Resistance exercise training and the orthostatic response

NASA Technical Reports Server (NTRS)

McCarthy, J. P.; Bamman, M. M.; Yelle, J. M.; LeBlanc, A. D.; Rowe, R. M.; Greenisen, M. C.; Lee, S. M.; Spector, E. R.; Fortney, S. M.

1997-01-01

Resistance exercise has been suggested to increase blood volume, increase the sensitivity of the carotid baroreceptor cardiac reflex response (BARO), and decrease leg compliance, all factors that are expected to improve orthostatic tolerance. To further test these hypotheses, cardiovascular responses to standing and to pre-syncopal limited lower body negative pressure (LBNP) were measured in two groups of sedentary men before and after a 12-week period of either exercise (n = 10) or no exercise (control, n = 9). Resistance exercise training consisted of nine isotonic exercises, four sets of each, 3 days per week, stressing all major muscle groups. After exercise training, leg muscle volumes increased (P < 0.05) by 4-14%, lean body mass increased (P = 0.00) by 2.0 (0.5) kg, leg compliance and BARO were not significantly altered, and the maximal LBNP tolerated without pre-syncope was not significantly different. Supine resting heart rate was reduced (P = 0.03) without attenuating the heart rate or blood pressure responses during the stand test or LBNP. Also, blood volume (125I and 51Cr) and red cell mass were increased (P < 0.02) by 2.8% and 3.9%, respectively. These findings indicate that intense resistance exercise increases blood volume but does not consistently improve orthostatic tolerance.

Intake of branched-chain amino acids influences the levels of MAFbx mRNA and MuRF-1 total protein in resting and exercising human muscle.

PubMed

Borgenvik, Marcus; Apró, William; Blomstrand, Eva

2012-03-01

Resistance exercise and amino acids are two major factors that influence muscle protein turnover. Here, we examined the effects of resistance exercise and branched-chain amino acids (BCAA), individually and in combination, on the expression of anabolic and catabolic genes in human skeletal muscle. Seven subjects performed two sessions of unilateral leg press exercise with randomized supplementation with BCAA or flavored water. Biopsies were collected from the vastus lateralis muscle of both the resting and exercising legs before and repeatedly after exercise to determine levels of mRNA, protein phosphorylation, and amino acid concentrations. Intake of BCAA reduced (P < 0.05) MAFbx mRNA by 30 and 50% in the resting and exercising legs, respectively. The level of MuRF-1 mRNA was elevated (P < 0.05) in the exercising leg two- and threefold under the placebo and BCAA conditions, respectively, whereas MuRF-1 total protein increased by 20% (P < 0.05) only in the placebo condition. Phosphorylation of p70(S6k) increased to a larger extent (∼2-fold; P < 0.05) in the early recovery period with BCAA supplementation, whereas the expression of genes regulating mTOR activity was not influenced by BCAA. Muscle levels of phenylalanine and tyrosine were reduced (13-17%) throughout recovery (P < 0.05) in the placebo condition and to a greater extent (32-43%; P < 0.05) following BCAA supplementation in both resting and exercising muscle. In conclusion, BCAA ingestion reduced MAFbx mRNA and prevented the exercise-induced increase in MuRF-1 total protein in both resting and exercising leg. Further-more, resistance exercise differently influenced MAFbx and MuRF-1 mRNA expression, suggesting both common and divergent regulation of these two ubiquitin ligases.

Exercise capacity in young adults with hypertension and systolic blood pressure difference between right arm and leg after repair of coarctation of the aorta.

PubMed

Instebø, Arne; Norgård, Gunnar; Helgheim, Vegard; Røksund, Ola Drange; Segadal, Leidulf; Greve, Gottfried

2004-10-01

Coarctation of the aorta represents 5-7% of congenital heart defects. Symptoms and prognosis depend on the degree of stenosis, age at surgery, surgical method and the presence of other heart defects. Postoperative complications are hypertension, restenosis and an abnormal blood pressure response during exercise. This study includes 41 patients, 15-40 years old, operated in the period 1975-1996. All were exercised on a treadmill until maximal oxygen consumption was achieved. Blood pressure was measured in the right arm and leg before and immediately after exercise, and in the right arm during exercise. Oxygen consumption was monitored and we defined an aerobic phase, an isocapnic buffering phase and a hypocapnic hyperventilation phase. The resting systolic blood pressure correlates with the resting systolic blood pressure difference between right arm and leg. A resting systolic blood pressure difference between the right arm and leg of 0.13 kPa (1 mmHg) to 2.67 kPa (20 mmHg) corresponds with a slight increase in resting systolic blood pressure. This rise in blood pressure increases the aerobic phase of the exercise test, helping the patients to achieve higher maximal oxygen consumption. A resting systolic blood pressure difference of more than 2.67 kPa (20 mmHg) corresponds with severe hypertension and causes reduction in the aerobic phase and maximal oxygen consumption. Resting systolic blood pressure and resting systolic blood pressure difference between the right arm and leg are not indicators for blood pressure response during exercise. Exercise testing is important to reveal exercise-induced hypertension and to monitor changes in transition from aerobic to anaerobic exercise and limitation to exercise capacity.

Sympathetic adaptations to one-legged training

NASA Technical Reports Server (NTRS)

Ray, C. A.

1999-01-01

The purpose of the present study was to determine the effect of leg exercise training on sympathetic nerve responses at rest and during dynamic exercise. Six men were trained by using high-intensity interval and prolonged continuous one-legged cycling 4 day/wk, 40 min/day, for 6 wk. Heart rate, mean arterial pressure (MAP), and muscle sympathetic nerve activity (MSNA; peroneal nerve) were measured during 3 min of upright dynamic one-legged knee extensions at 40 W before and after training. After training, peak oxygen uptake in the trained leg increased 19 +/- 2% (P < 0.01). At rest, heart rate decreased from 77 +/- 3 to 71 +/- 6 beats/min (P < 0.01) with no significant changes in MAP (91 +/- 7 to 91 +/- 11 mmHg) and MSNA (29 +/- 3 to 28 +/- 1 bursts/min). During exercise, both heart rate and MAP were lower after training (108 +/- 5 to 96 +/- 5 beats/min and 132 +/- 8 to 119 +/- 4 mmHg, respectively, during the third minute of exercise; P < 0.01). MSNA decreased similarly from rest during the first 2 min of exercise both before and after training. However, MSNA was significantly less during the third minute of exercise after training (32 +/- 2 to 22 +/- 3 bursts/min; P < 0.01). This training effect on MSNA remained when MSNA was expressed as bursts per 100 heartbeats. Responses to exercise in five untrained control subjects were not different at 0 and 6 wk. These results demonstrate that exercise training prolongs the decrease in MSNA during upright leg exercise and indicates that attenuation of MSNA to exercise reported with forearm training also occurs with leg training.

Light-load resistance exercise increases muscle protein synthesis and hypertrophy signaling in elderly men.

PubMed

Agergaard, Jakob; Bülow, Jacob; Jensen, Jacob K; Reitelseder, Søren; Drummond, Micah J; Schjerling, Peter; Scheike, Thomas; Serena, Anja; Holm, Lars

2017-04-01

The present study investigated whether well-tolerated light-load resistance exercise (LL-RE) affects skeletal muscle fractional synthetic rate (FSR) and anabolic intracellular signaling as a way to counteract age-related loss of muscle mass. Untrained healthy elderly (>65-yr-old) men were subjected to 13 h of supine rest. After 2.5 h of rest, unilateral LL-RE, consisting of leg extensions (10 sets, 36 repetitions) at 16% of 1 repetition maximum (RM), was conducted. Subsequently, the subjects were randomized to oral intake of 4 g of whey protein per hour (PULSE, n = 10), 28 g of whey protein at 0 h and 12 g of whey protein at 7 h postexercise (BOLUS, n = 10), or 4 g of maltodextrin per hour (placebo, n = 10). Quadriceps muscle biopsies were taken at 0, 3, 7, and 10 h postexercise from the resting and the exercised leg of each subject. Myofibrillar FSR and activity of select targets from the mechanistic target of rapamycin complex 1-signaling cascade were analyzed from the biopsies. LL-RE increased myofibrillar FSR compared with the resting leg throughout the 10-h postexercise period. Phosphorylated (T308) AKT expression increased in the exercised leg immediately after exercise. This increase persisted in the placebo group only. Levels of phosphorylated (T37/46) eukaryotic translation initiation factor 4E-binding protein 1 increased throughout the postexercise period in the exercised leg in the placebo and BOLUS groups and peaked at 7 h. In all three groups, phosphorylated (T56) eukaryotic elongation factor 2 decreased in response to LL-RE. We conclude that resistance exercise at only 16% of 1 RM increased myofibrillar FSR, irrespective of nutrient type and feeding pattern, which indicates an anabolic effect of LL-RE in elderly individuals. This finding was supported by increased signaling for translation initiation and translation elongation in response to LL-RE. Copyright © 2017 the American Physiological Society.

Effect of hand-arm exercise on venous blood constituents during leg exercise

NASA Technical Reports Server (NTRS)

Wong, N.; Silver, J. E.; Greenawalt, S.; Kravik, S. E.; Geelen, G.

1985-01-01

Contributions by ancillary hand and arm actions to the changes in blood constituents effected by leg exercises on cycle ergometer were assessed. Static or dynamic hand-arm exercises were added to the leg exercise (50 percent VO2 peak)-only control regimens for the subjects (19-27 yr old men) in the two experimental groups. Antecubital venous blood was analyzed at times 0, 15, and 30 min (T0, T15, and T30) for serum Na(+), K(+), osmolality, albumin, total CA(2+), and glucose; blood hemoglobin, hematocrit, and lactic acid; and change in plasma volume. Only glucose and lactate values were affected by additional arm exercise. Glucose decreased 4 percent at T15 and T30 after static exercise, and by 2 percent at T15 (with no change at T30) after dynamic arm exercise. Conversely, lactic acid increased by 20 percent at T30 after static exercise, and by 14 percent by T15 and 6 percent at T30 after dynamic arm exercise. It is concluded that additional arm movements, performed usually when gripping the handle-bar on the cycle ergometer, could introduce significant errors in measured venous concentrations of glucose and lactate in the leg-exercised subjects.

Time kinetics of acute changes in muscle architecture in response to resistance exercise.

PubMed

Csapo, Robert; Alegre, Luis M; Baron, Ramon

2011-05-01

The study aimed to assess acute changes in muscle architecture and its recovery after exhaustive exercise. We hypothesised that repetitive leg press exercise would decrease vastus lateralis fascicle length, while increasing both muscle thickness and pennation angles. By investigating the time kinetics of recovery of these parameters, we wished to gain insight into the mechanisms responsible for muscle architectural changes during exercise. Muscle architecture was assessed in 41 male volunteers (25.2±3.7 yrs; 1.78±0.06 m; 76.4±11.7 kg) before and directly after, as well as 5, 10, 15, and 30 min after induction of fatigue by leg press exercise. Vastus lateralis muscle thickness, pennation angles and fascicle lengths were measured at rest by ultrasonography. Muscular fatigue was induced by an exhaustive series of maximum power, single leg press repetitions. Following leg press exercise vastus lateralis muscle thickness and pennation angles were increased by approximately 7 and 10%, whereas fascicle lengths decreased by 2%. Different recovery times (muscle thickness: 30 min; pennation angles: 15 min; fascicle lengths: 5 min) were observed. The differential time courses of recovery suggest that changes in muscle thickness, pennation angles, and fascicle lengths are driven by different exercise-related stimuli. Increased muscle perfusion and tendon creep are likely candidates accounting for short-term changes in muscle architecture. Copyright © 2011 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Liver and Muscle Contribute Differently to the Plasma Acylcarnitine Pool During Fasting and Exercise in Humans.

PubMed

Xu, G; Hansen, J S; Zhao, X J; Chen, S; Hoene, M; Wang, X L; Clemmesen, J O; Secher, N H; Häring, H U; Pedersen, B K; Lehmann, R; Weigert, Cora; Plomgaard, Peter

2016-12-01

Plasma acylcarnitine levels are elevated by physiological conditions such as fasting and exercise but also in states of insulin resistance and obesity. To elucidate the contribution of liver and skeletal muscle to plasma acylcarnitines in the fasting state and during exercise in humans. In 2 independent studies, young healthy males were fasted overnight and performed an acute bout of exercise to investigate either acylcarnitines in skeletal muscle biopsies and arterial-to-venous plasma differences over the exercising and resting leg (n = 9) or the flux over the hepato-splanchnic bed (n = 10). In the fasting state, a pronounced release of C2- and C3-carnitines from the hepato-splanchnic bed and an uptake of free carnitine by the legs were detected. Exercise further increased the release of C3-carnitine from the hepato-splanchnic bed and the uptake of free carnitine in the exercising leg. In plasma and in the exercising muscle, exercise induced an increase of most acylcarnitines followed by a rapid decline to preexercise values during recovery. In contrast, free carnitine was decreased in the exercising muscle and quickly restored thereafter. C8-, C10-, C10:1-, C12-, and C12:1-carnitines were released from the exercising leg and simultaneously; C6, C8, C10, C10:1, C14, and C16:1 were taken up by the hepato-splanchnic. These data provide novel insight to the organo-specific release/uptake of acylcarnitines. The liver is a major contributor to systemic short chain acylcarnitines, whereas the muscle tissue releases mostly medium chain acylcarnitines during exercise, indicating that other tissues are contributing to the systemic increase in long chain acylcarnitines.

Inhibition of KATP channel activity augments baroreflex-mediated vasoconstriction in exercising human skeletal muscle

PubMed Central

Keller, David Melvin; Ogoh, Shigehiko; Greene, Shane; Olivencia-Yurvati, A; Raven, Peter B

2004-01-01

In the present investigation we examined the role of ATP-sensitive potassium (KATP) channel activity in modulating carotid baroreflex (CBR)-induced vasoconstriction in the vasculature of the leg. The CBR control of mean arterial pressure (MAP) and leg vascular conductance (LVC) was determined in seven subjects (25 ± 1 years, mean ± s.e.m.) using the variable-pressure neck collar technique at rest and during one-legged knee extension exercise. The oral ingestion of glyburide (5 mg) did not change mean arterial pressure (MAP) at rest (86 versus 89 mmHg, P > 0.05), but did appear to increase MAP during exercise (87 versus 92 mmHg, P = 0.053). However, the CBR–MAP function curves were similar at rest before and after glyburide ingestion. The CBR-mediated decrease in LVC observed at rest (∼39%) was attenuated during exercise in the exercising leg (∼15%, P < 0.05). Oral glyburide ingestion partially restored CBR-mediated vasoconstriction in the exercising leg (∼40% restoration, P < 0.05) compared to control exercise. These findings indicate that KATP channel activity modulates sympathetic vasoconstriction in humans and may prove to be an important mechanism by which functional sympatholysis operates in humans during exercise. PMID:15345750

Dyssynchronous breathing during arm but not leg exercise in patients with chronic airflow obstruction.

PubMed

Celli, B R; Rassulo, J; Make, B J

1986-06-05

Some patients with chronic airflow obstruction experience dyspnea with mild arm exercise but not with more-intense leg exercise. To investigate why these patients have limited endurance during arm exertion, we studied ventilatory responses to exercise with unsupported arms in 12 patients with chronic airflow obstruction (mean [+/- SD] forced expiratory volume in one second, 0.68 +/- 0.28 liters). Unloaded leg cycling was also studied for comparison. In the five patients who had the most severe airflow obstruction, arm exercise was limited by dyspnea after 3.3 +/- 0.7 minutes, and dyssynchronous thoracoabdominal breathing developed. In the other seven patients, arm exercise was limited by the sensation of muscle fatigue after 6.1 +/- 2.0 minutes (P less than 0.05), and dyssynchronous breathing did not occur. None of the 12 patients had dyssynchronous breathing during unloaded leg cycling. Maximal transdiaphragmatic pressure, a measure of diaphragmatic fatigue, declined similarly after arm and leg exercise in both groups. During unsupported arm work, the accessory muscles of inspiration help position the torso and arms. We hypothesize that the extra demand placed on these muscles during arm exertion leads to early fatigue, an increased load on the diaphragm, and dyssynchronous thoracoabdominal inspirations. This sequence may contribute to dyspnea and limited endurance during upper-extremity exercise.

(31)P cardiac magnetic resonance spectroscopy during leg exercise at 3 Tesla.

PubMed

Hudsmith, Lucy E; Tyler, Damian J; Emmanuel, Yaso; Petersen, Steffen E; Francis, Jane M; Watkins, Hugh; Clarke, Kieran; Robson, Matthew D; Neubauer, Stefan

2009-12-01

Investigation of phosphorus ((31)P) magnetic resonance spectroscopy under stress conditions provides a non-invasive tool to examine alterations in cardiac high-energy phosphate metabolism that may not be evident at rest. Our aim was to establish cardiac (31)P MR spectroscopy during leg exercise at 3T. The increased field strength should provide a higher signal to noise ratio than at lower field strengths. Furthermore, relatively high temporal resolution at a sufficiently fine spatial resolution should be feasible. (31)P MR spectra were obtained with a 3D acquisition weighted chemical shift imaging sequence in 20 healthy volunteers at rest, during dynamic physiological leg exercise and after recovery at 3T. Haemodynamic measurements were made throughout and the rate pressure product calculated. With exercise, the mean heart rate increased by 73%, achieving a mean increase in rate pressure product of 115%. The corrected PCr/ATP ratio for subjects at rest was 2.02 +/- 0.43, exercise 2.14 +/- 0.67 (P = 0.54 vs. rest) and at recovery 2.03 +/- 0.52 (P = 0.91 vs. rest, P = 0.62 vs. exercise). A cardiac (31)P MR spectroscopy physiological exercise-recovery protocol is feasible at 3T. There was no significant change in high-energy cardiac phosphate metabolite concentrations in healthy volunteers at rest, during physiological leg exercise or during recovery. When applied to patients with heart disease, this protocol should provide insights into physiological and pathological cardiac metabolism.

The acute hormonal response to free weight and machine weight resistance exercise.

PubMed

Shaner, Aaron A; Vingren, Jakob L; Hatfield, Disa L; Budnar, Ronald G; Duplanty, Anthony A; Hill, David W

2014-04-01

Resistance exercise can acutely increase the concentrations of circulating neuroendocrine factors, but the effect of mode on this response is not established. The purpose of this study was to examine the effect of resistance exercise selection on the acute hormonal response using similar lower-body multijoint movement free weight and machine weight exercises. Ten resistance trained men (25 ± 3 years, 179 ± 7 cm, 84.2 ± 10.5 kg) completed 6 sets of 10 repetitions of squat or leg press at the same relative intensity separated by 1 week. Blood samples were collected before (PRE), immediately after (IP), and 15 (P15) and 30 minutes (P30) after exercise, and analyzed for testosterone (T), growth hormone (GH), and cortisol (C) concentrations. Exercise increased (p ≤ 0.05) T and GH at IP, but the concentrations at IP were greater for the squat (T: 31.4 ± 10.3 nmol·L(-1); GH: 9.5 ± 7.3 μg·L(-1)) than for the leg press (T: 26.9 ± 7.8 nmol·L(-1); GH: 2.8 ± 3.2 μg·L(-1)). At P15 and P30, GH was greater for the squat (P15: 12.3 ± 8.9 μg·L(-1); P30: 12.0 ± 8.9 μg·L(-1)) than for the leg press (P15: 4.8 ± 3.4 μg·L(-1); P30: 5.4 ± 4.1 μg·L(-1)). C was increased after exercise and was greater for the squat than for the leg press. Although total work (external load and body mass moved) was greater for the squat than for the leg press, rating of perceived exertion did not differ between the modes. Free weight exercises seem to induce greater hormonal responses to resistance exercise than machine weight exercises using similar lower-body multijoint movements and primary movers.

Effects of prior heavy exercise on VO(2) kinetics during heavy exercise are related to changes in muscle activity.

PubMed

Burnley, Mark; Doust, Jonathan H; Ball, Derek; Jones, Andrew M

2002-07-01

We hypothesized that the elevated primary O(2) uptake (VO(2)) amplitude during the second of two bouts of heavy cycle exercise would be accompanied by an increase in the integrated electromyogram (iEMG) measured from three leg muscles (gluteus maximus, vastus lateralis, and vastus medialis). Eight healthy men performed two 6-min bouts of heavy leg cycling (at 70% of the difference between the lactate threshold and peak VO(2)) separated by 12 min of recovery. The iEMG was measured throughout each exercise bout. The amplitude of the primary VO(2) response was increased after prior heavy leg exercise (from mean +/- SE 2.11 +/- 0.12 to 2.44 +/- 0.10 l/min, P < 0.05) with no change in the time constant of the primary response (from 21.7 +/- 2.3 to 25.2 +/- 3.3 s), and the amplitude of the VO(2) slow component was reduced (from 0.79 +/- 0.08 to 0.40 +/- 0.08 l/min, P < 0.05). The elevated primary VO(2) amplitude after leg cycling was accompanied by a 19% increase in the averaged iEMG of the three muscles in the first 2 min of exercise (491 +/- 108 vs. 604 +/- 151% increase above baseline values, P < 0.05), whereas mean power frequency was unchanged (80.1 +/- 0.9 vs. 80.6 +/- 1.0 Hz). The results of the present study indicate that the increased primary VO(2) amplitude observed during the second of two bouts of heavy exercise is related to a greater recruitment of motor units at the onset of exercise.

Carotid baroreflex control of leg vasculature in exercising and non-exercising skeletal muscle in humans

PubMed Central

Melvin Keller, David; Fadel, Paul J; Ogoh, Shigehiko; Matthew Brothers, Robert; Hawkins, Megan; Olivencia-Yurvati, Al; Raven, Peter B

2004-01-01

Carotid baroreflex (CBR) function was examined in five men and three women (25 ± 1 years) using the variable-pressure neck collar technique at rest and during dynamic, one-legged knee extension exercise at 7 W and 25 W. The CBR exhibited control of leg vascular conductance (LVC) at rest and during exercise in both an exercising leg (EL) and a non-exercising leg (NEL) across a wide range of pressures from +40 Torr neck pressure (NP) to −80 Torr neck suction (NS). Specifically, increases in LVC (% change) in response to NS were no different across −20 to −80 Torr in either EL or NEL compared to rest, P > 0.05. However, CBR-mediated decreases in percentage LVC in response to NP were attenuated in EL at both 7 W (16 ± 1%) and 25 W (12 ± 1%) compared to rest (40 ± 3%; P < 0.05) as well as compared to responses in the NEL (36 ± 6% at 7 W and 36 ± 7% at 25 W; P < 0.05). This decrease in vascular responsiveness in EL was associated with a reduction in the gain of the percentage muscle sympathetic nerve activity (%MSNA)–%LVC relationship compared to rest (P < 0.05). Collectively, these data indicate that, despite a clear attenuation of the vascular response to MSNA in the exercising leg, CBR-mediated changes in mean arterial pressure were no different between rest and exercise. PMID:15388778

Comparison between Unilateral and Bilateral Plyometric Training on Single and Double Leg Jumping Performance and Strength.

PubMed

Bogdanis, Gregory C; Tsoukos, Athanasios; Kaloheri, Olga; Terzis, Gerasimos; Veligekas, Panagiotis; Brown, Lee E

2017-04-18

This study compared the effects of unilateral and bilateral plyometric training on single and double-leg jumping performance, maximal strength and rate of force development (RFD). Fifteen moderately trained subjects were randomly assigned to either a unilateral (U, n=7) or bilateral group (B, n=8). Both groups performed maximal effort plyometric leg exercises two times per week for 6 weeks. The B group performed all exercises with both legs, while the U group performed half the repetitions with each leg, so that total exercise volume was the same. Jumping performance was assessed by countermovement jumps (CMJ) and drop jumps (DJ), while maximal isometric leg press strength and RFD were measured before and after training for each leg separately and both legs together. CMJ improvement with both legs was not significantly different between U (12.1±7.2%) and B (11.0±5.5%) groups. However, the sum of right and left leg CMJ only improved in the U group (19.0±7.1%, p<0.001) and was unchanged in the B group (3.4±8.4%, p=0.80). Maximal isometric leg press force with both legs was increased similarly between groups (B: 20.1±6.5%, U: 19.9±6.2%). However, the sum of right and left leg maximal force increased more in U compared to B group (23.8±9.1% vs. 11.9±6.2%, p=0.009, respectively). Similarly, the sum of right and left leg RFD0-50 and RFD0-100 were improved only in the U group (34-36%, p<0.01). Unilateral plyometric training was more effective at increasing both single and double-leg jumping performance, isometric leg press maximal force and RFD when compared to bilateral training.

Individual Muscle use in Hamstring Exercises by Soccer Players Assessed using Functional MRI.

PubMed

Fernandez-Gonzalo, R; Tesch, P A; Linnehan, R M; Kreider, R B; Di Salvo, V; Suarez-Arrones, L; Alomar, X; Mendez-Villanueva, A; Rodas, G

2016-06-01

This study used functional magnetic resonance imaging (fMRI) to compare individual muscle use in exercises aimed at preventing hamstring injuries. Thirty-six professional soccer players were randomized into 4 groups, each performing either Nordic hamstring, flywheel leg curl, Russian belt or conic-pulley exercise. MRIs were performed before and immediately after a bout of 4 sets of 8 repetitions. Pre-post exercise differences in contrast shift (T2) were analyzed for the long (BFLh) and short head (BFSh) of biceps femoris, semitendinosus (ST), semimembranosus (SM) and gracilis (GR) muscles. Flywheel leg curl increased (P<0.001) T2 of GR (95%), ST (65%), BFSh (51%) and BFLh (14%). After the Nordic hamstring, GR (39%), ST (16%) and BFSh (14%) showed increased T2 (P<0.001). Russian belt and conic-pulley exercise produced subtle (P<0.02) T2 increases of ST (9 and 6%, respectively) and BFLh (7 and 6%, respectively). Russian belt increased T2 of SM (7%). Among exercises examined, flywheel leg curl showed the most substantial hamstring and GR muscle use. However, no single exercise executed was able to increase T2 of all hamstring and synergist muscles analyzed. It is therefore suggested that multiple exercises must be carried out to bring in, and fully activate all knee flexors and hip extensors. © Georg Thieme Verlag KG Stuttgart · New York.

Atorvastatin Increases Exercise Leg Blood Flow in Healthy Adults

PubMed Central

Parker, Beth A.; Capizzi, Jeffrey A.; Augeri, Amanda L.; Grimaldi, Adam S.; White, C. Michael; Thompson, Paul D.

2011-01-01

OBJECTIVES We sought to examine the effect of atorvastatin therapy on exercise leg blood flow in healthy middle-aged and older, men and women. BACKGROUND The vasodilatory response to exercise decreases in humans with aging and disease and this reduction may contribute to reduced exercise capacity. METHODS We used a double-blind, randomly assigned, placebo-controlled protocol to assess the effect of atorvastatin treatment on exercising leg hemodynamics. We measured femoral artery blood flow (FBF) using Doppler ultrasound and calculated femoral vascular conductance (FVC) from brachial mean arterial pressure (MAP) before and during single knee-extensor exercise in healthy adults (ages 40–71) before (PRE) and after (POST) 6 months of 80 mg atorvastatin (A: 14 men, 16 women) or placebo (P: 14 men, 22 women) treatment. FBF and FVC were normalized to exercise power output and estimated quadriceps muscle mass. RESULTS Atorvastatin reduced LDL cholesterol by approximately 50%, but not in the placebo group (p < 0.01). Atorvastatin also increased exercise FBF from 44.2 ± 19.0 to 51.4 ± 22.0 mL/min/W/kg muscle whereas FBF in the placebo group was unchanged (40.1 ± 16.0 vs 39.5 ± 16.1) (p <0.01). FVC also increased with atorvastatin from 0.5 ± 0.2 to. 0.6 ± 0.2 mL/min/mmHg/W/kg muscle, but not in the placebo subjects (P: 0.4 ± 0.2 vs 0.4 ± 0.2) ( p < 0.01). CONCLUSIONS High-dose atorvastatin augments exercising leg hyperemia. Statins may mitigate reductions in the exercise vasodilatory response in humans that are associated with aging and disease. PMID:22018642

Leucine, Not Total Protein, Content of a Supplement Is the Primary Determinant of Muscle Protein Anabolic Responses in Healthy Older Women.

PubMed

Devries, Michaela C; McGlory, Chris; Bolster, Douglas R; Kamil, Alison; Rahn, Maike; Harkness, Laura; Baker, Steven K; Phillips, Stuart M

2018-06-13

Older adults show a blunted muscle protein synthesis (MPS) response to postprandial hyperaminoacidemia relative to younger adults. Evidence suggests that this anabolic resistance can be overcome by consuming greater quantities of leucine. The purpose of this trial was to determine whether the addition of leucine to a smaller dose (10 g) of milk proteins would, when compared with a larger dose (25 g) of whey protein isolate (WPI), result in similar increases in acute (hourly) and integrated (daily) myofibrillar protein synthesis (myoPS). Healthy older (mean ± SD age: 69 ± 1 y) women (n = 11/group) were randomly assigned with the use of a single-blind, parallel-group design to twice-daily consumption of either WPI [25 g WPI (3 g l-leucine)] or leucine (LEU; 10 g milk protein with 3 g total l-leucine) for 6 d. Participants performed unilateral resistance exercise to allow assessment of the impact of the supplement alone and with resistance exercise. We determined acute (13C6-phenylanine) and integrated [using deuterated water (D2O)] rates of myoPS in the fasting (acute), basal (integrated), nonexercised, and exercised states. Acute myoPS increased in both legs in response to LEU (fed: 45%; fed+exercise: 71%; P < 0.001) and WPI (fed: 29%; fed+exercise: 47%; P < 0.001) compared with fasting; the increase was greater with LEU than with WPI in the exercised leg (46%; P = 0.04) but not in the rested leg (P = 0.07). The acute myoPS response was greater in the exercised leg than in the rested leg for both WPI (63%) and LEU (58%) (P < 0.001). Integrated myoPS increased with WPI and LEU in the exercised leg (both 9%; P < 0.001) during supplementation, and with WPI (3%; P = 0.02) but not LEU (2%, P = 0.1) in the rested leg compared with the basal state. A lower-protein (10 compared with 25 g/dose), leucine-matched beverage induced similar increases in acute and integrated myoPS in healthy older women. Lower-protein supplements with added leucine may represent an advantageous approach in older adults to maintain skeletal muscle anabolic sensitivity and attenuate muscle loss; however, further work is needed using longer-term interventions to substantiate these findings. This trial was registered at www.clinicaltrials.gov as NCT02282566.

Pulmonary and leg VO2 during submaximal exercise: implications for muscular efficiency

NASA Technical Reports Server (NTRS)

Poole, D. C.; Gaesser, G. A.; Hogan, M. C.; Knight, D. R.; Wagner, P. D.

1992-01-01

Insights into muscle energetics during exercise (e.g., muscular efficiency) are often inferred from measurements of pulmonary gas exchange. This procedure presupposes that changes of pulmonary O2 (VO2) associated with increases of external work reflect accurately the increased muscle VO2. The present investigation addressed this issue directly by making simultaneous determinations of pulmonary and leg VO2 over a range of work rates calculated to elicit 20-90% of maximum VO2 on the basis of prior incremental (25 or 30 W/min) cycle ergometry. VO2 for both legs was calculated as the product of twice one-leg blood flow (constant-infusion thermodilution) and arteriovenous O2 content difference across the leg. Measurements were made 3-5 min after each work rate imposition to avoid incorporation of the VO2 slow component above the lactate threshold. For all 17 subjects, the slope of pulmonary VO2 (9.9 +/- 0.2 ml O2.W-1.min-1) was not different (P greater than 0.05) from that for leg VO2 (9.2 +/- 0.6 ml O2.W-1.min-1). Estimation of "delta" efficiency (i.e., delta work accomplished divided by delta energy expended, calculated from slope of VO2 vs. work rate and a caloric equivalent for O2 of 4.985 cal/ml) using pulmonary VO2 measurements (29.1 +/- 0.6%) was likewise not significantly different (P greater than 0.05) from that made using leg VO2 measurements (33.7 +/- 2.4%). These data suggest that the net VO2 cost of metabolic "support" processes outside the exercising legs changes little over a relatively broad range of exercise intensities. Thus, under the conditions of this investigation, changes of VO2 measured from expired gas reflected closely those occurring within the exercising legs.

Influence of muscle mass and work on post-exercise glucose and insulin responses in young untrained subjects.

PubMed

Brambrink, J K; Fluckey, J D; Hickey, M S; Craig, B W

1997-11-01

The 18 h post-exercise glucose and insulin responses of six male and six female subjects were measured following one- or two-leg cycling to determine the influence of muscle mass involvement and work. Each subject performed three exercise trials on a Cybex Met 100 cycle ergometer: (1) two-leg exercise for 30 min at 60% of the two-leg VO2 max; (2) one-leg exercise for 30 min at 60% of one-leg VO2 max; and (3) one-leg exercise (one-leg TW) at 60% of the one-leg VO2 max with the total work performed equal to that of the two-leg trial (duration approximately 50 min). These trials were preceded by 2 days of inactivity and followed by an 18 h post-exercise 75 g oral glucose tolerance test (OGTT). The glucose response during the baseline OGTT demonstrated that the subjects had normal glucose tolerance with fasting serum glucose levels of 5.1 mM, and 1 and 2 h serum glucose less than 7.8 mM, respectively. The 18 h post-exercise glucose responses were significantly lower following the two-leg trial (P < 0.05), with the area under the curve values being 129.9 mM h-1 less than the resting control level. The 18 h post-exercise insulin AUC response of the two-leg trial was significantly lower than either of the one-leg responses (14.7 pM below the one-leg and 5.0 pM below the one-leg TW) but was not associated with a change in C-peptide. The 18 h post-exercise insulin levels of the one-leg and one-leg TW trials were above or near the resting control values, but were not accompanied by a significant change in C-peptide. In conclusion, the data presented here show that the amount of muscle tissue utilized during an exercise bout can influence both the glucose and insulin responses, whereas the amount of total work employed during the exercise had no effect on either of these parameters.

Regulation of autophagy in human skeletal muscle: effects of exercise, exercise training and insulin stimulation

PubMed Central

Fritzen, Andreas M.; Madsen, Agnete B.; Kleinert, Maximilian; Treebak, Jonas T.; Lundsgaard, Anne‐Marie; Jensen, Thomas E.; Richter, Erik A.; Wojtaszewski, Jørgen; Kiens, Bente

2016-01-01

Key points Regulation of autophagy in human muscle in many aspects differs from the majority of previous reports based on studies in cell systems and rodent muscle.An acute bout of exercise and insulin stimulation reduce human muscle autophagosome content.An acute bout of exercise regulates autophagy by a local contraction‐induced mechanism.Exercise training increases the capacity for formation of autophagosomes in human muscle.AMPK activation during exercise seems insufficient to regulate autophagosome content in muscle, while mTORC1 signalling via ULK1 probably mediates the autophagy‐inhibiting effect of insulin. Abstract Studies in rodent muscle suggest that autophagy is regulated by acute exercise, exercise training and insulin stimulation. However, little is known about the regulation of autophagy in human skeletal muscle. Here we investigate the autophagic response to acute one‐legged exercise, one‐legged exercise training and subsequent insulin stimulation in exercised and non‐exercised human muscle. Acute one‐legged exercise decreased (P<0.01) lipidation of microtubule‐associated protein 1A/1B‐light chain 3 (LC3) (∼50%) and the LC3‐II/LC3‐I ratio (∼60%) indicating that content of autophagosomes decreases with exercise in human muscle. The decrease in LC3‐II/LC3‐I ratio did not correlate with activation of 5′AMP activated protein kinase (AMPK) trimer complexes in human muscle. Consistently, pharmacological AMPK activation with 5‐aminoimidazole‐4‐carboxamide riboside (AICAR) in mouse muscle did not affect the LC3‐II/LC3‐I ratio. Four hours after exercise, insulin further reduced (P<0.01) the LC3‐II/LC3‐I ratio (∼80%) in muscle of the exercised and non‐exercised leg in humans. This coincided with increased Ser‐757 phosphorylation of Unc51 like kinase 1 (ULK1), which is suggested as a mammalian target of rapamycin complex 1 (mTORC1) target. Accordingly, inhibition of mTOR signalling in mouse muscle prevented the ability of insulin to reduce the LC3‐II/LC3‐I ratio. In response to 3 weeks of one‐legged exercise training, the LC3‐II/LC3‐I ratio decreased (P<0.05) in both trained and untrained muscle and this change was largely driven by an increase in LC3‐I content. Taken together, acute exercise and insulin stimulation reduce muscle autophagosome content, while exercise training may increase the capacity for formation of autophagosomes in muscle. Moreover, AMPK activation during exercise may not be sufficient to regulate autophagy in muscle, while mTORC1 signalling via ULK1 probably mediates the autophagy‐inhibiting effect of insulin. PMID:26614120

Effect of modified bridge exercise on trunk muscle activity in healthy adults: a cross sectional study.

PubMed

Yoon, Jeong-Oh; Kang, Min-Hyeok; Kim, Jun-Seok; Oh, Jae-Seop

This is a cross-sectional study. University research laboratory. Fifteen healthy adults (mean age: 27.47 years) volunteered for this study. The individuals performed standard bridge exercise and modified bridge exercises with right leg-lift (single-leg-lift bridge exercise, single-leg-lift bridge exercise on an unstable surface, and single-leg-lift hip abduction bridge exercise). During the bridge exercises, electromyography of the rectus abdominis, internal oblique, erector spinae, and multifidus muscles was recorded using a wireless surface electromyography system. Two-way repeated-measures analysis of variance (exercise by side) with post hoc pairwise comparisons using Bonferroni correction was used to compare the electromyography data collected from each muscle. Bilateral internal oblique muscle activities showed significantly greater during single-leg-lift bridge exercise (95% confidence interval: right internal oblique=-8.99 to -1.08, left internal oblique=-6.84 to -0.10), single-leg-lift bridge exercise on an unstable surface (95% confidence interval: right internal oblique=-7.32 to -1.78, left internal oblique=-5.34 to -0.99), and single-leg-lift hip abduction bridge exercise (95% confidence interval: right internal oblique=-17.13 to -0.89, left internal oblique=-8.56 to -0.60) compared with standard bridge exercise. Bilateral rectus abdominis showed greater electromyography activity during single-leg-lift bridge exercise on an unstable surface (95% confidence interval: right rectus abdominis=-9.33 to -1.13, left rectus abdominis=-4.80 to -0.64) and single-leg-lift hip abduction bridge exercise (95% confidence interval: right rectus abdominis=-14.12 to -1.84, left rectus abdominis=-6.68 to -0.16) compared with standard bridge exercise. In addition, the right rectus abdominis muscle activity was greater during single-leg-lift hip abduction bridge exercise compared with single-leg-lift bridge exercise on an unstable surface (95% confidence interval=-7.51 to -0.89). For erector spinae, muscle activity was greater in right side compared with left side during all exercises (95% confidence interval: standard bridge exercise=0.19-4.53, single-leg-lift bridge exercise=0.24-10.49, single-leg-lift bridge exercise on an unstable surface=0.74-8.55, single-leg-lift hip abduction bridge exercise=0.47-11.43). There was no significant interaction and main effect for multifidus. Adding hip abduction and unstable conditions to bridge exercises may be useful strategy to facilitate the co-activation of trunk muscles. Copyright © 2017 Associação Brasileira de Pesquisa e Pós-Graduação em Fisioterapia. Publicado por Elsevier Editora Ltda. All rights reserved.

Graduated Compression Stockings for Runners: Friend, Foe, or Fake?

PubMed Central

Bovenschen, H. Jorn; te Booij, Mariëlle; van der Vleuten, Carine J. M.

2013-01-01

Objective: To assess the effect of graduated compression stockings (GCS) on lower leg volume and leg complaints in runners during and after exercise. Design: Cross-sectional study. Setting: Radboud University Nijmegen Medical Centre and an outdoor running track in Nijmegen, The Netherlands. Patients or Other Participants: Thirteen Dutch trained recreational runners. Intervention(s): Participants used a GCS on 1 leg during running. Main Outcome Measures: (1) Lower leg volume of both legs was measured at baseline, directly after running, and at 5 minutes and 30 minutes after running using a validated perometer. (2) Leg complaints were reported on questionnaires at set intervals. Results: (1) In both experiments, the legs with GCS showed a reduction in mean (± SEM) leg volume directly after running, as compared with the leg without GCS: −14.1 ± 7.6 mL (P = .04) for the 10-km running track and −53.5 ± 17.8 mL (P = .03) for the maximum exercise test. This effect was not observed at 5 and 30 minutes after running. (2) No differences in leg complaints were reported in either experiment. Conclusions: The GCS prevented an increase in leg volume just after the running exercise. However, this result was not accompanied by a reduction in subjective questionnaire-reported leg complaints. The practical consequences of the present findings need further study. PMID:23672387

Postexercise blood flow restriction does not enhance muscle hypertrophy induced by multiple-set high-load resistance exercise.

PubMed

Madarame, Haruhiko; Nakada, Satoshi; Ohta, Takahisa; Ishii, Naokata

2018-05-01

To test the applicability of postexercise blood flow restriction (PEBFR) in practical training programmes, we investigated whether PEBFR enhances muscle hypertrophy induced by multiple-set high-load resistance exercise (RE). Seven men completed an eight-week RE programme for knee extensor muscles. Employing a within-subject design, one leg was subjected to RE + PEBFR, whereas contralateral leg to RE only. On each exercise session, participants performed three sets of unilateral knee extension exercise at approximately 70% of their one-repetition maximum for RE leg first, and then performed three sets for RE + PEBFR leg. Immediately after completion of the third set, the proximal portion of the RE + PEBFR leg was compressed with an air-pressure cuff for 5 min at a pressure ranging from 100 to 150 mmHg. If participants could perform 10 repetitions for three sets in two consecutive exercise sessions, the work load was increased by 5% at the next exercise session. Muscle thickness and strength of knee extensor muscles were measured before and after the eight-week training period and after the subsequent eight-week detraining period. There was a main effect of time but no condition × time interaction or main effect of condition for muscle thickness and strength. Both muscle thickness and strength increased after the training period independent of the condition. This result suggests that PEBFR would not be an effective training method at least in an early phase of adaptation to high-load resistance exercise. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Oral antioxidants improve leg blood flow during exercise in patients with chronic obstructive pulmonary disease

PubMed Central

Rossman, Matthew J.; Trinity, Joel D.; Garten, Ryan S.; Ives, Stephen J.; Conklin, Jamie D.; Barrett-O'Keefe, Zachary; Witman, Melissa A. H.; Bledsoe, Amber D.; Morgan, David E.; Runnels, Sean; Reese, Van R.; Zhao, Jia; Amann, Markus; Wray, D. Walter

2015-01-01

The consequence of elevated oxidative stress on exercising skeletal muscle blood flow as well as the transport and utilization of O2 in patients with chronic obstructive pulmonary disease (COPD) is not well understood. The present study examined the impact of an oral antioxidant cocktail (AOC) on leg blood flow (LBF) and O2 consumption during dynamic exercise in 16 patients with COPD and 16 healthy subjects. Subjects performed submaximal (3, 6, and 9 W) single-leg knee extensor exercise while LBF (Doppler ultrasound), mean arterial blood pressure, leg vascular conductance, arterial O2 saturation, leg arterial-venous O2 difference, and leg O2 consumption (direct Fick) were evaluated under control conditions and after AOC administration. AOC administration increased LBF (3 W: 1,604 ± 100 vs. 1,798 ± 128 ml/min, 6 W: 1,832 ± 109 vs. 1,992 ± 120 ml/min, and 9W: 2,035 ± 114 vs. 2,187 ± 136 ml/min, P < 0.05, control vs. AOC, respectively), leg vascular conductance, and leg O2 consumption (3 W: 173 ± 12 vs. 210 ± 15 ml O2/min, 6 W: 217 ± 14 vs. 237 ± 15 ml O2/min, and 9 W: 244 ± 16 vs 260 ± 18 ml O2/min, P < 0.05, control vs. AOC, respectively) during exercise in COPD, whereas no effect was observed in healthy subjects. In addition, the AOC afforded a small, but significant, improvement in arterial O2 saturation only in patients with COPD. Thus, these data demonstrate a novel beneficial role of AOC administration on exercising LBF, O2 consumption, and arterial O2 saturation in patients with COPD, implicating oxidative stress as a potential therapeutic target for impaired exercise capacity in this population. PMID:26188020

Using squat repetition maximum testing to determine hamstring resistance training exercise loads.

PubMed

Ebben, William P; Long, Nicholas J; Pawlowski, Zach D; Chmielewski, Lauren M; Clewien, Rustin W; Jensen, Randall L

2010-02-01

The purpose of this study was to determine whether there is a linear relationship between the squat and a variety of hamstring resistance training exercises, and whether this relationship differs on the basis of sex. This study also sought to create prediction equations for the determination of hamstring exercise load based on the squat load. Repetition maximums of the squat, as well as 4 common hamstring resistance training exercises including the seated leg curl, stiff leg dead lift, single leg dead lift, and good morning exercise, were determined for each subject. Subjects included 21 men and 13 women collegiate athletes. Data were evaluated using linear regression analysis to predict hamstring exercise loads from 6 repetition maximum squat data. Results of the analysis of all subjects indicated that squat load was a significant predictor of loads for each of the hamstring exercises. However, separate analysis of women revealed that squat load was not a significant predictor of loads for any of the hamstring exercises. Analysis of the men revealed that squat was a significant predictor of load for the seated leg curl (R = 0.58, p < 0.001), stiff leg dead lift (R = 0.82, p < 0.001), single leg stiff leg dead lift (R = 0.80, p < 0.001), and good morning (R = 0.79, p < 0.001) exercises. On the basis of the analysis of the men, the following prediction equations were devised for each exercise: (1) seated leg curl load = squat load (0.186) + 10.935 kg, (2) stiff leg deadlift load = squat load (1.133) - 86.331 kg, (3) single leg stiff leg deadlift load = squat load (0.443) - 3.425 kg, and (4) good morning load = squat load (0.961) - 105.505 kg. Thus, results from testing core exercises such as the squat can provide useful data for the assignment of loads for assistance exercises.

Carryover effect of hip and knee exercises program on functional performance in individuals with patellofemoral pain syndrome

PubMed Central

Ahmed Hamada, Hamada; Hussein Draz, Amira; Koura, Ghada Mohamed; Saab, Ibtissam M.

2017-01-01

[Purpose] This study was carried out to investigate the carryover effect of hip and knee exercises program on functional performance (single legged hop test as functional performance test and Kujala score for functional activities). [Subjects and Methods] Thirty patients with patellofemoral pain syndrome were randomly assigned into two equal groups. Group (A) consisted of 15 patients undergoing hip strengthening exercises for four weeks then measuring all variables followed by additional four weeks of knee exercises program then measuring all variables again. Group (B): consisted of 15 patients undergoing knee exercises program for four weeks then measuring all variables followed by additional four weeks of hip strengthening exercises then measuring all variables. Functional abilities and knee muscles performance were assessed using Kujala questionnaire and single legged hop test respectively pre and after the completion of the first 4 weeks then after 8 weeks for both groups. [Results] Significantly increase in Kujala questionnaire in group A compared with group B was observed. While, there were significant increase in single legged hop performance test in group B compared with group A. [Conclusion] Starting with hip exercises improve the performance of subjects more than functional activities while starting with knee exercises improve the functional activities of subjects more than performance. PMID:28878459

Carryover effect of hip and knee exercises program on functional performance in individuals with patellofemoral pain syndrome.

PubMed

Ahmed Hamada, Hamada; Hussein Draz, Amira; Koura, Ghada Mohamed; Saab, Ibtissam M

2017-08-01

[Purpose] This study was carried out to investigate the carryover effect of hip and knee exercises program on functional performance (single legged hop test as functional performance test and Kujala score for functional activities). [Subjects and Methods] Thirty patients with patellofemoral pain syndrome were randomly assigned into two equal groups. Group (A) consisted of 15 patients undergoing hip strengthening exercises for four weeks then measuring all variables followed by additional four weeks of knee exercises program then measuring all variables again. Group (B): consisted of 15 patients undergoing knee exercises program for four weeks then measuring all variables followed by additional four weeks of hip strengthening exercises then measuring all variables. Functional abilities and knee muscles performance were assessed using Kujala questionnaire and single legged hop test respectively pre and after the completion of the first 4 weeks then after 8 weeks for both groups. [Results] Significantly increase in Kujala questionnaire in group A compared with group B was observed. While, there were significant increase in single legged hop performance test in group B compared with group A. [Conclusion] Starting with hip exercises improve the performance of subjects more than functional activities while starting with knee exercises improve the functional activities of subjects more than performance.

The efficacy of early initiated, supervised, progressive resistance training compared to unsupervised, home-based exercise after unicompartmental knee arthroplasty: a single-blinded randomized controlled trial.

PubMed

Jørgensen, Peter B; Bogh, Søren B; Kierkegaard, Signe; Sørensen, Henrik; Odgaard, Anders; Søballe, Kjeld; Mechlenburg, Inger

2017-01-01

To examine if supervised progressive resistance training was superior to home-based exercise in rehabilitation after unicompartmental knee arthroplasty. Single blinded, randomized clinical trial. Surgery, progressive resistance training and testing was carried out at Aarhus University Hospital and home-based exercise was carried out in the home of the patient. Fifty five patients were randomized to either progressive resistance training or home-based exercise. Patients were randomized to either progressive resistance training (home based exercise five days/week and progressive resistance training two days/week) or control group (home based exercise seven days/week). Preoperative assessment, 10-week (primary endpoint) and one-year follow-up were performed for leg extension power, spatiotemporal gait parameters and knee injury and osteoarthritis outcome score (KOOS). Forty patients (73%) completed 1-year follow-up. Patients in the progressive resistance training group participated in average 11 of 16 training sessions. Leg extension power increased from baseline to 10-week follow-up in progressive resistance training group (progressive resistance training: 0.28 W/kg, P= 0.01, control group: 0.01 W/kg, P=0.93) with no between-group difference. Walking speed and KOOS scores increased from baseline to 10-week follow-up in both groups with no between-group difference (six minutes walk test P=0.63, KOOS P>0.29). Progressive resistance training two days/week combined with home based exercise five days/week was not superior to home based exercise seven days/week in improving leg extension power of the operated leg.

Muscle fiber type-specific response of Hsp70 expression in human quadriceps following acute isometric exercise.

