There was no significant difference (p > 0.05) in CON SEMG between exercises. Eccentric phase SEMG only distinguished between exercises involving a landing and those that did not (percentage of maximal voluntary isometric contraction [%MVIC] = no landing -65 ± 5, landing -140 ± 8). Peak eccentric power, PF, and IMP all distinguished between exercises. In conclusion, CON neuromuscular activity does not appear to vary when intent is maximal, whereas ECC activity is dependent on the presence of a landing. Force characteristics provide a reliable and sensitive measure enabling precise description of intensity in plyometric exercises. The present findings provide coaches and scientists with an insightful and precise method of measuring intensity in plyometrics, which will allow for greater control of programming variables.

Comparison of affective responses during and after low volume high-intensity interval exercise, continuous moderate- and continuous high-intensity exercise in active, untrained, healthy males.

PubMed

Niven, Ailsa; Thow, Jacqueline; Holroyd, Jack; Turner, Anthony P; Phillips, Shaun M

2018-09-01

This study compared affective responses to low volume high-intensity interval exercise (HIIE), moderate-intensity continuous exercise (MICE) and high-intensity continuous exercise (HICE). Twelve untrained males ([Formula: see text] 48.2 ± 6.7 ml·kg -1 ·min -1 ) completed MICE (30 min cycle at 85% of ventilatory threshold (VT)), HICE (cycle at 105% of VT matched with MICE for total work), and HIIE (10 x 6 s cycle sprints with 60 s recovery). Affective valence and perceived activation were measured before exercise, post warm-up, every 20% of exercise time, and 1, 5, 10, and 15 min post-exercise. Affective valence during exercise declined by 1.75 ± 2.42, 1.17 ± 1.99, and 0.42 ± 1.38 units in HICE, HIIE, and MICE, respectively, but was not statistically influenced by trial (P = 0.35), time (P = 0.06), or interaction effect (P = 0.08). Affective valence during HICE and HIIE was consistently less positive than MICE. Affective valence post-exercise was not statistically influenced by trial (P = 0.10) and at 5 min post-exercise exceeded end-exercise values (P = 0.048). Circumplex profiles showed no negative affect in any trial. Affective responses to low volume HIIE are similar to HICE but remain positive and rebound rapidly, suggesting it may be a potential alternative exercise prescription.

Changes in body composition of high competition rugby players during the phases of a regular season; influence of diet and exercise load.

PubMed

García, M; Martínez-Moreno, J M; Reyes-Ortiz, A; Suarez Moreno-Arrones, L; García A, A; Garcíacaballero, M

2014-04-01

Top athletes are subjected to intense training to achieve high performance. There are factors such as diet and strenuous exercise that affects body composition and can modify the performance. The aim of the study was to evaluate the effect of a personalized plan of diet and training on body composition. We studied the body composition of 18 professional rugby players using Kinanthropometry parameters. The study was conducted from the preseason to the end of the season taking into account the position of the player for measuring exercise intensity, and developing a personalized nutritional and training plan to each player. At baseline the players were away from the internationally recommended body composition, with high percentages of body fat. Appropriate and personalized diet plans and training custom achieved fat percentages close to those recommended. The personalized program of diet and training directed has adequate leverage to improve all parameters studied them bringing them as close to the ideal. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

Muscle Adaptations Following Short-Duration Bed Rest with Integrated Resistance, Interval, and Aerobic Exercise

NASA Technical Reports Server (NTRS)

Hackney, Kyle J.; Scott, Jessica M.; Buxton, Roxanne; Redd-Goetchius, Elizabeth; Crowell, J. Brent; Everett, Meghan E.; Wickwire, Jason; Ryder, Jeffrey W.; Bloomberg, Jacob J.; Ploutz-Snyder, Lori L.

2011-01-01

Unloading of the musculoskeletal system during space flight results in deconditioning that may impair mission-related task performance in astronauts. Exercise countermeasures have been frequently tested during bed rest (BR) and limb suspension; however, high-intensity, short-duration exercise prescriptions have not been fully explored. PURPOSE: To determine if a high intensity resistance, interval, and aerobic exercise program could protect against muscle atrophy and dysfunction when performed during short duration BR. METHODS: Nine subjects (1 female, 8 male) performed a combination of supine exercises during 2 weeks of horizontal BR. Resistance exercise (3 d / wk) consisted of squat, leg press, hamstring curl, and heel raise exercises (3 sets, 12 repetitions). Aerobic (6 d / wk) sessions alternated continuous (75% VO2 peak) and interval exercise (30 s, 2 min, and 4 min) and were completed on a supine cycle ergometer and vertical treadmill, respectively. Muscle volumes of the upper leg were calculated pre, mid, and post-BR using magnetic resonance imaging. Maximal isometric force (MIF), rate of force development (RFD), and peak power of the lower body extensors were measured twice before BR (averaged to represent pre) and once post BR. ANOVA with repeated measures and a priori planned contrasts were used to test for differences. RESULTS: There were no changes to quadriceps, hamstring, and adductor muscle volumes at mid and post BR time points compared to pre BR (Table 1). Peak power increased significantly from 1614 +/- 372 W to 1739 +/- 359 W post BR (+7.7%, p = 0.035). Neither MIF (pre: 1676 +/- 320 N vs. post: 1711 +/- 250 N, +2.1%, p = 0.333) nor RFD (pre: 7534 +/- 1265 N/ms vs. post: 6951 +/- 1241 N/ms, -7.7%, p = 0.136) were significantly impaired post BR.

Can high-intensity exercise be more pleasant?: attentional dissociation using music and video.

PubMed

Jones, Leighton; Karageorghis, Costas I; Ekkekakis, Panteleimon

2014-10-01

Theories suggest that external stimuli (e.g., auditory and visual) may be rendered ineffective in modulating attention when exercise intensity is high. We examined the effects of music and parkland video footage on psychological measures during and after stationary cycling at two intensities: 10% of maximal capacity below ventilatory threshold and 5% above. Participants (N = 34) were exposed to four conditions at each intensity: music only, video only, music and video, and control. Analyses revealed main effects of condition and exercise intensity for affective valence and perceived activation (p < .001), state attention (p < .05), and exercise enjoyment (p < .001). The music-only and music-and-video conditions led to the highest valence and enjoyment scores during and after exercise regardless of intensity. Findings indicate that attentional manipulations can exert a salient influence on affect and enjoyment even at intensities slightly above ventilatory threshold.

Improved Functional Performance in Individuals With Dementia After a Moderate-Intensity Home-Based Exercise Program: A Randomized Controlled Trial.

PubMed

Dawson, Nicole; Judge, Katherine S; Gerhart, Hayden

2017-03-01

Individuals with dementia (IWDs) experience difficulties across cognitive and functional domains. Nonpharmacological interventions aimed at reducing disability are greatly needed. Exercise is a low-cost and easily implemented approach, but investigation has yielded mixed evidence to date. The purpose of the current study was to evaluate a novel and innovative moderate-intensity functional exercise intervention for IWDs, which was developed using principles from exercise science along with a Strength-Based Approach, consisting of 24 home-based sessions. A randomized, controlled intervention trial with a 2-group pretest and posttest design was used with a sample of 23 community-dwelling IWDs (intervention group: n = 13; comparison group: n = 10). Average age of participants was 73.9 years (standard deviation, 9.1) with mild to moderate cognitive impairment (Mini-Mental State Examination, Mean = 20.8; standard deviation, 5.0). A 99.0% attendance rate indicated high adherence to the moderate-intensity exercise program. Efficacy was examined using multiple linear regression. Group assignment significantly predicted performance in key outcome measures, with IWDs from the intervention group improving in lower extremity strength (B = 5.92, t = 3.26, P = .004), balance (B = 4.04, t = 4.13, P = .001), and fast gait speed (B = .32, t = 2.61, P = .02). These findings indicated IWDs are able to participate in and benefit from a moderate-intensity functional exercise program, consisting of strength and balance activities. The current intervention used a Strength-Based Approach to facilitate implementation of exercise activities that could be completed by the sample. Therefore, integration of these techniques into mainstream clinical practice and research should be feasible with this patient population. Future research directions and implications of these findings also are discussed.

Effects of sleep disturbances on subsequent physical performance.

PubMed

Mougin, F; Simon-Rigaud, M L; Davenne, D; Renaud, A; Garnier, A; Kantelip, J P; Magnin, P

1991-01-01

The purpose of the study was to compare the cardiovascular, respiratory and metabolic responses to exercise of highly endurance trained subjects after 3 different nights i.e. a baseline night, a partial sleep deprivation of 3 h in the middle of the night and a 0.25-mg triazolam-induced sleep. Sleep-waking chronobiology and endurance performance capacity were taken into account in the choice of the subjects. Seven subjects exercised on a cycle ergometer for a 10-min warm-up, then for 20 min at a steady exercise intensity (equal to the intensity corresponding to 75% of the predetermined maximal oxygen consumption) followed by an increased intensity until exhaustion. The night with 3 h sleep loss was accompanied by a greater number of periods of wakefulness (P less than 0.01) and fewer periods of stage 2 sleep (P less than 0.05) compared with the results recorded during the baseline night. Triazolam-induced sleep led to an increase in stage 2 sleep (P less than 0.05), a decrease in wakefulness (P less than 0.05) and in stage 3 sleep (P less than 0.05). After partial sleep deprivation, there were statistically significant increases in heart rate (P less than 0.05) and ventilation (P less than 0.05) at submaximal exercise compared with results obtained after the baseline night. Both variables were also significantly enhanced at maximal exercise, while the peak oxygen consumption (VO2) dropped (P less than 0.05) even though the maximal sustained exercise intensity was not different.(ABSTRACT TRUNCATED AT 250 WORDS)

Intensive walking exercise for lower extremity peripheral arterial disease: A systematic review and meta-analysis.

PubMed

Lyu, Xiafei; Li, Sheyu; Peng, Shifeng; Cai, Huimin; Liu, Guanjian; Ran, Xingwu

2016-05-01

Supervised treadmill exercise is the recommended therapy for peripheral arterial disease (PAD) patients with intermittent claudication (IC). However, most PAD patients do not exhibit typical symptoms of IC. The aim of the present study was to explore the efficacy and safety of intensive walking exercise in PAD patients with and without IC. The PubMed, Embase and Cochrane Library databases were systematically searched. Randomized controlled trials comparing the effects of intensive walking exercise with usual care in patients with PAD were included for systematic review and meta-analysis. Eighteen trials with 1200 patients were eligible for the present analysis. Compared with usual care, intensive walking exercise significantly improved the maximal walking distance (MWD), pain-free walking distance, and the 6-min walking distance in patients with PAD (P < 0.00001 for all). Subgroup analyses indicated that a lesser improvement in MWD was observed in the subgroup with more diabetes patients, and that the subgroup with better baseline walking ability exhibited greater improvement in walking performance. In addition, similar improvements in walking performance were observed for exercise programs of different durations and modalities. No significant difference was found in adverse events between the intensive walking and usual care groups (relative risk 0.84; 95% confidence interval 0.51, 1.39; P = 0.50). Regardless of exercise length and modality, regularly intensive walking exercise improves walking ability in PAD patients more than usual care. The presence of diabetes may attenuate the improvements in walking performance in patients with PAD following exercise. © 2015 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and Wiley Publishing Asia Pty Ltd.

Effects of elevated core temperature and normoxic 30% nitrous oxide on human ventilation during short duration, high intensity exercise.

PubMed

Yogev, A; Hall, A M; Jay, O; White, M D

2015-01-15

It was hypothesized that normoxic 30% nitrous oxide (N2O) would suppress and hyperthermia would increase exercise ventilation during short duration, high intensity exercise. Thirteen males (24.2±0.8y; mean±SE), of normal physique (BMI, 23.8±1.0kgm(-2)), performed 4 separate 30s Wingate tests on a cycle ergometer. Exercise ventilation and its components, as well as mean skin and esophageal temperature (TES), were assessed in 2 way experimental design with factors of Thermal State (Normothermia or Hyperthermia) and Gas Type (Air or 30% Normomoxic N2O). In the 2 hyperthermic tests TES was elevated to ∼38.5°C in a 40°C bath. The main results indicated a significant interaction (F=7.14, P=0.02) between Gas Type and Thermal state for the exercise-induced increase in ventilation (ΔV˙E). During both the normothermia and hyperthermia conditions with AIR breathing, the exercise ΔV˙E was ∼80Lmin(-1) and it was significantly decreased to 73.1±24.1Lmin(-1) in the normothermia condition with N2O breathing relative to that of 92.0±25.0Lmin(-1) in the hyperthermia condition with N2O breathing. In conclusion, normoxic N2O breathing suppressed high intensity exercise ventilation during normothermia relative to that during hyperthermia on account of decreases in the tidal volume and this led CO2 retention. Copyright © 2014 Elsevier B.V. All rights reserved.

Design and rationale of the HITTS randomized controlled trial: Effect of High-intensity Interval Training in de novo Heart Transplant Recipients in Scandinavia.

PubMed

Nytrøen, Kari; Yardley, Marianne; Rolid, Katrine; Bjørkelund, Elisabeth; Karason, Kristjan; Wigh, Julia Philip; Dall, Christian Have; Arora, Satish; Aakhus, Svend; Lunde, Ketil; Solberg, Ole Geir; Gustafsson, Finn; Prescott, Eva Irene Bossano; Gullestad, Lars

2016-02-01

There is no consensus on how, when, and at what intensity exercise should be performed and organized after heart transplantation (HTx). Most rehabilitation programs are conducted in HTx centers, which might be impractical and costly. We have recently shown that high-intensity interval training (HIT) is safe, well tolerated, and efficacious in maintenance HTx recipients, but there are no studies among de novo patients, and whether HIT is feasible and superior to moderate training in HTx recipients is unclear. A total of 120 clinically stable HTx recipients older than 18 years will be recruited from 3 Scandinavian HTx centers. Participants are randomized to HIT or moderate training, shortly after surgery. All exercises are supervised in the patients' local communities. Testing at baseline and follow-up includes the following: VO2peak (primary end point), muscle strength, body composition, quality of life, myocardial performance, endothelial function, biomarkers, and progression of cardiac allograft vasculopathy. A subgroup (n = 90) will also be tested at 3-year follow-up to assess long-term effects of exercise. So far, the HIT intervention is well tolerated, without any serious adverse events. We aim to test whether decentralized HIT is feasible, safe, and superior to moderate training, and whether it will lead to significant improvement in exercise capacity and less long-term complications. Copyright © 2015 Elsevier Inc. All rights reserved.

Exercise Training During Bed Rest Attenuates Deconditioning

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Hargens, Alan R. (Technical Monitor)

1995-01-01

A 30-day 6 deg. head-down bed rest study was conducted to evaluate high-intensity, short-duration, alternating isotonic cycle ergometer exercise (ITE) training and high-intensity intermittent isokinetic exercise (IKE) training regiments designed to maintain peak VO2 and muscle mass, strength, and endurance at ambulatory control levels throughout prolonged bed rest. Other elements of the deconditioning (acclimation) syndrome, such as proprioception, psychological performance, hypovolemia, water balance, body composition, and orthostatic tolerance, were also measured. Compared with response during bed rest of the no exercise (NOE) control group: the ITE training regimen (a) maintained work capacity (peak VO2), (b) maintained plasma and red cell volume, (c) induced positive body water balance, (d) decreased quality of sleep and mental concentration, and (e) had no effect on the decrease in orthostatic tolerance; the IKE training regimen (a) attenuated the decrease in peak VO2 by 50%, (b) attenuated loss of red cell volume by 40%, but had no effect on loss of plasma volume, (c) induced positive body water balance, (d) had no adverse effect on quality of sleep or concentration, and (e) had no effect on the decrease in orthostatic tolerance. These findings suggest that various elements of the deconditioning syndrome can be manipulated by duration and intensity of ITE or IKE training regiments, and that several different training protocols will be required to maintain or restore physiological and psychological performance of individuals confined to prolonged bed rest.

Antecedent acute cycling exercise affects attention control: an ERP study using attention network test

PubMed Central

Chang, Yu-Kai; Pesce, Caterina; Chiang, Yi-Te; Kuo, Cheng-Yuh; Fong, Dong-Yang

2015-01-01

The purpose of this study was to investigate the after-effects of an acute bout of moderate intensity aerobic cycling exercise on neuroelectric and behavioral indices of efficiency of three attentional networks: alerting, orienting, and executive (conflict) control. Thirty young, highly fit amateur basketball players performed a multifunctional attentional reaction time task, the attention network test (ANT), with a two-group randomized experimental design after an acute bout of moderate intensity spinning wheel exercise or without antecedent exercise. The ANT combined warning signals prior to targets, spatial cueing of potential target locations and target stimuli surrounded by congruent or incongruent flankers, which were provided to assess three attentional networks. Event-related brain potentials and task performance were measured during the ANT. Exercise resulted in a larger P3 amplitude in the alerting and executive control subtasks across frontal, central and parietal midline sites that was paralleled by an enhanced reaction speed only on trials with incongruent flankers of the executive control network. The P3 latency and response accuracy were not affected by exercise. These findings suggest that after spinning, more resources are allocated to task-relevant stimuli in tasks that rely on the alerting and executive control networks. However, the improvement in performance was observed in only the executively challenging conflict condition, suggesting that whether the brain resources that are rendered available immediately after acute exercise translate into better attention performance depends on the cognitive task complexity. PMID:25914634

The differential effects of prolonged exercise upon executive function and cerebral oxygenation.

PubMed

Tempest, Gavin D; Davranche, Karen; Brisswalter, Jeanick; Perrey, Stephane; Radel, Rémi

2017-04-01

The acute-exercise effects upon cognitive functions are varied and dependent upon exercise duration and intensity, and the type of cognitive tasks assessed. The hypofrontality hypothesis assumes that prolonged exercise, at physiologically challenging intensities, is detrimental to executive functions due to cerebral perturbations (indicated by reduced prefrontal activity). The present study aimed to test this hypothesis by measuring oxygenation in prefrontal and motor regions using near-infrared spectroscopy during two executive tasks (flanker task and 2-back task) performed while cycling for 60min at a very low intensity and an intensity above the ventilatory threshold. Findings revealed that, compared to very low intensity, physiologically challenging exercise (i) shortened reaction time in the flanker task, (ii) impaired performance in the 2-back task, and (iii) initially increased oxygenation in prefrontal, but not motor regions, which then became stable in both regions over time. Therefore, during prolonged exercise, not only is the intensity of exercise assessed important, but also the nature of the cognitive processes involved in the task. In contrast to the hypofrontality hypothesis, no inverse pattern of oxygenation between prefrontal and motor regions was observed, and prefrontal oxygenation was maintained over time. The present results go against the hypofrontality hypothesis. Copyright © 2017 Elsevier Inc. All rights reserved.

The effect of various cold-water immersion protocols on exercise-induced inflammatory response and functional recovery from high-intensity sprint exercise.

PubMed

White, Gillian E; Rhind, Shawn G; Wells, Greg D

2014-11-01

The purpose of this study was to investigate the effects of different cold-water immersion (CWI) protocols on the inflammatory response to and functional recovery from high-intensity exercise. Eight healthy recreationally active males completed five trials of a high-intensity intermittent sprint protocol followed by a randomly assigned recovery condition: 1 of 4 CWI protocols (CWI-10 min × 20 °C, CWI-30 min × 20 °C, CWI-10 min × 10 °C, or CWI-30 min × 10 °C) versus passive rest. Circulating mediators of the inflammatory response were measured from EDTA plasma taken pre-exercise (baseline), immediately post-exercise, and at 2, 24, and 48 h post-exercise. Ratings of perceived soreness and impairment were noted on a 10-pt Likert scale, and squat jump and drop jump were performed at these time points. IL-6, IL-8, and MPO increased significantly from baseline immediately post-exercise in all conditions. IL-6 remained elevated from baseline at 2 h in the CWI-30 min × 20 °C, CWI-10 min × 10 °C, and CWI-30 min × 10 °C conditions, while further increases were observed for IL-8 and MPO in the CWI-30 min × 20 °C and CWI-30 min × 10 °C conditions. Squat jump and drop jump height were significantly lower in all conditions immediately post-exercise and at 2 h. Drop jump remained below baseline at 24 and 48 h in the CON and CWI-10 min × 20 °C conditions only, while squat jump height returned to baseline in all conditions. Cold-water immersion appears to facilitate restoration of muscle performance in a stretch-shortening cycle, but not concentric power. These changes do not appear to be related to inflammatory modulation. CWI protocols of excessive duration may actually exacerbate the concentration of cytokines in circulation post-exercise; however, the origin of the circulating cytokines is not necessarily skeletal muscle.

Fatigue during high-intensity intermittent exercise: application to bodybuilding.

PubMed

Lambert, Charles P; Flynn, Michael G

2002-01-01

Resistance exercise is an activity performed by individuals interested in competition, those who wish to improve muscle mass and strength for other sports, and for individuals interested in improving their strength and physical appearance. In this review we present information suggesting that phosphocreatine depletion, intramuscular acidosis and carbohydrate depletion are all potential causes of the fatigue during resistance exercise. In addition, recommendations are provided for nutritional interventions, which might delay muscle fatigue during this type of activity.

Importance of characteristics and modalities of physical activity and exercise in the management of cardiovascular health in individuals with cardiovascular disease (Part III).

PubMed

Vanhees, L; Rauch, B; Piepoli, M; van Buuren, F; Takken, T; Börjesson, M; Bjarnason-Wehrens, B; Doherty, P; Dugmore, D; Halle, M

2012-12-01

The beneficial effect of exercise training and exercise-based cardiac rehabilitation on symptom-free exercise capacity,cardiovascular and skeletal muscle function, quality of life, general healthy lifestyle, and reduction of depressive symptoms and psychosocial stress is nowadays well recognized. However, it remains largely obscure, which characteristics of physical activity (PA) and exercise training--frequency, intensity, time (duration), type (mode), and volume (dose: intensity x duration) of exercise--are the most effective. The present paper, therefore, will deal with these exercise characteristics in the management of individuals with cardiovascular disease, i.e. coronary artery disease and chronic heart failure patients, but also in patients with congenital or valvular heart disease. Based on the current literature, and if sufficient evidence is available, recommendations from the European Association on Cardiovascular Prevention and Rehabilitation are formulated regarding frequency, intensity, time and type of PA, and safety aspects during exercise inpatients with cardiovascular disease. This paper is the third in a series of three papers, all devoted to the same theme: the importance of the exercise characteristics in the management of cardiovascular health. Part I is directed to the general population and Part II to individuals with cardiovascular risk factors. In general, PA recommendations and exercise training programmes for patients with coronary artery disease or chronic heart failure need to be tailored to the individual's exercise capacity and risk profile, with the aim to reach and maintain the individually highest fitness level possible and to perform endurance exercise training 30–60 min daily (3–5 days per week) in combination with resistance training 2–3 times a week. Because of the frequently reported dose–response relationship between training effect and exercise intensity, one should seek sufficiently high training intensities, although more scientific evidence on effect sizes and safety is warranted. At present, there is insufficient data to give more specific recommendations on type, dosage, and intensity of exercise in some other cardiovascular diseases, such as congenital heart disease, valve disease, cardiomyopathies, channelopathies, and patients with implanted devices.

Low-Carbohydrate-High-Fat Diet: Can it Help Exercise Performance?

PubMed Central

Borer, Katarina; Lin, Po-Ju

2017-01-01

Abstract Low-carbohydrate-high-fat (LCHF) diets have been used as a means of weight loss and control of symptoms in several clinical conditions. There is emerging evidence that the metabolic changes induced by LCHF diets enhance endurance performance. The aims of this review are to examine the evidence of LCHF diets in improving various aspects of athletic performance. Long-term LCHF dietary intake may help control body weight and fat mass while maintaining lean body mass in athletes in weight-sensitive sports. LCHF-adapted endurance athletes can reach the maximal fat oxidation rate of approximately 1.5 g/min, with a lower carbohydrate oxidation rate and similar muscle glycogen content and a resynthesis rate compared to their counterparts consuming high-carbohydrate-low-fat (HCLF) diets. The elevated fat oxidation rate and glycogen sparing effect may improve performance in ultra-endurance events. These metabolic changes may also prevent the decline in performance in later stages of repeated high-intensity movements, in which the aerobic metabolism becomes more important. However, elevated blood concentrations of non-esterified fatty acids and ammonia during exercise after LCHF diets may lead to early development of central fatigue. It appears that at least several months of adaptation to a LCHF diet are required for the metabolic changes and restoration of muscle glycogen to occur. Further investigations on LCHF diets are needed regarding (1) performance after weight loss in weight-categorized sports; (2) repeated high-intensity exercise performance; (3) development of central fatigue during endurance events; (4) perceptual-motor performance during prolonged intermittent sports; and (5) ideal dietary fatty acid compositions. PMID:28469746

Low-Carbohydrate-High-Fat Diet: Can it Help Exercise Performance?

PubMed

Chang, Chen-Kang; Borer, Katarina; Lin, Po-Ju

2017-02-01

Low-carbohydrate-high-fat (LCHF) diets have been used as a means of weight loss and control of symptoms in several clinical conditions. There is emerging evidence that the metabolic changes induced by LCHF diets enhance endurance performance. The aims of this review are to examine the evidence of LCHF diets in improving various aspects of athletic performance. Long-term LCHF dietary intake may help control body weight and fat mass while maintaining lean body mass in athletes in weight-sensitive sports. LCHF-adapted endurance athletes can reach the maximal fat oxidation rate of approximately 1.5 g/min, with a lower carbohydrate oxidation rate and similar muscle glycogen content and a resynthesis rate compared to their counterparts consuming high-carbohydrate-low-fat (HCLF) diets. The elevated fat oxidation rate and glycogen sparing effect may improve performance in ultra-endurance events. These metabolic changes may also prevent the decline in performance in later stages of repeated high-intensity movements, in which the aerobic metabolism becomes more important. However, elevated blood concentrations of non-esterified fatty acids and ammonia during exercise after LCHF diets may lead to early development of central fatigue. It appears that at least several months of adaptation to a LCHF diet are required for the metabolic changes and restoration of muscle glycogen to occur. Further investigations on LCHF diets are needed regarding (1) performance after weight loss in weight-categorized sports; (2) repeated high-intensity exercise performance; (3) development of central fatigue during endurance events; (4) perceptual-motor performance during prolonged intermittent sports; and (5) ideal dietary fatty acid compositions.

Can HRV be used to evaluate training load in constant load exercises?

PubMed

Kaikkonen, Piia; Hynynen, Esa; Mann, Theresa; Rusko, Heikki; Nummela, Ari

2010-02-01

The overload principle of training states that training load (TL) must be sufficient to threaten the homeostasis of cells, tissues, organs, and/or body. However, there is no "golden standard" for TL measurement. The aim of this study was to examine if any post-exercise heart rate variability (HRV) indices could be used to evaluate TL in exercises with different intensities and durations. Thirteen endurance-trained males (35 +/- 5 year) performed MODE (moderate intensity, 3 km at 60% of the maximal velocity of the graded maximal test (vVO(2max))), HI (high intensity, 3 km at 85% vVO(2max)), and PRO (prolonged, 14 km at 60% vVO(2max)) exercises on a treadmill. HRV was analyzed with short-time Fourier-transform method during rest, exercise, and 15-min recovery. Rating of perceived exertion (RPE), blood lactate (BLa), and HFP(120) (mean of 0-120 s post-exercise) described TL of these exercises similarly, being different for HI (P < 0.05) and PRO (P < 0.05) when compared with MODE. RPE and BLa also correlated negatively with HFP(120) (r = -0.604, -0.401), LFP(120) (-0.634, -0.601), and TP(120) (-0.691, -0.569). HRV recovery dynamics were similar after each exercise, but the level of HRV was lower after HI than MODE. Increased intensity or duration of exercise decreased immediate HRV recovery, suggesting that post-exercise HRV may enable an objective evaluation of TL in field conditions. The first 2-min recovery seems to give enough information on HRV recovery for evaluating TL.

High- and low-intensity exercise do not improve cognitive function after stroke: A randomized controlled trial.

PubMed

Tang, Ada; Eng, Janice J; Krassioukov, Andrei V; Tsang, Teresa S M; Liu-Ambrose, Teresa

2016-11-11

To determine the effects of high versus low-intensity exercise on cognitive function following stroke. Secondary analysis from a randomized controlled trial with blinded assessors. 50-80 years old, living in the community, > 1 year post-stroke. Participants were randomized into a high-intensity Aerobic Exercise or low-intensity non-aerobic Balance/Flexibility program. Both programs were 6 months long, with 3 60-min sessions/week. Verbal item and working memory, selective attention and conflict resolution, set shifting were assessed before and after the program. Forty-seven participants completed the study (22/25 in Aerobic Exercise group, 25/25 in Balance/Flexibility group). There was an improvement in verbal item memory in both groups (time effect p = 0.04), and no between-group differences in improvement in the other outcomes (p > 0.27). There was no association between pre-exercise cognitive function and post-exercise improvement. In contrast to a small body of previous research suggesting positive benefits of exercise on cognition post-stroke, the current study found that 6 months of high or low intensity exercise was not effective in improving cognitive function, specifically executive functions. Further research in this area is warranted to establish the effectiveness of post-stroke exercise programs on cognition, and examine the mechanisms that underlie these changes.

Intra-dialytic training accelerates oxygen uptake kinetics in hemodialysis patients.

PubMed

Reboredo, Maycon M; Neder, J Alberto; Pinheiro, Bruno V; Henrique, Diane Mn; Lovisi, Julio Cm; Paula, Rogério B

2015-07-01

End-stage renal disease is associated with several hemodynamic and peripheral muscle abnormalities that could slow the rate of change in oxygen uptake ([Formula: see text]O2) at the onset and at the end of exercise. This study was performed to determine whether an intra-dialytic aerobic training program would speed [Formula: see text]O2 kinetics at the transition to and from moderate and high-intensity exercise. This study was a randomized controlled trial. Twenty-four patients with end-stage renal disease (14 females; 47.0 ± 11.9 years) were randomly assigned to either 12-week cycle ergometer-based training at moderate exertion or a similar control period. At initial and final evaluations, patients underwent 6 min moderate and high-intensity tests to exercise intolerance (Tlim). Training improved Tlim by ∼90% (median (inter-quartile range) = 232 (59) s to 445 (451) s, p < 0.05); in contrast, Tlim decreased by ∼30% in controls (291 (134) s to 202 (131) s). [Formula: see text]O2 kinetics at the onset of moderate-intensity exercise were significantly accelerated with training leading to lower oxygen (O2) deficit (mean ± standard deviation (SD) = 3.2 ± 1.3 l vs 2.3 ± 1.2 l). Similar positive effects were found at the high-intensity test either at the onset of, or recovery from, exercise (p < 0.05). "Excess" [Formula: see text]O2 at the high-intensity test was also lessened with training. Changes in Tlim correlated with faster [Formula: see text]O2 kinetics and lower "excess" [Formula: see text]O2 (Spearman's ρ = -0.56 and -0.75, respectively; p < 0.01). A symptom-targeted intra-dialytic training program improved sub-maximal aerobic metabolism and endurance exercise capacity. [Formula: see text]O2 kinetics are valuable in providing relatively effort-independent information on the efficacy of exercise interventions in this patient population. © The European Society of Cardiology 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Effects of exercise on functional aerobic capacity in adults with fibromyalgia syndrome: A systematic review of randomized controlled trials.

PubMed

García-Hermoso, Antonio; Saavedra, Jose M; Escalante, Yolanda

2015-01-01

Patients with fibromyalgia present a reduced capacity of upper and lower limb physical performance and affect their independence in performing everyday activities. The purpose of the present systematic review was to summarize evidence for the effectiveness and structure of exercise programs on functional aerobic capacity in patients with fibromyalgia syndrome. Keyword searches were made of seven databases. The systematic review was limited to English language studies of people with FM that evaluated the effects of exercise programs on functional aerobic capacity (6-minute walk test). The criteria for inclusion were satisfied by 12 randomized controlled trial (RCT) studies. The main cumulative evidence indicates that the programs based on aerobic exercise alone and on aquatic exercises have large (effect size = 0.85) and moderate (effect size = 0.44) effects. Aerobic and aquatic exercises at the proper intensity favour the increased functional aerobic capacity of fibromyalgia patients; however, most works do not adequately detail the intensity of the exercises. Moderate intensity exercise (aerobic and aquatic exercise) performed at least two times per week and 30-60 minutes a day is effective for increasing functional aerobic capacity, favouring the daily activities of daily living in this population.

The effect of midday moderate-intensity exercise on postexercise hypoglycemia risk in individuals with type 1 diabetes.

PubMed

Davey, Raymond J; Howe, Warwick; Paramalingam, Nirubasini; Ferreira, Luis D; Davis, Elizabeth A; Fournier, Paul A; Jones, Timothy W

2013-07-01

Exercise increases the risk of hypoglycemia in type 1 diabetes. Recently we reported a biphasic increase in glucose requirements to maintain euglycemia after late-afternoon exercise, suggesting a unique pattern of delayed risk for nocturnal hypoglycemia. This study examined whether this pattern of glucose requirements occurs if exercise is performed earlier in the day. Ten adolescents with type 1 diabetes underwent a hyperinsulinemic euglycemic glucose clamp on 2 different occasions during which they either rested or performed 45 minutes of moderate-intensity exercise at midday. Glucose was infused to maintain euglycemia for 17 hours after exercise. The glucose infusion rate (GIR) to maintain euglycemia, glucose rates of appearance and disappearance, and levels of counterregulatory hormones were compared between conditions. GIRs to maintain euglycemia were not significantly different between groups at baseline (9.8 ± 1.4 and 9.5 ± 1.6 g/h before the exercise and rest conditions, respectively) and did not change in the rest condition throughout the study. In contrast, GIR increased more than 3-fold during exercise (from 9.8 ± 1.4 to 30.6 ± 4.7 g/h), fell within the first hour of recovery, but remained elevated until 11 hours after exercise before returning to baseline levels. The pattern of glucose requirements to maintain euglycemia in response to moderate-intensity exercise performed at midday suggests that the risk of exercise-mediated hypoglycemia increases during and for several hours after moderate-intensity exercise, with no evidence of a biphasic pattern of postexercise risk of hypoglycemia.

Integrated physiological mechanisms of exercise performance, adaptation, and maladaptation to heat stress.

PubMed

Sawka, Michael N; Leon, Lisa R; Montain, Scott J; Sonna, Larry A

2011-10-01

This article emphasizes significant recent advances regarding heat stress and its impact on exercise performance, adaptations, fluid electrolyte imbalances, and pathophysiology. During exercise-heat stress, the physiological burden of supporting high skin blood flow and high sweating rates can impose considerable cardiovascular strain and initiate a cascade of pathophysiological events leading to heat stroke. We examine the association between heat stress, particularly high skin temperature, on diminishing cardiovascular/aerobic reserves as well as increasing relative intensity and perceptual cues that degrade aerobic exercise performance. We discuss novel systemic (heat acclimation) and cellular (acquired thermal tolerance) adaptations that improve performance in hot and temperate environments and protect organs from heat stroke as well as other dissimilar stresses. We delineate how heat stroke evolves from gut underperfusion/ischemia causing endotoxin release or the release of mitochondrial DNA fragments in response to cell necrosis, to mediate a systemic inflammatory syndrome inducing coagulopathies, immune dysfunction, cytokine modulation, and multiorgan damage and failure. We discuss how an inflammatory response that induces simultaneous fever and/or prior exposure to a pathogen (e.g., viral infection) that deactivates molecular protective mechanisms interacts synergistically with the hyperthermia of exercise to perhaps explain heat stroke cases reported in low-risk populations performing routine activities. Importantly, we question the "traditional" notion that high core temperature is the critical mediator of exercise performance degradation and heat stroke. Published 2011. This article is a U.S. Government work and is in the public domain in the USA.

Rowers' Self-Reported Behaviors, Attitudes, and Safety Concerns Related to Exercise, Training, and Competition During Pregnancy.

PubMed

Franklin, Ashley; Mishtal, Joanna; Johnson, Teresa; Simms-Cendan, Judith

2017-08-01

Background The American College of Obstetrics and Gynecology notes that pregnant athletes require more supervision due to their involvement in strenuous training schedules throughout pregnancy. Currently, rowing is not mentioned in the guidelines despite its increasing popularity, high cardiovascular demands, and risk for abdominal trauma. Methods This study aimed to elicit information from competitive female rowers regarding exercise, training, and competition during pregnancy. We administered a survey consisting of 122 items to female Masters rowers in the United States, aged 21 to 49 years, from June to December 2013. Results A total of 224 recreational and elite rowers met the inclusion criteria. Pregnant rowers self-reported high levels of exercise engagement: 85.2% (n/N = 98/115) exercised during any past pregnancy; exercise adherence decreased throughout pregnancy with 51.3%, 42.4%, and 15.7% meeting and/or exceeding national guidelines during the first, second, and third trimesters, respectively. Rowers were significantly (p < 0.001) more likely to state that an activity at a specified intensity and trimester was unsafe if they were younger, had less rowing experience, or were nulliparous. Decreased perceived rowing safety was associated with on-water training, higher intensity exercise, competition, and increasing gestational age. Primary safety concerns were the risk of oar-induced abdominal trauma and physiological effects due to high intensities required by the sport. Novel barriers to exercise in pregnancy included guilt towards the team and a mental barrier due to decreased performance. Healthcare providers are the number one information source for rowers regarding exercise during pregnancy. Conclusion Pregnant rowers are a relevant obstetrics population and have barriers and sport-specific safety concerns not previously identified in the literature. Rowers consider exercising in pregnancy to be important and struggle to meet exercise guidelines like the general population, indicating the need for healthcare providers to provide prenatal and antenatal education and interventions to support exercise during pregnancy even amongst athletes.

Rowers’ Self-Reported Behaviors, Attitudes, and Safety Concerns Related to Exercise, Training, and Competition During Pregnancy

PubMed Central

Mishtal, Joanna; Johnson, Teresa; Simms-Cendan, Judith

2017-01-01

Background The American College of Obstetrics and Gynecology notes that pregnant athletes require more supervision due to their involvement in strenuous training schedules throughout pregnancy. Currently, rowing is not mentioned in the guidelines despite its increasing popularity, high cardiovascular demands, and risk for abdominal trauma. Methods This study aimed to elicit information from competitive female rowers regarding exercise, training, and competition during pregnancy. We administered a survey consisting of 122 items to female Masters rowers in the United States, aged 21 to 49 years, from June to December 2013. Results A total of 224 recreational and elite rowers met the inclusion criteria. Pregnant rowers self-reported high levels of exercise engagement: 85.2% (n/N = 98/115) exercised during any past pregnancy; exercise adherence decreased throughout pregnancy with 51.3%, 42.4%, and 15.7% meeting and/or exceeding national guidelines during the first, second, and third trimesters, respectively. Rowers were significantly (p < 0.001) more likely to state that an activity at a specified intensity and trimester was unsafe if they were younger, had less rowing experience, or were nulliparous. Decreased perceived rowing safety was associated with on-water training, higher intensity exercise, competition, and increasing gestational age. Primary safety concerns were the risk of oar-induced abdominal trauma and physiological effects due to high intensities required by the sport. Novel barriers to exercise in pregnancy included guilt towards the team and a mental barrier due to decreased performance. Healthcare providers are the number one information source for rowers regarding exercise during pregnancy. Conclusion Pregnant rowers are a relevant obstetrics population and have barriers and sport-specific safety concerns not previously identified in the literature. Rowers consider exercising in pregnancy to be important and struggle to meet exercise guidelines like the general population, indicating the need for healthcare providers to provide prenatal and antenatal education and interventions to support exercise during pregnancy even amongst athletes. PMID:28983443

Ratings of Perceived Exertion of ACSM Exercise Guidelines in Individuals Varying in Aerobic Fitness

ERIC Educational Resources Information Center

Kaufman, Christopher; Berg, Kris; Noble, John; Thomas, James

2006-01-01

The physiological responses of high (HF) and low fit (LF) individuals at given perceived exercise intensities were compared to ranges provided by the American College of Sports Medicine (ACSM). Participants were 7 LF and 8 HF men between the ages of 22 and 26 years. All participants performed a maximum oxygen uptake and lactate threshold test and…

Study protocol for the FITR Heart Study: Feasibility, safety, adherence, and efficacy of high intensity interval training in a hospital-initiated rehabilitation program for coronary heart disease.

PubMed

Taylor, Jenna; Keating, Shelley E; Leveritt, Michael D; Holland, David J; Gomersall, Sjaan R; Coombes, Jeff S

2017-12-01

For decades, moderate intensity continuous training (MICT) has been the cornerstone of exercise prescription for cardiac rehabilitation (CR). High intensity interval training (HIIT) is now recognized in CR exercise guidelines as an appropriate and efficient modality for improving cardiorespiratory fitness, a strong predictor of mortality. However, the clinical application of HIIT in a real world CR setting, in terms of feasibility, safety, and long-term adherence, needs further investigation to address ongoing reservations. Furthermore, studies using objective measures of exercise intensity (such as heart rate; HR) have produced variable outcomes. Therefore we propose investigating the use of subjective measures (such as rating of perceived exertion (RPE)) for prescribing exercise intensity. One hundred adults with coronary artery disease (CAD) attending a hospital-initiated CR program will be randomized to 1) HIIT: 4 × 4 min high intensity intervals at 15-18 RPE interspersed with 3-min active recovery periods or 2) MICT: usual care exercise including 40 min continuous exercise at a moderate intensity corresponding to 11-13 RPE. Primary outcome is change in exercise capacity (peak VO 2 ) following 4 weeks of exercise training. Secondary outcome measures are: feasibility, safety, exercise adherence, body composition, vascular function, inflammatory markers, intrahepatic lipid, energy intake, and dietary behavior over 12-months; and visceral adipose tissue (VAT) following 12 weeks of exercise training. This study aims to address the ongoing concerns regarding the practicality and safety of HIIT in CR programs. We anticipate study findings will lead to the development of a standardized protocol to facilitate CR programs to incorporate HIIT as a standard exercise option for appropriate patients.

Oxidative stress does not influence local sweat rate during high-intensity exercise.