PubMed

Tupling, A R; Bombardier, E; Stewart, R D; Vigna, C; Aqui, A E

2007-12-01

To investigate the time course of fiber type-specific heat shock protein 70 (Hsp70) expression in human skeletal muscle after acute exercise, 10 untrained male volunteers performed single-legged isometric knee extensor exercise at 60% of their maximal voluntary contraction (MVC) with a 50% duty cycle (5-s contraction and 5-s relaxation) for 30 min. Muscle biopsies were collected from the vastus lateralis before (Pre) exercise in the rested control leg (C) and immediately after exercise (Post) in the exercised leg (E) only and on recovery days 1 (R1), 2 (R2), 3 (R3), and 6 (R6) from both legs. As demonstrated by Western blot analysis, whole muscle Hsp70 content was unchanged (P > 0.05) immediately after exercise (Pre vs. Post), was increased (P < 0.05) by approximately 43% at R1, and remained elevated throughout the entire recovery period in E only. Hsp70 expression was also assessed in individual muscle fiber types I, IIA, and IIAX/IIX by immunohistochemistry. There were no fiber type differences (P > 0.05) in basal Hsp70 expression. Immediately after exercise, Hsp70 expression was increased (P < 0.05) in type I fibers by approximately 87% but was unchanged (P > 0.05) in type II fibers (Pre vs. Post). At R1 and throughout recovery, Hsp70 content in E was increased above basal levels (P < 0.05) in all fiber types, but Hsp70 expression was always highest (P < 0.05) in type I fibers. Hsp70 content in C was not different from Pre at any time throughout recovery. Glycogen depletion was observed at Post in all type II, but not type I, fibers, suggesting that the fiber type differences in exercise-induced Hsp70 expression were not related to glycogen availability. These results demonstrate that the time course of exercise-induced Hsp70 expression in human skeletal muscle is fiber type specific.

The Interaction of Fatigue and Potentiation Following an Acute Bout of Unilateral Squats.

PubMed

Andrews, Samantha K; Horodyski, Jesse M; MacLeod, Daniel A; Whitten, Joseph; Behm, David G

2016-12-01

A prior conditioning resistance exercise can augment subsequent performance of the affected muscles due to the effects of post-activation potentiation (PAP). The non-local muscle fatigue literature has illustrated the global neural effects of unilateral fatigue. However, no studies have examined the possibility of acute non-local performance enhancements. The objective of the study was to provide a conditioning stimulus in an attempt to potentiate the subsequent jump performance of the affected limb and determine if there were performance changes in the contralateral limb. Using a randomized allocation, 14 subjects (6 females, 8 males) completed three conditions on separate days: 1) unilateral, dominant leg, Bulgarian split squat protocol with testing of the exercised leg, 2) unilateral, dominant leg, Bulgarian split squat protocol with testing of the contralateral, non-exercised leg and 3) control session with testing of the non-dominant leg. Pre- and post-testing consisted of countermovement (CMJ) and drop jumps (DJ). The exercised leg exhibited CMJ height increases of 3.5% (p = 0.008; d = 0.28), 4.0% (p = 0.011; d = 0.33) and 3.2% (p = 0.013; d = 0.26) at 1, 5, and 10 min post-intervention respectively. The contralateral CMJ height had 2.0% (p = 0.034; d = 0.18), 1.2% (p = 0.2; d = 0.12), and 2.1% (p = 0.05; d = 0.17) deficits at 1, 5, and 10 min post-intervention respectively. Similar relative results were found for CMJ power. There were no significant interactions for DJ measures or control CMJ measures. The findings suggest that PAP effects were likely predominant for the exercised leg whereas the conditioning exercise provided trivial magnitude although statistically significant neural impairments for the contralateral limb.

Rapid switch-off of the human myosin heavy chain IIX gene after heavy load muscle contractions is sustained for at least four days.

PubMed

Andersen, J L; Gruschy-Knudsen, T

2018-02-01

Long-term heavy load contractions decrease the relative amount of the myosin heavy chain (MHC) IIX isoform in human skeletal muscle, but the timing of the down-regulation in the short term is unknown. Untrained subjects performed two resistance bouts, in two consecutive days, with one leg, the other leg serving as a control (age 24±1, n=5). Muscle biopsies were obtained in both legs before, immediately after, and 24, 54, and 96 hours after exercise. Serial cryosection analysis combined immunohistochemistry and ATPase histochemistry with In Situ hybridization to identify the distribution of MHC isoforms and their corresponding transcripts, enabling identification of transitional fibers. Fibers positive solely for MHC IIX mRNA decreased in the exercised leg throughout the study period. At 96 hours post-exercise, no fibers solely expressed MHC IIX mRNA. In contrast, the number of fibers expressing MHC IIA mRNA increased throughout the study period. The percentage of fibers expressing mRNA for MHC I was unchanged in both legs at all time points. Pronounced depletion of glycogen in the MHC IIX fibers of the exercised leg verifies that the type IIX fibers were active during the heavy load contractions. Major mismatch between MHC at the mRNA and protein levels was only found in the fibers of the exercised leg. These data provide unequivocal in situ evidence of an immediate shutdown of the MHC IIX gene after resistance exercise. A further novel finding was that the silencing of the MHC IIX gene is sustained at least 4 days after removal of the stimulus. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The Effect of Commonly Performed Exercises on the Levator Hiatus Area and the Length and Strength of Pelvic Floor Muscles in Postpartum Women.

PubMed

Siff, Lauren N; Hill, Audra J; Walters, Samantha J; Walters, Ginny; Walters, Mark D

2018-05-02

The aim oft his study was to compare the effects of 10 common exercises to traditional pelvic floor muscle (PFM) contractions (Kegel) on levator hiatus (LH) area and PFM length and strength. This is a cross-sectional study of 15 healthy postpartum women. Ten exercises were studied. These were common variations of leg, core, and back exercises used in yoga, Pilates, strength training, and physical therapy. Each participant performed all 10 exercises at a single visit in 2 examination settings: transperineal ultrasound and perineometry. Ultrasound measured the LH area and PFM length, and perineometry measured the muscle strength (peak squeeze pressure). Kegel generates an increase in squeeze pressure (24.3 cm H2O), shortens the muscles (-0.46 cm) and narrows the LH (-0.13 cm). The bird-dog and plank exercises were not different from Kegel in any measurement. While the leg-lift ultrasound dimensions are similar to Kegel, leg lifts generated peak squeeze pressures stronger than any other exercise (including Kegel). Whereas ultrasound dimensions were similar to Kegel, tucked and untucked squats and thigh adductions generated weaker contractions than Kegel. While crunch generated a squeeze pressure similar to Kegel, the ultrasound dimensions showed a significantly wider LH and longer muscle than Kegel. Bridge, clam, and plié exercises affected the PFMs differently than Kegel in all measures. Bird-dog, plank, and leg-lift exercises should be evaluated as alternative exercises to Kegel as they affect PFM strength and length and LH area similarly to Kegel, and leg lifts generate a stronger contraction than Kegel.

Hemodynamic responses to small muscle mass exercise in heart failure patients with reduced ejection fraction

PubMed Central

Barrett-O'Keefe, Zachary; Lee, Joshua F.; Berbert, Amanda; Witman, Melissa A. H.; Nativi-Nicolau, Jose; Stehlik, Josef; Richardson, Russell S.

2014-01-01

To better understand the mechanisms responsible for exercise intolerance in heart failure with reduced ejection fraction (HFrEF), the present study sought to evaluate the hemodynamic responses to small muscle mass exercise in this cohort. In 25 HFrEF patients (64 ± 2 yr) and 17 healthy, age-matched control subjects (64 ± 2 yr), mean arterial pressure (MAP), cardiac output (CO), and limb blood flow were examined during graded static-intermittent handgrip (HG) and dynamic single-leg knee-extensor (KE) exercise. During HG exercise, MAP increased similarly between groups. CO increased significantly (+1.3 ± 0.3 l/min) in the control group, but it remained unchanged across workloads in HFrEF patients. At 15% maximum voluntary contraction (MVC), forearm blood flow was similar between groups, while HFrEF patients exhibited an attenuated increase at the two highest intensities compared with controls, with the greatest difference at the highest workload (352 ± 22 vs. 492 ± 48 ml/min, HFrEF vs. control, 45% MVC). During KE exercise, MAP and CO increased similarly across work rates between groups. However, HFrEF patients exhibited a diminished leg hyperemic response across all work rates, with the most substantial decrement at the highest intensity (1,842 ± 64 vs. 2,675 ± 81 ml/min; HFrEF vs. control, 15 W). Together, these findings indicate a marked attenuation in exercising limb perfusion attributable to impairments in peripheral vasodilatory capacity during both arm and leg exercise in patients with HFrEF, which likely plays a role in limiting exercise capacity in this patient population. PMID:25260608

A contralateral repeated bout effect attenuates induction of NF-κB DNA binding following eccentric exercise.

PubMed

Xin, Ling; Hyldahl, Robert D; Chipkin, Stuart R; Clarkson, Priscilla M

2014-06-01

We investigated the existence of contralateral repeated bout effect and tested if the attenuation of nuclear factor-kappa B (NF-κB; an important regulator of muscle inflammation) induction following eccentric exercise is a potential mechanism. Thirty-one healthy men performed two bouts of knee extension eccentric exercise, initially with one leg and then with the opposite leg 4 wk later. Vastus lateralis muscle biopsies of both exercised and control legs were taken 3 h postexercise. Knee extension isometric and isokinetic strength (60°/sec and 180°/sec) were measured at baseline, pre-exercise, immediately postexercise, and 1/day for 5 days postexercise. Serum creatine kinase (CK) activity and muscle soreness were assessed at baseline and 1/day for 5 days postexercise. NF-κB (p65) DNA-binding activity was measured in the muscle biopsies. Isometric strength loss was lower in bout 2 than in bout 1 at 24, 72, and 96 h postexercise (P < 0.05). Isokinetic strength (60°/s and 180°/s) was reduced less in bout 2 than in bout 1 at 72 h postexercise (P < 0.01). There were no significant differences between bouts for postexercise CK activity or muscle soreness. p65 DNA-binding activity was increased following eccentric exercise (compared with the control leg) in bout 1 (122.9% ± 2.6%; P < 0.001) and bout 2 (109.1% ± 3.0%; P < 0.05). Compared with bout 1, the increase in NF-κB DNA-binding activity postexercise was attenuated after bout 2 (P = 0.0008). Repeated eccentric exercise results in a contralateral repeated bout effect, which could be due to the attenuated increase in NF-κB activity postexercise. Copyright © 2014 the American Physiological Society.

Acute effects of repeated bouts of aerobic exercise on arterial stiffness after glucose ingestion.

PubMed

Kobayashi, Ryota; Hashimoto, Yuto; Hatakeyama, Hiroyuki; Okamoto, Takanobu

2018-03-22

The aim of this study was to investigate the acute repeated bouts of aerobic exercise decrease leg arterial stiffness. However, the influence of repeated bouts of aerobic exercise on arterial stiffness after glucose ingestion is unknown. The present study investigates the acute effects of repeated bouts of aerobic exercise on arterial stiffness after the 75-g oral glucose tolerance test (OGTT). Ten healthy young men (age, 23.2 ± 0.9 years) performed repeated bouts of aerobic exercise trial (RE, 65% peak oxygen uptake; two 15 min bouts of cycling performed 20 min apart) and control trial (CON, seated and resting in a quiet room) at 80 min before the 75-g OGTT on separate days in a randomized, controlled crossover fashion. Carotid-femoral (aortic) and femoral-ankle (leg) pulse wave velocity, carotid augmentation index, brachial and ankle blood pressure, heart rate and blood glucose and insulin levels were measured before (baseline) and 30, 60 and 120 min after the 75-g OGTT. Leg pulse wave velocity, ankle systolic blood pressure and blood glucose levels increased from baseline after the 75-g OGTT in the CON trial, but not in the RE trial. The present findings indicate that acute repeated bouts of aerobic exercise before glucose ingestion suppress increases in leg arterial stiffness following glucose ingestion. RE trial repeated bouts of aerobic exercise trial; CON trial control trial; BG blood glucose; VO 2peak peak oxygen uptake; PWV Pulse wave velocity; AIx carotid augmentation index; BP blood pressure; HR heart rate; CVs coefficients of variation; RPE Ratings of perceived exertion; SE standard error.

Leg extensor muscle strength, postural stability, and fear of falling after a 2-month home exercise program in women with severe knee joint osteoarthritis.

PubMed

Rätsepsoo, Monika; Gapeyeva, Helena; Sokk, Jelena; Ereline, Jaan; Haviko, Tiit; Pääsuke, Mati

2013-01-01

BACKGROUND AND OBJECTIVE. The aim of this study was to compare the leg extensor muscle strength, the postural stability, and the fear of falling in the women with severe knee joint osteoarthritis (OA) before and after a 2-month home exercise program (HEP). MATERIAL AND METHODS. In total, 17 women aged 46-72 years with late-stage knee joint OA scheduled for total knee arthroplasty participated in this study before and after the 2-month HEP with strengthening, stretching, balance, and step exercises. The isometric peak torque (PT) of the leg extensors and postural stability characteristics when standing on a firm or a foam surface for 30 seconds were recorded. The fear of falling and the pain intensity (VAS) were estimated. RESULTS. A significant increase in the PT and the PT-to-body weight (PT-to-BW) ratio of the involved leg as well as the bilateral PT and the PT-to-BW ratio was found after the 2-month HEP compared with the data before the HEP (P<0.05). The PT and the PT-to-BW ratio of the involved leg were significantly lower compared with the uninvolved leg before the HEP (P<0.05). The center of the pressure sway length (foam surface) decreased significantly after the HEP (P<0.05). Significant correlations were found between the PT of the involved leg and the bilateral PT and the fear of falling and between the PT of the involved leg and the postural sway (foam surface) before the HEP. CONCLUSIONS. After the 2-month HEP, the leg extensor muscle strength increased and the postural sway length on a foam surface decreased. The results indicate that the increased leg extensor muscle strength improves postural stability and diminishes the fear of falling in women with late-stage knee joint OA.

Brachial artery vasodilatation during prolonged lower limb exercise: role of shear rate

PubMed Central

Padilla, Jaume; Simmons, Grant H.; Vianna, Lauro C.; Davis, Michael J.; Laughlin, M. Harold; Fadel, Paul J.

2012-01-01

We recently observed a marked increase in brachial artery (BA) diameter during prolonged leg cycling exercise. The purpose of the present study was to test the hypothesis that this increase in BA diameter during lower limb exercise is shear stress mediated. Accordingly, we determined whether recapitulation of cycling-induced BA shear rate with forearm heating, a known stimulus evoking shear-induced conduit artery dilatation, would elicit comparable profiles and magnitudes of BA vasodilatation to those observed during cycling. In 12 healthy men, BA diameter and blood velocity were measured simultaneously using Doppler ultrasonography at baseline and every 5 min during 60 min of either steady-state semi-recumbent leg cycling (120 W) or forearm heating. At the onset of cycling, the BA diameter was reduced (−3.9 ± 1.2% at 5 min; P < 0.05), but it subsequently increased throughout the remainder of the exercise bout (+15.1 ± 1.6% at 60 min; P < 0.05). The increase in BA diameter during exercise was accompanied by an approximately 2.5-fold rise in BA mean shear rate (P < 0.05). Similar increases in BA mean shear with forearm heating elicited an equivalent magnitude of BA vasodilatation to that observed during cycling (P > 0.05). Herein, we found that in the absence of exercise the extent of the BA vasodilator response was reproduced when the BA was exposed to comparable magnitudes of shear rate via forearm heating. These results are consistent with the hypothesis that shear stress plays a key role in signalling brachial artery vasodilatation during dynamic leg exercise. PMID:21784788

The effect of age and unilateral leg immobilization for 2 weeks on substrate utilization during moderate-intensity exercise in human skeletal muscle.

PubMed

Vigelsø, A; Gram, M; Dybboe, R; Kuhlman, A B; Prats, C; Greenhaff, P L; Constantin-Teodosiu, D; Birk, J B; Wojtaszewski, J F P; Dela, F; Helge, J W

2016-04-15

This study aimed to provide molecular insight into the differential effects of age and physical inactivity on the regulation of substrate metabolism during moderate-intensity exercise. Using the arteriovenous balance technique, we studied the effect of immobilization of one leg for 2 weeks on leg substrate utilization in young and older men during two-legged dynamic knee-extensor moderate-intensity exercise, as well as changes in key proteins in muscle metabolism before and after exercise. Age and immobilization did not affect relative carbohydrate and fat utilization during exercise, but the older men had higher uptake of exogenous fatty acids, whereas the young men relied more on endogenous fatty acids during exercise. Using a combined whole-leg and molecular approach, we provide evidence that both age and physical inactivity result in intramuscular lipid accumulation, but this occurs only in part through the same mechanisms. Age and inactivity have been associated with intramuscular triglyceride (IMTG) accumulation. Here, we attempt to disentangle these factors by studying the effect of 2 weeks of unilateral leg immobilization on substrate utilization across the legs during moderate-intensity exercise in young (n = 17; 23 ± 1 years old) and older men (n = 15; 68 ± 1 years old), while the contralateral leg served as the control. After immobilization, the participants performed two-legged isolated knee-extensor exercise at 20 ± 1 W (∼50% maximal work capacity) for 45 min with catheters inserted in the brachial artery and both femoral veins. Biopsy samples obtained from vastus lateralis muscles of both legs before and after exercise were used for analysis of substrates, protein content and enzyme activities. During exercise, leg substrate utilization (respiratory quotient) did not differ between groups or legs. Leg fatty acid uptake was greater in older than in young men, and although young men demonstrated net leg glycerol release during exercise, older men showed net glycerol uptake. At baseline, IMTG, muscle pyruvate dehydrogenase complex activity and the protein content of adipose triglyceride lipase, acetyl-CoA carboxylase 2 and AMP-activated protein kinase (AMPK)γ3 were higher in young than in older men. Furthermore, adipose triglyceride lipase, plasma membrane-associated fatty acid binding protein and AMPKγ3 subunit protein contents were lower and IMTG was higher in the immobilized than the contralateral leg in young and older men. Thus, immobilization and age did not affect substrate choice (respiratory quotient) during moderate exercise, but the whole-leg and molecular differences in fatty acid mobilization could explain the age- and immobilization-induced IMTG accumulation. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

The effect of age and unilateral leg immobilization for 2 weeks on substrate utilization during moderate‐intensity exercise in human skeletal muscle

PubMed Central

Gram, M.; Dybboe, R.; Kuhlman, A. B.; Prats, C.; Greenhaff, P. L.; Constantin‐Teodosiu, D.; Birk, J. B.; Wojtaszewski, J. F. P.; Dela, F.; Helge, J. W.

2016-01-01

Key points This study aimed to provide molecular insight into the differential effects of age and physical inactivity on the regulation of substrate metabolism during moderate‐intensity exercise.Using the arteriovenous balance technique, we studied the effect of immobilization of one leg for 2 weeks on leg substrate utilization in young and older men during two‐legged dynamic knee‐extensor moderate‐intensity exercise, as well as changes in key proteins in muscle metabolism before and after exercise.Age and immobilization did not affect relative carbohydrate and fat utilization during exercise, but the older men had higher uptake of exogenous fatty acids, whereas the young men relied more on endogenous fatty acids during exercise.Using a combined whole‐leg and molecular approach, we provide evidence that both age and physical inactivity result in intramuscular lipid accumulation, but this occurs only in part through the same mechanisms. Abstract Age and inactivity have been associated with intramuscular triglyceride (IMTG) accumulation. Here, we attempt to disentangle these factors by studying the effect of 2 weeks of unilateral leg immobilization on substrate utilization across the legs during moderate‐intensity exercise in young (n = 17; 23 ± 1 years old) and older men (n = 15; 68 ± 1 years old), while the contralateral leg served as the control. After immobilization, the participants performed two‐legged isolated knee‐extensor exercise at 20 ± 1 W (∼50% maximal work capacity) for 45 min with catheters inserted in the brachial artery and both femoral veins. Biopsy samples obtained from vastus lateralis muscles of both legs before and after exercise were used for analysis of substrates, protein content and enzyme activities. During exercise, leg substrate utilization (respiratory quotient) did not differ between groups or legs. Leg fatty acid uptake was greater in older than in young men, and although young men demonstrated net leg glycerol release during exercise, older men showed net glycerol uptake. At baseline, IMTG, muscle pyruvate dehydrogenase complex activity and the protein content of adipose triglyceride lipase, acetyl‐CoA carboxylase 2 and AMP‐activated protein kinase (AMPK)γ3 were higher in young than in older men. Furthermore, adipose triglyceride lipase, plasma membrane‐associated fatty acid binding protein and AMPKγ3 subunit protein contents were lower and IMTG was higher in the immobilized than the contralateral leg in young and older men. Thus, immobilization and age did not affect substrate choice (respiratory quotient) during moderate exercise, but the whole‐leg and molecular differences in fatty acid mobilization could explain the age‐ and immobilization‐induced IMTG accumulation. PMID:26801521

Prior exercise and standing as strategies to circumvent sitting-induced leg endothelial dysfunction.

PubMed

Morishima, Takuma; Restaino, Robert M; Walsh, Lauren K; Kanaley, Jill A; Padilla, Jaume

2017-06-01

We have previously shown that local heating or leg fidgeting can prevent prolonged sitting-induced leg endothelial dysfunction. However, whether physical activity prevents subsequent sitting-induced leg endothelial dysfunction remains unknown. Herein, we tested the hypothesis that sitting-induced leg endothelial dysfunction would be prevented by prior exercise. We also examined if, in the absence of exercise, standing is an effective alternative strategy to sitting for conserving leg endothelial function. Fifteen young healthy subjects completed three randomized experimental trials: (1) sitting without prior exercise; (2) sitting with prior exercise; and (3) standing without prior exercise. Following baseline popliteal artery flow-mediated dilation (FMD) measurements, subjects maintained a supine position for 45 min in the sitting and standing trials, without prior exercise, or performed 45 min of leg cycling before sitting (i.e. sitting with prior exercise trial). Thereafter, subjects were positioned into a seated or standing position, according to the trial, for 3 h. Popliteal artery FMD measures were then repeated. Three hours of sitting without prior exercise caused a significant impairment in popliteal artery FMD (baseline: 3.8±0.5%, post-sitting: 1.5±0.5%, P <0.05), which was prevented when sitting was preceded by a bout of cycling exercise (baseline: 3.8±0.5%, post-sitting: 3.6±0.7%, P >0.05). Three hours of standing did not significantly alter popliteal artery FMD (baseline: 4.1±0.4%, post-standing: 4.3±0.4%, P >0.05). In conclusion, prolonged sitting-induced leg endothelial dysfunction can be prevented by prior aerobic exercise. In addition, in the absence of exercise, standing represents an effective substitute to sitting for preserving leg conduit artery endothelial function. © 2017 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

Optimum frequency of exercise for bone health: randomised controlled trial of a high-impact unilateral intervention.

PubMed

Bailey, Christine A; Brooke-Wavell, Katherine

2010-04-01

Exercise can increase bone strength, but to be effective in reducing fracture risk, exercise must be feasible enough to be adopted into daily life and influence potentially vulnerable skeletal sites such as the superolateral cortex of the femoral neck, where thinning is associated with increased fracture risk. Brief, high-impact exercise increases femoral neck bone density but the optimal frequency of such exercise and the location of bone accrual is unknown. This study thus examined (1) the effectiveness of different weekly frequencies of exercise on femoral neck BMD and (2) whether BMD change differed between hip sites using a high-impact, unilateral intervention. Healthy premenopausal women were randomly assigned to exercise 0, 2, 4, or 7 days/week for 6 months. The exercise intervention incorporated 50 multidirectional hops on one randomly selected leg. BMD was measured by DXA at baseline and after 6 months of exercise. Changes in the exercise leg were compared between groups using ANCOVA, with change in the control leg and baseline BMD as covariates. RM-MANOVA was conducted to determine whether bone changes from exercise differed between hip sites. 61 women (age 33.6+/-11.1 years) completed the intervention. Compliance amongst exercisers was 86.7+/-10.6%. Peak ground reaction forces during exercise increased from 2.5 to 2.8 times body weight. The change in femoral neck BMD in the exercise limb (adjusted for change in the control limb and baseline BMD) differed between groups (p=0.015), being -0.3% (-1.2 to 0.6), 0.0% (-1.0 to 1.0), 0.9% (-0.1 to 2.0) and 1.8% (0.8 to 2.8) in those exercising 0, 2, 4 and 7 days per week, respectively. When BMD changes at upper neck, lower neck and trochanter were compared using RM-MANOVA, a significant exercise effect was observed (p=0.048), but this did not differ significantly between sites (p=0.439) despite greatest mean increases at the upper femoral neck. Brief, daily hopping exercises increased femoral neck BMD in premenopausal women but less frequent exercise was not effective. Brief high-impact exercise may have a role in reducing hip fragility, but may need to be performed frequently for optimal response. Copyright 2009 Elsevier Inc. All rights reserved.

Efficacy of Hip Strengthening Exercises Compared With Leg Strengthening Exercises on Knee Pain, Function, and Quality of Life in Patients With Knee Osteoarthritis.

PubMed

Lun, Victor; Marsh, Andrew; Bray, Robert; Lindsay, David; Wiley, Preston

2015-11-01

The purpose of this study was to compare the efficacy of hip and leg strengthening exercise programs on knee pain, function, and quality of life (QOL) of patients with knee osteoarthritis (KOA). Single-Blinded Randomized Clinical Trial. Patients with KOA. Male and female subjects were recruited from patients referred to the University of Calgary Sport Medicine Center and from newspaper advertisements. Thirty-seven and 35 patients with KOA were randomly assigned to either a 12-week hip or leg strengthening exercise program, respectively. Both exercise programs consisted of strengthening and flexibility exercises, which were completed 3 to 5 days a week. The first 3 weeks of exercise were supervised and the remaining 9 weeks consisted of at-home exercise. Knee Injury and Osteoarthritis Score (KOOS) and Western Ontario McMaster Arthritis Index (WOMAC) questionnaires, 6-minute walk test, hip and knee range of motion (ROM), and hip and leg muscle strength. Statistically and clinically significant improvements in the KOOS and WOMAC pain subscale scores were observed in both the hip and leg strengthening programs. There was no statistical difference in the change in scores observed between the 2 groups. Equal improvements in the KOOS and WOMAC function and QOL subscales were observed for both programs. There was no change in hip and knee ROM or hip and leg strength in either group. Isolated hip and leg strengthening exercise programs seem to similarly improve knee pain, function, and QOL in patients with KOA. The results of this study show that both hip and leg strengthening exercises improve pain and QOL in patients with KOA and should be incorporated into the exercise prescription of patients with KOA.

The Effect of Increasing Jump Steps on Stance Leg Joint Kinetics in Bounding.

PubMed

Kariyama, Yasushi; Hobara, Hiroaki; Zushi, Koji

2018-06-20

Jump distance per step in bounding exercises from the standing position increases with increasing number of steps. We examined the hypothesis that the joint kinetic variables of the stance leg would also increase accordingly. Eleven male athletes (sprinters and jumpers) performed bounding exercise, starting from the double-leg standing posture, and covered the longest distance possible by performing a series of seven forward alternating single-leg jumps. Kinematic and kinetic data were calculated using the data by a motion capture system and force platforms. Hip extension joint work were decreased at third step (1 st : 1.07±0.22, 3 rd : 0.45±0.15, 5 th : 0.47±0.14 J•kg -1 ; partial η 2 : 0.86), and hip abduction joint power were increased (1 st : 7.53±3.29, 3 rd : 13.50±4.44, 5 th : 21.37±9.93 W•kg -1 ; partial η 2 : 0.58); the knee extension joint power were increased until the third step (1 st : 14.43±4.94, 3 rd : 17.13±3.59, 5 th : 14.28±2.86 W•kg -1 ; partial η 2 : 0.29), and ankle plantar flexion joint power increased (1 st : 34.14±5.33, 3 rd : 37.46±4.45, 5 th : 40.11±5.66 W•kg -1 ; partial η 2 : 0.53). These results contrast with our hypothesis, and indicate that increasing the jump distance during bounding exercises is not necessarily accompanied by increases in joint kinetics of stance leg. Moreover, changes in joint kinetics vary at different joints and anatomical axes. © Georg Thieme Verlag KG Stuttgart · New York.

Low-Volume Intense Exercise Elicits Post-exercise Hypotension and Subsequent Hypervolemia, Irrespective of Which Limbs Are Exercised.

PubMed

Graham, Matthew J; Lucas, Samuel J E; Francois, Monique E; Stavrianeas, Stasinos; Parr, Evelyn B; Thomas, Kate N; Cotter, James D

2016-01-01

Exercise reduces arterial and central venous blood pressures during recovery, which contributes to its valuable anti-hypertensive effects and to facilitating hypervolemia. Repeated sprint exercise potently improves metabolic function, but its cardiovascular effects (esp. hematological) are less well-characterized, as are effects of exercising upper versus lower limbs. The purposes of this study were to identify the acute (<24 h) profiles of arterial blood pressure and blood volume for (i) sprint intervals versus endurance exercise, and (ii) sprint intervals using arms versus legs. Twelve untrained males completed three cycling exercise trials; 50-min endurance (legs), and 5(*)30-s intervals using legs or arms, in randomized and counterbalanced sequence, at a standardized time of day with at least 8 days between trials. Arterial pressure, hemoglobin concentration and hematocrit were measured before, during and across 22 h after exercise, the first 3 h of which were seated rest. The post-exercise hypotensive response was larger after leg intervals than endurance (AUC: 7540 ± 3853 vs. 3897 ± 2757 mm Hg·min, p = 0.049, 95% CI: 20 to 6764), whereas exercising different limbs elicited similar hypotension (arms: 6420 ± 3947 mm Hg·min, p = 0.48, CI: -1261 to 3896). In contrast, arterial pressure at 22 h was reduced after endurance but not after leg intervals (-8 ± 8 vs. 0 ± 7 mm Hg, p = 0.04, CI: 7 ± 7) or reliably after arm intervals (-4 ± 8 mm Hg, p = 0.18 vs. leg intervals). Regardless, plasma volume expansion at 22 h was similar between leg intervals and endurance (both +5 ± 5%; CI: -5 to 5%) and between leg and arm intervals (arms: +5 ± 7%, CI: -8 to 5%). These results emphasize the relative importance of central and/or systemic factors in post-exercise hypotension, and indicate that markedly diverse exercise profiles can induce substantive hypotension and subsequent hypervolemia. At least for endurance exercise, this hypervolemia may not depend on the volume of post-exercise hypotension. Finally, endurance exercise led to reduced blood pressure the following day, but sprint interval exercise did not.

The Effect of Pilates Exercise on Trunk and Postural Stability and Throwing Velocity in College Baseball Pitchers: Single Subject Design

PubMed Central

Howe, Katherine

2007-01-01

Background Baseball pitchers need trunk strength to maximize performance. The Pilates method of exercise is gaining popularity throughout the country as a fitness and rehabilitation method of exercise. However, very few studies exist that examine the effects of the Pilates method of exercise on trunk strength or performance. Objectives Using a single subject, multiple baseline across subjects design, this study examines the effects of the Pilates method of exercise on performance of double leg lowering, star excursion balance test, and throwing velocity in college-aged baseball pitchers. Methods A convenience sample of three college baseball pitchers served as the subjects for this single subject design study. For each subject, double leg lowering, star excursion balance test, and throwing speed were measured prior to the introduction of the intervention. When baseline test values showed consistent performance, the intervention was introduced to one subject at a time. Intervention was introduced to the other subjects over a period of 4 weeks as they also demonstrated consistent performance on the baseline tests. Intervention was continued with periodic tests for the remainder of the 10 week trial. Results Each subject improved in performance on double leg lowering (increased 24.43-32.7%) and star excursion balance test (increased 4.63-17.84%) after introduction of the intervention. Throwing speed improved in two of the three subjects (up to 5.61%). Discussion and Conclusions The Pilates method of exercise may contribute to improved performance in double leg lowering, star excursion balance tests, and throwing speed in college baseball pitchers. PMID:21522199

The measurement of peripheral blood volume reactions to tilt test by the electrical impedance technique after exercise in athletes

NASA Astrophysics Data System (ADS)

Melnikov, A. A.; Popov, S. G.; Nikolaev, D. V.; Vikulov, A. D.

2013-04-01

We have investigated the distribution of peripheral blood volumes in different regions of the body in response to the tilt-test in endurance trained athletes after aerobic exercise. Distribution of peripheral blood volumes (ml/beat) simultaneously in six regions of the body (two legs, two hands, abdomen, neck and ECG) was assessed in response to the tilt-test using the impedance method (the impedance change rate (dZ/dT). Before and after exercise session cardiac stroke (CSV) and blood volumes in legs, arms and neck were higher in athletes both in lying and standing positions. Before exercise the increase of heart rate and the decrease of a neck blood volume in response to tilting was lower (p <0.05) but the decrease of leg blood volumes was higher (p<0.001) in athletes. The reactions in arms and abdomen blood volumes were similar. Also, the neck blood volumes as percentage of CSV (%/CSV) did not change in the control but increased in athletes (p <0.05) in response to the tilt test. After (10 min recovery) the aerobic bicycle exercise (mean HR = 156±8 beat/min, duration 30 min) blood volumes in neck and arms in response to the tilting were reduced equally, but abdomen (p<0.05) and leg blood volumes (p <0.001) were lowered more significantly in athletes. The neck blood flow (%/CSV) did not change in athletes but decreased in control (p<0.01), which was offset by higher tachycardia in response to tilt-test in controls after exercise. The data demonstrate greater orthostatic tolerance in athletes both before and after exercise during fatigue which is due to effective distribution of blood flows aimed at maintaining cerebral blood flow.

Effect of Exercise Intensity on Percent Body Fat Determined by Leg-to-Leg and Segmental Bioelectrical Impedance Analyses in Adults

ERIC Educational Resources Information Center

Andreacci, Joseph L.; Nagle, Trisha; Fitzgerald, Elise; Rawson, Eric S.; Dixon, Curt B.

2013-01-01

Purpose: We examined the impact that cycle ergometry exercise had on percent body fat (%BF) estimates when assessed using either leg-to-leg or segmental bioelectrical impedance analysis (LBIA; SBIA) and whether the intensity of the exercise bout impacts the %BF magnitude of change. Method: Seventy-four college-aged adults participated in this…

Development of exercise-induced arm-leg blood pressure gradient and abnormal arterial compliance in patients with repaired coarctation of the aorta.

PubMed

Markham, Larry W; Knecht, Sandra K; Daniels, Stephen R; Mays, Wayne A; Khoury, Philip R; Knilans, Timothy K

2004-11-01

Often, the lack of systemic arterial hypertension and the lack of a resting arm-leg blood pressure gradient are used to assess the adequacy of the anatomic result after intervention for coarctation of the aorta (CoA). Some patients with no arm-leg gradient at rest may develop a gradient with exercise, leading caregivers to question the success of the repair. It is not clear what the prevalence is of patients who have undergone a successful intervention for CoA and have no arm-leg gradient at rest but develop a significant gradient with exercise and which factors may predict the development of an arm-leg gradient with exercise. This study evaluates the prevalence and predictors of an exercise-induced arm-leg gradient in subjects who have undergone an apparently successful intervention for CoA.

Effects of low-level laser therapy applied before or after plyometric exercise on muscle damage markers: randomized, double-blind, placebo-controlled trial.

PubMed

Fritsch, Carolina Gassen; Dornelles, Maurício Pinto; Severo-Silveira, Lucas; Marques, Vanessa Bernardes; Rosso, Isabele de Albuquerque; Baroni, Bruno Manfredini

2016-12-01

Promising effects of phototherapy on markers of exercise-induced muscle damage has been already demonstrated in constant load or isokinetic protocols. However, its effects on more functional situations, such as plyometric exercises, and when is the best moment to apply this treatment (pre- or post-exercise) remain unclear. Therefore, the purpose of this study was to investigate the effect of low-level laser therapy (LLLT) before or after plyometric exercise on quadriceps muscle damage markers. A randomized, double-blinded, placebo-controlled trial was conducted with 24 healthy men, 12 at pre-exercise treatment group and 12 at post-exercise treatment group. Placebo and LLLT (810 nm, 200 mW per diode, 6 J per diode, 240 J per leg) were randomly applied on right/left knee extensor muscles of each volunteer before/after a plyometric exercise protocol. Muscular echo intensity (ultrasonography images), soreness (visual analogue scale - VAS), and strength impairment (maximal voluntary contraction - MVC) were assessed at baseline, 24, 48, and 72 h post-exercise. Legs treated with LLLT before or after exercise presented significantly smaller increments of echo intensity (values up to 1 %) compared to placebo treatments (increased up to ∼7 %). No significant treatment effect was found for VAS and MVC, although a trend toward better results on LLLT legs have been found for VAS (mean values up to 30 % lesser than placebo leg). In conclusion, LLLT applied before or after plyometric exercise reduces the muscle echo intensity response and possibly attenuates the muscle soreness. However, these positive results were not observed on strength impairment.

Effects of exercise continued until anaerobic threshold on balance performance in male basketball players.

PubMed

Erkmen, Nurtekin; Suveren, Sibel; Göktepe, Ahmet Salim

2012-06-01

The objective of the present study was to determine the effects of exercise continued until the anaerobic threshold on balance performance in basketball players. Twelve male basketball players (age = 20.92 ± 2.81 years, body height = 192.72 ± 7.61 cm, body mass = 88.09 ± 8.41 kg, training experience = 7.17 ± 3.10 years) volunteered to participate in this study. A Kinesthetic Ability Trainer (KAT 2000 stabilometer) was used to measure the balance performance. Balance tests consisted of static tests on dominant, nondominant and double leg stance. The Bruce Protocol was performed by means of a treadmill. The exercise protocol was terminated when the subject passed the anaerobic threshold. After the exercise protocol, balance measurements were immediately repeated. Statistical differences between pre and post-exercise for dominant, nondominant and double leg stance were determined by the paired samples t-test according to the results of the test of normality. The post-exercise balance score on the dominant leg was significantly higher than pre-exercise (t = -2.758, p < 0.05). No differences existed between pre- and post-exercise in the balance scores of the nondominant leg after the exercise protocol (t = 0.428, p > 0.05). A significant difference was found between pre and post-exercise balance scores in the double leg stance (t = -2.354, p < 0.05). The main finding of this study was that an incremental exercise continued until the anaerobic threshold decreased balance performance on the dominant leg in basketball players, but did not alter it in the nondominant leg.

Limb symmetry during double-leg squats and single-leg squats on land and in water in adults with long-standing unilateral anterior knee pain; a cross sectional study.

PubMed

Severin, Anna C; Burkett, Brendan J; McKean, Mark R; Wiegand, Aaron N; Sayers, Mark G L

2017-01-01

The presence of pain during movement typically results in changes in technique. However, the physical properties of water, such as flotation, means that water-based exercise may not only reduce compensatory movement patterns but also allow pain sufferers to complete exercises that they are unable to perform on land. The purpose of this study was to assess bilateral kinematics during double-leg squats and single-leg squats on land and in water in individuals with unilateral anterior knee pain. A secondary aim was to quantify bilateral asymmetry in both environments in affected and unaffected individuals using a symmetry index. Twenty individuals with unilateral knee pain and twenty healthy, matched controls performed body weight double- and single-leg squats in both environments while inertial sensors (100 Hz) recorded trunk and lower body kinematics. Repeated-measures statistics tested for environmental effects on movement depths and peak angles within the anterior knee pain group. Differences in their inter-limb symmetry in each environments was compared to the control group using analysis of variance tests. Water immersion allowed for greater movement depths during both exercises (double-leg squat: +7 cm, p  = 0.032, single-leg squat: +9 cm, p  = 0.002) for the knee pain group. The double-leg squat was symmetrical on land but water immersion revealed asymmetries in the lower body frontal plane movements. The single-leg squat revealed decreased hip flexion and frontal plane shank motions on the affected limb in both environments. Water immersion also affected the degree of lower limb asymmetry in both groups, with differences also showing between groups. Individuals with anterior knee pain achieved increased squat depth during both exercises whilst in water. Kinematic differences between the affected and unaffected limbs were often increased in water. Individuals with unilateral anterior knee pain appear to utilise different kinematics in the affected and unaffected limb in both environments.

Four weeks one-leg training and high fat diet does not alter PPARalpha protein or mRNA expression in human skeletal muscle.

PubMed

Helge, J W; Bentley, D; Schjerling, P; Willer, M; Gibala, M J; Franch, J; Tapia-Laliena, M A; Daugaard, J R; Andersen, J L

2007-09-01

Fatty acid metabolism is influenced by training and diet with exercise training mediating this through activation of nuclear hormone receptor peroxisome proliferator-activated receptor alpha (PPARalpha) in skeletal muscle. This study investigated the effect of training and high fat or normal diet on PPARalpha expression in human skeletal muscle. Thirteen men trained one leg (T) four weeks (31.5 h in total), while the other leg (UT) served as control. During the 4 weeks six subjects consumed high fat (FAT) diet and seven subjects maintained a normal (CHO) diet. Biopsies were obtained from vastus lateralis muscle in both legs before and after training. After the biopsy, one-leg extension exercise was performed in random order with both legs 30 min at 95% of workload max. A training effect was evident as citrate synthase activity increased (P < 0.05) by 15% in the trained, but not the control leg in both groups. During exercise respiratory exchange ratio was lower in FAT (0.86 +/- 0.01, 0.83 +/- 0.01, mean +/- SEM) than CHO (0.96 +/- 0.02, 0.94 +/- 0.03) and in UT than T legs, respectively. The PPARalpha protein (144 +/- 44, 104 +/- 28, 79 +/- 15, 79 +/- 14, % of pre level) and PPARalpha mRNA (69 +/- [2, 2], 78 +/- [7, 6], 92 +/- [22, 18], 106 +/- [21, 18], % of pre level, geometric mean +/- SEM) expression remained unchanged by diet and training in FAT (UT, T) and CHO (UT, T), respectively. After the training and diet CS, HAD, PPARalpha, UCP2, UCP3 and mFABP mRNA content remained unchanged, whereas GLUT4 mRNA was lower in both groups and LDHA mRNA was lower (P < 0.05) only in FAT. 4 weeks one leg knee extensor training did not affect PPARalpha protein or mRNA expression. Furthermore, higher fat oxidation during exercise after fat rich diet was not accompanied by an increased PPARalpha protein or mRNA expression after 4 weeks.

No differential effects of divergent isocaloric supplements on signaling for muscle protein turnover during recovery from muscle-damaging eccentric exercise.

PubMed

Rahbek, Stine Klejs; Farup, Jean; de Paoli, Frank; Vissing, Kristian

2015-04-01

Unaccustomed high-intensity eccentric exercise (ECC) can provoke muscle damage including several days of muscle force loss. Post-exercise dietary supplementation may provide a strategy to accelerate rate of force regain by affecting mechanisms related to muscle protein turnover. The aim of the current study was to investigate if protein signaling mechanisms involved in muscle protein turnover would be differentially affected by supplementation with either whey protein hydrolysate and carbohydrate (WPH+CHO) versus isocaloric carbohydrate (CHO) after muscle-damaging ECC. Twenty-four young healthy participants received either WPH+CHO (n = 12) or CHO supplements (n = 12) during post-exercise recovery from 150 maximal unilateral eccentric contractions. Prior to, at 3 h and at 24, 48, 96 and/or 168 h post-exercise, muscle strength, muscle soreness, and Akt-mTOR and FOXO signaling proteins, were measured in an ECC exercising leg and in the contralateral non-exercise control leg (CON). After ECC, muscle force decreased by 23-27 % at 24 h post-exercise, which was followed by gradual, although not full recovery at 168 h post-exercise, with no differences between supplement groups. Phosphorylation of mTOR, p70S6K and rpS6 increased and phosphorylation of FOXO1 and FOXO3 decreased in the ECC leg, with no differences between supplement groups. Phosphorylation changes were also observed for rpS6, FOXO1 and FOXO3a in the CON leg, suggesting occurrence of remote tissue effects. In conclusion, divergent dietary supplementation types did not produce differences in signaling for muscle turnover during recovery from muscle-damaging exercise.

Intramuscular pressures in antigravity muscles using gravity-independent, pneumatic hardware.

PubMed

Macias, Brandon R; Minocha, Ranjeet; Cutuk, Adnan A; Hill, James; Shiau, Jonathon; Hargens, Alan R

2008-08-01

Resistive exercise helps prevent muscle atrophy in microgravity, but better exercise equipment is needed. Therefore, the purpose of this study was to determine if a pneumatic, gravity-independent leg-press device (LPD) provides sufficient force to leg musculature. We hypothesized that intramuscular pressure (IMP), a quantitative index of muscle force, is greater in the antigravity superficial posterior and deep posterior compartments than in the non-antigravity anterior compartment during bilateral leg-press exercise. Millar pressure transducers were inserted into the anterior, lateral, superficial posterior, and deep posterior muscle compartments of the left leg of eight healthy subjects (three women, five men). Subjects were supine on the Keiser SX-1, a pneumatic LPD. Then maximal voluntary contraction (MVC) was determined; each subject performed three consecutive voluntary contractions at approximately 18%, 50%, and 100% MVC while continuously measuring IMP. Repeated measures ANOVA were used to determine differences of IMPs between compartments and loads. The magnitudes of IMP (mean +/- SEM) at 18 - 3% (abbreviated approximately 18%), 50%, and 100% MVC in the superficial and deep posterior compartments were significantly greater than that in the anterior compartment during exercise (P < 0.05). Additionally, IMPs in all four compartments significantly rose as resistance increased at approximately 18%, 50%, and 100% MVC (P < 0.05). The LPD provides significantly increased resistance to all four compartments, but with greater loading of the antigravity compartments as compared to the non-antigravity compartment. Since antigravity muscles of the leg are contained primarily in the superficial and deep posterior compartments, the LPD may help prevent muscle atrophy associated with microgravity.

The Interaction of Fatigue and Potentiation Following an Acute Bout of Unilateral Squats

PubMed Central

Andrews, Samantha K.; Horodyski, Jesse M.; MacLeod, Daniel A.; Whitten, Joseph; Behm, David G.

2016-01-01

A prior conditioning resistance exercise can augment subsequent performance of the affected muscles due to the effects of post-activation potentiation (PAP). The non-local muscle fatigue literature has illustrated the global neural effects of unilateral fatigue. However, no studies have examined the possibility of acute non-local performance enhancements. The objective of the study was to provide a conditioning stimulus in an attempt to potentiate the subsequent jump performance of the affected limb and determine if there were performance changes in the contralateral limb. Using a randomized allocation, 14 subjects (6 females, 8 males) completed three conditions on separate days: 1) unilateral, dominant leg, Bulgarian split squat protocol with testing of the exercised leg, 2) unilateral, dominant leg, Bulgarian split squat protocol with testing of the contralateral, non-exercised leg and 3) control session with testing of the non-dominant leg. Pre- and post-testing consisted of countermovement (CMJ) and drop jumps (DJ). The exercised leg exhibited CMJ height increases of 3.5% (p = 0.008; d = 0.28), 4.0% (p = 0.011; d = 0.33) and 3.2% (p = 0.013; d = 0.26) at 1, 5, and 10 min post-intervention respectively. The contralateral CMJ height had 2.0% (p = 0.034; d = 0.18), 1.2% (p = 0.2; d = 0.12), and 2.1% (p = 0.05; d = 0.17) deficits at 1, 5, and 10 min post-intervention respectively. Similar relative results were found for CMJ power. There were no significant interactions for DJ measures or control CMJ measures. The findings suggest that PAP effects were likely predominant for the exercised leg whereas the conditioning exercise provided trivial magnitude although statistically significant neural impairments for the contralateral limb. Key points Post-activation potentiation of unilateral CMJ height was achieved following 5 sequential squats at 50% 1RM, 2 squats at 70% 1RM, 1 squat at 90% 1RM with 3 min rest periods. The conditioning exercises did not elicit significant drop jump improvements, likely due to balance challenges. In contrast to the potentiation of the affected leg, there were statistically significant impairments of contralateral CMJ height suggesting the co-existence of post-activation potentiation (affected limb) and crossover neural fatigue. PMID:27928208

Haemodynamic responses to dehydration in the resting and exercising human leg.

PubMed

Pearson, James; Kalsi, Kameljit K; Stöhr, Eric J; Low, David A; Barker, Horace; Ali, Leena; González-Alonso, José

2013-06-01

Dehydration and hyperthermia reduces leg blood flow (LBF), cardiac output ([Formula: see text]) and arterial pressure during whole-body exercise. It is unknown whether the reductions in blood flow are associated with dehydration-induced alterations in arterial blood oxygen content (C aO2) and O2-dependent signalling. This study investigated the impact of dehydration and concomitant alterations in C aO2 upon LBF and [Formula: see text]. Haemodynamics, arterial and femoral venous blood parameters and plasma [ATP] were measured at rest and during one-legged knee-extensor exercise in 7 males in four conditions: (1) control, (2) mild dehydration, (3) moderate dehydration, and (4) rehydration. Relative to control, C aO2 and LBF increased with dehydration at rest and during exercise (C aO2: from 199 ± 1 to 208 ± 2, and 202 ± 2 to 210 ± 2 ml L(-1) and LBF: from 0.38 ± 0.04 to 0.77 ± 0.09, and 1.64 ± 0.09 to 1.88 ± 0.1 L min(-1), respectively). Similarly, [Formula: see text] was unchanged or increased with dehydration at rest and during exercise, whereas arterial and leg perfusion pressures declined. Following rehydration, C aO2 declined (to 193 ± 2 mL L(-1)) but LBF remained elevated. Alterations in LBF were unrelated to C aO2 (r (2) = 0.13-0.27, P = 0.48-0.64) and plasma [ATP]. These findings suggest dehydration and concomitant alterations in C aO2 do not compromise LBF despite reductions in plasma [ATP]. While an additive or synergistic effect cannot be excluded, reductions in LBF during exercise with dehydration may not necessarily be associated with alterations in C aO2 and/or intravascular [ATP].

Creatine supplementation prevents acute strength loss induced by concurrent exercise.

PubMed

de Salles Painelli, Vítor; Alves, Victor Tavares; Ugrinowitsch, Carlos; Benatti, Fabiana Braga; Artioli, Guilherme Giannini; Lancha, Antonio Herbert; Gualano, Bruno; Roschel, Hamilton

2014-08-01

To investigate the effect of creatine (CR) supplementation on the acute interference induced by aerobic exercise on subsequent maximum dynamic strength (1RM) and strength endurance (SE, total number of repetitions) performance. Thirty-two recreationally strength-trained men were submitted to a graded exercise test to determine maximal oxygen consumption (VO2max: 41.56 ± 5.24 ml kg(-1) min(-1)), anaerobic threshold velocity (ATv: 8.3 ± 1.18 km h(-1)), and baseline performance (control) on the 1RM and SE (4 × 80 % 1RM to failure) tests. After the control tests, participants were randomly assigned to either a CR (20 g day(-1) for 7 days followed by 5 g day(-1) throughout the study) or a placebo (PL-dextrose) group, and then completed 4 experimental sessions, consisting of a 5-km run on a treadmill either continuously (90 % ATv) or intermittently (1:1 min at vVO2max) followed by either a leg- or bench-press SE/1RM test. CR was able to maintain the leg-press SE performance after the intermittent aerobic exercise when compared with C (p > 0.05). On the other hand, the PL group showed a significant decrease in leg-press SE (p ≤ 0.05). CR supplementation significantly increased bench-press SE after both aerobic exercise modes, while the bench-press SE was not affected by either mode of aerobic exercise in the PL group. Although small increases in 1RM were observed after either continuous (bench press and leg press) or intermittent (bench press) aerobic exercise in the CR group, they were within the range of variability of the measurement. The PL group only maintained their 1RM. In conclusion, the acute interference effect on strength performance observed in concurrent exercise may be counteracted by CR supplementation.

Influence of exercise modality on cardiac parasympathetic and sympathetic indices during post-exercise recovery.

PubMed

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

2018-02-12

This study investigated indirect measures of post-exercise parasympathetic reactivation (using heart-rate-variability, HRV) and sympathetic withdrawal (using systolic-time-intervals, STI) following upper- and lower-body exercise. Randomized, counter-balanced, crossover. 13 males (age 26.4±4.7years) performed maximal arm-cranking (MAX-ARM) and leg-cycling (MAX-LEG). Subsequently, participants undertook separate 8-min bouts of submaximal HR-matched exercise of each mode (ARM and LEG). HRV (including natural-logarithm of root-mean-square-of-successive-differences, Ln-RMSSD) and STI (including pre-ejection-period, PEP) were assessed throughout 10-min seated recovery. Peak-HR was higher (p=0.001) during MAX-LEG (182±7beatsmin -1 ) compared with MAX-ARM (171±12beatsmin -1 ), while HR (p<0.001) and Ln-RMSSD (p=0.010) recovered more rapidly following MAX-ARM. PEP recovery was similar between maximal bouts (p=0.106). HR during submaximal exercise was 146±7 (LEG) and 144±8beatsmin -1 (LEG) (p=0.139). Recovery of HR and Ln-RMSSD was also similar between submaximal modalities, remaining below baseline throughout recovery (p<0.001). PEP was similar during submaximal exercise (LEG 70±6ms; ARM 72±9ms; p=0.471) although recovery was slower following ARM (p=0.021), with differences apparent from 1- to 10-min recovery (p≤0.036). By 10-min post-exercise, PEP recovered to baseline (132±21ms) following LEG (130±21ms; p=0.143), but not ARM (121±17ms; p=0.001). Compared with submaximal lower-body exercise, HR-matched upper-body exercise elicited a similar recovery of HR and HRV indices of parasympathetic reactivation, but delayed recovery of PEP (reflecting sympathetic withdrawal). Exercise modality appears to influence post-exercise parasympathetic reactivation and sympathetic withdrawal in an intensity-dependent manner. These results highlight the need for test standardization and may be relevant to multi-discipline athletes and in clinical applications with varying modes of exercise testing. Copyright © 2018 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Maximal muscular vascular conductances during whole body upright exercise in humans

PubMed Central

Calbet, J A L; Jensen-Urstad, M; van Hall, G; Holmberg, H -C; Rosdahl, H; Saltin, B

2004-01-01

That muscular blood flow may reach 2.5 l kg−1 min−1 in the quadriceps muscle has led to the suggestion that muscular vascular conductance must be restrained during whole body exercise to avoid hypotension. The main aim of this study was to determine the maximal arm and leg muscle vascular conductances (VC) during leg and arm exercise, to find out if the maximal muscular vasodilatory response is restrained during maximal combined arm and leg exercise. Six Swedish elite cross-country skiers, age (mean ± s.e.m.) 24 ± 2 years, height 180 ± 2 cm, weight 74 ± 2 kg, and maximal oxygen uptake (V̇O2,max) 5.1 ± 0.1 l min−1 participated in the study. Femoral and subclavian vein blood flows, intra-arterial blood pressure, cardiac output, as well as blood gases in the femoral and subclavian vein, right atrium and femoral artery were determined during skiing (roller skis) at ∼76% of V̇O2,max and at V̇O2,max with different techniques: diagonal stride (combined arm and leg exercise), double poling (predominantly arm exercise) and leg skiing (predominantly leg exercise). During submaximal exercise cardiac output (26–27 l min−1), mean blood pressure (MAP) (∼87 mmHg), systemic VC, systemic oxygen delivery and pulmonary V̇O2 (∼4 l min−1) attained similar values regardless of exercise mode. The distribution of cardiac output was modified depending on the musculature engaged in the exercise. There was a close relationship between VC and V̇O2 in arms (r = 0.99, P < 0.001) and legs (r = 0.98, P < 0.05). Peak arm VC (63.7 ± 5.6 ml min−1 mmHg−1) was attained during double poling, while peak leg VC was reached at maximal exercise with the diagonal technique (109.8 ± 11.5 ml min−1 mmHg−1) when arm VC was 38.8 ± 5.7 ml min−1 mmHg−1. If during maximal exercise arms and legs had been vasodilated to the observed maximal levels then mean arterial pressure would have dropped at least to 75–77 mmHg in our experimental conditions. It is concluded that skeletal muscle vascular conductance is restrained during whole body exercise in the upright position to avoid hypotension. PMID:15121799

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.

Muscle sympathetic nerve responses to passive and active one-legged cycling: insights into the contributions of central command.

PubMed

Doherty, Connor J; Incognito, Anthony V; Notay, Karambir; Burns, Matthew J; Slysz, Joshua T; Seed, Jeremy D; Nardone, Massimo; Burr, Jamie F; Millar, Philip J

2018-01-01

The contribution of central command to the peripheral vasoconstrictor response during exercise has been investigated using primarily handgrip exercise. The purpose of the present study was to compare muscle sympathetic nerve activity (MSNA) responses during passive (involuntary) and active (voluntary) zero-load cycling to gain insights into the effects of central command on sympathetic outflow during dynamic exercise. Hemodynamic measurements and contralateral leg MSNA (microneurography) data were collected in 18 young healthy participants at rest and during 2 min of passive and active zero-load one-legged cycling. Arterial baroreflex control of MSNA burst occurrence and burst area were calculated separately in the time domain. Blood pressure and stroke volume increased during exercise ( P < 0.0001) but were not different between passive and active cycling ( P > 0.05). In contrast, heart rate, cardiac output, and total vascular conductance were greater during the first and second minute of active cycling ( P < 0.001). MSNA burst frequency and incidence decreased during passive and active cycling ( P < 0.0001), but no differences were detected between exercise modes ( P > 0.05). Reductions in total MSNA were attenuated during the first ( P < 0.0001) and second ( P = 0.0004) minute of active compared with passive cycling, in concert with increased MSNA burst amplitude ( P = 0.02 and P = 0.005, respectively). The sensitivity of arterial baroreflex control of MSNA burst occurrence was lower during active than passive cycling ( P = 0.01), while control of MSNA burst strength was unchanged ( P > 0.05). These results suggest that central feedforward mechanisms are involved primarily in modulating the strength, but not the occurrence, of a sympathetic burst during low-intensity dynamic leg exercise. NEW & NOTEWORTHY Muscle sympathetic nerve activity burst frequency decreased equally during passive and active cycling, but reductions in total muscle sympathetic nerve activity were attenuated during active cycling. These results suggest that central command primarily regulates the strength, not the occurrence, of a muscle sympathetic burst during low-intensity dynamic leg exercise.

Exercise metabolism in human skeletal muscle exposed to prior eccentric exercise

PubMed Central

Asp, Sven; Daugaard, Jens R; Kristiansen, Søren; Kiens, Bente; Richter, Erik A

1998-01-01

The effects of unaccustomed eccentric exercise on exercise metabolism during a subsequent bout of graded concentric exercise were investigated in seven healthy male subjects. Arterial and bilateral femoral venous catheters were inserted 2 days after eccentric exercise of one thigh (eccentric thigh) and blood samples were taken before and during graded two-legged concentric knee-extensor exercise. Muscle biopsies were obtained from the eccentric and control vastus lateralis before (rest) and after (post) the concentric exercise bout. Maximal knee-extensor concentric exercise capacity was decreased by an average of 23 % (P < 0.05) in the eccentric compared with the control thigh. The resting muscle glycogen content was lower in the eccentric thigh than in the control thigh (402 ± 30 mmol (kg dry wt)−1vs. 515 ± 26 mmol (kg dry wt)−1, means ± s.e.m., P < 0.05), and following the two-legged concentric exercise this difference substantially increased (190 ± 46 mmol (kg dry wt)−1vs. 379 ± 58 mmol (kg dry wt)−1, P < 0.05) despite identical power and duration of exercise with the two thighs. There was no measurable difference in glucose uptake between the eccentric and control thigh before or during the graded two-legged concentric exercise. Lactate release was higher from the eccentric thigh at rest and, just before termination of the exercise bout, release of lactate decreased from this thigh (suggesting decreased glycogenolysis), whereas no decrease was found from the contralateral control thigh. Lower glycerol release from the eccentric thigh during the first, lighter part of the exercise (P < 0.05) suggested impaired triacylglycerol breakdown. At rest, sarcolemmal GLUT4 glucose transporter content and glucose transport were similar in the two thighs, and concentric exercise increased sarcolemmal GLUT4 content and glucose transport capacity similarly in the two thighs. It is concluded that in muscle exposed to prior eccentric contractions, exercise at a given power output requires a higher relative workload than in undamaged muscle. This increases utilization of the decreased muscle glycogen stores, contributing to decreased endurance. PMID:9547403

Analysis of the Hamstring Muscle Activation During two Injury Prevention Exercises

PubMed Central

Monajati, Alireza; Larumbe-Zabala, Eneko; Goss-Sampson, Mark

2017-01-01

Abstract The aim of this study was to perform an electromyographic and kinetic comparison of two commonly used hamstring eccentric strengthening exercises: Nordic Curl and Ball Leg Curl. After determining the maximum isometric voluntary contraction of the knee flexors, ten female athletes performed 3 repetitions of both the Nordic Curl and Ball Leg Curl, while knee angular displacement and electromyografic activity of the biceps femoris and semitendinosus were monitored. No significant differences were found between biceps femoris and semitendinosus activation in both the Nordic Curl and Ball Leg Curl. However, comparisons between exercises revealed higher activation of both the biceps femoris (74.8 ± 20 vs 50.3 ± 25.7%, p = 0.03 d = 0.53) and semitendinosus (78.3 ± 27.5 vs 44.3 ± 26.6%, p = 0.012, d = 0.63) at the closest knee angles in the Nordic Curl vs Ball Leg Curl, respectively. Hamstring muscles activation during the Nordic Curl increased, remained high (>70%) between 60 to 40° of the knee angle and then decreased to 27% of the maximal isometric voluntary contraction at the end of movement. Overall, the biceps femoris and semitendinosus showed similar patterns of activation. In conclusion, even though the hamstring muscle activation at open knee positions was similar between exercises, the Nordic Curl elicited a higher hamstring activity compared to the Ball Leg Curl. PMID:29339983

Nutrition Coupled with High-Load Traditional or Low-Load Blood Flow Restricted Exercise During Human Limb Suspension

NASA Technical Reports Server (NTRS)

Hackney, K. J.; Everett, M.; Ploutz-Snyder, L. L.

2011-01-01

High-load resistance exercise (HRE) and low-load blood flow restricted (BFR) exercise have demonstrated efficacy for attenuating unloading related muscle atrophy and dysfunction. In recreational exercisers, protein consumption immediately before and/or after exercise has been shown to increase the skeletal muscle anabolic response to resistance training. PURPOSE: To compare the skeletal muscle adaptations when chocolate milk intake was coupled with HRE or low-load BFR exercise [3 d/wk] during simulated lower limb weightlessness. METHODS: Eleven subjects were counterbalanced [based on age and gender] to HRE (31 +/- 14 yr, 170 +/- 13 cm, 71 +/- 18 kg, 2M/3W) or low-load BFR exercise (31 +/- 12 yr, 169 +/- 13 cm, 66 +/- 14 kg, 2M/4W) during 30 days of unilateral lower limb suspension (ULLS). Both HRE and BFR completed 3 sets of single leg press and calf raise exercise during ULLS. BFR exercise intensity was 20% of repetition maximum (1RM) with a cuff inflation pressure of 1.3 systolic blood pressure (143 4 mmHg). Cuff pressure was maintained during all 3 sets including rest intervals (90s). HRE intensity was 75% 1RM and was performed without cuff inflation. Immediately (<10 min) before and after exercise 8 fl oz of chocolate milk (150 kcal, 2.5g total fat, 22g total carbohydrate, 8g protein) was consumed to optimize acute exercise responses in favor of muscle anabolism. ULLS analog compliance was assessed from leg skin temperature recordings and plantar accelerometry. Muscle cross-sectional area (CSA) for knee extensor and plantar flexor muscle groups were determined from analysis of magnetic resonance images using ImageJ software. 1RM strength for leg press and calf raise was assessed on the Agaton exercise system. Muscular endurance during leg press and calf raise was evaluated from the maximal number of repetitions performed to volitional fatigue using 40% of pre-ULLS 1RM. RESULTS: Steps detected by plantar acceleometry declined by 98.9% during ULLS relative to an ambulatory control period. Average skin temperature of the unloaded calf declined from 27.4 C to 26.8 C (-2.1%), while there was a slight increase (+1.1%) in skin temperature in the loaded calf (27.6 C to 27.9 C). Collectively, these measures indicate strong subject compliance with the ULLS analog. Unloaded limb work performed during leg press (1514 +/- 334 vs. 576 +/- 103) and calf raise (2886 +/- 508 vs. 1233 +/- 153) exercises sessions was greater in HRE vs. BFR, respectively. Leg press training loads were 44 +/- 7 kg in HRE compared to 11 +/- 1 kg in BFR. Similarly, calf raise training loads were 81 +/- 11 kg in HRE and 16 +/- 1 kg in BFR. Pre to post-ULLS training adaptations in the unloaded leg are shown in the table. CONCLUSION: The preliminary results of this investigation suggest when HRE is optimized for muscle anabolism during unloading muscle size and strength are preserved (or enhanced) at the expense of muscle endurance. In contrast, when BFR exercise is optimized for muscle anabolism during unloading muscle endurance is preserved (or enhanced) at the expense of muscle size and strength

The effects of two methods of reflexology and stretching exercises on the severity of restless leg syndrome among hemodialysis patients.

PubMed

Shahgholian, Nahid; Jazi, Shahrzad Khojandi; Karimian, Jahangir; Valiani, Mahboubeh

2016-01-01

Restless leg syndrome prevalence is high among the patients undergoing hemodialysis. Due to several side effects of medicational treatments, the patients prefer non-medicational methods. Therefore, the present study aimed to investigate the effects of two methods of reflexology and stretching exercises on the severity of restless leg syndrome among patients undergoing hemodialysis. This study is a randomized clinical trial that was done on 90 qualified patients undergoing hemodialysis in selected hospitals of Isfahan, who were diagnosed with restless leg syndrome through standard restless leg syndrome questionnaire. They were randomly assigned by random number table to three groups: Reflexology, stretching exercises, and control groups through random allocation. Foot reflexology and stretching exercises were conducted three times a week for 30-40 min within straight 4 weeks. Data analysis was performed by SPSS version 18 using descriptive and inferential statistical analyses [one-way analysis of variance (ANOVA), paired t-test, and least significant difference (LSD) post hoc test]. There was a significant difference in the mean scores of restless leg syndrome severity between reflexology and stretching exercises groups, compared to control (P < 0.001), but there was no significant difference between the two study groups (P < 0.001). Changes in the mean score of restless leg syndrome severity were significantly higher in reflexology and stretching exercises groups compared to the control group (P < 0.001), but it showed no significant difference between reflexology massage and stretching exercises groups. Our obtained results showed that reflexology and stretching exercises can reduce the severity of restless leg syndrome. These two methods of treatment are recommended to the patients.

The effects of two methods of reflexology and stretching exercises on the severity of restless leg syndrome among hemodialysis patients

PubMed Central

Shahgholian, Nahid; Jazi, Shahrzad Khojandi; Karimian, Jahangir; Valiani, Mahboubeh

2016-01-01

Background: Restless leg syndrome prevalence is high among the patients undergoing hemodialysis. Due to several side effects of medicational treatments, the patients prefer non-medicational methods. Therefore, the present study aimed to investigate the effects of two methods of reflexology and stretching exercises on the severity of restless leg syndrome among patients undergoing hemodialysis. Materials and Methods: This study is a randomized clinical trial that was done on 90 qualified patients undergoing hemodialysis in selected hospitals of Isfahan, who were diagnosed with restless leg syndrome through standard restless leg syndrome questionnaire. They were randomly assigned by random number table to three groups: Reflexology, stretching exercises, and control groups through random allocation. Foot reflexology and stretching exercises were conducted three times a week for 30–40 min within straight 4 weeks. Data analysis was performed by SPSS version 18 using descriptive and inferential statistical analyses [one-way analysis of variance (ANOVA), paired t-test, and least significant difference (LSD) post hoc test]. Results: There was a significant difference in the mean scores of restless leg syndrome severity between reflexology and stretching exercises groups, compared to control (P < 0.001), but there was no significant difference between the two study groups (P < 0.001). Changes in the mean score of restless leg syndrome severity were significantly higher in reflexology and stretching exercises groups compared to the control group (P < 0.001), but it showed no significant difference between reflexology massage and stretching exercises groups. Conclusions: Our obtained results showed that reflexology and stretching exercises can reduce the severity of restless leg syndrome. These two methods of treatment are recommended to the patients. PMID:27186197

Hemodynamic Changes in Rat Leg Muscles during Tourniquet-induced Ischemia-reperfusion Injury Observed by Near-infrared Spectroscopy

DTIC Science & Technology

2009-07-01

leg muscle during pressure increase (Arbabi et al 1999) and in the human leg muscle during exercise (Breit et al 1997, Egun et al 2002, van den Brand...time of flight measurement. Phys Med Biol 1988;33:1433–42. [PubMed: 3237772] Egun A, Farooq V, Torella F, Cowley R, Thorniley MS, McCollum CN. The

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.

Voluntary enhanced cocontraction of hamstring muscles during open kinetic chain leg extension exercise: its potential unloading effect on the anterior cruciate ligament.

PubMed

Biscarini, Andrea; Benvenuti, Paolo; Botti, Fabio M; Brunetti, Antonella; Brunetti, Orazio; Pettorossi, Vito E

2014-09-01

A number of research studies provide evidence that hamstring cocontraction during open kinetic chain knee extension exercises enhances tibiofemoral (TF) stability and reduces the strain on the anterior cruciate ligament. To determine the possible increase in hamstring muscle coactivation caused by a voluntary cocontraction effort during open kinetic chain leg-extension exercises, and to assess whether an intentional hamstring cocontraction can completely suppress the anterior TF shear force during these exercises. Descriptive laboratory study. Knee kinematics as well as electromyographic activity in the semitendinosus (ST), semimembranosus (SM), biceps femoris (BF), and quadriceps femoris muscles were measured in 20 healthy men during isotonic leg extension exercises with resistance (R) ranging from 10% to 80% of the 1-repetition maximum (1RM). The same exercises were also performed while the participants attempted to enhance hamstring coactivation through a voluntary cocontraction effort. The data served as input parameters for a model to calculate the shear and compressive TF forces in leg extension exercises for any set of coactivation patterns of the different hamstring muscles. For R≤ 40% 1RM, the peak coactivation levels obtained with intentional cocontraction (l) were significantly higher (P < 10(-3)) than those obtained without intentional cocontraction (l 0). For each hamstring muscle, maximum level l was reached at R = 30% 1RM, corresponding to 9.2%, 10.5%, and 24.5% maximum voluntary isometric contraction (MVIC) for the BF, ST, and SM, respectively, whereas the ratio l/l 0 reached its maximum at R = 20% 1RM and was approximately 2, 3, and 4 for the BF, SM, and ST, respectively. The voluntary enhanced coactivation level l obtained for R≤ 30% 1RM completely suppressed the anterior TF shear force developed by the quadriceps during the exercise. In leg extension exercises with resistance R≤ 40% 1RM, coactivation of the BF, SM, and ST can be significantly enhanced (up to 2, 3, and 4 times, respectively) by a voluntary hamstring cocontraction effort. The enhanced coactivation levels obtained for R≤ 30% 1RM can completely suppress the anterior TF shear force developed by the quadriceps during the exercise. This laboratory study suggests that leg extension exercise with intentional hamstring cocontraction may have the potential to be a safe and effective quadriceps-strengthening intervention in the early stages of rehabilitation programs for anterior cruciate ligament injury or reconstruction recovery. Further studies, including clinical trials, are needed to investigate the relevance of this therapeutic exercise in clinical practice. © 2014 The Author(s).

Systolic and Diastolic Left Ventricular Mechanics during and after Resistance Exercise.

PubMed

Stöhr, Eric J; Stembridge, Mike; Shave, Rob; Samuel, T Jake; Stone, Keeron; Esformes, Joseph I

2017-10-01

To improve the current understanding of the impact of resistance exercise on the heart, by examining the acute responses of left ventricular (LV) strain, twist, and untwisting rate ("LV mechanics"). LV echocardiographic images were recorded in systole and diastole before, during and immediately after (7-12 s) double-leg press exercise at two intensities (30% and 60% of maximum strength, one-repetition maximum). Speckle tracking analysis generated LV strain, twist, and untwisting rate data. Additionally, beat-by-beat blood pressure was recorded and systemic vascular resistance (SVR) and LV wall stress were calculated. Responses in both exercise trials were statistically similar (P > 0.05). During effort, stroke volume decreased, whereas SVR and LV wall stress increased (P < 0.05). Immediately after effort, stroke volume returned to baseline, whereas SVR and wall stress decreased (P < 0.05). Similarly, acute exercise was accompanied by a significant decrease in systolic parameters of LV muscle mechanics (P < 0.05). However, diastolic parameters, including LV untwisting rate, were statistically unaltered (P > 0.05). Immediately after exercise, systolic LV mechanics returned to baseline levels (P < 0.05) but LV untwisting rate increased significantly (P < 0.05). A single, acute bout of double-leg press resistance exercise transiently reduces systolic LV mechanics, but increases diastolic mechanics after exercise, suggesting that resistance exercise has a differential impact on systolic and diastolic heart muscle function. The findings may explain why acute resistance exercise has been associated with reduced stroke volume but chronic exercise training may result in increased LV volumes.

The susceptibility of the knee extensors to eccentric exercise-induced muscle damage is not affected by leg dominance but by exercise order.

PubMed

Hody, S; Rogister, B; Leprince, P; Laglaine, T; Croisier, J-L

2013-09-01

The aims of this study were first to compare the response of dominant and non-dominant legs to eccentric exercise and second, to examine whether there is an effect of exercise order on the magnitude of symptoms associated with intense eccentric protocols. Eighteen young men performed three sets of 30 maximal eccentric isokinetic (60° s(-1)) contractions of the knee extensors (range of motion, ROM: 0°-100°, 0 = full extension) using either dominant or non-dominant leg. They repeated a similar eccentric bout using the contralateral leg 6 weeks later. The sequence of leg's use was allocated to create equally balanced groups. Four indirect markers of muscle damage including subjective pain intensity, maximal isometric strength, muscle stiffness and plasma creatine kinase (CK) activity were measured before and 24 h after exercise. All markers changed significantly following the eccentric bout performed either by dominant or non-dominant legs, but no significant difference was observed between legs. Interestingly, the comparison between the first and second eccentric bouts revealed that muscle soreness (-42%, P<0.001), CK activity (-62%, P<0.05) and strength loss (-54%, P<0.01) were significantly lower after the second bout. This study suggests that leg dominance does not influence the magnitude of exercise-induced muscle damage and supports for the first time the existence of a contralateral protection against exercise-induced muscle damage in the lower limbs. © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

A Behavioral Mechanism of How Increases in Leg Strength Improve Old Adults’ Gait Speed

PubMed Central

Uematsu, Azusa; Tsuchiya, Kazushi; Kadono, Norio; Kobayashi, Hirofumi; Kaetsu, Takamasa; Hortobágyi, Tibor; Suzuki, Shuji

2014-01-01

We examined a behavioral mechanism of how increases in leg strength improve healthy old adults’ gait speed. Leg press strength training improved maximal leg press load 40% (p = 0.001) and isometric strength in 5 group of leg muscles 32% (p = 0.001) in a randomly allocated intervention group of healthy old adults (age 74, n = 15) but not in no-exercise control group (age 74, n = 8). Gait speed increased similarly in the training (9.9%) and control (8.6%) groups (time main effect, p = 0.001). However, in the training group only, in line with the concept of biomechanical plasticity of aging gait, hip extensors and ankle plantarflexors became the only significant predictors of self-selected and maximal gait speed. The study provides the first behavioral evidence regarding a mechanism of how increases in leg strength improve healthy old adults’ gait speed. PMID:25310220

Tart cherry concentrate does not enhance muscle protein synthesis response to exercise and protein in healthy older men.

PubMed

Jackman, Sarah R; Brook, Matthew S; Pulsford, Richard M; Cockcroft, Emma J; Campbell, Matthew I; Rankin, Debbie; Atherton, Philip; Smith, Kenneth; Bowtell, Joanna L

2018-06-08

Oxidative stress and inflammation may contribute to anabolic resistance in response to protein and exercise in older adults. We investigated whether consumption of montmorency cherry concentrate (MCC) increased anabolic sensitivity to protein ingestion and resistance exercise in healthy older men. Sixteen healthy older men were randomized to receive MCC (60 mL·d -1 ) or placebo (PLA) for two weeks, after baseline measures in week 1. During week 3, participants consumed 10 g whey protein·d -1 and completed three bouts of unilateral leg resistance exercise (4 × 8-10 repetitions at 80% 1RM). Participants consumed a bolus (150 mL) and weekly (50 mL) doses of deuterated water. Body water 2 H enrichment was measured in saliva and vastus lateralis biopsies were taken from the non-exercised leg after weeks 1, 2 and 3, and the exercised leg after week 3, to measure tracer incorporation at rest, in response to protein and protein + exercise. Myofibrillar protein synthesis increased in response to exercise + protein compared to rest (p < 0.05) in both groups, but there was no added effect of supplement (MCC: 1.79 ± 0.75 EX vs 1.15 ± 0.40 rest; PLA: 2.22 ± 0.54 vs 1.21 ± 0.18; all %·d -1 ). Muscle total NFĸB protein was decreased with exercise and protein in MCC (NFĸB: -20.7 ± 17.5%) but increased in PLA (NFĸB: 17.8 ± 31.3%, p = 0.073). Short-term MCC ingestion does not affect the anabolic response to protein and exercise in healthy, relatively active, older men, despite MCC ingestion attenuating expression of proteins involved in the muscle inflammatory response to exercise, which may influence the chronic training response. Copyright © 2018 Elsevier Inc. All rights reserved.

Sensitivity of sensor-based sit-to-stand peak power to the effects of training leg strength, leg power and balance in older adults.

PubMed

Regterschot, G Ruben H; Folkersma, Marjanne; Zhang, Wei; Baldus, Heribert; Stevens, Martin; Zijlstra, Wiebren

2014-01-01

Increasing leg strength, leg power and overall balance can improve mobility and reduce fall risk. Sensor-based assessment of peak power during the sit-to-stand (STS) transfer may be useful for detecting changes in mobility and fall risk. Therefore, this study investigated whether sensor-based STS peak power and related measures are sensitive to the effects of increasing leg strength, leg power and overall balance in older adults. A further aim was to compare sensitivity between sensor-based STS measures and standard clinical measures of leg strength, leg power, balance, mobility and fall risk, following an exercise-based intervention. To achieve these aims, 26 older adults (age: 70-84 years) participated in an eight-week exercise program aimed at improving leg strength, leg power and balance. Before and after the intervention, performance on normal and fast STS transfers was evaluated with a hybrid motion sensor worn on the hip. In addition, standard clinical tests (isometric quadriceps strength, Timed Up and Go test, Berg Balance Scale) were performed. Standard clinical tests as well as sensor-based measures of peak power, maximal velocity and duration of normal and fast STS showed significant improvements. Sensor-based measurement of peak power, maximal velocity and duration of normal STS demonstrated a higher sensitivity (absolute standardized response mean (SRM): ≥ 0.69) to the effects of training leg strength, leg power and balance than standard clinical measures (absolute SRM: ≤ 0.61). Therefore, the presented sensor-based method appears to be useful for detecting changes in mobility and fall risk. Copyright © 2013 Elsevier B.V. All rights reserved.

Changes in executive function after acute bouts of passive cycling in Parkinson's disease.

PubMed

Ridgel, Angela L; Kim, Chul-Ho; Fickes, Emily J; Muller, Matthew D; Alberts, Jay L

2011-04-01

Individuals with Parkinson's disease (PD) often experience cognitive declines. Although pharmacologic therapies are helpful in treating motor deficits in PD, they do not appear to be effective for cognitive complications. Acute bouts of moderate aerobic exercise have been shown to improve cognitive function in healthy adults. However, individuals with PD often have difficulty with exercise. This study examined the effects of passive leg cycling on executive function in PD. Executive function was assessed with Trail-Making Test (TMT) A and B before and after passive leg cycling. Significant improvements on the TMT-B test occurred after passive leg cycling. Furthermore, the difference between times to complete the TMT-B and TMT-A significantly decreased from precycling to postcycling. Improved executive function after passive cycling may be a result of increases in cerebral blood flow. These findings suggest that passive exercise could be a concurrent therapy for cognitive decline in PD.

Effects of respiratory muscle work on respiratory and locomotor blood flow during exercise.

PubMed

Dominelli, Paolo B; Archiza, Bruno; Ramsook, Andrew H; Mitchell, Reid A; Peters, Carli M; Molgat-Seon, Yannick; Henderson, William R; Koehle, Michael S; Boushel, Robert; Sheel, A William

2017-11-01

What is the central question of this study? Does manipulation of the work of breathing during high-intensity exercise alter respiratory and locomotor muscle blood flow? What is the main finding and its importance? We found that when the work of breathing was reduced during exercise, respiratory muscle blood flow decreased, while locomotor muscle blood flow increased. Conversely, when the work of breathing was increased, respiratory muscle blood flow increased, while locomotor muscle blood flow decreased. Our findings support the theory of a competitive relationship between locomotor and respiratory muscles during intense exercise. Manipulation of the work of breathing (WOB) during near-maximal exercise influences leg blood flow, but the effects on respiratory muscle blood flow are equivocal. We sought to assess leg and respiratory muscle blood flow simultaneously during intense exercise while manipulating WOB. Our hypotheses were as follows: (i) increasing the WOB would increase respiratory muscle blood flow and decrease leg blood flow; and (ii) decreasing the WOB would decrease respiratory muscle blood flow and increase leg blood flow. Eight healthy subjects (n = 5 men, n = 3 women) performed a maximal cycle test (day 1) and a series of constant-load exercise trials at 90% of peak work rate (day 2). On day 2, WOB was assessed with oesophageal balloon catheters and was increased (via resistors), decreased (via proportional assist ventilation) or unchanged (control) during the trials. Blood flow was assessed using near-infrared spectroscopy optodes placed over quadriceps and the sternocleidomastoid muscles, coupled with a venous Indocyanine Green dye injection. Changes in WOB were significantly and positively related to changes in respiratory muscle blood flow (r = 0.73), whereby increasing the WOB increased blood flow. Conversely, changes in WOB were significantly and inversely related to changes in locomotor blood flow (r = 0.57), whereby decreasing the WOB increased locomotor blood flow. Oxygen uptake was not different during the control and resistor trials (3.8 ± 0.9 versus 3.7 ± 0.8 l min -1 , P > 0.05), but was lower on the proportional assist ventilator trial (3.4 ± 0.7 l min -1 , P < 0.05) compared with control. Our findings support the concept that respiratory muscle work significantly influences the distribution of blood flow to both respiratory and locomotor muscles. © 2017 The Authors. Experimental Physiology © 2017 The Physiological Society.

Arm mechanical efficiency and arm exercise capacity are relatively preserved in chronic obstructive pulmonary disease.

PubMed

Franssen, Frits M E; Wouters, Emiel F M; Baarends, Erica M; Akkermans, Marco A; Schols, Annemie M W J

2002-10-01

Previous studies indicate that energy expenditure related to physical activity is enhanced and that mechanical efficiency of leg exercise is reduced in patients with chronic obstructive pulmonary disease (COPD). However, it is yet unclear whether an inefficient energy expenditure is also present during other activities in COPD. This study was carried out to examine arm efficiency and peak arm exercise performance relative to leg exercise in 33 (23 male) patients with COPD ((mean +/- SEM) age: 61 +/- 2 yr; FEV : 40 +/- 2% of predicted) and 20 sex- and age-matched healthy controls. Body composition, pulmonary function, resting energy expenditure (REE), and peak leg and arm exercise performance were determined. To calculate mechanical efficiency, subjects performed submaximal leg and arm ergometry at 50% of achieved peak loads. During exercise testing, metabolic and ventilatory parameters were measured. In contrast to a reduced leg mechanical efficiency in patients compared with controls (15.6 +/- 0.6% and 22.5 +/- 0.6%, respectively; < 0.001), arm mechanical efficiency was comparable in both groups (COPD: 18.3 +/- 0.9%, controls: 21.0 +/- 1.2%; NS). Arm efficiency was not related to leg efficiency, pulmonary function, work of breathing, or REE. Also, arm exercise capacity was relatively preserved in patients with COPD (ratio arm peak work rate/leg peak work rate in patients: 89% vs 53% in controls; < 0.001). Mechanical efficiency and exercise capacity of the upper and lower limbs are not homogeneously affected in COPD, with a relative preservation of the upper limbs. This may have implications for screening of exercise tolerance and prescription of training interventions in patients with COPD. Future studies need to elucidate the mechanism behind this observation.

Pronounced effects of acute endurance exercise on gene expression in resting and exercising human skeletal muscle.

PubMed

Catoire, Milène; Mensink, Marco; Boekschoten, Mark V; Hangelbroek, Roland; Müller, Michael; Schrauwen, Patrick; Kersten, Sander

2012-01-01

Regular physical activity positively influences whole body energy metabolism and substrate handling in exercising muscle. While it is recognized that the effects of exercise extend beyond exercising muscle, it is unclear to what extent exercise impacts non-exercising muscles. Here we investigated the effects of an acute endurance exercise bouts on gene expression in exercising and non-exercising human muscle. To that end, 12 male subjects aged 44-56 performed one hour of one-legged cycling at 50% W(max). Muscle biopsies were taken from the exercising and non-exercising leg before and immediately after exercise and analyzed by microarray. One-legged cycling raised plasma lactate, free fatty acids, cortisol, noradrenalin, and adrenalin levels. Surprisingly, acute endurance exercise not only caused pronounced gene expression changes in exercising muscle but also in non-exercising muscle. In the exercising leg the three most highly induced genes were all part of the NR4A family. Remarkably, many genes induced in non-exercising muscle were PPAR targets or related to PPAR signalling, including PDK4, ANGPTL4 and SLC22A5. Pathway analysis confirmed this finding. In conclusion, our data indicate that acute endurance exercise elicits pronounced changes in gene expression in non-exercising muscle, which are likely mediated by changes in circulating factors such as free fatty acids. The study points to a major influence of exercise beyond the contracting muscle.

EXERCISES THAT FACILITATE OPTIMAL HAMSTRING AND QUADRICEPS CO-ACTIVATION TO HELP DECREASE ACL INJURY RISK IN HEALTHY FEMALES: A SYSTEMATIC REVIEW OF THE LITERATURE.

PubMed Central

Dedinsky, Rachel; Baker, Lindsey; Imbus, Samuel; Bowman, Melissa

2017-01-01

Background Anterior cruciate ligament (ACL) injury is common among females due to many anatomic, hormonal, and neuromuscular risk factors. One modifiable risk factor that places females at increased risk of ACL injury is a poor hamstrings: quadriceps (H:Q) co-activation ratio, which should be 0.6 or greater in order to decrease the stress placed on the ACL. Exercises that produce more quadriceps dominant muscle activation can add to the tension placed upon the ACL, potentially increasing the risk of ACL injury. Hypothesis/Purpose The purpose of this systematic review was to compare quadriceps and hamstring muscle activation during common closed kinetic chain therapeutic exercises in healthy female knees to determine what exercises are able to produce adequate H:Q co-activation ratios. Study Design Systematic Review Methods Multiple online databases were systematically searched and screened for inclusion. Eight articles were identified for inclusion. Data on mean electromyography (EMG) activation of both quadriceps and hamstring muscles, % maximal voluntary isometric contraction (MVIC), and H:Q co-activation ratios were extracted from the studies. Quality assessment was performed on all included studies. Results Exercises analyzed in the studies included variations of the double leg squat, variations of the single leg squat, lateral step-up, Fitter, Stairmaster® (Core Health and Fitness, Vancouver, WA), and slide board. All exercises, except the squat machine with posterior support at the level of the scapula and feet placed 50 cm in front of the hips, produced higher quadriceps muscle activation compared to hamstring muscle activation. Conclusion Overall, two leg squats demonstrate poor H:Q co-activation ratios. Single leg exercises, when performed between 30 and 90 degrees of knee flexion, produce adequate H:Q ratios, thereby potentially reducing the risk of tensile stress on the ACL and ACL injury. Level of Evidence 2a- Systematic Review of Cohort Studies PMID:28217412

An increase in prefrontal oxygenation at the start of voluntary cycling exercise was observed independently of exercise effort and muscle mass.

PubMed

Asahara, Ryota; Endo, Kana; Liang, Nan; Matsukawa, Kanji

2018-05-31

We have reported using near-infrared spectroscopy that an increase in prefrontal oxygenated-hemoglobin concentration (Oxy-Hb) at the start of cycling exercise has relation to central command, defined as a feedforward signal descending from higher brain centers. The final output of central command evokes the exercise effort-dependent cardiovascular responses. If the prefrontal cortex may output the final signal of central command toward the autonomic nervous system, the prefrontal oxygenation should increase depending on exercise effort. To test the hypothesis, we investigated the effects of exercise intensity and muscle mass on prefrontal oxygenation in 13 subjects. The subjects performed one- or two-legged cycling at various relative intensities for 1 min. The prefrontal Oxy-Hb and cardiovascular variables were simultaneously measured during exercise. The increase in cardiac output and the decrease in total peripheral resistance at the start of one- and two-legged cycling were augmented in proportion to exercise intensity and muscle mass recruitment. The prefrontal Oxy-Hb increased at the start of voluntary cycling, while such increase was not developed during passive cycling. Mental imagery of cycling also increased the prefrontal Oxy-Hb, concomitantly with peripheral muscle vasodilatation. However, the increase in prefrontal Oxy-Hb at the start of voluntary cycling seemed independent of exercise intensity and muscle mass recruitment. It is likely that the increased prefrontal activity at the start of cycling exercise is not representative of the final output signal of central command itself toward the autonomic nervous system but may trigger neuronal activity in the caudal brain responsible for the generation of central command.

Lifelong physical activity prevents an age-related reduction in arterial and skeletal muscle nitric oxide bioavailability in humans

PubMed Central

Nyberg, Michael; Blackwell, James R; Damsgaard, Rasmus; Jones, Andrew M; Hellsten, Ylva; Mortensen, Stefan P

2012-01-01

Ageing has been proposed to be associated with increased levels of reactive oxygen species (ROS) that scavenge nitric oxide (NO). In eight young sedentary (23 ± 1 years; Y), eight older lifelong sedentary (66 ± 2 years; OS) and eight older lifelong physically active subjects (62 ± 2 years; OA), we studied the effect of ROS on systemic and skeletal muscle NO bioavailability and leg blood flow by infusion of the antioxidant N-acetylcysteine (NAC). Infusion of NAC increased the bioavailability of NO in OS, as evidenced by an increased concentration of stable metabolites of NO (NOx) in the arterial and venous circulation and in the muscle interstitium. In OA, infusion of NAC only increased NOx concentrations in venous plasma whereas in Y, infusion of NAC did not affect NOx concentrations. Skeletal muscle protein levels of endothelial and neuronal NO synthase were 32% and 24% higher, respectively, in OA than in OS. Exercise at 12 W elicited a lower leg blood flow response that was associated with a lower leg oxygen uptake in OS than in Y. The improved bioavailability of NO in OS did not increase blood flow during exercise. These data demonstrate that NO bioavailability is compromised in the systemic circulation and in the musculature of sedentary ageing humans due to increased oxidative stress. Lifelong physical activity opposes this effect within the trained musculature and in the arterial circulation. The lower blood flow response to leg exercise in ageing humans is not associated with a reduced NO bioavailability. PMID:22890714

Athletes' leg pains.

PubMed Central

Orava, S.; Puranen, J.

1979-01-01

The frequency and nature of exertion pains of the leg in athletes were studied in 2,750 cases of overuse injuries treated at the Sports Clinic of the Deaconess Institute of Oulu, Finland, during the years 1972-1977. 465 cases of exertion pain (18%) were located in the shin. The medial tibial syndrome was the most common overuse injury among these athletes, comprising 9.5% of all exertion injuries and 60% of the leg exertion pains. Together with stress fracture of the tibia, the second most common exertion pain of the leg, it accounted for 75% of the total leg pains. There are certain difficulties in differentiating between the medial tibial syndrome and stress fracture of the tibia. They both occur at the same site with similar symptoms. Radiological examination and isotope scanning are needed. The medial tibial syndrome is an overuse injury at the medial tibial border caused by running exercises. The pain is elicited by exertional ischaemia. The pathogenesis is explained by increased pressure in the fascial compartment of the deep flexor muscles due to prolonged exercise. Similar chronic ischaemic pains from exercise are also found in other fascial compartments of the leg, especially in the anterior compartment. The only treatment needed for stress fractures is rest from training. Fascial compartment pains also usually subside. If chronic fascial syndromes prevent training, fasciotomy is recommended as a reliable method to restore the athlete to normal training without pains. PMID:486888

Esmolol acutely alters oxygen supply-demand balance in exercising muscles of healthy humans.

PubMed

Proctor, David N; Luck, J Carter; Maman, Stephan R; Leuenberger, Urs A; Muller, Matthew D

2018-04-01

Beta-adrenoreceptor antagonists (β blockers) reduce systemic O 2 delivery and blood pressure (BP) during exercise, but the subsequent effects on O 2 extraction within the active limb muscles are unknown. In this study, we examined the effects of the fast-acting, β 1 selective blocker esmolol on systemic hemodynamics and leg muscle O 2 saturation (near infrared spectroscopy, NIRS) during submaximal leg ergometry. Our main hypothesis was that esmolol would augment exercise-induced reductions in leg muscle O 2 saturation. Eight healthy adults (6 men, 2 women; 23-67 year) performed light and moderate intensity bouts of recumbent leg cycling before (PRE), during (β 1 -blocked), and 45 min following (POST) intravenous infusion of esmolol. Oxygen uptake, heart rate (HR), BP, and O 2 saturation (SmO 2 ) of the vastus lateralis (VL) and medial gastrocnemius (MG) muscles were measured continuously. Esmolol attenuated the increases in HR and systolic BP during light (-12 ± 9 bpm and -26 ± 12 mmHg vs. PRE) and moderate intensity (-20 ± 10 bpm and -40 ± 18 mmHg vs. PRE) cycling (all P < 0.01). Exercise-induced reductions in SmO 2 occurred to a greater extent during the β 1 -blockade trial in both the VL (P = 0.001 vs. PRE) and MG muscles (P = 0.022 vs. PRE). HR, SBP and SmO 2 were restored during POST (all P < 0.01 vs. β 1 -blocked). In conclusion, esmolol rapidly and reversibly increases O 2 extraction within exercising muscles of healthy humans. © 2018 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

The development and evaluation of a program for leg-strengthening exercises and balance assessment using Kinect.

PubMed

Choi, Jin-Seung; Kang, Dong-Won; Seo, Jeong-Woo; Kim, Dae-Hyeok; Yang, Seung-Tae; Tack, Gye-Rae

2016-01-01

[Purpose] In this study, a program was developed for leg-strengthening exercises and balance assessment using Microsoft Kinect. [Subjects and Methods] The program consists of three leg-strengthening exercises (knee flexion, hip flexion, and hip extension) and the one-leg standing test (OLST). The program recognizes the correct exercise posture by comparison with the range of motion of the hip and knee joints and provides a number of correct action examples to improve training. The program measures the duration of the OLST and presents this as the balance-age. The accuracy of the program was analyzed using the data of five male adults. [Results] In terms of the motion recognition accuracy, the sensitivity and specificity were 95.3% and 100%, respectively. For the balance assessment, the time measured using the existing method with a stopwatch had an absolute error of 0.37 sec. [Conclusion] The developed program can be used to enable users to conduct leg-strengthening exercises and balance assessments at home.

Pronounced Effects of Acute Endurance Exercise on Gene Expression in Resting and Exercising Human Skeletal Muscle

PubMed Central

Catoire, Milène; Mensink, Marco; Boekschoten, Mark V.; Hangelbroek, Roland; Müller, Michael; Schrauwen, Patrick; Kersten, Sander

2012-01-01

Regular physical activity positively influences whole body energy metabolism and substrate handling in exercising muscle. While it is recognized that the effects of exercise extend beyond exercising muscle, it is unclear to what extent exercise impacts non-exercising muscles. Here we investigated the effects of an acute endurance exercise bouts on gene expression in exercising and non-exercising human muscle. To that end, 12 male subjects aged 44–56 performed one hour of one-legged cycling at 50% Wmax. Muscle biopsies were taken from the exercising and non-exercising leg before and immediately after exercise and analyzed by microarray. One-legged cycling raised plasma lactate, free fatty acids, cortisol, noradrenalin, and adrenalin levels. Surprisingly, acute endurance exercise not only caused pronounced gene expression changes in exercising muscle but also in non-exercising muscle. In the exercising leg the three most highly induced genes were all part of the NR4A family. Remarkably, many genes induced in non-exercising muscle were PPAR targets or related to PPAR signalling, including PDK4, ANGPTL4 and SLC22A5. Pathway analysis confirmed this finding. In conclusion, our data indicate that acute endurance exercise elicits pronounced changes in gene expression in non-exercising muscle, which are likely mediated by changes in circulating factors such as free fatty acids. The study points to a major influence of exercise beyond the contracting muscle. PMID:23226462

Exercise training modulates functional sympatholysis and α-adrenergic vasoconstrictor responsiveness in hypertensive and normotensive individuals

PubMed Central

Mortensen, Stefan P; Nyberg, Michael; Gliemann, Lasse; Thaning, Pia; Saltin, Bengt; Hellsten, Ylva

2014-01-01

Essential hypertension is linked to an increased sympathetic vasoconstrictor activity and reduced tissue perfusion. We investigated the role of exercise training on functional sympatholysis and postjunctional α-adrenergic responsiveness in individuals with essential hypertension. Leg haemodynamics were measured before and after 8 weeks of aerobic training (3–4 times per week) in eight hypertensive (47 ± 2 years) and eight normotensive untrained individuals (46 ± 1 years) during arterial tyramine infusion, arterial ATP infusion and/or one-legged knee extensions. Before training, exercise hyperaemia and leg vascular conductance (LVC) were lower in the hypertensive individuals (P < 0.05) and tyramine lowered exercise hyperaemia and LVC in both groups (P < 0.05). Training lowered blood pressure in the hypertensive individuals (P < 0.05) and exercise hyperaemia was similar to the normotensive individuals in the trained state. After training, tyramine did not reduce exercise hyperaemia or LVC in either group. When tyramine was infused at rest, the reduction in blood flow and LVC was similar between groups, but exercise training lowered the magnitude of the reduction in blood flow and LVC (P < 0.05). There was no difference in the vasodilatory response to infused ATP or in muscle P2Y2 receptor content between the groups before and after training. However, training lowered the vasodilatory response to ATP and increased skeletal muscle P2Y2 receptor content in both groups (P < 0.05). These results demonstrate that exercise training improves functional sympatholysis and reduces postjunctional α-adrenergic responsiveness in both normo- and hypertensive individuals. The ability for functional sympatholysis and the vasodilator and sympatholytic effect of intravascular ATP appear not to be altered in essential hypertension. PMID:24860173

Similar metabolic response to lower- versus upper-body interval exercise or endurance exercise.

PubMed

Francois, Monique E; Graham, Matthew J; Parr, Evelyn B; Rehrer, Nancy J; Lucas, Samuel J E; Stavrianeas, Stasinos; Cotter, James D

2017-03-01

To compare energy use and substrate partitioning arising from repeated lower- versus upper-body sprints, or endurance exercise, across a 24-h period. Twelve untrained males (24±4 y) completed three trials in randomized order: (1) repeated sprints (five 30-s Wingate, 4.5-min recovery) on a cycle ergometer (SIT Legs ); (2) 50-min continuous cycling at 65% V̇O 2 max (END); (3) repeated sprints on an arm-crank ergometer (SIT Arms ). Respiratory gas exchange was assessed before and during exercise, and at eight points across 22h of recovery. Metabolic rate was elevated to greater extent in the first 8h after SIT Legs than SIT Arms (by 0.8±1.1kJ/min, p=0.03), and tended to be greater than END (by 0.7±1.3kJ/min, p=0.08). Total 24-h energy use (exercise+recovery) was equivalent between SIT Legs and END (p = 0.55), and SIT Legs and SIT Arms (p=0.13), but 24-h fat use was higher with SIT Legs than END (by 26±38g, p=0.04) and SIT Arms (by 27±43g, p=0.05), whereas carbohydrate use was higher with SIT Arms than SIT Legs (by 32±51g, p=0.05). Plasma volume-corrected post-exercise and fasting glucose and lipid concentrations were unchanged. Despite much lower energy use during five sprints than 50-min continuous exercise, 24-h energy use was not reliably different. However, (i) fat metabolism was greater after sprints, and (ii) carbohydrate metabolism was greater in the hours after sprints with arms than legs, while 24-h energy usage was comparable. Thus, sprints using arms or legs may be an important adjunct exercise mode for metabolic health. Copyright © 2016 Elsevier Inc. All rights reserved.

Supine exercise during lower body negative pressure effectively simulates upright exercise in normal gravity

NASA Technical Reports Server (NTRS)

Murthy, G.; Watenpaugh, D. E.; Ballard, R. E.; Hargens, A. R.

1994-01-01

Exercise within a lower body negative pressure (LBNP) chamber in supine posture was compared with similar exercise against Earth's gravity (without LBNP) in upright posture in nine healthy male volunteers. We measured footward force with a force plate, pressure in soleus and tibialis anterior muscles of the leg with transducer-tipped catheters, calf volume by strain gauge plethysmography, heart rate, and systolic and diastolic blood pressures during two conditions: 1) exercise in supine posture within an LBNP chamber during 100-mmHg LBNP (exercise-LBNP) and 2) exercise in upright posture against Earth's gravity without LBNP (exercise-1 G). Subjects exercised their ankle joints (dorsi- and plantarflexions) for 5 min during exercise-LBNP and for 5 min during exercise-1 G. Mean footward force produced during exercise-LBNP (743 +/- 37 N) was similar to that produced during exercise-1 G (701 +/- 24 N). Peak contraction pressure in the antigravity soleus muscle during exercise-LBNP (115 +/- 10 mmHg) was also similar to that during exercise-1 G (103 +/- 13 mmHg). Calf volume increased significantly by 3.3 +/- 0.5% during exercise-LBNP compared with baseline values. Calf volume did not increase significantly during exercise-1 G. Heart rate was significantly higher during exercise-LBNP (99 +/- 5 beats/min) than during exercise-1 G (81 +/- 3 beats/min). These results indicate that exercise in supine posture within an LBNP chamber can produce similar musculoskeletal stress in the legs and greater systemic cardiovascular stress than exercise in the upright posture against Earth's gravity.