PubMed

Meade, Robert D; Fujii, Naoto; Poirier, Martin P; Boulay, Pierre; Sigal, Ronald J; Kenny, Glen P

2018-02-01

What is the central question of this study? We evaluated whether oxidative stress attenuates the contribution of nitric oxide to sweating during high-intensity exercise. What is the main finding and its importance? In contrast to our previous report of an oxidative stress-mediated reduction in nitric oxide-dependent cutaneous vasodilatation in this cohort during intense exercise, we demonstrated no influence of local ascorbate administration on the sweating response during moderate- (∼51% peak oxygen uptake) or high-intensity exercise (∼72% peak oxygen uptake). These new findings provide important mechanistic insight into how exercise-induced oxidative stress impacts sudomotor activity. Nitric oxide (NO)-dependent sweating is diminished during high- but not moderate-intensity exercise. We evaluated whether this impairment stems from increased oxidative stress during high-intensity exercise. On two separate days, 11 young (24 ± 4 years) men cycled in the heat (35°C) at a moderate [500 W; 52 ± 6% peak oxygen uptake (V̇O2 peak )] or high (700 W; 71 ± 5% V̇O2 peak ) rate of metabolic heat production. Each session included two 30 min exercise bouts separated by a 20 min recovery period. Local sweat rate was monitored at four forearm skin sites continuously perfused via intradermal microdialysis with the following: (i) lactated Ringer solution (Control); (ii) 10 mm ascorbate (Ascorbate; non-selective antioxidant); (iii) 10 mm N G -nitro-l-arginine methyl ester (l-NAME; NO synthase inhibitor); or (iv) 10 mm ascorbate plus 10 mm l-NAME (Ascorbate + l-NAME). During moderate exercise, sweat rate was attenuated at the l-NAME and Ascorbate + l-NAME sites (both ∼1.0 mg min -1  cm -2 ; all P < 0.05) but not at the Ascorbate site (∼1.1 mg min -1  cm -2 ; both P ≥ 0.28) in comparison to the Control site (∼1.1 mg min -1  cm -2 ). However, no differences were observed between treatment sites (∼1.4 mg min -1  cm -2 ; P = 0.75) during high-intensity exercise. We conclude that diminished NO-dependent sweating during intense exercise occurs independent of oxidative stress. © 2017 The Authors. Experimental Physiology © 2017 The Physiological Society.

Social physique anxiety and physical activity behaviour of male and female exercisers.

PubMed

Portman, Robert M; Bradbury, Jane; Lewis, Kiara

2018-03-01

Despite females consistently reporting greater social physique anxiety (SPA), previous literature has yet to demonstrate whether SPA gender differences are linked to the way males and females perform physical activity. This study investigated an association between SPA and physical activity frequency, history of exercise, and physical activity intensity. Participants were represented by currently active users (N = 33 males; N = 31 females) of an on-campus university-run gym and completed a background physical activity questionnaire and the nine-item Social Physique Anxiety Scale. Participants also performed an exercise session at a self-selected level of exertion, with the intensity of each session measured via heart rate monitor. SPA was not associated with physical activity frequency, history of exercise (length of gym membership), or intensity for male and female exercisers. With respect to male participants, females reported higher SPA and a preference for performing higher intensity physical activity. Females and males also indicated a preference for performing aerobic and anaerobic physical activity respectively. Our findings suggest the experience of SPA does not deter body-conscious individuals from the performance of regular physical activity. Findings also suggest the discrepancy in male and female SPA is not linked to differences in the way physical activity is performed.

[Acute physical exercise increases homocysteine concentrations in young trained male subjects].

PubMed

Maroto-Sánchez, Beatriz; Valtueña, Jara; Albers, Ulrike; Benito, Pedro J; González-Gross, Marcela

2013-01-01

High levels of homocysteine (Hcy) have been identified as a cardiovascular risk factor. Regarding physical exercise, the results are contradictory. The aim of this study was to determine the influence of maximal intensity exercise and submaximal constant exercise on total serum homocysteine concentrations (tHcy) and other related parameters. Ten physically active male subjects (mean age: 23.51 ± 1.84), performed two treadmill tests, a maximal test and a stable submaximal test at an intensity of 65% of maximal oxygen uptake (VO2max). Serum concentrations of tHcy, Folate, Vitamin B12 and creatinine were analysed before and after each test. Significant increase in serum tHcy concentrations after the maximal (p < 0.05) and submaximal (p < 0.01) tests were observed. Folate and vitamin B12 concentrations also increased significantly after both tests (p < 0.05). Creatinine levels increased only after the maximal test (p < 0.001). A statistically significant inverse relationship was found between folate and tHcy concentrations (p < 0.05) at all the measurement points. THcy levels increased significantly after acute exercise in both maximum and submaximal intensity exercises. Copyright © AULA MEDICA EDICIONES 2013. Published by AULA MEDICA. All rights reserved.

Effect of set configuration on hemodynamics and cardiac autonomic modulation after high-intensity squat exercise.

PubMed

Iglesias-Soler, Eliseo; Boullosa, Daniel A; Carballeira, Eduardo; Sánchez-Otero, Tania; Mayo, Xian; Castro-Gacio, Xabier; Dopico, Xurxo

2015-07-01

The aim of this study was to compare the effect of two different high-intensity resistance exercise (RE) set configurations on the following: systolic blood pressure (SBP), rate pressure product (RPP), heart rate (HR) variability (HRV), and HR complexity (HRC). Ten well-trained males performed three parallel squat sets until failure (traditional training; TT) with the four repetitions maximum load (4RM), and a rest of 3 min between sets. Thereafter, participants performed a cluster training session (CT) of equated load but with resting time distributed between each repetition. Dependent variables were recorded before, during, and after RE. Mean SBP (25·7 versus 10·9% percentage increase; P = 0·016) and RPP (112·5 versus 69·9%; P = 0·01) were significantly higher in TT. The decrease in HRV after exercise and the drop of HRC during exercise were similar in CT and TT. Change of standard deviation of normal RR intervals after TT correlated with change in SBP (r = 0·803; P = 0·009) while the change of Sample Entropy during exercise correlated with the increment of RPP during CT (ρ = -0·667; P = 0·05). This study suggests that set configuration influences acute cardiovascular responses during RE. When intensity, volume and work-to-rest ratio are equated, CT is less demanding in terms of SBP and RPP. A greater hemodynamic response during exercise would be associated with a faster parasympathetic recovery. © 2014 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

The effects of high-intensity resistance exercise on the blood lipid profile and liver function in hypercholesterolemic hamsters.

PubMed

Frajacomo, Fernando Tadeu Trevisan; Demarzo, Marcelo Marcos Piva; Fernandes, Cleverson Rodrigues; Martinello, Flávia; Bachur, José Alexandre; Uyemura, Sérgio Akira; Perez, Sérgio Eduardo de Andrade; Garcia, Sérgio Britto

2012-06-01

It is well established that atherogenic dyslipidemia, characterized by high levels of triglycerides (TG), total cholesterol (TC), and low-density lipoprotein (LDL) cholesterol and low levels of high-density lipoprotein (HDL) cholesterol, constitutes important risk factors for cardiovascular disease. Regular exercise has been associated with a reduced risk for metabolic diseases. However, studies supporting the concept that resistance exercise is a modifier of blood lipid parameters are often contradictory. The aim of this study was to investigate the effects of high-intensity resistance exercise on the serum levels of TG, TC, HDL and non-HDL cholesterol, glucose, and the liver function enzymes alanine aminotransferase (ALT, EC 2.6.1.2) and aspartate aminotransferase (AST, EC 2.6.1.1) in golden Syrian hamsters (Mesocricetus auratus (Waterhouse, 1839)) fed a hypercholesterolemic diet. Sedentary groups (S) and exercise groups (E) were fed a standard diet (SS and ES) or a cholesterol-enriched diet (standard plus 1% cholesterol, SC and EC). Resistance exercise was performed by jumps in the water, carrying a load strapped to the chest, representing 10 maximum repetitions (10 RM, 30 s rest, five days per week for five weeks). Mean blood sample comparisons were made by ANOVA + Tukey or ANOVA + Kruskal-Wallis tests (p < 0.05) to compare parametric and nonparametric samples, respectively. There were no differences in blood lipids between the standard diet groups (SS and ES) (p > 0.05). However, the EC group increased the glucose, non-HDL, and TC levels in comparison with the ES group. Moreover, the EC group increased the TG levels versus the SC group (p < 0.05). In addition, the ALT levels were increased only by diet treatment. These findings indicated that high-intensity resistance exercise contributed to dyslipidemia in hamsters fed a hypercholesterolemic diet, whereas liver function enzymes did not differ in regards to the exercise protocol.

Adaptations to Speed Endurance Training in Highly Trained Soccer Players.

PubMed

Nyberg, Michael; Fiorenza, Matteo; Lund, Anders; Christensen, Magnus; Rømer, Tue; Piil, Peter; Hostrup, Morten; Christensen, Peter M; Holbek, Simon; Ravnholt, Thomas; Gunnarsson, Thomas P; Bangsbo, Jens

2016-07-01

The present study examined whether a period of additional speed endurance training would improve intense intermittent exercise performance in highly trained soccer players during the season and whether the training changed aerobic metabolism and the level of oxidative enzymes in type I and type II muscle fibers. During the last 9 wk of the season, 13 semiprofessional soccer players performed additional speed endurance training sessions consisting of two to three sets of 8-10 repetitions of 30-m sprints with 10 s of passive recovery (SET). Before and after SET, subjects completed a double-step exercise protocol that included transitions from standing to moderate-intensity running (~75% HRmax), followed by transitions from moderate- to high-intensity running (~90% HRmax) in which pulmonary oxygen uptake (V˙O2) was determined. In addition, the yo-yo intermittent recovery test level 1 was performed, and a muscle biopsy was obtained at rest. The yo-yo intermittent recovery test level 1 performance was 11.6% ± 6.4% (mean ± SD) better (2803 ± 330 vs 3127 ± 383 m, P < 0.05) after SET compared with before SET. In the transition from standing to moderate-intensity running, phase II pulmonary V˙O2 kinetics was 11.4% ± 16.5% faster (P < 0.05), and the running economy at this intensity was 2.3% ± 3.0% better (P < 0.05). These improvements were apparent despite the content of muscle proteins regulating oxidative metabolism (3-hydroxyacyl CoA dehydrogenase, COX IV, and OXPHOS), and capillarization was reduced (P < 0.05). The content of 3-hydroxyacyl CoA dehydrogenase and citrate synthase in type I and type II fibers did not change. In highly trained soccer players, additional speed endurance training is associated with an improved ability to perform repeated high-intensity work. To what extent the training-induced changes in V˙O2 kinetics and mechanical efficiency in type I fibers caused the improvement in performance warrants further investigation.

When 'just doing it' is not enough: assessing the fidelity of player performance of an injury prevention exercise program.

PubMed

Fortington, Lauren V; Donaldson, Alex; Lathlean, Tim; Young, Warren B; Gabbe, Belinda J; Lloyd, David; Finch, Caroline F

2015-05-01

To obtain benefits from sports injury prevention programs, players are instructed to perform the exercises as prescribed. We developed an observational checklist to measure the quality of exercise performance by players participating in FootyFirst, a coach-led, exercise-based, lower-limb injury prevention program in community Australian Football (AF). Observational. The essential performance criteria for each FootyFirst exercise were described in terms of the technique, volume and intensity required to perform each exercise. An observational checklist was developed to evaluate each criterion through direct visual observation of players at training. The checklist was trialled by two independent raters who observed the same 70 players completing the exercises at eight clubs. Agreement between observers was assessed by Kappa-statistics. Exercise fidelity was defined as the proportion of observed players who performed all aspects of their exercises correctly. The raters agreed on 61/70 observations (87%) (Kappa=0.72, 95% CI: 0.55; 0.89). Of the observations with agreed ratings, 41 (67%) players were judged as performing the exercises as prescribed. The observational checklist demonstrated high inter-rater reliability. Many players observed did not perform the exercises as prescribed, raising concern as to whether they would be receiving anticipated program benefits. Where quality of exercise performance is important, evaluation and reporting of program fidelity should include direct observations of participants. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

The relationship between aerobic fitness and recovery from high-intensity exercise in infantry soldiers.

PubMed

Hoffman, J R

1997-07-01

The relationship between aerobic fitness and recovery from high-intensity exercise was examined in 197 infantry soldiers. Aerobic fitness was determined by a maximal-effort, 2,000-m run (RUN). High-intensity exercise consisted of three bouts of a continuous 140-m sprint with several changes of direction. A 2-minute passive rest separated each sprint. A fatigue index was developed by dividing the mean time of the three sprints by the fastest time. Times for the RUN were converted into standardized T scores and separated into five groups (group 1 had the slowest run time and group 5 had the fastest run time). Significant differences in the fatigue index were seen between group 1 (4.9 +/- 2.4%) and groups 3 (2.6 +/- 1.7%), 4 (2.3 +/- 1.6%), and 5 (2.3 +/- 1.3%). It appears that recovery from high-intensity exercise is improved at higher levels of aerobic fitness (faster time for the RUN). However, as the level of aerobic fitness improves above the population mean, no further benefit in the recovery rate from high-intensity exercise is apparent.

Effects of Exercise Intervention on Preventing Letrozole-Exposed Rats From Polycystic Ovary Syndrome.

PubMed

Cao, Si-Fan; Hu, Wen-Long; Wu, Min-Min; Jiang, Li-Yan

2017-03-01

Polycystic ovary syndrome (PCOS) is a prevalent endocrinological disorder in reproductive-age women and is often associated with a metabolic syndrome. To investigate whether exercise intervention promotes PCOS prevention, a rat model was used. Polycystic ovary syndrome was induced by letrozole administration, and animals presented with obesity, sex hormone disorder, no ovulation, large cystic follicles, and increasing fasting insulin (FINS) and leptin levels. The intervention was set at 3 different intensities of swimming exercise: low (0.5 h/d), moderate (1 h/d), and high (2 h/d), and compared with a PCOS model group (letrozole administration without exercise intervention) and a control group. The exercise intervention in the low-intensity group did not produce changes in obesity, testosterone, progesterone (P), and follicle-stimulating hormone (FSH) levels. Moderate-intensity exercise reduced body weight, retained ovulation, and P levels were increased but remained lower than those in the control group. The FSH levels were significantly higher, and FINS and leptin levels were lower than in the model group ( P < 0.05) but not in the control group. The high-intensity group demonstrated the greatest effect of PCOS prevention. Testosterone, luteinizing hormone, FINS, and leptin levels were significantly lower in the high-intensity group, and FSH and P levels were higher compared with the model group. These results suggest that high-intensity exercise intervention can effectively prevent PCOS development.

Effect of aqua exercise on recovery of lower limb muscles after downhill running.

PubMed

Takahashi, Junichiro; Ishihara, Keiji; Aoki, Junichiro

2006-08-01

The aim of the present study was to examine how the recovery of physiological functioning of the leg muscles after high-intensity eccentric exercise such as downhill running could be promoted by aqua exercise for a period until the damaged muscle had recovered almost completely. Ten male long-distance runners were divided equally into an aqua exercise group and a control group. From the first day (Day 0) to the fourth day (Day 3), the participants completed a questionnaire on muscle soreness, and serum creatine kinase activity, muscle power, flexibility, whole-body reaction time and muscle stiffness were measured. After measurements on Day 0, the participants performed downhill running (three 5 min runs with a 5 min rest interval at -10%, 335.7 +/- 6.1 m . min-1). The aqua exercise group performed walking, jogging and jumping in water on three successive days following the downhill running on Day 0 for 30 min each day. Muscle power was reduced on Day 1 in the control group (P < 0.05). Muscle soreness in the calf on Day 3 was greater in the control group than that in the aqua exercise group (P < 0.05). In the aqua exercise group, muscle stiffness in the calf was less than that in the control group over 4 days (time main effect: P < 0.05; group x time interaction: P < 0.05). We conclude that aqua exercise promoted physiological functioning of the muscles in the legs after high-intensity downhill running for a period until the damaged muscles had recovered almost completely.

Acute Physiological Responses to Short- and Long-Stage High-Intensity Interval Exercise in Cardiac Rehabilitation: A Pilot Study

PubMed Central

Tschakert, Gerhard; Kroepfl, Julia M.; Mueller, Alexander; Harpf, Hanns; Harpf, Leonhard; Traninger, Heimo; Wallner-Liebmann, Sandra; Stojakovic, Tatjana; Scharnagl, Hubert; Meinitzer, Andreas; Pichlhoefer, Patriz; Hofmann, Peter

2016-01-01

Despite described benefits of aerobic high-intensity interval exercise (HIIE), the acute responses during different HIIE modes and associated health risks have only been sparsely discovered in heart disease patients. Therefore, the aim of this study was to investigate the acute responses for physiological parameters, cardiovascular and inflammatory biomarkers, and catecholamines yielded by two different aerobic HIIE protocols compared to continuous exercise (CE) in phase III cardiac rehabilitation. Eight cardiac patients (7 with coronary heart disease, 1 with myocarditis; 7 males, 1 female; age: 63.0 ± 9.4 years; height: 1.74 ± 0.05 m; weight: 83.6 ± 8.7 kg), all but one treated with ß-blocking agents, performed a maximal symptom-limited incremental exercise test (IET) and three different exercise tests matched for mean load (Pmean) and total duration: 1) short HIIE with a peak workload duration (tpeak) of 20 s and a peak workload (Ppeak) equal to the maximum power output (Pmax) from IET; 2) long HIIE with a tpeak of 4 min, Ppeak was corresponding to the power output at 85 % of maximal heart rate (HRmax) from IET; 3) CE with a target workload equal to Pmean of both HIIE modes. Acute metabolic and peak cardiorespiratory responses were significantly higher during long HIIE compared to short HIIE and CE (p < 0.05) except HRpeak which tended to be higher in long HIIE than in short HIIE (p = 0.08). Between short HIIE and CE, no significant difference was found for any parameter. Acute responses of cardiovascular and inflammatory biomarkers and catecholamines didn’t show any significant difference between tests (p > 0.05). All health-related variables remained in a normal range in any test except NT-proBNP, which was already elevated at baseline. Despite a high Ppeak particularly in short HIIE, both HIIE modes were as safe and as well tolerated as moderate CE in cardiac patients by using our methodological approach. Key points High-intensity interval exercise (HIIE) with short peak workload durations (tpeak) induce a lower acute metabolic and peak cardiorespiratory response compared to intervals with long tpeak despite higher peak workload intensities and identical mean load. No significant difference for any physiological parameter was found between short HIIE and CE. Between short HIIE, long HIIE, and CE, no significant difference was found in the increase (or decrease, respectively,) of health related markers such as cardiovascular biomarkers, catecholamines, or inflammatory parameters during exercise. During all exercise modes, all risk markers remained in a normal range except for NT-proBNP which was, however, already elevated at baseline. Short HIIE, long HIIE, and CE were safely performed by patients with CHD or myocarditis in cardiac rehabilitation by using our methodological approach to exercise prescription. This approach included the prescription of exercise intensities with respect to LTP1, LTP2, and Pmax as well as a conscious setting of Pmean at a moderate level (80 % of PLTP2). Importantly, all exercise modes were matched for Pmean and exercise duration in order to enable a comparison of the three protocols. PMID:26957930

Inter-individual Differences in Exercise-Induced Spatial Working Memory Improvement: A Near-Infrared Spectroscopy Study.

PubMed

Yamazaki, Yudai; Sato, Daisuke; Yamashiro, Koya; Tsubaki, Atsuhiro; Yamaguchi, Yui; Takehara, Nana; Maruyama, Atsuo

2017-01-01

Acute aerobic exercise at a mild intensity improves cognitive function. However, the response to exercise exhibits inter-individual differences, and the mechanisms underlying these differences remain unclear. The objective of this study was to determine potential factors in the brain that underlie differential responses to exercise in terms of cognitive improvement using functional near-infrared spectroscopy. Fourteen healthy subjects participated in these experiments. Participants performed a low intensity cycling exercise at 30% maximal oxygen uptake (VO 2peak ) for 10 min and performed a spatial memory task before and after exercising (5 and 30 min). The spatial memory task comprised two levels of difficulty (low: 1-dot EXERCISE, high: 3-dot EXERCISE). Cortical oxy-hemoglobin (O 2 Hb) levels were recorded using near-infrared spectroscopy during both the exercise and the spatial memory task phases. Regions of interests included the dorsolateral prefrontal cortex (DLPFC), ventrolateral prefrontal cortex (VLPFC), and frontopolar area (FPA). The participants were divided into two groups depending on whether they were responders (improved task reaction time) or non-responders (no improvement). Subsequently, we analyzed the group characteristics and differences in the change in O 2 Hb levels during exercise and spatial working memory tasks. Acute mild exercise significantly improved mean reaction times in the 1-dot memory task but not in the 3-dot task across the participants. In the 1-dot EXERCISE, 10 subjects were responders and four subjects were non-responders, whereas in the 3-dot EXERCISE, seven subjects were non-responders. In responders, during exercise, we found higher O 2 Hb levels in the right VLPFC response for the 1-dot memory task. Acute mild exercise caused inter-individual differences in spatial memory improvement, which were associated with changes in O 2 Hb activity in the prefrontal area during the exercise phase but not during the actual spatial memory task. Therefore, individuals who respond with higher reactivity to mild intensity exercise in the VLPFC might obtain larger spatial working memory improvements following exercise than non-responders.

The Metabolic Cost of a High Intensity Exercise Program During Bed Rest

NASA Technical Reports Server (NTRS)

Hackney, Kyle; Everett, Meghan; Guined, Jamie; Cunningham, Daid

2012-01-01

Background: Given that disuse-related skeletal muscle atrophy may be exacerbated by an imbalance between energy intake and output, the amount of energy required to complete exercise countermeasures is an important consideration in the well being of subject health during bed rest and spaceflight. Objective: To evaluate the energy cost of a high intensity exercise program performed during short duration bed rest. Methods: 9 subjects (8 male and 1 female; 34.5 +/- 8.2 years) underwent 14 days of bed rest and exercise countermeasures. Exercise energy expenditure and excess post exercise oxygen consumption (EPOC) were collected once in each of 5 different exercise protocols (30 second, 2 minute and 4 minute intervals, continuous aerobic and a variety of resistance exercises) during bed rest. Body mass, basal metabolic rate (BMR), upper and lower leg muscle, subcutaneous, and intramuscular adipose tissue (IMAT) volumes were assessed before and at the end of bed rest. Results: There were no significant differences in body mass (pre: 75.1 +/- 10.5 kg; post: 75.2 +/- 10.1 kg), BMR (pre: 1649 +/- 216 kcal; post: 1657 +/- 177 kcal), muscle subcutaneous, or IMAT volumes (Table 2) after 14 days of bed rest and exercise. Body mass was maintained with an average daily intake of 2710 +/- 262 kcal (36.2 +/- 2.1 kcal/kg/day), while average daily energy expenditure was 2579 +/-311 kcal (34.5 +/- 3.6 kcal/kg/day). Exercise energy expenditure was significantly greater as a result of continuous aerobic exercise than all other exercise protocols.

Effect of immediate and delayed cold water immersion after a high intensity exercise session on subsequent run performance.

PubMed

Brophy-Williams, Ned; Landers, Grant; Wallman, Karen

2011-01-01

The purpose of the study was to determine the effects of cold water immersion (CWI) performed immediately or 3 h after a high intensity interval exercise session (HIIS) on next-day exercise performance. Eight male athletes performed three HIIS at 90%VO2max velocity followed by either a passive recovery (CON), CWI performed immediately post-exercise (CWI(0)) or CWI performed 3 h post-exercise (CWI(3)). Recovery trials were performed in a counter balanced manner. Participants then returned 24 h later and completed a muscle soreness and a totally quality recovery perception (TQRP) questionnaire, which was then followed by the Yoyo Intermittent Recovery Test [level 1] (YRT). Venous blood samples were collected pre-HIIS and pre-YRT to determine C-Reactive Protein (CRP) levels. Significantly more shuttles were performed during the YRT following CWI(0) compared to the CON trial (p=0.017, ES = 0. 8), while differences between the CWI(3) and the CON trials approached significance (p = 0.058, ES = 0.5). Performance on the YRT between the CWI(0) and CWI(3) trials were similar (p = 0.147, ES = 0. 3). Qualitative analyses demonstrated a 98% and 92% likely beneficial effect of CWI(0) and CWI(3) on next day performance, compared to CON, respectively, while CWI(0) resulted in a 79% likely benefit when compared to CWI(3). CRP values were significantly lower pre-YRT, compared to baseline, following CWI(0) (p = 0.0.36) and CWI(3) (p = 0.045), but were similar for CON (p = 0.157). Muscle soreness scores were similar between trials (p = 1.10), while TQRP scores were significantly lower for CON compared to CWI(0) (p = 0.002 ) and CWI(3) (p = 0.024). Immediate CWI resulted in superior next-day YRT performance compared to CON, while delayed (3 h) CWI was also likely to be beneficial. Qualitative analyses suggested that CWI(0) resulted in better performance than CWI(3). These results are important for athletes who do not have immediate access to CWI following exercise. Key pointsPerformance of cold water immersion as a recovery procedure following exercise is better than performing no recovery procedureAthletes, coaches and sport trainers should implement cold water immersion post-exercise irrespective of the time of administration.Where possible, cold water immersion should be performed immediately post-exercise to gain maximal recovery benefits.

Atypical blood glucose response to continuous and interval exercise in a person with type 1 diabetes: a case report.

PubMed

Moser, Othmar; Tschakert, Gerhard; Mueller, Alexander; Groeschl, Werner; Pieber, Thomas R; Koehler, Gerd; Eckstein, Max L; Bracken, Richard M; Hofmann, Peter

2017-06-30

Therapy must be adapted for people with type 1 diabetes to avoid exercise-induced hypoglycemia caused by increased exercise-related glucose uptake into muscles. Therefore, to avoid hypoglycemia, the preexercise short-acting insulin dose must be reduced for safety reasons. We report a case of a man with long-lasting type 1 diabetes in whom no blood glucose decrease during different types of exercise with varying exercise intensities and modes was found, despite physiological hormone responses. A Caucasian man diagnosed with type 1 diabetes for 24 years performed three different continuous high-intensity interval cycle ergometer exercises as part of a clinical trial (ClinicalTrials.gov identifier NCT02075567). Intensities for both modes of exercises were set at 5% below and 5% above the first lactate turn point and 5% below the second lactate turn point. Short-acting insulin doses were reduced by 25%, 50%, and 75%, respectively. Measurements taken included blood glucose, blood lactate, gas exchange, heart rate, adrenaline, noradrenaline, cortisol, glucagon, and insulin-like growth factor-1. Unexpectedly, no significant blood glucose decreases were observed during all exercise sessions (start versus end, 12.97 ± 2.12 versus 12.61 ± 2.66 mmol L -1 , p = 0.259). All hormones showed the expected response, dependent on the different intensities and modes of exercises. People with type 1 diabetes typically experience a decrease in blood glucose levels, particularly during low- and moderate-intensity exercises. In our patient, we clearly found no decline in blood glucose, despite a normal hormone response and no history of any insulin insensitivity. This report indicates that there might be patients for whom the recommended preexercise therapy adaptation to avoid exercise-induced hypoglycemia needs to be questioned because this could increase the risk of severe hyperglycemia and ketosis.

A Single Bout of Moderate Aerobic Exercise Improves Motor Skill Acquisition.

PubMed

Statton, Matthew A; Encarnacion, Marysol; Celnik, Pablo; Bastian, Amy J

2015-01-01

Long-term exercise is associated with improved performance on a variety of cognitive tasks including attention, executive function, and long-term memory. Remarkably, recent studies have shown that even a single bout of aerobic exercise can lead to immediate improvements in declarative learning and memory, but less is known about the effect of exercise on motor learning. Here we sought to determine the effect of a single bout of moderate intensity aerobic exercise on motor skill learning. In experiment 1, we investigated the effect of moderate aerobic exercise on motor acquisition. 24 young, healthy adults performed a motor learning task either immediately after 30 minutes of moderate intensity running, after running followed by a long rest period, or after slow walking. Motor skill was assessed via a speed-accuracy tradeoff function to determine how exercise might differentially affect two distinct components of motor learning performance: movement speed and accuracy. In experiment 2, we investigated both acquisition and retention of motor skill across multiple days of training. 20 additional participants performed either a bout of running or slow walking immediately before motor learning on three consecutive days, and only motor learning (no exercise) on a fourth day. We found that moderate intensity running led to an immediate improvement in motor acquisition for both a single session and on multiple sessions across subsequent days, but had no effect on between-day retention. This effect was driven by improved movement accuracy, as opposed to speed. However, the benefit of exercise was dependent upon motor learning occurring immediately after exercise-resting for a period of one hour after exercise diminished the effect. These results demonstrate that moderate intensity exercise can prime the nervous system for the acquisition of new motor skills, and suggest that similar exercise protocols may be effective in improving the outcomes of movement rehabilitation programs.

The acute effects of graded physiological strain on soccer kicking performance: a randomized, controlled cross-over study.

PubMed

Radman, Ivan; Wessner, Barbara; Bachl, Norbert; Ruzic, Lana; Hackl, Markus; Prpic, Tomislav; Markovic, Goran

2016-02-01

The aim of the present study was to examine the acute effects of graded physiological strain on soccer kicking performance. Twenty-eight semi-professional soccer players completed both experimental and control procedure. The experimental protocol incorporated repeated shooting trials combined with a progressive discontinuous maximal shuttle-run intervention. The initial running velocity was 8 km/h and increasing for 1 km/h every 3 min until exhaustion. The control protocol comprised only eight subsequent shooting trials. The soccer-specific kicking accuracy (KA; average distance from the ball-entry point to the goal center), kicking velocity (KV), and kicking quality (KQ; kicking accuracy divided by the time elapsed from hitting the ball to the point of entry) were evaluated via reproducible and valid test over five individually determined exercise intensity zones. Compared with baseline or exercise at intensities below the second lactate threshold (LT2), physiological exertion above the LT2 (blood lactate > 4 mmol/L) resulted in meaningful decrease in KA (11-13%; p < 0.05), KV (3-4%; p < 0.05), and overall KQ (13-15%; p < 0.01). The light and moderate-intensity exercise below the LT2 had no significant effect on soccer kicking performance. The results suggest that high-intensity physiological exertion above the player's LT2 impairs soccer kicking performance. In contrast, light to moderate physiological stress appears to be neither harmful nor beneficial for kicking performance.

Serum levels of fatty acid binding protein 4 and fat metabolic markers in relation to catecholamines following exercise.

PubMed

Iso, Tatsuya; Sunaga, Hiroaki; Matsui, Hiroki; Kasama, Shu; Oshima, Naomi; Haruyama, Hikari; Furukawa, Nozomi; Nakajima, Kiyomi; Machida, Tetsuo; Murakami, Masami; Yokoyama, Tomoyuki; Kurabayashi, Masahiko

2017-11-01

Lipolysis is stimulated by activation of adrenergic inputs to adipose tissues. Our recent study showed that serum concentrations of fatty acid binding protein 4 (FABP4) are robustly elevated in patients with acute myocardial infarction and ventricular tachyarrhythmia, that display a marked activation of the sympathetic nervous system (SNS). However, it remains unknown whether circulating FABP4 concentrations are associated with exercise-induced SNS activation. Thirty one healthy volunteers underwent cardiopulmonary exercise testing on a cycle ergometer up to the workload levels below and above anaerobic threshold, low- and high-intensity exercise, respectively. Serial blood samplings were performed before and after exercise. High-intensity exercise significantly increased serum concentrations of FABP4 and catecholamines, and their concentrations declined fast thereafter in a similar fashion. These changes were accompanied by little, if any, changes in other metabolic markers. Regardless of adiposity, percent change from baseline to peak FABP4 levels (%FABP4) was comparable in all subjects. Stepwise regression analysis revealed that %FABP4 was highly correlated with that in norepinephrine. Our study reveals the significant correlation between circulating FABP4 and norepinephrine levels during exercise testing. Together with the fact that FABP4 is secreted from adipocytes via β-adrenergic-mediated lipolytic mechanisms, this study suggests FABP4 as a potential biomarker for adrenergic overdrive. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Post-plyometric exercise hypotension and heart rate in normotensive individuals: influence of exercise intensity.

PubMed

Arazi, Hamid; Asadi, Abbas; Rahimzadeh, Mehdi; Moradkhani, Amir-Hossein

2013-12-01

The purpose of this study was to compare the effects of high, moderate and low intensity plyometric exercise on the post-exercise systolic and diastolic blood pressure and heart rate responses. Ten healthy normotensive men (age, 21.1±0.9 years; height, 175.8±6 cm; and body mass, 69.1±13.6 kg) volunteered to participate in this study and were evaluated for three non-consecutive days in depth jump exercise from 20-cm box (low intensity [LI]), 40-cm box (moderate intensity [MI]) and 60-cm box (high intensity [HI]) for 5 sets of 20 repetitions. After each exercise session, systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were measured every 10 min for a period of 90 min. No significant differences were observed among post-exercise SBP, DBP and HR when the protocols (LI, MI and HI) were compared. The LI and HI protocols showed greater reduction in SBP at 40(th)-70(th) min of post-exercise (~9%), whereas the LI and MI protocols indicated greater reduction in DBP at 10(th)-50(th) min of post exercise (~10%). In addition, the change in the DBP for HI was not significant and the increases in the HR were similar for all intensities. It can be concluded that a plyometric exercise (PE) can reduce SBP and DBP post-exercise and therefore we can say that PE has significant effects for reducing BP and HR or post-exercise hypotension.

An Evidence-Based Approach To Exercise Prescriptions on ISS

NASA Technical Reports Server (NTRS)

Ploutz-Snyder, Lori

2009-01-01

This presentation describes current exercise countermeasures and exercise equipment for astronauts onboard the ISS. Additionally, a strategy for evaluating evidence supporting spaceflight exercise is described and a new exercise prescription is proposed. The current exercise regimen is not fully effective as the ISS exercise hardware does not allow for sufficient exercise intensity, the exercise prescription is adequate and crew members are noncompliant with the prescription. New ISS hardware is proposed, Advanced Resistance Exercise Device (ARED), which allows additional exercises, is instrumented for data acquisition and offers improved loading. The new T2 hardware offers a better harness and subject loading system, is instrumented to allow ground reaction force data, and offers improved speed. A strategy for developing a spaceflight exercise prescription is described and involves identifying exercise training programs that have been shown to maximize adaptive benefits of people exercising in both 0 and 1 g environments. Exercise intensity emerged as an important factor in maintaining physiologic adaptations in the spaceflight environment and interval training is suggested. New ISS exercise hardware should allow for exercise at intensities high enough to elicit adaptive responses. Additionally, new exercise prescriptions should incorporate higher intensity exercises and seek to optimize intensity, duration and frequency for greater efficiency.

Exercise intensity and the protection from postprandial vascular dysfunction in adolescents.

PubMed

Bond, B; Gates, P E; Jackman, S R; Corless, L M; Williams, C A; Barker, A R

2015-06-01

Acute exercise transiently improves endothelial function and protects the vasculature from the deleterious effects of a high-fat meal (HFM). We sought to identify whether this response is dependent on exercise intensity in adolescents. Twenty adolescents (10 male, 14.3 ± 0.3 yr) completed three 1-day trials: 1) rest (CON); 2) 8 × 1 min cycling at 90% peak power with 75 s recovery [high-intensity interval exercise (HIIE)]; and 3) cycling at 90% of the gas exchange threshold [moderate-intensity exercise (MIE)] 1 h before consuming a HFM (1.50 g/kg fat). Macrovascular and microvascular endothelial function was assessed before and immediately after exercise and 3 h after the HFM by flow-mediated dilation (FMD) and laser Doppler imaging [peak reactive hyperemia (PRH)]. FMD and PRH increased 1 h after HIIE [P < 0.001, effect size (ES) = 1.20 and P = 0.048, ES = 0.56] but were unchanged after MIE. FMD and PRH were attenuated 3 h after the HFM in CON (P < 0.001, ES = 1.78 and P = 0.02, ES = 0.59). FMD remained greater 3 h after the HFM in HIIE compared with MIE (P < 0.001, ES = 1.47) and CON (P < 0.001, ES = 2.54), and in MIE compared with CON (P < 0.001, ES = 1.40). Compared with CON, PRH was greater 3 h after the HFM in HIIE (P = 0.02, ES = 0.71) and MIE (P = 0.02, ES = 0.84), with no differences between HIIE and MIE (P = 0.72, ES = 0.16). Plasma triacylglycerol concentration and total antioxidant status concentration were not different between trials. We conclude that exercise intensity plays an important role in protecting the vasculature from the deleterious effects of a HFM. Performing HIIE may provide superior vascular benefits than MIE in adolescent groups. Copyright © 2015 the American Physiological Society.

Thermoregulatory responses in exercising rats: methodological aspects and relevance to human physiology.

PubMed

Wanner, Samuel Penna; Prímola-Gomes, Thales Nicolau; Pires, Washington; Guimarães, Juliana Bohnen; Hudson, Alexandre Sérvulo Ribeiro; Kunstetter, Ana Cançado; Fonseca, Cletiana Gonçalves; Drummond, Lucas Rios; Damasceno, William Coutinho; Teixeira-Coelho, Francisco

2015-01-01

Rats are used worldwide in experiments that aim to investigate the physiological responses induced by a physical exercise session. Changes in body temperature regulation, which may affect both the performance and the health of exercising rats, are evident among these physiological responses. Despite the universal use of rats in biomedical research involving exercise, investigators often overlook important methodological issues that hamper the accurate measurement of clear thermoregulatory responses. Moreover, much debate exists regarding whether the outcome of rat experiments can be extrapolated to human physiology, including thermal physiology. Herein, we described the impact of different exercise intensities, durations and protocols and environmental conditions on running-induced thermoregulatory changes. We focused on treadmill running because this type of exercise allows for precise control of the exercise intensity and the measurement of autonomic thermoeffectors associated with heat production and loss. Some methodological issues regarding rat experiments, such as the sites for body temperature measurements and the time of day at which experiments are performed, were also discussed. In addition, we analyzed the influence of a high body surface area-to-mass ratio and limited evaporative cooling on the exercise-induced thermoregulatory responses of running rats and then compared these responses in rats to those observed in humans. Collectively, the data presented in this review represent a reference source for investigators interested in studying exercise thermoregulation in rats. In addition, the present data indicate that the thermoregulatory responses of exercising rats can be extrapolated, with some important limitations, to human thermal physiology.

Thermoregulatory responses in exercising rats: methodological aspects and relevance to human physiology

PubMed Central

Wanner, Samuel Penna; Prímola-Gomes, Thales Nicolau; Pires, Washington; Guimarães, Juliana Bohnen; Hudson, Alexandre Sérvulo Ribeiro; Kunstetter, Ana Cançado; Fonseca, Cletiana Gonçalves; Drummond, Lucas Rios; Damasceno, William Coutinho; Teixeira-Coelho, Francisco

2015-01-01

Rats are used worldwide in experiments that aim to investigate the physiological responses induced by a physical exercise session. Changes in body temperature regulation, which may affect both the performance and the health of exercising rats, are evident among these physiological responses. Despite the universal use of rats in biomedical research involving exercise, investigators often overlook important methodological issues that hamper the accurate measurement of clear thermoregulatory responses. Moreover, much debate exists regarding whether the outcome of rat experiments can be extrapolated to human physiology, including thermal physiology. Herein, we described the impact of different exercise intensities, durations and protocols and environmental conditions on running-induced thermoregulatory changes. We focused on treadmill running because this type of exercise allows for precise control of the exercise intensity and the measurement of autonomic thermoeffectors associated with heat production and loss. Some methodological issues regarding rat experiments, such as the sites for body temperature measurements and the time of day at which experiments are performed, were also discussed. In addition, we analyzed the influence of a high body surface area-to-mass ratio and limited evaporative cooling on the exercise-induced thermoregulatory responses of running rats and then compared these responses in rats to those observed in humans. Collectively, the data presented in this review represent a reference source for investigators interested in studying exercise thermoregulation in rats. In addition, the present data indicate that the thermoregulatory responses of exercising rats can be extrapolated, with some important limitations, to human thermal physiology. PMID:27227066

Evaluation of anaerobic threshold in non-pregnant and pregnant rats.

PubMed

Netto, Aline Oliveira; Macedo, Nathália C D; Gallego, Franciane Q; Sinzato, Yuri K; Volpato, Gustavo T; Damasceno, Débora C

2017-01-01

Several studies present different methodologies and results about intensity exercise, and many of them are performed in male rats. However, the impact of different type, intensity, frequency and duration of exercise on female rats needs more investigation. From the analysis of blood lactate concentration during lactate minimum test (LacMin) in the swimming exercise, the anaerobic threshold (AT) was identified, which parameter is defined as the transition point between aerobic and anaerobic metabolism. LacMin test is considered a good indicator of aerobic conditioning and has been used in prescription of training in different exercise modalities. However, there is no evidence of LacMin test in female rats. The objective was to determine AT in non-pregnant and pregnant Wistar rats. The LacMin test was performed and AT defined for mild exercise intensity was from a load equivalent to 1% of body weight (bw), moderate exercise as carrying 4% bw and severe intensity as carrying 7% bw. In pregnant rats, the AT was reached at a lower loading from 5.0% to 5.5% bw, while in non-pregnant the load was from 5.5% to 6.0% bw. Thus, this study was effective to identify exercise intensities in pregnant and non-pregnant rats using anaerobic threshold by LacMin test.

Acute psychological benefits of aerobic exercise: a field study into the effects of exercise characteristics.

PubMed

Rendi, Mária; Szabo, Attila; Szabó, Tamás; Velenczei, Attila; Kovács, Arpád

2008-03-01

Eighty volunteers were tested in their natural exercise environment consisting of a fitness centre they regularly attended. Half of the sample exercised on a stationary bicycle, the other half on a treadmill. All participants filled in the Exercise-Induced Feeling Inventory before and after their 20 min of exercise that was performed at self-selected workload. The results revealed that exercise intensity and the other parallel measures like heart rate, perceived exercise intensity and estimates of burned calories were higher in participants who ran in contrast to those who cycled. There were no differences in self-reports of enjoyment of the exercise sessions and in the psychological improvements from pre- to post-exercise between the groups. It is concluded that significant psychological improvements occur even after a 20-min bout of exercise and these changes are independent of the workload or exercise intensity.