Voluntary Movement Frequencies in Submaximal One- and Two-Legged Knee Extension Exercise and Pedaling

PubMed Central

Stang, Julie; Wiig, Håvard; Hermansen, Marte; Hansen, Ernst Albin

2016-01-01

Understanding of behavior and control of human voluntary rhythmic stereotyped leg movements is useful in work to improve performance, function, and rehabilitation of exercising, healthy, and injured humans. The present study aimed at adding to the existing understanding within this field. To pursue the aim, correlations between freely chosen movement frequencies in relatively simple, single-joint, one- and two-legged knee extension exercise were investigated. The same was done for more complex, multiple-joint, one- and two-legged pedaling. These particular activities were chosen because they could be considered related to some extent, as they shared a key aspect of knee extension, and because they at the same time were different. The activities were performed at submaximal intensities, by healthy individuals (n = 16, thereof eight women; 23.4 ± 2.7 years; 1.70 ± 0.11 m; 68.6 ± 11.2 kg). High and fair correlations (R-values of 0.99 and 0.75) occurred between frequencies generated with the dominant leg and the nondominant leg during knee extension exercise and pedaling, respectively. Fair to high correlations (R-values between 0.71 and 0.95) occurred between frequencies performed with each of the two legs in an activity, and the two-legged frequency performed in the same type of activity. In general, the correlations were higher for knee extension exercise than for pedaling. Correlations between knee extension and pedaling frequencies were of modest occurrence. The correlations between movement frequencies generated separately by each of the legs might be interpreted to support the following working hypothesis, which was based on existing literature. It is likely that involved central pattern generators (CPGs) of the two legs share a common frequency generator or that separate frequency generators of each leg are attuned via interneuronal connections. Further, activity type appeared to be relevant. Thus, the apparent common rhythmogenesis for the two legs appeared to be stronger for the relatively simple single-joint activity of knee extension exercise as compared to the more complex multi-joint activity of pedaling. Finally, it appeared that the shared aspect of knee extension in the related types of activities of knee extension exercise and pedaling was insufficient to cause obvious correlations between generated movement frequencies in the two types of activities. PMID:26973486

Cellular adaptation to repeated eccentric exercise-induced muscle damage.

PubMed

Stupka, N; Tarnopolsky, M A; Yardley, N J; Phillips, S M

2001-10-01

Eccentrically biased exercise results in skeletal muscle damage and stimulates adaptations in muscle, whereby indexes of damage are attenuated when the exercise is repeated. We hypothesized that changes in ultrastructural damage, inflammatory cell infiltration, and markers of proteolysis in skeletal muscle would come about as a result of repeated eccentric exercise and that gender may affect this adaptive response. Untrained male (n = 8) and female (n = 8) subjects performed two bouts (bout 1 and bout 2), separated by 5.5 wk, of 36 repetitions of unilateral, eccentric leg press and 100 repetitions of unilateral, eccentric knee extension exercises (at 120% of their concentric single repetition maximum), the subjects' contralateral nonexercised leg served as a control (rest). Biopsies were taken from the vastus lateralis from each leg 24 h postexercise. After bout 2, the postexercise force deficit and the rise in serum creatine kinase (CK) activity were attenuated. Women had lower serum CK activity compared with men at all times (P < 0.05), but there were no gender differences in the relative magnitude of the force deficit. Muscle Z-disk streaming, quantified by using light microscopy, was elevated vs. rest only after bout 1 (P < 0.05), with no gender difference. Muscle neutrophil counts were significantly greater in women 24 h after bout 2 vs. rest and bout 1 (P < 0.05) but were unchanged in men. Muscle macrophages were elevated in men and women after bout 1 and bout 2 (P < 0.05). Muscle protein content of the regulatory calpain subunit remained unchanged whereas ubiquitin-conjugated protein content was increased after both bouts (P < 0.05), with a greater increase after bout 2. We conclude that adaptations to eccentric exercise are associated with attenuated serum CK activity and, potentially, an increase in the activity of the ubiquitin proteosome proteolytic pathway.

Testing the effectiveness of a self-efficacy based exercise intervention for adults with venous leg ulcers: protocol of a randomised controlled trial

PubMed Central

2014-01-01

Background Exercise and adequate self-management capacity may be important strategies in the management of venous leg ulcers. However, it remains unclear if exercise improves the healing rates of venous leg ulcers and if a self-management exercise program based on self-efficacy theory is well adhered to. Method/design This is a randomised controlled in adults with venous leg ulcers to determine the effectiveness of a self-efficacy based exercise intervention. Participants with venous leg ulcers are recruited from 3 clinical sites in Australia. After collection of baseline data, participants are randomised to either an intervention group or control group. The control group receive usual care, as recommended by evidence based guidelines. The intervention group receive an individualised program of calf muscle exercises and walking. The twelve week exercise program integrates multiple elements, including up to six telephone delivered behavioural coaching and goal setting sessions, supported by written materials, a pedometer and two follow-up booster calls if required. Participants are encouraged to seek social support among their friends, self-monitor their weekly steps and lower limb exercises. The control group are supported by a generic information sheet that the intervention group also receive encouraging lower limb exercises, a pedometer for self-management and phone calls at the same time points as the intervention group. The primary outcome is the healing rates of venous leg ulcers which are assessed at fortnightly clinic appointments. Secondary outcomes, assessed at baseline and 12 weeks: functional ability (range of ankle motion and Tinetti gait and balance score), quality of life and self-management scores. Discussion This study seeks to address a significant gap in current wound management practice by providing evidence for the effectiveness of a home-based exercise program for adults with venous leg ulcers. Theory-driven, evidence-based strategies that can improve an individual’s exercise self-efficacy and self-management capacity could have a significant impact in improving the management of people with venous leg ulcers. Information gained from this study will provide much needed information on management of this chronic disease to promote health and independence in this population. Trial registration Australian New Zealand Clinical Trials Registry ACTRN12612000475842. PMID:25277416

Regional Skin Temperature Response to Moderate Aerobic Exercise Measured by Infrared Thermography

PubMed Central

Fernandes, Alex de Andrade; Amorim, Paulo Roberto dos Santos; Brito, Ciro José; Sillero-Quintana, Manuel; Bouzas Marins, João Carlos

2016-01-01

Background: Infrared thermography (IRT) does not require contact with the skin, and it is a convenient, reliable and non-invasive technique that can be used for monitoring the skin temperature (TSK). Objectives: The aim of this study was to monitor the variations in the regional TSK during exercise on 28 regions of interest (ROIs) (forehead, face, chest, abdomen, back, lumbar, anterior and posterior neck, and posterior and anterior views of the right and left hands, forearms, upper arms, thighs, and legs) with IRT. Patients and Methods: 12 physically active young males were monitored with IRT during the following three phases: a) 30 minutes before exercise b) while performing one hour of moderate intensity exercise on a treadmill at 60% of the VO2max, and c) 60 minutes after exercise. Results: During pre-exercise, all TSK reached a steady-state (P ≤ 0.05), which ensured adequate thermal stabilisation. At the beginning of exercise, there was a significant reduction in the TSK in most ROIs after 10 minutes of activity, except for the lower limbs (legs and thighs). After one hour of recovery, in the anterior view of the hands and thighs and in the posterior view of the legs, there were significant increases in the TSK compared to pre-exercise. Conclusions: There were significant distinctions in the skin temperature distribution during exercise according to the activity of the area under consideration during exercise, which may be important in the development of physiological models and heat flux analyses for different purposes. PMID:27217931

Enhanced Glycogen Storage of a Subcellular Hot Spot in Human Skeletal Muscle during Early Recovery from Eccentric Contractions

PubMed Central

Nielsen, Joachim; Farup, Jean; Rahbek, Stine Klejs; de Paoli, Frank Vincenzo; Vissing, Kristian

2015-01-01

Unaccustomed eccentric exercise is accompanied by muscle damage and impaired glucose uptake and glycogen synthesis during subsequent recovery. Recently, it was shown that the role and regulation of glycogen in skeletal muscle are dependent on its subcellular localization, and that glycogen synthesis, as described by the product of glycogen particle size and number, is dependent on the time course of recovery after exercise and carbohydrate availability. In the present study, we investigated the subcellular distribution of glycogen in fibers with high (type I) and low (type II) mitochondrial content during post-exercise recovery from eccentric contractions. Analysis was completed on five male subjects performing an exercise bout consisting of 15 x 10 maximal eccentric contractions. Carbohydrate-rich drinks were subsequently ingested throughout a 48 h recovery period and muscle biopsies for analysis included time points 3, 24 and 48 h post exercise from the exercising leg, whereas biopsies corresponding to prior to and at 48 h after the exercise bout were collected from the non-exercising, control leg. Quantitative imaging by transmission electron microscopy revealed an early (post 3 and 24 h) enhanced storage of intramyofibrillar glycogen (defined as glycogen particles located within the myofibrils) of type I fibers, which was associated with an increase in the number of particles. In contrast, late in recovery (post 48 h), intermyofibrillar, intramyofibrillar and subsarcolemmal glycogen in both type I and II fibers were lower in the exercise leg compared with the control leg, and this was associated with a smaller size of the glycogen particles. We conclude that in the carbohydrate-supplemented state, the effect of eccentric contractions on glycogen metabolism depends on the subcellular localization, muscle fiber’s oxidative capacity, and the time course of recovery. The early enhanced storage of intramyofibrillar glycogen after the eccentric contractions may entail important implications for muscle function and fatigue resistance. PMID:25996774

Are rate of perceived exertion and feelings of pleasure/displeasure modified in elderly women undergoing 8 week of strength training of prescribe intensity?

PubMed Central

Benites, Mariana L.; Alves, Ragami C.; Ferreira, Sandro S.; Follador, Lucio; da Silva, Sergio G.

2016-01-01

[Purpose] The aim of the present study was to verify the rate of perceived exertion and feelings of pleasure/displeasure in elderly women, who did normally perform physical exercises, following eight weeks of strength training in a constant routine. [Subjects and Methods] Eleven sedentary women were subjected to anthropometric assessment. The maximum load (100%) for each used in this study was determined by performing a test to determined the 1RM for each of them according to the protocol of Fatouros et al. and the Feeling Scale and RPE scale were explained to the women. After these initial procedures, the subjects followed a routine for strength training, performing three sets of repetitions at 70% of the one-repetition maximum for each exercise (bench press, leg extension, pulldown, leg curl) without modifying the exercises and their execution order. The frequency of training was three days per week. ANOVA was used to analyze the behavior of the dependent variable, and the post hoc tests were used to identify significant differences. [Results] Strength increased only in the fifth week. The rate of perceived exertion showed a reduction only in the fifth week in the leg extension, pulldown, leg curl. [Conclusion] The percentage of 70% the one-repetition maximum recommended to increase the strength gains and hypertrophy of skeletal muscle does not provide feelings of displeasure when performing proposed exercise. However, it may be possible to modulate this percentage to obtain more pleasant feelings over two months. PMID:27065524

Are rate of perceived exertion and feelings of pleasure/displeasure modified in elderly women undergoing 8 week of strength training of prescribe intensity?

PubMed

Benites, Mariana L; Alves, Ragami C; Ferreira, Sandro S; Follador, Lucio; da Silva, Sergio G

2016-01-01

[Purpose] The aim of the present study was to verify the rate of perceived exertion and feelings of pleasure/displeasure in elderly women, who did normally perform physical exercises, following eight weeks of strength training in a constant routine. [Subjects and Methods] Eleven sedentary women were subjected to anthropometric assessment. The maximum load (100%) for each used in this study was determined by performing a test to determined the 1RM for each of them according to the protocol of Fatouros et al. and the Feeling Scale and RPE scale were explained to the women. After these initial procedures, the subjects followed a routine for strength training, performing three sets of repetitions at 70% of the one-repetition maximum for each exercise (bench press, leg extension, pulldown, leg curl) without modifying the exercises and their execution order. The frequency of training was three days per week. ANOVA was used to analyze the behavior of the dependent variable, and the post hoc tests were used to identify significant differences. [Results] Strength increased only in the fifth week. The rate of perceived exertion showed a reduction only in the fifth week in the leg extension, pulldown, leg curl. [Conclusion] The percentage of 70% the one-repetition maximum recommended to increase the strength gains and hypertrophy of skeletal muscle does not provide feelings of displeasure when performing proposed exercise. However, it may be possible to modulate this percentage to obtain more pleasant feelings over two months.

Periodization effects during short-term resistance training with equated exercise variables in females.

PubMed

Pelzer, Thiemo; Ullrich, Boris; Pfeiffer, Mark

2017-03-01

During resistance training, volume and load can be altered either gradually (traditional periodization: TP) or with frequent changes between subsequent sessions (daily undulating periodization: DUP). We hypothesized that the periodization model employed would not impact upon training-induced adaptations when exercise variables are equated. Nineteen females (22.0 years, moderate resistance training experience of 27.9 months) performed 6 weeks of knee extensor training with 3 weekly sessions exercising one leg using TP and the contralateral leg using DUP. Training load varied between 40, 60, and 80% of one repetition maximum (1RM). Volume, range of motion, and time under tension were equated for each leg with a biofeedback software. Dynamometry, surface EMG and ultrasonography were used to determine temporal changes of knee extensor maximum voluntary strength (MVC), neural drive of the M. quadriceps femoris (QF) and vastus lateralis (VL) and rectus femoris (RF) muscle architecture. Significant (P < 0.05) gains for isometric (TP 15%, DUP 13%) and isokinetic-concentric (TP 8%, DUP 10%) MVC and knee extensor 1RM (TP 18%, DUP 24%) occurred post training. VL and RF-muscle thickness showed significant (P < 0.05) increases ranging from 12 to 20% for TP and from 13 to 19% for DUP. Furthermore, significant (P < 0.05) increases in VL-pennation angle and VL-fascicle length occurred in both legs while QF EMG remained unchanged. No significant temporal differences were found between both models, displaying similar small to large effect sizes. Periodization is no adaptation trigger during short-term resistance training with equated exercise variables.

Exercise order affects the total training volume and the ratings of perceived exertion in response to a super-set resistance training session

PubMed Central

Balsamo, Sandor; Tibana, Ramires Alsamir; Nascimento, Dahan da Cunha; de Farias, Gleyverton Landim; Petruccelli, Zeno; de Santana, Frederico dos Santos; Martins, Otávio Vanni; de Aguiar, Fernando; Pereira, Guilherme Borges; de Souza, Jéssica Cardoso; Prestes, Jonato

2012-01-01

The super-set is a widely used resistance training method consisting of exercises for agonist and antagonist muscles with limited or no rest interval between them – for example, bench press followed by bent-over rows. In this sense, the aim of the present study was to compare the effects of different super-set exercise sequences on the total training volume. A secondary aim was to evaluate the ratings of perceived exertion and fatigue index in response to different exercise order. On separate testing days, twelve resistance-trained men, aged 23.0 ± 4.3 years, height 174.8 ± 6.75 cm, body mass 77.8 ± 13.27 kg, body fat 12.0% ± 4.7%, were submitted to a super-set method by using two different exercise orders: quadriceps (leg extension) + hamstrings (leg curl) (QH) or hamstrings (leg curl) + quadriceps (leg extension) (HQ). Sessions consisted of three sets with a ten-repetition maximum load with 90 seconds rest between sets. Results revealed that the total training volume was higher for the HQ exercise order (P = 0.02) with lower perceived exertion than the inverse order (P = 0.04). These results suggest that HQ exercise order involving lower limbs may benefit practitioners interested in reaching a higher total training volume with lower ratings of perceived exertion compared with the leg extension plus leg curl order. PMID:22371654

Effect of stretching program in an industrial workplace on hamstring flexibility and sagittal spinal posture of adult women workers: a randomized controlled trial.

PubMed

Muyor, José M; López-Miñarro, Pedro A; Casimiro, Antonio J

2012-01-01

To determine the effect of a stretching program performed in the workplace on the hamstring muscle extensibility and sagittal spinal posture of adult women. Fifty-eight adult women volunteers (mean age of 44.23 ± 8.87 years) from a private fruit and vegetable company were randomly assigned to experimental (n=27) or control (n=31) groups. The experimental group performed three exercises of hamstrings stretching of 20 seconds per exercise, three sessions a week for a period of 12 weeks. The control group did not participate in any hamstring stretching program. Hamstring flexibility was evaluated through the passive straight leg raise test and toe-touch test, performed both before and after the stretching program. Thoracic and lumbar curvatures and pelvic inclination were measured in relaxed standing and toe-touch test with a Spinal Mouse. Significant increases (p < 0.01) in toe-touch score and straight leg raise angle (in both legs) were found in the experimental group during post-test, while the control group showed a non-significant decrease for both toe-touch score and straight leg raise test. A significant decrease in thoracic curve and significant increase in pelvic inclination were found in the toe-touch test for the experimental group (p <0.05). However, no significant changes were found in standing posture for any group. Hamstring stretching exercises performed in the working place are effective for increasing hamstring muscle extensibility. This increase generates a more aligned thoracic curve and more anterior pelvic inclination when maximal trunk flexion is performed.

Effects of ipsilateral anterior thigh soft tissue stretching on passive unilateral straight-leg raise.

PubMed

Clark, S; Christiansen, A; Hellman, D F; Hugunin, J W; Hurst, K M

1999-01-01

Randomized 3-group pretest-posttest with blind assessment of outcome. The purpose of this study was to examine the effect of sagittal plane hold-relax exercise applied to the ipsilateral anterior thigh, and prone positioning on passive unilateral straight-leg raise measurements. Straight-leg raising has been viewed as a measurement for hamstring muscle length, but literature suggests that other structures may affect this measurement. Sixty subjects (45 men, 15 women) qualified for inclusion into the study based on a straight-leg raise measurement of < or = 65 degrees. Subjects were randomly assigned to one of three groups: control, static stretch, or sagittal plane hold-relax exercise. Pretest and posttest straight-leg raise measurements of the right lower extremity were performed for each subject. A 1-way ANOVA of the change scores showed a significant difference between groups. A Tukey post hoc analysis of the change scores showed that both treatment groups' means differed significantly from the control group and from each other, with the sagittal plane hold-relax group exhibiting the largest change (mean of 7.8 degrees +/- 2.8 degrees). The results of this study show that sagittal plane hold-relax exercise and passive prone results of this study show that sagittal plane hold-relax and passive prone positioning can significantly increase straight-leg raise range of motion, however the sagittal plane hold-relax stretching of the anterior thigh is more effective than passive prone positioning.

Development and validation of a questionnaire to measure the severity of functional limitations and reduction of sports ability in German-speaking patients with exercise-induced leg pain.

PubMed

Nauck, Tanja; Lohrer, Heinz; Padhiar, Nat; King, John B

2015-01-01

Currently, there is no generally agreed measure available to quantify a subject's perceived severity of exercise-induced leg pain symptoms. The aim of this study was to develop and validate a questionnaire that measures the severity of symptoms that impact on function and sports ability in patients with exercise-induced leg pain. The exercise-induced leg pain questionnaire for German-speaking patients (EILP-G) was developed in five steps: (1) initial item generation, (2) item reduction, (3) pretesting, (4) expert meeting and (5) validation. The resulting EILP-G was tested for reliability, validity and internal consistency in 20 patients with exercise-induced leg pain, 20 asymptomatic track and field athletes serving as a population at risk and 33 asymptomatic sport students. The patient group scored the EILP-G questionnaire significantly lower than both control groups (each p<0.001). Test-retest demonstrates an excellent reliability in all tested groups (Intraclass Correlation Coefficient, ICC=0.861-0.987). Concurrent validity of the EILP-G questionnaire showed a substantial agreement when correlated with the chronic exertional compartment syndrome classification system of Schepsis (r=-0.743; p<0.001). Internal consistency for the EILP-G questionnaire was 0.924. EILP-G questionnaire is a valid and reliable self-administered and disease-related outcome tool to measure the severity of symptoms that impact on function and sports ability in patients with exercise-induced leg pain. It can be recommended as a robust tool for measuring the subjectively perceived severity in German-speaking patients with exercise-induced leg pain. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

The influence of estradiol on muscle damage and leg strength after intense eccentric exercise.

PubMed

Minahan, Clare; Joyce, Sarah; Bulmer, Andrew C; Cronin, Neil; Sabapathy, Surendran

2015-07-01

To examine the influence of estradiol on muscle damage and leg strength after intense eccentric exercise. Eight men (MEN), eight normally menstruating women (WomenNM), and eight women using oral contraceptives (WomenOC) participated in this study. Subjects performed 240 maximal-effort bilateral eccentric contractions of the quadriceps muscle groups designed to elicit exercise-induced muscle damage (EiMD). Serum creatine kinase (CK), myoglobin (Mb), and fatty acid-binding protein (FABP) concentrations were measured before (pre-) EiMD, as well as 0, 6, 24, and 48 h post-EiMD. Peak isometric quadriceps torque (i.e., leg strength) was measured pre-EiMD, as well as 24 and 48 h post-EiMD. The increases in CK, Mb, and FABP concentrations from pre- to post-EiMD were greater in MEN (10-fold, 15-fold, and fourfold, respectively) and WomenOC (sevenfold, 11-fold, and ninefold) compared with WomenNM (five-, six-, and threefold; p < 0.05). The decline in leg strength was about 10 % pre- to 24 h post-EiMD in all groups and decreased a further 10-15 % by 48 h post-EiMD in the MEN and WomenOC only. Our findings suggest an important role of estradiol in blunting the muscle damage response to intense eccentric exercise and preserving muscle function after EiMD.

Effect of whole-body vibration on neuromuscular performance and body composition for females 65 years and older: a randomized-controlled trial.

PubMed

von Stengel, S; Kemmler, W; Engelke, K; Kalender, W A

2012-02-01

We examined whether the effect of multipurpose exercise can be enhanced by whole-body vibration (WBV). One hundred and fifty-one post-menopausal women (68.5 ± 3.1 years) were randomly assigned to three groups: (1) a training group (TG); (2) training including vibration (VTG); and (3) a wellness control group (CG). TG and VTG performed the same training program twice weekly (60 min), consisting of aerobic and strength exercises, with the only difference that leg strength exercises (15 min) were performed with (VTG) or without (TG) vibration. CG performed a low-intensity "wellness" program. At baseline and after 18 months, body composition was determined using dual-X-ray-absorptiometry. Maximum isometric strength was determined for the legs and the trunk region. Leg power was measured by countermovement jumps using a force-measuring plate. In the TG lean body mass, total body fat, and abdominal fat were favorably affected, but no additive effects were generated by the vibration stimulus. However, concerning muscle strength and power, there was a tendency in favor of the VTG. Only vibration training resulted in a significant increase of leg and trunk flexion strength compared with CG. In summary, WBV embedded in a multipurpose exercise program showed minor additive effects on body composition and neuromuscular performance. © 2010 John Wiley & Sons A/S.

Cortical activation pattern during shoulder simple versus vibration exercises: a functional near infrared spectroscopy study.

PubMed

Jang, Sung Ho; Yeo, Sang Seok; Lee, Seung Hyun; Jin, Sang Hyun; Lee, Mi Young

2017-08-01

To date, the cortical effect of exercise has not been fully elucidated. Using the functional near infrared spectroscopy, we attempted to compare the cortical effect between shoulder vibration exercise and shoulder simple exercise. Eight healthy subjects were recruited for this study. Two different exercise tasks (shoulder vibration exercise using the flexible pole and shoulder simple exercise) were performed using a block paradigm. We measured the values of oxygenated hemoglobin in the four regions of interest: the primary sensory-motor cortex (SM1 total, arm somatotopy, and leg and trunk somatotopy), the premotor cortex, the supplementary motor area, and the prefrontal cortex. During shoulder vibration exercise and shoulder simple exercise, cortical activation was observed in SM1 (total, arm somatotopy, and leg and trunk somatotopy), premotor cortex, supplementary motor area, and prefrontal cortex. Higher oxygenated hemoglobin values were also observed in the areas of arm somatotopy of SM1 compared with those of other regions of interest. However, no significant difference in the arm somatotopy of SM1 was observed between the two exercises. By contrast, in the leg and trunk somatotopy of SM1, shoulder vibration exercise led to a significantly higher oxy-hemoglobin value than shoulder simple exercise. These two exercises may result in cortical activation effects for the motor areas relevant to the shoulder exercise, especially in the arm somatotopy of SM1. However, shoulder vibration exercise has an additional cortical activation effect for the leg and trunk somatotopy of SM1.

Cardiorespiratory deconditioning with static and dynamic leg exercise during bed rest.

PubMed

Stremel, R W; Convertino, V A; Bernauer, E M; Greenleaf, J E

1976-12-01

Bed rest deconditioning was assessed in seven healthy men (19-22 yr) following three 14-day periods of controlled activity during recumbency by measuring submaximal and maximal oxygen uptake (VO2), ventilation (VE), heart rate, and plasma volume. Exercise regimens were performed in the supine position and included a) two 30-min periods daily of intermittent static exercise at 21% of maximal leg extension force, and b) two 30-min periods of dynamic bicycle ergometer exercise daily at 68% of VO2max. No prescribed exercise was performed during the third bed rest period. Compared with their respective pre-bed rest control values, VO2max decreased (P less than 0.05) under all exercise conditions; -12.3% with no exercise, -9.2% with dynamic exercise, but only -4.8% with static exercise. Maximal heart rate was increased by 3.3% to 4.9% (P less than 0.05) under the three exercise conditions, while plasma volume decreased (P less than 0.05) -15.1% with no exercise and -10.1% with static, but only -7.8% (NS) with dynamic exercise. Since neither the static nor dynamic exercise training regimes minimized the changes in all the variables studied, some combination of these two types of exercise may be necessary for maximum protection from the effects of the bed deconditioning.

Impaired Skeletal Muscle Vasodilation during Exercise in Heart Failure with Preserved Ejection Fraction

PubMed Central

Lee, Joshua F.; Barrett-O’Keefe, Zachary; Nelson, Ashley D.; Garten, Ryan S.; Ryan, John J.; Nativi-Nicolau, Jose N.; Richardson, Russell S.; Wray, D. Walter

2016-01-01

Background Exercise intolerance is a hallmark symptom of heart failure patients with preserved ejection fraction (HFpEF), which may be related to an impaired ability to appropriately increase blood flow to the exercising muscle. Methods We evaluated leg blood flow (LBF, ultrasound Doppler), heart rate (HR), stroke volume (SV), cardiac output (CO), and mean arterial blood pressure (MAP, photoplethysmography) during dynamic, single leg knee-extensor (KE) exercise in HFpEF patients (n = 21; 68 ± 2 yrs) and healthy controls (n = 20; 71 ± 2 yrs). Results HFpEF patients exhibited a marked attrition during KE exercise, with only 60% able to complete the exercise protocol. In participants who completed all exercise intensities (0-5-10-15W; HFpEF, n = 13; Controls, n = 16), LBF was not different at 0W and 5W, but was 15-25% lower in HFpEF compared to controls at 10W and 15W (P < 0.001). Likewise, leg vascular conductance (LVC), an index of vasodilation, was not different at 0W and 5W, but was 15-20% lower in HFpEF compared to controls at 10W and 15W (P < 0.05). In contrast to these peripheral deficits, exercise-induced changes in central variables (HR, SV, CO), as well as MAP, were similar between groups. Conclusions These data reveal a marked reduction in LBF and LVC in HFpEF patients during exercise that cannot be attributed to a disease-related alteration in central hemodynamics, suggesting that impaired vasodilation in the exercising skeletal muscle vasculature may play a key role in the exercise intolerance associated with this patient population. PMID:26970959

A prospective study of gait related risk factors for exercise-related lower leg pain.

PubMed

Willems, T M; De Clercq, D; Delbaere, K; Vanderstraeten, G; De Cock, A; Witvrouw, E

2006-01-01

The purpose of this study was to determine prospectively gait related risk factors for exercise-related lower leg pain (ERLLP) in 400 physical education students. Static lower leg alignment was determined, and 3D gait kinematics combined with plantar pressure profiles were collected. After this evaluation, all sports injuries were registered by the same sports physician during the duration of the study. Forty six subjects developed ERLLP and 29 of them developed bilateral symptoms thus giving 75 symptomatic lower legs. Bilateral lower legs of 167 subjects who developed no injuries in the lower extremities served as controls. Cox regression analysis revealed that subjects who developed ERLLP had an altered running pattern before the injury compared to the controls and included (1) a significantly more central heel-strike, (2) a significantly increased pronation, accompanied with more pressure underneath the medial side of the foot, and (3) a significantly more lateral roll-off. These findings suggest that altered biomechanics play a role in the genesis of ERLLP and thus should be considered in prevention and rehabilitation.

Muscle hypertrophy and fast fiber type conversions in heavy resistance-trained women.

PubMed

Staron, R S; Malicky, E S; Leonardi, M J; Falkel, J E; Hagerman, F C; Dudley, G A

1990-01-01

Twenty-four women completed a 20-week heavy-resistance weight training program for the lower extremity. Workouts were twice a week and consisted of warm-up exercises followed by three sets each of full squats, vertical leg presses, leg extensions, and leg curls. All exercises were performed to failure using 6-8 RM (repetition maximum). Weight training caused a significant increase in maximal isotonic strength (1 RM) for each exercise. After training, there was a decrease in body fat percentage (p less than 0.05), and an increase in lean body mass (p less than 0.05) with no overall change in thigh girth. Biopsies were obtained before and after training from the superficial portion of the vastus lateralis muscle. Sections were prepared for histological and histochemical examination. Six fiber types (I, IC, IIC, IIA, IIAB, and IIB) were distinguished following routine myofibrillar adenosine triphosphatase histochemistry. Areas were determined for fiber types I, IIA, and IIAB + IIB. The heavy-resistance training resulted in significant hypertrophy of all three groups: I (15%), IIA (45%), and IIAB + IIB (57%). These data are similar to those in men and suggest considerable hypertrophy of all major fiber types is also possible in women if exercise intensity and duration are sufficient. In addition, the training resulted in a significant decrease in the percentage of IIB with a concomitant increase in IIA fibers, suggesting that strength training may lead to fiber conversions.

An index for breathlessness and leg fatigue.

PubMed

Borg, E; Borg, G; Larsson, K; Letzter, M; Sundblad, B-M

2010-08-01

The features of perceived symptoms causing discontinuation of strenuous exercise have been scarcely studied. The aim was to characterize the two main symptoms causing the discontinuation of heavy work in healthy persons as well as describe the growth of symptoms during exercise. Breathlessness (b) and leg fatigue (l) were assessed using the Borg CR10 Scale and the Borg CR100 (centiMax) Scale, during a standardized exercise test in 38 healthy subjects (24-71 years). The b/l-relationships were calculated for terminal perceptions (ERI(b/l)), and the growth of symptoms determined by power functions for the whole test, as well as by growth response indexes (GRI). This latter index was constructed as a ratio between power levels corresponding to a very strong and a moderate perception. In the majority (71%) of the test subjects, leg fatigue was the dominant symptom at the conclusion of exercise (P<0.001) and the b/l ratio was 0.77 (CR10) and 0.75 (CR100), respectively. The GRI for breathlessness and leg fatigue was similar, with good correlations between GRI and the power function exponent (P<0.005). In healthy subjects, leg fatigue is the most common cause for discontinuing an incremental exercise test. The growth functions for breathlessness and leg fatigue during work are, however, almost parallel.

Chronic endurance exercise training offsets the age-related attenuation in contraction-induced rapid vasodilation

PubMed Central

Hughes, William E.; Ueda, Kenichi

2016-01-01

Aging is associated with attenuated contraction-induced rapid onset vasodilation (ROV). We sought to examine whether chronic exercise training would improve ROV in older adults. Additionally, we examined whether a relationship between cardiorespiratory fitness and ROV exists in young and older adults. Chronically exercise-trained older adults (n = 16; 66 ± 2 yr, mean ± SE) performed single muscle contractions in the forearm and leg at various intensities. Brachial and femoral artery diameter and blood velocity were measured using Doppler ultrasound. Vascular conductance (VC) was calculated as the quotient of blood flow (ml/min) and mean arterial pressure (mmHg). These data were compared with our previously published work from an identical protocol in 16 older untrained (66 ± 1 yr, mean ± SE) and 14 young (23 ± 1 yr) adults. Peak (ΔVCpeak) and total vasodilator (VCtotal) responses were greater in trained compared with untrained older adults across leg exercise intensities (P < 0.05). There were no differences in responses between trained older and young adults in the arm or leg at any exercise intensity (P > 0.05). Comparison of ΔVCpeak in a subset of subjects at an absolute workload in the leg revealed that trained older adults exhibited augmented responses relative to untrained older adults. Exercise capacity (V̇o2 peak) was associated with ΔVCpeak and VCtotal across arm (r = 0.59–0.64) and leg exercise intensities (r = 0.55–0.68, P < 0.05) in older adults. Our data demonstrate that 1) chronic exercise training improves ROV in the arm and leg of trained older adults, such that age-related differences in ROV are abolished, and 2) VO2peak is associated with ΔVCpeak responses in both limbs of older adults. PMID:27032899

Chronic endurance exercise training offsets the age-related attenuation in contraction-induced rapid vasodilation.

PubMed

Hughes, William E; Ueda, Kenichi; Casey, Darren P

2016-06-01

Aging is associated with attenuated contraction-induced rapid onset vasodilation (ROV). We sought to examine whether chronic exercise training would improve ROV in older adults. Additionally, we examined whether a relationship between cardiorespiratory fitness and ROV exists in young and older adults. Chronically exercise-trained older adults (n = 16; 66 ± 2 yr, mean ± SE) performed single muscle contractions in the forearm and leg at various intensities. Brachial and femoral artery diameter and blood velocity were measured using Doppler ultrasound. Vascular conductance (VC) was calculated as the quotient of blood flow (ml/min) and mean arterial pressure (mmHg). These data were compared with our previously published work from an identical protocol in 16 older untrained (66 ± 1 yr, mean ± SE) and 14 young (23 ± 1 yr) adults. Peak (ΔVCpeak) and total vasodilator (VCtotal) responses were greater in trained compared with untrained older adults across leg exercise intensities (P < 0.05). There were no differences in responses between trained older and young adults in the arm or leg at any exercise intensity (P > 0.05). Comparison of ΔVCpeak in a subset of subjects at an absolute workload in the leg revealed that trained older adults exhibited augmented responses relative to untrained older adults. Exercise capacity (V̇o2 peak) was associated with ΔVCpeak and VCtotal across arm (r = 0.59-0.64) and leg exercise intensities (r = 0.55-0.68, P < 0.05) in older adults. Our data demonstrate that 1) chronic exercise training improves ROV in the arm and leg of trained older adults, such that age-related differences in ROV are abolished, and 2) VO2peak is associated with ΔVCpeak responses in both limbs of older adults. Copyright © 2016 the American Physiological Society.

Resistance exercise increases intramuscular NF-κb signaling in untrained males.

PubMed

Townsend, Jeremy R; Stout, Jeffrey R; Jajtner, Adam R; Church, David D; Beyer, Kyle S; Oliveira, Leonardo P; La Monica, Michael B; Riffe, Joshua J; Muddle, Tyler W D; Baker, Kayla M; Fukuda, David H; Roberts, Michael D; Hoffman, Jay R

2016-12-01

The NF-κB signaling pathway regulates multiple cellular processes following exercise stress. This study aims to examine the effects of an acute lower-body resistance exercise protocol and subsequent recovery on intramuscular NF-κB signaling. Twenty-eight untrained males were assigned to either a control (CON; n = 11) or exercise group (EX; n = 17) and completed a lower-body resistance exercise protocol consisting of the back squat, leg press, and leg extension exercises. Skeletal muscle microbiopsies were obtained from the vastus lateralis pre-exercise (PRE), 1-hour (1H), 5-hours (5H), and 48-hours (48H) post-resistance exercise. Multiplex signaling assay kits (EMD Millipore, Billerica, MA, USA) were used to quantify the total protein (TNFR1, c-Myc) or phosphorylation status of proteins belonging to the NF-κB signaling pathway (IKKa/b, IkBα, NF-κB) using multiplex protein assay. Repeated measures ANOVA analysis was used to determine the effects of the exercise bout on intramuscular signaling at each time point. Additionally, change scores were analyzed by magnitude based inferences to determine a mechanistic interpretation. Repeated measures ANOVA indicated a trend for a two-way interaction between the EX and CON Group (p = 0.064) for c-Myc post resistance exercise. Magnitude based inference analysis suggest a "Very Likely" increase in total c-Myc from PRE-5H and a "Likely" increase in IkBα phosphorylation from PRE-5H post-resistance exercise. Results indicated that c-Myc transcription factor is elevated following acute intense resistance exercise in untrained males. Future studies should examine the role that post-resistance exercise NF-κβ signaling plays in c-Myc induction, ribosome biogenesis and skeletal muscle regeneration.

Leg Stiffness in Female Soccer Players: Intersession Reliability and the Fatiguing Effects of Soccer-Specific Exercise.

PubMed

De Ste Croix, Mark B A; Hughes, Jonathan D; Lloyd, Rhodri S; Oliver, Jon L; Read, Paul J

2017-11-01

De Ste Croix, MBA, Hughes, JD, Lloyd, RS, Oliver, JL, and Read, PJ. Leg stiffness in female soccer players: intersession reliability and the fatiguing effects of soccer-specific exercise. J Strength Cond Res 31(11): 3052-3058, 2016-Low levels of leg stiffness and reduced leg stiffness when fatigue is present compromise physical performance and increase injury risk. The purpose of this study was to (a) determine the reliability of leg stiffness measures obtained from contact mat data and (b) explore age-related differences in leg stiffness after exposure to a soccer-specific fatigue protocol in young female soccer players. Thirty-seven uninjured female youth soccer players divided into 3 subgroups based on chronological age (under 13 [U13], under 15 [U15], and under 17 [U17] year-olds) volunteered to participate in the study. After baseline data collection, during which relative leg stiffness, contact time, and flight time were collected, participants completed an age-appropriate soccer-specific fatigue protocol (SAFT). Upon completion of the fatigue protocol, subjects were immediately retested. Intersession reliability was acceptable and could be considered capable of detecting worthwhile changes in performance. Results showed that leg stiffness decreased in the U13 year-olds, was maintained in the U15 age group, and increased in the U17 players. Contact times and flight times did not change in the U13 and U15 year-olds, but significantly decreased and increased, respectively, in the U17 age group. The data suggest that age-related changes in the neuromuscular control of leg stiffness are present in youth female soccer players. Practitioners should be aware of these discrepancies in neuromuscular responses to soccer-specific fatigue, and should tailor training programs to meet the needs of individuals, which may subsequently enhance performance and reduce injury risk.

Effect of fluid ingestion on orthostatic responses following acute exercise

NASA Technical Reports Server (NTRS)

Davis, J. E.; Fortney, S. M.

1997-01-01

Orthostatic tolerance is impaired following an acute bout of exercise. This study examined the effect of fluid ingestion following treadmill exercise in restoring the cardiovascular responses to an orthostatic stress. Five men (age, 29.6 +/- 3.4 yrs) were exposed to a graded lower body negative (LBNP) pressure protocol (0 to -50 mmHg) during euhydration without exercise (C), 20 minutes after exercise dehydration (D), 20 minutes after exercise and fluid ingestion (FI20), and 60 minutes after exercise and fluid ingestion (FI60). Fluid ingestion (mean +/- SE) consisted of water-ingestion equivalent to 50% of the body weight lost during exercise (520 +/- 15 ml). Exercise dehydration resulted in significantly higher heart rates (119 +/- 8 vs 82 +/- 7 bpm), lower systolic blood pressures (95 +/- 1.7 vs 108 +/- 2.3 mmHg), a smaller increase in leg circumference (3.7 +/- 4 vs 6.9 +/- 1.0 mm), and an attenuated increase in total peripheral resistance (2.58 +/- 1.2 vs 4.28 +/- 0.9 mmHg/L/min) at -50 mmHg LBNP compared to the C condition. Fluid ingestion (both 20 and 60), partially restored the heart rate, systolic blood pressure, and total peripheral resistance responses to LBNP, but did not influence the change in leg circumference during LBNP (4 +/- 0.3 for R20 and 2.8 +/- 0.4 mm for R60). These data illustrate the effectiveness of fluid ingestion on improving orthostatic responses following exercise, and suggest that dehydration is a contributing factor to orthostatic intolerance following exercise.

A 4-week, lifestyle-integrated, home-based exercise training programme elicits improvements in physical function and lean mass in older men and women: a pilot study.

PubMed

Cegielski, Jessica; Brook, Matthew S; Quinlan, Jonathan I; Wilkinson, Daniel J; Smith, Kenneth; Atherton, Philip J; Phillips, Bethan E

2017-01-01

Developing alternative exercise programmes that can alleviate certain barriers to exercise such as psychological, environmental or socio-economical barriers, but provide similar physiological benefits e.g. increases in muscle mass and strength, is of grave importance. This pilot study aimed to assess the efficacy of an unsupervised, 4-week, whole-body home-based exercise training (HBET) programme, incorporated into daily living activities, on skeletal muscle mass, power and strength. Twelve healthy older volunteers (63±3 years, 7 men: 5 women, BMI: 29±1 kg/m²) carried out the 4-week "lifestyle-integrated" HBET of 8 exercises, 3x12 repetitions each, every day. Before and after HBET, a number of physical function tests were carried out: unilateral leg extension 1-RM (one- repetition maximum), MVC (maximal voluntary contraction) leg extension, lower leg muscle power (via Nottingham Power Rig), handgrip strength and SPPBT (short physical performance battery test). A D 3 -Creatine method was used for assessment of whole-body skeletal muscle mass, and ultrasound was used to measure the quadriceps cross-sectional area (CSA) and vastus lateralis muscle thickness. Four weeks HBET elicited significant (p<0.05) improvements in leg muscle power (276.7±38.5 vs. 323.4±43.4 W), maximal voluntary contraction (60°: 154.2±18.4 vs. 168.8±15.2 Nm, 90°: 152.1±10.5 vs. 159.1±11.4 Nm) and quadriceps CSA (57.5±5.4 vs. 59.0±5.3 cm 2 ), with a trend for an increase in leg strength (1-RM: 45.7±5.9 vs. 49.6±6.0 kg, P=0.08). This was despite there being no significant differences in whole-body skeletal muscle mass, as assessed via D 3 -Creatine. This study demonstrates that increases in multiple aspects of muscle function can be achieved in older adults with just 4-weeks of "lifestyle-integrated" HBET, with a cost-effective means. This training mode may prove to be a beneficial alternative for maintaining and/or improving muscle mass and function in older adults.

Effect of 8 weeks of free-weight and machine-based strength training on strength and power performance

PubMed Central

Wirth, Klaus; Hartmann, Hagen; Sander, Andre; Mickel, Christoph

2016-01-01

Abstract The aim of this study was to evaluate the effectiveness of free-weight and machine-based exercises to increase different strength and speed-strength variables. One hundred twenty male participants (age: 23.8 ± 2.5 years; body height: 181.0 ± 6.8 cm; body mass: 80.2 ± 8.9 kg) joined the study. The 2 experimental groups completed an 8 week periodized strength training program that included 2 training sessions per week. The exercises that were used in the strength training programs were the parallel barbell squat and the leg press. Before and after the training period, the 1-repetition-maximum in the barbell squat and the leg press, the squat jump, the countermovement jump and unilateral isometric force (maximal isometric force and the rate of force development) were evaluated. To compare each group pre vs. post-intervention, analysis of variance with repeated measures and Scheffé post-hoc tests were used. The leg press group increased their 1-repetition-maximum significantly (p < 0.001), while in the squat group such variables as 1-repetition-maximum, the squat jump and the countermovement jump increased significantly (p < 0.001). The maximal isometric force showed no statistically significant result for the repeated measures factor, while the rate of force development of the squat group even showed a statistically significant decrease. Differences between the 2 experimental groups were detected for the squat jump and the countermovement jump. In comparison with the leg press, the squat might be a better strength training exercise for the development of jump performance. PMID:28149424

Effect of 8 weeks of free-weight and machine-based strength training on strength and power performance.

PubMed

Wirth, Klaus; Keiner, Michael; Hartmann, Hagen; Sander, Andre; Mickel, Christoph

2016-12-01

The aim of this study was to evaluate the effectiveness of free-weight and machine-based exercises to increase different strength and speed-strength variables. One hundred twenty male participants (age: 23.8 ± 2.5 years; body height: 181.0 ± 6.8 cm; body mass: 80.2 ± 8.9 kg) joined the study. The 2 experimental groups completed an 8 week periodized strength training program that included 2 training sessions per week. The exercises that were used in the strength training programs were the parallel barbell squat and the leg press. Before and after the training period, the 1-repetition-maximum in the barbell squat and the leg press, the squat jump, the countermovement jump and unilateral isometric force (maximal isometric force and the rate of force development) were evaluated. To compare each group pre vs. post-intervention, analysis of variance with repeated measures and Scheffé post-hoc tests were used. The leg press group increased their 1-repetition-maximum significantly (p < 0.001), while in the squat group such variables as 1-repetition-maximum, the squat jump and the countermovement jump increased significantly (p < 0.001). The maximal isometric force showed no statistically significant result for the repeated measures factor, while the rate of force development of the squat group even showed a statistically significant decrease. Differences between the 2 experimental groups were detected for the squat jump and the countermovement jump. In comparison with the leg press, the squat might be a better strength training exercise for the development of jump performance.

Feasibility of ballistic strengthening exercises in neurologic rehabilitation.

PubMed

Williams, Gavin; Clark, Ross A; Hansson, Jessica; Paterson, Kade

2014-09-01

Conventional methods for strength training in neurologic rehabilitation are not task specific for walking. Ballistic strength training was developed to improve the functional transfer of strength training; however, no research has investigated this in neurologic populations. The aim of this pilot study was to evaluate the feasibility of applying ballistic principles to conventional leg strengthening exercises in individuals with mobility limitations as a result of neurologic injuries. Eleven individuals with neurologic injuries completed seated and reclined leg press using conventional and ballistic techniques. A 2 × 2 repeated-measures analysis of variance was used to compare power measures (peak movement height and peak velocity) between exercises and conditions. Peak jump velocity and peak jump height were greater when using the ballistic jump technique rather than the conventional concentric technique (P < 0.01). These findings suggest that when compared with conventional strengthening exercises, the incorporation of ballistic principles was associated with increased peak height and peak velocities.

Chronic Exertional Compartment Syndrome.

PubMed

Braver, Richard T

2016-04-01

Increased tissue pressure within a fascial compartment may be the result from any increase in volume within its contents, or any decrease in size of the fascial covering or its distensibility. This may lead to symptoms of leg tightness, pain or numbness brought about by exercise. There are multiple differential diagnoses of exercise induced leg pain and the proper diagnoses of chronic exertional compartment syndrome (CECS) is made by a careful history and by exclusion of other maladies and confirmed by compartment syndrome testing as detailed in this text. Surgical fasciotomies for the anterior, lateral, superficial and deep posterior compartments are described in detail along with ancillary procedures for chronic shin splints that should allow the athlete to return to competitive activity. Copyright © 2016 Elsevier Inc. All rights reserved.

Potentiation of cGMP signaling increases oxygen delivery and oxidative metabolism in contracting skeletal muscle of older but not young humans

PubMed Central

Nyberg, Michael; Piil, Peter; Egelund, Jon; Sprague, Randy S; Mortensen, Stefan P; Hellsten, Ylva

2015-01-01

Aging is associated with progressive loss of cardiovascular and skeletal muscle function. The impairment in physical capacity with advancing age could be related to an insufficient peripheral O2 delivery to the exercising muscles. Furthermore, the mechanisms underlying an impaired blood flow regulation remain unresolved. Cyclic guanosine monophosphate (cGMP) is one of the main second messengers that mediate smooth muscle vasodilation and alterations in cGMP signaling could, therefore, be one mechanism by which skeletal muscle perfusion is impaired with advancing age. The current study aimed to evaluate the effect of inhibiting the main enzyme involved in cGMP degradation, phosphodiesterase 5 (PDE5), on blood flow and O2 delivery in contracting skeletal muscle of young and older humans. A group of young (23 ± 1 years) and a group of older (72 ± 2 years) male human subjects performed submaximal knee-extensor exercise in a control setting and following intake of the highly selective PDE5 inhibitor sildenafil. Sildenafil increased leg O2 delivery (6–9%) and leg O2 uptake (10–12%) at all three exercise intensities in older but not young subjects. The increase in leg O2 delivery with sildenafil in the older subjects correlated with the increase in leg O2 uptake (r2 = 0.843). These findings suggest an insufficient O2 delivery to the contracting skeletal muscle of aged individuals and that reduced cGMP availability is a novel mechanism underlying impaired skeletal muscle perfusion with advancing age. PMID:26272735

The effect of topical arnica on muscle pain.

PubMed

Adkison, Julie D; Bauer, David W; Chang, Terence

2010-10-01

The herb Arnica montana, in topical formulations, has been reputed to decrease bruising and muscle pain. This claim has been inadequately and incompletely addressed. To determine whether topical A. montana cream could decrease subjective leg pain following calf raises. Secondary outcomes were effects on ankle range of motion and muscle tenderness. A randomized, double-blind, placebo-controlled trial was conducted in 53 subjects. Active range of motion was measured in both ankles, and then a series of calf-raises were completed according to a standardized protocol. Each participant received 2 tubes of cream, 1 with active arnica and 1 with placebo. The creams were applied to the lower legs immediately after the exercise, and again at 24 and 48 hours postexercise according to the "RIGHT" or "LEFT" labels. At 48 hours postexercise, subjects had their ankle range of motion and muscle tenderness measured. Subjects used the analog scale to rate pain in each leg at baseline, 24 hours, 48 hours, and 72 hours. No significant differences in pain scores were seen before exercise (arnica: 0.07 vs placebo: 0.09, p = 0.32). Pain scores on legs treated with arnica were higher than scores on those receiving placebo 24 hours after exercise (3.04 vs 2.36, respectively; p < 0.005). Pain scores on day 3 (arnica: 3.44 vs placebo: 3.20, p = 0.66) and day 4 (arnica: 2.36 vs placebo: 2.31, p = 0.62) were not significantly different. There was no difference in muscle tenderness (arnica: 1.05 vs placebo: 1.05, p = 1.0). Ankle range of motion did not differ significantly on either day 1 (arnica: 64.70 degrees vs placebo: 66.15, p = 0.352 or day 3 (arnica: 63.32 degrees vs placebo: 65.94, p = 0.058). Rather than decreasing leg pain, arnica was found to increase leg pain 24 hours after eccentric calf exercises. This effect did not extend to the 48-hour measurement.