The effect of high intensity interval training on cardioprotection against ischemia-reperfusion injury in wistar rats

PubMed Central

Rahimi, Mostafa; Shekarforoush, Shahnaz; Asgari, Ali Reza; Khoshbaten, Ali; Rajabi, Hamid; Bazgir, Behzad; Mohammadi, Mohammad Taghi; Sobhani, Vahid; Shakibaee, Abolfazl

2015-01-01

The aims of the present study were to determine whether short term high intensity interval training (HIIT) could protect the heart against ischemia reperfusion (IR) injury; and if so, to evaluate how long the exercise-associated protection can be lasted. Sixty-three rats were randomly assigned into sedentary (n = 15), sham (n = 7), and exercise groups (n = 41). Rats in the exercise groups performed 5 consecutive days of HIIT on treadmill: 5 min warm up with 50 % VO2max, 6×2 min with 95-105 % VO2max (about 40 to 45 m/min), 5×2 min recovery with 65-75 % VO2max (about 28 to 32 m/min), and 3 min cool down with 50 % VO2max, all at 0 % grade. Animals exposed to an in vivo cardiac IR surgery, performed at days 1, 7, and 14 following the final exercise session. Ischemia-induced arrhythmias, myocardial infarct size (IS), plasma lactate dehydrogenase (LDH) and creatine kinase (CK) activities were measured in all animals. Compared to sedentary rats, exercised animals sustained less IR injury as evidenced by a lower size of infarction and lower levels of LDH and CK at day one and day 7 post exercise. In comparison of sedentary group, IS significantly decreased in EX-IR1 and EX-IR7 groups (50 and 35 %, respectively), but not in EX-IR14 group (19 %). The exercise-induced cardioprotection disappeared 14 days following exercise cessation. There were no significant changes in ischemia-induced arrhythmia between exercised and sedentary rats. The results clearly demonstrate that HIIT protects the heart against myocardial IR injury. This protective effect can be sustained for at least one week following the cessation of the training. PMID:26417361

Development and validation of a risk calculator predicting exercise-induced ventricular arrhythmia in patients with cardiovascular disease.

PubMed

Hermes, Ilarraza-Lomelí; Marianna, García-Saldivia; Jessica, Rojano-Castillo; Carlos, Barrera-Ramírez; Rafael, Chávez-Domínguez; María Dolores, Rius-Suárez; Pedro, Iturralde

2016-10-01

Mortality due to cardiovascular disease is often associated with ventricular arrhythmias. Nowadays, patients with cardiovascular disease are more encouraged to take part in physical training programs. Nevertheless, high-intensity exercise is associated to a higher risk for sudden death, even in apparently healthy people. During an exercise testing (ET), health care professionals provide patients, in a controlled scenario, an intense physiological stimulus that could precipitate cardiac arrhythmia in high risk individuals. There is still no clinical or statistical tool to predict this incidence. The aim of this study was to develop a statistical model to predict the incidence of exercise-induced potentially life-threatening ventricular arrhythmia (PLVA) during high intensity exercise. 6415 patients underwent a symptom-limited ET with a Balke ramp protocol. A multivariate logistic regression model where the primary outcome was PLVA was performed. Incidence of PLVA was 548 cases (8.5%). After a bivariate model, thirty one clinical or ergometric variables were statistically associated with PLVA and were included in the regression model. In the multivariate model, 13 of these variables were found to be statistically significant. A regression model (G) with a X(2) of 283.987 and a p<0.001, was constructed. Significant variables included: heart failure, antiarrhythmic drugs, myocardial lower-VD, age and use of digoxin, nitrates, among others. This study allows clinicians to identify patients at risk of ventricular tachycardia or couplets during exercise, and to take preventive measures or appropriate supervision. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Dynamic Warm-Up Protocols, With and Without a Weighted Vest, and Fitness Performance in High School Female Athletes

PubMed Central

Faigenbaum, Avery D; McFarland, James E; Schwerdtman, Jeff A; Ratamess, Nicholas A; Kang, Jie; Hoffman, Jay R

2006-01-01

Context: Recent authors have not found substantial evidence to support the use of static stretching for improving performance, so interest in dynamic warm-up procedures has risen. Our findings may improve the understanding of the acute effects of different types of pre-exercise protocols on performance and may help clinicians develop effective warm-up protocols for sports practice and competition. Objective: To examine the acute effects of 4 warm-up protocols with and without a weighted vest on anaerobic performance in female high school athletes. Design: Randomized, counterbalanced, repeated-measures design. Setting: High school fitness center. Patients or Other Participants: Eighteen healthy high school female athletes (age = 15.3 ± 1.2 years, height = 166.3 ± 9.1 cm, mass = 61.6 ± 10.4 kg). Intervention(s): After 5 minutes of jogging, subjects performed 4 randomly ordered warm-up protocols: (1) Five static stretches (2 × 30 seconds) (SS), (2) nine moderate-intensity to high-intensity dynamic exercises (DY), (3) the same 9 dynamic exercises performed with a vest weighted with 2% of body mass (DY2), and (4) the same 9 dynamic exercises performed with a vest weighted with 6% of body mass (DY6). Main Outcome Measure(s): Vertical jump, long jump, seated medicine ball toss, and 10-yard sprint. Results: Vertical jump performance was significantly greater after DY (41.3 ± 5.4 cm) and DY2 (42.1 ± 5.2 cm) compared with SS (37.1 ± 5.1 cm), and long jump performance was significantly greater after DY2 (180.5 ± 20.3 cm) compared with SS (160.4 ± 20.8 cm) ( P ≤ .05). No significant differences between trials were observed for the seated medicine ball toss or 10-yard sprint. Conclusions: A dynamic warm-up performed with a vest weighted with 2% of body mass may be the most effective warm-up protocol for enhancing jumping performance in high school female athletes. PMID:17273458

Creatine and Caffeine: Considerations for Concurrent Supplementation.

PubMed

Trexler, Eric T; Smith-Ryan, Abbie E

2015-12-01

Nutritional supplementation is a common practice among athletes, with creatine and caffeine among the most commonly used ergogenic aids. Hundreds of studies have investigated the ergogenic potential of creatine supplementation, with consistent improvements in strength and power reported for exercise bouts of short duration (≤ 30 s) and high intensity. Caffeine has been shown to improve endurance exercise performance, but results are mixed in the context of strength and sprint performance. Further, there is conflicting evidence from studies comparing the ergogenic effects of coffee and caffeine anhydrous supplementation. Previous research has identified independent mechanisms by which creatine and caffeine may improve strength and sprint performance, leading to the formulation of multi-ingredient supplements containing both ingredients. Although scarce, research has suggested that caffeine ingestion may blunt the ergogenic effect of creatine. While a pharmacokinetic interaction is unlikely, authors have suggested that this effect may be explained by opposing effects on muscle relaxation time or gastrointestinal side effects from simultaneous consumption. The current review aims to evaluate the ergogenic potential of creatine and caffeine in the context of high-intensity exercise. Research directly comparing coffee and caffeine anhydrous is discussed, along with previous studies evaluating the concurrent supplementation of creatine and caffeine.

High-intensity interval versus moderate-intensity continuous training: Superior metabolic benefits in diet-induced obesity mice.

PubMed

Wang, Ningning; Liu, Yang; Ma, Yanan; Wen, Deliang

2017-12-15

Exercise is beneficial in obesity, however, the debate about the value of high-intensity interval training (HIIT) vs. moderate-intensity continuous training (MICT) has been long lasting. Therefore, here we have compared the possible beneficial effects of two different exercise training regimes in a mouse model of diet-induced obesity (DIO). Following 7wk. on high fat diet (HFD), ten-week-old male ICR mice (n=30) were assigned to HIIT, distance-matched MICT or remained sedentary for the next 8 constitutive weeks while maintaining the dietary treatments. Age-matched sedentary mice with standard diet were used as a control (n=10). Exercise was performed on a motorized treadmill for 5days a week. Both modes of exercise ameliorated adiposity and related metabolic dysfunction induced by HFD and sedentary lifestyle, while mice following HIIT exhibited significantly lower body weight, percentage of fat mass and smaller adipocyte size. HIIT was more favorable in preventing liver lipid accumulation by restoring mRNA levels of genes involved in hepatic lipogenesis (SREBP1, ACC1, FAS) and β-oxidation (PPARα, CPT1a, HAD). In addition, HIIT was more efficient in mitigating adipose tissue inflammation and insulin insensitivity, partly dependent on abrogating phosphorylation of JNK/IRS1 (Ser307) pathway. Moreover, only HIIT led to pronounced beige adipocyte recruitment in inguinal subcutaneous adipose tissue. We conclude that HIIT contribute a more favorable regulation of metabolic dysfunctions in DIO mice compared with MICT. Copyright © 2017 Elsevier Inc. All rights reserved.

The Effects of Acute High-Intensity Interval Training on Hematological Parameters in Sedentary Subjects.

PubMed

Belviranli, Muaz; Okudan, Nilsel; Kabak, Banu

2017-07-19

The objective of the study was to determine the effects of acute high-intensity interval training (HIIT) on hematological parameters in sedentary men. Ten healthy, non-smoker, and sedentary men aged between 18 and 24 years participated in the study. All subjects performed four Wingate tests with 4 min intervals between the tests. Blood samples were collected at pre-exercise, immediately after, 3 and 6 h after the fourth Wingate test. Hematological parameters were analyzed in these samples. The results showed that hematocrit percentage, hemoglobin values, red cell count, mean cell volume, platelet count, total white cell count, and counts of the white cell subgroups increased immediately after the acute HIIT and their values began to return to resting levels 3 h after exercise, and completely returned to resting levels 6 h after exercise. In conclusion, acute HIIT causes an inflammatory response in blood.

High Intensity Interval Training Improves Physical Performance and Frailty in Aged Mice.

PubMed

Seldeen, Kenneth Ladd; Lasky, Ginger; Leiker, Merced Marie; Pang, Manhui; Personius, Kirkwood Ely; Troen, Bruce Robert

2018-03-14

Sarcopenia and frailty are highly prevalent in older individuals, increasing the risk of disability and loss of independence. High intensity interval training (HIIT) may provide a robust intervention for both sarcopenia and frailty by achieving both strength and endurance benefits with lower time commitments than other exercise regimens. To better understand the impacts of HIIT during aging, we compared 24-month-old C57BL/6J sedentary mice with those that were administered 10-minute uphill treadmill HIIT sessions three times per week over 16 weeks. Baseline and end point assessments included body composition, physical performance, and frailty based on criteria from the Fried physical frailty scale. HIIT-trained mice demonstrated dramatic improvement in grip strength (HIIT 10.9% vs -3.9% in sedentary mice), treadmill endurance (32.6% vs -2.0%), and gait speed (107.0% vs 39.0%). Muscles from HIIT mice also exhibited greater mass, larger fiber size, and an increase in mitochondrial biomass. Furthermore, HIIT exercise led to a dramatic reduction in frailty scores in five of six mice that were frail or prefrail at baseline, with four ultimately becoming nonfrail. The uphill treadmill HIIT exercise sessions were well tolerated by aged mice and led to performance gains, improvement in underlying muscle physiology, and reduction in frailty.

Effects of exercise training alone vs a combined exercise and nutritional lifestyle intervention on glucose homeostasis in prediabetic individuals: a randomised controlled trial.

PubMed

Slentz, Cris A; Bateman, Lori A; Willis, Leslie H; Granville, Esther O; Piner, Lucy W; Samsa, Gregory P; Setji, Tracy L; Muehlbauer, Michael J; Huffman, Kim M; Bales, Connie W; Kraus, William E

2016-10-01

Although the Diabetes Prevention Program (DPP) established lifestyle changes (diet, exercise and weight loss) as the 'gold standard' preventive therapy for diabetes, the relative contribution of exercise alone to the overall utility of the combined diet and exercise effect of DPP is unknown; furthermore, the optimal intensity of exercise for preventing progression to diabetes remains very controversial. To establish clinical efficacy, we undertook a study (2009 to 2013) to determine: how much of the effect on measures of glucose homeostasis of a 6 month programme modelled after the first 6 months of the DPP is due to exercise alone; whether moderate- or vigorous-intensity exercise is better for improving glucose homeostasis; and to what extent amount of exercise is a contributor to improving glucose control. The primary outcome was improvement in fasting plasma glucose, with improvement in plasma glucose AUC response to an OGTT as the major secondary outcome. The trial was a parallel clinical trial. Sedentary, non-smokers who were 45-75 year old adults (n = 237) with elevated fasting glucose (5.28-6.94 mmol/l) but without cardiovascular disease, uncontrolled hypertension, or diabetes, from the Durham area, were studied at Duke University. They were randomised into one of four 6 month interventions: (1) low amount (42 kJ kg body weight(-1) week(-1) [KKW])/moderate intensity: equivalent of expending 42 KKW (e.g. walking ∼16 km [8.6 miles] per week) with moderate-intensity (50% [Formula: see text]) exercise; (2) high amount (67 KKW)/moderate intensity: equivalent of expending 67 KKW (∼22.3 km [13.8 miles] per week) with moderate-intensity exercise; (3) high amount (67 KKW)/vigorous intensity: equivalent to group 2, but with vigorous-intensity exercise (75% [Formula: see text]); and (4) diet + 42 KKW moderate intensity: same as group 1 but with diet and weight loss (7%) to mimic the first 6 months of the DPP. Computer-generated randomisation lists were provided by our statistician (G. P. Samsa). The randomisation list was maintained by L. H. Willis and C. A. Slentz with no knowledge of or input into the scheduling, whereas all scheduling was done by L. A. Bateman, with no knowledge of the randomisation list. Subjects were automatically assigned to the next group listed on the randomisation sheet (with no ability to manipulate the list order) on the day that they came in for the OGTT, by L. H. Willis. All plasma analysis was done blinded by the individuals doing the measurements (i.e. lipids, glucose, insulin). Subjects and research staff (other than individuals analysing the blood) were not blinded to the group assignments. Number randomised, completers and number analysed with complete OGTT data for each group were: low-amount/moderate-intensity (61, 43, 35); high-amount/moderate-intensity (61, 44, 40); high-amount/vigorous-intensity (61, 43, 38); diet/exercise (54, 45, 37), respectively. Only the diet and exercise group experienced a decrease in fasting glucose (p < 0.001). The means and 95% CIs for changes in fasting glucose (mmol/l) for each group were: high-amount/moderate-intensity -0.07 (-0.20, 0.06); high-amount/vigorous 0.06 (-0.07, 0.19); low-amount/moderate 0.05 (-0.05, 0.15); and diet/exercise -0.32 (-0.46, -0.18). The effects sizes for each group (in the same order) were: 0.17, 0.15, 0.18 and 0.71, respecively. For glucose tolerance (glucose AUC of OGTT), similar improvements were observed for the diet and exercise (8.2% improvement, effect size 0.73) and the 67 KKW moderate-intensity exercise (6.4% improvement, effect size 0.60) groups; moderate-intensity exercise was significantly more effective than the same amount of vigorous-intensity exercise (p < 0.0207). The equivalent amount of vigorous-intensity exercise alone did not significantly improve glucose tolerance (1.2% improvement, effect size 0.21). Changes in insulin AUC, fasting plasma glucose and insulin did not differ among the exercise groups and were numerically inferior to the diet and exercise group. In the present clinical efficacy trial we found that a high amount of moderate-intensity exercise alone was very effective at improving oral glucose tolerance despite a relatively modest 2 kg change in body fat mass. These data, combined with numerous published observations of the strong independent relation between postprandial glucose concentrations and prediction of future diabetes, suggest that walking ∼18.2 km (22.3 km prescribed with 81.6% adherence in the 67 KKW moderate-intensity group) per week may be nearly as effective as a more intensive multicomponent approach involving diet, exercise and weight loss for preventing the progression to diabetes in prediabetic individuals. These findings have important implications for the choice of clinical intervention to prevent progression to type 2 diabetes for those at high risk. ClinicalTrials.gov NCT00962962 FUNDING: The study was funded by National Institutes for Health National Institute of Diabetes and Digestive and Kidney Diseases (NIH-NDDK) (R01DK081559).

Aerobic Exercise Training in Post-Polio Syndrome: Process Evaluation of a Randomized Controlled Trial.

PubMed

Voorn, Eric L; Koopman, Fieke S; Brehm, Merel A; Beelen, Anita; de Haan, Arnold; Gerrits, Karin H L; Nollet, Frans

2016-01-01

To explore reasons for the lack of efficacy of a high intensity aerobic exercise program in post-polio syndrome (PPS) on cardiorespiratory fitness by evaluating adherence to the training program and effects on muscle function. A process evaluation using data from an RCT. Forty-four severely fatigued individuals with PPS were randomized to exercise therapy (n = 22) or usual care (n = 22). Participants in the exercise group were instructed to exercise 3 times weekly for 4 months on a bicycle ergometer (60-70% heart rate reserve). The attendance rate was high (median 89%). None of the participants trained within the target heart rate range during >75% of the designated time. Instead, participants exercised at lower intensities, though still around the anaerobic threshold (AT) most of the time. Muscle function did not improve in the exercise group. Our results suggest that severely fatigued individuals with PPS cannot adhere to a high intensity aerobic exercise program on a cycle ergometer. Despite exercise intensities around the AT, lower extremity muscle function nor cardiorespiratory fitness improved. Improving the aerobic capacity in PPS is difficult through exercise primarily focusing on the lower extremities, and may require a more individualized approach, including the use of other large muscle groups instead. Netherlands National Trial Register NTR1371.

Understanding the factors that effect maximal fat oxidation.

PubMed

Purdom, Troy; Kravitz, Len; Dokladny, Karol; Mermier, Christine

2018-01-01

Lipids as a fuel source for energy supply during submaximal exercise originate from subcutaneous adipose tissue derived fatty acids (FA), intramuscular triacylglycerides (IMTG), cholesterol and dietary fat. These sources of fat contribute to fatty acid oxidation (FAox) in various ways. The regulation and utilization of FAs in a maximal capacity occur primarily at exercise intensities between 45 and 65% VO 2max , is known as maximal fat oxidation (MFO), and is measured in g/min. Fatty acid oxidation occurs during submaximal exercise intensities, but is also complimentary to carbohydrate oxidation (CHOox). Due to limitations within FA transport across the cell and mitochondrial membranes, FAox is limited at higher exercise intensities. The point at which FAox reaches maximum and begins to decline is referred to as the crossover point. Exercise intensities that exceed the crossover point (~65% VO 2max ) utilize CHO as the predominant fuel source for energy supply. Training status, exercise intensity, exercise duration, sex differences, and nutrition have all been shown to affect cellular expression responsible for FAox rate. Each stimulus affects the process of FAox differently, resulting in specific adaptions that influence endurance exercise performance. Endurance training, specifically long duration (>2 h) facilitate adaptations that alter both the origin of FAs and FAox rate. Additionally, the influence of sex and nutrition on FAox are discussed. Finally, the role of FAox in the improvement of performance during endurance training is discussed.

Postflight reconditioning for European Astronauts - A case report of recovery after six months in space.

PubMed

Petersen, Nora; Lambrecht, Gunda; Scott, Jonathan; Hirsch, Natalie; Stokes, Maria; Mester, Joachim

2017-01-01

Postflight reconditioning of astronauts is understudied. Despite a rigorous, daily inflight exercise countermeasures programme during six months in microgravity (μG) on-board the International Space Station (ISS), physiological impairments occur and postflight reconditioning is still required on return to Earth. Such postflight programmes are implemented by space agency reconditioning specialists. Case Description and Assessments: A 38 year old male European Space Agency (ESA) crewmember's pre- and postflight (at six and 21 days after landing) physical performance from a six-month mission to ISS are described. muscle strength (squat and bench press 1 Repetition Maximum) and power (vertical jump), core muscle endurance and hip flexibility (Sit and Reach, Thomas Test). In-flight, the astronaut undertook a rigorous daily (2-h) exercise programme. The 21 day postflight reconditioning exercise concept focused on motor control and functional training, and was delivered in close co-ordination by the ESA physiotherapist and exercise specialist to provide the crewmember with comprehensive reconditioning support. Despite an intensive inflight exercise programme for this highly motivated crewmember, postflight performance showed impairments at R+6 for most parameters, all of which recovered by R+21 except muscular power (jump tests). Regardless of intense inflight exercise countermeasures and excellent compliance to postflight reconditioning, postflight performance showed impairments at R+6 for most parameters. Complex powerful performance tasks took longer to return to preflight values. Research is needed to develop optimal inflight and postflight exercise programmes to overcome the negative effects of microgravity and return the astronaut to preflight status as rapidly as possible. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cardiovascular and Affective Outcomes of Active Gaming: Using the Nintendo Wii as a Cardiovascular Training Tool

PubMed Central

Naugle, Keith E.; Naugle, Kelly M.; Wikstrom, Erik A.

2014-01-01

Naugle, KE, Naugle, KM, and Wikstrom, EA. Cardiovascular and affective outcomes of active gaming: Using the Nintendo Wii as a cardiovascular training tool. J Strength Cond Res 28(2): 443–451, 2014–Active-video gaming is purported to produce similar cardiovascular responses as aerobic fitness activities. This study compared the emotional and cardiovascular effects of Wii games with those of traditional exercise in college-aged adults with different exercise backgrounds. Specifically, the percentage of heart rate reserve, rate of perceived exertion (RPE), level of enjoyment, and Positive and Negative Affect Schedule scores were compared between subjects who reported exercising frequently at high intensities (high-intensity exerciser group: age = 20.18 years [0.87]; Height = 165.23 cm [9.97]; Mass = 62.37 kg [11.61]), N = 11 and those who exercise more often at lower intensities (low-intensity exercisers group: age = 20.72 years [1.19]; Height = 164.39 cm [8.05]; Mass = 68.04 kg [10.71]), N = 11. The subjects completed six 20-minute exercises sessions: treadmill walking, stationary cycling, and Wii's Tennis, Boxing, Cycling, and Step. The low-intensity exerciser group achieved a greater percentage of heart rate reserve (a) during traditional exercise compared with that during Wii boxing, (b) playing Wii boxing compared with that for Wii tennis, and (c) playing Wii boxing compared with that when the high-intensity exercisers group played any Wii games (p < 0.05). The RPE was greater for boxing and cycling compared with that for tennis and step (p < 0.05). Ratings of enjoyment and the increase in positive emotion were greater for boxing and for tennis compared with those for traditional exercises (p < 0.05). Results suggest that Wii boxing shows the greatest potential as a cardiovascular fitness tool among the Wii games, particularly for individuals who typically exercise at lower intensities. PMID:23660574

The anticipatory regulation of performance: the physiological basis for pacing strategies and the development of a perception-based model for exercise performance.

PubMed

Tucker, R

2009-06-01

During self-paced exercise, the exercise work rate is regulated by the brain based on the integration of numerous signals from various physiological systems. It has been proposed that the brain regulates the degree of muscle activation and thus exercise intensity specifically to prevent harmful physiological disturbances. It is presently proposed how the rating of perceived exertion (RPE) is generated as a result of the numerous afferent signals during exercise and serves as a mediator of any subsequent alterations in skeletal muscle activation levels and exercise intensity. A conceptual model for how the RPE mediates feedforward, anticipatory regulation of exercise performance is proposed, and this model is applied to previously described research studies of exercise in various conditions, including heat, hypoxia and reduced energy substrate availability. Finally, the application of this model to recent novel studies that altered pacing strategies and performance is described utilising an RPE clamp design, central nervous system drugs and the provision of inaccurate duration or distance feedback to exercising athletes.

Effects of high intensity exercise on isoelectric profiles and SDS-PAGE mobility of erythropoietin.

PubMed

Voss, S; Lüdke, A; Romberg, S; Schänzer, E; Flenker, U; deMarees, M; Achtzehn, S; Mester, J; Schänzer, W

2010-06-01

Exercise induced proteinuria is a common phenomenon in high performance sports. Based on the appearance of so called "effort urines" in routine doping analysis the purpose of this study was to investigate the influence of exercise induced proteinuria on IEF profiles and SDS-PAGE relative mobility values (rMVs) of endogenous human erythropoietin (EPO). Twenty healthy subjects performed cycle-ergometer exercise until exhaustion. VO (2)max, blood lactate, urinary proteins and urinary creatinine were analysed to evaluate the exercise performance and proteinuria. IEF and SDS-PAGE analyses were performed to test for differences in electrophoretic behaviour of the endogenous EPO before and after exercise. All subjects showed increased levels of protein/creatinine ratio after performance (8.8+/-5.2-26.1+/-14.4). IEF analysis demonstrated an elevation of the relative amount of basic band areas (13.9+/-11.3-36.4+/-12.6). Using SDS-PAGE analysis we observed a decrease in rMVs after exercise and no shift in direction of the recombinant human EPO (rhEPO) region (0.543+/-0.013-0.535+/-0.012). Following identification criteria of the World Anti Doping Agency (WADA) all samples were negative. The implementation of the SDS-PAGE method represents a good solution to distinguish between results influenced by so called effort urines and results of rhEPO abuse. Thus this method can be used to confirm adverse analytical findings.

Effect of high-intensity interval exercise on lipid oxidation during postexercise recovery.

PubMed

Malatesta, Davide; Werlen, Catherine; Bulfaro, Stefano; Chenevière, Xavier; Borrani, Fabio

2009-02-01

The aim of this study was to examine whether lipid oxidation predominates during 3 h of postexercise recovery in high-intensity interval exercise as compared with moderate-intensity continuous exercise on a cycle ergometer in fit young men (n = 12; 24.6 +/- 0.6 yr). The energy substrate partitioning was evaluated during and after high-intensity submaximal interval exercise (INT, 1-min intervals at 80% of maximal aerobic power output [Wmax] with an intervening 1 min of active recovery at 40% Wmax) and 60-min moderate-intensity continuous exercise at 45% of maximal oxygen uptake (C45%) as well as a time-matched resting control trial (CON). Exercise bouts were matched for mechanical work output. During exercise, a significantly greater contribution of CHO and a lower contribution of lipid to energy expenditure were found in INT (512.7 +/- 26.6 and 41.0 +/- 14.0 kcal, respectively) than in C45% (406.3 +/- 21.2 and 170.3 +/- 24.0 kcal, respectively; P < 0.001) despite similar overall energy expenditure in both exercise trials (P = 0.13). During recovery, there were no significant differences between INT and C45% in substrate turnover and oxidation (P > 0.05). On the other hand, the mean contribution of lipids to energy yield was significantly higher after exercise trials (C45% = 61.3 +/- 4.2 kcal; INT = 66.7 +/- 4.7 kcal) than after CON (51.5 +/- 3.4 kcal; P < 0.05). These findings show that lipid oxidation during postexercise recovery was increased by a similar amount on two isoenergetic exercise bouts of different forms and intensities compared with the time-matched no-exercise control trial.

High intensity interval exercise decreases IL-8 and enhances the immunomodulatory cytokine interleukin-10 in lean and overweight-obese individuals.

PubMed

Dorneles, Gilson P; Haddad, Desirée O; Fagundes, Viviane O; Vargas, Bruna K; Kloecker, Alana; Romão, Pedro R T; Peres, Alessandra

2016-01-01

To compare the effects of two interval exercises with different intensities on acute inflammatory response in lean and overweight-obese subjects. Ten lean (BMI<24.9kg/m(2)) and 12 overweight-obese (BMI 25 to <34.9kg/m(2)) males performed two conditions in randomly assigned: (1) high intensity interval exercise (HIIE) 10×60s (85-90%PMax)/75s (50%PMax); (2) moderate intensity interval exercise (MIIE) 10×60s (70-75%PMax)/60s (50%PMax), with blood collections at pre, immediately and 30min post each exercise bouts to evaluate total and differential leukocyte counts, serum creatine kinase (CK), lactate dehydrogenase (LDH) and systemic levels of IL-1ra, IL-6, IL-8, IL-10, IL-17a and CCL2. In lean group, HIIE induced a significant increase in total leukocytes and monocyte, while MIIE session did not change the number of leukocytes. Overweight-obese group presented similar increase in leukocytes, monocytes and lymphocytes in both HIIE and MIIE sessions. At baseline, overweight-obese group showed high levels of CK, IL-8, IL-6 and CCL2 and lower concentrations of IL-10 compared to lean group. The MIIE did not alter the cytokine concentrations in both groups, independently of the time analysis. The HIIE induced significant decrease in IL-8 levels 30min post session in both the groups, and a progressive elevation in IL-10 levels immediately and 30min post in lean and overweight-obese. Regarding IL-6, overweight-obese subjects presented progressive increase either immediately and 30min after HIIE, while lean individuals presented significant increase only 30min after exercise. The acute inflammatory response to interval exercise is intensity-dependent. Although obesity influences the basal concentrations of several cytokines, only HIIE induced important alterations in IL-8 and IL-10 levels, which may have important implications in the control of chronic low-grade inflammation in obesity. Copyright © 2015 Elsevier Ltd. All rights reserved.

The association between pregame snacks and exercise intensity, stress, and fatigue in children.

PubMed

Sacheck, Jennifer M; Rasmussen, Helen M; Hall, Meghan M; Kafka, Tamar; Blumberg, Jeffrey B; Economos, Christina D

2014-05-01

To investigate the association between pregame snacks varying in macronutrient content and exercise intensity, physiological stress, and fatigue in young soccer players. One hour before a 50-min soccer game, children (n = 79; 9.1 ± 0.8 y) were randomly assigned to consume a raisin-, peanut-butter-, or cereal-based snack. Body mass index, blood glucose, and salivary measures of stress (cortisol and immunoglobulin A-IgA) were measured pre- and post-game. Exercise intensity was measured by accelerometry. Self-administered questionnaires were used to assess diet quality and fatigue. Analysis of covariance was used to examine the relationship between pregame snacks and biochemical outcomes. Postgame glucose and cortisol increased [12.9 ± 21.3 mg/dL (p < .001) and 0.04 ± 0.10 μg/dL (p < .05), respectively] and IgA decreased (-2.3 ± 9.6 μg/mL; p < .001) from pregame values. The pregame snack was not associated with exercise intensity or post-game outcome; however, children consuming the cereal-based (high-sugar and high-glycemic index (GI)) snack exercised more intensely than the 2 lower-GI snack groups (p < .05). Children who consumed the high-sugar, high-GI snack also reported more symptoms of fatigue (p < .05). A high-sugar, high-GI pregame snack was associated with exercise intensity and fatigue but not changes in blood sugar or stress biomarkers following a soccer game in children.

A Single Bout of Moderate Aerobic Exercise Improves Motor Skill Acquisition

PubMed Central

Statton, Matthew A.; Encarnacion, Marysol; Celnik, Pablo; Bastian, Amy J.

2015-01-01

Long-term exercise is associated with improved performance on a variety of cognitive tasks including attention, executive function, and long-term memory. Remarkably, recent studies have shown that even a single bout of aerobic exercise can lead to immediate improvements in declarative learning and memory, but less is known about the effect of exercise on motor learning. Here we sought to determine the effect of a single bout of moderate intensity aerobic exercise on motor skill learning. In experiment 1, we investigated the effect of moderate aerobic exercise on motor acquisition. 24 young, healthy adults performed a motor learning task either immediately after 30 minutes of moderate intensity running, after running followed by a long rest period, or after slow walking. Motor skill was assessed via a speed-accuracy tradeoff function to determine how exercise might differentially affect two distinct components of motor learning performance: movement speed and accuracy. In experiment 2, we investigated both acquisition and retention of motor skill across multiple days of training. 20 additional participants performed either a bout of running or slow walking immediately before motor learning on three consecutive days, and only motor learning (no exercise) on a fourth day. We found that moderate intensity running led to an immediate improvement in motor acquisition for both a single session and on multiple sessions across subsequent days, but had no effect on between-day retention. This effect was driven by improved movement accuracy, as opposed to speed. However, the benefit of exercise was dependent upon motor learning occurring immediately after exercise–resting for a period of one hour after exercise diminished the effect. These results demonstrate that moderate intensity exercise can prime the nervous system for the acquisition of new motor skills, and suggest that similar exercise protocols may be effective in improving the outcomes of movement rehabilitation programs. PMID:26506413

Acute Exercise Improves Motor Memory Consolidation in Preadolescent Children

PubMed Central

Lundbye-Jensen, Jesper; Skriver, Kasper; Nielsen, Jens B.; Roig, Marc

2017-01-01

Objective: The ability to acquire new motor skills is essential both during childhood and later in life. Recent studies have demonstrated that an acute bout of exercise can improve motor memory consolidation in adults. The objective of the present study was to investigate whether acute exercise protocols following motor skill practice in a school setting can also improve long-term retention of motor memory in preadolescent children. Methods: Seventy-seven pre-adolescent children (age 10.5 ± 0.75 (SD)) participated in the study. Prior to the main experiment age, BMI, fitness status and general physical activity level was assessed in all children and they were then randomly allocated to three groups. All children practiced a visuomotor tracking task followed by 20 min of rest (CON), high intensity intermittent floorball (FLB) or running (RUN) with comparable exercise intensity and duration for exercise groups. Delayed retention of motor memory was assessed 1 h, 24 h and 7 days after motor skill acquisition. Results: During skill acquisition, motor performance improved significantly to the immediate retention test with no differences between groups. One hour following skill acquisition, motor performance decreased significantly for RUN. Twenty-four hours following skill acquisition there was a tendency towards improved performance for FLB but no significant effects. Seven days after motor practice however, both FLB and RUN performed better when compared to their immediate retention test indicating significant offline gains. This effect was not observed for CON. In contrast, 7 days after motor practice, retention of motor memory was significantly better for FLB and RUN compared to CON. No differences were observed when comparing FLB and RUN. Conclusions: Acute intense intermittent exercise performed immediately after motor skill acquisition facilitates long-term motor memory in pre-adolescent children, presumably by promoting memory consolidation. The results also demonstrate that the effects can be accomplished in a school setting. The positive effect of both a team game (i.e., FLB) and running indicates that the observed memory improvements are determined to a larger extent by physiological factors rather than the types of movements performed during the exercise protocol. PMID:28473761

Upright exercise or supine lower body negative pressure exercise maintains exercise responses after bed rest

NASA Technical Reports Server (NTRS)

Lee, S. M.; Bennett, B. S.; Hargens, A. R.; Watenpaugh, D. E.; Ballard, R. E.; Murthy, G.; Ford, S. R.; Fortney, S. M.

1997-01-01

Adaptation to bed rest or space flight is accompanied by an impaired ability to exercise in an upright position. We hypothesized that a daily, 30-min bout of intense, interval exercise in upright posture or supine against lower body negative pressure (LBNP) would maintain upright exercise heart rate and respiratory responses after bed rest. Twenty-four men (31 +/- 3 yr) underwent 5 d of 6 degree head-down tilt: eight performed no exercise (CON), eight performed upright treadmill exercise (UPex), and eight performed supine treadmill exercise against LBNP at -51.3 +/- 0.4 mm Hg (LBNPex). Submaximal treadmill exercise responses (56, 74, and 85% of VO2peak) were measured pre- and post-bed rest. In CON, submaximal heart rate, respiratory exchange ratio, and ventilation were significantly greater (P < or = 0.05) after bed rest. In UPex and LBNPex, submaximal exercise responses were similar pre- and post-bed rest. Our results indicate that a daily 30-min bout of intense, interval upright exercise training or supine exercise training against LBNP is sufficient to maintain upright exercise responses after 5 d of bed rest. These results may have important implications for the development of exercise countermeasures during space flight.

The effect of exercise intensity and excess postexercise oxygen consumption on postprandial blood lipids in physically inactive men.

PubMed

Littlefield, Laurel A; Papadakis, Zacharias; Rogers, Katie M; Moncada-Jiménez, José; Taylor, J Kyle; Grandjean, Peter W

2017-09-01

Reductions in postprandial lipemia have been observed following aerobic exercise of sufficient energy expenditure. Increased excess postexercise oxygen consumption (EPOC) has been documented when comparing high- versus low-intensity exercise. The contribution of EPOC energy expenditure to alterations in postprandial lipemia has not been determined. The purpose of this study was to evaluate the effects of low- and high-intensity exercise on postprandial lipemia in healthy, sedentary, overweight and obese men (age, 43 ± 10 years; peak oxygen consumption, 31.1 ± 7.5 mL·kg -1 ·min -1 ; body mass index, 31.8 ± 4.5 kg/m 2 ) and to determine the contribution of EPOC to reductions in postprandial lipemia. Participants completed 4 conditions: nonexercise control, low-intensity exercise at 40%-50% oxygen uptake reserve (LI), high-intensity exercise at 70%-80% oxygen uptake reserve (HI), and HI plus EPOC re-feeding (HI+EERM), where the difference in EPOC energy expenditure between LI and HI was re-fed in the form of a sports nutrition bar (Premier Nutrition Corp., Emeryville, Calif., USA). Two hours following exercise participants ingested a high-fat (1010 kcals, 99 g sat fat) test meal. Blood samples were obtained before exercise, before the test meal, and at 2, 4, and 6 h postprandially. Triglyceride incremental area under the curve was significantly reduced following LI, HI, and HI+EERM when compared with nonexercise control (p < 0.05) with no differences between the exercise conditions (p > 0.05). In conclusions, prior LI and HI exercise equally attenuated postprandial triglyceride responses to the test meal. The extra energy expended during EPOC does not contribute significantly to exercise energy expenditure or to reductions in postprandial lipemia in overweight men.

A step towards personalized sports nutrition: carbohydrate intake during exercise.

PubMed

Jeukendrup, Asker

2014-05-01

There have been significant changes in the understanding of the role of carbohydrates during endurance exercise in recent years, which allows for more specific and more personalized advice with regard to carbohydrate ingestion during exercise. The new proposed guidelines take into account the duration (and intensity) of exercise and advice is not restricted to the amount of carbohydrate; it also gives direction with respect to the type of carbohydrate. Studies have shown that during exercise lasting approximately 1 h in duration, a mouth rinse or small amounts of carbohydrate can result in a performance benefit. A single carbohydrate source can be oxidized at rates up to approximately 60 g/h and this is the recommendation for exercise that is more prolonged (2-3 h). For ultra-endurance events, the recommendation is higher at approximately 90 g/h. Carbohydrate ingested at such high ingestion rates must be a multiple transportable carbohydrates to allow high oxidation rates and prevent the accumulation of carbohydrate in the intestine. The source of the carbohydrate may be a liquid, semisolid, or solid, and the recommendations may need to be adjusted downward when the absolute exercise intensity is low and thus carbohydrate oxidation rates are also low. Carbohydrate intake advice is independent of body weight as well as training status. Therefore, although these guidelines apply to most athletes, they are highly dependent on the type and duration of activity. These new guidelines may replace the generic existing guidelines for carbohydrate intake during endurance exercise.

The effect of two kinds of T-shirts on physiological and psychological thermal responses during exercise and recovery.

PubMed

Brazaitis, Marius; Kamandulis, Sigitas; Skurvydas, Albertas; Daniusevičiūtė, Laura

2010-12-01

The aim of this study was to investigate the physiological and psychological responses during and after high-intensity exercise in a warm and humid environment in subjects wearing shirts of different fabrics. Eight healthy men exercised on two separate occasions, in random order, wearing two types of long-sleeve T-shirt: one made of polyester (PES) and the other of cotton fabric (CT). They performed three 20 min exercise bouts, with 5 min rest between each, and then rested in a chair for 60 min to recover. The ambient temperature was 25 °C and relative humidity was 60%. The exercise comprised of treadmill running at 8 km/h at 1° grade. Rectal temperature, skin temperatures at eight sites, heart rate, T-shirt mass and ratings of thermal, clothing wettedness, and shivering/sweating sensation were measured before the experiment, during the 5 min rest period after each exercise bout, and during recovery. Nude body mass was measured before the experiment and during recovery. The physiological stress index showed that the exercise produced a state of very high heat stress. Compared with exercise wearing the CT shirt, exercise wearing the PES fabric produced a greater sweating efficiency and less clothing regain (i.e., less sweat retention), but thermophysiological and subjective sensations during the intermittent high-intensity exercise were similar for both fabrics. However, skin temperature returned to the pre-exercise level faster, and the thermal and rating of shivering/sweating sensation were lower after exercise in the warm and humid environment in subjects wearing PES than when wearing the more traditional CT fabric. Copyright © 2010 Elsevier Ltd. All rights reserved.

Highly increased Troponin I levels following high-intensity endurance cycling may detect subclinical coronary artery disease in presumably healthy leisure sport cyclists: The North Sea Race Endurance Exercise Study (NEEDED) 2013.

PubMed

Skadberg, Øyvind; Kleiven, Øyunn; Bjørkavoll-Bergseth, Magnus; Melberg, Tor; Bergseth, Rolf; Selvåg, Jone; Auestad, Bjørn; Greve, Ole J; Dickstein, Kenneth; Aarsland, Torbjørn; Ørn, Stein

2017-05-01

Background Circulating cardiac troponin levels increase following prolonged intense physical exercise. The aim of this study was to identify participants with highly elevated cardiac troponins after prolonged, high intensity exercise, and to evaluate these for subclinical coronary artery disease. Methods and results Ninety-seven recreational cyclists without known cardiovascular disease or diabetes, participating in a 91 km mountain bike race were included, 74 (76%) were males, age: 43 ± 10 years, race duration: 4.2 (3.6-4.7) h. Blood samples, rest electrocardiogram and physical examination were obtained 24 h prior to, and at 0, 3 and 24 h following the race. Median cardiac troponin I level at baseline: 3.4 (2.1-4.9) ng/l (upper limit of normal: 30.0 ng/l). There was a highly significant ( p < 0.0001) increase in circulating cardiac troponin I in all participants: immediately following the race; 50.5 (28.5-71.9) ng/l, peaking at 3 h 69.3 (42.3-97.7) ng/l and declining at 24 h: 14.2 (8.5-27.9) ng/l. No cyclist had symptoms or rest electrocardiogram changes compatible with coronary artery disease during or following the race. Coronary artery disease was detected by coronary angiography in the three cyclists with the three of the four highest cardiac troponin values (>370 ng/l) at 3 and 24 h following the race. Computed tomographic coronary angiography was performed in an additional 10 riders with the subsequently highest cardiac troponin I values, without identifying underlying coronary artery disease. Conclusions This study suggests that there is a pathologic cardiac troponin I response following exercise in individuals with subclinical coronary artery disease. This response may be associated with an excessive cardiac troponin I increase at 3 and 24 h following prolonged high-intensity exercise.