Haemodynamics of aerobic and resistance blood flow restriction exercise in young and older adults.

PubMed

Staunton, Craig A; May, Anthony K; Brandner, Christopher R; Warmington, Stuart A

2015-11-01

Light-load blood flow restriction exercise (BFRE) may provide a novel training method to limit the effects of age-related muscle atrophy in older adults. Therefore, the purpose of this study was to compare the haemodynamic response to resistance and aerobic BFRE between young adults (YA; n = 11; 22 ± 1 years) and older adults (OA; n = 13; 69 ± 1 years). On two occasions, participants completed BFRE or control exercise (CON). One occasion was leg press (LP; 20 % 1-RM) and the other was treadmill walking (TM; 4 km h(-1)). Haemodynamic responses (HR, Q, SV and BP) were recorded during baseline and exercise. At baseline, YA and OA were different for some haemodynamic parameters (e.g. BP, SV). The relative responses to BFRE were similar between YA and OA. Blood pressures increased more with BFRE, and also for LP over TM. Q increased similarly for BFRE and CON (in both LP and TM), but with elevated HR and reduced SV (TM only). While BFR conferred slightly greater haemodynamic stress than CON, this was lower for walking than leg-press exercise. Given similar response magnitudes between YA and OA, these data support aerobic exercise being a more appropriate BFRE for prescription in older adults that may contribute to limiting the effects of age-related muscle atrophy.

Quantifying kinematic differences between land and water during squats, split squats, and single-leg squats in a healthy population.

PubMed

Severin, Anna C; Burkett, Brendan J; McKean, Mark R; Wiegand, Aaron N; Sayers, Mark G L

2017-01-01

Aquatic exercises can be used in clinical and sporting disciplines for both rehabilitation and sports training. However, there is limited knowledge on the influence of water immersion on the kinematics of exercises commonly used in rehabilitation and fitness programs. The aim of this study was to use inertial sensors to quantify differences in kinematics and movement variability of bodyweight squats, split squats, and single-leg squats performed on dry land and whilst immersed to the level of the greater trochanter. During two separate testing sessions, 25 active healthy university students (22.3±2.9 yr.) performed ten repetitions of each exercise, whilst tri-axial inertial sensors (100 Hz) recorded their trunk and lower body kinematics. Repeated-measures statistics tested for differences in segment orientation and speed, movement variability, and waveform patterns between environments, while coefficient of variance was used to assess differences in movement variability. Between-environment differences in segment orientation and speed were portrayed by plotting the mean difference ±95% confidence intervals (CI) throughout the tasks. The results showed that the depth of the squat and split squat were unaffected by the changed environment while water immersion allowed for a deeper single leg squat. The different environments had significant effects on the sagittal plane orientations and speeds for all segments. Water immersion increased the degree of movement variability of the segments in all exercises, except for the shank in the frontal plane, which showed more variability on land. Without compromising movement depth, the aquatic environment induces more upright trunk and shank postures during squats and split squats. The aquatic environment allows for increased squat depth during the single-leg squat, and increased shank motions in the frontal plane. Our observations therefore support the use of water-based squat tasks for rehabilitation as they appear to improve the technique without compromising movement depth.

Quantifying kinematic differences between land and water during squats, split squats, and single-leg squats in a healthy population

PubMed Central

2017-01-01

Aquatic exercises can be used in clinical and sporting disciplines for both rehabilitation and sports training. However, there is limited knowledge on the influence of water immersion on the kinematics of exercises commonly used in rehabilitation and fitness programs. The aim of this study was to use inertial sensors to quantify differences in kinematics and movement variability of bodyweight squats, split squats, and single-leg squats performed on dry land and whilst immersed to the level of the greater trochanter. During two separate testing sessions, 25 active healthy university students (22.3±2.9 yr.) performed ten repetitions of each exercise, whilst tri-axial inertial sensors (100 Hz) recorded their trunk and lower body kinematics. Repeated-measures statistics tested for differences in segment orientation and speed, movement variability, and waveform patterns between environments, while coefficient of variance was used to assess differences in movement variability. Between-environment differences in segment orientation and speed were portrayed by plotting the mean difference ±95% confidence intervals (CI) throughout the tasks. The results showed that the depth of the squat and split squat were unaffected by the changed environment while water immersion allowed for a deeper single leg squat. The different environments had significant effects on the sagittal plane orientations and speeds for all segments. Water immersion increased the degree of movement variability of the segments in all exercises, except for the shank in the frontal plane, which showed more variability on land. Without compromising movement depth, the aquatic environment induces more upright trunk and shank postures during squats and split squats. The aquatic environment allows for increased squat depth during the single-leg squat, and increased shank motions in the frontal plane. Our observations therefore support the use of water-based squat tasks for rehabilitation as they appear to improve the technique without compromising movement depth. PMID:28767683

Surface Electromyographic Activity of the Abdominal Muscles During Pelvic-Tilt and Abdominal-Hollowing Exercises

PubMed Central

Drysdale, Cheri L.; Earl, Jennifer E.

2004-01-01

Objective: To investigate surface electromyographic (EMG) activity of the rectus abdominus and external oblique abdominus muscles during pelvic-tilt and abdominal-hollowing exercises performed in different positions. Design and Setting: 2 × 3 (exercise by position) within-subjects design with repeated measures on both factors. All testing was performed in a university laboratory. Subjects: Twenty-six healthy, active young adult females. Measurements: Surface EMG activity was recorded from the left and right rectus abdominus and external oblique muscles while the 2 exercises (pelvic tilt and abdominal hollowing) were performed in different positions (standard, legs supported, and legs unsupported). The standard position was supine in the crook-lying position, the supported position was with hips and knees flexed to 90° and legs supported on a platform, and the unsupported position was with hips and knees flexed to 90° without external support. Peak EMG activity was normalized to a maximum voluntary isometric contraction for each muscle. Results: For the rectus abdominus, there was an interaction between position and activity. Abdominal hollowing produced significantly less activity than the pelvic tilt in all positions. The difference between the 2 exercises with the legs unsupported was of a greater magnitude than the other 2 positions. For the external obliques, there was significantly lower activity during the abdominal hollowing compared with the pelvic tilting. The greatest muscle activity occurred with the legs-unsupported position during both exercises. Conclusions: Abdominal-hollowing exercises produced less rectus abdominus and external oblique activity than pelvic-tilting exercises. Abdominal hollowing may be performed with minimal activation of the large global abdominal muscles. PMID:15085209

Surface Electromyographic Activity of the Abdominal Muscles During Pelvic-Tilt and Abdominal-Hollowing Exercises.

PubMed

Drysdale, Cheri L.; Earl, Jennifer E.; Hertel, Jay

2004-03-01

OBJECTIVE: To investigate surface electromyographic (EMG) activity of the rectus abdominus and external oblique abdominus muscles during pelvic-tilt and abdominal-hollowing exercises performed in different positions. DESIGN AND SETTING: 2 x 3 (exercise by position) within-subjects design with repeated measures on both factors. All testing was performed in a university laboratory. SUBJECTS: Twenty-six healthy, active young adult females. MEASUREMENTS: Surface EMG activity was recorded from the left and right rectus abdominus and external oblique muscles while the 2 exercises (pelvic tilt and abdominal hollowing) were performed in different positions (standard, legs supported, and legs unsupported). The standard position was supine in the crook-lying position, the supported position was with hips and knees flexed to 90 degrees and legs supported on a platform, and the unsupported position was with hips and knees flexed to 90 degrees without external support. Peak EMG activity was normalized to a maximum voluntary isometric contraction for each muscle. RESULTS: For the rectus abdominus, there was an interaction between position and activity. Abdominal hollowing produced significantly less activity than the pelvic tilt in all positions. The difference between the 2 exercises with the legs unsupported was of a greater magnitude than the other 2 positions. For the external obliques, there was significantly lower activity during the abdominal hollowing compared with the pelvic tilting. The greatest muscle activity occurred with the legs-unsupported position during both exercises. CONCLUSIONS: Abdominal-hollowing exercises produced less rectus abdominus and external oblique activity than pelvic-tilting exercises. Abdominal hollowing may be performed with minimal activation of the large global abdominal muscles.

Effects of graded exercise-induced dehydration and rehydration on circulatory markers of oxidative stress across the resting and exercising human leg.

PubMed

Laitano, Orlando; Kalsi, Kameljit Kaur; Pearson, James; Lotlikar, Makra; Reischak-Oliveira, Alvaro; González-Alonso, José

2012-05-01

Exercise in the heat enhances oxidative stress markers in the human circulation, but the contribution of active skeletal muscle and the influence of hydration status remain unknown. To address this question, we measured leg exchange of glutathione (GSH), glutathione disulfide (GSSG), superoxide dismutase activity (SOD) and isoprostanes in seven males at rest and during submaximal one-legged knee extensor exercise in the following four conditions: (1) control euhydration (0% reduction in body mass), (2) mild-dehydration (2%), (3) moderate-dehydration (3.5%), (4) rehydration (0%). In all resting and control exercise conditions, a net GSH uptake was observed across the leg. In contrast, a significant leg release of GSH into the circulation (-354 ± 221 μmol/min, P < 0.05) was observed during exercise with moderate-dehydration, which was still present following full rehydration (-206 ± 122 μmol/min, P < 0.05). During exercise, mild and moderate-dehydration decreased both femoral venous erythrocyte SOD activity (195 ± 6 vs. 180 ± 5 U/L, P < 0.05) and plasma isoprostanes (30 ± 1.1 vs. 25.9 ± 1.3 pg/L, P < 0.05), but during rehydration these were not different from control. In conclusion, these findings suggest that active skeletal muscles release GSH into the circulation under moderate dehydration and subsequent rehydration, possibly to enhance the antioxidant defense.

Recovery From Exercise-Induced Muscle Damage: Cold-Water Immersion Versus Whole-Body Cryotherapy.

PubMed

Abaïdia, Abd-Elbasset; Lamblin, Julien; Delecroix, Barthélémy; Leduc, Cédric; McCall, Alan; Nédélec, Mathieu; Dawson, Brian; Baquet, Georges; Dupont, Grégory

2017-03-01

To compare the effects of cold-water immersion (CWI) and whole-body cryotherapy (WBC) on recovery kinetics after exercise-induced muscle damage. Ten physically active men performed single-leg hamstring eccentric exercise comprising 5 sets of 15 repetitions. Immediately postexercise, subjects were exposed in a randomized crossover design to CWI (10 min at 10°C) or WBC (3 min at -110°C) recovery. Creatine kinase concentrations, knee-flexor eccentric (60°/s) and posterior lower-limb isometric (60°) strength, single-leg and 2-leg countermovement jumps, muscle soreness, and perception of recovery were measured. The tests were performed before and immediately, 24, 48, and 72 h after exercise. Results showed a very likely moderate effect in favor of CWI for single-leg (effect size [ES] = 0.63; 90% confidence interval [CI] = -0.13 to 1.38) and 2-leg countermovement jump (ES = 0.68; 90% CI = -0.08 to 1.43) 72 h after exercise. Soreness was moderately lower 48 h after exercise after CWI (ES = -0.68; 90% CI = -1.44 to 0.07). Perception of recovery was moderately enhanced 24 h after exercise for CWI (ES = -0.62; 90% CI = -1.38 to 0.13). Trivial and small effects of condition were found for the other outcomes. CWI was more effective than WBC in accelerating recovery kinetics for countermovement-jump performance at 72 h postexercise. CWI also demonstrated lower soreness and higher perceived recovery levels across 24-48 h postexercise.

Effect of a lateral step-up exercise protocol on quadriceps and lower extremity performance.

PubMed

Worrell, T W; Borchert, B; Erner, K; Fritz, J; Leerar, P

1993-12-01

Closed kinetic chain exercises have been promoted as more functional and more appropriate than open kinetic chain exercises. Limited research exists demonstrating the effect of closed kinetic chain exercise on quadriceps and lower extremity performance. The purpose of this study was to determine the effect of a lateral step-up exercise protocol on isokinetic quadriceps peak torque and the following lower extremity activities: 1) leg press, 2) maximal step-up repetitions with body weight plus 25%, 3) hop for distance, and 4) 6-m timed hop. Twenty subjects participated in a 4-week training period, and 18 subjects served as controls. For the experimental group, a repeated measure ANOVA comparing pretest and posttest values revealed significant improvements in the leg press (p < or = .05), step-ups (p < or = .05), hop for distance (p < or = .05), and hop for time (p < or = .05) and no significant increase in isokinetic quadriceps peak torque (p > or = .05). Over the course of the training period, weight used for the step-up exercise increased (p < or = .05), repetitions decreased (p < or = .05), and step-up work did not change (p > or = .05). For the control group, no significant change (p > or = .05) occurred in any variable. The inability of the isokinetic dynamometer to detect increases in quadriceps performance is important because the isokinetic values are frequently used as criteria for return to functional activities. We conclude that closed kinetic chain testing and exercise provide additional means to assess and rehabilitate the lower extremity.

Exercise performance in patients with peripheral arterial disease who have different types of exertional leg pain.

PubMed

Gardner, Andrew W; Montgomery, Polly S; Afaq, Azhar

2007-07-01

This study compared the exercise performance of patients with peripheral arterial disease (PAD) who have different types of exertional leg pain. Patients with PAD were classified into one of four groups according to the San Diego Claudication Questionnaire: intermittent claudication (n = 406), atypical exertional leg pain causing patients to stop (n = 125), atypical exertional leg pain in which patients were able to continue walking (n = 81), and leg pain on exertion and rest (n = 103). Patients were assessed on the primary outcome measures of ankle-brachial index (ABI), treadmill exercise measures, and ischemic window. All patients experienced leg pain consistent with intermittent claudication during a standardized treadmill test. The mean (+/- SD) initial claudication distance (ICD) was similar (P = .642) among patients with intermittent claudication (168 +/- 160 meters), atypical exertional leg pain causing patients to stop (157 +/- 130 meters), atypical exertional leg pain in which patients were able to continue walking (180 +/- 149 meters), and leg pain on exertion and rest (151 +/- 136 meters). The absolute claudication distance (ACD) was similar (P = .648) in the four respective groups (382 +/- 232, 378 +/- 237, 400 +/- 245, and 369 +/- 236 meters). Similarly, the ischemic window, expressed as the area under the curve (AUC) after treadmill exercise, was similar (P = .863) in these groups (189 +/- 137, 208 +/- 183, 193 +/- 143, and 199 +/- 119 AUC). PAD patients with different types of exertional leg pain, all limited by intermittent claudication during a standardized treadmill test, were remarkably similar in ICD, ACD, and ischemic window. Thus, the presence of ambulatory symptoms should be of primary clinical concern in evaluating PAD patients regardless of whether they are consistent with classic intermittent claudication.

Inflammatory gene changes associated with the repeated-bout effect.

PubMed

Hubal, Monica J; Chen, Trevor C; Thompson, Paul D; Clarkson, Priscilla M

2008-05-01

This study proposed that attenuated expression of inflammatory factors is an underlying mechanism driving the repeated-bout effect (rapid adaptation to eccentric exercise). We investigated changes in mRNA levels and protein localization of inflammatory genes after two bouts of muscle-lengthening exercise. Seven male subjects performed two bouts of lower body exercise (separated by 4 wk) in which one leg performed 300 eccentric-concentric actions, and the contralateral leg performed 300 concentric actions only. Vastus lateralis biopsies were collected at 6 h, and strength was assessed at baseline and at 0, 3, and 5 days after exercise. mRNA levels were measured via semiquantitative RT-PCR for the following genes: CYR61, HSP40, HSP70, IL1R1, TCF8, ZFP36, CEBPD, and MCP1. Muscle functional adaptation was demonstrated via attenuated strength loss (16% less, P = 0.04) at 5 days after bout 2 compared with bout 1 in the eccentrically exercised leg. mRNA expression of three of the eight genes tested was significantly elevated in the eccentrically exercised leg from bout 1 to bout 2 (+3.9-fold for ZFP36, +2.3-fold for CEBPD, and +2.6-fold for MCP1), while all eight mRNA levels were unaffected by bout in the concentrically exercised leg. Immunohistochemistry further localized the protein of one of the elevated factors [monocyte chemoattractant protein-1 (MCP1)] within the tissue. MCP1 colocalized with resident macrophage and satellite cell populations, suggesting that alterations in cytokine signaling between these cell populations may play a role in muscle adaptation to exercise. Contrary to our hypothesis, several inflammatory genes were transcriptionally upregulated (rather than attenuated) after a repeated exercise bout, potentially indicating a role for these genes in the adaptation process.

Automated Management of Exercise Intervention at the Point of Care: Application of a Web-Based Leg Training System

PubMed Central

2015-01-01

Background Recent advances in information and communication technology have prompted development of Web-based health tools to promote physical activity, the key component of cardiac rehabilitation and chronic disease management. Mobile apps can facilitate behavioral changes and help in exercise monitoring, although actual training usually takes place away from the point of care in specialized gyms or outdoors. Daily participation in conventional physical activities is expensive, time consuming, and mostly relies on self-management abilities of patients who are typically aged, overweight, and unfit. Facilitation of sustained exercise training at the point of care might improve patient engagement in cardiac rehabilitation. Objective In this study we aimed to test the feasibility of execution and automatic monitoring of several exercise regimens on-site using a Web-enabled leg training system. Methods The MedExercise leg rehabilitation machine was equipped with wireless temperature sensors in order to monitor its usage by the rise of temperature in the resistance unit (Δt°). Personal electronic devices such as laptop computers were fitted with wireless gateways and relevant software was installed to monitor the usage of training machines. Cloud-based software allowed monitoring of participant training over the Internet. Seven healthy participants applied the system at various locations with training protocols typically used in cardiac rehabilitation. The heart rates were measured by fingertip pulse oximeters. Results Exercising in home chairs, in bed, and under an office desk was made feasible and resulted in an intensity-dependent increase of participants’ heart rates and Δt° in training machine temperatures. Participants self-controlled their activities on smart devices, while a supervisor monitored them over the Internet. Individual Δt° reached during 30 minutes of moderate-intensity continuous training averaged 7.8°C (SD 1.6). These Δt° were used as personalized daily doses of exercise with automatic email alerts sent upon achieving them. During 1-week training at home, automatic notifications were received on 4.4 days (SD 1.8). Although the high intensity interval training regimen was feasible on-site, it was difficult for self- and remote management. Opportunistic leg exercise under the desk, while working with a computer, and training in bed while viewing television were less intensive than dosed exercise bouts, but allowed prolonged leg mobilization of 73.7 minutes/day (SD 29.7). Conclusions This study demonstrated the feasibility of self-control exercise training on-site, which was accompanied by online monitoring, electronic recording, personalization of exercise doses, and automatic reporting of adherence. The results suggest that this technology and its applications are useful for the delivery of Web-based exercise rehabilitation and cardiac training programs at the point of care. PMID:28582243

A randomised clinical trial of the efficacy of drop squats or leg extension/leg curl exercises to treat clinically diagnosed jumper's knee in athletes: pilot study

PubMed Central

Cannell, L; Taunton, J; Clement, D; Smith, C; Khan, K

2001-01-01

Objectives—To compare the therapeutic effect of two different exercise protocols in athletes with jumper's knee. Methods—Randomised clinical trial comparing a 12 week programme of either drop squat exercises or leg extension/leg curl exercises. Measurement was performed at baseline and after six and 12 weeks. Primary outcome measures were pain (visual analogue scale 1–10) and return to sport. Secondary outcome measures included quadriceps and hamstring moment of force using a Cybex II isokinetic dynamometer at 30°/second. Differences in pain response between the drop squat and leg extension/curl treatment groups were assessed by 2 (group) x 3 (time) analysis of variance. Two by two contingency tables were used to test differences in rates of return to sport. Analysis of variance (2 (injured versus non-injured leg) x 2 (group) x 3 (time)) was also used to determine differences for secondary outcome measures. Results—Over the 12 week intervention, pain diminished by 2.3 points (36%) in the leg extension/curl group and 3.2 points (57%) in the squat group. There was a significant main effect of both exercise protocols on pain (p<0.01) with no interaction effect. Nine of 10 subjects in the drop squat group returned to sporting activity by 12 weeks, but five of those subjects still had low level pain. Six of nine of the leg extension/curl group returned to sporting activity by 12 weeks and four patients had low level pain. There was no significant difference between groups in numbers returning to sporting activity. There were no differences in the change in quadriceps or hamstring muscle moment of force between groups. Conclusions—Progressive drop squats and leg extension/curl exercises can reduce the pain of jumper's knee in a 12 week period and permit a high proportion of patients to return to sport. Not all patients, however, return to sport by that time. Key Words: knee; patellar tendon; tendinopathy; tendinosis; eccentric strengthening; strength training PMID:11157465

Haemoglobin saturation during incremental arm and leg exercise.

PubMed Central

Powers, S. K.; Dodd, S.; Woodyard, J.; Beadle, R. E.; Church, G.

1984-01-01

There are few reports concerning the alterations in the percent of haemoglobin saturated with oxygen (%SO2) during non-steady state incremental exercise. Further, no data exist to describe the %SO2 changes during arm exercise. Therefore, the purpose of this study was made to assess the dynamic changes in %SO2 during incremental arm and leg work. Nine trained subjects (7 males and 2 females) performed incremental arm and leg exercise to exhaustion on an arm crank ergometer and a cycle ergometer, respectively. Ventilation and gas exchange measurements were obtained minute by minute via open circuit spirometry and changes in %SO2 were recorded via an ear oximeter. No significant difference (p greater than 0.05) existed between arm and leg work in end-tidal oxygen (PETO2), end-tidal carbon dioxide (PETCO2), or %SO2 when compared as a function of percent VO2 max. These results provide evidence that arterial O2 desaturation occurs in a similar fashion in both incremental arm and leg work with the greatest changes in %SO2 occurring at work rates greater than 70% VO2 max. PMID:6435715

Effect of bed rest and exercise on body balance

NASA Technical Reports Server (NTRS)

Haines, R. F.

1974-01-01

A battery of 11 body balance tests was administered to 7 men before and after 14 days of bedrest. Seven men who had not undergone bed rest served as controls. During bed rest, each subject underwent daily either isotonic, isometric, or no leg exercise. The results showed that, for the bed-rested no exercise, isotonic exercise, and isometric exercise groups, 2 weeks of bed rest produces significant body balance decrements on 3, 4, and 5 of the 11 tests, respectively. Daily leg exercise did not prevent the debilitating effects of bed rest on body balance. After bed rest, balance skill was relearned rapidly so that in most tests, performance had reached prebed-rest levels by the third recovery day. These data suggest that balance impairment is not due to loss of muscular strength in the legs but, perhaps, to a bed-rest-related change in the neurally coded information to postural control centers.

Effects of Concentric and Eccentric Muscle Actions on Serum Myostatin and Follistatin-Like Related Gene Levels

PubMed Central

Willoughby, Darryn S.; Taylor, Lemuel

2004-01-01

The present study determined the effects of concentric and eccentric muscle actions on the contents of serum myostatin and follistatin-like related gene (FLRG). Eight untrained males performed one exercise bout with each leg, separated by three weeks. One bout consisted of 7 sets of 10 repetitions of eccentric muscle actions of the knee extensors at 150% of the concentric 1-RM while the other bout consisted of 7 sets of 10 repetitions of concentric muscle actions at 75% 1-RM. The legs used and the bouts performed were randomized. Five days prior to each exercise bout, baseline measurements were taken for muscle strength. For both bouts, a venous blood sample was obtained immediately prior to exercise and again at 6, 24, and 48 hr post-exercise. Data were analyzed with 2 X 4 (bout x test) ANOVA (p < 0.05). Increases in serum myostatin and FLRG occurred with each exercise bout and, excluding 48 hr post-exercise, were significantly correlated to one another (p < 0.05). After eccentric exercise, peak increases of 68% and 50% (p < 0.05) were observed for myostatin and FLRG, respectively. Similar increases of 54% and 44% (p < 0.05) were observed after concentric muscle actions. There was no significant difference in expression of myostatin or FLRG as a function of muscle action type. Our results suggest that a single bout of exercise with either eccentric or concentric muscle actions appear to elicit a similar increase in serum myostatin and FLRG. Therefore, the type of muscle action may not be as much a mitigating factor for increasing serum myostatin and FLRG rather than the muscle action per se. Key Points Eccentric muscle actions do not preferentially increase serum myostatin. Increases in serum myostatin in response to eccentric muscle actions are associated with increase in serum FLRG. Increases in serum myostatin and FLRG in response to eccentric muscle actions are not correlated to serum cortisol. PMID:24624007

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

Electromyographic Analysis of Single-Leg, Closed Chain Exercises: Implications for Rehabilitation After Anterior Cruciate Ligament Reconstruction

PubMed Central

Beutler, Anthony I.; Cooper, Leslie W.; Kirkendall, Don T.; Garrett, William E.

2002-01-01

Objective: Many knee rehabilitation studies have examined open and closed kinetic chain exercises. However, most studies focus on 2-legged, closed chain exercise. The purpose of our study was to characterize 1-legged, closed chain exercise in young, healthy subjects. Subjects: Eighteen normal subjects (11 men, 7 women; age, 24.6 ± 1.6 years) performed unsupported, 1-legged squats and step-ups to approximately tibial height. Measurements: Knee angle data and surface electromyographic activity from the thigh muscles were recorded. Results: The maximum angle of knee flexion was 111 ± 23° for squats and 101 ± 16° for step-ups. The peak quadriceps activation was 201 ± 66% maximum voluntary isometric contraction, occurring at an angle of 96 ± 16° for squats. Peak quadriceps activation was 207 ± 50% maximum voluntary isometric contraction and occurred at 83 ± 12° for step-ups. Conclusions: The high and sustained levels of quadriceps activation indicate that 1-legged squats and step-ups would be effective in muscle rehabilitation. As functional, closed chain activities, they may also be protective of anterior cruciate ligament grafts. Because these exercises involve no weights or training equipment, they may prove more cost effective than traditional modes of rehabilitation. PMID:12937438

Superior mitochondrial adaptations in human skeletal muscle after interval compared to continuous single‐leg cycling matched for total work

PubMed Central

MacInnis, Martin J.; Zacharewicz, Evelyn; Martin, Brian J.; Haikalis, Maria E.; Skelly, Lauren E.; Tarnopolsky, Mark A.; Murphy, Robyn M.

2016-01-01

Key points A classic unresolved issue in human integrative physiology involves the role of exercise intensity, duration and volume in regulating skeletal muscle adaptations to training.We employed counterweighted single‐leg cycling as a unique within‐subject model to investigate the role of exercise intensity in promoting training‐induced increases in skeletal muscle mitochondrial content.Six sessions of high‐intensity interval training performed over 2 weeks elicited greater increases in citrate synthase maximal activity and mitochondrial respiration compared to moderate‐intensity continuous training matched for total work and session duration.These data suggest that exercise intensity, and/or the pattern of contraction, is an important determinant of exercise‐induced skeletal muscle remodelling in humans. Abstract We employed counterweighted single‐leg cycling as a unique model to investigate the role of exercise intensity in human skeletal muscle remodelling. Ten young active men performed unilateral graded‐exercise tests to measure single‐leg V˙O2, peak and peak power (W peak). Each leg was randomly assigned to complete six sessions of high‐intensity interval training (HIIT) [4 × (5 min at 65% W peak and 2.5 min at 20% W peak)] or moderate‐intensity continuous training (MICT) (30 min at 50% W peak), which were performed 10 min apart on each day, in an alternating order. The work performed per session was matched for MICT (143 ± 8.4 kJ) and HIIT (144 ± 8.5 kJ, P > 0.05). Post‐training, citrate synthase (CS) maximal activity (10.2 ± 0.8 vs. 8.4 ± 0.9 mmol kg protein−1 min−1) and mass‐specific [pmol O2•(s•mg wet weight)−1] oxidative phosphorylation capacities (complex I: 23.4 ± 3.2 vs. 17.1 ± 2.8; complexes I and II: 58.2 ± 7.5 vs. 42.2 ± 5.3) were greater in HIIT relative to MICT (interaction effects, P < 0.05); however, mitochondrial function [i.e. pmol O2•(s•CS maximal activity)−1] measured under various conditions was unaffected by training (P > 0.05). In whole muscle, the protein content of COXIV (24%), NDUFA9 (11%) and mitofusin 2 (MFN2) (16%) increased similarly across groups (training effects, P < 0.05). Cytochrome c oxidase subunit IV (COXIV) and NADH:ubiquinone oxidoreductase subunit A9 (NDUFA9) were more abundant in type I than type II fibres (P < 0.05) but training did not increase the content of COXIV, NDUFA9 or MFN2 in either fibre type (P > 0.05). Single‐leg V˙O2, peak was also unaffected by training (P > 0.05). In summary, single‐leg cycling performed in an interval compared to a continuous manner elicited superior mitochondrial adaptations in human skeletal muscle despite equal total work. PMID:27396440

Modeling the benefits of an artificial gravity countermeasure coupled with exercise and vibration

NASA Astrophysics Data System (ADS)

Goel, Rahul; Kaderka, Justin; Newman, Dava

2012-01-01

The current, system-specific countermeasures to space deconditioning have limited success with the musculoskeletal system in long duration missions. Artificial gravity (AG) that is produced by short radius centrifugation has been hypothesized as an effective countermeasure because it reintroduces an acceleration field in space; however, AG alone might not be enough stimuli to preserve the musculoskeletal system. A novel combination of AG coupled with one-legged squats on a vibrating platform may preserve muscle and bone in the lower limbs to a greater extent than the current exercise paradigm. The benefits of the proposed countermeasure have been analyzed through the development of a simulation platform. Ground reaction force data and motion data were collected using a motion capture system while performing one-legged and two-legged squats in 1-G. The motion was modeled in OpenSim, an open-source software, and inverse dynamics were applied in order to determine the muscle and reaction forces of lower limb joints. Vibration stimulus was modeled by adding a 20 Hz sinusoidal force of 0.5 body weight to the force plate data. From the numerical model in a 1-G acceleration field, muscle forces for quadriceps femoris, plantar flexors and glutei increased substantially for one-legged squats with vibration compared to one- or two-legged squats without vibration. Additionally, joint reaction forces for one-legged squats with vibration also increased significantly compared to two-legged squats with or without vibration. Higher muscle forces and joint reaction forces might help to stimulate muscle activation and bone modeling and thus might reduce musculoskeletal deconditioning. These results indicate that the proposed countermeasure might surpass the performance of the current space countermeasures and should be further studied as a method of mitigating musculoskeletal deconditioning.

The effects of neuromuscular exercise on medial knee joint load post-arthroscopic partial medial meniscectomy: 'SCOPEX', a randomised control trial protocol.

PubMed

Hall, Michelle; Hinman, Rana S; Wrigley, Tim V; Roos, Ewa M; Hodges, Paul W; Staples, Margaret; Bennell, Kim L

2012-11-27

Meniscectomy is a risk factor for knee osteoarthritis, with increased medial joint loading a likely contributor to the development and progression of knee osteoarthritis in this group. Therefore, post-surgical rehabilitation or interventions that reduce medial knee joint loading have the potential to reduce the risk of developing or progressing osteoarthritis. The primary purpose of this randomised, assessor-blind controlled trial is to determine the effects of a home-based, physiotherapist-supervised neuromuscular exercise program on medial knee joint load during functional tasks in people who have recently undergone a partial medial meniscectomy. 62 people aged 30-50 years who have undergone an arthroscopic partial medial meniscectomy within the previous 3 to 12 months will be recruited and randomly assigned to a neuromuscular exercise or control group using concealed allocation. The neuromuscular exercise group will attend 8 supervised exercise sessions with a physiotherapist and will perform 6 exercises at home, at least 3 times per week for 12 weeks. The control group will not receive the neuromuscular training program. Blinded assessment will be performed at baseline and immediately following the 12-week intervention. The primary outcomes are change in the peak external knee adduction moment measured by 3-dimensional analysis during normal paced walking and one-leg rise. Secondary outcomes include the change in peak external knee adduction moment during fast pace walking and one-leg hop and change in the knee adduction moment impulse during walking, one-leg rise and one-leg hop, knee and hip muscle strength, electromyographic muscle activation patterns, objective measures of physical function, as well as self-reported measures of physical function and symptoms and additional biomechanical parameters. The findings from this trial will provide evidence regarding the effect of a home-based, physiotherapist-supervised neuromuscular exercise program on medial knee joint load during various tasks in people with a partial medial meniscectomy. If shown to reduce the knee adduction moment, neuromuscular exercise has the potential to prevent the onset of osteoarthritis or slow its progression in those with early disease. Australian New Zealand Clinical Trials Registry reference: ACTRN12612000542897.

Analog Exercise Hardware to Implement a High Intensity Exercise Program During Bed Rest

NASA Technical Reports Server (NTRS)

Loerch, Linda; Newby, Nate; Ploutz-Snyder, Lori

2012-01-01

Background: In order to evaluate novel countermeasure protocols in a space flight analog prior to validation on the International Space Station (ISS), NASA's Human Research Program (HRP) is sponsoring a multi-investigator bedrest campaign that utilizes a combination of commercial and custom-made exercise training hardware to conduct daily resistive and aerobic exercise protocols. This paper will describe these pieces of hardware and how they are used to support current bedrest studies at NASA's Flight Analog Research Unit in Galveston, TX. Discussion: To implement candidate exercise countermeasure studies during extended bed rest studies the following analog hardware are being utilized: Stand alone Zero-Gravity Locomotion Simulator (sZLS) -- a custom built device by NASA, the sZLS allows bedrest subjects to remain supine as they run on a vertically-oriented treadmill (0-15 miles/hour). The treadmill includes a pneumatic subject loading device to provide variable body loading (0-100%) and a harness to keep the subject in contact with the motorized treadmill to provide a ground reaction force at their feet that is quantified by a Kistler Force Plate. Supine Cycle Ergometer -- a commercially available supine cycle ergometer (Lode, Groningen, Netherlands) is used for all cycle ergometer sessions. The ergometer has adjustable shoulder supports and handgrips to help stabilize the subject during exercise. Horizontal Squat Device (HSD) -- a custom built device by Quantum Fitness Corp (Stafford, TX), the HSD allows for squat exercises to be performed while lying in a supine position. The HSD can provide 0 to 600 pounds of force in selectable 5 lb increments, and allows hip translation in both the vertical and horizontal planes. Prone Leg Curl -- a commercially available prone leg curl machine (Cybex International Inc., Medway, MA) is used to complete leg curl exercises. Horizontal Leg Press -- a commercially available horizontal leg press (Quantum Fitness Corporation) is used for leg press and heel raise exercises. Minor modifications were made to the device including adding 200 lbs to the weight stack, raising the frame by 12 inches, making the footplate adjustable, and providing removable handles. Conclusion: A combination of novel and commercial exercise hardware are used to mimic the exercise hardware capabilities aboard the ISS, allowing scientific investigation of new countermeasure protocols in a space flight analog prior to flight validation

Association of age and physical exercise with bodyweight and body composition in Asian Chinese men.

PubMed

Goh, Victor H-H; Tong, Terry Y Y

2010-12-01

The present study sought to examine the association between physical exercise as a lifestyle habit with anthropometric parameters and body composition and aging in men. Intensity of exercise was scored as metabolic equivalent-min/week (MET-min/week) from data of the questionnaire, while anthropometric parameters and body composition were carried out by standard measuring instruments and dual-energy X-ray absorptiometry scanner, respectively. Age was associated with decreases in bodyweight, height, total lean mass and bone mass, but an increase in fat mass. The negative association of lean mass with age was predominantly due to the negative association of lean masses in the legs and arm, while the positive association of fat mass with age was primarily due to the positive association of fat masses in the trunk and abdomen. Exercise of intensity greater than 1000 MET-min/week was significantly associated with higher lean and bone masses and lower fat mass. The increase in lean mass was predominantly in the legs, while the decreases in fat mass were in the trunk and abdomen. The study showed that the high intensity of physical exercise, equivalent to greater than 1000 MET-min/week, is required to effect beneficial changes in the body composition. Hence, results from the study support the importance of promoting a lifestyle habit of exercise of sufficient intensity in order to mitigate the increase risks of sarcopenia and obesity and their attendant ill effects on health in men as they age.

Unilateral Muscle Overuse Causes Bilateral Changes in Muscle Fiber Composition and Vascular Supply

PubMed Central

Song, Yafeng; Forsgren, Sture; Liu, Jing-Xia; Yu, Ji-Guo; Stål, Per

2014-01-01

Unilateral strength training can cause cross-transfer strength effects to the homologous contralateral muscles. However, the impact of the cross-over effects on the muscle tissue is unclear. To test the hypothesis that unilateral muscle overuse causes bilateral alterations in muscle fiber composition and vascular supply, we have used an experimental rabbit model with unilateral unloaded overstrain exercise via electrical muscle stimulation (E/EMS). The soleus (SOL) and gastrocnemius (GA) muscles of both exercised (E) and contralateral non-exercised (NE) legs (n = 24) were morphologically analyzed after 1w, 3w and 6w of EMS. Non-exercised rabbits served as controls (n = 6). After unilateral intervention the muscles of both E and NE legs showed myositis and structural and molecular tissue changes that to various degrees mirrored each other. The fiber area was bilaterally smaller than in controls after 3w of E/EMS in both SOL (E 4420 and NE 4333 µm2 vs. 5183 µm2, p<0.05) and GA (E 3572 and NE 2983 µm2 vs. 4697 µm2, p<0.02) muscles. After 6w of E/EMS, the percentage of slow MyHCI fibers was lower than in controls in the NE legs of SOL (88.1% vs. 98.1%, p<0.009), while the percentage of fast MyHCIIa fibers was higher in the NE legs of GA (25.7% vs. 15.8%, p = 0.02). The number of capillaries around fibers in the E and NE legs was lower (SOL 13% and 15%, respectively, GA 25% and 23%, respectively, p<0.05) than in controls. The overall alterations were more marked in the fast GA muscle than in the slow SOL muscle, which on the other hand showed more histopathological muscle changes. We conclude that unilateral repetitive unloaded overuse exercise via EMS causes myositis and muscle changes in fiber type proportions, fiber area and fiber capillarization not only in the exercised leg, but also in the homologous muscles in the non-exercised leg. PMID:25545800

Warm-up Optimizes Postural Control but Requires Some Minutes of Recovery.

PubMed

Paillard, Thierry; Kadri, Mohamed Abdelhafid; Nouar, Merbouha Boulahbel; Noé, Frederic

2018-05-02

Paillard, T, Kadri, MA, Nouar, MB, and Noé, F. Warm-up optimizes postural control but requires some minutes of recovery. J Strength Cond Res XX(X): 000-000, 2018-The aim was to compare monopedal postural control between the dominant leg (D-Leg) and the nondominant leg (ND-Leg) in pre- and post-warm-up conditions. Thirty healthy male sports science students were evaluated before and after a warm-up exercise (12 minutes of pedaling with an incremental effort on a cycle ergometer with a controlled workload). Monopodal postural control was assessed for the D- and ND-Legs before and immediately, 2, 5, 10, and 15 minutes after the warm-up exercise, using a force platform and calculating the displacement velocity of the center of foot pressure on the mediolateral (COPML velocity) and anteroposterior (COPAP velocity) axes. No significant difference was observed between the D-Leg and ND-Leg for both COPML and COPAP velocity in all the periods. In comparison with pre-warm-up, COPML decreased after 15-minute and 10-minute recovery periods for the D-Leg and the ND-Leg, respectively (p < 0.05), whereas COPAP decreased after 10-minute and 15-minute recovery periods (p < 0.001; p < 0.01, respectively) for the D-Leg, and after a 10-minute recovery period for the ND-Leg (p < 0.001). The warm-up optimized monopedal postural control but did not make it possible to distinguish a difference between the D-Leg and the ND-Leg. Some minutes of recovery are required between the end of the whole-body warm-up exercise and the beginning of the postural test to optimize postural control. The optimal duration of recovery turns out to be about 10-15 minutes.

Body Composition, Neuromuscular Performance, and Mobility: Comparison Between Regularly Exercising and Inactive Older Women.

PubMed

Rava, Anni; Pihlak, Anu; Ereline, Jaan; Gapeyeva, Helena; Kums, Tatjana; Purge, Priit; Jürimäe, Jaak; Pääsuke, Mati

2017-01-01

The purpose of this study was to evaluate the differences in body composition, neuromuscular performance, and mobility in healthy, regularly exercising and inactive older women, and examine the relationship between skeletal muscle indices and mobility. Overall, 32 healthy older women participated. They were divided into groups according to their physical activity history as regularly exercising (n = 22) and inactive (n = 10) women. Body composition, hand grip strength, leg extensor muscle strength, rapid force development, power output, and mobility indices were assessed. Regularly exercising women had lower fat mass and higher values for leg extensor muscle strength and muscle quality, and also for mobility. Leg extensor muscle strength and power output during vertical jumping and appendicular lean mass per unit of body mass were associated with mobility in healthy older women. It was concluded that long-term regular exercising may have beneficial effects on body composition and physical function in older women.

Acute Exercise Improves Mood and Motivation in Young Men with ADHD Symptoms.

PubMed

Fritz, Kathryn M; O'Connor, Patrick J

2016-06-01

Little is known about whether acute exercise affects signs or symptoms of attention deficit/hyperactivity disorder (ADHD) in adults. This experiment sought to determine the effects of a single bout of moderate-intensity leg cycling exercise on measures of attention, hyperactivity, mood, and motivation to complete mental work in adult men reporting elevated ADHD symptoms. A repeated-measures crossover experiment was conducted with 32 adult men (18-33 yr) with symptoms consistent with adult ADHD assessed by the Adult Self-Report Scale V1.1. Measures of attention (continuous performance task and Bakan vigilance task), motivation to perform the mental work (visual analog scale), lower leg physical activity (accelerometry), and mood (Profile of Mood States and Addiction Research Center Inventory amphetamine scale) were measured before and twice after a 20-min seated rest control or exercise condition involving cycling at 65% V˙O2peak. Condition (exercise vs rest) × time (baseline, post 1, and post 2) ANOVA was used to test the hypothesized exercise-induced improvements in all outcomes. Statistically significant condition-time interactions were observed for vigor (P < 0.001), amphetamine (P < 0.001), motivation (P = 0.027), and Profile of Mood States depression (P = 0.027), fatigue (P = 0.030), and confusion (P = 0.046) scales. No significant interaction effects were observed for leg hyperactivity, simple reaction time, or vigilance task performance (accuracy, errors, or reaction time). In young men reporting elevated symptoms of ADHD, a 20-min bout of moderate-intensity cycle exercise transiently enhances motivation for cognitive tasks, increases feelings of energy, and reduces feelings of confusion, fatigue, and depression, but this has no effect on the behavioral measures of attention or hyperactivity used.

Hormonal responses to resistance exercise during different menstrual cycle states.

PubMed

Nakamura, Yuki; Aizawa, Katsuji; Imai, Tomoko; Kono, Ichiro; Mesaki, Noboru

2011-06-01

To investigate the effect of menstrual cycle states on ovarian and anabolic hormonal responses to acute resistance exercise in young women. Eight healthy women (eumenorrhea; EM) and eight women with menstrual disorders including oligomenorrhea and amenorrhea (OAM) participated in this study. The EM group performed acute resistance exercises during the early follicular (EF) and midluteal (ML) phases, and the OAM group performed the same exercises. All subjects performed three sets each of lat pull-downs, leg curls, bench presses, leg extensions, and squats at 75%-80% of one-repetition maximum with a 1-min rest between sets. Blood samples were obtained before exercise, immediately after, 30 min after, and 60 min after the exercise. In the EM group, resting serum levels of estradiol and progesterone in the ML phase were higher than those in the EF phase and higher than those in the OAM group. Serum estradiol and progesterone in the ML phase increased after the exercise but did not change in the EF phase or in the OAM group. In contrast, resting levels of testosterone in the OAM group were higher than those in both the ML and EF phases of the EM group. After the exercise, serum growth hormone increased in both the ML and EF phases but did not change in the OAM group. The responses of anabolic hormones to acute resistance exercise are different among the menstrual cycle states in young women. Women with menstrual disturbances with low estradiol and progesterone serum levels have an attenuated anabolic hormone response to acute resistance exercise, suggesting that menstrual disorders accompanying low ovarian hormone levels may affect exercise-induced change in anabolic hormones in women.

Dynamic characteristics of T2*-weighted signal in calf muscles of peripheral artery disease during low-intensity exercise.

PubMed

Li, Zhijun; Muller, Matthew D; Wang, Jianli; Sica, Christopher T; Karunanayaka, Prasanna; Sinoway, Lawrence I; Yang, Qing X

2017-07-01

To evaluate the dynamic characteristics of T2* -weighted signal change in exercising skeletal muscle of healthy subjects and peripheral artery disease (PAD) patients under a low-intensity exercise paradigm. Nine PAD patients and nine age- and sex-matched healthy volunteers underwent a low-intensity exercise paradigm while magnetic resonance imaging (MRI) (3.0T) was obtained. T2*-weighted signal time-courses in lateral gastrocnemius, medial gastrocnemius, soleus, and tibialis anterior were acquired and analyzed. Correlations were performed between dynamic T2*-weighted signal and changes in heart rate, mean arterial pressure, leg pain, and perceived exertion. A significant signal decrease was observed during exercise in soleus and tibialis anterior of healthy participants (P = 0.0007-0.04 and 0.001-0.009, respectively). In PAD, negative signals were observed (P = 0.008-0.02 and 0.003-0.01, respectively) in soleus and lateral gastrocnemius during the early exercise stage. Then the signal gradually increased above the baseline in the lateral gastrocnemius during and after exercise in six of the eight patients who completed the study. This signal increase in patients' lateral gastrocnemius was significantly greater than in healthy subjects' during the later exercise stage (two-sample t-tests, P = 0.001-0.03). Heart rate and mean arterial pressure responses to exercise were significantly higher in PAD than healthy subjects (P = 0.036 and 0.008, respectively) and the patients experienced greater leg pain and exertion (P = 0.006 and P = 0.0014, respectively). During low-intensity exercise, there were different dynamic T2*-weighted signal behavior in the healthy and PAD exercising muscles. 2 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:40-48. © 2016 International Society for Magnetic Resonance in Medicine.

Intensity-level assessment of lower body plyometric exercises based on mechanical output of lower limb joints.

PubMed

Sugisaki, Norihide; Okada, Junichi; Kanehisa, Hiroaki

2013-01-01

The present study aimed to quantify the intensity of lower extremity plyometric exercises by determining joint mechanical output. Ten men (age, 27.3 ± 4.1 years; height, 173.6 ± 5.4 cm; weight, 69.4 ± 6.0 kg; 1-repetition maximum [1RM] load in back squat 118.5 ± 12.0 kg) performed the following seven plyometric exercises: two-foot ankle hop, repeated squat jump, double-leg hop, depth jumps from 30 and 60 cm, and single-leg and double-leg tuck jumps. Mechanical output variables (torque, angular impulse, power, and work) at the lower limb joints were determined using inverse-dynamics analysis. For all measured variables, ANOVA revealed significant main effects of exercise type for all joints (P < 0.05) along with significant interactions between joint and exercise (P < 0.01), indicating that the influence of exercise type on mechanical output varied among joints. Paired comparisons revealed that there were marked differences in mechanical output at the ankle and hip joints; most of the variables at the ankle joint were greatest for two-foot ankle hop and tuck jumps, while most hip joint variables were greatest for repeated squat jump or double-leg hop. The present results indicate the necessity for determining mechanical output for each joint when evaluating the intensity of plyometric exercises.

Metabolic and thermodynamic responses to dehydration-induced reductions in muscle blood flow in exercising humans

PubMed Central

González-Alonso, José; Calbet, José A L; Nielsen, Bodil

1999-01-01

The present study examined whether reductions in muscle blood flow with exercise-induced dehydration would reduce substrate delivery and metabolite and heat removal to and from active skeletal muscles during prolonged exercise in the heat. A second aim was to examine the effects of dehydration on fuel utilisation across the exercising leg and identify factors related to fatigue. Seven cyclists performed two cycle ergometer exercise trials in the heat (35°C; 61 ± 2% of maximal oxygen consumption rate, VO2,max), separated by 1 week. During the first trial (dehydration, DE), they cycled until volitional exhaustion (135 ± 4 min, mean ±s.e.m.), while developing progressive DE and hyperthermia (3.9 ± 0.3% body weight loss and 39.7 ± 0.2°C oesophageal temperature, Toes). On the second trial (control), they cycled for the same period of time maintaining euhydration by ingesting fluids and stabilising Toes at 38.2 ± 0.1°C. After 20 min of exercise in both trials, leg blood flow (LBF) and leg exchange of lactate, glucose, free fatty acids (FFA) and glycerol were similar. During the 20 to 135 ± 4 min period of exercise, LBF declined significantly in DE but tended to increase in control. Therefore, after 120 and 135 ± 4 min of DE, LBF was 0.6 ± 0.2 and 1.0 ± 0.3 l min−1 lower (P < 0.05), respectively, compared with control. The lower LBF after 2 h in DE did not alter glucose or FFA delivery compared with control. However, DE resulted in lower (P < 0.05) net FFA uptake and higher (P < 0.05) muscle glycogen utilisation (45%), muscle lactate accumulation (4.6-fold) and net lactate release (52%), without altering net glycerol release or net glucose uptake. In both trials, the mean convective heat transfer from the exercising legs to the body core ranged from 6.3 ± 1.7 to 7.2 ± 1.3 kJ min−1, thereby accounting for 35-40 % of the estimated rate of heat production (∼18 kJ min−1). At exhaustion in DE, blood lactate values were low whereas blood glucose and muscle glycogen levels were still high. Exhaustion coincided with high body temperature (∼40°C). In conclusion, the present results demonstrate that reductions in exercising muscle blood flow with dehydration do not impair either the delivery of glucose and FFA or the removal of lactate during moderately intense prolonged exercise in the heat. However, dehydration during exercise in the heat elevates carbohydrate oxidation and lactate production. A major finding is that more than one-half of the metabolic heat liberated in the contracting leg muscles is dissipated directly to the surrounding environment. The present results indicate that hyperthermia, rather than altered metabolism, is the main factor underlying the early fatigue with dehydration during prolonged exercise in the heat. PMID:10523424

Automated Management of Exercise Intervention at the Point of Care: Application of a Web-Based Leg Training System.