Comparison of Methods for Determining Aerobic Exercise Intensity Using Heart Rate in Acute Leukemia Patients Prior to Induction Chemotherapy

PubMed Central

Story, Christina; Bryant, Ashley Leak; Phillips, Brett; Bailey, Charlotte; Shields, Edgar W.; Battaglini, Claudio

2018-01-01

Introduction Cardiopulmonary exercise testing (CPET), the gold standard of cardiopulmonary evaluation, is used to determine VO2 levels at different aerobic exercise training intensities; however, it may not be feasible to conduct CPET in all clinical settings. Aims To compare the heart rate reserve (HRR) and percent of 220-age methods for prescribing cycle ergometry exercise intensity using heart rate (HR) against the HRs obtained during a CPET in adults undergoing treatment for acute leukemia (AL). Methods In this exploratory study, part of a larger randomized controlled trial, 14 adults with AL completed CPET on a cycle ergometer with indirect calorimetry within 96 hr of admission to a cancer hospital to determine VO2peak and HR corresponding to low (40% VO2peak), moderate (60% VO2peak), and high (75% VO2peak) exercise intensities. Analyses of variance were used to compare estimated HR for each intensity level using the HRR and percent of 220-age methods with HR determined via VO2peak. Results HR corresponding to low-intensity exercise differed significantly across all three methods (p ≤ .05). No significant differences were observed between HR estimated via the percent of 220-age method and determined via VO2peak at moderate (100 ± 8 and 113 ± 24 bpm, p = .122) or high intensities (125 ± 10 and 123 ± 25 bpm, p = .994). Conclusion In adults with AL, HR-based methods for defining aerobic exercise intensities should be used with caution. At low intensity, neither should be used, while at moderate and high intensities, the percent of 220-age equation might serve as an adequate substitute for CPET. PMID:26933148

Protection of Lotus Seedpod Proanthocyanidins on Organs and Tissues under High-intensity Excercise

PubMed Central

Mengyan, Zhang

2015-01-01

Lotus seedpod proanthocyanidins (LSPC) as a kind of polyphenols is widely used in medicines, cosmetics, health products. High-intensity exercise can cause damage to the body's organs and tissues. Different doses of LSPC is given to mice to check the function of protect effect to the body's organs and tissues under high-intensity exercise. The hemoglobin (HB) content, red blood cell (RBC) number and white blood cell (WBC) number were tested for mice after exercise. The activity of superoxide dismutase (SOD) and the contents of glutathione (GSH) and malondialdehyde (MDA) in muscle and viscera were evaluated. The result showed that LSPC can effectively reduce inflammation reaction in the body of mice with high intensity exercise, alleviate oxidative stress-induced injury of tissues and organs, and execute protective function on skeletal muscle and cardiac muscle. And the LSPC could enhance myocardial anti-oxygen and enzymatic activity which suggests the protective effects of resveratrol against exercise-induced myocardial damage in mice. PMID:26998176

Chronic lactate supplementation does not improve blood buffering capacity and repeated high-intensity exercise.

PubMed

Oliveira, L F; de Salles Painelli, V; Nemezio, K; Gonçalves, L S; Yamaguchi, G; Saunders, B; Gualano, B; Artioli, G G

2017-11-01

Since there is conflicting data on the buffering and ergogenic properties of calcium lactate (CL), we investigated the effect of chronic CL supplementation on blood pH, bicarbonate, and high-intensity intermittent exercise performance. Sodium bicarbonate (SB) was used as a positive control. Eighteen athletes participated in this double-blind, placebo-controlled, crossover, fully counterbalanced study. All participants underwent three different treatments: placebo (PL), CL, and SB. The dose was identical in all conditions: 500 mg/kg BM divided into four daily individual doses of 125 mg/kg BM, for five consecutive days, followed by a 2-7-day washout period. On the fifth day of supplementation, individuals undertook four 30-s Wingate bouts for upper body with 3-min recovery between bouts. Total mechanical work (TMW) for the overall protocol and for the initial (1st+2nd) and final (3rd+4th) bouts was determined at each session. Blood pH, bicarbonate, and lactate levels were determined at rest, immediately and 5 min after exercise. CL supplementation did not affect performance (P > 0.05 for the overall TMW as well for initial and final bouts), nor did it affect blood bicarbonate and pH prior to exercise. SB supplementation improved performance by 2.9% for overall TMW (P = 0.02) and 5.9% in the 3rd+4th bouts (P = 0001). Compared to the control session, SB also promoted higher increases in blood bicarbonate than CL and PL (+0.03 ± 0.04 vs +0.009 ± 0.02 and +0.01 ± 0.03, respectively). CL supplementation was not capable of enhancing high-intensity intermittent performance or changing extracellular buffering capacity challenging the notion that this dietary supplement is an effective buffering agent. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Age-related changes in physical and perceptual markers of recovery following high-intensity interval cycle exercise.

PubMed

Borges, Nattai R; Reaburn, Peter R; Doering, Thomas M; Argus, Christos K; Driller, Matthew W

2018-05-29

The purpose of this study was to compare physical performance, perceptual and haematological markers of recovery in well-trained masters and young cyclists across 48 h following a bout of repeated high-intensity interval exercise. Nine masters (mean ± SD; age = 55.6 ± 5.0 years) and eight young (age = 25.9 ± 3.0 years) cyclists performed a high-intensity interval exercise session consisting of 6 × 30 s intervals at 175% peak power output with 4.5 min rest between efforts. Maximal voluntary contraction (MVC), 10 s sprint (10SST), 30-min time trial (30TT) performance, creatine kinase concentration (CK) and perceptual measures of motivation, total recovery, fatigue and muscle soreness were collected at baseline and at standardised time points across the 48 h recovery period. No significant group-time interactions were observed for performance of MVC, 10SST, 30TT and CK (P > 0.05). A significant reduction in 10SST peak power was found in both masters (P = 0.002) and young (P = 0.003) cyclists at 1 h post exercise, however, both groups physically recovered at similar rates. Neither group showed significant (P > 0.05) or practically meaningful increases in CK (%∆ < 10%). A significant age-related difference was found for perceptual fatigue (P = 0.01) and analysis of effect size (ES) showed that perceptual recovery was delayed with masters cyclists reporting lower motivation (ES ±90%CI = 0.69 ± 0.77, moderate), greater fatigue (ES = 0.75 ± 0.93, moderate) and muscle soreness (ES = 0.61 ± 0.70, moderate) after 48 h of recovery. The delay in perceived recovery may have negative effects on long-term participation to systematic training.

Creatine supplementation with specific view to exercise/sports performance: an update

PubMed Central

2012-01-01

Creatine is one of the most popular and widely researched natural supplements. The majority of studies have focused on the effects of creatine monohydrate on performance and health; however, many other forms of creatine exist and are commercially available in the sports nutrition/supplement market. Regardless of the form, supplementation with creatine has regularly shown to increase strength, fat free mass, and muscle morphology with concurrent heavy resistance training more than resistance training alone. Creatine may be of benefit in other modes of exercise such as high-intensity sprints or endurance training. However, it appears that the effects of creatine diminish as the length of time spent exercising increases. Even though not all individuals respond similarly to creatine supplementation, it is generally accepted that its supplementation increases creatine storage and promotes a faster regeneration of adenosine triphosphate between high intensity exercises. These improved outcomes will increase performance and promote greater training adaptations. More recent research suggests that creatine supplementation in amounts of 0.1 g/kg of body weight combined with resistance training improves training adaptations at a cellular and sub-cellular level. Finally, although presently ingesting creatine as an oral supplement is considered safe and ethical, the perception of safety cannot be guaranteed, especially when administered for long period of time to different populations (athletes, sedentary, patient, active, young or elderly). PMID:22817979

Mortality in former Olympic athletes: retrospective cohort analysis

PubMed Central

Zwiers, R; Zantvoord, F W A; van Bodegom, D; van der Ouderaa, F J G; Westendorp, R G J

2012-01-01

Objective To assess the mortality risk in subsequent years (adjusted for year of birth, nationality, and sex) of former Olympic athletes from disciplines with different levels of exercise intensity. Design Retrospective cohort study. Setting Former Olympic athletes. Participants 9889 athletes (with a known age at death) who participated in the Olympic Games between 1896 and 1936, representing 43 types of disciplines with different levels of cardiovascular, static, and dynamic intensity exercise; high or low risk of bodily collision; and different levels of physical contact. Main outcome measure All cause mortality. Results Hazard ratios for mortality among athletes from disciplines with moderate cardiovascular intensity (1.01, 95% confidence interval 0.96 to 1.07) or high cardiovascular intensity (0.98, 0.92 to 1.04) were similar to those in athletes from disciplines with low cardiovascular intensity. The underlying static and dynamic components in exercise intensity showed similar non-significant results. Increased mortality was seen among athletes from disciplines with a high risk of bodily collision (hazard ratio 1.11, 1.06 to 1.15) and with high levels of physical contact (1.16, 1.11 to 1.22). In a multivariate analysis, the effect of high cardiovascular intensity remained similar (hazard ratio 1.05, 0.89 to 1.25); the increased mortality associated with high physical contact persisted (hazard ratio 1.13, 1.06 to 1.21), but that for bodily collision became non-significant (1.03, 0.98 to 1.09) as a consequence of its close relation with physical contact. Conclusions Among former Olympic athletes, engagement in disciplines with high intensity exercise did not bring a survival benefit compared with disciplines with low intensity exercise. Those who engaged in disciplines with high levels of physical contact had higher mortality than other Olympians later in life. PMID:23241269

Long-term effectiveness and cost-effectiveness of high versus low-to-moderate intensity resistance and endurance exercise interventions among cancer survivors.

PubMed

Kampshoff, C S; van Dongen, J M; van Mechelen, W; Schep, G; Vreugdenhil, A; Twisk, J W R; Bosmans, J E; Brug, J; Chinapaw, M J M; Buffart, Laurien M

2018-06-01

This study aimed to evaluate the long-term effectiveness and cost-effectiveness of high intensity (HI) versus low-to-moderate intensity (LMI) exercise on physical fitness, fatigue, and health-related quality of life (HRQoL) in cancer survivors. Two hundred seventy-seven cancer survivors participated in the Resistance and Endurance exercise After ChemoTherapy (REACT) study and were randomized to 12 weeks of HI (n = 139) or LMI exercise (n = 138) that had similar exercise types, durations, and frequencies, but different intensities. Measurements were performed at baseline (4-6 weeks after primary treatment), and 12 (i.e., short term) and 64 (i.e., longer term) weeks later. Outcomes included cardiorespiratory fitness, muscle strength, self-reported fatigue, HRQoL, quality-adjusted life years (QALYs) and societal costs. Linear mixed models were conducted to study (a) differences in effects between HI and LMI exercise at longer term, (b) within-group changes from short term to longer term, and (c) the cost-effectiveness from a societal perspective. At longer term, intervention effects on role (β = 5.9, 95% CI = 0.5; 11.3) and social functioning (β = 5.7, 95%CI = 1.7; 9.6) were larger for HI compared to those for LMI exercise. No significant between-group differences were found for physical fitness and fatigue. Intervention-induced improvements in cardiorespiratory fitness and HRQoL were maintained between weeks 12 and 64, but not for fatigue. From a societal perspective, the probability that HI was cost-effective compared to LMI exercise was 0.91 at 20,000€/QALY and 0.95 at 52,000€/QALY gained, mostly due to significant lower healthcare costs in HI exrcise. At longer term, we found larger intervention effects on role and social functioning for HI than for LMI exercise. Furthermore, HI exercise was cost-effective with regard to QALYs compared to LMI exercise. This study is registered at the Netherlands Trial Register [NTR2153 [ http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=2153

Blood lactate clearance after maximal exercise depends on active recovery intensity.

PubMed

Devlin, J; Paton, B; Poole, L; Sun, W; Ferguson, C; Wilson, J; Kemi, O J

2014-06-01

High-intensity exercise is time-limited by onset of fatigue, marked by accumulation of blood lactate. This is accentuated at maximal, all-out exercise that rapidly accumulates high blood lactate. The optimal active recovery intensity for clearing lactate after such maximal, all-out exercise remains unknown. Thus, we studied the intensity-dependence of lactate clearance during active recovery after maximal exercise. We constructed a standardized maximal, all-out treadmill exercise protocol that predictably lead to voluntary exhaustion and blood lactate concentration>10 mM. Next, subjects ran series of all-out bouts that increased blood lactate concentration to 11.5±0.2 mM, followed by recovery exercises ranging 0% (passive)-100% of the lactate threshold. Repeated measurements showed faster lactate clearance during active versus passive recovery (P<0.01), and that active recovery at 60-100% of lactate threshold was more efficient for lactate clearance than lower intensity recovery (P<0.05). Active recovery at 80% of lactate threshold had the highest rate of and shortest time constant for lactate clearance (P<0.05), whereas the response during the other intensities was graded (100%=60%>40%>passive recovery, P<0.05). Active recovery after maximal all-out exercise clears accumulated blood lactate faster than passive recovery in an intensity-dependent manner, with maximum clearance occurring at active recovery of 80% of lactate threshold.

Long-term lifestyle intervention with optimized high-intensity interval training improves body composition, cardiometabolic risk, and exercise parameters in patients with abdominal obesity.

PubMed

Gremeaux, Vincent; Drigny, Joffrey; Nigam, Anil; Juneau, Martin; Guilbeault, Valérie; Latour, Elise; Gayda, Mathieu

2012-11-01

The aim of this study was to study the impact of a combined long-term lifestyle and high-intensity interval training intervention on body composition, cardiometabolic risk, and exercise tolerance in overweight and obese subjects. Sixty-two overweight and obese subjects (53.3 ± 9.7 yrs; mean body mass index, 35.8 ± 5 kg/m(2)) were retrospectively identified at their entry into a 9-mo program consisting of individualized nutritional counselling, optimized high-intensity interval exercise, and resistance training two to three times a week. Anthropometric measurements, cardiometabolic risk factors, and exercise tolerance were measured at baseline and program completion. Adherence rate was 97%, and no adverse events occurred with high-intensity interval exercise training. Exercise training was associated with a weekly energy expenditure of 1582 ± 284 kcal. Clinically and statistically significant improvements were observed for body mass (-5.3 ± 5.2 kg), body mass index (-1.9 ± 1.9 kg/m(2)), waist circumference (-5.8 ± 5.4 cm), and maximal exercise capacity (+1.26 ± 0.84 metabolic equivalents) (P < 0.0001 for all parameters). Total fat mass and trunk fat mass, lipid profile, and triglyceride/high-density lipoprotein ratio were also significantly improved (P < 0.0001). At program completion, the prevalence of metabolic syndrome was reduced by 32.5% (P < 0.05). Independent predictors of being a responder to body mass and waist circumference loss were baseline body mass index and resting metabolic rate; those for body mass index decrease were baseline waist circumference and triglyceride/high-density lipoprotein cholesterol ratio. A long-term lifestyle intervention with optimized high-intensity interval exercise improves body composition, cardiometabolic risk, and exercise tolerance in obese subjects. This intervention seems safe, efficient, and well tolerated and could improve adherence to exercise training in this population.

Exercise improves behavioral, neurocognitive, and scholastic performance in children with attention-deficit/hyperactivity disorder.

PubMed

Pontifex, Matthew B; Saliba, Brian J; Raine, Lauren B; Picchietti, Daniel L; Hillman, Charles H

2013-03-01

To examine the effect of a single bout of moderate-intensity aerobic exercise on preadolescent children with attention-deficit/hyperactivity disorder (ADHD) using objective measures of attention, brain neurophysiology, and academic performance. Using a within-participants design, task performance and event-related brain potentials were assessed while participants performed an attentional-control task following a bout of exercise or seated reading during 2 separate, counterbalanced sessions. Following a single 20-minute bout of exercise, both children with ADHD and healthy match control children exhibited greater response accuracy and stimulus-related processing, with the children with ADHD also exhibiting selective enhancements in regulatory processes, compared with after a similar duration of seated reading. In addition, greater performance in the areas of reading and arithmetic were observed following exercise in both groups. These findings indicate that single bouts of moderately intense aerobic exercise may have positive implications for aspects of neurocognitive function and inhibitory control in children with ADHD. Copyright © 2013 Mosby, Inc. All rights reserved.

Effects of exercise intensity and duration on nocturnal heart rate variability and sleep quality.

PubMed

Myllymäki, Tero; Rusko, Heikki; Syväoja, Heidi; Juuti, Tanja; Kinnunen, Marja-Liisa; Kyröläinen, Heikki

2012-03-01

Acute physical exercise may affect cardiac autonomic modulation hours or even days during the recovery phase. Although sleep is an essential recovery period, the information on nocturnal autonomic modulation indicated by heart rate variability (HRV) after different exercises is mostly lacking. Therefore, this study investigated the effects of exercise intensity and duration on nocturnal HR, HRV, HR, and HRV-based relaxation, as well as on actigraphic and subjective sleep quality. Fourteen healthy male subjects (age 36 ± 4 years, maximal oxygen uptake 49 ± 4 ml/kg/min) performed five different running exercises on separate occasions starting at 6 p.m. with HR guidance at home. The effect of intensity was studied with 30 min of exercises at intensities corresponding to HR level at 45% (easy), 60% (moderate) and 75% (vigorous) of their maximal oxygen uptake. The effect of duration was studied with 30, 60, and 90 min of moderate exercises. Increased exercise intensity elevated nocturnal HR compared to control day (p < 0.001), but it did not affect nocturnal HRV. Nocturnal HR was greater after the day with 90- than 30- or 60-min exercises (p < 0.01) or control day (p < 0.001). Nocturnal HRV was lower after the 90-min exercise day compared to control day (p < 0.01). Neither exercise intensity nor duration had any impact on actigraphic or subjective sleep quality. The results suggest that increased exercise intensity and/or duration cause delayed recovery of nocturnal cardiac autonomic modulation, although long exercise duration was needed to induce changes in nocturnal HRV. Increased exercise intensity or duration does not seem to disrupt sleep quality.

The anaerobic threshold: over-valued or under-utilized? A novel concept to enhance lipid optimization!

PubMed

Connolly, Declan A J

2012-09-01

The purpose of this article is to assess the value of the anaerobic threshold for use in clinical populations with the intent to improve exercise adaptations and outcomes. The anaerobic threshold is generally poorly understood, improperly used, and poorly measured. It is rarely used in clinical settings and often reserved for athletic performance testing. Increased exercise participation within both clinical and other less healthy populations has increased our attention to optimizing exercise outcomes. Of particular interest is the optimization of lipid metabolism during exercise in order to improve numerous conditions such as blood lipid profile, insulin sensitivity and secretion, and weight loss. Numerous authors report on the benefits of appropriate exercise intensity in optimizing outcomes even though regulation of intensity has proved difficult for many. Despite limited use, selected exercise physiology markers have considerable merit in exercise-intensity regulation. The anaerobic threshold, and other markers such as heart rate, may well provide a simple and valuable mechanism for regulating exercising intensity. The use of the anaerobic threshold and accurate target heart rate to regulate exercise intensity is a valuable approach that is under-utilized across populations. The measurement of the anaerobic threshold can be simplified to allow clients to use nonlaboratory measures, for example heart rate, in order to self-regulate exercise intensity and improve outcomes.

Comparison of Acute Physiological and Psychological Responses Between Moderate Intensity Continuous Exercise and three Regimes of High Intensity Training.

PubMed

Green, Nicole; Wertz, Timothy; LaPorta, Zachary; Mora, Adam; Serbas, Jasmine; Astorino, Todd A

2017-07-19

High intensity interval training (HIIT) elicits similar physiological adaptations as moderate intensity continuous training (MICT) despite less time commitment. However, there is debate whether HIIT is more aversive than MICT. This study compared physiological and perceptual responses between MICT and three regimes of HIIT. Nineteen active adults (age = 24.0 ± 3.3 yr) unfamiliar with HIIT initially performed ramp exercise to exhaustion to measure maximal oxygen uptake (VO2 max) and determine workload for subsequent sessions, whose order was randomized. Sprint interval training (SIT) consisted of six 20 s bouts of "all-out" cycling at 140% of maximum watts (Wmax). Low volume (HIITLV) and high volume HIIT (HIITHV) consisted of eight 60 s bouts at 85% Wmax and six 2 min bouts at 70% Wmax, respectively. MICT consisted of 25 min at 40% Wmax. Across regimes, work was not matched. Heart rate, VO2, blood lactate concentration (BLa), affect, and rating of perceived exertion (RPE) were assessed during exercise. Ten minutes post-exercise, Physical Activity Enjoyment (PACES) was measured via a survey. Results revealed significantly higher (p<0.05) VO2, heart rate, BLa, and RPE in SIT, HIITLV, and HIITHV versus MICT. Despite a decline in affect during exercise (p<0.01) and significantly lower affect (p<0.05) during all HIIT regimes versus MICT at 50, 75, and 100 % of session duration, PACES was similar across regimes (p=0.65) although it was higher in women (p=0.03). Findings from healthy adults unaccustomed to interval training demonstrate that HIIT and SIT are perceived as enjoyable as MICT despite being more aversive.

[Effects of high intensity interval training on blood pressure in hypertensive subjects].

PubMed

Olea, María Angélica; Mancilla, Rodrigo; Martínez, Sergio; Díaz, Erik

2017-09-01

Exercise training may reduce blood pressure. To determine the effects of a high intensity interval training (HIIT) exercise protocol on systolic and diastolic blood pressure in hypertensive subjects. Eleven men and 27 women aged 46.4 ± 9.8 years were divided in two groups according to their blood pressure. Sixteen were classified as normotensive and 22 as hypertensive. All attended an exercise program with 3 sessions per week for a total of 24 sessions. Each session consisted of one minute of intense exercise performed on a stationary bike, followed by an inactive pause lasting two minutes. This cycle was repeated 10 times and it was thus called 1 * 2 * 10. Blood pressure, weight (kg) and body fat were assessed. In the hypertensive group, there was a significant reduction in systolic blood pressure from 145.4 ± 9.0 to 118.3 ± 15.6 mm Hg (p < 0.05). No significant change was observed in diastolic blood pressure (84.9 ± 3.9 and 85.8 ± 17.6 mmHg. Thus, there was a mean reduction in systolic pressure of 27. 7 ± 18.9 mmHg. Therefore, 73% of patients achieved systolic pressures within normal range, without medication. The 1 * 2 * 10 exercise method is effective to improve and restore normal blood pressure in persons with hypertension in a period of two months and 24 sessions.

Cardiorespiratory fitness modulates the acute flow-mediated dilation response following high-intensity but not moderate-intensity exercise in elderly men.

PubMed

Bailey, Tom G; Perissiou, Maria; Windsor, Mark; Russell, Fraser; Golledge, Jonathan; Green, Daniel J; Askew, Christopher D

2017-05-01

Impaired endothelial function is observed with aging and in those with low cardiorespiratory fitness (V̇o 2peak ). Improvements in endothelial function with exercise training are somewhat dependent on the intensity of exercise. While the acute stimulus for this improvement is not completely understood, it may, in part, be due to the flow-mediated dilation (FMD) response to acute exercise. We examined the hypothesis that exercise intensity alters the brachial (systemic) FMD response in elderly men and is modulated by V̇o 2peak Forty-seven elderly men were stratified into lower (V̇o 2peak = 24.3 ± 2.9 ml·kg -1 ·min -1 ; n = 27) and higher fit groups (V̇o 2peak = 35.4 ± 5.5 ml·kg -1 ·min -1 ; n = 20) after a test of cycling peak power output (PPO). In randomized order, participants undertook moderate-intensity continuous exercise (MICE; 40% PPO) or high-intensity interval cycling exercise (HIIE; 70% PPO) or no-exercise control. Brachial FMD was assessed at rest and 10 and 60 min after exercise. FMD increased after MICE in both groups {increase of 0.86% [95% confidence interval (CI), 0.17-1.56], P = 0.01} and normalized after 60 min. In the lower fit group, FMD was reduced after HIIE [reduction of 0.85% (95% CI, 0.12-1.58), P = 0.02] and remained decreased at 60 min. In the higher fit group, FMD was unchanged immediately after HIIE and increased after 60 min [increase of 1.52% (95% CI, 0.41-2.62), P < 0.01, which was correlated with V̇o 2peak , r = 0.41; P < 0.01]. In the no-exercise control, FMD was reduced in both groups after 60 min ( P = 0.05). Exercise intensity alters the acute FMD response in elderly men and V̇o 2peak modulates the FMD response following HIIE but not MICE. The sustained decrease in FMD in the lower fit group following HIIE may represent a signal for vascular adaptation or endothelial fatigue. NEW & NOTEWORTHY This study is the first to show that moderate-intensity continuous cycling exercise increased flow-mediated dilation (FMD) transiently before normalization of FMD after 1 h, irrespective of cardiorespiratory fitness level in elderly men. Interestingly, we show increased FMD after high-intensity cycling exercise in higher fit men, with a sustained reduction in FMD in lower fit men. The prolonged reduction in FMD after high-intensity cycling exercise may be associated with future vascular adaptation but may also reflect a period of increased cardiovascular risk in lower fit elderly men. Copyright © 2017 the American Physiological Society.

Potential Universal Application of High-intensity Interval Training from Athletes and Sports Lovers to Patients.

PubMed

Azuma, Koichiro; Matsumoto, Hideo

2017-06-25

Recently, high-intensity interval training (HIIT) has received much attention as a promising exercise option not only to improve aerobic fitness, but also to prevent and improve lifestyle-related diseases. Epidemiological studies have shown that the exercise volume, as determined by the product of exercise intensity, duration, and frequency, has been shown to be important for improvements in muscle mitochondrial activity and subsequent improvements in aerobic fitness, insulin sensitivity, and metabolic variables. Therefore, continuous moderate-intensity training has been widely recommended. On the other hand, the main contributor of HIIT to improvements in aerobic fitness and metabolic variables is its high-intensity nature, and many recent studies have shown results favoring HIIT when compared with conventional continuous training, despite its shorter exercise duration and smaller exercise volume. In this review, we aim to show the possible universal application of HIIT in a hospital setting, where athletes, sports lovers, and patients have sought medical advice and have the opportunity to undergo detailed evaluations, including an exercise stress test. For athletes, HIIT is mandatory to achieve further improvements in aerobic fitness. For patients, though higher levels of motivation and careful evaluation are required, the time constraints of HIIT are smaller and both aerobic and resistance training can be expected to yield favorable results because of the high-intensity nature of HIIT.

High intensity interval exercise is an effective alternative to moderate intensity exercise for improving glucose tolerance and insulin sensitivity in adolescent boys.

PubMed

Cockcroft, Emma J; Williams, Craig A; Tomlinson, Owen W; Vlachopoulos, Dimitris; Jackman, Sarah R; Armstrong, Neil; Barker, Alan R

2015-11-01

High-intensity interval exercise (HIIE) may offer a time efficient means to improve health outcomes compared to moderate-intensity exercise (MIE). This study examined the acute effect of HIIE compared to a work-matched bout of MIE on glucose tolerance, insulin sensitivity (IS), resting fat oxidation and exercise enjoyment in adolescent boys. Within-measures design with counterbalanced experimental conditions. Nine boys (14.2 ± 0.4 years) completed three conditions on separate days in a counterbalanced order: (1) HIIE; (2) work matched MIE, both on a cycle ergometer; and (3) rest (CON). An oral glucose tolerance test (OGTT) was performed after exercise or rest and the area under curve (AUC) responses for plasma [glucose] and [insulin] were calculated, and IS estimated (Cederholm index). Energy expenditure and fat oxidation were measured following the OGTT using indirect calorimetry. Exercise enjoyment was assessed using the Physical Activity Enjoyment Scale. The incremental AUC (iAUC) for plasma [glucose] was reduced following both MIE (-23.9%, P = 0.013, effect size [ES] = -0.64) and HIIE (-28.9%, P=0.008, ES = -0.84) compared to CON. The iAUC for plasma [insulin] was lower for HIIE (-24.2%, P = 0.021, ES = -0.71) and MIE (-29.1%, P = 0.012, ES = -0.79) compared to CON. IS increased by 11.2% after HIIE (P = 0.03, ES = 0.76) and 8.4% after MIE (P = 0.10, ES = 0.58). There was a trend for an increase in fat oxidation following HIIE (P = 0.097, ES = 0.70). Both HIIE and MIE were rated as equally enjoyable (P > 0.05, ES < 0.01). A single bout of time efficient HIIE is an effective alternative to MIE for improving glucose tolerance and IS in adolescent boys immediately after exercise. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Changes of heart rate variability and prefrontal oxygenation during Tai Chi practice versus arm ergometer cycling.

PubMed

Lu, Xi; Hui-Chan, Christina Wan-Ying; Tsang, William Wai-Nam

2016-11-01

[Purpose] Exercise has been shown to improve cardiovascular fitness and cognitive function. Whether the inclusion of mind over exercise would increase parasympathetic control of the heart and brain activities more than general exercise at a similar intensity is not known. The aim of this study was to compare the effects of Tai Chi (mind-body exercise) versus arm ergometer cycling (body-focused exercise) on the heart rate variability and prefrontal oxygenation level. [Subjects and Methods] A Tai Chi master was invited to perform Tai Chi and arm ergometer cycling with similar exercise intensity on two separate days. Heart rate variability and prefrontal oxyhemoglobin levels were measured continuously by a RR recorder and near-infrared spectroscopy, respectively. [Results] During Tai Chi exercise, spectral analysis of heart rate variability demonstrated a higher high-frequency power as well as a lower low-frequency/high-frequency ratio than during ergometer cycling, suggesting increased parasympathetic and decreased sympathetic control of the heart. Also, prefrontal oxyhemoglobin and total hemoglobin levels were higher than those during arm ergometer exercise. [Conclusion] These findings suggest that increased parasympathetic control of the heart and prefrontal activities may be associated with Tai Chi practice. Having a "mind" component in Tai Chi could be more beneficial for older adults' cardiac health and cognitive function than body-focused ergometer cycling.

Post-Plyometric Exercise Hypotension and Heart Rate in Normotensive Individuals: Influence of Exercise Intensity

PubMed Central

Arazi, Hamid; Asadi, Abbas; Rahimzadeh, Mehdi; Moradkhani, Amir-Hossein

2013-01-01

Purpose The purpose of this study was to compare the effects of high, moderate and low intensity plyometric exercise on the post-exercise systolic and diastolic blood pressure and heart rate responses. Methods Ten healthy normotensive men (age, 21.1±0.9 years; height, 175.8±6 cm; and body mass, 69.1±13.6 kg) volunteered to participate in this study and were evaluated for three non-consecutive days in depth jump exercise from 20-cm box (low intensity [LI]), 40-cm box (moderate intensity [MI]) and 60-cm box (high intensity [HI]) for 5 sets of 20 repetitions. After each exercise session, systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were measured every 10 min for a period of 90 min. Results No significant differences were observed among post-exercise SBP, DBP and HR when the protocols (LI, MI and HI) were compared. The LI and HI protocols showed greater reduction in SBP at 40th-70th min of post-exercise (~9%), whereas the LI and MI protocols indicated greater reduction in DBP at 10th-50th min of post exercise (~10%). In addition, the change in the DBP for HI was not significant and the increases in the HR were similar for all intensities. Conclusion It can be concluded that a plyometric exercise (PE) can reduce SBP and DBP post-exercise and therefore we can say that PE has significant effects for reducing BP and HR or post-exercise hypotension. PMID:24799997

High Intensity Interval Training for Maximizing Health Outcomes.

PubMed

Karlsen, Trine; Aamot, Inger-Lise; Haykowsky, Mark; Rognmo, Øivind

Regular physical activity and exercise training are important actions to improve cardiorespiratory fitness and maintain health throughout life. There is solid evidence that exercise is an effective preventative strategy against at least 25 medical conditions, including cardiovascular disease, stroke, hypertension, colon and breast cancer, and type 2 diabetes. Traditionally, endurance exercise training (ET) to improve health related outcomes has consisted of low- to moderate ET intensity. However, a growing body of evidence suggests that higher exercise intensities may be superior to moderate intensity for maximizing health outcomes. The primary objective of this review is to discuss how aerobic high-intensity interval training (HIIT) as compared to moderate continuous training may maximize outcomes, and to provide practical advices for successful clinical and home-based HIIT. Copyright © 2017. Published by Elsevier Inc.

Psychophysiological effects of music on acute recovery from high-intensity interval training.

PubMed

Jones, Leighton; Tiller, Nicholas B; Karageorghis, Costas I

2017-03-01

Numerous studies have examined the multifarious effects of music applied during exercise but few have assessed the efficacy of music as an aid to recovery. Music might facilitate physiological recovery via the entrainment of respiratory rhythms with music tempo. High-intensity exercise training is not typically associated with positive affective responses, and thus ways of assuaging negative affect warrant further exploration. This study assessed the psychophysiological effects of music on acute recovery and prevalence of entrainment in between bouts of high-intensity exercise. Thirteen male runners (M age =20.2±1.9years; BMI=21.7±1.7; V̇O 2 max=61.6±6.1mL·kg·min -1 ) completed three exercise sessions comprising 5×5-min bouts of high-intensity intervals interspersed with 3-min periods of passive recovery. During recovery, participants were administered positively-valenced music of a slow-tempo (55-65bpm), fast-tempo (125-135bpm), or a no-music control. A range of measures including affective responses, RPE, cardiorespiratory indices (gas exchange and pulmonary ventilation), and music tempo-respiratory entrainment were recorded during exercise and recovery. Fast-tempo, positively-valenced music resulted in higher Feeling Scale scores throughout recovery periods (p<0.01, η p 2 =0.38). There were significant differences in HR during initial recovery periods (p<0.05, η p 2 =0.16), but no other music-moderated differences in cardiorespiratory responses. In conclusion, fast-tempo, positively-valenced music applied during recovery periods engenders a more pleasant experience. However, there is limited evidence that music expedites cardiorespiratory recovery in between bouts of high-intensity exercise. These findings have implications for athletic training strategies and individuals seeking to make high-intensity exercise sessions more pleasant. Copyright © 2016 Elsevier Inc. All rights reserved.

International society of sports nutrition position stand: caffeine and performance

PubMed Central

2010-01-01

Position Statement: The position of The Society regarding caffeine supplementation and sport performance is summarized by the following seven points: 1.) Caffeine is effective for enhancing sport performance in trained athletes when consumed in low-to-moderate dosages (~3-6 mg/kg) and overall does not result in further enhancement in performance when consumed in higher dosages (≥ 9 mg/kg). 2.) Caffeine exerts a greater ergogenic effect when consumed in an anhydrous state as compared to coffee. 3.) It has been shown that caffeine can enhance vigilance during bouts of extended exhaustive exercise, as well as periods of sustained sleep deprivation. 4.) Caffeine is ergogenic for sustained maximal endurance exercise, and has been shown to be highly effective for time-trial performance. 5.) Caffeine supplementation is beneficial for high-intensity exercise, including team sports such as soccer and rugby, both of which are categorized by intermittent activity within a period of prolonged duration. 6.) The literature is equivocal when considering the effects of caffeine supplementation on strength-power performance, and additional research in this area is warranted. 7.) The scientific literature does not support caffeine-induced diuresis during exercise, or any harmful change in fluid balance that would negatively affect performance. PMID:20205813

The effects of a single bout of exercise on motor memory interference in the trained and untrained hemisphere.

PubMed

Lauber, Benedikt; Franke, Steffen; Taube, Wolfgang; Gollhofer, Albert

2017-04-07

Increasing evidence suggests that cardiovascular exercise has positive effects on motor memory consolidation. In this study, we investigated whether a single session of high-intensity interval training (HIIT) mitigates the effects of practicing an interfering motor task. Furthermore, learning and interference effects were assessed in the actively trained and untrained limb as it is known that unilateral motor learning can cause bilateral adaptations. Subjects performed a ballistic training and then the HIIT either before (HIIT_before) or after (HIIT_after) practicing an interfering accuracy task (AT). The control group (No_HIIT) did not participate in the HIIT but rested instead. Performance in the ballistic task (BT) was tested before and after the ballistic training, after the exercise and practice of the AT and 24h later. After ballistic training, all groups showed comparable increases in performance in the trained and untrained limb. Despite the practice of the AT, HIIT_before maintained their BT performance after the high-intensity interval training whereas HIIT_after (trend) & No_HIIT showed prominent interference effects. After 24h, HIIT_before still did not show any interference effects but further improved ballistic motor performance. HIIT_after counteracted the interference resulting in a comparable BT performance after 24h than directly after the ballistic training while No_HIIT had a significantly lower BT performance in the retention test. The results were similar in the trained and untrained limb. The current results imply that a single session of cardiovascular exercise can prevent motor interference in the trained and untrained hemisphere. Overall learning was best, and interference least, when HIIT was performed before the interfering motor task. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

What are the Physiological Mechanisms for Post-Exercise Cold Water Immersion in the Recovery from Prolonged Endurance and Intermittent Exercise?

PubMed

Ihsan, Mohammed; Watson, Greig; Abbiss, Chris R

2016-08-01

Intense training results in numerous physiological perturbations such as muscle damage, hyperthermia, dehydration and glycogen depletion. Insufficient/untimely restoration of these physiological alterations might result in sub-optimal performance during subsequent training sessions, while chronic imbalance between training stress and recovery might lead to overreaching or overtraining syndrome. The use of post-exercise cold water immersion (CWI) is gaining considerable popularity among athletes to minimize fatigue and accelerate post-exercise recovery. CWI, through its primary ability to decrease tissue temperature and blood flow, is purported to facilitate recovery by ameliorating hyperthermia and subsequent alterations to the central nervous system (CNS), reducing cardiovascular strain, removing accumulated muscle metabolic by-products, attenuating exercise-induced muscle damage (EIMD) and improving autonomic nervous system function. The current review aims to provide a comprehensive and detailed examination of the mechanisms underpinning acute and longer term recovery of exercise performance following post-exercise CWI. Understanding the mechanisms will aid practitioners in the application and optimisation of CWI strategies to suit specific recovery needs and consequently improve athletic performance. Much of the literature indicates that the dominant mechanism by which CWI facilitates short term recovery is via ameliorating hyperthermia and consequently CNS mediated fatigue and by reducing cardiovascular strain. In contrast, there is limited evidence to support that CWI might improve acute recovery by facilitating the removal of muscle metabolites. CWI has been shown to augment parasympathetic reactivation following exercise. While CWI-mediated parasympathetic reactivation seems detrimental to high-intensity exercise performance when performed shortly after, it has been shown to be associated with improved longer term physiological recovery and day to day training performances. The efficacy of CWI for attenuating the secondary effects of EIMD seems dependent on the mode of exercise utilised. For instance, CWI application seems to demonstrate limited recovery benefits when EIMD was induced by single-joint eccentrically biased contractions. In contrast, CWI seems more effective in ameliorating effects of EIMD induced by whole body prolonged endurance/intermittent based exercise modalities.

MUSIC TEMPO'S EFFECT ON EXERCISE PERFORMANCE: COMMENT ON DYER AND McKUNE.

PubMed

Nakamura, Priscila Missaki

2015-06-01

Dyer and McKune (2013) stated that music tempo has no influence on performance, physiological, and psychophysical variables in well-trained cyclists during high intensity endurance tasks. However, there are important limitations in the methodology of the study. The participants' music preferences and tempo change were not well measured. It is not possible to affirm that music tempo does not influence athletes' performance. Potential areas of future research include: (a) use of instruments to assess the qualities of music; (b) standardizing music of tempo according to exercise type (e.g., running, cycling, etc.); (c) considering training level of the participants (i.e., athletes and non-athletes); and (d) use of instruments to assess concentration during exercise.

Effect of high-intensity intermittent swimming training on fatty acid oxidation enzyme activity in rat skeletal muscle.

PubMed

Terada, Shin; Tabata, Izumi; Higuchi, Mitsuru

2004-02-01

We previously reported that high-intensity exercise training significantly increased citrate synthase (CS) activity, a marker of oxidative enzyme, in rat skeletal muscle to a level equaling that attained after low-intensity prolonged exercise training (Terada et al., J Appl Physiol 90: 2019-2024, 2001). Since mitochondrial oxidative enzymes and fatty acid oxidation (FAO) enzymes are often increased simultaneously, we assessed the effect of high-intensity intermittent swimming training on FAO enzyme activity in rat skeletal muscle. Male Sprague-Dawley rats (3 to 4 weeks old) were assigned to a 10-day period of high-intensity intermittent exercise training (HIT), low-intensity prolonged exercise training (LIT), or sedentary control conditions. In the HIT group, the rats repeated fourteen 20 s swimming sessions with a weight equivalent to 14-16% of their body weight. Between the exercise sessions, a 10 s pause was allowed. Rats in the LIT group swam 6 h/day in two 3 h sessions separated by 45 min of rest. CS activity in the triceps muscle of rats in the HIT and LIT groups was significantly higher than that in the control rats by 36 and 39%, respectively. Furthermore, 3-beta hydroxyacyl-CoA dehydrogenase (HAD) activity, an important enzyme in the FAO pathway in skeletal muscle, was higher in the two training groups than in the control rats (HIT: 100%, LIT: 88%). No significant difference in HAD activity was observed between the two training groups. In conclusion, the present investigation demonstrated that high-intensity intermittent swimming training elevated FAO enzyme activity in rat skeletal muscle to a level similar to that attained after 6 h of low-intensity prolonged swimming exercise training.

Post-exercise ingestion of a unique, high molecular weight glucose polymer solution improves performance during a subsequent bout of cycling exercise.

PubMed

Stephens, Francis B; Roig, Marc; Armstrong, Gerald; Greenhaff, Paul L

2008-01-15

The aim of the present study was to determine the effect of post-exercise ingestion of a unique, high molecular weight glucose polymer solution, known to augment gastric emptying and post-exercise muscle glycogen re-synthesis, on performance during a subsequent bout of intense exercise. On three randomized visits, eight healthy men cycled to exhaustion at 73.0% (s = 1.3) maximal oxygen uptake (90 min, s = 15). Immediately after this, participants consumed a one-litre solution containing sugar-free flavoured water (control), 100 g of a low molecular weight glucose polymer or 100 g of a very high molecular weight glucose polymer, and rested on a bed for 2 h. After recovery, a 15-min time-trial was performed on a cycle ergometer, during which work output was determined. Post-exercise ingestion of the very high molecular weight glucose polymer solution resulted in faster and greater increases in blood glucose (P < 0.001) and serum insulin (P < 0.01) concentrations than the low molecular weight glucose polymer solution, and greater work output during the 15-min time-trial (164.1 kJ, s = 21.1) than both the sugar-free flavoured water (137.5 kJ, s = 24.2; P < 0.05) and the low molecular weight glucose polymer (149.4 kJ, s = 21.8; P < 0.05) solutions. These findings could be of practical importance for athletes wishing to optimize performance by facilitating rapid re-synthesis of the muscle glycogen store during recovery following prolonged sub-maximal exercise.

Virtual reality bringing a new reality to postthoracotomy lung cancer patients via a home-based exercise intervention targeting fatigue while undergoing adjuvant treatment.

PubMed

Hoffman, Amy J; Brintnall, Ruth Ann; Brown, Jean K; von Eye, Alexander; Jones, Lee W; Alderink, Gordon; Ritz-Holland, Deborah; Enter, Mark; Patzelt, Lawrence H; VanOtteren, Glenn M

2014-01-01

Little is known about rehabilitation for postthoracotomy non-small cell lung cancer (NSCLC) patients. This research uses a perceived self-efficacy-enhancing light-intensity exercise intervention targeting a priority symptom, cancer-related fatigue (CRF), for postthoracotomy NSCLC patients. This article reports on phase II of a 2-phase study. Phase I focused on initiation and tolerance of exercise during the 6 weeks immediately after thoracotomy, whereas phase II addressed maintenance of exercise for an additional 10 weeks including participants initiating and completing chemotherapy and/or radiation therapy. The objective of this study was to investigate the feasibility, acceptability, and preliminary efficacy of an exercise intervention for postthoracotomy NSCLC patients to include those initiating and completing adjuvant therapy. A single-arm design composed of 7 participants postthoracotomy for NSCLC performed light-intensity exercises using an efficacy-enhancing virtual-reality approach using the Nintendo Wii Fit Plus. Despite most participants undergoing chemotherapy and/or radiation therapy, participants adhered to the intervention at a rate of 88% with no adverse events while giving the intervention high acceptability scores on conclusion. Likewise, participants' CRF scores improved from initiation through the conclusion of the intervention with perceived self-efficacy for walking at a light intensity continuously for 60 minutes, improving significantly upon conclusion over presurgery values. Postthoracotomy NSCLC patients maintained exercise for an additional 10 weeks while undergoing adjuvant therapy showing rehabilitation potential because the exercise intervention was feasible, safe, well tolerated, and highly acceptable showing positive changes in CRF self-management. A randomized controlled trial is needed to further investigate these relationships.

Translation of incremental talk test responses to steady-state exercise training intensity.

PubMed

Lyon, Ellen; Menke, Miranda; Foster, Carl; Porcari, John P; Gibson, Mark; Bubbers, Terresa

2014-01-01

The Talk Test (TT) is a submaximal, incremental exercise test that has been shown to be useful in prescribing exercise training intensity. It is based on a subject's ability to speak comfortably during exercise. This study defined the amount of reduction in absolute workload intensity from an incremental exercise test using the TT to give appropriate absolute training intensity for cardiac rehabilitation patients. Patients in an outpatient rehabilitation program (N = 30) performed an incremental exercise test with the TT given every 2-minute stage. Patients rated their speech comfort after reciting a standardized paragraph. Anything other than a "yes" response was considered the "equivocal" stage, while all preceding stages were "positive" stages. The last stage with the unequivocally positive ability to speak was the Last Positive (LP), and the preceding stages were (LP-1 and LP-2). Subsequently, three 20-minute steady-state training bouts were performed in random order at the absolute workload at the LP, LP-1, and LP-2 stages of the incremental test. Speech comfort, heart rate (HR), and rating of perceived exertion (RPE) were recorded every 5 minutes. The 20-minute exercise training bout was completed fully by LP (n = 19), LP-1 (n = 28), and LP-2 (n = 30). Heart rate, RPE, and speech comfort were similar through the LP-1 and LP-2 tests, but the LP stage was markedly more difficult. Steady-state exercise training intensity was easily and appropriately prescribed at intensity associated with the LP-1 and LP-2 stages of the TT. The LP stage may be too difficult for patients in a cardiac rehabilitation program.

Effect of Short-Term, High-Intensity Exercise on Anaerobic Threshold in Women.

ERIC Educational Resources Information Center

Evans, Blanche W.

This study investigated the effects of a six-week, high-intensity cycling program on anaerobic threshold (AT) in ten women. Subjects trained four days a week using high-intensity interval-type cycle exercises. Workouts included six 4-minute intervals cycling at 85 percent maximal oxygen uptake (VO sub 2 max), separated by 3-minute intervals of…

Effects of exercise amount and intensity on abdominal obesity and glucose tolerance in obese adults: a randomized trial.

PubMed

Ross, Robert; Hudson, Robert; Stotz, Paula J; Lam, Miu

2015-03-03

Exercise reduces obesity and related glucose tolerance, but whether increasing exercise intensity offers additional benefit at fixed exercise amounts is unknown. To determine the separate effects of exercise amount and intensity on abdominal obesity and glucose tolerance. 24-week, single-center, parallel-group trial from 2009 to 2013. (ClinicalTrials.gov: NCT00955071). Kingston, Ontario, Canada. 300 abdominally obese adults. Control (no exercise) (n = 75) or 5 weekly sessions of low-amount, low-intensity exercise (LALI) (180 and 300 kcal/session for women and men, respectively, at 50% of maximum oxygen consumption [V̇o2peak]) (n = 73); high-amount, low-intensity exercise (HALI) (360 and 600 kcal/session, respectively, at 50% of V̇o2peak) (n = 76); or high-amount, high-intensity exercise (HAHI) (360 and 600 kcal/session, respectively, at 75% of V̇o2peak) (n = 76). Daily unsupervised physical activity and sedentary time were measured by accelerometer. Waist circumference and 2-hour glucose level (primary outcomes) and cardiorespiratory fitness and measures of insulin action (secondary measurements). 217 participants (72.3%) completed the intervention. Mean exercise time in minutes per session was 31 (SD, 4.4) for LALI, 58 (SD, 7.6) for HALI, and 40 (SD, 6.2) for HAHI. Daily unsupervised physical activity and sedentary time did not change in any exercise group versus control (P > 0.33). After adjustment for age and sex in a linear mixed model, reductions in waist circumference were greater in the LALI (-3.9 cm [95% CI, -5.6 to -2.3 cm]; P < 0.001), HALI (-4.6 cm [CI, -6.2 to -3.0 cm]; P < 0.001), and HAHI (-4.6 cm [CI, -6.3 to -2.9 cm]; P < 0.001) groups than the control group but did not differ among the exercise groups (P > 0.43). After adjustment for covariates, reductions in 2-hour glucose level were greater in the HAHI group (-0.7 mmol/L [-12.5 mg/dL] [CI, -1.3 to -0.1 mmol/L {-23.5 to -1.5 mg/dL}]; P = 0.027) than the control group but did not differ for the LALI or HALI group versus the control group (P > 0.159). Weight loss was greater in all exercise groups than the control group (P < 0.001); however, reduction in body weight did not differ among the exercise groups (P > 0.182). The clinical importance of reducing 2-hour glucose level in nondiabetic adults remains undetermined. Fixed amounts of exercise independent of exercise intensity resulted in similar reductions in abdominal obesity. Reduction in 2-hour glucose level was restricted to high-intensity exercise.

Skeletal muscle fiber type composition and performance during repeated bouts of maximal, concentric contractions

NASA Technical Reports Server (NTRS)

Colliander, E. B.; Dudley, G. A.; Tesch, P. A.

1988-01-01

Force output and fatigue and recovery patterns were studied during intermittent short-term exercise. 27 men performed three bouts of 30 maximal unilateral knee extensions on 2 different occasions. Blood flow was maintained or occluded during recovery periods (60 s). Blood flow was restricted by inflating a pneumatic cuff placed around the proximal thigh. Muscle biopsies from vastus lateralis were analyzed for identification of fast twitch (FT) and slow twitch (ST) fibers and relative FT area. Peak torque decreased during each bout of exercise and more when blood flow was restricted during recovery. Initial peak torque (IPT) and average peak torque (APT) decreased over the three exercise bouts. This response was 3 fold greater without than with blood flow during recovery. IPT and APT decreased more in individuals with mainly FT fibers than in those with mainly ST fibers. It is suggested that performance during repeated bouts of maximal concentric contractions differs between individuals with different fiber type composition. Specifically, in high intensity, intermittent exercise with emphasis on anaerobic energy release a high FT composition may not necessarily be advantageous for performance.

The effect of exercise mode on the acute response of satellite cells in old men.

PubMed

Nederveen, J P; Joanisse, S; Séguin, C M L; Bell, K E; Baker, S K; Phillips, S M; Parise, G

2015-12-01

A dysregulation of satellite cells may contribute to the progressive loss of muscle mass that occurs with age; however, older adults retain the ability to activate and expand their satellite cell pool in response to exercise. The modality of exercise capable of inducing the greatest acute response is unknown. We sought to characterize the acute satellite cell response following different modes of exercise in older adults. Sedentary older men (n = 22; 67 ± 4 years; 27 ± 2.6 kg*m(-2) ) were randomly assigned to complete an acute bout of either resistance exercise, high-intensity interval exercise on a cycle ergometer or moderate-intensity aerobic exercise. Muscle biopsies were obtained before, 24 and 48 h following each exercise bout. The satellite cell response was analysed using immunofluorescent microscopy of muscle cross sections. Satellite cell expansion associated with type I fibres was observed 24 and 48 h following resistance exercise only (P ˂ 0.05), while no expansion of type II-associated satellite cells was observed in any group. There was a greater number of activated satellite cells 24 h following resistance exercise (pre: 1.3 ± 0.1, 24 h: 4.8 ± 0.5 Pax7 + /MyoD+cells/100 fibres) and high-intensity interval exercise (pre: 0.7 ± 0.3, 24 h: 3.1 ± 0.3 Pax7 + /MyoD+cells/100 fibres) (P ˂ 0.05). The percentage of type I-associated SC co-expressing MSTN was reduced only in the RE group 24 h following exercise (pre: 87 ± 4, 24 h: 57 ± 5%MSTN+ type I SC) (P < 0.001). Although resistance exercise is the most potent exercise type to induce satellite cell pool expansion, high-intensity interval exercise was also more potent than moderate-intensity aerobic exercise in inducing satellite cell activity. © 2015 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

Aerobic Exercise Training in Post-Polio Syndrome: Process Evaluation of a Randomized Controlled Trial

PubMed Central

Voorn, Eric L.; Koopman, Fieke S.; Brehm, Merel A.; Beelen, Anita; de Haan, Arnold; Gerrits, Karin H. L.; Nollet, Frans

2016-01-01

Objective To explore reasons for the lack of efficacy of a high intensity aerobic exercise program in post-polio syndrome (PPS) on cardiorespiratory fitness by evaluating adherence to the training program and effects on muscle function. Design A process evaluation using data from an RCT. Patients Forty-four severely fatigued individuals with PPS were randomized to exercise therapy (n = 22) or usual care (n = 22). Methods Participants in the exercise group were instructed to exercise 3 times weekly for 4 months on a bicycle ergometer (60–70% heart rate reserve). Results The attendance rate was high (median 89%). None of the participants trained within the target heart rate range during >75% of the designated time. Instead, participants exercised at lower intensities, though still around the anaerobic threshold (AT) most of the time. Muscle function did not improve in the exercise group. Conclusion Our results suggest that severely fatigued individuals with PPS cannot adhere to a high intensity aerobic exercise program on a cycle ergometer. Despite exercise intensities around the AT, lower extremity muscle function nor cardiorespiratory fitness improved. Improving the aerobic capacity in PPS is difficult through exercise primarily focusing on the lower extremities, and may require a more individualized approach, including the use of other large muscle groups instead. Trial Registration Netherlands National Trial Register NTR1371 PMID:27419388

Intensive exercise training suppresses testosterone during bed rest

NASA Technical Reports Server (NTRS)

Wade, C. E.; Stanford, K. I.; Stein, T. P.; Greenleaf, J. E.

2005-01-01

Spaceflight and prolonged bed rest (BR) alter plasma hormone levels inconsistently. This may be due, in part, to prescription of heavy exercise as a countermeasure for ameliorating the adverse effects of disuse. The initial project was to assess exercise programs to maintain aerobic performance and leg strength during BR. The present study evaluates the effect of BR and the performance of the prescribed exercise countermeasures on plasma steroid levels. In a 30-day BR study of male subjects, the efficacy of isotonic (ITE, n = 7) or isokinetic exercise (IKE, n = 7) training was evaluated in contrast to no exercise (n = 5). These exercise countermeasures protected aerobic performance and leg strength successfully. BR alone (no-exercise group) did not change steroidogenesis, as assessed by the plasma concentrations of cortisol, progesterone, aldosterone, and free (FT) and total testosterone (TT). In the exercise groups, both FT and TT were decreased (P < 0.05): FT during IKE from 24 +/- 1.7 to 18 +/- 2.0 pg/ml and during ITE from 21 +/- 1.5 to 18 +/- 1 pg/ml, and TT during IKE from 748 +/- 68 to 534 +/- 46 ng/dl and during ITE from 565 +/- 36 to 496 +/- 38 ng/dl. The effect of intensive exercise countermeasures on plasma testosterone was not associated with indexes of overtraining. The reduction in plasma testosterone associated with both the IKE and ITE countermeasures during BR supports our hypothesis that intensive exercise countermeasures may, in part, contribute to changes in plasma steroid concentrations during spaceflight.

Sodium bicarbonate supplementation improves severe-intensity intermittent exercise under moderate acute hypoxic conditions.

PubMed

Deb, Sanjoy K; Gough, Lewis A; Sparks, S Andy; McNaughton, Lars R

2018-03-01

Acute moderate hypoxic exposure can substantially impair exercise performance, which occurs with a concurrent exacerbated rise in hydrogen cation (H + ) production. The purpose of this study was therefore, to alleviate this acidic stress through sodium bicarbonate (NaHCO 3 ) supplementation and determine the corresponding effects on severe-intensity intermittent exercise performance. Eleven recreationally active individuals participated in this randomised, double-blind, crossover study performed under acute normobaric hypoxic conditions (FiO 2 % = 14.5%). Pre-experimental trials involved the determination of time to attain peak bicarbonate anion concentrations ([HCO 3 - ]) following NaHCO 3 ingestion. The intermittent exercise tests involved repeated 60-s work in their severe-intensity domain and 30-s recovery at 20 W to exhaustion. Participants ingested either 0.3 g kg bm -1 of NaHCO 3 or a matched placebo of 0.21 g kg bm -1 of sodium chloride prior to exercise. Exercise tolerance (+ 110.9 ± 100.6 s; 95% CI 43.3-178 s; g = 1.0) and work performed in the severe-intensity domain (+ 5.8 ± 6.6 kJ; 95% CI 1.3-9.9 kJ; g = 0.8) were enhanced with NaHCO 3 supplementation. Furthermore, a larger post-exercise blood lactate concentration was reported in the experimental group (+ 4 ± 2.4 mmol l -1 ; 95% CI 2.2-5.9; g = 1.8), while blood [HCO 3 - ] and pH remained elevated in the NaHCO 3 condition throughout experimentation. In conclusion, this study reported a positive effect of NaHCO 3 under acute moderate hypoxic conditions during intermittent exercise and therefore, may offer an ergogenic strategy to mitigate hypoxic induced declines in exercise performance.

Psychobiological Responses to Preferred and Prescribed Intensity Exercise in Major Depressive Disorder.

PubMed

Meyer, Jacob D; Ellingson, Laura D; Koltyn, Kelli F; Stegner, Aaron J; Kim, Jee-Seon; Cook, Dane B

2016-11-01

Exercise acutely improves mood in major depressive disorder (MDD). However, it is unknown whether benefits differ depending on whether exercise intensity is self-selected or prescribed. This study aimed to compare psychological and biological responses to preferred and prescribed steady-state exercise intensities to a patient-selected preferred intensity. Female adults (N = 24, age = 38.6 ± 14.0 yr) diagnosed with MDD completed four 30-min sessions of cycling exercise at three prescribed intensities (RPE of 11, 13, and 15) and one session with a self-selected intensity (preferred). Order was randomized and counterbalanced. Depressed mood (DM) was evaluated before, 10 min, and 30 min postexercise using the Profile of Mood States. Serum brain-derived neurotrophic factor (BDNF) was measured before and within 10 min postexercise. Changes in BDNF and DM for the preferred session were compared with the following prescribed sessions: 1) performed at the most similar intensity (matched on RPE; closest) and 2) with the greatest improvement in DM (greatest). Compared with the preferred session, improvement in DM was significantly larger after the greatest session (30 min postexercise: -11.8 ± 7.4 vs -3.4 ± 4.8), and the BDNF response was significantly greater after the closest session (5.4 ± 6.9 vs -1.4 ± 9.8 ng·mL). Permitting patients to select their own exercise intensity did not maximize improvements in mood. Further, preferred intensity exercise was also associated with a smaller BDNF response. Overall, the results suggest that exercise undertaken to improve mood should be prescribed on an individual basis in MDD and not necessarily based on the patient's preferred intensity. Clinicians, psychologists, and other practitioners should consider providing clear exercise intensity recommendations for symptom management in depression rather than allowing patients to self-select their intensity.

Military Applicability of Interval Training for Health and Performance.

PubMed

Gibala, Martin J; Gagnon, Patrick J; Nindl, Bradley C

2015-11-01

Militaries from around the globe have predominantly used endurance training as their primary mode of aerobic physical conditioning, with historical emphasis placed on the long distance run. In contrast to this traditional exercise approach to training, interval training is characterized by brief, intermittent bouts of intense exercise, separated by periods of lower intensity exercise or rest for recovery. Although hardly a novel concept, research over the past decade has shed new light on the potency of interval training to elicit physiological adaptations in a time-efficient manner. This work has largely focused on the benefits of low-volume interval training, which involves a relatively small total amount of exercise, as compared with the traditional high-volume approach to training historically favored by militaries. Studies that have directly compared interval and moderate-intensity continuous training have shown similar improvements in cardiorespiratory fitness and the capacity for aerobic energy metabolism, despite large differences in total exercise and training time commitment. Interval training can also be applied in a calisthenics manner to improve cardiorespiratory fitness and strength, and this approach could easily be incorporated into a military conditioning environment. Although interval training can elicit physiological changes in men and women, the potential for sex-specific adaptations in the adaptive response to interval training warrants further investigation. Additional work is needed to clarify adaptations occurring over the longer term; however, interval training deserves consideration from a military applicability standpoint as a time-efficient training strategy to enhance soldier health and performance. There is value for military leaders in identifying strategies that reduce the time required for exercise, but nonetheless provide an effective training stimulus.

New exercise-integrated technology can monitor the dosage and quality of exercise performed against an elastic resistance band by adolescents with patellofemoral pain: an observational study.

PubMed

Rathleff, Michael S; Bandholm, Thomas; McGirr, Kate A; Harring, Stine I; Sørensen, Anders S; Thorborg, Kristian

2016-07-01

Is the exercise-integrated Bandcizer™ system feasible for recording exercise dosage (time under tension (TUT) and repetitions) and pain scores among adolescents with patellofemoral pain? Do adolescents practise the exercises as prescribed (TUT and repetitions)? Do adolescents accurately report the exercises they do in an exercise diary? Observational feasibility study. Twenty adolescents between 15 and 19 years of age with patellofemoral pain. Participants were prescribed three exercise sessions per week (one with and two without supervision) for 6 weeks. The exercises included three hip and one knee exercise with an elastic resistance band. Participants were instructed to perform three sets with a predefined TUT (3seconds concentric; 2seconds isometric; 3seconds eccentric; 2seconds pause), equating to 80seconds for 10 repetitions (one set). The exercise-integrated system consisted of a sensor attached to the elastic resistance band that was connected to the Bandtrainer app on an electronic tablet device. Pain intensity was reported on a visual analogue scale on the app. Participants also completed a self-report exercise diary. No major problems were reported with the system. Participants performed 2541 exercise sets during the 6 weeks; 5% were performed with the predefined TUT (ie, within 10seconds of the 80-second target) and 90% were performed below the target TUT. On average, the participants received 15% of the instructed exercise dosage based on TUT. The exercise dosage reported in the exercise diaries was 2.3 times higher than the TUT data from the electronic system. Pain intensity was successfully collected in 100% of the exercise sets. The system was feasible for adolescents with patellofemoral pain. The system made it possible to capture detailed data about the TUT, repetitions and sets during home-based exercises together with pain intensity before and after each exercise. [Rathleff MS, Bandholm T, McGirr KA, Harring SI, Sørensen AS, Thorborg K (2016) New exercise-integrated technology can monitor the dosage and quality of exercise performed against an elastic resistance band by adolescents with patellofemoral pain: an observational study.Journal of Physiotherapy62: 159-163]. Copyright © 2016 Australian Physiotherapy Association. Published by Elsevier B.V. All rights reserved.

Effects of treadmill exercise intensity on spatial working memory and long-term memory in rats.

PubMed

Wang, Xiao-Qin; Wang, Gong-Wu

2016-03-15

Moderate exercise promotes learning and memory. Most studies mainly focused on memory exercise effects of in the ageing and patients. There is lack of quantitative research about effect of regular exercise intensity on different memory types in normal subjects. Present study investigated the effects of different intensities of treadmill exercise on working memory and long-term memory. Fifty female Wistar rats were trained by T-maze delayed spatial alternation (DSA) task with 3 delays (10s, 60s and 300s). Then they got a 30min treadmill exercise for 30days in 4 intensities (control, 0m/min; lower, 15m/min; middle, 20m/min, and higher, 30m/min). Then animals were tested in DSA, passive avoidance and Morris water maze tasks. 1. Exercise increased the neuronal density of hippocampal subregions (CA1, CA3 and dentate gyrus) vs. naïve/control. 2. In DSA task, all groups have similar baseline, lower intensity improved 10s delay accuracy vs. baseline/control; middle and higher intensities improved 300s delay accuracy vs. baseline/control. 3. In water maze learning, all groups successfully found the platform, but middle intensity improved platform field crossing times vs. control in test phase. Present results suggested that treadmill exercise can improve long-term spatial memory and working memory; lower intensity benefits to short-term delayed working memory, and middle or higher intensity benefits to long-term delayed working memory. There was an inverted U dose-effect relationship between exercise intensity and memory performance, but exercise -working memory effect was impacted by delay duration. Copyright © 2016 Elsevier Inc. All rights reserved.

Energy-matched moderate and high intensity exercise training improves nonalcoholic fatty liver disease risk independent of changes in body mass or abdominal adiposity - A randomized trial.

PubMed

Winn, Nathan C; Liu, Ying; Rector, R Scott; Parks, Elizabeth J; Ibdah, Jamal A; Kanaley, Jill A

2018-01-01

Exercise training is commonly prescribed for individuals diagnosed with nonalcoholic fatty liver disease (NAFLD); however, consensus regarding the volume and intensity of exercise for optimal benefits is lacking. Thus, we determined whether high intensity interval exercise training (HIIT) produced greater reductions in intrahepatic lipid (IHL) content and NAFLD risk factors compared with energy-matched moderate intensity continuous exercise training (MICT) in obese adults with liver steatosis. Eighteen obese adults were randomized to either 4weeks of HIIT (4min 80% VO 2 peak/3min, 50% VO 2 peak) or MICT (55% VO 2 peak, ~60min), matched for energy expenditure (~400kcal/session) and compared to five non-exercising age-matched control subjects. IHL was measured by 1 H-MRS and frequent blood samples were analyzed for glucose, insulin, c-peptide, and NEFA levels during a liquid meal test (180min) to characterize metabolic phenotype. Baseline body weight, visceral abdominal adiposity, and fasting insulin concentrations were greater in the MICT vs HIIT group (P<0.05), while IHL was tightly matched between MICT and HIIT subjects (P>0.05), albeit higher than control subjects (P<0.01). Visceral abdominal adiposity, body mass, liver aminotransferases (ALT, AST), and hepatic apoptotic/inflammatory markers (cytokeratin 18 and fetuin a) were not reduced with either exercise training intervention (P>0.05). Both HIIT and MICT lowered IHL (HIIT, -37.0±12.4%; MICT, -20.1±6.6%, P<0.05); however, the reduction in IHL was not statistically different between exercise intensities (P=0.25). Furthermore, exercise training decreased postprandial insulin, c-peptide, and lipid peroxidation levels (iAUC, P<0.05). Collectively, these findings indicate that energy-matched high intensity and moderate intensity exercise are effective at decreasing IHL and NAFLD risk that is not contingent upon reductions in abdominal adiposity or body mass. Copyright © 2017 Elsevier Inc. All rights reserved.

Chronic β2 -adrenoceptor agonist treatment alters muscle proteome and functional adaptations induced by high intensity training in young men.

PubMed

Hostrup, Morten; Onslev, Johan; Jacobson, Glenn A; Wilson, Richard; Bangsbo, Jens

2018-01-15

While several studies have investigated the effects of exercise training in human skeletal muscle and the chronic effect of β 2 -agonist treatment in rodent muscle, their effects on muscle proteome signature with related functional measures in humans are still incompletely understood. Herein we show that daily β 2 -agonist treatment attenuates training-induced enhancements in exercise performance and maximal oxygen consumption, and alters muscle proteome signature and phenotype in trained young men. Daily β 2 -agonist treatment abolished several of the training-induced enhancements in muscle oxidative capacity and caused a repression of muscle metabolic pathways; furthermore, β 2 -agonist treatment induced a slow-to-fast twitch muscle phenotype transition. The present study indicates that chronic β 2 -agonist treatment confounds the positive effect of high intensity training on exercise performance and oxidative capacity, which is of interest for the large proportion of persons using inhaled β 2 -agonists on a daily basis, including athletes. Although the effects of training have been studied for decades, data on muscle proteome signature remodelling induced by high intensity training in relation to functional changes in humans remains incomplete. Likewise, β 2 -agonists are frequently used to counteract exercise-induced bronchoconstriction, but the effects β 2 -agonist treatment on muscle remodelling and adaptations to training are unknown. In a placebo-controlled parallel study, we randomly assigned 21 trained men to 4 weeks of high intensity training with (HIT+β 2 A) or without (HIT) daily inhalation of β 2 -agonist (terbutaline, 4 mg dose -1 ). Of 486 proteins identified by mass-spectrometry proteomics of muscle biopsies sampled before and after the intervention, 32 and 85 were changing (false discovery rate (FDR) ≤5%) with the intervention in HIT and HIT+β 2 A, respectively. Proteome signature changes were different in HIT and HIT+β 2 A (P = 0.005), wherein β 2 -agonist caused a repression of 25 proteins in HIT+β 2 A compared to HIT, and an upregulation of 7 proteins compared to HIT. β 2 -Agonist repressed or even downregulated training-induced enrichment of pathways related to oxidative phosphorylation and glycogen metabolism, but upregulated pathways related to histone trimethylation and the nucleosome. Muscle contractile phenotype changed differently in HIT and HIT+β 2 A (P ≤ 0.001), with a fast-to-slow twitch transition in HIT and a slow-to-fast twitch transition in HIT+β 2 A. β 2 -Agonist attenuated training-induced enhancements in maximal oxygen consumption (P ≤ 0.01) and exercise performance (6.1 vs. 11.6%, P ≤ 0.05) in HIT+β 2 A compared to HIT. These findings indicate that daily β 2 -agonist treatment attenuates the beneficial effects of high intensity training on exercise performance and oxidative capacity, and causes remodelling of muscle proteome signature towards a fast-twitch phenotype. © 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.

Effect of sodium bicarbonate on prolonged running performance: A randomized, double-blind, cross-over study.

PubMed

Freis, Tanja; Hecksteden, Anne; Such, Ulf; Meyer, Tim

2017-01-01

The ability to sustain intense exercise seems to be partially limited by the body's capability to counteract decreases in both intra- and extracellular pH. While the influence of an enhanced buffering capacity via sodium bicarbonate (BICA) on short-term, high-intensity exercise performance has been repeatedly investigated, studies on prolonged endurance performances are comparatively rare, especially for running. The aim of the following study was to assess the ergogenic effects of an oral BICA substitution upon exhaustive intensive endurance running performance. In a double-blind randomized cross-over study, 18 trained runners (VO2peak: 61.2 ± 6.4 ml•min-1•kg-1) performed two exhaustive graded exercise tests and two constant load tests (30 main at 95% individual anaerobic threshold (IAT) followed by 110% IAT until exhaustion) after ingestion of either sodium bicarbonate (BICA) (0.3 g/kg) or placebo (4 g NaCl) diluted in 700 ml of water. Time to exhaustion (TTE) in the constant load test was defined as the main outcome measure. Throughout each test respiratory gas exchange measurements were conducted as well as determinations of heart rate, blood gases and blood lactate concentration. TTE in the constant load test did not differ significantly between BICA and placebo conditions (BICA: 39.6 ± 5.6 min, placebo: 39.3 ± 5.6 min; p = 0.78). While pH in the placebo test dropped to a slightly acidotic value two minutes after cessation of exercise (7.34 ± 0.05) the value in the BICA trial remained within the normal range (7.41 ± 0.06) (p < 0.001). In contrast, maximum running speed (Vmax) in the exhaustive graded exercise test was significantly higher with BICA (17.4 ± 1.0 km/h) compared to placebo (17.1 ± 1.0 km/h) (p = 0.009). The numerical difference in maximum oxygen consumption (VO2peak) failed to reach statistical significance (BICA: 61.2 ± 6.4 ml•min-1•kg-1, placebo: 59.8 ± 6.4 ml•min-1•kg-1; p = 0.31). Maximum blood lactate was significantly higher with BICA compared to the corresponding placebo test (BICA: 11.1 ± 2.3 mmol/l, placebo: 8.9 ± 3.0 mmol/l; p < 0.001). At the end of exercise, an acidotic pH value was found in both exhaustive graded exercise tests (p = 0.002). BICA caused gastrointestinal side effects in 15 patients. Maximal performance was enhanced significantly after BICA administration. The ergogenic effect of BICA in the exhaustive graded exercise test can most likely be attributed to an increased anaerobic glycolysis that is reflected by an accumulation of lactate. However, TTE in prolonged high-intensity running was not improved. Even at the end of exercise no severe metabolic acidosis was found. Metabolic acidification as one of the dominant factors causing muscular fatigue should therefore be reconsidered. German Clinical Trials Register (DRKS) DRKS00011284.

Neuromuscular fatigue during high-intensity intermittent exercise in individuals with intellectual disability.

PubMed

Borji, Rihab; Sahli, Sonia; Zarrouk, Nidhal; Zghal, Firas; Rebai, Haithem

2013-12-01

This study examined neuromuscular fatigue after high-intensity intermittent exercise in 10 men with mild intellectual disability (ID) in comparison with 10 controls. Both groups performed three maximal voluntary contractions (MVC) of knee extension with 5 min in-between. The highest level achieved was selected as reference MVC. The fatiguing exercise consists of five sets with a maximal number of flexion-extension cycles at 80% of the one maximal repetition (1RM) for the right leg at 90° with 90 s rest interval between sets. The MVC was tested again after the last set. Peak force and electromyography (EMG) signals were measured during the MVC tests. Root Mean Square (RMS) and Median Frequency (MF) were calculated. Neuromuscular efficiency (NME) was calculated as the ratio of peak force to the RMS. Before exercise, individuals with ID had a lower MVC (p<0.05) and a lower RMS (p<0.05). No significant difference between groups in MF and NME. After exercise, MVC decreases significantly in both groups (p<0.001). Individuals with ID have greater force decline (p<0.001 vs. p<0.01). RMS decreased significantly (p<0.001) whereas the NME increased significantly (p<0.05) in individuals with ID, but both remained unchanged in controls. The MF decreased significantly in both groups (p<0.001). In conclusion, individuals with ID presented a lower peak force than individuals without ID. After a high-intensity intermittent exercise, individuals with ID demonstrated a greater force decline caused by neural activation failure. When rehabilitation and sport train ID individuals, they should consider this nervous system weakness. Copyright © 2013 Elsevier Ltd. All rights reserved.

Acute and chronic effects of aerobic exercise on blood pressure in resistant hypertension: study protocol for a randomized controlled trial.

PubMed

Nascimento, L S; Santos, A C; Lucena, Jms; Silva, Lgo; Almeida, Aem; Brasileiro-Santos, M S

2017-06-02

Resistant hypertension is a specific condition that affects approximately 10% of subjects with hypertension, and is characterized by persistently high blood pressure levels even using therapy of three or more antihypertensive agents or with blood pressure control using therapy with four or more antihypertensive agents. Changes in lifestyle, such as physical exercise, are indicated for controlling blood pressure. However, investigating studies about this therapy in individuals with resistant hypertension are few. This is a randomized controlled clinical trial. Forty-eight patients with resistant hypertension will be submitted to perform four short-term interventions: aerobic exercise sessions (mild-, moderate- and high-intensity) and control session, in random order and on separate days. After the short-term sessions, the patients will be randomly allocated into four groups for 8 weeks of follow-up: mild-, moderate- and high-intensity aerobic exercise, and a control group. The primary outcome is the occurrence of blood pressure reduction (office and ambulatory analysis, and acute and chronic effects). Secondary outcomes are autonomic and hemodynamic mechanisms: cardiac and vasomotor autonomic modulation, spontaneous baroreflex sensitivity, forearm blood flow and vascular resistance. The importance of exercise for hypertension has been known for decades, but little is known about the effects on patients with resistant hypertension. This study will help to understand whether different aerobic exercise intensities can induce different responses, as well as by what mechanisms adjustments in blood pressure levels may occur. ClinicalTrials.gov, ID: NCT02670681 . Registered on 28 January 2016 (first version); Brazilian Registry Platform Clinical Trials: protocol RBR-5q24zh . Registered on 24 June 2015.

Low-level laser therapy (LLLT) in human progressive-intensity running: effects on exercise performance, skeletal muscle status, and oxidative stress.

PubMed

De Marchi, Thiago; Leal Junior, Ernesto Cesar Pinto; Bortoli, Celiana; Tomazoni, Shaiane Silva; Lopes-Martins, Rodrigo Alvaro Brandão; Salvador, Mirian

2012-01-01

The aim of this work was to evaluate the effects of low-level laser therapy (LLLT) on exercise performance, oxidative stress, and muscle status in humans. A randomized double-blind placebo-controlled crossover trial was performed with 22 untrained male volunteers. LLLT (810 nm, 200 mW, 30 J in each site, 30 s of irradiation in each site) using a multi-diode cluster (with five spots - 6 J from each spot) at 12 sites of each lower limb (six in quadriceps, four in hamstrings, and two in gastrocnemius) was performed 5 min before a standardized progressive-intensity running protocol on a motor-drive treadmill until exhaustion. We analyzed exercise performance (VO(2 max), time to exhaustion, aerobic threshold and anaerobic threshold), levels of oxidative damage to lipids and proteins, the activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), and the markers of muscle damage creatine kinase (CK) and lactate dehydrogenase (LDH). Compared to placebo, active LLLT significantly increased exercise performance (VO(2 max) p = 0.01; time to exhaustion, p = 0.04) without changing the aerobic and anaerobic thresholds. LLLT also decreased post-exercise lipid (p = 0.0001) and protein (p = 0.0230) damages, as well as the activities of SOD (p = 0.0034), CK (p = 0.0001) and LDH (p = 0.0001) enzymes. LLLT application was not able to modulate CAT activity. The use of LLLT before progressive-intensity running exercise increases exercise performance, decreases exercise-induced oxidative stress and muscle damage, suggesting that the modulation of the redox system by LLLT could be related to the delay in skeletal muscle fatigue observed after the use of LLLT.

AMPK signaling in skeletal muscle during exercise: Role of reactive oxygen and nitrogen species.

PubMed

Morales-Alamo, David; Calbet, Jose A L

2016-09-01

Reactive oxygen and nitrogen species (RONS) are generated during exercise depending on intensity, duration and training status. A greater amount of RONS is released during repeated high-intensity sprint exercise and when the exercise is performed in hypoxia. By activating adenosine monophosphate-activated kinase (AMPK), RONS play a critical role in the regulation of muscle metabolism but also in the adaptive responses to exercise training. RONS may activate AMPK by direct an indirect mechanisms. Directly, RONS may activate or deactivate AMPK by modifying RONS-sensitive residues of the AMPK-α subunit. Indirectly, RONS may activate AMPK by reducing mitochondrial ATP synthesis, leading to an increased AMP:ATP ratio and subsequent Thr(172)-AMPK phosphorylation by the two main AMPK kinases: LKB1 and CaMKKβ. In presence of RONS the rate of Thr(172)-AMPK dephosphorylation is reduced. RONS may activate LKB1 through Sestrin2 and SIRT1 (NAD(+)/NADH.H(+)-dependent deacetylase). RONS may also activate CaMKKβ by direct modification of RONS sensitive motifs and, indirectly, by activating the ryanodine receptor (Ryr) to release Ca(2+). Both too high (hypoxia) and too low (ingestion of antioxidants) RONS levels may lead to Ser(485)-AMPKα1/Ser(491)-AMPKα2 phosphorylation causing inhibition of Thr(172)-AMPKα phosphorylation. Exercise training increases muscle antioxidant capacity. When the same high-intensity training is applied to arm and leg muscles, arm muscles show signs of increased oxidative stress and reduced mitochondrial biogenesis, which may be explained by differences in RONS-sensing mechanisms and basal antioxidant capacities between arm and leg muscles. Efficient adaptation to exercise training requires optimal exposure to pulses of RONS. Inappropriate training stimulus may lead to excessive RONS formation, oxidative inactivation of AMPK and reduced adaptation or even maladaptation. Theoretically, exercise programs should be designed taking into account the intrinsic properties of different skeletal muscles, the specific RONS induction and the subsequent signaling responses. Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of a Short-Term High-Nitrate Diet on Exercise Performance

PubMed Central

Porcelli, Simone; Pugliese, Lorenzo; Rejc, Enrico; Pavei, Gaspare; Bonato, Matteo; Montorsi, Michela; La Torre, Antonio; Rasica, Letizia; Marzorati, Mauro

2016-01-01

It has been reported that nitrate supplementation can improve exercise performance. Most of the studies have used either beetroot juice or sodium nitrate as a supplement; there is lack of data on the potential ergogenic benefits of an increased dietary nitrate intake from a diet based on fruits and vegetables. Our aim was to assess whether a high-nitrate diet increases nitric oxide bioavailability and to evaluate the effects of this nutritional intervention on exercise performance. Seven healthy male subjects participated in a randomized cross-over study. They were tested before and after 6 days of a high (HND) or control (CD) nitrate diet (~8.2 mmol∙day−1 or ~2.9 mmol∙day−1, respectively). Plasma nitrate and nitrite concentrations were significantly higher in HND (127 ± 64 µM and 350 ± 120 nM, respectively) compared to CD (23 ± 10 µM and 240 ± 100 nM, respectively). In HND (vs. CD) were observed: (a) a significant reduction of oxygen consumption during moderate-intensity constant work-rate cycling exercise (1.178 ± 0.141 vs. 1.269 ± 0.136 L·min−1); (b) a significantly higher total muscle work during fatiguing, intermittent sub-maximal isometric knee extension (357.3 ± 176.1 vs. 253.6 ± 149.0 Nm·s·kg−1); (c) an improved performance in Repeated Sprint Ability test. These findings suggest that a high-nitrate diet could be a feasible and effective strategy to improve exercise performance. PMID:27589795

Exercise-induced oxidative stress and hypoxic exercise recovery.

PubMed

Ballmann, Christopher; McGinnis, Graham; Peters, Bridget; Slivka, Dustin; Cuddy, John; Hailes, Walter; Dumke, Charles; Ruby, Brent; Quindry, John

2014-04-01

Hypoxia due to altitude diminishes performance and alters exercise oxidative stress responses. While oxidative stress and exercise are well studied, the independent impact of hypoxia on exercise recovery remains unknown. Accordingly, we investigated hypoxic recovery effects on post-exercise oxidative stress. Physically active males (n = 12) performed normoxic cycle ergometer exercise consisting of ten high:low intensity intervals, 20 min at moderate intensity, and 6 h recovery at 975 m (normoxic) or simulated 5,000 m (hypoxic chamber) in a randomized counter-balanced cross-over design. Oxygen saturation was monitored via finger pulse oximetry. Blood plasma obtained pre- (Pre), post- (Post), 2 h post- (2Hr), 4 h post- (4Hr), and 6 h (6Hr) post-exercise was assayed for Ferric Reducing Ability of Plasma (FRAP), Trolox Equivalent Antioxidant Capacity (TEAC), Lipid Hydroperoxides (LOOH), and Protein Carbonyls (PC). Biopsies from the vastus lateralis obtained Pre and 6Hr were analyzed by real-time PCR quantify expression of Heme oxygenase 1 (HMOX1), Superoxide Dismutase 2 (SOD2), and Nuclear factor (euthyroid-derived2)-like factor (NFE2L2). PCs were not altered between trials, but a time effect (13 % Post-2Hr increase, p = 0.044) indicated exercise-induced blood oxidative stress. Plasma LOOH revealed only a time effect (p = 0.041), including a 120 % Post-4Hr increase. TEAC values were elevated in normoxic recovery versus hypoxic recovery. FRAP values were higher 6Hr (p = 0.045) in normoxic versus hypoxic recovery. Exercise elevated gene expression of NFE2L2 (20 % increase, p = 0.001) and SOD2 (42 % increase, p = 0.003), but hypoxic recovery abolished this response. Data indicate that recovery in a hypoxic environment, independent of exercise, may alter exercise adaptations to oxidative stress and metabolism.

Exercise intensity modulates the change in cerebral blood flow following aerobic exercise in chronic stroke.

PubMed

Robertson, Andrew D; Crane, David E; Rajab, A Saeed; Swardfager, Walter; Marzolini, Susan; Shirzadi, Zahra; Middleton, Laura E; MacIntosh, Bradley J

2015-08-01

The mechanisms supporting functional improvement by aerobic exercise following stroke remain incompletely understood. This study investigated how cycling intensity and aerobic fitness influence cerebral blood flow (CBF) following a single exercise session. Thirteen community-living stroke survivors performed 20 min of semi-recumbent cycling at low and moderate intensities (40-50 and 60-70 % of heart rate reserve, respectively) as determined from an exercise stress test. CBF was quantified by arterial spin labeling MRI at baseline, as well as 30 and 50 min post-exercise. An intensity-dependent effect was observed in the right post-central and supramarginal gyri up to 50 min after exercise (uncorrected p < 0.005, cluster size ≥10). Regional CBF was increased 18 ± 17 % and reduced 8 ± 12 % following moderate- and low-intensity cycling, respectively. In contrast, CBF changes were similar between sessions in the right lentiform nucleus and mid-frontal gyrus, as well as the left temporal and parietal gyri. Aerobic fitness was directly related to posterior cingulate and thalamic CBF, and inversely related to precuneal CBF at rest (R (2) ≥ 0.75); however, no relationship between fitness and the post-exercise change in CBF was observed. Divergent changes in regional CBF were observed in the right parietal cortex following low- and moderate-intensity exercise, which suggests that intensity of prescribed exercise may be useful in optimizing rehabilitation.