PubMed

Dedov, Vadim N; Dedova, Irina V

2015-11-23

Recent advances in information and communication technology have prompted development of Web-based health tools to promote physical activity, the key component of cardiac rehabilitation and chronic disease management. Mobile apps can facilitate behavioral changes and help in exercise monitoring, although actual training usually takes place away from the point of care in specialized gyms or outdoors. Daily participation in conventional physical activities is expensive, time consuming, and mostly relies on self-management abilities of patients who are typically aged, overweight, and unfit. Facilitation of sustained exercise training at the point of care might improve patient engagement in cardiac rehabilitation. In this study we aimed to test the feasibility of execution and automatic monitoring of several exercise regimens on-site using a Web-enabled leg training system. The MedExercise leg rehabilitation machine was equipped with wireless temperature sensors in order to monitor its usage by the rise of temperature in the resistance unit (Δt°). Personal electronic devices such as laptop computers were fitted with wireless gateways and relevant software was installed to monitor the usage of training machines. Cloud-based software allowed monitoring of participant training over the Internet. Seven healthy participants applied the system at various locations with training protocols typically used in cardiac rehabilitation. The heart rates were measured by fingertip pulse oximeters. Exercising in home chairs, in bed, and under an office desk was made feasible and resulted in an intensity-dependent increase of participants' heart rates and Δt° in training machine temperatures. Participants self-controlled their activities on smart devices, while a supervisor monitored them over the Internet. Individual Δt° reached during 30 minutes of moderate-intensity continuous training averaged 7.8°C (SD 1.6). These Δt° were used as personalized daily doses of exercise with automatic email alerts sent upon achieving them. During 1-week training at home, automatic notifications were received on 4.4 days (SD 1.8). Although the high intensity interval training regimen was feasible on-site, it was difficult for self- and remote management. Opportunistic leg exercise under the desk, while working with a computer, and training in bed while viewing television were less intensive than dosed exercise bouts, but allowed prolonged leg mobilization of 73.7 minutes/day (SD 29.7). This study demonstrated the feasibility of self-control exercise training on-site, which was accompanied by online monitoring, electronic recording, personalization of exercise doses, and automatic reporting of adherence. The results suggest that this technology and its applications are useful for the delivery of Web-based exercise rehabilitation and cardiac training programs at the point of care. ©Vadim N Dedov, Irina V Dedova. Originally published in JMIR Rehabilitation and Assistive Technology (http://rehab.jmir.org), 23.11.2015.

Prevention and treatment of exercise related leg pain in young soldiers; a review of the literature and current practice in the Dutch Armed Forces.

PubMed

Zimmermann, Wes O; Helmhout, P H; Beutler, A

2017-04-01

Overuse injuries of the leg are a common problem for young soldiers. This article reviews the literature concerning the prevention and treatment of exercise related leg pain in military settings and presents the latest developments in proposed mechanisms and treatments. Current practice and treatment protocols from the Dutch Armed Forces are reviewed, with an emphasis on the most prevalent conditions of medial tibial stress syndrome and chronic exertional compartment syndrome. The conclusion is that exercise related leg pain in the military is an occupational problem that deserves further study. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Muscle activity and spine load during anterior chain whole body linkage exercises: the body saw, hanging leg raise and walkout from a push-up.

PubMed

McGill, Stuart; Andersen, Jordan; Cannon, Jordan

2015-01-01

This study examined anterior chain whole body linkage exercises, namely the body saw, hanging leg raise and walkout from a push-up. Investigation of these exercises focused on which particular muscles were challenged and the magnitude of the resulting spine load. Fourteen males performed the exercises while muscle activity, external force and 3D body segment motion were recorded. A sophisticated and anatomically detailed 3D model used muscle activity and body segment kinematics to estimate muscle force, and thus sensitivity to each individual's choice of motor control for each task. Gradations of muscle activity and spine load characteristics were observed across tasks. On average, the hanging straight leg raise created approximately 3000 N of spine compression while the body saw created less than 2500 N. The hanging straight leg raise created the highest challenge to the abdominal wall (>130% MVC in rectus abdominis, 88% MVC in external oblique). The body saw resulted in almost 140% MVC activation of the serratus anterior. All other exercises produced substantial abdominal challenge, although the body saw did so in the most spine conserving way. These findings, along with consideration of an individual's injury history, training goals and current fitness level, should assist in exercise choice and programme design.

Arm blood flow and metabolism during arm and combined arm and leg exercise in humans

PubMed Central

Volianitis, S; Secher, N H

2002-01-01

The cardiovascular response to exercise with several groups of skeletal muscle suggests that work with the arms may decrease leg blood flow. This study evaluated whether intense exercise with the legs would have a similar effect on arm blood flow (Q̇arm) and O2 consumption (V̇O2,arm). Ten healthy male subjects (age 21 ± 1 year; mean ± S.D.) performed arm cranking at 80 % of maximum arm work capacity (A trial) and combined arm cranking with cycling at 60 % of maximum leg work capacity (A + L trial). The combined trial was a maximum effort for 5-6 min. Q̇arm measurement by thermodilution in the axilliary vein and arterial and venous blood samples permitted calculation of V̇O2,arm. During the combined trial, Q̇arm was reduced by 0.58 ± 0.25 l min−1 (19.1 ± 3.0 %, P < 0.05) from the value during arm cranking (3.00 ± 0.46 l min−1). The arterio-venous O2 difference increased from 122 ± 15 ml l−1 during the arm trial to 150 ± 21 ml l−1 (P < 0.05) during the combined trial. Thus, V̇O2,arm (0.45 ± 0.06 l min−1) was reduced by 9.6 ± 6.3 % (P < 0.05) and arm vascular conductance from 27 ± 4 to 23 ± 3 ml min−1 (mmHg)−1 (P < 0.05) as noradrenaline spillover from the arm increased from 7.5 ± 3.5 to 13.8 ± 4.2 nmol min−1 (P < 0.05). The data suggest that during maximal whole body exercise in humans, arm vasoconstriction is established to an extent that affects oxygen delivery to and utilisation by working skeletal muscles. PMID:12411540

Effects of whole-body vibration exercise on bone mineral content and density in thermally injured children.

PubMed

Edionwe, Joel; Hess, Cameron; Fernandez-Rio, Javier; Herndon, David N; Andersen, Clark R; Klein, Gordon L; Suman, Oscar E; Amonette, William E

2016-05-01

Loss of bone mass, muscle mass, and strength leads to significant disability in severely burned children. We assessed the effects of exercise combined with whole-body vibration (WBV) on bone mass, lean mass (LM), and muscle strength in children recovering from burns. Nineteen burned children (≥30% total body surface area [TBSA] burns) were randomly assigned to a 6-week exercise regimen either alone (EX; n=10) or in combination with a 6-week WBV training regimen (EX+WBV; n=9). WBV was performed concurrent to the exercise regimen for 5days/week on a vibrating platform. Dual-energy X-ray absorptiometry quantified bone mineral content (BMC), bone mineral density (BMD), and LM; knee extension strength was assessed using isokinetic dynamometry before and after training. Alpha was set at p<0.05. Both groups were similar in age, height, weight, TBSA burned, and length of hospitalization. Whole-body LM increased in the EX group (p=0.041) and trended toward an increase in the EX+WBV group (p=0.055). On the other hand, there were decreases in leg BMC for both groups (EX, p=0.011; EX+WBV, p=0.047), and in leg BMD for only the EX group (EX, p<0.001; EX+WBV, p=0.26). Truncal BMC decreased in only the EX group (EX, p=0.009; EX+WBV, p=0.61), while BMD decreased in both groups (EX, p<0.001; EX+WBV group, p<0.001). Leg strength increased over time in the EX group (p<0.001) and the EX+WBV group (p<0.001; between-group p=0.31). Exercise in combination with WBV may help attenuate regional bone loss in children recovering from burns. Studies are needed to determine the optimal magnitude, frequency, and duration of the vibration protocol, with attention to minimizing any potential interference with wound healing and graft closure. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

Effects of Whole-Body Vibration Exercise on Bone Mineral Content and Density in Thermally Injured Children

PubMed Central

Edionwe, Joel; Hess, Cameron; Fernandez-Rio, Javier; Herndon, David N.; Andersen, Clark R.; Klein, Gordon L.; Suman, Oscar E.; Amonette, William E.

2015-01-01

Background Loss of bone mass, muscle mass, and strength leads to significant disability in severely burned children. We assessed the effects of exercise combined with whole-body vibration (WBV) on bone mass, lean mass (LM), and muscle strength in children recovering from burns. Methods Nineteen burned children (≥30% total body surface area [TBSA] burns) were randomly assigned to a 6-week exercise regimen either alone (EX; n = 10) or in combination with a 6-week WBV training regimen (EX+WBV; n = 9). WBV was performed concurrent to the exercise regimen for 5 days/week on a vibrating platform. Dual-energy X-ray absorptiometry quantified bone mineral content (BMC), bone mineral density (BMD) and LM; knee extension strength was assessed using isokinetic dynamometry before and after training. Alpha was set at p < 0.05. Results Both groups were similar in age, height, weight, TBSA burned, and length of hospitalization. Whole-body LM increased in the EX group (p = 0.041) and trended toward an increase in the EX+WBV group (p = 0.055). On the other hand, there were decreases in leg BMC for both groups (EX, p = 0.011; EX+WBV, p = 0.047), and in leg BMD for only the EX group (EX, p < 0.001; EX+WBV, p = 0.26). Truncal BMC decreased in only the EX group (EX, p = 0.009; EX+WBV, p = 0.61), while BMD decreased in both groups (EX, p < 0.001; EX+WBV group, p < 0.001). Leg strength increased over time in the EX group (p < 0.001) and the EX+WBV group (p < 0.001; between-group P = 0.31). Conclusions Exercise in combination with WBV may help attenuate regional bone loss in children recovering from burns. Studies are needed to determine the optimal magnitude, frequency, and duration of the vibration protocol, with attention to minimizing any potential interference with wound healing and graft closure. PMID:26796240

Short-term effects on lower-body functional power development: weightlifting vs. vertical jump training programs.

PubMed

Tricoli, Valmor; Lamas, Leonardo; Carnevale, Roberto; Ugrinowitsch, Carlos

2005-05-01

Among sport conditioning coaches, there is considerable discussion regarding the efficiency of training methods that improve lower-body power. Heavy resistance training combined with vertical jump (VJ) training is a well-established training method; however, there is a lack of information about its combination with Olympic weightlifting (WL) exercises. Therefore, the purpose of this study was to compare the short-term effects of heavy resistance training combined with either the VJ or WL program. Thirty-two young men were assigned to 3 groups: WL = 12, VJ = 12, and control = 8. These 32 men participated in an 8-week training study. The WL training program consisted of 3 x 6RM high pull, 4 x 4RM power clean, and 4 x 4RM clean and jerk. The VJ training program consisted of 6 x 4 double-leg hurdle hops, 4 x 4 alternated single-leg hurdle hops, 4 x 4 single-leg hurdle hops, and 4 x 4 40-cm drop jumps. Additionally, both groups performed 4 x 6RM half-squat exercises. Training volume was increased after 4 weeks. Pretesting and posttesting consisted of squat jump (SJ) and countermovement jump (CMJ) tests, 10- and 30-m sprint speeds, an agility test, a half-squat 1RM, and a clean-and-jerk 1RM (only for WL). The WL program significantly increased the 10-m sprint speed (p < 0.05). Both groups, WL and VJ, increased CMJ (p < 0.05), but groups using the WL program increased more than those using the VJ program. On the other hand, the group using the VJ program increased its 1RM half-squat strength more than the WL group (47.8 and 43.7%, respectively). Only the WL group improved in the SJ (9.5%). There were no significant changes in the control group. In conclusion, Olympic WL exercises seemed to produce broader performance improvements than VJ exercises in physically active subjects.

Arm and Intensity-Matched Leg Exercise Induce Similar Inflammatory Responses.

PubMed

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

2016-06-01

The amount of active muscle mass can influence the acute inflammatory response to exercise, associated with reduced risk for chronic disease. This may affect those restricted to upper body exercise, for example, due to injury or disability. The purpose of this study was to compare the inflammatory responses for arm exercise and intensity-matched leg exercise. Twelve male individuals performed three 45-min constant load exercise trials after determination of peak oxygen uptake for arm exercise (V˙O2peak A) and cycling (V˙O2peak C): 1) arm cranking exercise at 60% V˙O2peak A, 2) moderate cycling at 60% V˙O2peak C, and 3) easy cycling at 60% V˙O2peak A. Cytokine, adrenaline, and flow cytometric analysis of monocyte subsets were performed before and up to 4 h postexercise. Plasma IL-6 increased from resting concentrations in all trials; however, postexercise concentrations were higher for arm exercise (1.73 ± 1.04 pg·mL) and moderate cycling (1.73 ± 0.95 pg·mL) compared with easy cycling (0.87 ± 0.41 pg·mL; P < 0.04). Similarly, the plasma IL-1ra concentration in the recovery period was higher for arm exercise (325 ± 139 pg·mL) and moderate cycling (316 ± 128 pg·mL) when compared with easy cycling (245 ± 77 pg·mL, P < 0.04). Arm exercise and moderate cycling induced larger increases in monocyte numbers and larger increases of the classical monocyte subset in the recovery period than easy cycling (P < 0.05). The postexercise adrenaline concentration was lowest for easy cycling (P = 0.04). Arm exercise and cycling at the same relative exercise intensity induces a comparable acute inflammatory response; however, cycling at the same absolute oxygen uptake as arm exercise results in a blunted cytokine, monocyte, and adrenaline response. Relative exercise intensity appears to be more important to the acute inflammatory response than modality, which is of major relevance for populations restricted to upper body exercise.

Intra-dialytic electrostimulation of leg extensors may improve exercise tolerance and quality of life in hemodialyzed patients.

PubMed

Dobsak, Petr; Homolka, Pavel; Svojanovsky, Jan; Reichertova, Anna; Soucek, Miroslav; Novakova, Marie; Dusek, Ladislav; Vasku, Jaromir; Eicher, Jean-Christophe; Siegelova, Jarmila

2012-01-01

Hemodialyzed (HD) patients with end-stage renal disease (ESRD) exhibit lower fitness as a consequence of chronic uremic changes that trigger various structural, metabolic, and functional abnormalities in skeletal muscles. The aim of this randomized study was to compare the effect of rehabilitation (RHB) training on a bicycle ergometer and electromyostimulation (EMS) of leg extensors in HD patients with ESRD. Thirty-two HD patients (18 men/14 women; mean age 61.1 ± 8.8 years) were randomized into three groups: (i) exercise training (ET; n = 11) on bicycle ergometer 2 × 20 min; (ii) EMS (n = 11) where stimulation (10 Hz) of leg extensors was applied for 60 min; and (iii) controls (CON; n = 10) without exercise. Exercising was performed between the 2nd and the 3rd hour of HD, three times a week, 20 weeks in total. Ergometric test was performed in order to evaluate peak workload (W(peak)), 6-min corridor walking test (CWT) to evaluate the distance walked, and dynamometry of leg extensors to assess muscle power (F(max)). Urea clearance was monitored and expressed as standard parameters: spKt/V, spKt/V equilibrated (spKt/V-e), and the urea removal ratio (URR). Quality of life (QoL) was assessed by the questionnaire SF-36. A significant increase of F(max) (P = 0.040 in group ET; P = 0.032 in group EMS), of 6-min CWT (P < 0.001 in ET group; P = 0.042 in EMS group), and of W(peak) (P = 0.041 in ET group) was observed. In both exercising groups, significant increase of spKt/V, spKt/V-e, and URR was found as compared with initial values (P < 0.05). In both exercising groups, highly significant changes in summarized mental functions were found (P = 0.001); in summarized physical components, significant improvement was observed in the ET group (P = 0.006). Intradialytic RHB showed comparable positive effects on functional parameters, urea clearance, and QoL. Intradialytic EMS might represent wide therapeutic possibility in the near future. © 2011, Copyright the Authors. Artificial Organs © 2011, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Contraction-Only Exercise Machine

NASA Technical Reports Server (NTRS)

Doerr, Donald F.; Maples, Arthur B.; Campbell, Craig M.

1992-01-01

Standard knee-extension machine modified so subject experiences force only when lifting leg against stack of weights. Exerts little force on leg while being lowered. Hydraulic cylinder and reservoir mounted on frame of exercise machine. Fluid flows freely from cylinder to reservoir during contraction (lifting) but in constricted fashion from reservoir to cylinder during extension (lowering).

Prevention of Potential Falls of Elderly Healthy Women: Gait Asymmetry

ERIC Educational Resources Information Center

Seo, Jung-suk; Kim, Sukwon

2014-01-01

The study attempted to see if exercise training would alleviate gait asymmetry between nondominant and dominant legs, thus, eliminate the likelihood of slips. The present study provided 18 older adults exercise training for eight weeks and evaluated kinematics and ground reaction forces (GRFs) in both legs. Participants were randomly assigned to…

16 Weeks of Training with the International Space Station Advanced Resistive Exercise Device (aRED) Is not Different than Training with Free Weights

NASA Technical Reports Server (NTRS)

Loehr, J. A.; Lee, S. M. C.; English, K. E.; Leach, M.; Bentley, J.; Nash, R.; Hagan, R. D.

2008-01-01

The advanced Resistive Exercise Device (aRED) is a resistive exercise system designed to maintain muscle mass and strength in microgravity by simulating free weight (FW) exercise. aRED utilizes vacuum cylinders and inertial flywheels to replicate the constant mass and inertial components, respectively, of FW exercise in normal gravity. PURPOSE: To compare the effectiveness of aRED and FW resistive exercise training in ambulatory subjects. METHODS: Untrained subjects were assigned to two groups, FW (6 males, 3 females) and aRED (8 males, 3 females), and performed squat (SQ), heel raise (HR), and deadlift (DL) exercises 3 d wk-1 for 16 wks. SQ, HR and DL strength (1RM) were measured using FW hardware pre-, mid- and post-training. Subjects participated in a periodized training protocol with the exercise prescription based on a percentage of 1RM. Thigh and lower leg muscle volume were assessed using Magnetic Resonance Imaging (MRI), and leg (LLM) and total body lean mass (BLM) were measured using Dual Energy X-ray Absorptiometry (DXA) pre- and post-training. RESULTS: SQ 1RM increased in both FW (48.9+/-6.1%) and aRED (31.2+/-3.8%) groups, and there was a greater training response in FW compared with aRED (p=0.01). HR and DL 1RM increased in FW (HR: 12.3+/-2.4%, DL: 23.3+/-4.4%) and aRED (HR: 18.0+/-1.6%, DL: 23.2+'-2.8%), but there were no differences between groups. Thigh muscle volume was greater following training in both groups (FW: 9.8+/-0.9%, aRED: 7.1+/-1.2%) but lower leg muscle volume increased only in the FW group (3.0+/-1.1%). Lean tissue mass increased in both FW (LLM: 3.9+/-1.1%, BLM: 2.5+/-0.7%) and aRED (LLM: 4.8+/-0.7%, BLM: 2.6 0.7%). There were no between group differences in muscle volume or lean mass in response to training. CONCLUSIONS: In general, the increase in muscle strength, muscle volume, and lean tissue mass when training with aRED was not different than when using the same training protocol with FW. The smaller increase in SQ 1RM in the aRED group may be the result of undersizing the aRED flywheels which were intended to mimic the inertial component of the SQ movement when performing FW exercises. However, the biomechanical differences observed in body position during the performance of the aRED SQ, which may have affected training and testing, cannot be excluded as a factor that may have affected SQ 1RM results. PRACTICAL APPLICATIONS: Improvements in muscle strength, muscle volume and lean mass similar to FW exercise training may be elicited using an alternative source of resistance during exercise training. The acceleration of a mass during resistive exercise may result in greater muscle tension when changing the direction of movement resulting in enhanced strength gains. Therefore, to maximize the benefits of resistive exercise, the inertial components of FW exercise should be considered during exercise selection and hardware design. ACKNOWLEDGEMENT: This investigation was supported by NASA-JSC s Exercise Countermeasures Project.

Using squat testing to predict training loads for lower-body exercises in elite karate athletes.

PubMed

Wong, Del P; Tan, Erik C H; Chaouachi, Anis; Carling, Christopher; Castagna, Carlo; Bloomfield, Jonathan; Behm, David G

2010-11-01

The purpose of this study was to determine the relationship between squat loads and 2 bilateral and 2 unilateral stepping lower-body exercises in predominantly unilateral movement elite athletes (Karate). Equations to predict loads for lower-body exercises based on the squat load were also determined. Fourteen male elite Karate athletes (age = 22.6 ± 1.2 years) performed 6 repetition maximum (RM) of the following free-weight bilateral exercises: back half squat, deadlift, leg press and unilateral stepping exercises, lunge; and step-up. Results showed that 6RM squat load was significantly (p < 0.001) correlated with deadlift (r = 0.86), leg press (r = 0.76), lunge (r = 0.86), and step-up (r = 0.92). Linear regression showed that the 6RM squat load was a significant predictor for deadlift, leg press, lunge, and step-up (R2 range from 0.57 to 0.85, p < 0.001). The following 6RM prediction equations were determined: (a) Deadlift = squat load (1.12)-16.60 kg, (b) Leg press = squat load (1.66) + 16.10 kg, (c) Lunge = squat load (0.61) + 9.39 kg, and (d) step-up = squat load (0.85)-10.36 kg. Coaches and fitness professionals can use the 6RM squat load as a time effective and accurate method to predict training loads for both bilateral and unilateral lower-body exercises with quadriceps as the prime mover. Load prescriptions for unilateral exercises should take into account the type of athletic population.

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.

Altered neuromuscular control of leg stiffness following soccer-specific exercise.

PubMed

Oliver, Jon L; De Ste Croix, Mark B A; Lloyd, Rhodri S; Williams, Craig A

2014-11-01

To examine changes to neuromuscular control of leg stiffness following 42 min of soccer-specific exercise. Ten youth soccer players, aged 15.8 ± 0.4 years, stature 1.73 ± 0.06 m and mass 59.8 ± 9.7 kg, hopped on a force plate at a self-selected frequency before and after simulated soccer exercise performed on a non-motorised treadmill. During hopping, muscle activity was measured using surface electromyography from four lower limb muscles and analysed to determine feedforward- and feedback-mediated activity, as well as co-contraction. There was a small, non-significant change in stiffness following exercise (26.6 ± 10.6 vs. 24.0 ± 7.0 kN m(-1), p > 0.05, ES = 0.25), with half the group increasing and half decreasing their stiffness. Changes in stiffness were significantly related to changes in centre of mass (CoM) displacement (r = 0.90, p < 0.01, extremely large correlation) but not changes in peak ground reaction force (r = 0.58, p > 0.05, large correlation). A number of significant relationships were observed between changes in stiffness and CoM displacement with changes in feedforward, feedback and eccentric muscle activity of the soleus and vastus lateralis muscles following exercise (r = 0.64-0.98, p < 0.05, large-extremely large correlations), but not with changes in co-contraction (r = 0.11-0.55, p > 0.05, small-large correlations). Following soccer-specific exercise individual changes in feedforward- and reflex-mediated activity of the soleus and vastus lateralis, and not co-contraction around the knee and ankle, modulate changes in CoM displacement and leg stiffness.

Electromyographic analysis of knee push up plus variations: what is the influence of the kinetic chain on scapular muscle activity?

PubMed

Maenhout, A; Van Praet, K; Pizzi, L; Van Herzeele, M; Cools, A

2010-11-01

First, to look for appropriate closed kinetic chain exercises to restore intramuscular imbalance between upper trapezius (UT) and serratus anterior (SA) in overhead athletes. Second, to determine the influence of using diagonal pattern muscle recruitment during knee push up plus (KPP) exercises on scapular electromyographic activity. Single group repeated-measures design. Controlled laboratory study. Thirty-two physically active individuals in good general health who did not have a history of neck and/or shoulder injury or surgery nor participated in high-level overhead sports or performed upper limb strength training for more than 5 h/week. Interventions Subjects performed the standard KPP and six variations. Electromyographic activity of the three trapezius parts and the SA. Four exercises with a low UT/SA can be selected for rehabilitation of intramuscular balance: standard KPP, KPP with homolateral leg extension, KPP with a wobble board and homolateral leg extension and one-handed KPP. The use of a wobble board during KPP exercises and performance on one hand has no influence on SA electromyographic activity. Heterolateral leg extension during KPP stimulates lower trapezius activity, whereas homolateral leg extension stimulates SA activity. In case of intramuscular scapular imbalance, some exercises are preferable over others because of their low UT/SA ratio. The use of a kinetic chain approach during KPP exercises influences scapular muscle activity.

Using Maximal Isometric Force to Determine the Optimal Load for Measuring Dynamic Muscle Power

NASA Technical Reports Server (NTRS)

Spiering, Barry A.; Lee, Stuart M. C.; Mulavara, Ajitkumar P.; Bentley, Jason R.; Nash, Roxanne E.; Sinka, Joseph; Bloomberg, Jacob J.

2009-01-01

Maximal power output occurs when subjects perform ballistic exercises using loads of 30-50% of one-repetition maximum (1-RM). However, performing 1-RM testing prior to power measurement requires considerable time, especially when testing involves multiple exercises. Maximal isometric force (MIF), which requires substantially less time to measure than 1-RM, might be an acceptable alternative for determining the optimal load for power testing. PURPOSE: To determine the optimal load based on MIF for maximizing dynamic power output during leg press and bench press exercises. METHODS: Twenty healthy volunteers (12 men and 8 women; mean +/- SD age: 31+/-6 y; body mass: 72 +/- 15 kg) performed isometric leg press and bench press movements, during which MIF was measured using force plates. Subsequently, subjects performed ballistic leg press and bench press exercises using loads corresponding to 20%, 30%, 40%, 50%, and 60% of MIF presented in randomized order. Maximal instantaneous power was calculated during the ballistic exercise tests using force plates and position transducers. Repeated-measures ANOVA and Fisher LSD post hoc tests were used to determine the load(s) that elicited maximal power output. RESULTS: For the leg press power test, six subjects were unable to be tested at 20% and 30% MIF because these loads were less than the lightest possible load (i.e., the weight of the unloaded leg press sled assembly [31.4 kg]). For the bench press power test, five subjects were unable to be tested at 20% MIF because these loads were less than the weight of the unloaded aluminum bar (i.e., 11.4 kg). Therefore, these loads were excluded from analysis. A trend (p = 0.07) for a main effect of load existed for the leg press exercise, indicating that the 40% MIF load tended to elicit greater power output than the 60% MIF load (effect size = 0.38). A significant (p . 0.05) main effect of load existed for the bench press exercise; post hoc analysis indicated that the effect of load on power output was: 30% > 40% > 50% = 60%. CONCLUSION: Loads of 40% and 30% of MIF elicit maximal power output during dynamic leg presses and bench presses, respectively. These findings are similar to those obtained when loading is based on 1-RM.

Single-leg hop testing following fatiguing exercise: reliability and biomechanical analysis.

PubMed

Augustsson, J; Thomeé, R; Lindén, C; Folkesson, M; Tranberg, R; Karlsson, J

2006-04-01

A fatiguing exercise protocol was combined with single-leg hop testing to improve the possibilities of evaluating the effects of training or rehabilitation interventions. In the first test-retest experiment, 11 healthy male subjects performed two trials of single-leg hops under three different test conditions: non-fatigued and following fatiguing exercise, which consisted of unilateral weight machine knee extensions at 80% and 50%, respectively, of 1 repetition maximum (1 RM) strength. Intraclass correlation coefficients ranged from 0.75 to 0.98 for different hop test conditions, indicating that all tests were reliable. For the second experiment, eight healthy male subjects performed the fatiguing exercise protocol to investigate how fatigue influences lower-extremity joint kinematics and kinetics during single-leg hops. Hip, knee and ankle joint angles, moments and powers, as well as ground-reaction forces were recorded with a six-camera, motion-capture system and a force platform. Recovery of hop performance following the fatiguing exercise was also measured. During the take-off for the single-leg hops, hip and knee flexion angles, generated powers for the knee and ankle joints, and ground-reaction forces decreased for the fatigued hop conditions compared with the non-fatigued condition (P<0.05). Compared with landing during the non-fatigued condition, hip moments and ground-reaction forces were lower for the fatigued hop conditions (P<0.05). The negative joint power was two to three times greater for the knee than for the hip and five to 10 times greater for the knee than for the ankle during landing for all test conditions (P<0.05). Most measured variables had recovered three minutes post-exercise. It is concluded that the fatiguing exercise protocol combined with single-leg hop testing was a reliable method for investigating functional performance under fatigued test conditions. Further, subjects utilized an adapted hop strategy, which employed less hip and knee flexion and generated powers for the knee and ankle joints during take-off, and less hip joint moments during landing under fatigued conditions. The large negative power values observed at the knee joint during the landing phase of the single-leg hop, during which the quadriceps muscle activates eccentrically, indicate that not only hop distance but also the ability to perform successful landings should be investigated when assessing dynamic knee function.

The effects of neuromuscular exercise on medial knee joint load post-arthroscopic partial medial meniscectomy: ‘SCOPEX’ a randomised control trial protocol

PubMed Central

2012-01-01

Background Meniscectomy is a risk factor for knee osteoarthritis, with increased medial joint loading a likely contributor to the development and progression of knee osteoarthritis in this group. Therefore, post-surgical rehabilitation or interventions that reduce medial knee joint loading have the potential to reduce the risk of developing or progressing osteoarthritis. The primary purpose of this randomised, assessor-blind controlled trial is to determine the effects of a home-based, physiotherapist-supervised neuromuscular exercise program on medial knee joint load during functional tasks in people who have recently undergone a partial medial meniscectomy. Methods/design 62 people aged 30–50 years who have undergone an arthroscopic partial medial meniscectomy within the previous 3 to 12 months will be recruited and randomly assigned to a neuromuscular exercise or control group using concealed allocation. The neuromuscular exercise group will attend 8 supervised exercise sessions with a physiotherapist and will perform 6 exercises at home, at least 3 times per week for 12 weeks. The control group will not receive the neuromuscular training program. Blinded assessment will be performed at baseline and immediately following the 12-week intervention. The primary outcomes are change in the peak external knee adduction moment measured by 3-dimensional analysis during normal paced walking and one-leg rise. Secondary outcomes include the change in peak external knee adduction moment during fast pace walking and one-leg hop and change in the knee adduction moment impulse during walking, one-leg rise and one-leg hop, knee and hip muscle strength, electromyographic muscle activation patterns, objective measures of physical function, as well as self-reported measures of physical function and symptoms and additional biomechanical parameters. Discussion The findings from this trial will provide evidence regarding the effect of a home-based, physiotherapist-supervised neuromuscular exercise program on medial knee joint load during various tasks in people with a partial medial meniscectomy. If shown to reduce the knee adduction moment, neuromuscular exercise has the potential to prevent the onset of osteoarthritis or slow its progression in those with early disease. Trial Registration Australian New Zealand Clinical Trials Registry reference: ACTRN12612000542897 PMID:23181415

Severe energy deficit upregulates leptin receptors, leptin signaling, and PTP1B in human skeletal muscle.

PubMed

Perez-Suarez, Ismael; Ponce-González, Jesús Gustavo; de La Calle-Herrero, Jaime; Losa-Reyna, Jose; Martin-Rincon, Marcos; Morales-Alamo, David; Santana, Alfredo; Holmberg, Hans-Christer; Calbet, Jose A L

2017-11-01

In obesity, leptin receptors (OBR) and leptin signaling in skeletal muscle are downregulated. To determine whether OBR and leptin signaling are upregulated with a severe energy deficit, 15 overweight men were assessed before the intervention (PRE), after 4 days of caloric restriction (3.2 kcal·kg body wt -1 ·day -1 ) in combination with prolonged exercise (CRE; 8 h walking + 45 min single-arm cranking/day) to induce an energy deficit of ~5,500 kcal/day, and following 3 days of control diet (isoenergetic) and reduced exercise (CD). During CRE, the diet consisted solely of whey protein ( n = 8) or sucrose ( n = 7; 0.8 g·kg body wt -1 ·day -1 ). Muscle biopsies were obtained from the exercised and the nonexercised deltoid muscles and from the vastus lateralis. From PRE to CRE, serum glucose, insulin, and leptin were reduced. OBR expression was augmented in all examined muscles associated with increased maximal fat oxidation. Compared with PRE, after CD, phospho-Tyr 1141 OBR, phospho-Tyr 985 OBR, JAK2, and phospho-Tyr 1007/1008 JAK2 protein expression were increased in all muscles, whereas STAT3 and phospho-Tyr 705 STAT3 were increased only in the arms. The expression of protein tyrosine phosphatase 1B (PTP1B) in skeletal muscle was increased by 18 and 45% after CRE and CD, respectively ( P < 0.05). Suppressor of cytokine signaling 3 (SOCS3) tended to increase in the legs and decrease in the arm muscles (ANOVA interaction: P < 0.05). Myosin heavy chain I isoform was associated with OBR protein expression ( r  = -0.75), phospho-Tyr 985 OBR ( r  = 0.88), and phospho-Tyr 705 STAT3/STAT3 ( r = 0.74). In summary, despite increased PTP1B expression, skeletal muscle OBR and signaling are upregulated by a severe energy deficit with greater response in the arm than in the legs likely due to SOCS3 upregulation in the leg muscles. NEW & NOTEWORTHY This study shows that the skeletal muscle leptin receptors and their corresponding signaling cascade are upregulated in response to a severe energy deficit, contributing to increase maximal fat oxidation. The responses are more prominent in the arm muscles than in the legs but partly blunted by whey protein ingestion and high volume of exercise. This occurs despite an increase of protein tyrosine phosphatase 1B protein expression, a known inhibitor of insulin and leptin signaling. Copyright © 2017 the American Physiological Society.

The effect of aroma stimulation during isotonic exercise on the rating of perceived exertion and blood fatigue factors of athletes with patellofemoral pain syndrome

PubMed Central

Kim, Sangsoo; Choo, JongHoo; Ju, Sungbum

2018-01-01

[Purpose] The purpose of this study is to examine the effect of aroma stimulation during isotonic exercise on the rating of perceived exertion (RPE) and the blood fatigue factors of athletes who have patellofemoral pain syndrome (PFPS). [Subjects and Methods] The research subjects were seven athletes in their twenties who suffer from PFPS. They were divided into a control group and an aroma stimulation group and performed isotonic exercises repeatedly. After exercising, the RPE and blood fatigue factors, including creatine phosphokinase (CPK), lactate dehydrogenase (LDH), and ammonia, were measured through blood sampling. [Results] The aroma stimulus group showed significantly lower RPE than the control group immediately after exercising, which included leg presses, leg curls, bicep curls, and leg extensions. Among the blood fatigue factors, the change in LDH indicated the effect of aroma stimulation. [Conclusion] We confirmed that aroma stimulation during isotonic exercise has the positive effect of reducing the RPE and blood fatigue factors, such as blood LDH, of the athletes with PFPS. PMID:29545683

A Pilot Study for Applying an Extravehicular Activity Exercise Prebreathe Protocol to the International Space Station

NASA Technical Reports Server (NTRS)

Woodruff, Kristin K.; Johnson, Anyika N.; Lee, Stuart M. C.; Gernhardt, Michael; Schneider, Suzanne M.; Foster, Philip P.

2000-01-01

Decompression sickness (DCS) is a serious risk to astronauts performing extravehicular activity (EVA). To reduce this risk, the addition of ten minutes of moderate exercise (75% VO2pk) during prebreathe has been shown to decrease the total prebreathe time from 4 to 2 hours and to decrease the incidence of DCS. The overall purpose of this pilot study was to develop an exercise protocol using flight hardware and an in-flight physical fitness cycle test to perform prebreathe exercise before an EVA. Eleven subjects volunteered to participate in this study. The first objective of this study was to compare the steady-state heart rate (HR) and oxygen consumption (VO2) from a submaximal arm and leg exercise (ALE) session with those predicted from a maximal ALE test. The second objective was to compare the steady-state HR and V02 from a submaximal elastic tube and leg exercise (TLE) session with those predicted from the maximal ALE test. The third objective involved a comparison of the maximal ALE test with a maximal leg-only (LE) test to conform to the in- flight fitness assessment test. The 75% VO2pk target HR from the LE test was significantly less than the target HR from the ALE test. Prescribing exercise using data from the maximal ALE test resulted in the measured submaximal values being higher than predicted VO2 and HR. The results of this pilot study suggest that elastic tubing is valid during EVA prebreathe as a method of arm exercise with the flight leg ergometer and it is recommended that prebreathe countermeasure exercise protocol incorporate this method.

Improvement in upper leg muscle strength underlies beneficial effects of exercise therapy in knee osteoarthritis: secondary analysis from a randomised controlled trial.

PubMed

Knoop, J; Steultjens, M P M; Roorda, L D; Lems, W F; van der Esch, M; Thorstensson, C A; Twisk, J W R; Bierma-Zeinstra, S M A; van der Leeden, M; Dekker, J

2015-06-01

Although exercise therapy is effective for reducing pain and activity limitations in patients with knee osteoarthritis (OA), the underlying mechanisms are unclear. This study aimed to evaluate if improvements in neuromuscular factors (i.e. upper leg muscle strength and knee proprioception) underlie the beneficial effects of exercise therapy in patients with knee OA. Secondary analyses from a randomised controlled trial, with measurements at baseline, 6 weeks, 12 weeks and 38 weeks. Rehabilitation centre. One hundred and fifty-nine patients diagnosed with knee OA. Exercise therapy. Changes in pain [numeric rating scale (NRS)] and activity limitations [Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function subscale and get-up-and-go test] during the study period. Independent variables were changes in upper leg muscle strength and knee joint proprioception (i.e. motion sense) during the study period. Longitudinal regression analyses (generalised estimating equation) were performed to analyse associations between changes in upper leg muscle strength and knee proprioception with changes in pain and activity limitations. Improved muscle strength was significantly associated with reductions in NRS pain {B coefficient -2.5 [95% confidence interval (CI) -3.7 to -1.4], meaning that every change of 1 unit of strength was linked to a change of -2.5 units of pain}, WOMAC physical function (-8.8, 95% CI -13.4 to -4.2) and get-up-and-go test (-1.7, 95% CI -2.4 to -1.0). Improved proprioception was not significantly associated with better outcomes of exercise therapy (P>0.05). Upper leg muscle strengthening is one of the mechanisms underlying the beneficial effects of exercise therapy in patients with knee OA. Copyright © 2014 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

Effect Of Leg Exercise On Vascular Volumes During Bed Rest

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Vernikos, J.; Wade, C. E.; Barnes, P. R.

1993-01-01

Report describes experiments on effects of no-exercise regimen and of two leg-exercise regimens on volumes of plasma, volumes of red blood cells, densities of bodies, and water balances of 19 men (32 to 42 years old) confined to minus 6 degrees-head-down bed rest for 30 days. Purpose of study to determine whether either or both exercise regimens maintain plasma volume and to relate levels of hypovolemia to body fluid balances. Results showed during bed rest, plasma volume maintained in isotomic group but not in other two groups, and no significant differences in body densities, body weights, or water balances among three groups. Concludes isotonic-exercise regimen better than isokinetic-exercise regimen for maintaining plasma volume during prolonged exposure to bed rest.

The impact of exercise and vitamin D supplementation on physical function in community-dwelling elderly individuals: A randomized trial.

PubMed

Aoki, Kana; Sakuma, Mayumi; Endo, Naoto

2018-04-25

We investigated the impact of exercise and vitamin D supplementation on physical function and locomotor dysfunction in community-dwelling elderly individuals. In total, 148 community-dwelling elderly individuals (aged ≥60 years) who were not taking osteoporosis medications participated in a 24-week intervention. The participants were randomly divided into an exercise group, vitamin D group, and exercise and vitamin D group. The participants and outcome-assessing staff were not blinded to group assignment. Exercise comprised three daily sets each of single-leg standing (1 min/leg/set) and squatting (5-6 repetitions/set); vitamin D supplementation was 1000 IU/day. Participants were contacted every 2 weeks to check on their condition and encourage continued participation. The primary outcome was lower limb muscle strength and mass; secondary outcomes were several physical function measurements, serum 25-hydroxyvitamin D levels, and results of a self-assessment questionnaire completed pre- and post-intervention. We analyzed data from 45, 42, and 43 participants in the exercise, vitamin D, and exercise and vitamin D groups, respectively, who completed the intervention. Locomotive syndrome, which involves reduced mobility due to locomotive organ impairment, was diagnosed in 99 participants (76.2%). Many physical function measurements improved in all groups. Lower limb muscle mass increased significantly in all three groups, with no significant differences between the groups in the degree of change. The average serum 25-hydroxyvitamin D of all vitamin D-supplemented participants increased from 28.1 ng/ml to 47.3 ng/ml after vitamin D supplementation. Both exercise and vitamin D supplementation independently improved physical function and increased muscle mass in community-dwelling elderly individuals. Moreover, the combination of exercise and vitamin D supplementation might further enhance these positive effects. UMIN Clinical Trial, UMIN000028229. Copyright © 2018. Published by Elsevier B.V.

A Comparison of the Physiology and Mechanics of Exercise in LBNP and Upright Gait

NASA Technical Reports Server (NTRS)

Boda, W. L.; Watenpaugh, D. E.; Ballard, R. E.; Chang, D.; Looft-Wilson, R.; Hargens, A. R.

1996-01-01

Bone, muscular strength, aerobic capacity, and normal fluid pressure gradients within the body are lost during bed rest and spaceflight. Lower Body Negative Pressure (LBNP) exercise may create musculoskeletal and cardiovascular strains equal to a greater than those experienced on Earth and elucidate some of the mechanisms for maintaining bone integrity. LBNP exercise simulates gravity during supine posture by using negative pressure to pull subjects inward against a treadmill generating footward forces and increasing transmural pressures. Footward forces are generated which equal the product of the pressure differential and the cross-sectional area of the LBNP waist seal. Subjects lie supine within the chamber with their legs suspended from one another via cuffs, bungee cords, and pulleys, such that each leg acts as a counterweight to the other leg during the gait cycle. The subjects then walk or run on a treadmill which is positioned vertically within the chamber. Supine orientation allows only footward force production due to the negative pressure within the chamber. The purpose of this study was to determine if the kinematics, kinetics, and metabolic rate during supine walking and slow running on a vertical treadmill within LBNP are similar to those on a treadmill in 1-g environment in an upright posture.

Preamputation evaluation of lower-limb skeletal muscle perfusion with H(2) (15)O positron emission tomography.

PubMed

Scremin, Oscar U; Figoni, Stephen F; Norman, Keith; Scremin, A M Erika; Kunkel, Charles F; Opava-Rutter, Dorene; Schmitter, Eric D; Bert, Alberto; Mandelkern, Mark

2010-06-01

To establish whether muscle blood flow (MBF) measurements with O-water positron emission tomography could reliably identify patients with critical limb ischemia and detect and quantify a distal deficit in skeletal MBF in these cases. O-water positron emission tomography scans were performed at rest or during unloaded ankle plantar and dorsiflexion exercise of the diseased leg in 17 subjects with leg ischemia or on a randomly selected leg of 18 age-matched healthy control subjects. TcPO2 was evaluated with Novametrix monitors and perfusion of skin topically heated to 44 degrees C and adjacent nonheated areas with a Moor Instruments laser Doppler imaging scanner. The enhancement of MBF induced by exercise was significantly lower in ischemic than in normal legs, and the sensitivity and specificity of this phenomenon were similar to those of laser Doppler imaging or TcPO2 in identifying ischemia subjects. In addition, the exercise MBF deficit was predominant at the distal-leg levels, indicating the ability of the technique to help determine the correct level of amputation. Skeletal MBF of legs with severe ischemia can be detected accurately with O-water positron emission tomography and could add valuable information about viability of skeletal muscle in the residual limb when deciding the level of an amputation.

Twelve-week combined resistance and aerobic training confers greater benefits than aerobic training alone in nondialysis CKD.

PubMed

Watson, Emma L; Gould, Douglas W; Wilkinson, Thomas J; Xenophontos, Soteris; Clarke, Amy L; Vogt, Barbara Perez; Viana, João L; Smith, Alice C

2018-06-01

There is a growing consensus that patients with chronic kidney disease (CKD) should engage in regular exercise, but there is a lack of formal guidelines. In this report, we determined whether combined aerobic and resistance exercise would elicit superior physiological gains, in particular muscular strength, compared with aerobic training alone in nondialysis CKD. Nondialysis patients with CKD stages 3b-5 were randomly allocated to aerobic exercise {AE, n = 21; 9 men; median age 63 [interquartile range (IQR) 58-71] yr; median estimated glomerular filtration rate (eGFR) 24 (IQR 20-30) ml·min -1 ·1.73 m -2 } or combined exercise [CE, n = 20, 9 men, median age 63 (IQR 51-69) yr, median eGFR 27 (IQR 22-32) ml·min -1 ·1.73 m -2 ], preceded by a 6-wk run-in control period. Patients then underwent 12 wk of supervised AE (treadmill, rowing, or cycling exercise) or CE training (as AE plus leg extension and leg press exercise) performed three times per week. Outcome assessments of knee extensor muscle strength, quadriceps muscle volume, exercise capacity, and central hemodynamics were performed at baseline, following the 6-wk control period, and at the end of the intervention. AE and CE resulted in significant increases in knee extensor strength of 16 ± 19% (mean ± SD; P = 0.001) and 48 ± 37% ( P < 0.001), respectively, which were greater after CE ( P = 0.02). AE and CE resulted in 5 ± 7% ( P = 0.04) and 9 ± 7% ( P < 0.001) increases in quadriceps volume, respectively ( P < 0.001), which were greater after CE ( P = 0.01). Both AE and CE increased distance walked in the incremental shuttle walk test [28 ± 44 m ( P = 0.01) and 32 ± 45 m ( P = 0.01), respectively]. In nondialysis CKD, the addition of resistance exercise to aerobic exercise confers greater increases in muscle mass and strength than aerobic exercise alone.

VO2 Max in Variable Type Exercise Among Well-Trained Upper Body Athletes.

ERIC Educational Resources Information Center

Seals, Douglas R.; Mullin, John P.

1982-01-01

The maximal oxygen consumption (VO2 max) of well-trained upper body athletes was compared to that of untrained individuals in four types of exercise: arm cranking, legs only cycling, graded treadmill running, and combined arm cranking and leg cycling. Results of the study showed that well-trained upper body athletes attained a significantly higher…

Immediate Effects of Smoking on Cardiorespiratory Responses During Dynamic Exercise: Arm Vs. Leg Ergometry.

PubMed

Chen, Chien-Liang; Tang, Jing-Shia; Li, Ping-Chia; Chou, Pi-Ling

2015-01-01

This study compared the immediate effects of smoking on cardiorespiratory responses to dynamic arm and leg exercises. This randomized crossover study recruited 14 college students. Each participant underwent two sets of arm-cranking (AC) and leg-cycling (LC) exercise tests. The testing sequences of the control trial (participants refrained from smoking for 8 h before testing) and the experimental trial (participants smoked two cigarettes immediately before testing) were randomly chosen. We observed immediate changes in pulmonary function and heart rate variability after smoking and before the exercise test. The participants then underwent graded exercise tests of their arms and legs until reaching exhaustion. We compared the peak work achieved and time to exhaustion during the exercise tests with various cardiorespiratory indices [i.e., heart rate, oxygen consumption (VO2), minute ventilation (VE)]. The differences between the smoking and control trials were calculated using paired t-tests. For the exercise test periods, VO2, heart rate, and VE values were calculated at every 10% increment of the maximal effort time. The main effects of the time and trial, as well as their trial-by-time (4 × 10) interaction effects on the outcome measures, were investigated using repeated measure ANOVA with trend analysis. 5 min after smoking, the participants exhibited reduced forced vital capacities and forced expiratory volumes in the first second (P < 0.05), in addition to elevated resting heart rates (P < 0.001). The high-frequency, low-frequency, and the total power of the heart rate variability were also reduced (P < 0.05) at rest. For the exercise test periods, smoking reduced the time to exhaustion (P = 0.005) and the ventilatory threshold (P < 0.05) in the LC tests, whereas no significant effects were observed in the AC tests. A trend analysis revealed a significant trial-by-time interaction effect for heart rate, VO2, and VE during the graded exercise test (all P < 0.001). Lower VO2 and VE levels were exhibited in the exercise response of the smoking trial than in those of the control LC trials, whereas no discernable inter-trial difference was observed in the AC trials. Moreover, the differences in heart rate and VE response between the LC and AC exercises were significantly smaller after the participants smoked. This study verified that smoking significantly decreased performance and cardiorespiratory responses to leg exercises. However, the negative effects of smoking on arm exercise performance were not as pronounced.

Influence of Isokinetic Strength Training of Unilateral Ankle on Ipsilateral One-legged Standing Balance of Adults

PubMed Central

Son, Sung Min; Kang, Kyung Woo; Lee, Na Kyung; Nam, Seok Hyun; Kwon, Jung Won; Kim, Kyoung

2013-01-01

[Purpose] The purpose of the current study was to investigate the changes in one-legged standing balance of the ipsilateral lower limb following unilateral isokinetic strength training. [Subjects and Methods] Thirty healthy adult volunteers were randomly assigned to either a training group or a control group, so that each group included 15 subjects. Subjects in the training group performed unilateral ankle isokinetic exercises of the dominant leg using the Biodex 3 PRO System for a period of four weeks. Ipsilateral one-legged standing balance was evaluated before and after the intervention with three stability indexes of balance using the Biodex System: Anterior-Posterior Stability Index (APSI), Medial-Lateral Stability Index (MLSI), and Overall Stability Index (OSI). [Results] Comparison of pre- and post-test data revealed significant improvements in strength values (dorsiflexion, plantarflexion, eversion, and inversion) and stability indexes (APSI, MLSI, OSI). [Conclusion] These results suggest that ankle strengthening exercise can be considered as a form of exercise that may assist individuals with improvement of balance. PMID:24259783

Patellofemoral Pain Syndrome

MedlinePlus

... But do this slowly, increasing the amount of time you do the sports activity a little at a time. Talk to ... 20 seconds. Do the exercise 6 to 10 times and then switch legs. Citations Management of Patellofemoral Pain Syndrome by S Dixit, M.D., ...

Gait, Balance, Leg Strength, and Sprint Speed After Bedrest with LBNP Exercise

NASA Technical Reports Server (NTRS)

Boda, Wanda L.; Watenbaugh, D. E.; Ballard, R. E.; Fortney, S. M.; Ertl, A. C.; Lee, S. M. C.; William, J. M.; Hargens, Alan R.

1997-01-01

Microgravity and bedrest (BR) result in similar physiological decrements such as loss of muscle mass, muscle strength and balance. Previous studies analyzing exercise within lower body negative pressure (LBNP) have found that gait is similar in LBNP on a vertical treadmill and overground exercise on a horizontal treadmill. Since treadmill exercise is known to increase muscular strength and endurance, we tested the hypothesis that LBNP exercise on a vertical treadmill would prevent or attenuate many of the physical decrements which occur during bedrest. Based on our positive results from diverse tests of post-BR function, we believe that exercise within LBNP is worth pursuing as a countermeasure for reducing the physical deterioration that occurs during bedrest and microgravity.

Effects of thermal stress and exercise on blood volume in humans

NASA Technical Reports Server (NTRS)

Harrison, M. H.