Influences of two high intensity interval exercise protocols on the main determinants of blood fluidity in overweight men.

PubMed

Ahmadizad, Sajad; Bassami, Minoo; Hadian, Mohsen; Eslami, Maryam

2016-01-01

Acute effects of continuous exercise on the markers of blood fluidity have been addressed in different populations and the changes are intensity related. However, the effect of different high intensity interval exercise (HIIE) on these variables is unclear. This study is designed to determine the effects of two different HIIE with different work/rest ratios but the same energy expenditure on the main determinants of blood fluidity. Ten overweight men (age, 26.3±1.7 yrs) completed two HIIE protocols on two separate occasions with one week intervening. The two HIIE encompassed performing: 1) 6 intervals of 2 min activity at 85% of VO2max interspersed by 2 min active recovery at 30% of VO2max (ratio 1 to 1, HIIE1/1), and 2) 6 intervals of 30 s activity at 110% of VO2max interspersed by 4 min active recovery at 40% of VO2max (ratio 1 to 8, HIIE1/8). Each exercise trial was followed by 30 min rest. Venous blood samples were obtained before exercise, immediately after exercise and after recovery and analyzed for blood and plasma viscosity, fibrinogen and red blood cell indices. The HIIE1/1 protocol led to higher reduction (P < 0.01) in plasma volume changes compared to HIIE1/8 (9.9% vs 5.7%). Moreover, increases in blood viscosity, plasma viscosity, hematocrit, RBC count and mean arterial blood pressure observed following HIIE1/1 were significantly (P < 0.05) higher than HIIE1/8 ; whereas, the changes in fibrinogen concentration neither were significant in response to both trials nor were significantly different between two protocols (P > 0.05). However, the changes in all variables during exercise were transient and returned to the baseline levels after 30 min recovery. It is concluded that the HIIE protocol with lower intensity and shorter rest intervals (higher work to rest ratio) clearly results in more physiological strain than HIIE with higher intensity but longer rest intervals (lower work to rest ratio) in overweight individuals, and that the work to rest ratio could be as important as exercise intensity when considering the hemorheological variables during HIIE.

Early Exercise in the Burn Intensive Care Unit Decreases Hospital Stay, Improves Mental Health, and Physical Performance

DTIC Science & Technology

2017-10-01

Decreases Hospital Stay, Improves Mental Health , and Physical Performance 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Oscar E. Suman, PhD...Multicenter Study of the Effect of In-Patient Exercise Training on Length of Hospitalization, Mental Health , and Physical Performance in Burned...Intensive Care Unit Decreases Hospital Stay, Improves Mental Health , and Physical Performance,” Proposal Log Number 13214039, Award Number W81XWH-14

Irisin in response to exercise in humans with and without metabolic syndrome.

PubMed

Huh, Joo Young; Siopi, Aikaterina; Mougios, Vassilis; Park, Kyung Hee; Mantzoros, Christos S

2015-03-01

Irisin is a recently identified exercise-induced myokine. However, the circulating levels of irisin in response to different types of exercise in subjects with metabolic syndrome are unknown. This study aimed to study the levels of irisin in healthy males and subjects with metabolic syndrome at baseline and in response to exercise. Each individual completed high-intensity interval exercise (HIIE), continuous moderate-intensity exercise (CME), and resistance exercise (RE) sessions in a random, crossover design. Percentage change in circulating irisin levels was examined. Two different irisin assays were used to compare the results of the RE study. Circulating irisin increased immediately after HIIE, CME, and RE and declined 1 hour later. The increase was greater in response to resistance compared with either high-intensity intermittent exercise or CME. Change in irisin in response to exercise did not differ between individuals with and without metabolic syndrome. Exercise is able to increase circulating irisin levels in individuals with the metabolic syndrome as well as healthy individuals. Whether this increase may contribute to the beneficial effects of exercise on patients with the metabolic syndrome remains to be studied further.

The Effect of Music on Exercise Intensity among Children with Autism Spectrum Disorder: A Pilot Study

PubMed Central

Woodman, Ashley C.; Breviglia, Emily; Mori, Yumiko; Golden, Rebecca; Maina, John; Wisniewski, Hannah

2018-01-01

Children with autism spectrum disorder (ASD) are at risk for obesity, commonly have sleep disorders, and exhibit stereotypic behaviors that disrupt their learning. Vigorous levels of exercise have been shown to ameliorate these issues in children with ASD, but little research exists to provide techniques for motivating children with ASD to engage in exercise. The present study examined the effect of music on exercise intensity in a group of 13 elementary school students with ASD. Data were collected across six days during structured (e.g., verbal and physical prompts) and unstructured (e.g., minimal prompting) exercise periods. During these exercise periods, three music conditions were randomized: no music, slow-tempo music, and fast-tempo music. Exercise intensity, measured in Metabolic Equivalent of Tasks by triaxial accelerometers, was greatest during the structured exercise periods and during the slow music condition. Student characteristics moderated the impact of music condition on exercise intensity, such that students with high levels of adaptive behavior or lower levels of maladaptive behavior displayed greater exercise intensity during the fast music condition. PMID:29495354

My gut feeling says rest: Increased intestinal permeability contributes to chronic diseases in high-intensity exercisers.

PubMed

Van Houten, Jason M; Wessells, Robert J; Lujan, Heidi L; DiCarlo, Stephen E

2015-12-01

Chronic diseases are the leading cause of death and disability worldwide, and many of these conditions are linked to chronic inflammation. One potential cause of chronic inflammation is an increased intestinal epithelial permeability. Recent studies have demonstrated that parasympathetic stimulation via the efferent abdominal vagus nerve increases the expression and proper localization of tight junction proteins and decreases intestinal epithelial permeability. This finding may provide a novel approach for treating and preventing many chronic conditions. Importantly, physical activity is associated with increased resting parasympathetic (vagal) activity and lower risk of chronic diseases. However, high intensity long duration exercise can be harmful to overall health. Specifically, individuals who frequently exercise strenuously and for longer time intervals have the same mortality rates as sedentary individuals. This may be explained, in part, by longer periods of reduced vagal activity as vagal activity is markedly reduced both during and after intense exercise. We hypothesize that one mechanism by which exercise provides its health benefits is by increasing resting vagal activity and decreasing intestinal epithelial permeability, thus decreasing chronic inflammation. Additionally, we hypothesize that long periods of reduced vagal activity in individuals who exercise at high intensities and for longer durations, decrease the integrity of the intestinal barrier, putting them at greater risk of chronic inflammation and a host of chronic diseases. Thus, this hypothesis provides a conceptual link between the well-established benefits of frequent exercise and the paradoxical deleterious effects of prolonged, high-intensity exercise without adequate rest. Copyright © 2015. Published by Elsevier Ltd.

Acute low-intensity cycling with blood-flow restriction has no effect on metabolic signaling in human skeletal muscle compared to traditional exercise.

PubMed

Smiles, William J; Conceição, Miguel S; Telles, Guilherme D; Chacon-Mikahil, Mara P T; Cavaglieri, Cláudia R; Vechin, Felipe C; Libardi, Cleiton A; Hawley, John A; Camera, Donny M

2017-02-01

Autophagy is an intracellular degradative system sensitive to hypoxia and exercise-induced perturbations to cellular bioenergetics. We determined the effects of low-intensity endurance-based exercise performed with blood-flow restriction (BFR) on cell signaling adaptive responses regulating autophagy and substrate metabolism in human skeletal muscle. In a randomized cross-over design, nine young, healthy but physically inactive males completed three experimental trials separated by 1 week of recovery consisting of either a resistance exercise bout (REX: 4 × 10 leg press repetitions, 70% 1-RM), endurance exercise (END: 30 min cycling, 70% VO 2peak ), or low-intensity cycling with BFR (15 min, 40% VO 2peak ). A resting muscle biopsy was obtained from the vastus lateralis 2 weeks prior to the first exercise trial and 3 h after each exercise bout. END increased ULK1 Ser757 phosphorylation above rest and BFR (~37 to 51%, P < 0.05). Following REX, there were significant elevations compared to rest (~348%) and BFR (~973%) for p38γ MAPK Thr180/Tyr182 phosphorylation (P < 0.05). Parkin content was lower following BFR cycling compared to REX (~20%, P < 0.05). There were no exercise-induced changes in select markers of autophagy following BFR. Genes implicated in substrate metabolism (HK2 and PDK4) were increased above rest (~143 to 338%) and BFR cycling (~212 to 517%) with END (P < 0.001). A single bout of low-intensity cycling with BFR is insufficient to induce intracellular "stress" responses (e.g., high rates of substrate turnover and local hypoxia) necessary to activate skeletal muscle autophagy signaling.

Blood pressure and calf muscle oxygen extraction during plantar flexion exercise in peripheral artery disease.

PubMed

Luck, J Carter; Miller, Amanda J; Aziz, Faisal; Radtka, John F; Proctor, David N; Leuenberger, Urs A; Sinoway, Lawrence I; Muller, Matthew D

2017-07-01

Peripheral artery disease (PAD) is an atherosclerotic vascular disease that affects 200 million people worldwide. Although PAD primarily affects large arteries, it is also associated with microvascular dysfunction, an exaggerated blood pressure (BP) response to exercise, and high cardiovascular mortality. We hypothesized that fatiguing plantar flexion exercise that evokes claudication elicits a greater reduction in skeletal muscle oxygenation (SmO 2 ) and a higher rise in BP in PAD compared with age-matched healthy subjects, but low-intensity steady-state plantar flexion elicits similar responses between groups. In the first experiment, eight patients with PAD and eight healthy controls performed fatiguing plantar flexion exercise (from 0.5 to 7 kg for up to 14 min). In the second experiment, seven patients with PAD and seven healthy controls performed low-intensity plantar flexion exercise (2.0 kg for 14 min). BP, heart rate (HR), and SmO 2 were measured continuously using near-infrared spectroscopy (NIRS). SmO 2 is the ratio of oxygenated hemoglobin to total hemoglobin, expressed as a percent. At fatigue, patients with PAD had a greater increase in mean arterial BP (18 ± 2 vs. vs. 10 ± 2 mmHg, P = 0.029) and HR (14 ± 2 vs. 6 ± 2 beats/min, P = 0.033) and a greater reduction in SmO 2 (-54 ± 10 vs. -12 ± 4%, P = 0.001). However, both groups had similar physiological responses to low-intensity, nonpainful plantar flexion exercise. These data suggest that patients with PAD have altered oxygen uptake and/or utilization during fatiguing exercise coincident with an augmented BP response. NEW & NOTEWORTHY In this laboratory study, patients with peripheral artery disease performed plantar flexion exercise in the supine posture until symptoms of claudication occurred. Relative to age- and sex-matched healthy subjects we found that patients had a higher blood pressure response, a higher heart rate response, and a greater reduction in skeletal muscle oxygenation as determined by near-infrared spectroscopy. Our data suggest that muscle ischemia contributes to the augmented exercise pressor reflex in peripheral artery disease. Copyright © 2017 the American Physiological Society.

A single exercise bout and locomotor learning after stroke: physiological, behavioural, and computational outcomes.

PubMed

Charalambous, Charalambos C; Alcantara, Carolina C; French, Margaret A; Li, Xin; Matt, Kathleen S; Kim, Hyosub E; Morton, Susanne M; Reisman, Darcy S

2018-05-15

Previous work demonstrated an effect of a single high-intensity exercise bout coupled with motor practice on the retention of a newly acquired skilled arm movement, in both neurologically intact and impaired adults. In the present study, using behavioural and computational analyses we demonstrated that a single exercise bout, regardless of its intensity and timing, did not increase the retention of a novel locomotor task after stroke. Considering both present and previous work, we postulate that the benefits of exercise effect may depend on the type of motor learning (e.g. skill learning, sensorimotor adaptation) and/or task (e.g. arm accuracy-tracking task, walking). Acute high-intensity exercise coupled with motor practice improves the retention of motor learning in neurologically intact adults. However, whether exercise could improve the retention of locomotor learning after stroke is still unknown. Here, we investigated the effect of exercise intensity and timing on the retention of a novel locomotor learning task (i.e. split-belt treadmill walking) after stroke. Thirty-seven people post stroke participated in two sessions, 24 h apart, and were allocated to active control (CON), treadmill walking (TMW), or total body exercise on a cycle ergometer (TBE). In session 1, all groups exercised for a short bout (∼5 min) at low (CON) or high (TMW and TBE) intensity and before (CON and TMW) or after (TBE) the locomotor learning task. In both sessions, the locomotor learning task was to walk on a split-belt treadmill in a 2:1 speed ratio (100% and 50% fast-comfortable walking speed) for 15 min. To test the effect of exercise on 24 h retention, we applied behavioural and computational analyses. Behavioural data showed that neither high-intensity group showed greater 24 h retention compared to CON, and computational data showed that 24 h retention was attributable to a slow learning process for sensorimotor adaptation. Our findings demonstrated that acute exercise coupled with a locomotor adaptation task, regardless of its intensity and timing, does not improve retention of the novel locomotor task after stroke. We postulate that exercise effects on motor learning may be context specific (e.g. type of motor learning and/or task) and interact with the presence of genetic variant (BDNF Val66Met). © 2018 The Authors. The Journal of Physiology © 2018 The Physiological Society.

The Effects of Fructose and Glucose on High Intensity Endurance Performance.

ERIC Educational Resources Information Center

McMurray, Robert G.; And Others

1983-01-01

To evaluate the effects of drinking glucose and fructose before prolonged exercise, six female runners were given glucose, fructose, saccharin, or plain water to drink before running to exhaustion. Metabolic processes were monitored. The best performance came from those drinking water alone. Fructose seemed preferable to glucose, however.…

A pilot study on quantification of training load: The use of HRV in training practice.

PubMed

Saboul, Damien; Balducci, Pascal; Millet, Grégoire; Pialoux, Vincent; Hautier, Christophe

2016-01-01

Recent laboratory studies have suggested that heart rate variability (HRV) may be an appropriate criterion for training load (TL) quantification. The aim of this study was to validate a novel HRV index that may be used to assess TL in field conditions. Eleven well-trained long-distance male runners performed four exercises of different duration and intensity. TL was evaluated using Foster and Banister methods. In addition, HRV measurements were performed 5 minutes before exercise and 5 and 30 minutes after exercise. We calculated HRV index (TLHRV) based on the ratio between HRV decrease during exercise and HRV increase during recovery. HRV decrease during exercise was strongly correlated with exercise intensity (R = -0.70; p < 0.01) but not with exercise duration or training volume. TLHRV index was correlated with Foster (R = 0.61; p = 0.01) and Banister (R = 0.57; p = 0.01) methods. This study confirms that HRV changes during exercise and recovery phase are affected by both intensity and physiological impact of the exercise. Since the TLHRV formula takes into account the disturbance and the return to homeostatic balance induced by exercise, this new method provides an objective and rational TL index. However, some simplification of the protocol measurement could be envisaged for field use.

Effect of incorporating low intensity exercise into the recovery period after a rugby match.

PubMed

Suzuki, M; Umeda, T; Nakaji, S; Shimoyama, T; Mashiko, T; Sugawara, K

2004-08-01

The psychological and physiological condition of athletes affect both their performance in competitions and their health. Rugby is an intense sport which appears to impose psychological and physiological stress on players. However, there have been few studies of the most appropriate resting techniques to deliver effective recovery from a match. To compare the difference in recovery after a match using resting techniques with or without exercise. Fifteen Japanese college rugby football players were studied. Seven performed only normal daily activities and eight performed additional low intensity exercise during the post-match rest period. Players were examined just before and immediately after the match and one and two days after the match. Blood biochemistry and two neutrophil functions, phagocytic activity and oxidative burst, were measured to assess physiological condition, and the profile of mood states (POMS) scores were examined to evaluate psychological condition. Immediately after the match, muscle damage, decreases in neutrophil functions, and mental fatigue were observed in both groups. Muscle damage and neutrophil functions recovered with time almost equally in the two groups, but the POMS scores were significantly decreased only in subjects in the low intensity exercise group. Rugby matches impose both physiological and psychological stress on players. The addition of low intensity exercise to the rest period did not adversely affect physiological recovery and had a significantly beneficial effect on psychological recovery by enhancing relaxation.

The effect of histamine on changes in mental energy and fatigue after a single bout of exercise.

PubMed

Loy, Bryan D; O'Connor, Patrick J

2016-01-01

The purpose of this research was to determine if histamine, acting on brain H1 receptors, influences changes in feelings of energy and fatigue or cognitive test performance after acute exercise. Women (n=20) with low vigor and high fatigue were administered the H1 antagonist drug doxepin hydrocholoride (6 mg) in tomato juice and tomato juice alone (placebo) in a randomized, double-blinded, cross-over experiment before performing 30 min of light intensity cycling exercise and completing energy, fatigue, sleepiness, and motivation scales, and cognitive tasks. After exercise, mental fatigue increased for the doxepin condition (p=0.014) but not placebo (p=0.700), while mental energy decreased for both PLA and DOX (p<0.001) and cognitive task performance was unaffected. It is inferred that histamine binding to H1 receptors in the brain has a role in exercise-induced reductions in mental fatigue, but not increases in energy. Copyright © 2015 Elsevier Inc. All rights reserved.

Changes in technique and efficiency after high-intensity exercise in cross-country skiers.

PubMed

Åsan Grasaas, Christina; Ettema, Gertjan; Hegge, Ann Magdalen; Skovereng, Knut; Sandbakk, Øyvind

2014-01-01

This study investigated changes in technique and efficiency after high-intensity exercise to exhaustion in elite cross-country skiers. Twelve elite male skiers completed 4 min submaximal exercise before and after a high-intensity incremental test to exhaustion with the G3 skating technique on a 5% inclined roller-ski treadmill. Kinematics and kinetics were monitored by instrumented roller skis, work rate was calculated as power against roller friction and gravity, aerobic metabolic cost was determined from gas exchange, and blood lactate values indicated the anaerobic contribution. Gross efficiency was the work rate divided by aerobic metabolic rate. A recovery period of 10 min between the incremental test and the posttest was included to allow the metabolic values to return to baseline. Changes in neuromuscular fatigue in upper and lower limbs before and after the incremental test were indicated by peak power in concentric bench press and squat-jump height. From pretest to posttest, cycle length decreased and cycle rate increased by approximately 5% (P < 0.001), whereas the amount of ski forces did not change significantly. Oxygen uptake increased by 4%, and gross efficiency decreased from 15.5% ± 0.7% to 15.2% ± 0.5% from pretest to posttest (both P < .02). Correspondingly, blood lactate concentration increased from 2.4 ± 1.0 to 6.2 ± 2.5 mmol/L (P < .001). Bench-press and squat-jump performance remained unaltered. Elite cross-country skiers demonstrated a less efficient technique and shorter cycle length during submaximal roller-ski skating after high-intensity exercise. However, there were no changes in ski forces or peak power in the upper and lower limbs that could explain these differences.

The Effects of Acute Physical Exercise on Memory, Peripheral BDNF, and Cortisol in Young Adults

PubMed Central

Röder, Brigitte; Schmidt-Kassow, Maren

2016-01-01

In animals, physical activity has been shown to induce functional and structural changes especially in the hippocampus and to improve memory, probably by upregulating the release of neurotrophic factors. In humans, results on the effect of acute exercise on memory are inconsistent so far. Therefore, the aim of the present study was to assess the effects of a single bout of physical exercise on memory consolidation and the underlying neuroendocrinological mechanisms in young adults. Participants encoded a list of German-Polish vocabulary before exercising for 30 minutes with either high intensity or low intensity or before a relaxing phase. Retention of the vocabulary was assessed 20 minutes after the intervention as well as 24 hours later. Serum BDNF and salivary cortisol were measured at baseline, after learning, and after the intervention. The high-intensity exercise group showed an increase in BDNF and cortisol after exercising compared to baseline. Exercise after learning did not enhance the absolute number of recalled words. Participants of the high-intensity exercise group, however, forgot less vocabulary than the relaxing group 24 hours after learning. There was no robust relationship between memory scores and the increase in BDNF and cortisol, respectively, suggesting that further parameters have to be taken into account to explain the effects of exercise on memory in humans. PMID:27437149

Does a single session of high-intensity interval training provoke a transient elevated risk of falling in seniors and adults?

PubMed

Donath, Lars; Kurz, Eduard; Roth, Ralf; Hanssen, Henner; Schmidt-Trucksäss, Arno; Zahner, Lukas; Faude, Oliver

2015-01-01

Balance and strength training can reduce seniors' fall risk up to 50%. Available evidence suggests that acute bouts of neuromuscular and endurance exercise deteriorate postural control. High-intensity endurance training has been successfully applied in different populations. Thus, it seemed valuable to examine the acute effects of high-intensity interval training (HIIT) on neuromuscular performance in seniors and young adults. The acute impact of a HIIT session on balance performance and muscle activity after exercise cessation and during post-exercise recovery was examined in young and old adults. We intended to investigate whether a transient exercise-induced fall-risk may occur in both groups. 20 healthy seniors (age 70 (SD 4) years) and young adults (age 27 (SD 3) years) were examined on 3 days. After exhaustive ramp-like treadmill testing in order to determine maximal heart rate (HRmax) on the first day, either a 4 × 4 min HIIT at 90% of HRmax or a control condition (CON) was randomly performed on the second and third day, respectively. Balance performance (postural sway) was assessed during single limb stance with open eyes (SLEO) and double limb stance with closed eyes (DLEC). EMG was recorded for the soleus (SOL), anterior tibialis (TIB), gastrocnemius (GM) and peroneus longus (PL) muscles at the dominant leg. All measures were collected before, immediately as well as 10, 30 and 45 min after HIIT and CON, respectively. Compared to CON, HIIT induced significant increases of postural sway immediately after exercise cessation during SLEO in both groups (adults: p < 0.001, Δ = +25% sway; seniors: p = 0.007, Δ = +15% sway). Increased sway during DLEC was only found for seniors immediately and 10 min after HIIT (post: p = 0.003, Δ = +14% sway, 10 min post: p = 0.004, Δ = +18% sway). Muscle activity was increased during SLEO for TIB until 10 min post in seniors (0.008 < p < 0.03) and immediately after HIIT in adults (p < 0.001). HIIT training may cause an acute 'open-fall-window' with a transient impairment of balance performance for at least 10 min after exercise cessation in both groups. Occluded vision in seniors seems to prolong this period up to 30 min. Thus, the advantage of HIIT with regard to time efficiency seems debatable when considering transient HIIT-induced impairments of neuromuscular function. © 2014 S. Karger AG, Basel.

Low-intensity aerobic exercise training: inhibition of skeletal muscle atrophy in high-fat-diet-induced ovariectomized rats.

PubMed

Kim, Hye Jin; Lee, Won Jun

2017-09-30

Postmenopausal women are highly susceptible to diseases, such as obesity, type 2 diabetes, osteoporosis, or skeletal muscle atrophy and many people recognize the need for regular physical activity. Aerobic exercise training is known to improve the oxidative capacity and insulin sensitivity of skeletal muscles. This study aimed to investigate the role of low-intensity aerobic exercise training on skeletal muscle protein degradation or synthesis in the plantaris muscles of high-fat-fed ovariectomized rats. Ovariectomized female rats were divided into two groups: a high-fat diet-sedentary group (HFD), and a high-fat diet-aerobic exercise group (HFD+EX). The exercise group exercised aerobically on a treadmill 5 days/week for 8 weeks. The rats progressively ran 30 min/day at 15 m/min, up to 40 min/day at 18 m/min, 0% slope, in the last 4 weeks. Although aerobic exercise led to significantly increased AMP-activated protein kinase (AMPK) phosphorylation at Thr172, phosphorylation of the mammalian target of rapamycin (mTOR) substrate Thr389 S6K1 level did not decrease. Additionally, even though Akt activity did not increase at Ser473, the atrogin-1 level significantly decreased in the exercise group compared to the non-exercise group. Immunohistochemical staining revealed that high-fat-induced TSC2 protein expression was eliminated in response to aerobic exercise. These results suggest that aerobic exercise can inhibit skeletal muscle protein degradation, but it cannot increase protein synthesis in the plantaris muscle of high-fat-fed ovariectomized rats. Our findings have implications in understanding skeletal muscle mass maintenance with low intensity aerobic exercise in post-menopausal women. ©2017 The Korean Society for Exercise Nutrition

Closed-Loop Insulin Delivery for Adults with Type 1 Diabetes Undertaking High-Intensity Interval Exercise Versus Moderate-Intensity Exercise: A Randomized, Crossover Study.

PubMed

Jayawardene, Dilshani C; McAuley, Sybil A; Horsburgh, Jodie C; Gerche, André La; Jenkins, Alicia J; Ward, Glenn M; MacIsaac, Richard J; Roberts, Timothy J; Grosman, Benyamin; Kurtz, Natalie; Roy, Anirban; O'Neal, David N

2017-06-01

We aimed to compare closed-loop glucose control for people with type 1 diabetes undertaking high-intensity interval exercise (HIIE) versus moderate-intensity exercise (MIE). Adults with type 1 diabetes established on insulin pumps undertook HIIE and MIE stages in random order during automated insulin delivery via a closed-loop system (Medtronic). Frequent venous sampling for glucose, lactate, ketones, insulin, catecholamines, cortisol, growth hormone, and glucagon levels was performed. The primary outcome was plasma glucose <4.0 mmol/L for ≥15 min, from exercise commencement to 120 min postexercise. Secondary outcomes included continuous glucose monitoring and biochemical parameters. Twelve adults (age mean ± standard deviation 40 ± 13 years) were recruited; all completed the study. Plasma glucose of one participant fell to 3.4 mmol/L following MIE completion; no glucose levels were <4.0 mmol/L for HIIE (primary outcome). There were no glucose excursions >15.0 mmol/L for either stage. Mean (±standard error) plasma glucose did not differ between stages pre-exercise; was higher during exercise in HIIE than MIE (11.3 ± 0.5 mmol/L vs. 9.7 ± 0.6 mmol/L, respectively; P < 0.001); and remained higher until 60 min postexercise. There were no differences in circulating free insulin before, during, or postexercise. During HIIE compared with MIE, there were greater increases in lactate (P < 0.001), catecholamines (all P < 0.05), and cortisol (P < 0.001). Ketones increased more with HIIE than MIE postexercise (P = 0.031). Preliminary findings suggest that closed-loop glucose control is safe for people undertaking HIIE and MIE. However, the management of the postexercise rise in ketones secondary to counter-regulatory hormone-induced insulin resistance observed with HIIE may represent a challenge for closed-loop systems.

The development of peripheral fatigue and short-term recovery during self-paced high-intensity exercise

PubMed Central

Froyd, Christian; Millet, Guillaume Y; Noakes, Timothy D

2013-01-01

The time course of muscular fatigue that develops during and after an intense bout of self-paced dynamic exercise was characterized by using different forms of electrical stimulation (ES) of the exercising muscles. Ten active subjects performed a time trial (TT) involving repetitive concentric extension/flexion of the right knee using a Biodex dynamometer. Neuromuscular function (NMF), including ES and a 5 s maximal isometric voluntary contraction (MVC), was assessed before the start of the TT and immediately (<5 s) after each 20% of the TT had been completed, as well as 1, 2, 4 and 8 min after TT termination. The TT time was 347 ± 98 s. MVCs were 52% of baseline values at TT termination. Torque responses from ES were reduced to 33–68% of baseline using different methods of stimulation, suggesting that the extent to which peripheral fatigue is documented during exercise depends upon NMF assessment methodology. The major changes in muscle function occurred within the first 40% of exercise. Significant recovery in skeletal muscle function occurs within the first 1–2 min after exercise, showing that previous studies may have underestimated the extent to which peripheral fatigue develops during exercise. PMID:23230235

Benefits of different intensity of aerobic exercise in modulating body composition among obese young adults: a pilot randomized controlled trial.

PubMed

Chiu, Chih-Hui; Ko, Ming-Chen; Wu, Long-Shan; Yeh, Ding-Peng; Kan, Nai-Wen; Lee, Po-Fu; Hsieh, Jenn-Woei; Tseng, Ching-Yu; Ho, Chien-Chang

2017-08-24

The aim of present study was to compare the effects of different aerobic exercise intensities and energy expenditures on the body composition of sedentary obese college students in Taiwan. Forty-eight obese participants [body mass index (BMI) ≥ 27 kg/m 2 , age 18-26 years] were randomized into four equal groups (n = 12): light-intensity training group (LITG), 40%-50% heart rate reserve (HRR); middle-intensity training group (MITG), 50%-70% HRR; high-intensity training group (HITG), 70%-80% HRR; and control group (CG). The aerobic exercise training program was conducted for 60 min per day on a treadmill 3 days per week for 12 weeks. All participant anthropometric data, blood biochemical parameters, and health-related physical fitness components were measured at baseline and after 12 weeks. At baseline, the anthropometric indices did not differ significantly among the four groups (p > 0.05). After 12-week exercise intervention, the HITG and MITG had significantly more changes in body weight, waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR) than the LITG. The changes in BMI and body fat percentage differed among all four groups (p < 0.05). A 12-week high-intensity exercise intervention with high energy expenditure can considerably reduce body weight, body fat, WC, WHR, and WHtR, whereas a light-intensity exercise intervention can significantly reduce body weight and body fat. Current Controlled Trials TPECTR09831410900 , registered on 24 th Dec 2009.

Kinetic quantification of plyometric exercise intensity.

PubMed

Ebben, William P; Fauth, McKenzie L; Garceau, Luke R; Petushek, Erich J

2011-12-01

Ebben, WP, Fauth, ML, Garceau, LR, and Petushek, EJ. Kinetic quantification of plyometric exercise intensity. J Strength Cond Res 25(12): 3288-3298, 2011-Quantification of plyometric exercise intensity is necessary to understand the characteristics of these exercises and the proper progression of this mode of exercise. The purpose of this study was to assess the kinetic characteristics of a variety of plyometric exercises. This study also sought to assess gender differences in these variables. Twenty-six men and 23 women with previous experience in performing plyometric training served as subjects. The subjects performed a variety of plyometric exercises including line hops, 15.24-cm cone hops, squat jumps, tuck jumps, countermovement jumps (CMJs), loaded CMJs equal to 30% of 1 repetition maximum squat, depth jumps normalized to the subject's jump height (JH), and single leg jumps. All plyometric exercises were assessed with a force platform. Outcome variables associated with the takeoff, airborne, and landing phase of each plyometric exercise were evaluated. These variables included the peak vertical ground reaction force (GRF) during takeoff, the time to takeoff, flight time, JH, peak power, landing rate of force development, and peak vertical GRF during landing. A 2-way mixed analysis of variance with repeated measures for plyometric exercise type demonstrated main effects for exercise type and all outcome variables (p ≤ 0.05) and for the interaction between gender and peak vertical GRF during takeoff (p ≤ 0.05). Bonferroni-adjusted pairwise comparisons identified a number of differences between the plyometric exercises for the outcome variables assessed (p ≤ 0.05). These findings can be used to guide the progression of plyometric training by incorporating exercises of increasing intensity over the course of a program.

Respiratory muscle endurance, oxygen saturation index in vastus lateralis and performance during heavy exercise.

PubMed

Oueslati, Ferid; Boone, Jan; Ahmaidi, Said

2016-06-15

The purpose of this study was to investigate the relationships between respiratory muscle endurance, tissue oxygen saturation index dynamics of leg muscle (TSI) and the time to exhaustion (TTE) during high intensity exercise. Eleven males performed a respiratory muscle endurance test, a maximal incremental running field test (8 km h(-1)+0.5 km h(-1) each 60s) and a high-intensity constant speed field test at 90% VO2max. The TSI in vastus lateralis was monitored with near-infrared spectroscopy. The TSI remained steady between 20 and 80% of TTE. Between 80 and 100% of TTE (7.5 ± 6.1%, p<0.05), a significant drop in TSI concomitant with a minute ventilation increase (16 ± 10 l min(-1)) was observed. Moreover, the increase of ventilation was correlated to the drop in TSI (r=0.70, p<0.05). Additionally, respiratory muscle endurance was significantly correlated to TSI time plateau (20-80% TTE) (r=0.83, p<0.05) and to TTE (r=0.95, p<0.001). The results of the present study show that the tissue oxygen saturation plateau might be affected by ventilatory work and that respiratory muscle endurance could be considered as a determinant of performance during heavy exercise. Copyright © 2016 Elsevier B.V. All rights reserved.

High intensity interval exercise training in overweight young women.

PubMed

Sijie, T; Hainai, Y; Fengying, Y; Jianxiong, W

2012-06-01

The purpose of this study was intended to evaluate the effects of a high intensity interval training (HIIT) program on the body composition, cardiac function and aerobic capacity in overweight young women. Sixty female university students (aged 19-20, BMI≥25kg/m2 and percentage body fat ≥ 30%) were chosen and then randomly assigned to each of the HIIT group, the moderate intensity continuous training (MICT) group and the non-training control group. The subjects in both the HIIT and MICT groups underwent exercise training five times per week for 12 weeks. In each of the training sessions, the HIIT group performed interval exercises at the individualized heart rate (HR) of 85% of VO2max and separated by brief periods of low intensity activity (HR at 50% of VO2max), while the MICT group did continuous walking and/or jogging at the individualized HR of 50% of VO2max. Both of these exercise training programs produced significant improvements in the subjects' body composition, left ventricular ejection fraction, heart rate at rest, maximal oxygen uptake and ventilatory threshold. However, the HIIT group achieved better results than those in the MICT group, as it was evaluated by the amount of the effect size. The control group did not achieve any change in all of the measured variables. The tangible results achieved by our relatively large groups of homogeneous subjects have demonstrated that the HIIT program is an effective measure for the treatment of young women who are overweight.

Effects of High Intensity Interval Training and Strength Training on Metabolic, Cardiovascular and Hormonal Outcomes in Women with Polycystic Ovary Syndrome: A Pilot Study.

PubMed

Almenning, Ida; Rieber-Mohn, Astrid; Lundgren, Kari Margrethe; Shetelig Løvvik, Tone; Garnæs, Kirsti Krohn; Moholdt, Trine

2015-01-01

Polycystic ovary syndrome is a common endocrinopathy in reproductive-age women, and associates with insulin resistance. Exercise is advocated in this disorder, but little knowledge exists on the optimal exercise regimes. We assessed the effects of high intensity interval training and strength training on metabolic, cardiovascular, and hormonal outcomes in women with polycystic ovary syndrome. Three-arm parallel randomized controlled trial. Thirty-one women with polycystic ovary syndrome (age 27.2 ± 5.5 years; body mass index 26.7 ± 6.0 kg/m2) were randomly assigned to high intensity interval training, strength training, or a control group. The exercise groups exercised three times weekly for 10 weeks. The main outcome measure was change in homeostatic assessment of insulin resistance (HOMA-IR). HOMA-IR improved significantly only after high intensity interval training, by -0.83 (95% confidence interval [CI], -1.45, -0.20), equal to 17%, with between-group difference (p = 0.014). After high intensity interval training, high-density lipoprotein cholesterol increased by 0.2 (95% CI, 0.02, 0.5) mmol/L, with between group difference (p = 0.04). Endothelial function, measured as flow-mediated dilatation of the brachial artery, increased significantly after high intensity interval training, by 2.0 (95% CI, 0.1, 4.0) %, between-group difference (p = 0.08). Fat percentage decreased significantly after both exercise regimes, without changes in body weight. After strength training, anti-Müllarian hormone was significantly reduced, by -14.8 (95% CI, -21.2, -8.4) pmol/L, between-group difference (p = 0.04). There were no significant changes in high-sensitivity C-reactive protein, adiponectin or leptin in any group. High intensity interval training for ten weeks improved insulin resistance, without weight loss, in women with polycystic ovary syndrome. Body composition improved significantly after both strength training and high intensity interval training. This pilot study indicates that exercise training can improve the cardiometabolic profile in polycystic ovary syndrome in the absence of weight loss. ClinicalTrial.gov NCT01919281.

The kinetics of lactate production and removal during whole-body exercise

PubMed Central

2012-01-01

Background Based on a literature review, the current study aimed to construct mathematical models of lactate production and removal in both muscles and blood during steady state and at varying intensities during whole-body exercise. In order to experimentally test the models in dynamic situations, a cross-country skier performed laboratory tests while treadmill roller skiing, from where work rate, aerobic power and blood lactate concentration were measured. A two-compartment simulation model for blood lactate production and removal was constructed. Results The simulated and experimental data differed less than 0.5 mmol/L both during steady state and varying sub-maximal intensities. However, the simulation model for lactate removal after high exercise intensities seems to require further examination. Conclusions Overall, the simulation models of lactate production and removal provide useful insight into the parameters that affect blood lactate response, and specifically how blood lactate concentration during practical training and testing in dynamical situations should be interpreted. PMID:22413898

Effects of High-Intensity Interval and Moderate-Intensity Continuous Exercise on Inflammatory, Leptin, IgA, and Lipid Peroxidation Responses in Obese Males.

PubMed

de Souza, Daniel C; Matos, Victor A F; Dos Santos, Victor O A; Medeiros, Italo F; Marinho, Cristiane S R; Nascimento, Paulo R P; Dorneles, Gilson P; Peres, Alessandra; Müller, Carlos H; Krause, Maurício; Costa, Eduardo C; Fayh, Ana P T

2018-01-01

Purpose: To compare the effects of a single high-intensity interval exercise session (HIIE) with a moderate-intensity continuous exercise session (MICE) on the inflammatory profile, IgA levels, and lipid peroxidation in sedentary obese males. Methods: Ten sedentary obese men (age 28.5 ± 2.7 years; BMI 35.9 ± 4.9 kg/m 2 ; body fat 40.6 ± 2.0%) performed three experimental sessions, on separate days with 1 week wash-out period between interventions, according to a randomized order: (1) HIIE: 10 × 60 s at 90% of the HR max alternated by 60 s of active recovery; (2) MICE: 20 min at 70% of the HR max; (3) Rest-control. Blood and saliva samples were collected before, immediately after and 60 min after the end of each session in order to analyse serum levels of cytokines, IgA, and lipoperoxidation markers. Results: Leptin levels decreased immediately after HIIE ( P = 0.033) and was different from the MICE ( P = 0.025). IFN-γ levels were reduced immediately after ( P = 0.032) and 60 min after HIIE ( P = 0.003) compared to baseline, and it also increased IL-4 levels immediately after exercise ( P = 0.007) compared to resting values. MICE promoted an increase in IFN-γ levels immediately after exercise ( P = 0.025) and 60 min after exercise ( P = 0.004) in relation to baseline. Both exercise conditions increased IL-6 levels up to 60 min after exercise ( P < 0.05). The IFN-γ/IL-4 ratio decreased immediately after ( P = 0.002) and 60 min after HIIE ( P = 0.005) in relation to pre-exercise. No changes were found for IgA-S and TBARS for any of the conditions. Conclusion: A single HIIE session is able to decrease IFN-γ/IL-4 ratio, indicating an anti-inflammatory response, without alterations in the function of the mucosal immune system and lipoperoxidation. On the other hand, a brief session of MICE induced changes in the pattern of cytokines associated with increased cellular immune function.

Effects of High-Intensity Interval and Moderate-Intensity Continuous Exercise on Inflammatory, Leptin, IgA, and Lipid Peroxidation Responses in Obese Males

PubMed Central

de Souza, Daniel C.; Matos, Victor A. F.; dos Santos, Victor O. A.; Medeiros, Italo F.; Marinho, Cristiane S. R.; Nascimento, Paulo R. P.; Dorneles, Gilson P.; Peres, Alessandra; Müller, Carlos H.; Krause, Maurício; Costa, Eduardo C.; Fayh, Ana P. T.

2018-01-01

Purpose: To compare the effects of a single high-intensity interval exercise session (HIIE) with a moderate-intensity continuous exercise session (MICE) on the inflammatory profile, IgA levels, and lipid peroxidation in sedentary obese males. Methods: Ten sedentary obese men (age 28.5 ± 2.7 years; BMI 35.9 ± 4.9 kg/m2; body fat 40.6 ± 2.0%) performed three experimental sessions, on separate days with 1 week wash-out period between interventions, according to a randomized order: (1) HIIE: 10 × 60 s at 90% of the HRmax alternated by 60 s of active recovery; (2) MICE: 20 min at 70% of the HRmax; (3) Rest—control. Blood and saliva samples were collected before, immediately after and 60 min after the end of each session in order to analyse serum levels of cytokines, IgA, and lipoperoxidation markers. Results: Leptin levels decreased immediately after HIIE (P = 0.033) and was different from the MICE (P = 0.025). IFN-γ levels were reduced immediately after (P = 0.032) and 60 min after HIIE (P = 0.003) compared to baseline, and it also increased IL-4 levels immediately after exercise (P = 0.007) compared to resting values. MICE promoted an increase in IFN-γ levels immediately after exercise (P = 0.025) and 60 min after exercise (P = 0.004) in relation to baseline. Both exercise conditions increased IL-6 levels up to 60 min after exercise (P < 0.05). The IFN-γ/IL-4 ratio decreased immediately after (P = 0.002) and 60 min after HIIE (P = 0.005) in relation to pre-exercise. No changes were found for IgA-S and TBARS for any of the conditions. Conclusion: A single HIIE session is able to decrease IFN-γ/IL-4 ratio, indicating an anti-inflammatory response, without alterations in the function of the mucosal immune system and lipoperoxidation. On the other hand, a brief session of MICE induced changes in the pattern of cytokines associated with increased cellular immune function. PMID:29875681

The influence of training characteristics on the effect of aerobic exercise training in patients with chronic heart failure: A meta-regression analysis.

PubMed

Vromen, T; Kraal, J J; Kuiper, J; Spee, R F; Peek, N; Kemps, H M

2016-04-01

Although aerobic exercise training has shown to be an effective treatment for chronic heart failure patients, there has been a debate about the design of training programs and which training characteristics are the strongest determinants of improvement in exercise capacity. Therefore, we performed a meta-regression analysis to determine a ranking of the individual effect of the training characteristics on the improvement in exercise capacity of an aerobic exercise training program in chronic heart failure patients. We focused on four training characteristics; session frequency, session duration, training intensity and program length, and their product; total energy expenditure. A systematic literature search was performed for randomized controlled trials comparing continuous aerobic exercise training with usual care. Seventeen unique articles were included in our analysis. Total energy expenditure appeared the only training characteristic with a significant effect on improvement in exercise capacity. However, the results were strongly dominated by one trial (HF-action trial), accounting for 90% of the total patient population and showing controversial results compared to other studies. A repeated analysis excluding the HF-action trial confirmed that the increase in exercise capacity is primarily determined by total energy expenditure, followed by session frequency, session duration and session intensity. These results suggest that the design of a training program requires high total energy expenditure as a main goal. Increases in training frequency and session duration appear to yield the largest improvement in exercise capacity. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Higher exercise intensity delays postexercise recovery of impedance-derived cardiac sympathetic activity.

PubMed

Michael, Scott; Jay, Ollie; Graham, Kenneth S; Davis, Glen M

2017-08-01

Systolic time intervals (STIs) provide noninvasive insights into cardiac sympathetic neural activity (cSNA). As the effect of exercise intensity on postexercise STI recovery is unclear, this study investigated the STI recovery profile after different exercise intensities. Eleven healthy males cycled for 8 min at 3 separate intensities: LOW (40%-45%), MOD (75%-80%), and HIGH (90%-95%) of heart-rate (HR) reserve. Bio-impedance cardiography was used to assess STIs - primarily pre-ejection period (PEP; inversely correlated with cSNA), as well as left ventricular ejection time (LVET) and PEP:LVET - during 10 min seated recovery immediately postexercise. Heart-rate variability (HRV), i.e., natural-logarithm of root mean square of successive differences (Ln-RMSSD), was calculated as an index of cardiac parasympathetic neural activity (cPNA). Higher preceding exercise intensity elicited a slower recovery of HR and Ln-RMSSD (p < 0.001), and these measures did not return to baseline by 10 min following any intensity (p ≤ 0.009). Recovery of STIs was also slower following higher intensity exercise (p ≤ 0.002). By 30 s postexercise, higher preceding intensity resulted in a lower PEP (98 ± 14 ms, 75 ± 6 ms, 66 ± 5 ms for LOW, MOD, and HIGH, respectively, p < 0.001). PEP recovered to baseline (143 ± 11 ms) by 5 min following LOW (139 ± 13 ms, p = 0.590) and by 10 min following MOD (145 ± 17 ms, p = 0.602), but was still suppressed at 10 min following HIGH (123 ± 21 ms, p = 0.012). Higher preceding exercise intensity attenuated the recovery of indices for cSNA (from STIs) and cPNA (from HRV) in a graded dose-response fashion. While exercise intensity must be considered, acute recovery may be a valuable period during which to concurrently monitor these noninvasive indices, to identify potentially abnormal cardiac autonomic responses.

Differences in the Intensity and Duration of Adolescents' Sports and Exercise across Physical and Social Environments

ERIC Educational Resources Information Center

Dunton, Genevieve Fridlund; Berrigan, David; Ballard-Barbash, Rachel; Perna, Frank; Graubard, Barry I.; Atienza, Audie A.

2012-01-01

We used data from the American Time Use Survey (years 2003-06) to analyze whether the intensity and duration of high school students' (ages 15-18 years) sports and exercise bouts differed across physical and social environments. Boys' sports and exercise bouts were more likely to reach a vigorous intensity when taking place at school and with…

Within-session responses to high-intensity interval training in spinal cord injury.

PubMed

Astorino, Todd Anthony; Thum, Jacob S

2018-02-01

Completion of high-intensity interval training (HIIT) increases maximal oxygen uptake and health status, yet its feasibility in persons with spinal cord injury is unknown. To compare changes in cardiorespiratory and metabolic variables between two interval training regimes and moderate intensity exercise. Nine adults with spinal cord injury (duration = 6.8 ± 6.2 year) initially underwent determination of peak oxygen uptake. During subsequent sessions, they completed moderate intensity exercise, HIIT, or sprint interval training. Oxygen uptake, heart rate, and blood lactate concentration were measured. Oxygen uptake and heart rate increased (p < 0.05) during both interval training sessions and were similar (p > 0.05) to moderate intensity exercise. Peak oxygen uptake and heart rate were higher (p < 0.05) with HIIT (90% peak oxygen uptake and 99% peak heart rate) and sprint interval training (80% peak oxygen uptake and 96% peak heart rate) versus moderate intensity exercise. Despite a higher intensity and peak cardiorespiratory strain, all participants preferred interval training versus moderate exercise. Examining long-term efficacy and feasibility of interval training in this population is merited, considering that exercise intensity is recognized as the most important variable factor of exercise programming to optimize maximal oxygen uptake. Implications for Rehabilitation Spinal cord injury (SCI) reduces locomotion which impairs voluntary physical activity, typically resulting in a reduction in peak oxygen uptake and enhanced chronic disease risk. In various able-bodied populations, completion of high-intensity interval training (HIIT) has been consistently reported to improve cardiorespiratory fitness and other health-related outcomes, although its efficacy in persons with SCI is poorly understood. Data from this study in 9 men and women with SCI show similar changes in oxygen uptake and heart in response to HIIT compared to a prolonged bout of aerobic exercise, although peak values were higher in response to HIIT. Due to the higher peak metabolic strain induced by HIIT as well as universal preference for this modality versus aerobic exercise as reported in this study, further work testing utility of HIIT in this population is merited.

DIFFERENT RECOVERY METHODS AND MUSCLE PERFORMANCE AFTER EXHAUSTING EXERCISE: COMPARISON OF THE EFFECTS OF ELECTRICAL MUSCLE STIMULATION AND MASSAGE

PubMed Central

Kaya, F.; Bicer, B.; Erzeybek, M.S.; Cotuk, H.B.

2012-01-01

In this study we assessed the influence of the three different recovery interventions massage (MSG), electrical muscle stimulation (EMS), and passive rest (PR) on lactate disappearance and muscle recovery after exhausting exercise bouts. Twelve healthy male sport students participated in the study. They attended the laboratory on five test days. After measurement of V.O2max and a baseline Wingate test (WGb), the three recovery interventions were tested in random counterbalanced order. High intensity exercise, which consisted of six exhausting exercise bouts (interspersed with active recovery), was followed by MSG, EMS or PR application (24 minutes); then the final Wingate test (WGf) was performed. Lactate, heart rate, peak and mean power, rating of perceived exertion (RPE), and total quality of recovery (TQR) were recorded. In WGf mean power was significantly higher than in WGb for all three recovery modalities (MSG 6.29%, EMS 5.33%, PR 4.84% increase, p < 0.05), but no significant differences in mean and peak power were observed between the three recovery modes (p > 0.05). The heart rate response and the changes in blood lactate concentration were identical in all three interventions during the entire protocol (p = 0.817, p = 0.493, respectively). RPE and TQR scores were also not different among the three interventions (p > 0.05). These results provide further evidence that MSG and EMS are not more effective than PR in the process of recovery from high intensity exercise. PMID:24868117

Exercise intensities during a ballet lesson in female adolescents with different technical ability.

PubMed

Guidetti, L; Gallotta, M C; Emerenziani, G P; Baldari, C

2007-09-01

To investigate the exercise intensity during a typical grade five ballet lesson, thirty-nine dancers (13 - 16 yrs) were divided into three different technical proficiency groups: low level (n = 13), intermediate level (n = 14), and high level (n = 12). A progressively incremented treadmill test was administered to determine VO(2max), individual ventilatory threshold (IVT), and the individual anaerobic threshold (IAT). Oxygen uptake (VO(2)), heart rate (HR) and blood lactate (La) were then evaluated during a grade five ballet lesson. Oxygen uptake at IVT, IAT and maximal oxygen uptake were greater (p < 0.05) in the high-level dancers indicating a higher level of fitness. HR and %VO(2max) obtained during the various exercises of the ballet lesson were similar among groups. During the ballet lesson, low technical level dancers had more V.O (2) and La values above (p < 0.05) the IAT than the other groups. Correlation analysis revealed that the number of exercises performed above IAT was positively related to anthropometric characteristics (BMI, %FM; r = 0.36, p < 0.05; r = 0.46, p < 0.01), negatively related to fitness parameters (VO(2IVT), VO(2IAT), VO(2max); r between - 0.43 and - 0.69; p < 0.001) and to technical level (r = - 0.70; p < 0.001). The subjects classified as having low technical abilities had lower fitness levels and performed more exercises above IAT than the more skilled dancers.

Effects of prior warm-up regime on severe-intensity cycling performance.

PubMed

Burnley, Mark; Doust, Jonathan H; Jones, Andrew M

2005-05-01

The purpose of the present study was to determine the effect of three different warm-up regimes on cycling work output during a 7-min performance trial. After habituation to the experimental methods, 12 well-trained cyclists completed a series of 7-min performance trials, involving 2 min of constant-work rate exercise at approximately 90% VO2max and a further 5 min during which subjects attempted to maximize power output. This trial was performed without prior intervention and 10 min after bouts of moderate, heavy, or sprint exercise in a random order. Pulmonary gas exchange was measured breath by breath during all performance trials. At the onset of the performance trial, baseline blood [lactate] was significantly elevated after heavy and sprint but not moderate exercise (mean +/- SD: control, 1.0 +/- 0.3 mM; moderate, 1.0 +/- 0.2 mM; heavy, 3.0 +/- 1.1 mM; sprint, 5.9 +/- 1.5 mM). All three interventions significantly increased the amplitude of the primary VO2 response (control, 2.59 +/- 0.28 L x min(-1); moderate, 2.69 +/- 0.27 L x min(-1); heavy, 2.78 +/- 0.26 L x min(-1); sprint, 2.78 +/- 0.30 L x min(-1)). Mean power output was significantly increased by prior moderate and heavy exercise but not significantly reduced after sprint exercise (control, 330 +/- 42 W; moderate, 338 +/- 39 W; heavy, 339 +/- 42 W; sprint, 324 +/- 45 W). These data indicate that priming exercise performed in the moderate- and heavy-intensity domains can improve severe-intensity cycling performance by ~2-3%, the latter condition doing so despite a mild lactacidosis being present at exercise onset.

Manipulating Carbohydrate Availability Between Twice-Daily Sessions of High-Intensity Interval Training Over 2 Weeks Improves Time-Trial Performance.

PubMed

Cochran, Andrew J; Myslik, Frank; MacInnis, Martin J; Percival, Michael E; Bishop, David; Tarnopolsky, Mark A; Gibala, Martin J

2015-10-01

Commencing some training sessions with reduced carbohydrate (CHO) availability has been shown to enhance skeletal muscle adaptations, but the effect on exercise performance is less clear. We examined whether restricting CHO intake between twice daily sessions of high-intensity interval training (HIIT) augments improvements in exercise performance and mitochondrial content. Eighteen active but not highly trained subjects (peak oxygen uptake [VO2peak] = 44 ± 9 ml/kg/min), matched for age, sex, and fitness, were randomly allocated to two groups. On each of 6 days over 2 weeks, subjects completed two training sessions, each consisting of 5 × 4-min cycling intervals (60% of peak power), interspersed by 2 min of recovery. Subjects ingested either 195 g of CHO (HI-HI group: ~2.3 g/kg) or 17 g of CHO (HI-LO group: ~0.3 g/kg) during the 3-hr period between sessions. The training-induced improvement in 250-kJ time trial performance was greater (p = .02) in the HI-LO group (211 ± 66 W to 244 ± 75 W) compared with the HI-HI group (203 ± 53 W to 219 ± 60 W); however, the increases in mitochondrial content was similar between groups, as reflected by similar increases in citrate synthase maximal activity, citrate synthase protein content and cytochrome c oxidase subunit IV protein content (p > .05 for interaction terms). This is the first study to show that a short-term "train low, compete high" intervention can improve whole-body exercise capacity. Further research is needed to determine whether this type of manipulation can also enhance performance in highly-trained subjects.

High Intensity Cycling Performances of Boys with and without Intellectual Disability.

ERIC Educational Resources Information Center

Chia, Y. H. M.; Lee, K. S.; Teo-Koh, S. M.

2002-01-01

Boys with (n=16) and without (n=18) intellectual disability (ID) performed the Wingate Anaerobic Test (WAnT) on two separate occasions. Comparable levels of reliability and agreement were found on the WAnT for both groups. However, the performances of boys with ID were more variable, less powerful, and resulted in lower post-exercise blood lactose…

The effects of exercise program on burnout and metabolic syndrome components in banking and insurance workers.

PubMed

Tsai, Han Hui; Yeh, Ching Ying; Su, Chien Tien; Chen, Chiou Jong; Peng, Shu Mei; Chen, Ruey Yu

2013-01-01

To explore the effectiveness of exercise program for banking and insurance workers and clarify the association between exercise, burnout, and metabolic syndrome components. In the process of the study, a practicable worksite exercise program was developed for bank and insurance enterprises. A three-month (12-wk) exercise course was conducted, and its benefits evaluated. Levels of burnout and metabolic syndrome components were analyzed after exercise intervention. After intervention, the indicators of burnout and metabolic syndrome components were significantly improved in both low and high intensity groups, and the improvement were expressed in reduction of waist circumference, systolic blood pressure, person burnout and work-related burnout. A dose-response of burnouts and metabolic syndrome components with exercise intensity are shown (p<0.05). Metabolic syndrome components were independently associated with burnout and exercise intensity in the crude model. After adjustment for potential confounders, waist circumference and systolic blood pressure differences showed significant associations with exercise intensity (p<0.05). This study demonstrated an effective approach to worksite exercise intervention and exercise intensity played an important role to alleviate damage between burnouts and metabolic syndrome components.

Effect of workplace- versus home-based physical exercise on pain in healthcare workers: study protocol for a single blinded cluster randomized controlled trial

PubMed Central

2014-01-01

Background The prevalence and consequences of musculoskeletal pain is considerable among healthcare workers, allegedly due to high physical work demands of healthcare work. Previous investigations have shown promising results of physical exercise for relieving pain among different occupational groups, but the question remains whether such physical exercise should be performed at the workplace or conducted as home-based exercise. Performing physical exercise at the workplace together with colleagues may be more motivating for some employees and thus increase adherence. On the other hand, physical exercise performed during working hours at the workplace may be costly for the employers in terms of time spend. Thus, it seems relevant to compare the efficacy of workplace- versus home-based training on musculoskeletal pain. This study is intended to investigate the effect of workplace-based versus home-based physical exercise on musculoskeletal pain among healthcare workers. Methods/Design This study was designed as a cluster randomized controlled trial performed at 3 hospitals in Copenhagen, Denmark. Clusters are hospital departments and hospital units. Cluster randomization was chosen to increase adherence and avoid contamination between interventions. Two hundred healthcare workers from 18 departments located at three different hospitals is allocated to 10 weeks of 1) workplace based physical exercise performed during working hours (using kettlebells, elastic bands and exercise balls) for 5 × 10 minutes per week and up to 5 group-based coaching sessions, or 2) home based physical exercise performed during leisure time (using elastic bands and body weight exercises) for 5 × 10 minutes per week. Both intervention groups will also receive ergonomic instructions on patient handling and use of lifting aides etc. Inclusion criteria are female healthcare workers working at a hospital. Average pain intensity (VAS scale 0-10) of the back, neck and shoulder (primary outcome) and physical exertion during work, social capital and work ability (secondary outcomes) is assessed at baseline and 10-week follow-up. Further, postural balance and mechanical muscle function is assessed during clinical examination at baseline and follow-up. Discussion This cluster randomized trial will investigate the change in self-rated average pain intensity in the back, neck and shoulder after either 10 weeks of physical exercise at the workplace or at home. Trial registration ClinicalTrials.gov (NCT01921764). PMID:24708570

Effect of workplace- versus home-based physical exercise on pain in healthcare workers: study protocol for a single blinded cluster randomized controlled trial.

PubMed

Jakobsen, Markus D; Sundstrup, Emil; Brandt, Mikkel; Kristensen, Anne Zoëga; Jay, Kenneth; Stelter, Reinhard; Lavendt, Ebbe; Aagaard, Per; Andersen, Lars L

2014-04-07

The prevalence and consequences of musculoskeletal pain is considerable among healthcare workers, allegedly due to high physical work demands of healthcare work. Previous investigations have shown promising results of physical exercise for relieving pain among different occupational groups, but the question remains whether such physical exercise should be performed at the workplace or conducted as home-based exercise. Performing physical exercise at the workplace together with colleagues may be more motivating for some employees and thus increase adherence. On the other hand, physical exercise performed during working hours at the workplace may be costly for the employers in terms of time spend. Thus, it seems relevant to compare the efficacy of workplace- versus home-based training on musculoskeletal pain. This study is intended to investigate the effect of workplace-based versus home-based physical exercise on musculoskeletal pain among healthcare workers. This study was designed as a cluster randomized controlled trial performed at 3 hospitals in Copenhagen, Denmark. Clusters are hospital departments and hospital units. Cluster randomization was chosen to increase adherence and avoid contamination between interventions. Two hundred healthcare workers from 18 departments located at three different hospitals is allocated to 10 weeks of 1) workplace based physical exercise performed during working hours (using kettlebells, elastic bands and exercise balls) for 5 × 10 minutes per week and up to 5 group-based coaching sessions, or 2) home based physical exercise performed during leisure time (using elastic bands and body weight exercises) for 5 × 10 minutes per week. Both intervention groups will also receive ergonomic instructions on patient handling and use of lifting aides etc. Inclusion criteria are female healthcare workers working at a hospital. Average pain intensity (VAS scale 0-10) of the back, neck and shoulder (primary outcome) and physical exertion during work, social capital and work ability (secondary outcomes) is assessed at baseline and 10-week follow-up. Further, postural balance and mechanical muscle function is assessed during clinical examination at baseline and follow-up. This cluster randomized trial will investigate the change in self-rated average pain intensity in the back, neck and shoulder after either 10 weeks of physical exercise at the workplace or at home. ClinicalTrials.gov (NCT01921764).

Effects of Aerobic Exercise on Mild Cognitive Impairment

PubMed Central

Baker, Laura D.; Frank, Laura L.; Foster-Schubert, Karen; Green, Pattie S.; Wilkinson, Charles W.; McTiernan, Anne; Plymate, Stephen R.; Fishel, Mark A.; Stennis Watson, G.; Cholerton, Brenna A.; Duncan, Glen E.; Mehta, Pankaj D.; Craft, Suzanne

2011-01-01

Objectives To examine the effects of aerobic exercise on cognition and other biomarkers associated with Alzheimer disease pathology for older adults with mild cognitive impairment, and assess the role of sex as a predictor of response. Design Six-month, randomized, controlled, clinical trial. Setting Veterans Affairs Puget Sound Health Care System clinical research unit. Participants Thirty-three adults (17 women) with amnestic mild cognitive impairment ranging in age from 55 to 85 years (mean age,70 years). Intervention Participants were randomized either to a high-intensity aerobic exercise or stretching control group. The aerobic group exercised under the supervision of a fitness trainer at 75% to 85% of heart rate reserve for 45 to 60 min/d, 4 d/wk for 6 months. The control group carried out supervised stretching activities according to the same schedule but maintained their heart rate at or below 50% of their heart rate reserve. Before and after the study, glucometabolic and treadmill tests were performed and fat distribution was assessed using dual-energy x-ray absorptiometry. At baseline, month 3, and month 6, blood was collected for assay and cognitive tests were administered. Main Outcome Measures Performance measures on Symbol-Digit Modalities, Verbal Fluency, Stroop, Trails B, Task Switching, Story Recall, and List Learning. Fasting plasma levels of insulin, cortisol, brain-derived neurotrophic factor, insulinlike growth factor-I, and β-amyloids 40 and 42. Results Six months of high-intensity aerobic exercise had sex-specific effects on cognition, glucose metabolism, and hypothalamic-pituitary-adrenal axis and trophic activity despite comparable gains in cardiorespiratory fitness and body fat reduction. For women, aerobic exercise improved performance on multiple tests of executive function, increased glucose disposal during the metabolic clamp, and reduced fasting plasma levels of insulin, cortisol, and brain-derived neurotrophic factor. For men, aerobic exercise increased plasma levels of insulinlike growth factor I and had a favorable effect only on Trails B performance. Conclusions This study provides support, using rigorous controlled methodology, for a potent nonpharma-cologic intervention that improves executive control processes for older women at high risk of cognitive decline. Moreover, our results suggest that a sex bias in cognitive response may relate to sex-based differences in glucometabolic and hypothalamic-pituitary-adrenal axis responses to aerobic exercise. PMID:20065132

Effects of aerobic exercise on mild cognitive impairment: a controlled trial.

PubMed

Baker, Laura D; Frank, Laura L; Foster-Schubert, Karen; Green, Pattie S; Wilkinson, Charles W; McTiernan, Anne; Plymate, Stephen R; Fishel, Mark A; Watson, G Stennis; Cholerton, Brenna A; Duncan, Glen E; Mehta, Pankaj D; Craft, Suzanne

2010-01-01

To examine the effects of aerobic exercise on cognition and other biomarkers associated with Alzheimer disease pathology for older adults with mild cognitive impairment, and assess the role of sex as a predictor of response. Six-month, randomized, controlled, clinical trial. Veterans Affairs Puget Sound Health Care System clinical research unit. Thirty-three adults (17 women) with amnestic mild cognitive impairment ranging in age from 55 to 85 years (mean age, 70 years). Intervention Participants were randomized either to a high-intensity aerobic exercise or stretching control group. The aerobic group exercised under the supervision of a fitness trainer at 75% to 85% of heart rate reserve for 45 to 60 min/d, 4 d/wk for 6 months. The control group carried out supervised stretching activities according to the same schedule but maintained their heart rate at or below 50% of their heart rate reserve. Before and after the study, glucometabolic and treadmill tests were performed and fat distribution was assessed using dual-energy x-ray absorptiometry. At baseline, month 3, and month 6, blood was collected for assay and cognitive tests were administered. Performance measures on Symbol-Digit Modalities, Verbal Fluency, Stroop, Trails B, Task Switching, Story Recall, and List Learning. Fasting plasma levels of insulin, cortisol, brain-derived neurotrophic factor, insulinlike growth factor-I, and beta-amyloids 40 and 42. Six months of high-intensity aerobic exercise had sex-specific effects on cognition, glucose metabolism, and hypothalamic-pituitary-adrenal axis and trophic activity despite comparable gains in cardiorespiratory fitness and body fat reduction. For women, aerobic exercise improved performance on multiple tests of executive function, increased glucose disposal during the metabolic clamp, and reduced fasting plasma levels of insulin, cortisol, and brain-derived neurotrophic factor. For men, aerobic exercise increased plasma levels of insulinlike growth factor I and had a favorable effect only on Trails B performance. This study provides support, using rigorous controlled methodology, for a potent nonpharmacologic intervention that improves executive control processes for older women at high risk of cognitive decline. Moreover, our results suggest that a sex bias in cognitive response may relate to sex-based differences in glucometabolic and hypothalamic-pituitary-adrenal axis responses to aerobic exercise.

Impact of a carbohydrate-electrolyte drink on ingestive behaviour, affect and self-selected intensity during recreational exercise after 24-h fluid restriction.

PubMed

Peacock, Oliver J; Thompson, Dylan; Stokes, Keith A

2013-01-01

This study examined the effects of a carbohydrate-electrolyte drink on voluntary fluid intake, affect and self-selected intensity during recreational exercise after fluid restriction. In a randomised counterbalanced design, ten physically active adults were dehydrated via a 24-h period of fluid restriction before completing two 20-min bouts of cardiovascular exercise, 20-min of resistance exercise and 20 min on a cycle ergometer at a self-selected intensity with ad libitum access to water (W) or a carbohydrate-electrolyte solution (CES). Fluid restriction induced hypohydration of ∼1.2% initial body mass. Fluid intake during exercise was greater with CES (2105 ± 363 vs. 1470 ± 429 mL; P<0.01) and resulted in more adequate hydration (-0.03 ± 0.65 vs. -1.26 ± 0.80%; P<0.01). Plasma glucose concentrations (4.48 ± 0.40 vs. 4.28 ± 0.32 mmol L(-1); P<0.01) and pleasure ratings (2.63 ± 1.17 vs. 1.81 ± 1.37; P<0.01) were greater with CES than W. Mean power output during exercise performed at a self-selected intensity was 5.6% greater with CES (171 ± 63 vs. 162 ± 60 W; P<0.05). In physically active adults performing a 'real-life' recreational exercise simulation, CES resulted in more adequate hydration and an enhanced affective experience that corresponded with an increase in self-selected exercise intensity. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effects of high-intensity interval training on central haemodynamics and skeletal muscle oxygenation during exercise in patients with chronic heart failure.

PubMed

Spee, Ruud F; Niemeijer, Victor M; Wijn, Pieter F; Doevendans, Pieter A; Kemps, Hareld M

2016-12-01

Background High-intensity interval training (HIT) improves exercise capacity in patients with chronic heart failure (CHF). Moreover, HIT was associated with improved resting cardiac function. However, the extent to which these improvements actually contribute to training-induced changes in exercise capacity remains to be elucidated. Therefore, we evaluated the effects of HIT on exercising central haemodynamics and skeletal muscle oxygenation. Methods Twenty-six CHF patients were randomised to a 12-week 4 × 4 minute HIT program at 85-95% of peak VO 2 or usual care. Patients performed maximal and submaximal cardiopulmonary exercise testing with simultaneous assessment of cardiac output and skeletal muscle oxygenation by near infrared spectroscopy, using the amplitude of the tissue saturation index (TSIamp). Results Peak workload increased by 11% after HIT ( p between group = 0.01) with a non-significant increase in peak VO 2 (+7%, p between group = 0.19). Cardiac reserve increased by 37% after HIT ( p within group = 0.03, p between group = 0.08); this increase was not related to improvements in peak workload. Oxygen uptake recovery kinetics after submaximal exercise were accelerated by 20% ( p between group = 0.02); this improvement was related to a decrease in TSIamp ( r = 0.71, p = 0.03), but not to changes in cardiac output kinetics. Conclusion HIT induced improvements in maximal exercise capacity and exercising haemodynamics at peak exercise. Improvements in recovery after submaximal exercise were associated with attenuated skeletal muscle deoxygenation during submaximal exercise, but not with changes in cardiac output kinetics, suggesting that the effect of HIT on submaximal exercise capacity is mediated by improved microvascular oxygen delivery-to-utilisation matching.

Short-Term Intensified Cycle Training Alters Acute and Chronic Responses of PGC1α and Cytochrome C Oxidase IV to Exercise in Human Skeletal Muscle

PubMed Central

Stepto, Nigel K.; Benziane, Boubacar; Wadley, Glenn D.; Chibalin, Alexander V.; Canny, Benedict J.; Eynon, Nir; McConell, Glenn K.

2012-01-01

Reduced activation of exercise responsive signalling pathways have been reported in response to acute exercise after training; however little is known about the adaptive responses of the mitochondria. Accordingly, we investigated changes in mitochondrial gene expression and protein abundance in response to the same acute exercise before and after 10-d of intensive cycle training. Nine untrained, healthy participants (mean±SD; VO2peak 44.1±17.6 ml/kg/min) performed a 60 min bout of cycling exercise at 164±18 W (72% of pre-training VO2peak). Muscle biopsies were obtained from the vastus lateralis muscle at rest, immediately and 3 h after exercise. The participants then underwent 10-d of cycle training which included four high-intensity interval training sessions (6×5 min; 90–100% VO2peak) and six prolonged moderate-intensity sessions (45–90 min; 75% VO2peak). Participants repeated the pre-training exercise trial at the same absolute work load (64% of pre-training VO2peak). Muscle PGC1-α mRNA expression was attenuated as it increased by 11- and 4- fold (P<0.001) after exercise pre- and post-training, respectively. PGC1-α protein expression increased 1.5 fold (P<0.05) in response to exercise pre-training with no further increases after the post-training exercise bout. RIP140 protein abundance was responsive to acute exercise only (P<0.01). COXIV mRNA (1.6 fold; P<0.01) and COXIV protein expression (1.5 fold; P<0.05) were increased by training but COXIV protein expression was decreased (20%; P<0.01) by acute exercise pre- and post-training. These findings demonstrate that short-term intensified training promotes increased mitochondrial gene expression and protein abundance. Furthermore, acute indicators of exercise-induced mitochondrial adaptation appear to be blunted in response to exercise at the same absolute intensity following short-term training. PMID:23285255

High-intensity interval training and calorie restriction promote remodeling of glucose and lipid metabolism in diet-induced obesity.

PubMed

Davis, Rachel A H; Halbrooks, Jacob E; Watkins, Emily E; Fisher, Gordon; Hunter, Gary R; Nagy, Tim R; Plaisance, Eric P

2017-08-01

Calorie restriction (CR) decreases adiposity, but the magnitude and defense of weight loss is less than predicted due to reductions in total daily energy expenditure (TEE). The purpose of the current investigation was to determine whether high-intensity interval training (HIIT) would increase markers of sympathetic activation in white adipose tissue (WAT) and rescue CR-mediated reductions in EE to a greater extent than moderate-intensity aerobic exercise training (MIT). Thirty-two 5-wk-old male C57BL/6J mice were placed on ad libitum HFD for 11 wk, followed by randomization to one of four groups ( n = 8/group) for an additional 15 wk: 1 ) CON (remain on HFD), 2 ) CR (25% lower energy intake), 3 ) CR + HIIT (25% energy deficit created by 12.5% CR and 12.5% EE through HIIT), and 4 ) CR + MIT (25% energy deficit created by 12.5% CR and 12.5% EE through MIT). Markers of adipose thermogenesis ( Ucp1 , Prdm16 , Dio2 , and Fgf21 ) were unchanged in either exercise group in inguinal or epididymal WAT, whereas CR + HIIT decreased Ucp1 expression in retroperitoneal WAT and brown adipose tissue. HIIT rescued CR-mediated reductions in lean body mass (LBM) and resting energy expenditure (REE), and both were associated with improvements in glucose/insulin tolerance. Improvements in glucose metabolism in the CR + HIIT group appear to be linked to a molecular signature that enhances glucose and lipid storage in skeletal muscle. Exercise performed at either moderate or high intensity does not increase markers of adipose thermogenesis when performed in the presence of CR but remodels skeletal muscle metabolic and thermogenic capacity. Copyright © 2017 the American Physiological Society.

[Effects of 12 sessions of high intensity intermittent training and nutrition counseling on body fat in obese and overweight participants].

PubMed

Molina, Catalina; Cifuentes, Gabriela; Martínez, Cristian; Mancilla, Rodrigo; Díaz, Erik

2016-10-01

The search of efficient exercise alternatives to treat obesity is worthwhile. To demonstrate the effect of high intensity intermittent exercise on body fat reduction in overweight and obese subjects. A group of 65 overweight and obese adult subjects (25 men), aged 18-65 years, participated during 12 sessions in a high intensity physical exercise program, 3 days/week. Weight, height and body fat was measured before and after the intervention by bioimpedance. Each session consisted of 1 min stationary cycling exercise at high intensity, followed by 2 min inactive rest. This cycle was repeated 10 times, thus the method is called 1*2*10. There was a significant reduction of body fat of -1.88 ± 2.8 and -3.44 ± 2.7 kg, in women and men, respectively (p < 0.05). The 1*2*10 training protocol lasting 12 weeks in association with nutrition counseling is effective in reducing body fat in overweight persons.

The effects of high intensity short rest resistance exercise on muscle damage markers in men and women.

PubMed

Heavens, Kristen R; Szivak, Tunde K; Hooper, David R; Dunn-Lewis, Courtenay; Comstock, Brett A; Flanagan, Shawn D; Looney, David P; Kupchak, Brian R; Maresh, Carl M; Volek, Jeff S; Kraemer, William J

2014-04-01

Within and between sexes, universal load prescription (as assigned in extreme conditioning programs) creates extreme ranges in individual training intensities. Exercise intensity has been proposed to be the main factor determining the degree of muscle damage. Thus, the purpose of this study was to examine markers of muscle damage in resistance-trained men (n = 9) and women (n = 9) from a high intensity (HI) short rest (SR) (HI/SR) resistance exercise protocol. The HI/SR consisted of a descending pyramid scheme starting at 10 repetitions, decreasing 1 repetition per set for the back squat, bench press, and deadlift, as fast as possible. Blood was drawn pre-exercise (pre), immediately postexercise (IP), 15 minutes postexercise (+15), 60 minutes postexercise (+60), and 24 hours postexercise (+24). Women demonstrated significant increases in interleukin 6 (IL-6; IP), creatine kinase (CK; +24), myoglobin (IP, +15, +60), and a greater relative increase when compared with men (+15, +60). Men demonstrated significant increases in myoglobin (IP, +15, +60, +24), IL-6 (IP, +15), CK (IP, +60, +24), and testosterone (IP, +15). There were significant sex interactions observed in CK (IP, +60, +24) and testosterone (IP, +15, +60, +24). Women completed the protocol faster (women: 34:04 ± 9:40 minutes, men: 39:22 ± 14:43 minutes), and at a slightly higher intensity (women: 70.1 ± 3.5%, men 68.8 ± 3.1%); however, men performed significantly more work (men: 14384.6 ± 1854.5 kg, women: 8774.7 ± 1612.7 kg). Overall, women demonstrated a faster inflammatory response with increased acute damage, whereas men demonstrated a greater prolonged damage response. Therefore, strength and conditioning professionals need to be aware of the level of stress imposed on individuals when creating such volitional high intensity metabolic type workouts and allow for adequate progression and recovery from such workouts.

Effect of resistance exercise intensity on the expression of PGC-1α isoforms and the anabolic and catabolic signaling mediators, IGF-1 and myostatin, in human skeletal muscle.

PubMed

Schwarz, Neil A; McKinley-Barnard, Sarah K; Spillane, Mike B; Andre, Thomas L; Gann, Joshua J; Willoughby, Darryn S

2016-08-01

The purpose of this study was to investigate the acute messenger (mRNA) expression of the peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) isoforms, insulin-like growth factor-1Ea (IGF-1Ea), and myostatin in response to 2 resistance exercise intensities. In a uniform-balanced, crossover design, 10 participants performed 2 separate testing sessions involving a lower body resistance exercise component consisting of a lower intensity (50% of 1-repetition maximum; 1RM) protocol and a higher intensity (80% of 1RM) protocol of equal volumes. Muscle samples were obtained at before exercise, 45 min, 3 h, 24 h, and 48 h postexercise. Resistance exercise did not alter total PGC-1α mRNA expression; however, distinct responses of each PGC-1α isoform were observed. The response of each isoform was consistent between sessions, suggesting no effect of resistance exercise intensity on the complex transcriptional expression of the PGC-1α gene. IGF-1Ea mRNA expression significantly increased following the higher intensity session compared with pre-exercise and the lower intensity session. Myostatin mRNA expression was significantly reduced compared with pre-exercise values at all time points with no difference between exercise intensity. Further research is needed to determine the effects of the various isoforms of PGC-1α in human skeletal muscle on the translational level as well as their relation to the expression of IGF-1 and myostatin.

Influence of music on performance and psychophysiological responses during moderate-intensity exercise preceded by fatigue.

PubMed

Lopes-Silva, Joao P; Lima-Silva, Adriano E; Bertuzzi, Romulo; Silva-Cavalcante, Marcos D

2015-02-01

We examined the effects of listening to music on time to exhaustion and psychophysiological responses during moderate-intensity exercise performed in fatigued and non-fatigued conditions. Fourteen healthy men performed moderate-intensity exercise (60% Wmax) until exhaustion under four different conditions: with and without pre-fatigue (induced by 100 drop jumps) and listening and not listening to music. Time to exhaustion was lower in the fatigued than the non-fatigued condition regardless listening to music. Similarly, RPE was higher in the fatigued than the non-fatigued condition, but music had no effect. On the other hand, listening to music decreased the associative thoughts regardless of fatigue status. Heart rate was not influenced by any treatment. These results suggest that listening to music changes attentional focus but is not able to reverse fatigue-derived alteration of performance. Copyright © 2014 Elsevier Inc. All rights reserved.

Classification of Physical Activity: Information to Artificial Pancreas Control Systems in Real Time.

PubMed

Turksoy, Kamuran; Paulino, Thiago Marques Luz; Zaharieva, Dessi P; Yavelberg, Loren; Jamnik, Veronica; Riddell, Michael C; Cinar, Ali

2015-10-06

Physical activity has a wide range of effects on glucose concentrations in type 1 diabetes (T1D) depending on the type (ie, aerobic, anaerobic, mixed) and duration of activity performed. This variability in glucose responses to physical activity makes the development of artificial pancreas (AP) systems challenging. Automatic detection of exercise type and intensity, and its classification as aerobic or anaerobic would provide valuable information to AP control algorithms. This can be achieved by using a multivariable AP approach where biometric variables are measured and reported to the AP at high frequency. We developed a classification system that identifies, in real time, the exercise intensity and its reliance on aerobic or anaerobic metabolism and tested this approach using clinical data collected from 5 persons with T1D and 3 individuals without T1D in a controlled laboratory setting using a variety of common types of physical activity. The classifier had an average sensitivity of 98.7% for physiological data collected over a range of exercise modalities and intensities in these subjects. The classifier will be added as a new module to the integrated multivariable adaptive AP system to enable the detection of aerobic and anaerobic exercise for enhancing the accuracy of insulin infusion strategies during and after exercise. © 2015 Diabetes Technology Society.

Classification of Physical Activity

PubMed Central

Turksoy, Kamuran; Paulino, Thiago Marques Luz; Zaharieva, Dessi P.; Yavelberg, Loren; Jamnik, Veronica; Riddell, Michael C.; Cinar, Ali

2015-01-01

Physical activity has a wide range of effects on glucose concentrations in type 1 diabetes (T1D) depending on the type (ie, aerobic, anaerobic, mixed) and duration of activity performed. This variability in glucose responses to physical activity makes the development of artificial pancreas (AP) systems challenging. Automatic detection of exercise type and intensity, and its classification as aerobic or anaerobic would provide valuable information to AP control algorithms. This can be achieved by using a multivariable AP approach where biometric variables are measured and reported to the AP at high frequency. We developed a classification system that identifies, in real time, the exercise intensity and its reliance on aerobic or anaerobic metabolism and tested this approach using clinical data collected from 5 persons with T1D and 3 individuals without T1D in a controlled laboratory setting using a variety of common types of physical activity. The classifier had an average sensitivity of 98.7% for physiological data collected over a range of exercise modalities and intensities in these subjects. The classifier will be added as a new module to the integrated multivariable adaptive AP system to enable the detection of aerobic and anaerobic exercise for enhancing the accuracy of insulin infusion strategies during and after exercise. PMID:26443291

Cardiovascular response to exercise training in the systemic right ventricle of adults with transposition of the great arteries

PubMed Central

Shafer, K M; Janssen, L; Carrick-Ranson, G; Rahmani, S; Palmer, D; Fujimoto, N; Livingston, S; Matulevicius, S A; Forbess, L W; Brickner, B; Levine, B D

2015-01-01

We aimed to assess the haemodynamic effects of exercise training in transposition of the great arteries (TGA) patients with systemic right ventricles (SRVs). TGA patients have limited exercise tolerance and early mortality due to systemic (right) ventricular failure. Whether exercise training enhances or injures the SRV is unclear. Fourteen asymptomatic patients (34 ± 10 years) with TGA and SRV were enrolled in a 12 week exercise training programme (moderate and high-intensity workouts). Controls were matched on age, gender, BMI and physical activity. Exercise testing pre- and post- training included: (a) submaximal and peak; (b) prolonged (60 min) submaximal endurance and (c) high-intensity intervals. Oxygen uptake (; Douglas bag technique), cardiac output (, foreign-gas rebreathing), ventricular function (echocardiography and cardiac MRI) and serum biomarkers were assessed. TGA patients had lower peak , , and stroke volume (SV), a blunted / slope, and diminished SV response to exercise (SV increase from rest: TGA = 15.2%, controls = 68.9%, P < 0.001) compared with controls. After training, TGA patients increased peak by 6 ± 8.5%, similar to controls (interaction P = 0.24). The magnitude of SV reserve on initial testing correlated with training response (r = 0.58, P = 0.047), though overall, no change in peak was observed. High-sensitivity troponin T (hs-TnT) and N-terminal prohormone of brain naturetic peptide (NT pro-BNP) were low and did not change with acute exercise or after training. Our data show that TGA patients with SRVs in this study safely participated in exercise training and improved peak . Neither prolonged submaximal exercise, nor high-intensity intervals, nor short-term exercise training seem to injure the systemic right ventricle. Key Points Patients with transposition of the great arteries (TGA) and systemic right ventricles have premature congestive heart failure; there is also a growing concern that athletes who perform extraordinary endurance exercise may injure the right ventricle. Therefore we felt it essential to determine whether exercise training might injure a systemic right ventricle which is loaded with every heartbeat. Previous studies have shown that short term exercise training is feasible in TGA patients, but its effect on ventricular function is unclear. We demonstrate that systemic right ventricular function is preserved (and may be improved) in TGA patients with exercise training programmes that are typical of recreational and sports participation, with no evidence of injury on biomarker assessment. Stroke volume reserve during exercise correlates with exercise training response in our TGA patients, identifying this as a marker of a systemic right ventricle (SRV) that may most tolerate (and possibly even be improved by) exercise training. PMID:25809342

Improving the Accuracy of Predicting Maximal Oxygen Consumption (VO2pk)

NASA Technical Reports Server (NTRS)

Downs, Meghan E.; Lee, Stuart M. C.; Ploutz-Snyder, Lori; Feiveson, Alan

2016-01-01

Maximal oxygen (VO2pk) is the maximum amount of oxygen that the body can use during intense exercise and is used for benchmarking endurance exercise capacity. The most accurate method to determineVO2pk requires continuous measurements of ventilation and gas exchange during an exercise test to maximal effort, which necessitates expensive equipment, a trained staff, and time to set-up the equipment. For astronauts, accurate VO2pk measures are important to assess mission critical task performance capabilities and to prescribe exercise intensities to optimize performance. Currently, astronauts perform submaximal exercise tests during flight to predict VO2pk; however, while submaximal VO2pk prediction equations provide reliable estimates of mean VO2pk for populations, they can be unacceptably inaccurate for a given individual. The error in current predictions and logistical limitations of measuring VO2pk, particularly during spaceflight, highlights the need for improved estimation methods.

Exercise intensity and postprandial health outcomes in adolescents.