1985-01-01

The available experimental data base on the effects of exercise, posture and the environment (heat) on the blood volume, composition and concentration in humans is surveyed in depth to synthesize supportable conclusions. A large disparity is noted in the effective controls which were initiated in previous experimental conditions, resulting in contradictory findings regarding, e.g., hemoconcentrations and hemodilution in response to exercise. Comparisons between the results of exercise and of supine, seated and upright subjects has underscored the importance of gravity in hemoconcentration, particularly in the legs, and the generation of aldotestosterone. Hemoconcentration has been confirmed to increase with exercise in a seated or supine position. Exercise in a heated environment transfers cardiac output from core areas and reduces filtration efficiencies. Also, plasma volume increases, an action which cannot yet be associated with crystalloidal or colloidal influences on the osmotic behavior of cell walls.

Skeletal muscle mass and exercise performance in stable ambulatory patients with heart failure.

PubMed

Lang, C C; Chomsky, D B; Rayos, G; Yeoh, T K; Wilson, J R

1997-01-01

The purpose of this study was to determine whether skeletal muscle atrophy limits the maximal exercise capacity of stable ambulatory patients with heart failure. Body composition and maximal exercise capacity were measured in 100 stable ambulatory patients with heart failure. Body composition was assessed by using dual-energy X-ray absorption. Peak exercise oxygen consumption (VO2peak) and the anaerobic threshold were measured by using a Naughton treadmill protocol and a Medical Graphics CardioO2 System. VO2peak averaged 13.4 +/- 3.3 ml.min-1.kg-1 or 43 +/- 12% of normal. Lean body mass averaged 52.9 +/- 10.5 kg and leg lean mass 16.5 +/- 3.6 kg. Leg lean mass correlated linearly with VO2peak (r = 0.68, P < 0.01), suggesting that exercise performance is influences by skeletal muscle mass. However, lean body mass was comparable to levels noted in 1,584 normal control subjects, suggesting no decrease in muscle mass. Leg muscle mass was comparable to levels noted in 34 normal control subjects, further supporting this conclusion. These findings suggest that exercise intolerance in stable ambulatory patients with heart failure is not due to skeletal muscle atrophy.

The Effect of Smoking on Muscle Adaptation to Exercise Stress

DTIC Science & Technology

2011-12-01

adaptation in smokers: protein synthesis and degradation, regeneration, inflammation, and angiogenesis. We used a knee extension eccentric exercise...PDPK1 (PDK1) and PPP3CA, a subunit of calcineurin. PDPK1 is an upstream regulator of the AKT protein synthesis pathway that is activated during muscle...increasing muscle pain, cramping, and swelling of the leg. The subject reported no change in urine color. The subject was initially advised to attempt

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

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.

Decreased Hip, Lower Leg, and Humeral Fractures but Increased Forearm Fractures in Highly Active Individuals.

PubMed

Stattin, Karl; Hållmarker, Ulf; Ärnlöv, Johan; James, Stefan; Michaëlsson, Karl; Byberg, Liisa

2018-06-22

It is not known how physical exercise affects the risk of different types of fractures, especially in highly active individuals. To investigate this association, we studied a cohort of 118,204 men and 71,757 women who from 1991 to 2009 participated in Vasaloppet, a long-distance cross-country skiing race in Sweden, and 505,194 nonparticipants frequency-matched on sex, age, and county of residence from the Swedish population. Participants ranged from recreational exercisers to world-class skiers. Race participation, distance of race run, number of races participated in, and finishing time were used as proxies for physical exercise. Incident fractures from 1991 to 2010 were obtained from national Swedish registers. Over a median follow-up of 8.9 years, 53,175 fractures of any type, 2929 hip, 3107 proximal humerus, 11,875 lower leg, 11,733 forearm, and 2391 vertebral fractures occurred. In a Cox proportional hazard regression analysis using time-updated exposure and covariate information, participation in the race was associated with an increased risk of any type of fracture (hazard ratio [HR], 1.02; 95% CI, 1.00 to 1.05); forearm fractures had an HR, 1.11 with a 95% CI, 1.06 to 1.15. There was a lower risk of hip (HR, 0.75; 95% CI, 0.67 to 0.83), proximal humerus (HR, 0.90; 95% CI, 0.82 to 0.98), and lower leg fractures (HR, 0.93; 95% CI, 0.89 to 0.97), whereas the HR of vertebral fracture was 0.97 with a 95% CI, 0.88 to 1.07. Among participants, the risk of fracture was similar irrespective of race distance and number of races run. Participants close to the median finishing time had a lower risk of fracture compared with faster and slower participants. In summary, high levels of physical exercise were associated with a slightly higher risk of fractures of any type, including forearm fractures, but a lower risk of hip, proximal humerus, and lower leg fractures. © 2018 American Society for Bone and Mineral Research. © 2018 American Society for Bone and Mineral Research.

Supervised exercise training as an adjunct therapy for venous leg ulcers: a randomized controlled feasibility trial.

PubMed

Klonizakis, M; Tew, G A; Gumber, A; Crank, H; King, B; Middleton, G; Michaels, J A

2018-05-01

Venous leg ulcers (VLUs) are typically painful and heal slowly. Compression therapy offers high healing rates; however, improvements are not usually sustained. Exercise is a low-cost, low-risk and effective strategy for improving physical and mental health. Little is known about the feasibility and efficacy of supervised exercise training used in combination with compression therapy patients with VLUs. To assess the feasibility of a 12-week supervised exercise programme as an adjunct therapy to compression in patients with VLUs. This was a two-centre, two-arm, parallel-group, randomized feasibility trial. Thirty-nine patients with venous ulcers were recruited and randomized 1 : 1 either to exercise (three sessions weekly) plus compression therapy or compression only. Progress/success criteria included exercise attendance rate, loss to follow-up and patient preference. Baseline assessments were repeated at 12 weeks, 6 months and 1 year, with healing rate and time, ulcer recurrence and infection incidents documented. Intervention and healthcare utilization costs were calculated. Qualitative data were collected to assess participants' experiences. Seventy-two per cent of the exercise group participants attended all scheduled exercise sessions. No serious adverse events and only two exercise-related adverse events (both increased ulcer discharge) were reported. Loss to follow-up was 5%. At 12 months, median ulcer healing time was lower in the exercise group (13 vs. 34·7 weeks). Mean National Health Service costs were £813·27 for the exercise and £2298·57 for the control group. The feasibility and acceptability of both the supervised exercise programme in conjunction with compression therapy and the study procedures is supported. © 2017 The Authors. British Journal of Dermatology published by John Wiley & Sons Ltd on behalf of British Association of Dermatologists.

Effectiveness of various isometric exercises at improving bone strength in cortical regions prone to distal tibial stress fractures.

PubMed

Florio, C S

2018-06-01

A computational model was used to compare the local bone strengthening effectiveness of various isometric exercises that may reduce the likelihood of distal tibial stress fractures. The developed model predicts local endosteal and periosteal cortical accretion and resorption based on relative local and global measures of the tibial stress state and its surface variation. Using a multisegment 3-dimensional leg model, tibia shape adaptations due to 33 combinations of hip, knee, and ankle joint angles and the direction of a single or sequential series of generated isometric resultant forces were predicted. The maximum stress at a common fracture-prone region in each optimized geometry was compared under likely stress fracture-inducing midstance jogging conditions. No direct correlations were found between stress reductions over an initially uniform circular hollow cylindrical geometry under these critical design conditions and the exercise-based sets of active muscles, joint angles, or individual muscle force and local stress magnitudes. Additionally, typically favorable increases in cross-sectional geometric measures did not guarantee stress decreases at these locations. Instead, tibial stress distributions under the exercise conditions best predicted strengthening ability. Exercises producing larger anterior distal stresses created optimized tibia shapes that better resisted the high midstance jogging bending stresses. Bent leg configurations generating anteriorly directed or inferiorly directed resultant forces created favorable adaptations. None of the studied loads produced by a straight leg was significantly advantageous. These predictions and the insight gained can provide preliminary guidance in the screening and development of targeted bone strengthening techniques for those susceptible to distal tibial stress fractures. Copyright © 2018 John Wiley & Sons, Ltd.

Fall and balance outcomes after an intervention to promote leg strength, balance, and walking in people with diabetic peripheral neuropathy: "feet first" randomized controlled trial.

PubMed

Kruse, Robin L; Lemaster, Joseph W; Madsen, Richard W

2010-11-01

Weight-bearing exercise has been discouraged for people with diabetes mellitus and peripheral neuropathy (DM+PN). However, people with diabetes mellitus and insensate feet have an increased risk of falling. Lower-extremity exercise and balance training reduce fall risk in some older adults. It is unknown whether those with neuropathy experience similar benefits. As part of a study of the effects of weight-bearing exercise on foot ulceration in people with DM+PN, the effects of a lower-extremity exercise and walking intervention on balance, lower-extremity strength (force-generating capacity), and fall incidence were determined. Design The study was an observer-masked, 12-month randomized controlled trial. Part 1 of the intervention took place in physical therapy offices, and part 2 took place in the community. The participants were 79 people who were mostly sedentary, who had DM+PN, and who were randomly assigned to either a control group (n=38) or an intervention group (n=41). Intervention Part 1 included leg strengthening and balance exercises and a graduated, self-monitored walking program; part 2 included motivational telephone calls. Both groups received regular foot care, foot care education, and 8 sessions with a physical therapist. The measurements collected were strength, balance, and participant-reported falls for the year after enrollment. There were no statistically significant differences between the groups for falls during follow-up. At 12 months, there was a small increase in the amount of time that participants in the intervention group could stand on 1 leg with their eyes closed. No other strength or balance measurements differed between the groups. The study was designed to detect differences in physical activity, not falls. The intensity of the intervention was insufficient to improve strength and balance in this population. The training program had a minimal effect on participants' balance and lower-extremity strength. Increasing weight-bearing activity did not alter the rate of falling for participants in the intervention group relative to that for participants in the control group. People who are sedentary and who have DM+PN appear to be able to increase activity without increasing their rate of falling.

Human thermal responses during leg-only exercise in cold water.

PubMed

Golden, F S; Tipton, M J

1987-10-01

1. Exercise during immersion in cold water has been reported by several authors to accelerate the rate of fall of core temperature when compared with rates seen during static immersion. The nature of the exercise performed, however, has always been whole-body in nature. 2. In the present investigation fifteen subjects performed leg exercise throughout a 40 min head-out immersion in water at 15 degrees C. The responses obtained were compared with those seen when the subjects performed an identical static immersion. 3. Aural and rectal temperatures were found to fall by greater amounts during static immersion. 4. It is concluded that 'the type of exercise performed' should be included in the list of factors which affect core temperature during cold water immersion.

Evaluation of serum leaking enzymes and investigation into new biomarkers for exercise-induced muscle damage.

PubMed

Kanda, Kazue; Sugama, Kaoru; Sakuma, Jun; Kawakami, Yasuo; Suzuki, Katsuhiko

2014-01-01

This investigation determined whether existing muscle damage markers and organ damage markers respond to an acute eccentric exercise protocol and are associated with affected muscle symptoms. Nine healthy-young men completed one-leg calf-raise exercise with their right leg on a force plate. They performed 10 sets of 40 repetitions of exercise at 0.5 Hz with a load corresponding to half of their body weight, with 3 min rest between sets. The tenderness of medial gastrocnemius, lateral gastrocnemius and soleus, and the ankle active range of motion (ROM) were assessed before, immediately after, 24 h and 48 h, 72 h, 96 h and 168 h after exercise. Blood and urine were collected pre-exercise and 2 h, 4 h, 24 h, 48 h, 72 h and 96 h post-exercise. Serum was analyzed for creatine kinase (CK), aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and aldolase (ALD) activities. We also determined heart-type fatty acid-binding protein (H-FABP), intestinal-type fatty acid-binding protein (I-FABP) and liver-type fatty acid-binding protein (L-FABP), neutrophil gelatinase-associated lipocalin (NGAL), interleukin (IL)-17A, IL-23, nerve growth factor (NGF), soluble-Endothelial (sE)-selectin, s-Leukocyte (L)-selectin, s-Platelets (P)-selectin, and 8-isoprostane in plasma and urine. The tenderness of proximal and middle gastrocnemius increased significantly 72 h (p < 0.05, p < 0.01) after exercise. Ankle active ROM in dorsal flexion decreased significantly 48 h (p < 0.05) and 72 h (p < 0.01) after exercise. CK and ALD activities significantly increased at 72 h (p < 0.05) and remained elevated at 96 h (p < 0.01) postexercise compared to pre-exercise values. Also, ALD which showed relatively lower interindividual variability was significantly correlated with tenderness of middle gastrocnemius at 72 h. LDH activity significantly increased 96 h postexercise (p < 0.01), whereas the increase in AST and ALT activities 96 h post-exercise was not significantly different from pre-exercise values. There were no significant changes in FABPs, NGAL, IL-17A, IL-23, NGF, selectins and 8-isoprostanes in plasma and urine. In conclusion, calf-raise exercise induced severe local muscle damage symptoms which were accompanied by increases in both serum CK and ALD activities, but we could not detect any changes in examined markers of organ damage, inflammation and oxidative stress. Further research is needed to determine other more sensitive biomarkers and the underlying mechanisms of exercise-induced muscle damage.

Coordinated collagen and muscle protein synthesis in human patella tendon and quadriceps muscle after exercise

PubMed Central

Miller, Benjamin F; Olesen, Jens L; Hansen, Mette; Døssing, Simon; Crameri, Regina M; Welling, Rasmus J; Langberg, Henning; Flyvbjerg, Allan; Kjaer, Michael; Babraj, John A; Smith, Kenneth; Rennie, Michael J

2005-01-01

We hypothesized that an acute bout of strenuous, non-damaging exercise would increase rates of protein synthesis of collagen in tendon and skeletal muscle but these would be less than those of muscle myofibrillar and sarcoplasmic proteins. Two groups (n = 8 and 6) of healthy young men were studied over 72 h after 1 h of one-legged kicking exercise at 67% of maximum workload (Wmax). To label tissue proteins in muscle and tendon primed, constant infusions of [1-13C]leucine or [1-13C]valine and flooding doses of [15N] or [13C]proline were given intravenously, with estimation of labelling in target proteins by gas chromatography–mass spectrometry. Patellar tendon and quadriceps biopsies were taken in exercised and rested legs at 6, 24, 42 or 48 and 72 h after exercise. The fractional synthetic rates of all proteins were elevated at 6 h and rose rapidly to peak at 24 h post exercise (tendon collagen (0.077% h−1), muscle collagen (0.054% h−1), myofibrillar protein (0.121% h−1), and sarcoplasmic protein (0.134% h−1)). The rates decreased toward basal values by 72 h although rates of tendon collagen and myofibrillar protein synthesis remained elevated. There was no tissue damage of muscle visible on histological evaluation. Neither tissue microdialysate nor serum concentrations of IGF-I and IGF binding proteins (IGFBP-3 and IGFBP-4) or procollagen type I N-terminal propeptide changed from resting values. Thus, there is a rapid increase in collagen synthesis after strenuous exercise in human tendon and muscle. The similar time course of changes of protein synthetic rates in different cell types supports the idea of coordinated musculotendinous adaptation. PMID:16002437

Exercise tolerance during VO2max testing is a multifactorial psychobiological phenomenon.

PubMed

Midgley, Adrian W; Earle, Keith; McNaughton, Lars R; Siegler, Jason C; Clough, Peter; Earle, Fiona

2017-01-01

Fifty-nine men completed a VO 2max test and a questionnaire to establish reasons for test termination, perceived exercise reserve (difference between actual test duration and the duration the individual perceived could have been achieved if continued until physical limitation), and perception of verbal encouragement. Participants gave between 1 and 11 factors as reasons for test termination, including leg fatigue, various perceptions of physical discomfort, safety concerns, and achievement of spontaneously set goals. The two most common main reasons were leg fatigue and breathing discomfort, which were predicted by pre-to-post test changes in pulmonary function (p = 0.038) and explosive leg strength (p = 0.042; R 2  = 0.40). Median (interquartile range) perceived exercise reserve, was 45 (50) s. Two-thirds of participants viewed verbal encouragement positively, whereas one-third had a neutral or negative perception. This study highlights the complexity of exercise tolerance during VO 2max testing and more research should explore these novel findings.

Dual-cycle ergometry as an exercise modality during prebreathe with 100 percent oxygen

NASA Technical Reports Server (NTRS)

Heaps, Cristine L.; Fischer, Michele D.; Webb, James T.

1994-01-01

In an effort to reduce prebreathe time requirements prior to extravehicular activities and high-altitude flights, a combined arm and leg exercise task proposes to enhance denitrogenation by incorporation of both upper and lower body musculature at a moderately high work intensity during prebreathe with 100% oxygen. Preliminary findings indicated peak oxygen consumption (VO2peak) levels attained on the dual-cycle ergometer do not differ significantly from those levels attained on the treadmill. Eight male subjects were exercised to VO2peak using leg-only cycle ergometry and dual-cycle ergometry on separate days. Preliminary data during dual-cycle ergometry showed arm work equaling 30% of the leg workrate at each stage of the incremental test resulted in arm fatigue in several subjects and a reduced VO2peak compared to dual-cycle ergometry with arm work at 20%. Thus, the 20% workrate was used during the dual-cycle VO2peak trial. On a third experimental day, subjects performed a 10 minute exercise test at a workrate required to elicit 75% of VO2peak for each subject on the dual-cycle ergometer. Blood lactate response to the exercise was monitored as an objective measure of fatigue. Peak VO2 levels attained on the leg-only and the dual-cycle ergometry tasks were not significantly different. Blood lactate levels were significantly elevated following the dual-cycle ergometry at 75% VO2peak. However, lactate levels show the expected rate of decline during recovery and, as demonstrated in the literature, should return to baseline levels within 30 minutes following exercise cessation. Thus, dual-cycle ergometry at 75% VO2peak appears to be a valid exercise for use during prebreathe and should not contribute to fatigue during subsequent EVA's.

Maintenance of exercise-induced benefits in physical functioning and bone among elderly women.

PubMed

Karinkanta, S; Heinonen, A; Sievänen, H; Uusi-Rasi, K; Fogelholm, M; Kannus, P

2009-04-01

This study showed that about a half of the exercise-induced gain in dynamic balance and bone strength was maintained one year after cessation of the supervised high-intensity training of home-dwelling elderly women. However, to maintain exercise-induced gains in lower limb muscle force and physical functioning, continued training seems necessary. Maintenance of exercise-induced benefits in physical functioning and bone structure was assessed one year after cessation of 12-month randomized controlled exercise intervention. Originally 149 healthy women 70-78 years of age participated in the 12-month exercise RCT and 120 (81%) of them completed the follow-up study. Self-rated physical functioning, dynamic balance, leg extensor force, and bone structure were assessed. During the intervention, exercise increased dynamic balance by 7% in the combination resistance and balance-jumping training group (COMB). At the follow-up, a 4% (95% CI: 1-8%) gain compared with the controls was still seen, while the exercise-induced isometric leg extension force and self-rated physical functioning benefits had disappeared. During the intervention, at least twice a week trained COMB subjects obtained a significant 2% benefit in tibial shaft bone strength index compared to the controls. A half of this benefit seemed to be maintained at the follow-up. Exercise-induced benefits in dynamic balance and rigidity in the tibial shaft may partly be maintained one year after cessation of a supervised 12-month multi-component training in initially healthy elderly women. However, to maintain the achieved gains in muscle force and physical functioning, continued training seems necessary.

Exercise against lower body negative pressure as a countermeasure for cardiovascular and musculoskeletal deconditioning

NASA Astrophysics Data System (ADS)

Murthy, G.; Watenpaugh, D. E.; Ballard, R. E.; Hargens, A. R.

Exposure to lower body negative pressure (LBNP) with oral salt and water ingestion has been tested by astronauts as a countermeasure to prevent postflight orthostatic intolerance. Exercise is another countermeasure that astronauts commonly use during spaceflight to maintain musculoskeletal strength. We hypothesize that a novel combination of exercise and simultaneous exposure to lower body negative pressure during spaceflight will produce Earth-like musculoskeletal loads as well as cardiovascular stimuli to maintain adaptation to Earth's gravity. Results from recent studies indicate that leg exercise within a LBNP chamber against the suction force of 100 mmHg LBNP in horizontal-supine posture produces an equivalent, if not greater exercise stress compared to similar leg exercise in upright posture (without LBNP) against Earth's gravity. 12 Therefore, the concept of LBNP combined with exercise may prove to be a low cost and low mass technique to stress the cardiovascular and the musculoskeletal systems simultaneously.

Effects of Baseline Levels of Flexibility and Vertical Jump Ability on Performance Following Different Volumes of Static Stretching and Potentiating Exercises in Elite Gymnasts

PubMed Central

Donti, Olyvia; Tsolakis, Charilaos; Bogdanis, Gregory C.

2014-01-01

This study examined the effects of baseline flexibility and vertical jump ability on straight leg raise range of motion (ROM) and counter-movement jump performance (CMJ) following different volumes of stretching and potentiating exercises. ROM and CMJ were measured after two different warm-up protocols involving static stretching and potentiating exercises. Three groups of elite athletes (10 male, 14 female artistic gymnasts and 10 female rhythmic gymnasts) varying greatly in ROM and CMJ, performed two warm-up routines. One warm-up included short (15 s) static stretching followed by 5 tuck jumps, while the other included long static stretching (30 s) followed by 3x5 tuck jumps. ROM and CMJ were measured before, during and for 12 min after the two warm-up routines. Three-way ANOVA showed large differences between the three groups in baseline ROM and CMJ performance. A type of warm-up x time interaction was found for both ROM (p = 0.031) and CMJ (p = 0.016). However, all athletes, irrespective of group, responded in a similar fashion to the different warm-up protocols for both ROM and CMJ, as indicated from the lack of significant interactions for group (condition x group, time x group or condition x time x group). In the short warm-up protocol, ROM was not affected by stretching, while in the long warm-up protocol ROM increased by 5.9% ± 0.7% (p = 0.001) after stretching. Similarly, CMJ remained unchanged after the short warm-up protocol, but increased by 4.6 ± 0.9% (p = 0.012) 4 min after the long warm- up protocol, despite the increased ROM. It is concluded that the initial levels of flexibility and CMJ performance do not alter the responses of elite gymnasts to warm-up protocols differing in stretching and potentiating exercise volumes. Furthermore, 3 sets of 5 tuck jumps result in a relatively large increase in CMJ performance despite an increase in flexibility in these highly-trained athletes. Key Points The initial levels of flexibility and vertical jump ability have no effect on straight leg raise range of motion (ROM) and counter-movement jump performance (CMJ) of elite gymnasts following warm-up protocols differing in stretching and potentiating exercise volumes Stretching of the main leg muscle groups for only 15 s has no effect on ROM of elite gymnasts In these highly-trained athletes, one set of 5 tuck jumps during warm-up is not adequate to increase CMJ performance, while 3 sets of 5 tuck jumps result in a relatively large increase in CMJ performance (by 4.6% above baseline), despite a 5.9% increase in flexibility due to the 30 s stretching exercises PMID:24570613

Exercise reduces C-reactive protein and improves physical function in automotive workers with low back pain.

PubMed

Kim, Sang Kook; Jung, Ilho; Kim, Jae Hee

2008-06-01

Little is known about the effect of exercise on C-reactive protein (CRP) in patients with low back pain (LBP). The aim of the study was to investigate the effects of 8-week exercise intervention on CRP and physical function in automotive workers with LBP. Thirteen male workers (40 +/- 6 years) with LBP completed an 8-week multicomponent exercise intervention program which consisted of resistance training, swimming, stretching and hiking. Serum CRP concentration and physical functions were measured at baseline and after 8-week exercise intervention. Compared to baseline, CRP levels decreased by 38% (P = 0.005), back flexibility improved, isokinetic leg strengths increased (all P < 0.05), and back strength tended to increase. The results of the present study show that CRP levels decrease with exercise in subjects with LBP and physical function improves. This suggests that exercise-related decreases in inflammation in persons with LBP are associated with improvements in physical function.

Joint Kinetics and Kinematics During Common Lower Limb Rehabilitation Exercises.

PubMed

Comfort, Paul; Jones, Paul Anthony; Smith, Laura Constance; Herrington, Lee

2015-10-01

Unilateral body-weight exercises are commonly used to strengthen the lower limbs during rehabilitation after injury, but data comparing the loading of the limbs during these tasks are limited. To compare joint kinetics and kinematics during 3 commonly used rehabilitation exercises. Descriptive laboratory study. Laboratory. A total of 9 men (age = 22.1 ± 1.3 years, height = 1.76 ± 0.08 m, mass = 80.1 ± 12.2 kg) participated. Participants performed the single-legged squat, forward lunge, and reverse lunge with kinetic data captured via 2 force plates and 3-dimensional kinematic data collected using a motion-capture system. Peak ground reaction forces, maximum joint angles, and peak sagittal-joint moments. We observed greater eccentric and concentric peak vertical ground reaction forces during the single-legged squat than during both lunge variations (P ≤ .001). Both lunge variations demonstrated greater knee and hip angles than did the single-legged squat (P < .001), but we observed no differences between lunges (P > .05). Greater dorsiflexion occurred during the single-legged squat than during both lunge variations (P < .05), but we noted no differences between lunge variations (P = .70). Hip-joint moments were greater during the forward lunge than during the reverse lunge (P = .003) and the single-legged squat (P = .011). Knee-joint moments were greater in the single-legged squat than in the reverse lunge (P < .001) but not greater in the single-legged squat than in the forward lunge (P = .41). Ankle-joint moments were greater during the single-legged squat than during the forward lunge (P = .002) and reverse lunge (P < .001). Appropriate loading progressions for the hip should begin with the single-legged squat and progress to the reverse lunge and then the forward lunge. In contrast, loading progressions for the knee and ankle should begin with the reverse lunge and progress to the forward lunge and then the single-legged squat.

Effects of unilateral and bilateral plyometric training on power and jumping ability in women.

PubMed

Makaruk, Hubert; Winchester, Jason B; Sadowski, Jerzy; Czaplicki, Adam; Sacewicz, Tomasz

2011-12-01

Makaruk, H, Winchester, JB, Sadowski, J, Czaplicki, A, and Sacewicz, T. Effects of unilateral and bilateral plyometric training on power and jumping ability in women. J Strength Cond Res 25(12): 3311-3318, 2011-The purpose of this study was to examine the effects of unilateral and bilateral plyometric exercise on peak power and jumping performance during different stages of a 12-week training and detraining in women. Forty-nine untrained but physically active female college students were randomly assigned to 1 of 3 groups: unilateral plyometric group (n = 16), bilateral plyometric group (BLE; n = 18), and a control group (n = 15). Peak power and jumping ability were assessed by means of the alternate leg tests (10-second Wingate test and 5 alternate leg bounds), bilateral leg test (countermovement jump [CMJ]) and unilateral leg test (unilateral CMJ). Performance indicators were measured pretraining, midtraining, posttraining, and detraining. Differences between dependent variables were assessed with a 3 × 4 (group × time) repeated analysis of variance with Tukey's post hoc test applied where appropriate. Effect size was calculated to determine the magnitude of significant differences between the researched parameters. Only the unilateral plyometric training produced significant (p < 0.05) improvement in all tests from pretraining to midtraining, but there was no significant (p < 0.05) increase in performance indicators from midtraining to posttraining. The BLE group significantly (p < 0.05) improved in all tests from pretraining to posttraining and did not significantly (p > 0.05) decrease power and jumping ability in all tests during detraining. These results suggest that unilateral plyometric exercises produce power and jumping performance during a shorter period when compared to bilateral plyometric exercises but achieved performance gains last longer after bilateral plyometric training. Practitioners should consider the inclusion of both unilateral and bilateral modes of plyometric exercise to elicit rapid improvements and guard against detraining.

The role of active muscle mass in determining the magnitude of peripheral fatigue during dynamic exercise.

PubMed

Rossman, Matthew J; Garten, Ryan S; Venturelli, Massimo; Amann, Markus; Richardson, Russell S

2014-06-15

Greater peripheral quadriceps fatigue at the voluntary termination of single-leg knee-extensor exercise (KE), compared with whole-body cycling, has been attributed to confining group III and IV skeletal muscle afferent feedback to a small muscle mass, enabling the central nervous system (CNS) to tolerate greater peripheral fatigue. However, as task specificity and vastly differing systemic challenges may have complicated this interpretation, eight males were studied during constant workload trials to exhaustion at 85% of peak workload during single-leg and double-leg KE. It was hypothesized that because of the smaller muscle mass engaged during single-leg KE, a greater magnitude of peripheral quadriceps fatigue would be present at exhaustion. Vastus lateralis integrated electromyogram (iEMG) signal relative to the first minute of exercise, preexercise to postexercise maximal voluntary contractions (MVCs) of the quadriceps, and twitch-force evoked by supramaximal magnetic femoral nerve stimulation (Qtw,pot) quantified peripheral quadriceps fatigue. Trials performed with single-leg KE (8.1 ± 1.2 min; 45 ± 4 W) resulted in significantly greater peripheral quadriceps fatigue than double-leg KE (10 ± 1.3 min; 83 ± 7 W), as documented by changes in the iEMG signal (147 ± 24 vs. 85 ± 13%), MVC (-25 ± 3 vs. -12 ± 3%), and Qtw,pot (-44 ± 6 vs. -33 ± 7%), for single-leg and double-leg KE, respectively. Therefore, avoiding concerns over task specificity and cardiorespiratory limitations, this study reveals that a reduction in muscle mass permits the development of greater peripheral muscle fatigue and supports the concept that the CNS tolerates a greater magnitude of peripheral fatigue when the source of group III/IV afferent feedback is limited to a small muscle mass.

Feasibility and Preliminary Efficacy of a 10-Week Resistance and Aerobic Exercise Intervention During Neoadjuvant Chemoradiation Treatment in Rectal Cancer Patients.

PubMed

Singh, Favil; Galvão, Daniel A; Newton, Robert U; Spry, Nigel A; Baker, Michael K; Taaffe, Dennis R

2018-06-01

Neoadjuvant chemoradiation treatment (CRT) in rectal cancer patients is associated with a reduction in physical capacity, lean mass and increased fatigue. As a countermeasure to these treatment-related adverse effects, we examined the feasibility and preliminary efficacy of a 10-week exercise program during CRT. Ten rectal cancer patients (7 men, aged 27-70 years, body mass index = 26.4 ± 3.8 kg/m 2 ) receiving CRT undertook supervised resistance and aerobic exercise twice weekly. Assessments were undertaken pre- and post-intervention for upper and lower body muscle strength by 1-RM, muscle endurance, physical performance tests, body composition by dual X-ray absorptiometry, quality of life, and fatigue. There was a significant loss in appendicular skeletal muscle (-1.1 kg, P = .012), and fat mass (-0.8 kg, P = .029) following CRT. Despite the loss in skeletal muscle, leg press ( P = .030) and leg extension ( P = .046) strength improved by 27.2% and 22.7%, respectively, and leg press endurance by 76.7% ( P = .007). Changes in strength were accompanied by improved performance ( P < .05) in 6-m fast walking speed (6.9%) and dynamic balance as determined by the 6-m backwards walk (15.5%). There was minimal change in quality of life and fatigue, and no adverse events related to training. Exercise during neoadjuvant CRT appears to be feasible and well tolerated in rectal cancer patients and may enhance physical function while minimizing adverse changes in body composition and cancer-related fatigue. These initial findings need to be confirmed in randomized controlled trials.

Cardiovascular and Muscular Consequences of Work-Matched Interval-Type of Concentric and Eccentric Pedaling Exercise on a Soft Robot.

PubMed

Flück, Martin; Bosshard, Rebekka; Lungarella, Max

2017-01-01

Eccentric types of endurance exercise are an acknowledged alternative to conventional concentric types of exercise rehabilitation for the cardiac patient, because they reduce cardiorespiratory strain due to a lower metabolic cost of producing an equivalent mechanical output. The former contention has not been tested in a power- and work-matched situation of interval-type exercise under identical conditions because concentric and eccentric types of exercise pose specific demands on the exercise machinery, which are not fulfilled in current practice. Here we tested cardiovascular and muscular consequences of work-matched interval-type of leg exercise (target workload of 15 sets of 1-min bipedal cycles of knee extension and flexion at 30 rpm with 17% of maximal concentric power) on a soft robotic device in healthy subjects by concomitantly monitoring respiration, blood glucose and lactate, and power during exercise and recovery. We hypothesized that interval-type of eccentric exercise lowers strain on glucose-related aerobic metabolism compared to work-matched concentric exercise, and reduces cardiorespiratory strain to levels being acceptable for the cardiac patient. Eight physically active male subjects (24.0 years, 74.7 kg, 3.4 L O2 min -1 ), which power and endurance performance was extensively characterized, completed the study, finalizing 12 sets on average. Average performance was similar during concentric and eccentric exercise ( p = 0.75) but lower than during constant load endurance exercise on a cycle ergometer at 75% of peak aerobic power output (126 vs. 188 Watt) that is recommended for improving endurance capacity. Peak oxygen uptake (-17%), peak ventilation (-23%), peak cardiac output (-16%), and blood lactate (-37%) during soft robotic exercise were lower during eccentric than concentric exercise. Glucose was 8% increased after eccentric exercise when peak RER was 12% lower than during concentric exercise. Muscle power and RFD were similarly reduced after eccentric and concentric exercise. The results highlight that the deployed interval-type of eccentric leg exercise reduces metabolic strain of the cardiovasculature and muscle compared to concentric exercise, to recommended levels for cardio-rehabilitation (i.e., 50-70% of peak heart rate). Increases in blood glucose concentration indicate that resistance to contraction-induced glucose uptake after the deployed eccentric protocol is unrelated to muscle fatigue.

Cardiovascular and Muscular Consequences of Work-Matched Interval-Type of Concentric and Eccentric Pedaling Exercise on a Soft Robot

PubMed Central

Flück, Martin; Bosshard, Rebekka; Lungarella, Max

2017-01-01

Eccentric types of endurance exercise are an acknowledged alternative to conventional concentric types of exercise rehabilitation for the cardiac patient, because they reduce cardiorespiratory strain due to a lower metabolic cost of producing an equivalent mechanical output. The former contention has not been tested in a power- and work-matched situation of interval-type exercise under identical conditions because concentric and eccentric types of exercise pose specific demands on the exercise machinery, which are not fulfilled in current practice. Here we tested cardiovascular and muscular consequences of work-matched interval-type of leg exercise (target workload of 15 sets of 1-min bipedal cycles of knee extension and flexion at 30 rpm with 17% of maximal concentric power) on a soft robotic device in healthy subjects by concomitantly monitoring respiration, blood glucose and lactate, and power during exercise and recovery. We hypothesized that interval-type of eccentric exercise lowers strain on glucose-related aerobic metabolism compared to work-matched concentric exercise, and reduces cardiorespiratory strain to levels being acceptable for the cardiac patient. Eight physically active male subjects (24.0 years, 74.7 kg, 3.4 L O2 min−1), which power and endurance performance was extensively characterized, completed the study, finalizing 12 sets on average. Average performance was similar during concentric and eccentric exercise (p = 0.75) but lower than during constant load endurance exercise on a cycle ergometer at 75% of peak aerobic power output (126 vs. 188 Watt) that is recommended for improving endurance capacity. Peak oxygen uptake (−17%), peak ventilation (−23%), peak cardiac output (−16%), and blood lactate (−37%) during soft robotic exercise were lower during eccentric than concentric exercise. Glucose was 8% increased after eccentric exercise when peak RER was 12% lower than during concentric exercise. Muscle power and RFD were similarly reduced after eccentric and concentric exercise. The results highlight that the deployed interval-type of eccentric leg exercise reduces metabolic strain of the cardiovasculature and muscle compared to concentric exercise, to recommended levels for cardio-rehabilitation (i.e., 50–70% of peak heart rate). Increases in blood glucose concentration indicate that resistance to contraction-induced glucose uptake after the deployed eccentric protocol is unrelated to muscle fatigue. PMID:28912726

The effects of surface condition on abdominal muscle activity during single-legged hold exercise.

PubMed

Ha, Sung-min; Oh, Jae-seop; Jeon, In-cheol; Kwon, Oh-yun

2015-02-01

To treat low-back pain, various spinal stability exercises are commonly used to improve trunk muscle function and strength. Because human movement for normal daily activity occurs in multi-dimensions, the importance of exercise in multi-dimensions or on unstable surfaces has been emphasized. Recently, a motorized rotating platform (MRP) for facilitating multi-dimensions dynamic movement was introduced for clinical use. However, the abdominal muscle activity with this device has not been reported. The purpose of this study was to compare the abdominal muscle activity (rectus abdominis, external and internal oblique muscles) during an active single-leg-hold (SLH) exercise on a floor (stable surface), foam roll, and motorized rotating platform (MRP). Thirteen healthy male subjects participated in this study. Using electromyography, the abdominal muscle activity was measured while the subjects performed SLH exercises on floor (stable surface), foam roll, and MRP. There were significant differences in the abdominal muscle activities among conditions (P<.05), except for left EO (P>.05) (Fig. 2). After the Bonferroni correction, however, no significant differences among conditions remained, except for differences in both side IO muscle activity between the floor and foam roll conditions (padj<0.017). The findings suggest that performing the SLH exercises on a foam roll and MRP is more effective increased activities of both side of RA and IO, and Rt. EO compared to floor condition. However, there were no significant differences in abdominal muscles activity in the multiple comparison between conditions (mean difference were smaller than the standard deviation in the abdominal muscle activities) (padj>0.017), except for differences in both side IO muscle activity between the floor (stable surface) and foam roll (padj<0.017) (effect size: 0.79/0.62 (non-supporting/supporting leg) for foam-roll versus floor). Copyright © 2014 Elsevier Ltd. All rights reserved.

Vibration Platform Training in Women at Risk for Symptomatic Knee Osteoarthritis

PubMed Central

Segal, Neil A.; Glass, Natalie A.; Shakoor, Najia; Wallace, Robert

2013-01-01

Objective To determine whether a platform exercise program with vibration is more effective than the platform exercise alone for improving lower limb muscle strength and power in women age 45-60 with risk factors for knee osteoarthritis (OA). Design Randomized, controlled study Setting Academic center Participants 48 women age 45-60 years old with risk factors for knee OA (history of knee injury or surgery or BMI≥25kg/m2). Interventions Subjects were randomized to a twice weekly lower limb exercise program (quarter squat, posterolateral leg lifts, calf raises) on either a vertically vibrating (35Hz, 2mm), or a non-vibrating platform. Main Outcome Measurements The main outcome measures included change in isokinetic quadriceps strength, leg press power, and stair climb power by 12 weeks. Results 39 out of 48 enrolled participants completed the study (26 vibration and 13 control exercise). Nine participants discontinued the study after randomization mainly due to lack of time. There were no intergroup differences in age, BMI, or activity level. Isokinetic knee extensor strength did not significantly improve in either group. Leg press power improved by 92.0±69.7 W in the vibration group (p<.0001) and 58.2±96.2 W in the control group (p=0.0499), but did not differ between groups (p=0.2262). Stair climb power improved by 53.4±64.7 W in the vibration group (p=0.0004) and 55.7±83.3 W in the control group (p=0.0329), but did not differ between groups (p=0.9272). Conclusions Whole body vibration platforms have been marketed for increasing strength and power. In this group of asymptomatic middle-aged women with risk factors for knee OA, addition of vibration to a 12-week exercise program did not result in significantly greater improvement in lower limb strength or power than participation in the exercise program without vibration. PMID:22981005

Vibration platform training in women at risk for symptomatic knee osteoarthritis.

PubMed

Segal, Neil A; Glass, Natalie A; Shakoor, Najia; Wallace, Robert

2013-03-01

To determine whether a platform exercise program with vibration is more effective than platform exercise alone for improving lower limb muscle strength and power in women ages 45 to 60 with risk factors for knee osteoarthritis (OA). Randomized, controlled study. Academic center. A total of 48 women ages 45-60 years with risk factors for knee OA (a history of knee injury or surgery or body mass index ≥25 kg/m(2)). Subjects were randomly assigned to a twice-weekly lower limb exercise program (quarter squat, posterolateral leg lifts, calf raises, step-ups, and lunges) on either a vertically vibrating platform (35 Hz, 2 mm) or a nonvibrating platform. Change in isokinetic quadriceps strength, leg press power, and stair climb power by 12 weeks. A total of 39 of 48 enrolled participants completed the study (26 vibration and 13 control exercise). Nine participants discontinued the study after randomization mainly because of a lack of time. No intergroup differences in age, body mass index, or activity level existed. Isokinetic knee extensor strength did not significantly improve in either group. Leg press power improved by 92.0 ± 69.7 W in the vibration group (P < .0001) and 58.2 ± 96.2 W in the control group (P = .0499) but did not differ between groups (P = .2262). Stair climb power improved by 53.4 ± 64.7 W in the vibration group (P = .0004) and 55.7 ± 83.3 W in the control group (P = .0329) but did not differ between groups (P = .9272). Whole body vibration platforms have been marketed for increasing strength and power. In this group of asymptomatic middle-aged women with risk factors for knee OA, the addition of vibration to a 12-week exercise program did not result in significantly greater improvement in lower limb strength or power than did participation in the exercise program without vibration. Copyright © 2013 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Shin-splints: common exercise-related syndromes affecting the lower leg.

PubMed

Williamson, B L; Arthur, C H C

2014-01-01

Lower leg pain is a common complaint of athletically active individuals, often limiting physical activities. As such, the group of lower leg conditions related to athletic pursuits and physical exercise confer considerable operational implications for the military. Whilst acute injuries to the lower limb are commonly encountered and are clearly of significance, this article focuses instead on chronic conditions related to physical activity. These include insults to bone such as stress fractures and medial tibial stress syndrome, and those related to the soft tissues such as chronic exertional compartment syndrome. In this article we will examine the presentation and management of these conditions.

Leg muscle volume during 30-day 6-degree head-down bed rest with isotonic and isokinetic exercise training

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Lee, P. L.; Ellis, S.; Selzer, R. H.; Ortendahl, D. A.

1994-01-01

Magnetic resonance imaging (MRI) was used to compare the effect of two modes of lower-extremity exercise training on the mass (volume) of posterior leg group (PLG) muscles (soleus, flexor hallucis longus, tibialis posterior, lateral and medial gastrocnemius, and flexor digitorum longus) on 19 men (ages 32-42 years) subjected to intense dynamic-isotonic (ITE, cycle ergometer, number of subjects (N) = 7), isokinetic (IKE, torque egrometer, N = 7), and no exercise (NOE, N = 5) training for 60 min/day during head-down bed rest (HDBR). Total volume of the PLG muscles decreased (p less than 0.05) similarly: ITE = 4.3 +/- SE 1.6%, IKE = 7.7 +/- 1.6%, and NOE = 6.3 +/- 0.8%; combined volume (N = 19) loss was 6.1 +/- 0.9%. Ranges of volume changes were 2.6% to -9.0% (ITE), -2.1% to -14.9% (IKE), and -3.4% to -8/1% (NOE). Correlation coefficients (r) of muscle volume versus thickness measured with ultrasonography were: ITE r + 0.79 (p less than 0.05), IKE r = 0.27 (not significant (NS)), and NOE r = 0.63 (NS). Leg-muscle volume and thickness were highly correlated (r = 0.79) when plasma volume was maintained during HDBR with ITE. Thus, neither intensive lower extremity ITE nor IKE training influence the normal non-exercised posterior leg muscle atrophy during HDBR. The relationship of muscle volume and thickness may depend on the mode of exercise training associated with the maintenance of plasma volume.

Effects of daily activity recorded by pedometer on peak oxygen consumption (VO2peak), ventilatory threshold and leg extension power in 30- to 69-year-old Japanese without exercise habit.

PubMed

Zhang, Jian-Guo; Ohta, Toshiki; Ishikawa-Takata, Kazuko; Tabata, Izumi; Miyashita, Mitsumasa

2003-09-01

The relationships among walk steps, exercise habits and peak oxygen consumption (VO2peak), ventilatory threshold (VT) and leg extension power (LEP) were examined in 709 apparently healthy Japanese subjects (male 372, female 337) aged 30-69 years. Walk steps were evaluated using a pedometer. VO2peak and VT were assessed by a cycle ergometer test, while LEP was measured with an isokinetic leg extension system (Combi, Anaero Press 3500, Japan). Subjects who participated in exercise three times or more a week demonstrated significantly greater VO2peak and VT when compared with subjects without exercise habits. When a separate analysis was conducted on subjects who exercised fewer than three times per week, we found that the subgroup with the highest number of walk steps showed significantly greater VT in all male subjects and female subjects aged 30-49 years, but a significantly greater VO2peak only in females aged 30-49 years, when compared to the subgroup with the fewest walk steps. These results suggest that although some people exercise less than three times a week, if they are quite active in daily life, such activities might also confer benefits upon their fitness.

Gas exchange kinetics following concentric-eccentric isokinetic arm and leg exercise.

PubMed

Drescher, U; Mookerjee, S; Steegmanns, A; Knicker, A; Hoffmann, U

2017-06-01

To evaluate the effects of exercise velocity (60, 150, 240deg∙s -1 ) and muscle mass (arm vs leg) on changes in gas exchange and arterio-venous oxygen content difference (avDO 2 ) following high-intensity concentric-eccentric isokinetic exercise. Fourteen subjects (26.9±3.1years) performed a 3×20-repetition isokinetic exercise protocol. Recovery beat-to-beat cardiac output (CO) and breath-by-breath gas exchange were recorded to determine post-exercise half-time (t 1/2 ) for oxygen uptake (V˙O 2 pulm), carbon dioxide output (V˙CO 2 pulm), and ventilation (V˙ E ). Significant differences of the t 1/2 values were identified between 60 and 150deg∙s -1 . Significant differences in the t 1/2 values were observed between V˙O 2 pulm and V˙CO 2 pulm and between V˙CO 2 pulm and V˙ E . The time to attain the first avDO 2 -peak showed significant differences between arm and leg exercise. The present study illustrates, that V˙O 2 pulm kinetics are distorted due to non-linear CO dynamics. Therefore, it has to be taken into account, that V˙O 2 pulm may not be a valuable surrogate for muscular oxygen uptake kinetics in the recovery phases. Copyright © 2017 Elsevier B.V. All rights reserved.

Changes in passive tension of muscle in humans and animals after eccentric exercise

PubMed Central

Whitehead, N P; Weerakkody, N S; Gregory, J E; Morgan, D L; Proske, U

2001-01-01

This is a report of experiments on ankle extensor muscles of human subjects and a parallel series on the medial gastrocnemius of the anaesthetised cat, investigating the origin of the rise in passive tension after a period of eccentric exercise. Subjects exercised their triceps surae of one leg eccentrically by walking backwards on an inclined, forward-moving treadmill. Concentric exercise required walking forwards on a backwards-moving treadmill. For all subjects the other leg acted as a control. Immediately after both eccentric and concentric exercise there was a significant drop in peak active torque, but only after eccentric exercise was this accompanied by a shift in optimum angle for torque generation and a rise in passive torque. In the eccentrically exercised group some swelling and soreness developed but not until 24 h post-exercise. In the animal experiments the contracting muscle was stretched by 6 mm at 50 mm s−1 over a length range symmetrical about the optimum length for tension generation. Measurements of passive tension were made before and after the eccentric contractions, using small stretches to a range of muscle lengths, or with large stretches covering the full physiological range. After 150 eccentric contractions, passive tension was significantly elevated over most of the range of lengths. Measurements of work absorption during stretch-release cycles showed significant increases after the contractions. It is suggested that the rise in passive tension in both human and animal muscles after eccentric contractions is the result of development of injury contractures in damaged muscle fibres. PMID:11389215

The effect of an intensive exercise programme on leg function in chronic stroke patients: a pilot study with one-year follow-up.

PubMed

Stock, Roland; Mork, Paul Jarle

2009-09-01

To investigate the effect of two weeks of intensive exercise on leg function in chronic stroke patients and to evaluate the feasibility of an intensive exercise programme in a group setting. Pilot study with one-group pre-test post-test design with two pre-tests and one-year follow-up. Inpatient rehabilitation hospital. Twelve hemiparetic patients completed the intervention. Ten patients participated at one-year follow-up. Six hours of daily intensive exercise for two weeks with focus on weight-shifting towards the affected side and increased use of the affected extremity during functional activities. An insole with nubs in the shoe of the non-paretic limb was used to reinforce weight-shift toward the affected side. Timed Up and Go, Four Square Step Test, gait velocity, gait symmetry and muscle strength in knee and ankle muscles. Maximal gait velocity (P = 0.002) and performance time (seconds) on Timed Up and Go (mean, SD; 12.2, 3.8 vs. 9.4, 3.2) and Four Square Step Test improved from pre- to post-test (P = 0.005). Improvements remained significant at follow-up. Preferred gait velocity and gait symmetry remained unchanged. Knee extensor (P<50.009) and flexor (P<50.001) strength increased bilaterally from pre- to post-test but only knee flexor strength remained significant at follow-up. Ankle dorsi flexor (P = 0.02) and plantar flexor (P<0.001) strength increased on paretic side only (not tested at follow-up). Intensive exercise for lower extremity is feasible in a group setting and was effective in improving ambulatory function, maximal gait velocity and muscle strength in chronic stroke patients. Most improvements persisted at the one-year follow-up.

Central adaptations in aerobic circuit versus walking/jogging trained cardiac patients.

PubMed

Goodman, L S; McKenzie, D C; Nath, C R; Schamberger, W; Taunton, J E; Ammann, W C

1995-06-01

This study was done to determine (a) whether in coronary artery disease (CAD) left ventricular (LV) adaptations differed after 6 months of walking/jogging (legs-only, LO) versus aerobic circuit training (arms and legs, AL) versus a control group, and (b) whether a transfer of fitness to the untrained arms in the LO group was related to superior LV adaptations. Peak oxygen uptake for arm and leg ergometry and for cycle ergometry using radionuclide cardiac angiography were performed before and after training. Leg and arm VO2peak increased significantly by 13% in the AL group, and by 13% and 7%, respectively, for the LO group. LV function was greater after training for the LO versus the AL group. Improvements in systolic and diastolic function and a speculated hypervolemia explain these LV adaptations. In CAD patients, walking/jogging produces greater LV function improvements versus circuit training, possibly due to differences in the exercised muscle mass.

Motor imagery during action observation increases eccentric hamstring force: an acute non-physical intervention.