PubMed

Bond, Bert; Williams, Craig A; Isic, Carly; Jackman, Sarah R; Tolfrey, Keith; Barrett, Laura A; Barker, Alan R

2015-05-01

The effect of exercise intensity and sex on postprandial risk factors for cardiovascular disease in adolescents is unknown. We examined the effect of a single bout of work-matched high-intensity interval exercise (HIIE) and moderate-intensity exercise (MIE) on postprandial triacylglycerol (TAG) and systolic blood pressure (SBP) in adolescents. Twenty adolescents (10 male, 14.3 ± 0.3 years) completed three 1-day trials: (1) rest (CON); (2) 8 × 1 min cycling at 90 % peak power with 75 s recovery (HIIE); (3) cycling at 90 % of the gas exchange threshold (MIE), 1 h before consuming a high-fat milkshake (1.50 g fat and 80 kJ kg(-1)). Postprandial TAG, SBP and fat oxidation were assessed over 4 h Compared to CON, the incremental area under the curve for TAG (IAUC-TAG) was not significantly lowered in HIIE [P = 0.22, effect size (ES) = 0.24] or MIE (P = 0.65, ES = 0.04) for boys. For girls, HIIE and MIE lowered IAUC-TAG by 34 % (P = 0.02, ES = 0.58) and 38 % (P = 0.09, ES = 0.73), respectively, with no difference between HIIE and MIE (P = 0.74, ES = 0.14). Changes in TAG were not related to energy expenditure during exercise or postprandial fat oxidation. Postprandial SBP (total-AUC pooled for both sexes) was lower in HIIE compared to CON (P = 0.01, ES = 0.68) and MIE (P = 0.02, ES = 0.60), with no difference between MIE and CON (P = 0.45, ES = 0.14). A single bout of HIIE and MIE, performed 1 h before an HFM, can meaningfully attenuate IAUC-TAG in girls but not boys. Additionally, HIIE, but not MIE, may lower postprandial SBP in normotensive adolescents.

W' expenditure and reconstitution during severe intensity constant power exercise: mechanistic insight into the determinants of W'.

PubMed

Broxterman, Ryan M; Skiba, Phillip F; Craig, Jesse C; Wilcox, Samuel L; Ade, Carl J; Barstow, Thomas J

2016-10-01

The sustainable duration of severe intensity exercise is well-predicted by critical power (CP) and the curvature constant (W'). The development of the W'BAL model allows for the pattern of W' expenditure and reconstitution to be characterized and this model has been applied to intermittent exercise protocols. The purpose of this investigation was to assess the influence of relaxation phase duration and exercise intensity on W' reconstitution during dynamic constant power severe intensity exercise. Six men (24.6 ± 0.9 years, height: 173.5 ± 1.9 cm, body mass: 78.9 ± 5.6 kg) performed severe intensity dynamic handgrip exercise to task failure using 50% and 20% duty cycles. The W'BAL model was fit to each exercise test and the time constant for W' reconstitution (τW') was determined. The τW' was significantly longer for the 50% duty cycle (1640 ± 262 sec) than the 20% duty cycle (863 ± 84 sec, P = 0.02). Additionally, the relationship between τW' and CP was well described as an exponential decay (r(2) = 0.90, P < 0.0001). In conclusion, the W'BAL model is able to characterize the expenditure and reconstitution of W' across the contraction-relaxation cycles comprising severe intensity constant power handgrip exercise. Moreover, the reconstitution of W' during constant power severe intensity exercise is influenced by the relative exercise intensity, the duration of relaxation between contractions, and CP. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Caloric expenditure of aerobic, resistance, or combined high-intensity interval training using a hydraulic resistance system in healthy men.

PubMed

Falcone, Paul H; Tai, Chih-Yin; Carson, Laura R; Joy, Jordan M; Mosman, Matt M; McCann, Tyler R; Crona, Kevin P; Kim, Michael P; Moon, Jordan R

2015-03-01

Although exercise regimens vary in content and duration, few studies have compared the caloric expenditure of multiple exercise modalities with the same duration. The purpose of this study was to compare the energy expenditure of single sessions of resistance, aerobic, and combined exercise with the same duration. Nine recreationally active men (age: 25 ± 7 years; height: 181.6 ± 7.6 cm; weight: 86.6 ± 7.5 kg) performed the following 4 exercises for 30 minutes: a resistance training session using 75% of their 1-repetition maximum (1RM), an endurance cycling session at 70% maximum heart rate (HRmax), an endurance treadmill session at 70% HRmax, and a high-intensity interval training (HIIT) session on a hydraulic resistance system (HRS) that included repeating intervals of 20 seconds at maximum effort followed by 40 seconds of rest. Total caloric expenditure, substrate use, heart rate (HR), and rating of perceived exertion (RPE) were recorded. Caloric expenditure was significantly (p ≤ 0.05) greater when exercising with the HRS (12.62 ± 2.36 kcal·min), compared with when exercising with weights (8.83 ± 1.55 kcal·min), treadmill (9.48 ± 1.30 kcal·min), and cycling (9.23 ± 1.25 kcal·min). The average HR was significantly (p ≤ 0.05) greater with the HRS (156 ± 9 b·min), compared with that using weights (138 ± 16 b·min), treadmill (137 ± 5 b·min), and cycle (138 ± 6 b·min). Similarly, the average RPE was significantly (p ≤ 0.05) higher with the HRS (16 ± 2), compared with that using weights (13 ± 2), treadmill (10 ± 2), and cycle (11 ± 1). These data suggest that individuals can burn more calories performing an HIIT session with an HRS than spending the same amount of time performing a steady-state exercise session. This form of exercise intervention may be beneficial to individuals who want to gain the benefits of both resistance and cardiovascular training but have limited time to dedicate to exercise.

A method for monitoring intensity during aquatic resistance exercises.

PubMed

Colado, Juan C; Tella, Victor; Triplett, N Travis

2008-11-01

The aims of this study were (i) to check whether monitoring of both the rhythm of execution and the perceived effort is a valid tool for reproducing the same intensity of effort in different sets of the same aquatic resistance exercise (ARE) and (ii) to assess whether this method allows the ARE to be put at the same intensity level as its equivalent carried out on dry land. Four healthy trained young men performed horizontal shoulder abduction and adduction (HSAb/Ad) movements in water and on dry land. Muscle activation was recorded using surface electromyography of 1 stabilizer and several agonist muscles. Before the final tests, the ARE movement cadence was established individually following a rhythmic digitalized sequence of beats to define the alternate HSAb/Ad movements. This cadence allowed the subject to perform 15 repetitions at a perceived exertion of 9-10 using Hydro-Tone Bells. After that, each subject performed 2 nonconsecutive ARE sets. The dry land exercises (1 set of HSAb and 1 set of HSAd) were performed using a dual adjustable pulley cable motion machine, with the previous selection of weights that allowed the same movement cadence to be maintained and the completion of the same repetitions in each of the sets as with the ARE. The average normalized data were compared for the exercises in order to determine possible differences in muscle activity. The results show the validity of this method for reproducing the intensity of effort in different sets of the same ARE, but is not valid for matching the same intensity level as kinematically similar land-based exercises.

Satellite cell response to concurrent resistance exercise and high-intensity interval training in sedentary, overweight/obese, middle-aged individuals.

PubMed

Pugh, Jamie K; Faulkner, Steve H; Turner, Mark C; Nimmo, Myra A

2018-02-01

Sarcopenia can begin from the 4-5th decade of life and is exacerbated by obesity and inactivity. A combination of resistance exercise (RE) and endurance exercise is recommended to combat rising obesity and inactivity levels. However, work continues to elucidate whether interference in adaptive outcomes occur when RE and endurance exercise are performed concurrently. This study examined whether a single bout of concurrent RE and high-intensity interval training (HIIT) alters the satellite cell response following exercise compared to RE alone. Eight sedentary, overweight/obese, middle-aged individuals performed RE only (8 × 8 leg extensions at 70% 1RM), or RE + HIIT (10 × 1 min at 90% HR max on a cycle ergometer). Muscle biopsies were collected from the vastus lateralis before and 96 h after the RE component to determine muscle fiber type-specific total (Pax7 + cells) and active (MyoD + cells) satellite cell number using immunofluorescence microscopy. Type-I-specific Pax7 + (P = 0.001) cell number increased after both exercise trials. Type-I-specific MyoD + (P = 0.001) cell number increased after RE only. However, an elevated baseline value in RE + HIIT compared to RE (P = 0.046) was observed, with no differences between exercise trials at 96 h (P = 0.21). Type-II-specific Pax7 + and MyoD + cell number remained unchanged after both exercise trials (all P ≥ 0.13). Combining a HIIT session after a single bout of RE does not interfere with the increase in type-I-specific total, and possibly active, satellite cell number, compared to RE only. Concurrent RE + HIIT may offer a time-efficient way to maximise the physiological benefits from a single bout of exercise in sedentary, overweight/obese, middle-aged individuals.

Effects of a 4-Week Very Low-Carbohydrate Diet on High-Intensity Interval Training Responses

PubMed Central

Cipryan, Lukas; Plews, Daniel J.; Ferretti, Alessandro; Maffetone, Phil B.; Laursen, Paul B.

2018-01-01

The purpose of the study was to examine the effects of altering from habitual mixed Western-based (HD) to a very low-carbohydrate high-fat (VLCHF) diet over a 4-week timecourse on performance and physiological responses during high-intensity interval training (HIIT). Eighteen moderately trained males (age 23.8 ± 2.1 years) consuming their HD (48 ± 13% carbohydrate, 17 ± 3% protein, 35 ± 9% fat) were assigned to 2 groups. One group was asked to remain on their HD, while the other was asked to switch to a non-standardized VLCHF diet (8 ± 3% carbohydrate, 29 ± 15% protein, 63 ± 13% fat) for 4 weeks. Participants performed graded exercise tests (GXT) before and after the experiment, and an HIIT session (5x3min, work/rest 2:1, passive recovery, total time 34min) before, and after 2 and 4 weeks. Heart rate (HR), oxygen uptake (V̇O2), respiratory exchange ratio (RER), maximal fat oxidation rates (Fatmax) and blood lactate were measured. Total time to exhaustion (TTE) and maximal V̇O2 (V̇O2max) in the GXT increased in both groups, but between-group changes were trivial (ES ± 90% CI: -0.1 ± 0.3) and small (0.57 ± 0.5), respectively. Between-group difference in Fatmax change (VLCHF: 0.8 ± 0.3 to 1.1 ± 0.2 g/min; HD: 0.7 ± 0.2 to 0.8 ± 0.2 g/min) was large (1.2±0.9), revealing greater increases in the VLCHF versus HD group. Between-group comparisons of mean changes in V̇O2 and HR during the HIIT sessions were trivial to small, whereas mean RER decreased more in the VLCHF group (-1.5 ± 0.1). Lactate changes between groups were unclear. Adoption of a VLCHF diet over 4 weeks increased Fatmax and did not adversely affect TTE during the GXT or cardiorespiratory responses to HIIT compared with the HD. Key points A group of participants that changed from habitual mixed western-based to VLCHF diet over 4 weeks substantially increased rates of fat oxidation shown during a graded exercise test and high-intensity interval training (HIIT) session. Performance and cardiorespiratory responses during a graded exercise test and HIIT were not impaired after consuming a VLCHF diet relative to a group consuming their mixed western-based diet. A four-week adaptation period to a VLCHF diet preserved high-intensity exercise performance. PMID:29769827

Influence of exercise intensity on skeletal muscle blood flow, O2 extraction and O2 uptake on-kinetics

PubMed Central

Jones, Andrew M; Krustrup, Peter; Wilkerson, Daryl P; Berger, Nicolas J; Calbet, José A; Bangsbo, Jens

2012-01-01

Following the start of low-intensity exercise in healthy humans, it has been established that the kinetics of skeletal muscle O2 delivery is faster than, and does not limit, the kinetics of muscle O2 uptake (). Direct data are lacking, however, on the question of whether O2 delivery might limit kinetics during high-intensity exercise. Using multiple exercise transitions to enhance confidence in parameter estimation, we therefore investigated the kinetics of, and inter-relationships between, muscle blood flow (), a– difference and following the onset of low-intensity (LI) and high-intensity (HI) exercise. Seven healthy males completed four 6 min bouts of LI and four 6 min bouts of HI single-legged knee-extension exercise. Blood was frequently drawn from the femoral artery and vein during exercise and , a– difference and were calculated and subsequently modelled using non-linear regression techniques. For LI, the fundamental component mean response time (MRTp) for kinetics was significantly shorter than kinetics (mean ± SEM, 18 ± 4 vs. 30 ± 4 s; P < 0.05), whereas for HI, the MRTp for and was not significantly different (27 ± 5 vs. 29 ± 4 s, respectively). There was no difference in the MRTp for either or between the two exercise intensities; however, the MRTp for a– difference was significantly shorter for HI compared with LI (17 ± 3 vs. 28 ± 4 s; P < 0.05). Excess O2, i.e. oxygen not taken up (×), was significantly elevated within the first 5 s of exercise and remained unaltered thereafter, with no differences between LI and HI. These results indicate that bulk O2 delivery does not limit kinetics following the onset of LI or HI knee-extension exercise. PMID:22711961

Carbohydrate feeding during recovery alters the skeletal muscle metabolic response to repeated sessions of high-intensity interval exercise in humans.

PubMed

Cochran, Andrew J R; Little, Jonathan P; Tarnopolsky, Mark A; Gibala, Martin J

2010-03-01

Exercise training under conditions of reduced carbohydrate (CHO) availability has been reported to augment gains in skeletal muscle oxidative capacity; however, the underlying mechanisms are unclear. We examined the effect of manipulating CHO intake on the acute metabolic response to high-intensity interval exercise, including signaling cascades linked to mitochondrial biogenesis. Ten men performed two trials in random order separated by >or=1 wk. Each trial consisted of a morning (AM) and afternoon (PM) training session (5 x 4 min cycling at approximately 90-95% of heart rate reserve) separated by 3 h of recovery during which subjects ingested a high-CHO drink (HI-HI) or nonenergetic placebo (HI-LO) before PM exercise. Biopsies (vastus lateralis) revealed that muscle phosphocreatine and ATP content were similar after AM exercise but decreased to a greater extent during PM exercise in HI-LO vs. HI-HI. Phosphorylation of p38 mitogen-activated protein kinase (MAPK) and AMP-activated protein kinase (AMPK) increased approximately 4-fold and 2-fold, respectively, during AM exercise with no difference between conditions. After PM exercise, p38 MAPK phosphorylation was higher in HI-LO vs. HI-HI, whereas AMPK was not different between conditions. Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1 alpha) gene expression increased approximately 8-fold during recovery from AM exercise and remained elevated during PM exercise with no differences between conditions. Cytochrome oxidase subunit 4 (COXIV) mRNA was also elevated 3 h after AM exercise, with no difference between conditions. These data provide evidence that p38 MAPK is a nutrient-sensitive signaling molecule that could be involved in the altered skeletal muscle adaptive response reported after exercise training under conditions of restricted CHO intake, but further research is required to confirm this hypothesis.

Perspectives on high-intensity interval exercise for health promotion in children and adolescents

PubMed Central

Bond, Bert; Weston, Kathryn L; Williams, Craig A; Barker, Alan R

2017-01-01

Physical activity lowers future cardiovascular disease (CVD) risk; however, few children and adolescents achieve the recommended minimum amount of daily activity. Accordingly, there is virtue in identifying the efficacy of small volumes of high-intensity exercise for health benefits in children and adolescents for the primary prevention of CVD risk. The purpose of this narrative review is to provide a novel overview of the available literature concerning high-intensity interval-exercise (HIIE) interventions in children and adolescents. Specifically, the following areas are addressed: 1) outlining the health benefits observed following a single bout of HIIE, 2) reviewing the role of HIIE training in the management of pediatric obesity, and 3) discussing the effectiveness of school-based HIIE training. In total, 39 HIIE intervention studies were included in this review. Based upon the available data, a single bout of high-intensity exercise provides a potent stimulus for favorable, acute changes across a range of cardiometabolic outcomes that are often superior to a comparative bout of moderate-intensity exercise (14 studies reviewed). HIIE also promotes improvements in cardiorespiratory fitness and cardiometabolic health status in overweight and obese children and adolescents (10 studies reviewed) and when delivered in the school setting (15 studies reviewed). We thus conclude that high-intensity exercise is a feasible and potent method of improving a range of cardiometabolic outcomes in children and adolescents. However, further work is needed to optimize the delivery of HIIE interventions in terms of participant enjoyment and acceptability, to include a wider range of health outcomes, and to control for important confounding variables (eg, changes in diet and habitual physical activity). Finally, research into the application of HIIE training interventions to children and adolescents of different ages, sexes, pubertal status, and sociocultural backgrounds is required. PMID:29225481

The effect of the menstrual cycle and water consumption on physiological responses during prolonged exercise at moderate intensity in hot conditions.

PubMed

Hashimoto, Hideki; Ishijima, Toshimichi; Suzuki, Katsuhiko; Higuchi, Mitsuru

2016-09-01

Reproductive hormones are likely to be involved in thermoregulation through body fluid dynamics. In the present study, we aimed to investigate the effect of the menstrual cycle and water consumption on physiological responses to prolonged exercise at moderate intensity in hot conditions. Eight healthy young women with regular menstrual cycles performed cycling exercise for 90 minutes at 50% V̇O2peak intensity during the low progesterone (LP) level phase and high progesterone (HP) level phase, with or without water consumption, under hot conditions (30°C, 50% relative humidity). For the water consumption trials, subjects ingested water equivalent to the loss in body weight that occurred in the earlier non-consumption trial. For all four trials, rectal temperature, cardiorespiratory responses, and ratings of perceived exertion (RPE) were measured. Throughout the 90-minute exercise period, rectal temperatures during HP were higher than during LP by an average of 0.4 °C in the non-consumption trial (P<0.01) and 0.2 °C in the water consumption trial (P<0.05). During exercise, water consumption affected the changes in rectal temperature and heat rate (HR) during HP, but it did not exert these effects during LP. Furthermore, we found a negative correlation between estradiol levels and rectal temperature during LP. During prolonged exercise at moderate intensity under hot conditions, water consumption is likely to be useful for suppressing the associated increase in body temperature and HR, particularly during HP, whereas estradiol appears to be useful for suppressing the increase in rectal temperature during LP.

Myocellular limitations of human performance and their modification through genome-dependent responses at altitude.

PubMed

Flueck, Martin

2010-03-01

Human muscle operates along a continuum of power output, which is set through bioenergetic and anatomical principles. In turn, environmental and intrinsic factors during contractile work exert pronounced control over muscle performance by instructing muscle remodelling. This phenotypic control is specifically indicated with intense exercise at altitude, when extra strain is put on energy supply and the temperature-dependent mechanical efficiency of contraction. While it is classically thought that chronic exposure to hypoxia is maladaptive, repeated short episodes of reduced oxygenation alone or in combination with intense endurance work is now understood to preserve exercise performance when atmospheric oxygen levels are low. Endurance training at moderate altitude exploits the temperature-dependent malleability of energy supply that may maximize metabolic flux at altitude. The contribution of genomic mechanisms is important to the plasticity of metabolic pathways in exercised muscle. This is highlighted by the association of distinct gene polymorphisms in master governors of mitochondrial and vascular growth with exercise phenotypes. Feedforward control of human locomoter muscle by exercise involves the transient upregulation of transcript expression for metabolic processes. The response of the mitochondrial transcriptome to intense exercise is graded with respect to mitochondrial content and deoxygenation during muscle work and reflects exercise-induced mitochondrial biogenesis. This supports the notion that genome-mediated muscle malleability is under feedback control by design constraints of the pathway of oxygen. Thus, activity-dependent and genetic mechanisms contribute to the interindividual difference in the metabolic bottlenecks in athletes performing in exceptional environmental conditions.

Effects of negative air ions on oxygen uptake kinetics, recovery and performance in exercise: a randomized, double-blinded study

NASA Astrophysics Data System (ADS)

Nimmerichter, Alfred; Holdhaus, Johann; Mehnen, Lars; Vidotto, Claudia; Loidl, Markus; Barker, Alan R.

2014-09-01

Limited research has suggested that acute exposure to negatively charged ions may enhance cardio-respiratory function, aerobic metabolism and recovery following exercise. To test the physiological effects of negatively charged air ions, 14 trained males (age: 32 ± 7 years; : 57 ± 7 mL min-1 kg-1) were exposed for 20 min to either a high-concentration of air ions (ION: 220 ± 30 × 103 ions cm-3) or normal room conditions (PLA: 0.1 ± 0.06 × 103 ions cm-3) in an ionization chamber in a double-blinded, randomized order, prior to performing: (1) a bout of severe-intensity cycling exercise for determining the time constant of the phase II response ( τ) and the magnitude of the slow component (SC); and (2) a 30-s Wingate test that was preceded by three 30-s Wingate tests to measure plasma [adrenaline] (ADR), [nor-adrenaline] (N-ADR) and blood [lactate] (BLac) over 20 min during recovery in the ionization chamber. There was no difference between ION and PLA for the phase II τ (32 ± 14 s vs. 32 ± 14 s; P = 0.7) or SC (404 ± 214 mL vs 482 ± 217 mL; P = 0.17). No differences between ION and PLA were observed at any time-point for ADR, N-ADR and BLac as well as on peak and mean power output during the Wingate tests (all P > 0.05). A high-concentration of negatively charged air ions had no effect on aerobic metabolism during severe-intensity exercise or on performance or the recovery of the adrenergic and metabolic responses after repeated-sprint exercise in trained athletes.

One year of high-intensity interval training improves exercise capacity, but not left ventricular function in stable heart transplant recipients: a randomised controlled trial.

PubMed

Rustad, Lene A; Nytrøen, Kari; Amundsen, Brage H; Gullestad, Lars; Aakhus, Svend

2014-02-01

Heart transplant recipients have lower exercise capacity and impaired cardiac function compared with the normal population. High-intensity interval training (HIIT) improves exercise capacity and cardiac function in patients with heart failure and hypertension, but the effect on cardiac function in stable heart transplant recipients is not known. Thus, we investigated whether HIIT improved cardiac function and exercise capacity in stable heart transplant recipients by use of comprehensive rest- and exercise-echocardiography and cardiopulmonary exercise testing. Fifty-two clinically stable heart transplant recipients were randomised either to HIIT (4 × 4 minutes at 85-95% of peak heart rate three times per week for eight weeks) or to control. Three such eight-week periods were distributed throughout one year. Echocardiography (rest and submaximal exercise) and cardiopulmonary exercise testing were performed at baseline and follow-up. One year of HIIT increased VO 2peak from 27.7 ± 5.5 at baseline to 30.9 ± 5.0 ml/kg/min at follow-up, while the control group remained unchanged (28.5 ± 7.0 vs. 28.0 ± 6.7 ml/kg per min, p < 0.001 for difference between the groups). Systolic and diastolic left ventricular functions at rest and during exercise were generally unchanged by HIIT. Whereas HIIT is feasible in heart transplant recipients and effectively improves exercise capacity, it does not alter cardiac systolic and diastolic function significantly. Thus, the observed augmentation in exercise capacity is best explained by extra-cardiac adaptive mechanisms.

Comparison of high-intensity vs. high-volume resistance training on the BDNF response to exercise.

PubMed

Church, David D; Hoffman, Jay R; Mangine, Gerald T; Jajtner, Adam R; Townsend, Jeremy R; Beyer, Kyle S; Wang, Ran; La Monica, Michael B; Fukuda, David H; Stout, Jeffrey R

2016-07-01

This study compared the acute and chronic response of circulating plasma brain-derived neurotrophic factor (BDNF) to high-intensity low-volume (HI) and low-intensity high volume (HV) resistance training. Twenty experienced resistance-trained men (23.5 ± 2.6 y, 1.79 ± 0.05 m, 75.7 ± 13.8 kg) volunteered for this study. Before the resistance training program (PRE), participants performed an acute bout of exercise using either the HI [3-5 reps; 90% of one repetition maximum (1RM)] or HV (10-12 reps; 70% 1RM) training paradigm. The acute exercise protocol was repeated after 7 wk of training (POST). Blood samples were obtained at rest (BL), immediately (IP), 30 min (30P), and 60 min (60P) post exercise at PRE and POST. A three-way repeated measure ANOVA was used to analyze acute changes in BDNF concentrations during HI and HV resistance exercise and the effect of 7 wk of training. No training × time × group interaction in BDNF was noted (P = 0.994). Significant main effects for training (P = 0.050) and time (P < 0.001) in BDNF were observed. Significant elevations in BDNF concentrations were seen from BL at IP (P = 0.001), 30P (P < 0.001), and 60P (P < 0.001) in both HI and HV combined during PRE and POST. BDNF concentrations were also observed to increase from PRE to POST when collapsed across groups and time. No significant group × training interaction (P = 0.342), training (P = 0.105), or group (P = 0.238) effect were noted in the BDNF area under the curve response. Results indicate that BDNF concentrations are increased after an acute bout of resistance exercise, regardless of training paradigm, and are further increased during a 7-wk training program in experienced lifters. Copyright © 2016 the American Physiological Society.

High-intensity compared to moderate-intensity training for exercise initiation, enjoyment, adherence, and intentions: an intervention study.

PubMed

Heinrich, Katie M; Patel, Pratik M; O'Neal, Joshua L; Heinrich, Bryan S

2014-08-03

Understanding exercise participation for overweight and obese adults is critical for preventing comorbid conditions. Group-based high-intensity functional training (HIFT) provides time-efficient aerobic and resistance exercise at self-selected intensity levels which can increase adherence; behavioral responses to HIFT are unknown. This study examined effects of HIFT as compared to moderate-intensity aerobic and resistance training (ART) on exercise initiation, enjoyment, adherence, and intentions. A stratified, randomized two-group pre-test posttest intervention was conducted for eight weeks in 2012 with analysis in 2013. Participants (n = 23) were stratified by median age (< or ≥ 28) and body mass index (BMI; < or ≥ 30.5). Participants were physically inactive with an average BMI of 31.1 ± 3.5 kg/m2, body fat percentage of 42.0 ± 7.4%, weight of 89.5 ± 14.2 kg, and ages 26.8 ± 5.9 years. Most participants were white, college educated, female, and married/engaged. Both groups completed 3 training sessions per week. The ART group completed 50 minutes of moderate aerobic exercise each session and full-body resistance training on two sessions per week. The HIFT group completed 60-minute sessions of CrossFit™ with actual workouts ranging from 5-30 minutes. Participants completed baseline and posttest questionnaires indicating reasons for exercise initiation (baseline), exercise enjoyment, and exercise intentions (posttest). Adherence was defined as completing 90% of exercise sessions. Daily workout times were recorded. Participants provided mostly intrinsic reasons for exercise initiation. Eighteen participants adhered (ART = 9, 81.8%; HIFT = 9, 75%). HIFT dropouts (p = .012) and ART participants (p = .009) reported lower baseline exercise enjoyment than HIFT participants, although ART participants improved enjoyment at posttest (p = .005). More HIFT participants planned to continue the same exercise than ART participants (p = .002). No significant changes in BMI or body composition were found. Workouts were shorter for HIFT than ART (p < .001). HIFT participants spent significantly less time exercising per week, yet were able to maintain exercise enjoyment and were more likely to intend to continue. High-intensity exercise options should be included in public health interventions. ClinicalTrials.gov Identifier: http://NCT02185872. Registered 9 July 2014.

A randomized comparison study regarding the impact of short-duration, high-intensity exercise and traditional exercise on anthropometric and body composition measurement changes in post-menopausal women--A pilot study.

PubMed

Grossman, Joan A Cebrick; Payne, Ellen K

2016-03-01

The mode and duration of exercise necessary to change body composition and reduce weight remains debatable. Menopause results in hormonal changes that preclude weight loss. This randomized pilot study compared the effects of short-duration, high-intensity interval training and traditional exercise on anthropometric and body composition measurement changes in post-menopausal women. To compare the effects of short-duration, high-intensity interval training and traditional methods of exercise (walking) on anthropometric, body composition and body weight change over a 12-week period. Subjects (N = 18) were post-menopausal, sedentary female volunteers, randomly assigned into one of two exercise groups. Both groups exercised five out of seven days for 12 weeks. The resistance group (n = 8) (54.3 ± 7.3 years; BMI = 28.0 ± 2.1 kg/m(2); mean ± SD) exercised for 15.0 ± 3.5 min, which consisted of five different exercise routines including upper and lower extremity, a cardio segment, yoga and abdominal exercises. The walkers (n = 10) (56.6 ± 5.2 years; BMI = 29.2 ± 2.6 kg/m(2); mean ± SD) exercised for 40.0 ± 5.0 min at 65% of their age-predicted maximum heart rate. Relative (%) body fat was measured via DEXA scan, along with five anthropometric measurements, all of which were taken prior to and after 12 weeks. Independent sample t-tests were probed for differences, p ≤ 0.05. No statistically significant changes were determined between the groups for pre-and post-measurements. The outcomes of this study provide a foundation for future comparisons of short-duration high-intensity interval training exercise and traditional exercise, or walking, on anthropometric and body composition measurement changes in sedentary, overweight, post-menopausal females over a 12-week period. © The Author(s) 2016.

Exercise and end-stage kidney disease: functional exercise capacity and cardiovascular outcomes.

PubMed

Parsons, Trisha L; King-Vanvlack, Cheryl E

2009-11-01

This review examined published reports of the impact of extradialytic and intradialytic exercise programs on physiologic aerobic exercise capacity, functional exercise endurance, and cardiovascular outcomes in individuals with ESKD. Studies spanning 30 years from the first published report of exercise in the ESKD population were reviewed. Studies conducted in the first half of the publication record focused on the efficacy of exercise training programs performed "off"-dialysis with respect to the modification of traditional cardiovascular risk factors, aerobic capacity, and its underlying determinants. In the latter half of the record, there had been a shift to include other client-centered goals such as physical function and quality of life. There is evidence that both intra- and extradialytic programs can significantly enhance aerobic exercise capacity, but moderate-intensity extradialytic programs may result in greater gains in those individuals who initially have extremely poor aerobic capacity. Functionally, substantive improvements in exercise endurance in excess of the minimum clinical significant difference can occur following either low- or moderate-intensity exercise regardless of the initial level of performance. Reductions in blood pressure and enhanced vascular functioning reported after predominantly intradialytic exercise programs suggest that either low- or moderate-intensity exercise programs can confer cardiovascular benefit. Regardless of prescription model, there was an overall lack of evidence regarding the impact of exercise-induced changes in exercise capacity, endurance, and cardiovascular function on a number of relevant health outcomes (survival, morbidity, and cardiovascular risk), and, more importantly, there is no evidence on the long-term impact of exercise and/or physical activity interventions on these health outcomes.

Statistical Learning Is Not Affected by a Prior Bout of Physical Exercise.

PubMed

Stevens, David J; Arciuli, Joanne; Anderson, David I

2016-05-01

This study examined the effect of a prior bout of exercise on implicit cognition. Specifically, we examined whether a prior bout of moderate intensity exercise affected performance on a statistical learning task in healthy adults. A total of 42 participants were allocated to one of three conditions-a control group, a group that exercised for 15 min prior to the statistical learning task, and a group that exercised for 30 min prior to the statistical learning task. The participants in the exercise groups cycled at 60% of their respective V˙O2 max. Each group demonstrated significant statistical learning, with similar levels of learning among the three groups. Contrary to previous research that has shown that a prior bout of exercise can affect performance on explicit cognitive tasks, the results of the current study suggest that the physiological stress induced by moderate-intensity exercise does not affect implicit cognition as measured by statistical learning. Copyright © 2015 Cognitive Science Society, Inc.

Physiological adaptations to low-volume, high-intensity interval training in health and disease.

PubMed

Gibala, Martin J; Little, Jonathan P; Macdonald, Maureen J; Hawley, John A

2012-03-01

Exercise training is a clinically proven, cost-effective, primary intervention that delays and in many cases prevents the health burdens associated with many chronic diseases. However, the precise type and dose of exercise needed to accrue health benefits is a contentious issue with no clear consensus recommendations for the prevention of inactivity-related disorders and chronic diseases. A growing body of evidence demonstrates that high-intensity interval training (HIT) can serve as an effective alternate to traditional endurance-based training, inducing similar or even superior physiological adaptations in healthy individuals and diseased populations, at least when compared on a matched-work basis. While less well studied, low-volume HIT can also stimulate physiological remodelling comparable to moderate-intensity continuous training despite a substantially lower time commitment and reduced total exercise volume. Such findings are important given that 'lack of time' remains the most commonly cited barrier to regular exercise participation. Here we review some of the mechanisms responsible for improved skeletal muscle metabolic control and changes in cardiovascular function in response to low-volume HIT. We also consider the limited evidence regarding the potential application of HIT to people with, or at risk for, cardiometabolic disorders including type 2 diabetes. Finally, we provide insight on the utility of low-volume HIT for improving performance in athletes and highlight suggestions for future research.

Exercise training dose differentially alters muscle and heart capillary density and metabolic functions in an obese rat with metabolic syndrome.

PubMed

Machado, Marcus Vinicius; Vieira, Aline Bomfim; da Conceição, Fabiana Gomes; Nascimento, Alessandro Rodrigues; da Nóbrega, Antonio Claudio Lucas; Tibirica, Eduardo

2017-12-01

What is the central question of this study? Regular exercise is recommended as a non-pharmacological approach for the prevention and treatment of metabolic syndrome. However, the impact of different combinations of intensity, duration and frequency of exercise on metabolic syndrome and microvascular density has not been reported. What is the main finding and its importance? We provide evidence on the impact of aerobic exercise dose on metabolic and microvascular alterations in an experimental model of metabolic syndrome induced by high-fat diet. We found that the exercise frequency and duration were the main factors affecting anthropometric and metabolic parameters and microvascular density in the skeletal muscle. Exercise intensity was related only to microvascular density in the heart. We evaluated the effect of the frequency, duration and intensity of exercise training on metabolic parameters and structural capillary density in obese rats with metabolic syndrome. Wistar-Kyoto rats were fed either a standard commercial diet (CON) or a high-fat diet (HFD). Animals that received the HFD were randomly separated into either a sedentary (SED) group or eight different exercise groups that varied according to the frequency, duration and intensity of training. After 12 weeks of aerobic exercise training, the body composition, aerobic capacity, haemodynamic variables, metabolic parameters and capillary density in the heart and skeletal muscle were evaluated. All the exercise training groups showed reduced resting systolic blood pressure and heart rate and normalized fasting glucose. The minimal amount of exercise (90 min per week) produced little effect on metabolic syndrome parameters. A moderate amount of exercise (150 min per week) was required to reduce body weight and improve capillary density. However, only the high amount of exercise (300 min per week) significantly reduced the amount of body fat depots. The three-way ANOVA showed a main effect of exercise frequency and duration for the improvement of metabolic syndrome and capillary density in skeletal muscle. Exercise intensity was a main factor in reversing microvascular rarefaction in the heart. © 2017 The Authors. Experimental Physiology © 2017 The Physiological Society.

Leisure time physical activity patterns in Odisha, India.

PubMed

Ganesh, G Shankar; Patel, Rishee; Dwivedi, Vikram; Chhabra, Deepak; Balakishore, P; Dakshinamoorthy, Anandhi; Kaur, Parminder

2018-05-01

The World Health Organization has recommended a moderate intensity physical activity of 150min, or 75min vigorous-intensity physical activity per week to achieve optimal health benefits. It is not known if Indian populations who indulge in leisure time physical exercises satisfy these recommendations. This study used a questionnaire to obtain data regarding demographic details, current engagement in leisure time physical activities, and dosages of these exercises from participants between 18 and 64 years of age. Data was collected from a total of 390 participants (231 males and 159 females). 50.76% and 34.35% of the participants reported exercising voluntarily and for health benefits respectively. Most participants (94.61%) indicated exercising without prescription. 55.38% and 12.82% of the participants under and above 38 years of age perform moderate to vigorous intensity exercises respectively. The over-all results of this study indicate that the participants' choices of leisure time physical exercises are based on their personal choices and beliefs. The exercise intensities undertaken do not meet the global recommended intensities, especially in those above 38 years of age. Professionals and facilities to engage the public in the WHO recommended intensities of physical activity needs to be established. Copyright © 2017 Diabetes India. Published by Elsevier Ltd. All rights reserved.

Cellular Stress Response Gene Expression During Upper and Lower Body High Intensity Exercises

PubMed Central

Kochanowicz, Andrzej; Sawczyn, Stanisław; Niespodziński, Bartłomiej; Mieszkowski, Jan; Kochanowicz, Kazimierz

2017-01-01

Objectives The aim was to compare the effect of upper and lower body high-intensity exercise on chosen genes expression in athletes and non-athletes. Method Fourteen elite male artistic gymnasts (EAG) aged 20.6 ± 3.3 years and 14 physically active men (PAM) aged 19.9 ± 1.0 years performed lower and upper body 30 s Wingate Tests. Blood samples were collected before, 5 and 30 minutes after each effort to assess gene expression via PCR. Results Significantly higher mechanical parameters after lower body exercise was observed in both groups, for relative power (8.7 ± 1.2 W/kg in gymnasts, 7.2 ± 1.2 W/kg in controls, p = 0.01) and mean power (6.7 ± 0.7 W/kg in gymnasts, 5.4 ± 0.8 W/kg in controls, p = 0.01). No differences in lower versus upper body gene expression were detected for all tested genes as well as between gymnasts and physical active man. For IL-6 m-RNA time-dependent effect was observed. Conclusions Because of no significant differences in expression of genes associated with cellular stress response the similar adaptive effect to exercise may be obtained so by lower and upper body exercise. PMID:28141870

Virtual and live social facilitation while exergaming: competitiveness moderates exercise intensity.

PubMed

Snyder, Amanda L; Anderson-Hanley, Cay; Arciero, Paul J

2012-04-01

Grounded in social facilitation theory, this study compared the impact on exercise intensity of a virtual versus a live competitor, when riding a virtual reality-enhanced stationary bike ("cybercycle"). It was hypothesized that competitiveness would moderate effects. Twenty-three female college students were exposed to three conditions on a cybercycle: solo training, virtual competitor, and live competitor. After training without a competitor (solo condition for familiarization with equipment), participants competed against a virtual avatar or live rider (random order of presentation). A repeated-measures analysis revealed a significant condition (virtual/live) by competitiveness (high/low) interaction for exercise intensity (watts). More competitive participants exhibited significantly greater exercise intensity when competing against a live versus virtual competitor. The implication is that live competitors can have an added social facilitation effect and influence exercise intensity, although competitiveness moderates this effect.

Acute Response of Circulating Vascular Regulating MicroRNAs during and after High-Intensity and High-Volume Cycling in Children.

PubMed

Kilian, Yvonne; Wehmeier, Udo F; Wahl, Patrick; Mester, Joachim; Hilberg, Thomas; Sperlich, Billy

2016-01-01

The aim of the present study was to analyze the response of vascular circulating microRNAs (miRNAs; miR-16, miR-21, miR-126) and the VEGF mRNA following an acute bout of HIIT and HVT in children. Twelve healthy competitive young male cyclists (14.4 ± 0.8 years; 57.9 ± 9.4 ml·min(-1)·kg(-1) peak oxygen uptake) performed one session of high intensity 4 × 4 min intervals (HIIT) at 90-95% peak power output (PPO), each interval separated by 3 min of active recovery, and one high volume session (HVT) consisting of a constant load exercise for 90 min at 60% PPO. Capillary blood from the earlobe was collected under resting conditions, during exercise (d1 = 20 min, d2 = 30 min, d3 = 60 min), and 0, 30, 60, 180 min after the exercise to determine miR-16, -21, -126, and VEGF mRNA. HVT significantly increased miR-16 and miR-126 during and after the exercise compared to pre-values, whereas HIIT showed no significant influence on the miRNAs compared to pre-values. VEGF mRNA significantly increased during and after HIIT (d1, 30', 60', 180') and HVT (d3, 0', 60'). RESULTS of the present investigation suggest a volume dependent exercise regulation of vascular regulating miRNAs (miR-16, miR-21, miR-126) in children. In line with previous data, our data show that acute exercise can alter circulating miRNAs profiles that might be used as novel biomarkers to monitor acute and chronic changes due to exercise in various tissues.

Impact of high- and low-intensity targeted exercise training on the type of substrate utilization in obese boys submitted to a hypocaloric diet.

PubMed

Brandou, F; Savy-Pacaux, A M; Marie, J; Bauloz, M; Maret-Fleuret, I; Borrocoso, S; Mercier, J; Brun, J F

2005-09-01

We assessed the effect of two programs combining a hypocaloric diet with low-intensity (LI) or high-intensity (HI) exercise training, during two months, on substrate utilization at exercise in obese children. Fifteen obese boys participated in a combined program of exercise and caloric restriction-induced weight loss (diet starting two weeks before the training program). The maximal fat oxidation point (Lipox max) was determined to individualize exercise training. Training consisted of cycling at either LI (Lipox max) for seven children or HI (Lipoxmax+40% Lipox max) for eight children. All children exhibited a decrease in weight (LI: -5.2 kg +/- 0.7 (P<0.01), HI: -7 kg +/- 0.7 (P<0.01)). While in the LI group, both fat and CHO oxidation were unchanged after training, HI group oxidize less fat and more CHO after training when exercising at 20% and 30% Wmax th (P = 0.02). While a LI exercise training program maintains (but does not improve) the ability to oxidize fat at exercise, HI training actually shifts towards CHO the balance of substrate oxidation during exercise. Thus, a low intensity training protocol seems to counteract to some extent the decline in lipid oxidation at exercise that occurs after a hypocaloric diet, and is thus likely to be synergistic to diet in the weight lowering strategy.

Components of Fatigue: Mind and Body.

PubMed

Carriker, Colin R

2017-11-01

Carriker, CR. Components of fatigue: mind and body. J Strength Cond Res 31(11): 3170-3176, 2017-Maximal intensity exercise requires significant energy demand. Subsequently, prolonged high-intensity effort eventually initiates volitional cessation of the event; often preceeded by a sensation of fatigue. Those examining the basis of fatigue tend to advocate either a peripheral or central model to explain such volitional failure. Practitioners and athletes who understand the tenants of fatigue can tailor their exercise regimens to target areas of potential physical or mental limitation. This review examines the rationale surrounding 2 separate models which postulate the origination of fatigue. Although the peripheral model suggests that fatigue occurs at the muscles, others have suggested a teloanticipatory cognitive component which plays a dominant role. Those familiar with both models may better integrate practice-based evidence into evidence-based practice. The highly individual nature of human performance further highlights the compulsion to comprehend the spectrum of fatigue, such that the identification of insufficiencies should mandate the development of a training purview for peak human performance.