PubMed

Scott, Matthew; Taylor, Stephen; Chesterton, Paul; Vogt, Stefan; Eaves, Daniel Lloyd

2018-06-01

Rehabilitation professionals typically use motor imagery (MI) or action observation (AO) to increase physical strength for injury prevention and recovery. Here we compared hamstring force gains for MI during AO (AO + MI) against two pure MI training groups. Over a 3-week intervention physically fit adults imagined Nordic hamstring exercises in both legs and synchronized this with a demonstration of the same action (AO + MI), or they purely imagined this action (pure MI), or imagined upper-limb actions (pure MI-control). Eccentric hamstring strength gains were assessed using ANOVAs, and magnitude-based inference (MBI) analyses determined the likelihood of clinical/practical benefits for the interventions. Hamstring strength only increased significantly following AO + MI training. This effect was lateralized to the right leg, potentially reflecting a left-hemispheric dominance in motor simulation. MBIs: The right leg within-group treatment effect size for AO + MI was moderate and likely beneficial (d = 0.36), and only small and possibly beneficial for pure MI (0.23). Relative to pure MI-control, effects were possibly beneficial and moderate for AO + MI (0.72), although small for pure MI (0.39). Since hamstring strength predicts injury prevalence, our findings point to the advantage of combined AO + MI interventions, over and above pure MI, for injury prevention and rehabilitation. Implications for rehabilitation While hamstring strains are the most common injury across the many sports involving sprinting and jumping, Nordic hamstring exercises are among the most effective methods for building eccentric hamstring strength, for injury prevention and rehabilitation. In the acute injury phase it is crucial not to overload damaged soft tissues, and so non-physical rehabilitation techniques are well suited to this phase. Rehabilitation professionals typically use either motor imagery or action observation techniques to safely improve physical strength, but our study shows that motor imagery during observation of Nordic hamstring exercises offers a safe, affordable and more effective way to facilitate eccentric hamstring strength gains, compared with pure motor imagery. Despite using bilateral imagery and observation training conditions in the present study, strength gains were restricted to the right leg, potentially due to a left hemispheric dominance in motor simulation.

The 12-week progressive quadriceps resistance training improves muscle strength, exercise capacity and quality of life in patients with stable chronic heart failure.

PubMed

Jankowska, Ewa A; Wegrzynowska, Kinga; Superlak, Malgorzata; Nowakowska, Katarzyna; Lazorczyk, Malgorzata; Biel, Bartosz; Kustrzycka-Kratochwil, Dorota; Piotrowska, Katarzyna; Banasiak, Waldemar; Wozniewski, Marek; Ponikowski, Piotr

2008-10-30

Abnormalities in the skeletal musculature underlie exercise intolerance in chronic heart failure (CHF). We investigated, whether in CHF selective resistance training without accompanying aerobic regime favourably affects muscle strength, muscle mass and improves exercise capacity. Ten patients with stable ischaemic CHF in NYHA class III (9 men, age: 70+/-6 years [mean+/-SD], left ventricular ejection fraction: 30+/-5%, peak oxygen consumption [peak VO(2)]: 12.4+/-3.0 mL/min/kg) underwent the rehabilitation programme which consisted of a 12-week training phase (progressive resistance exercises restricted to the quadriceps muscles) followed by a 12-week detraining phase. All subjects completed a training phase of the programme with no adverse events. Resistance training markedly increased quadriceps strength (right leg: 260+/-34 vs. 352+/-28 N, left leg: 264+/-38 vs. 342+/-30 N, both p<0.01 - all comparisons: baseline vs. after training), but did not affect lean tissue mass of lower extremities (both p>0.2). It was accompanied by an improvement in clinical status (all NYHA III vs. all NYHA II, p<0.01), quality of life (Minnesota questionnaire: 44+/-15 vs. 33+/-18 points, p<0.05), exercise capacity assessed using a distance during 6-minute walk test (6MWT: 362+/-83 vs. 455+/-71 m, p<0.01), but not peak VO(2) (p>0.2). Plasma NT-proBNP remained unchanged during the training. At the end of detraining phase, only a partial improvement in quadriceps strength (p<0.05), a 6MWT distance (p<0.05) and NYHA class (p=0.07 vs. baseline) persisted. Applied resistance quadriceps training is safe in patients with CHF. It increases muscle strength, improves clinical status, exercise capacity, and quality of life.

Mechanical design and driving mechanism of an isokinetic functional electrical stimulation-based leg stepping trainer.

PubMed

Hamzaid, N A; Fornusek, C; Ruys, A; Davis, G M

2007-12-01

The mechanical design of a constant velocity (isokinetic) leg stepping trainer driven by functional electrical stimulation-evoked muscle contractions was the focus of this paper. The system was conceived for training the leg muscles of neurologically-impaired patients. A commercially available slider crank mechanism for elliptical stepping exercise was adapted to a motorized isokinetic driving mechanism. The exercise system permits constant-velocity pedalling at cadences of 1-60 rev x min(-1). The variable-velocity feature allows low pedalling forces for individuals with very weak leg muscles, yet provides resistance to higher pedalling effort in stronger patients. In the future, the system will be integrated with a computer-controlled neuromuscular stimulator and a feedback control unit to monitor training responses of spinal cord-injured, stroke and head injury patients.

Muscle Activity in Single- vs. Double-Leg Squats.

PubMed

DeFOREST, Bradley A; Cantrell, Gregory S; Schilling, Brian K

Muscular activity, vertical displacement and ground reaction forces of back squats (BS), rear-leg elevated split squats (RLESS) and split squats (SS) were examined. Nine resistance-trained men reported for two sessions. The first session consisted of the consent process, practice, and BS 1-repetition maximum testing. In the second session, participants performed the three exercises while EMG, displacment and ground reaction force data (one leg on plate) were collected. EMG data were collected from the gluteus maximus (GMX), biceps femoris (BF), semitendinosus (ST), rectus femoris (RF), vastus lateralis (VL), vastus medialis (VM), tibialis anterior (TA), and medial gastrocnemius (MGas) of the left leg (non-dominant, front leg for unilateral squats). Load for BS was 85% one repetition maximum, and RLESS and SS were performed at 50% of BS load. Repeated measures ANOVA was used to compare all variables for the three exercises, with Bonferroni adjustments for post hoc multiple comparisons, in addition to calculation of standardized mean differences (ES). Muscle activity was similar between exercises except for biceps femoris, which was significantly higher during RLESS than SS during both concentric and eccentric phases (ES = 2.11; p=0.012 and ES= 2.19; p=0.008), and significantly higher during BS than the SS during the concentric phase (ES = 1.78; p=0.029). Vertical displacement was similar between all exercises. Peak vertical force was similar between BS and RLESS and significantly greater during RLESS than SS (ES = 3.03; p=0.001). These findings may be helpful in designing resistance training programs by using RLESS if greater biceps femoris activity is desired.

Muscle Activity in Single- vs. Double-Leg Squats

PubMed Central

DeFOREST, BRADLEY A.; CANTRELL, GREGORY S.; SCHILLING, BRIAN K.

2014-01-01

Muscular activity, vertical displacement and ground reaction forces of back squats (BS), rear-leg elevated split squats (RLESS) and split squats (SS) were examined. Nine resistance-trained men reported for two sessions. The first session consisted of the consent process, practice, and BS 1-repetition maximum testing. In the second session, participants performed the three exercises while EMG, displacment and ground reaction force data (one leg on plate) were collected. EMG data were collected from the gluteus maximus (GMX), biceps femoris (BF), semitendinosus (ST), rectus femoris (RF), vastus lateralis (VL), vastus medialis (VM), tibialis anterior (TA), and medial gastrocnemius (MGas) of the left leg (non-dominant, front leg for unilateral squats). Load for BS was 85% one repetition maximum, and RLESS and SS were performed at 50% of BS load. Repeated measures ANOVA was used to compare all variables for the three exercises, with Bonferroni adjustments for post hoc multiple comparisons, in addition to calculation of standardized mean differences (ES). Muscle activity was similar between exercises except for biceps femoris, which was significantly higher during RLESS than SS during both concentric and eccentric phases (ES = 2.11; p=0.012 and ES= 2.19; p=0.008), and significantly higher during BS than the SS during the concentric phase (ES = 1.78; p=0.029). Vertical displacement was similar between all exercises. Peak vertical force was similar between BS and RLESS and significantly greater during RLESS than SS (ES = 3.03; p=0.001). These findings may be helpful in designing resistance training programs by using RLESS if greater biceps femoris activity is desired. PMID:27182408

Acute L-arginine alpha ketoglutarate supplementation fails to improve muscular performance in resistance trained and untrained men.

PubMed

Wax, Benjamin; Kavazis, Andreas N; Webb, Heather E; Brown, Stanley P

2012-04-17

Dietary supplements containing L-arginine are marketed to improve exercise performance, but the efficacy of such supplements is not clear. Therefore, this study examined the efficacy of acute ingestion of L-arginine alpha-ketoglutarate (AAKG) muscular strength and endurance in resistance trained and untrained men. Eight resistance trained and eight untrained healthy males ingested either 3000mg of AAKG or a placebo 45 minutes prior to a resistance exercise protocol in a randomized, double-blind crossover design. One-repetition maximum (1RM) on the standard barbell bench press and leg press were obtained. Upon determination of 1RM, subjects completed repetitions to failure at 60% 1RM on both the standard barbell bench press and leg press. Heart rate was measured pre and post exercise. One week later, subjects ingested the other supplement and performed the identical resistance exercise protocol. Our data showed statistical significant differences (p<0.05) between resistance trained and untrained males for both 1RM and total load volume (TLV; multiply 60% of 1RM times the number of repetitions to failure) for the upper body. However, 1RM and TLV were not statistically different (p>0.05) between supplementation conditions for either resistance trained or untrained men in the bench press or leg press exercises. Heart rate was similar at the end of the upper and lower body bouts of resistance exercise with AAKG vs. placebo. The results from our study indicate that acute AAKG supplementation provides no ergogenic benefit on 1RM or TLV as measured by the standard barbell bench press and leg press, regardless of the subjects training status.

Human muscle net K(+) release during exercise is unaffected by elevated anaerobic metabolism, but reduced after prolonged acclimatization to 4,100 m.

PubMed

Nordsborg, Nikolai B; Calbet, José A L; Sander, Mikael; van Hall, Gerrit; Juel, Carsten; Saltin, Bengt; Lundby, Carsten

2010-07-01

It was investigated whether skeletal muscle K(+) release is linked to the degree of anaerobic energy production. Six subjects performed an incremental bicycle exercise test in normoxic and hypoxic conditions prior to and after 2 and 8 wk of acclimatization to 4,100 m. The highest workload completed by all subjects in all trials was 260 W. With acute hypoxic exposure prior to acclimatization, venous plasma [K(+)] was lower (P < 0.05) in normoxia (4.9 +/- 0.1 mM) than hypoxia (5.2 +/- 0.2 mM) at 260 W, but similar at exhaustion, which occurred at 400 +/- 9 W and 307 +/- 7 W (P < 0.05), respectively. At the same absolute exercise intensity, leg net K(+) release was unaffected by hypoxic exposure independent of acclimatization. After 8 wk of acclimatization, no difference existed in venous plasma [K(+)] between the normoxic and hypoxic trial, either at submaximal intensities or at exhaustion (360 +/- 14 W vs. 313 +/- 8 W; P < 0.05). At the same absolute exercise intensity, leg net K(+) release was less (P < 0.001) than prior to acclimatization and reached negative values in both hypoxic and normoxic conditions after acclimatization. Moreover, the reduction in plasma volume during exercise relative to rest was less (P < 0.01) in normoxic than hypoxic conditions, irrespective of the degree of acclimatization (at 260 W prior to acclimatization: -4.9 +/- 0.8% in normoxia and -10.0 +/- 0.4% in hypoxia). It is concluded that leg net K(+) release is unrelated to anaerobic energy production and that acclimatization reduces leg net K(+) release during exercise.

The exercise and environmental physiology of extravehicular activity

NASA Technical Reports Server (NTRS)

Cowell, Stephenie A.; Stocks, Jodie M.; Evans, David G.; Simonson, Shawn R.; Greenleaf, John E.

2002-01-01

Extravehicular activity (EVA), i.e., exercise performed under unique environmental conditions, is indispensable for supporting daily living in weightlessness and for further space exploration. From 1965-1996 an average of 20 h x yr(-1) were spent performing EVA. International Space Station (ISS) assembly will require 135 h x yr(-1) of EVA, and 138 h x yr(-1) is planned for post-construction maintenance. The extravehicular mobility unit (EMU), used to protect astronauts during EVA, has a decreased pressure of 4.3 psi that could increase astronauts' risk of decompression sickness (DCS). Exercise in and repeated exposure to this hypobaria may increase the incidence of DCS, although weightlessness may attenuate this risk. Exercise thermoregulation within the EMU is poorly understood; the liquid cooling garment (LCG), worn next to the skin and designed to handle thermal stress, is manually controlled. Astronauts may become dehydrated (by up to 2.6% of body weight) during a 5-h EVA, further exacerbating the thermoregulatory challenge. The EVA is performed mainly with upper body muscles; but astronauts usually exercise at only 26-32% of their upper body maximal oxygen uptake (VO2max). For a given ground-based work task in air (as opposed to water), the submaximal VO2 is greater while VO2max and metabolic efficiency are lower during ground-based arm exercise as compared with leg exercise, and cardiovascular responses to exercise and training are also different for arms and legs. Preflight testing and training, whether conducted in air or water, must account for these differences if ground-based data are extrapolated for flight requirements. Astronauts experience deconditioning during microgravity resulting in a 10-20% loss in arm strength, a 20-30% loss in thigh strength, and decreased lower-body aerobic exercise capacity. Data from ground-based simulations of weightlessness such as bed rest induce a 6-8% decrease in upper-body strength, a 10-16% loss in thigh extensor strength, and a 15-20% decrease in lower-body aerobic exercise capacity. Changes in EVA support systems and training based on a greater understanding of the physiological aspects of exercise in the EVA environment will help to insure the health, safety, and efficiency of working astronauts.

The exercise and environmental physiology of extravehicular activity.

PubMed

Cowell, Stephenie A; Stocks, Jodie M; Evans, David G; Simonson, Shawn R; Greenleaf, John E

2002-01-01

Extravehicular activity (EVA), i.e., exercise performed under unique environmental conditions, is indispensable for supporting daily living in weightlessness and for further space exploration. From 1965-1996 an average of 20 h x yr(-1) were spent performing EVA. International Space Station (ISS) assembly will require 135 h x yr(-1) of EVA, and 138 h x yr(-1) is planned for post-construction maintenance. The extravehicular mobility unit (EMU), used to protect astronauts during EVA, has a decreased pressure of 4.3 psi that could increase astronauts' risk of decompression sickness (DCS). Exercise in and repeated exposure to this hypobaria may increase the incidence of DCS, although weightlessness may attenuate this risk. Exercise thermoregulation within the EMU is poorly understood; the liquid cooling garment (LCG), worn next to the skin and designed to handle thermal stress, is manually controlled. Astronauts may become dehydrated (by up to 2.6% of body weight) during a 5-h EVA, further exacerbating the thermoregulatory challenge. The EVA is performed mainly with upper body muscles; but astronauts usually exercise at only 26-32% of their upper body maximal oxygen uptake (VO2max). For a given ground-based work task in air (as opposed to water), the submaximal VO2 is greater while VO2max and metabolic efficiency are lower during ground-based arm exercise as compared with leg exercise, and cardiovascular responses to exercise and training are also different for arms and legs. Preflight testing and training, whether conducted in air or water, must account for these differences if ground-based data are extrapolated for flight requirements. Astronauts experience deconditioning during microgravity resulting in a 10-20% loss in arm strength, a 20-30% loss in thigh strength, and decreased lower-body aerobic exercise capacity. Data from ground-based simulations of weightlessness such as bed rest induce a 6-8% decrease in upper-body strength, a 10-16% loss in thigh extensor strength, and a 15-20% decrease in lower-body aerobic exercise capacity. Changes in EVA support systems and training based on a greater understanding of the physiological aspects of exercise in the EVA environment will help to insure the health, safety, and efficiency of working astronauts.

One-year unsupervised individualized exercise training intervention enhances cardiorespiratory fitness but not muscle deoxygenation or glycemic control in adults with type 1 diabetes.

PubMed

Rissanen, Antti-Pekka E; Tikkanen, Heikki O; Koponen, Anne S; Aho, Jyrki M; Peltonen, Juha E

2018-04-01

Adaptations to long-term exercise training in type 1 diabetes are sparsely studied. We examined the effects of a 1-year individualized training intervention on cardiorespiratory fitness, exercise-induced active muscle deoxygenation, and glycemic control in adults with and without type 1 diabetes. Eight men with type 1 diabetes (T1D) and 8 healthy men (CON) matched for age, anthropometry, and peak pulmonary O 2 uptake, completed a 1-year individualized training intervention in an unsupervised real-world setting. Before and after the intervention, the subjects performed a maximal incremental cycling test, during which alveolar gas exchange (volume turbine and mass spectrometry) and relative concentration changes in active leg muscle deoxygenated (Δ[HHb]) and total (Δ[tHb]) hemoglobin (near-infrared spectroscopy) were monitored. Peak O 2 pulse, reflecting peak stroke volume, was calculated (peak pulmonary O 2 uptake/peak heart rate). Glycemic control (glycosylated hemoglobin A 1c (HbA 1c )) was evaluated. Both T1D and CON averagely performed 1 resistance-training and 3-4 endurance-training sessions per week (∼1 h/session at ∼moderate intensity). Training increased peak pulmonary O 2 uptake in T1D (p = 0.004) and CON (p = 0.045) (group × time p = 0.677). Peak O 2 pulse also rose in T1D (p = 0.032) and CON (p = 0.018) (group × time p = 0.880). Training increased leg Δ[HHb] at peak exercise in CON (p = 0.039) but not in T1D (group × time p = 0.052), while no changes in leg Δ[tHb] at any work rate were observed in either group (p > 0.05). HbA 1c retained unchanged in T1D (from 58 ± 10 to 59 ± 11 mmol/mol, p = 0.609). In conclusion, 1-year adherence to exercise training enhanced cardiorespiratory fitness similarly in T1D and CON but had no effect on active muscle deoxygenation or glycemic control in T1D.

Exercise Is Key to Healthy Aging

MedlinePlus

... on two or more days a week that work all major muscle groups (legs, hips, back, abdomen, chest, shoulders, and arms). You can do balance and flexibility exercises any time. Is it safe to exercise? Exercise is safe for almost everyone. Studies show that people with arthritis, high blood pressure, ...

IGF-I Polymorphism is Associated with Lean Mass, Exercise Economy and Performance Among Premenopausal Women

PubMed Central

López-Alarcón, Mardya; Hunter, Gary R.; Gower, Barba A.; Fernández, José R.

2007-01-01

Background We undertook this study to investigate the association of a genetic polymorphism of the insulin-like growth factor, IGF-I189, on body composition, exercise performance and exercise economy, after controlling for the independent effect of race as assessed by African genetic admixture (AFADM). Methods A total of 114 premenopausal sedentary women were genotyped for IGF-I189, obtaining measures of fat mass, lean body mass, VO2 during cycling and stairclimbing, time on treadmill and leg strength. A quantitative value for AFADM was derived from genotypic information of approximately 40 ancestry informative markers and used as covariate in statistical models. Results After adjusting for AFADM, IGF-I189 was negatively associated with lean body mass (p = 0.029) and lean leg mass (p = 0.050). Leg strength was not associated with the presence/absence of IGF-I189 (p = 0.380), but carriers of the allele demonstrated a longer time on the treadmill (p = 0.015) after adjusting for AFADM. There was also a negative relationship between oxygen uptake during cycling and presence of the IGF-I189 independent of AFADM (p = 0.010). Conclusion Independent of AFADM, individuals with IGF-I189 are more likely to have low leg lean mass and to perform better in activities requiring exercise economy and endurance performance. PMID:17174724

Balance exercise in patients with chronic sensory ataxic neuropathy: a pilot study.

PubMed

Riva, Nilo; Faccendini, Simone; Lopez, Ignazio D; Fratelli, Annamaria; Velardo, Daniele; Quattrini, Angelo; Gatti, Roberto; Comi, Giancarlo; Comola, Mauro; Fazio, Raffaella

2014-06-01

Although exercise therapy is considered part of the treatment of neuropathic patients, and somatosensory input is essential for motor learning, performance and neural plasticity, rehabilitation of patients with sensory ataxia has received little attention so far. The aim of this prospective pilot study was to explore the short- and medium-term efficacy of a 3-week intensive balance and treadmill exercise program in chronic ataxic neuropathy patients; 20 consecutive patients with leg overall disability sum score (ODSS-leg) ≥2, absent/mild motor signs, clinical and therapeutic stability ≥4 months were enrolled. Evaluations were done at baseline, at the end of treatment and at 3- and 6-month follow-up. Outcome measurements included: ODSS-leg, Berg balance scale, 6-min walk distance, and the functional independence measure (FIM) scale. The short-form-36 health status scale (SF-36) was used to measure health-related quality of life (HRQoL). ODSS-leg improved significantly compared with baseline, 3 weeks, 3 months (primary outcome), and 6 months follow-up. A significant improvement in all functional secondary outcome measurements and in some SF-36 subscales was also observed. This pilot study suggests that balance exercise is safe and well tolerated and might be effective in ameliorating disability and HRQoL in patients with chronic peripheral sensory ataxia. © 2014 Peripheral Nerve Society.

Strength tests for elite rowers: low- or high-repetition?

PubMed

Lawton, Trent W; Cronin, John B; McGuigan, Michael R

2014-01-01

The purpose of this project was to evaluate the utility of low- and high-repetition maximum (RM) strength tests used to assess rowers. Twenty elite heavyweight males (age 23.7 ± 4.0 years) performed four tests (5 RM, 30 RM, 60 RM and 120 RM) using leg press and seated arm pulling exercise on a dynamometer. Each test was repeated on two further occasions; 3 and 7 days from the initial trial. Per cent typical error (within-participant variation) and intraclass correlation coefficients (ICCs) were calculated using log-transformed repeated-measures data. High-repetition tests (30 RM, 60 RM and 120 RM), involving seated arm pulling exercise are not recommended to be included in an assessment battery, as they had unsatisfactory measurement precision (per cent typical error > 5% or ICC < 0.9). Conversely, low-repetition tests (5 RM) involving leg press and seated arm pulling exercises could be used to assess elite rowers (per cent typical error ≤ 5% and ICC ≥ 0.9); however, only 5 RM leg pressing met criteria (per cent typical error = 2.7%, ICC = 0.98) for research involving small samples (n = 20). In summary, low-repetition 5 RM strength testing offers greater utility as assessments of rowers, as they can be used to measure upper- and lower-body strength; however, only the leg press exercise is recommended for research involving small squads of elite rowers.

Are Changes in Leg Power Responsible for Clinically Meaningful Improvements in Mobility Among Older Adults?

PubMed Central

Bean, Jonathan F.; Kiely, Dan K.; LaRose, Sharon; Goldstein, Richard; Frontera, Walter R.; Leveille, Suzanne G.

2010-01-01

Objectives Mobility as measured by the Short Physical Performance Battery (SPPB) or habitual Gait Speed (GS) is predictive of mortality and disability among older adults. Clinically meaningful changes of these measures have been identified. Among physiologic attributes commonly targeted in rehabilitation, we sought to identify those attributes in which changes led to clinically meaningful differences (CMD) in the mobility outcomes. Participants Community-dwelling, mobility-limited older adults (n=116) participating in a 16-week randomized controlled trial (RCT) of two modes of exercise Setting Outpatient rehabilitation centers Design Secondary analysis of data collected for a RCT of exercise using binary outcomes defined by recording a large CMD (SPPB=1 unit; GS=.1m/s). Iterative models were performed to evaluate possible confounding between physiologic variables and relevant covariates. Measures Physiologic measures included leg power, leg strength, balance as measured by the Performance Oriented Mobility Assessment (POMA), rate pressure product (RPP) at the maximal stage of an exercise tolerance test. Outcomes included GS and SPPB. Leg power and leg strength were measured using computerized pneumatic strength training equipment and recorded in Watts and Newtons respectively. Results Participants were 68% female, had a mean age of 75.2 years, with a mean of 5.5 chronic conditions and a baseline mean SPPB score of 8.7. After controlling for age, site, group assignment, and baseline outcome values, leg power was the only attribute in which changes were significantly associated with a large CMD in SPPB (OR 1.48, 95% CI 1.09, 2.02) and GS (OR1.31, 95% CI 1.01, 1.70). Conclusion Improvements in leg power, independent of strength, appear to make an important contribution towards clinically meaningful improvements in both SPPB and GS. PMID:21143443

Are changes in leg power responsible for clinically meaningful improvements in mobility in older adults?

PubMed

Bean, Jonathan F; Kiely, Dan K; LaRose, Sharon; Goldstein, Richard; Frontera, Walter R; Leveille, Suzanne G

2010-12-01

From among physiological attributes commonly targeted in rehabilitation, to identify those in which changes led to clinically meaningful differences (CMDs) in mobility outcomes. Secondary analysis of data collected for a randomized controlled trial of exercise using binary outcomes defined by recording a large CMD (Short Physical Performance Battery (SPPB)=1 unit; gait speed (GS)=0.1 m/s). Iterative models were performed to evaluate possible confounding between physiological variables and relevant covariates. Outpatient rehabilitation centers. Community-dwelling mobility-limited older adults (n=116) participating in a 16-week randomized controlled trial of two modes of exercise. Physiological measures included leg power, leg strength, balance as measured according to the Performance-Oriented Mobility Assessment (POMA), and rate pressure product at the maximal stage of an exercise tolerance test. Outcomes included GS and SPPB. Leg power and leg strength were measured using computerized pneumatic strength training equipment and recorded in Watts and Newtons, respectively. Participants were 68% female, had a mean age of 75.2, a mean of 5.5 chronic conditions, and a baseline mean SPPB score of 8.7. After controlling for age, site, group assignment, and baseline outcome values, leg power was the only attribute in which changes were significantly associated with a large CMD in SPPB (odds ratio (OR)=1.48, 95% confidence interval (CI)=1.09-2.02) and GS (OR=1.31, 95% CI=1.01-1.70). Improvements in leg power, independent of strength, appear to make an important contribution to clinically meaningful improvements in SPPB and GS. © 2010, Copyright the Authors. Journal compilation © 2010, The American Geriatrics Society.

Pulmonary rehabilitation improves cardiovascular response to exercise in COPD.

PubMed

Ramponi, Sara; Tzani, Panagiota; Aiello, Marina; Marangio, Emilio; Clini, Enrico; Chetta, Alfredo

2013-01-01

Pulmonary rehabilitation (PR) has emerged as a recommended standard of care in symptomatic COPD. We now studied whether PR may affect cardiovascular response to exercise in these patients. Twenty-seven patients (9 females aged 69 ± 8 years) with moderate-to-severe airflow obstruction admitted to a 9-week PR course performed a pre-to-post evaluation of lung function test and symptom-limited cardiopulmonary exercise test (CPET). Oxygen uptake (VO2), tidal volume (V(T)), dyspnea and leg fatigue scores were measured during CPET. Cardiovas-cular response was assessed by means of oxygen pulse (O2Pulse), the oxygen uptake efficiency slope and heart rate recovery at the 1st min. A significant increase in peak VO2 and in all cardiovascular parameters (p < 0.05) was found following PR when compared to baseline. Leg fatigue (p < 0.05), but not dyspnea, was significantly reduced after PR. When assessed at metabolic and ventilatory iso levels [% VCO2max and % minute ventilation (VEmax)], O2Pulse and V(T) were significantly higher (p < 0.05) at submaximal exercise (75 and 50% of VCO2max and VEmax) after PR when compared to baseline. V(T) percent changes at 75% VCO2max and 75% VEmax after PR significantly correlated with corresponding changes in O2Pulse (p < 0.01). In COPD patients, a PR training program improved the cardiovascular response during exercise at submaximal exercise independent of the external workload. This change was associated with an enhanced ventilatory function during exercise. Copyright © 2013 S. Karger AG, Basel.

An approach to counteracting long-term microgravity-induced muscle atrophy

NASA Technical Reports Server (NTRS)

Tesch, P. A.; Buchanan, P.; Dudley, G. A.

1990-01-01

To find means of alleviating muscle atrophy induced by long-term microgravity, the effects of a 19-week-long heavy-resistance training regime (using either concentric muscle actions only or concentric and eccentric muscle actions) on the strengths of the exercised knee extensor muscle group were investigated in two groups of male human subjects performing two types of training exercises: supine leg press or/and seated knee extension. Results show that a training program in which both the concentric and the eccentric muscle action was performed led to substantially greater increases in maximal muscle strength than when only concentric exercises were performed.

Training with the International Space Station interim resistive exercise device

NASA Technical Reports Server (NTRS)

Schneider, Suzanne M.; Amonette, William E.; Blazine, Kristi; Bentley, Jason; Lee, Stuart M C.; Loehr, James A.; Moore, Alan D Jr; Rapley, Michael; Mulder, Edwin R.; Smith, Scott M.

2003-01-01

A unique, interim elastomer-based resistive exercise device (iRED) is being used on the International Space Station. PURPOSE: This study characterized iRED training responses in a 1-g environment by: 1) determining whether 16 wk of high-intensity training with iRED produces increases in muscle strength and volume and bone mineral density (BMD), 2) comparing training responses with iRED to free weights, and 3) comparing iRED training responses at two training volumes. METHODS: Twenty-eight untrained men were assigned to four groups of seven subjects each: a no exercise control group (CON), an iRED group who trained with three sets/exercise (iRED3), a free-weight group (FW) who trained with three sets/exercise, and an iRED group who trained with six sets/exercise (iRED6). Training exercises included squat (SQ), heel raise (HR), and dead lift (DL) exercises, 3 d.wk(-1) for 16 wk. RESULTS: For CON, no changes occurred pre- to posttraining. For iRED3, increases (P< or =0.05) in one-repetition maximum (1-RM) strength (SQ 21 +/- 4%, HR 17 +/- 4%, DL 29 +/- 5%), leg lean mass (3.1 +/- 0.5%) by dual energy x-ray absorptiometry (DXA), and thigh (4.5 +/- 0.9%) and calf (5.9 +/- 0.7%) muscle volume (by magnetic resonance imaging) occurred after training with no changes in BMD (DXA). For FW, increases in 1-RM strength (SQ 22 +/- 5%, HR 24 +/- 3%, DL 41 +/- 7%), whole body (3.0 +/- 1.1%) and leg lean mass (5.4 +/- 1.2%), thigh (9.2 +/- 1.3%) and calf (4.2 +/- 1.0%) muscle volumes, and lumbar BMD (4.2 +/- 0.7%) occurred after training. For iRED6, all responses were similar to iRED3. CONCLUSION: High-intensity training with the iRED produced muscle responses similar to FW but was not effective in stimulating bone. Bed rest and spaceflight studies are needed to evaluate the effectiveness of the iRED to prevent microgravity deconditioning.

Rating of Perceived Exertion During Circuit Weight Training: A Concurrent Validation Study.

PubMed

Aniceto, Rodrigo R; Ritti-Dias, Raphael M; Dos Prazeres, Thaliane M P; Farah, Breno Q; de Lima, Fábio F M; do Prado, Wagner L

2015-12-01

The aim of this study was to determine whether rating of perceived exertion (RPE) is a valid method to control the effort during the circuit weight training (CWT) in trained men. Ten men (21.3 ± 3.3 years) with previous experience in resistance training (13.1 ± 6.3 months) performed 3 sessions: 1 orientation session and 2 experimental sessions. The subjects were randomly counterbalanced to 2 experimental sessions: CWT or multiple-set resistance training (control). In both sessions, 8 exercises (bench press, leg press 45°, seated row, leg curl, triceps pulley, leg extension, biceps curl, and adductor chair) were performed with the same work: 60% of 1 repetition maximum, 24 stations (3 circuits) or 24 sets (3 sets/exercise), 10 repetitions, 1 second in the concentric and eccentric phases, and rest intervals between sets and exercise of 60 seconds. Active muscle RPEs were measured after each 3 station/sets using the OMNI-Resistance Exercise Scale (OMNI-RES). In this same time, blood lactate was collected. Compared with baseline, both levels of blood lactate and RPE increased during whole workout in both sessions, the RPE at third, 23rd, and 27th minute and the blood lactate at third, seventh, 11th, 15th, 27th, and 31st minute were higher in multiple set compared with CWT. Positive correlation between blood lactate and RPE was observed in both experimental sessions. The results indicated that the RPE is a valid method to control the effort during the CWT in trained men and can be used to manipulate the intensity without the need to perform invasive assessments.

Associations of exercise-induced hormone profiles and gains in strength and hypertrophy in a large cohort after weight training.

PubMed

West, Daniel W D; Phillips, Stuart M

2012-07-01

The purpose of this study was to investigate associations between acute exercise-induced hormone responses and adaptations to high intensity resistance training in a large cohort (n = 56) of young men. Acute post-exercise serum growth hormone (GH), free testosterone (fT), insulin-like growth factor (IGF-1) and cortisol responses were determined following an acute intense leg resistance exercise routine at the midpoint of a 12-week resistance exercise training study. Acute hormonal responses were correlated with gains in lean body mass (LBM), muscle fibre cross-sectional area (CSA) and leg press strength. There were no significant correlations between the exercise-induced elevations (area under the curve-AUC) of GH, fT and IGF-1 and gains in LBM or leg press strength. Significant correlations were found for cortisol, usually assumed to be a hormone indicative of catabolic drive, AUC with change in LBM (r = 0.29, P < 0.05) and type II fibre CSA (r = 0.35, P < 0.01) as well as GH AUC and gain in fibre area (type I: r = 0.36, P = 0.006; type II: r = 0.28, P = 0.04, but not lean mass). No correlations with strength were observed. We report that the acute exercise-induced systemic hormonal responses of cortisol and GH are weakly correlated with resistance training-induced changes in fibre CSA and LBM (cortisol only), but not with changes in strength.

Movement velocity as a measure of exercise intensity in three lower limb exercises.

PubMed

Conceição, Filipe; Fernandes, Juvenal; Lewis, Martin; Gonzaléz-Badillo, Juan José; Jimenéz-Reyes, Pedro

2016-01-01

The purpose of this study was to investigate the relationship between movement velocity and relative load in three lower limbs exercises commonly used to develop strength: leg press, full squat and half squat. The percentage of one repetition maximum (%1RM) has typically been used as the main parameter to control resistance training; however, more recent research has proposed movement velocity as an alternative. Fifteen participants performed a load progression with a range of loads until they reached their 1RM. Maximum instantaneous velocity (Vmax) and mean propulsive velocity (MPV) of the knee extension phase of each exercise were assessed. For all exercises, a strong relationship between Vmax and the %1RM was found: leg press (r(2)adj = 0.96; 95% CI for slope is [-0.0244, -0.0258], P < 0.0001), full squat (r(2)adj = 0.94; 95% CI for slope is [-0.0144, -0.0139], P < 0.0001) and half squat (r(2)adj = 0.97; 95% CI for slope is [-0.0135, -0.00143], P < 0.0001); for MPV, leg press (r(2)adj = 0.96; 95% CI for slope is [-0.0169, -0.0175], P < 0.0001, full squat (r(2)adj = 0.95; 95% CI for slope is [-0.0136, -0.0128], P < 0.0001) and half squat (r(2)adj = 0.96; 95% CI for slope is [-0.0116, 0.0124], P < 0.0001). The 1RM was attained with a MPV and Vmax of 0.21 ± 0.06 m s(-1) and 0.63 ± 0.15 m s(-1), 0.29 ± 0.05 m s(-1) and 0.89 ± 0.17 m s(-1), 0.33 ± 0.05 m s(-1) and 0.95 ± 0.13 m s(-1) for leg press, full squat and half squat, respectively. Results indicate that it is possible to determine an exercise-specific %1RM by measuring movement velocity for that exercise.

Physiological Correlates of Endurance Time Variability during Constant-Workrate Cycling Exercise in Patients with COPD

PubMed Central

Vivodtzev, Isabelle; Gagnon, Philippe; Pepin, Véronique; Saey, Didier; Laviolette, Louis; Brouillard, Cynthia; Maltais, François

2011-01-01

Rationale The endurance time (Tend) during constant-workrate cycling exercise (CET) is highly variable in COPD. We investigated pulmonary and physiological variables that may contribute to these variations in Tend. Methods Ninety-two patients with COPD completed a CET performed at 80% of peak workrate capacity (Wpeak). Patients were divided into tertiles of Tend [Group 1: <4 min; Group 2: 4–6 min; Group 3: >6 min]. Disease severity (FEV1), aerobic fitness (Wpeak, peak oxygen consumption [ peak], ventilatory threshold [ VT]), quadriceps strength (MVC), symptom scores at the end of CET and exercise intensity during CET (heart rate at the end of CET to heart rate at peak incremental exercise ratio [HRCET/HRpeak]) were analyzed as potential variables influencing Tend. Results Wpeak, peak, VT, MVC, leg fatigue at end of CET, and HRCET/HRpeak were lower in group 1 than in group 2 or 3 (p≤0.05). VT and leg fatigue at end of CET independently predicted Tend in multiple regression analysis (r = 0.50, p = 0.001). Conclusion Tend was independently related to the aerobic fitness and to tolerance to leg fatigue at the end of exercise. A large fraction of the variability in Tend was not explained by the physiological parameters assessed in the present study. Individualization of exercise intensity during CET should help in reducing variations in Tend among patients with COPD. PMID:21386991

Inflight Exercise Regimen for the 2-Hour Prebreathe Protocol

NASA Technical Reports Server (NTRS)

Foster, Philip P.; Gernhardt, Michael L.; Woodruff, Kristin K.; Schneider, Susan M.; Homick, Jerry L. (Technical Monitor)

2000-01-01

A 10 min aerobic prebreathe exercise up to 75% V-O2(sub max) on a dual-cycle ergometer, included in the 2-hour prebreathe protocol, has been shown to dramatically reduce the incidence of decompression sickness (DCS) at altitude. In-flight only leg ergometry will be available. A balanced exercise was developed using surgical tubing with the ergometer on-orbit. We hypothesize that a 75% V02max workload, individually prescribed, would be achieved using a target heart rate to regulate the intensity of the arm exercise. VO2, heart rate (HR) / ECG, V-CO2 /V-O2, V(sub E), and V(sub T), and rate of perceived exertion (Borg scale) were measured in eleven healthy subjects who passed a US Air Force Class III Physical examination. A V-O2 peak test was performed to assess the sub-maximal exercise prescription. Two series of sub-maximal tests were performed: (1) leg ergometer/hand ergometer and (2) leg ergometer/surgical tubes. We found no significant differences (P > 0.05) in comparing the means for V-O2 and HR between the predicted and measured values during the final 4 minute-stage at "75% V-O2 workload" or between the two types of sub-maximal tests. The prescribed prebreathe sub-maximal exercise performed with flight certified surgical tubes was achieved using the target HR.

Joint Kinetics and Kinematics During Common Lower Limb Rehabilitation Exercises

PubMed Central

Comfort, Paul; Jones, Paul Anthony; Smith, Laura Constance; Herrington, Lee

2015-01-01

Context  Unilateral body-weight exercises are commonly used to strengthen the lower limbs during rehabilitation after injury, but data comparing the loading of the limbs during these tasks are limited. Objective  To compare joint kinetics and kinematics during 3 commonly used rehabilitation exercises. Design  Descriptive laboratory study. Setting  Laboratory. Patients or Other Participants  A total of 9 men (age = 22.1 ± 1.3 years, height = 1.76 ± 0.08 m, mass = 80.1 ± 12.2 kg) participated. Intervention(s)  Participants performed the single-legged squat, forward lunge, and reverse lunge with kinetic data captured via 2 force plates and 3-dimensional kinematic data collected using a motion-capture system. Main Outcome Measure(s)  Peak ground reaction forces, maximum joint angles, and peak sagittal-joint moments. Results  We observed greater eccentric and concentric peak vertical ground reaction forces during the single-legged squat than during both lunge variations (P ≤ .001). Both lunge variations demonstrated greater knee and hip angles than did the single-legged squat (P < .001), but we observed no differences between lunges (P > .05). Greater dorsiflexion occurred during the single-legged squat than during both lunge variations (P < .05), but we noted no differences between lunge variations (P = .70). Hip-joint moments were greater during the forward lunge than during the reverse lunge (P = .003) and the single-legged squat (P = .011). Knee-joint moments were greater in the single-legged squat than in the reverse lunge (P < .001) but not greater in the single-legged squat than in the forward lunge (P = .41). Ankle-joint moments were greater during the single-legged squat than during the forward lunge (P = .002) and reverse lunge (P < .001). Conclusions  Appropriate loading progressions for the hip should begin with the single-legged squat and progress to the reverse lunge and then the forward lunge. In contrast, loading progressions for the knee and ankle should begin with the reverse lunge and progress to the forward lunge and then the single-legged squat. PMID:26418958

Evaluating the influence of massage on leg strength, swelling, and pain following a half-marathon.

PubMed

Dawson, Lance G; Dawson, Kimberley A; Tiidus, Peter M

2004-11-01

Massage therapy is commonly used following endurance running races with the expectation that it will enhance post-run recovery of muscle function and reduce soreness. A limited number of studies have reported little or no influence of massage therapy on post-exercise muscle recovery. However, no studies have been conducted in a field setting to assess the potential for massage to influence muscle recovery following an actual endurance running race. To evaluate the potential for repeated massage therapy interventions to influence recovery of quadriceps and hamstring muscle soreness, recovery of quadriceps and hamstring muscle strength and reduction of upper leg muscle swelling over a two week recovery period following an actual road running race. Twelve adult recreational runners (8 male, 4 female) completed a half marathon (21.1 km) road race. On days 1,4, 8, and 11 post-race, subjects received 30 minutes of standardized massage therapy performed by a registered massage therapist on a randomly assigned massage treatment leg, while the other (control) leg received no massage treatment. Two days prior to the race (baseline) and preceding the treatments on post-race days 1, 4, 8, and 11 the following measures were conducted on each of the massage and control legs: strength of quadriceps and hamstring muscles, leg swelling, and soreness perception. At day 1, post-race quadriceps peak torque was significantly reduced (p < 0.05), and soreness and leg circumference significantly elevated (p < 0.05) relative to pre-race values with no difference between legs. This suggested that exercise-induced muscle disruption did occur. Comparing the rate of return to baseline measures between the massaged and control legs, revealed no significant differences (p > 0.05). All measures had returned to baseline at day 11. Massage did not affect the recovery of muscles in terms of physiological measures of strength, swelling, or soreness. However, questionnaires revealed that 7 of the 12 participants perceived that the massaged leg felt better upon recovery. Key PointsMassage does not appear to affect physiological indices of muscle recovery post exercise.Massage does appear to positively influence perceptions of recovery.More research needs to be completed on the purported benefits of massage.

Squat Ground Reaction Force on a Horizontal Squat Device, Free Weights, and Smith Machine

NASA Technical Reports Server (NTRS)

Scott-Pandorf, Melissa M.; Newby, Nathaniel J.; Caldwell, Erin; DeWitt, John K.; Peters, Brian T.

2010-01-01

Bed rest is an analog to spaceflight and advancement of exercise countermeasures is dependent on the development of exercise equipment that closely mimic actual upright exercise. The Horizontal Squat Device (HSD) was developed to allow a supine exerciser to perform squats that mimic upright squat exercise. PURPOSE: To compare vertical ground reaction force (GRFv) on the HSD with Free Weight (FW) or Smith Machine (SM) during squat exercise. METHODS: Subjects (3F, 3M) performed sets of squat exercise with increasing loads up to 1-repetition (rep) maximum. GRF data were collected and compared with previous GRF data for squat exercise performed with FW & SM. Loads on the HSD were adjusted to magnitudes comparable with FW & SM by subtracting the subject s body weight (BW). Peak GRFv for 45-, 55-, 64-, & 73-kg loads above BW were calculated. Percent (%) difference between HSD and the two upright conditions were computed. Effect size was calculated for the 45-kg load. RESULTS: Most subjects were unable to lift >45 kg on the HSD; however, 1 subject completed all loads. Anecdotal evidence suggested that most subjects shoulders or back failed before their legs. The mean % difference are shown. In the 45-kg condition, effect sizes were 0.37 & 0.83 (p>0.05) for HSD vs. FW and HSD vs. SM, respectively, indicating no differences between exercise modes. CONCLUSION: When BW was added to the target load, results indicated that vertical forces were similar to those in FW and SM exercise. The exercise prescription for the HSD should include a total external resistance equivalent to goal load plus subject BW. The HSD may be used as an analog to upright exercise in bed rest studies, but because most subjects were unable to lift >45 kg, it may be necessary to prescribe higher reps and lower loads to better target the leg musculature

Intoeing

MedlinePlus

... the leg bone between the knee and the ankle). Parents usually notice internal tibial torsion about the ... Exercise and Fitness Exercise Basics Sports Safety Injury Rehabilitation Emotional Well-Being Mental Health Sex and Birth ...

Near-Infrared Spectroscopic Measurement of the Effect of Leg Dominance on Muscle Oxygen Saturation During Cycling

NASA Technical Reports Server (NTRS)

Ellerby, Gwenn E. C.; Lee, Stuart M. C.; Paunescu, Lelia Adelina; Pereira, Chelsea; Smith, Charles P.; Soller, Babs R.

2011-01-01

The effect of leg dominance on the symmetry of the biomechanics during cycling remains uncertain -- asymmetries have been observed in kinematics and kinetics, while symmetries were found in muscle activation. No studies have yet investigated the symmetry of muscle metabolism during cycling. Near-infrared spectroscopy (NIRS) provides a non-invasive method to investigate the metabolic responses of specific muscles during cycling. PURPOSE: To determine whether there was an effect of leg dominance on thigh muscle oxygen saturation (SmO2) during incrementally loaded submaximal cycling using NIRS. METHODS: Eight right leg dominant, untrained subjects (5 men, 3 women; 31+/-2 yrs; 168.6+/-1.0 cm; 67.2+/-1.8 kg, mean +/- SE) volunteered to participate. Spectra were collected bilaterally from the vastus lateralis (VL) during supine rest and cycling. SmO2 was calculated using previously published methods. Subjects pedaled at 65 rpm while resistance to pedaling was increased in 0.5 kp increments from 0.5 kp every 3 min until the subject reached 80% of age-predicted maximal heart rate. SmO2 was averaged over 3 min for each completed stage. A two-way ANOVA was performed to test for leg differences. A priori contrasts were used to compare work levels to rest. RESULTS: VL SmO2 was not different between the dominant and non-dominant legs at rest and during exercise (p=0.57). How SmO2 changed with workload was also not different between legs (p=0.32). SmO2 at 0.5 kp (60.3+/-4.0, p=0.12) and 1.0 kp (59.5+/-4.0, p=0.10) was not different from rest (69.1+/-4.0). SmO2 at 1.5 kp (55.4 4.0, p=0.02), 2.0 kp (55.7+/-5.0, p=0.04), and 2.5 kp (43.4+/-7.9, p=0.01) was significantly lower than rest. CONCLUSION: VL SmO2 during cycling is not different between dominant and non-dominant legs and decreases with moderate workload in untrained cyclists. Assuming blood flow is directed equally to both legs, similar levels of oxygen extraction (as indicated by SmO2) suggests the metabolic load of cycling is not different between legs. This is in agreement with a recent study demonstrating symmetrical increase of muscle activation of the VL during cycling. Leg dominance did not influence VL SmO2 during submaximal cycling, but may have an effect at higher loads or during other forms of exercise, such as walking and running.

Active and Inactive Leg Hemodynamics during Sequential Single-Leg Interval Cycling.

PubMed

Gordon, Nicole; Abbiss, Chris R; Ihsan, Mohammed; Maiorana, Andrew J; Peiffer, Jeremiah J

2018-06-01

Leg order during sequential single-leg cycling (i.e., exercising both legs independently within a single session) may affect local muscular responses potentially influencing adaptations. This study examined the cardiovascular and skeletal muscle hemodynamic responses during double-leg and sequential single-leg cycling. Ten young healthy adults (28 ± 6 yr) completed six 1-min double-leg intervals interspersed with 1 min of passive recovery and, on a separate occasion, 12 (six with one leg followed by six with the other leg) 1-min single-leg intervals interspersed with 1 min of passive recovery. Oxygen consumption, heart rate, blood pressure, muscle oxygenation, muscle blood volume, and power output were measured throughout each session. Oxygen consumption, heart rate, and power output were not different between sets of single-leg intervals, but the average of both sets was lower than the double-leg intervals. Mean arterial pressure was higher during double-leg compared with sequential single-leg intervals (115 ± 9 vs 104 ± 9 mm Hg, P < 0.05) and higher during the initial compared with second set of single-leg intervals (108 ± 10 vs 101 ± 10 mm Hg, P < 0.05). The increase in muscle blood volume from baseline was similar between the active single leg and the double leg (267 ± 150 vs 214 ± 169 μM·cm, P = 0.26). The pattern of change in muscle blood volume from the initial to second set of intervals was significantly different (P < 0.05) when the leg was active in the initial (-52.3% ± 111.6%) compared with second set (65.1% ± 152.9%). These data indicate that the order in which each leg performs sequential single-leg cycling influences the local hemodynamic responses, with the inactive muscle influencing the stimulus experienced by the contralateral leg.

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.

Physiological and perceptual responses to incremental exercise testing in healthy men: effect of exercise test modality.

PubMed

Muscat, Kristina M; Kotrach, Houssam G; Wilkinson-Maitland, Courtney A; Schaeffer, Michele R; Mendonca, Cassandra T; Jensen, Dennis

2015-11-01

In a randomized cross-over study of 15 healthy men aged 20-30 years, we compared physiological and perceptual responses during treadmill and cycle exercise test protocols matched for increments in work rate - the source of increased locomotor muscle metabolic and contractile demands. The rates of O2 consumption and CO2 production were higher at the peak of treadmill versus cycle testing (p ≤ 0.05). Nevertheless, work rate, minute ventilation, tidal volume (VT), breathing frequency (fR), inspiratory capacity (IC), inspiratory reserve volume (IRV), tidal esophageal (Pes,tidal) and transdiaphragmatic pressure swings (Pdi,tidal), peak expiratory gastric pressures (Pga,peak), the root mean square of the diaphragm electromyogram (EMGdi,rms) expressed as a percentage of maximum EMGdi,rms (EMGdi,rms%max), and dyspnea ratings were similar at the peak of treadmill versus cycle testing (p > 0.05). Ratings of leg discomfort were higher at the peak of cycle versus treadmill exercise (p ≤ 0.05), even though peak O2 consumption was lower during cycling. Oxygen consumption, CO2 production, minute ventilation, fR, Pes,tidal, Pdi,tidal and Pga,peak were higher (p ≤ 0.05), while VT, IC, IRV, EMGdi,rms%max, and ratings of dyspnea and leg discomfort were similar (p > 0.05) at all or most submaximal work rates during treadmill versus cycle exercise. Our findings highlight important differences (and similarities) in physiological and perceptual responses at maximal and submaximal work rates during incremental treadmill and cycle exercise testing protocols. The lack of effect of exercise test modality on peak work rate advocates for the use of this readily available parameter to optimize training intensity determination, regardless of exercise training mode.

Effect of leg exercise training on vascular volumes during 30 days of 6 deg head-down bed rest

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Vernikos, J.; Wade, C. E.; Barnes, P. R.

1992-01-01

In order to investigate the effects of leg exercise training on vascular volumes during 30 d of 6-deg head-down bed rest, plasma and red cell volumes, body density, and water balance were measured in 19 men confined to bed rest (BR). One group had no exercise training (NOE), another near-maximal variable-intensity isotonic exercise (ITE) for 60 min/d, and the third near-maximal intermittent isokinetic exercise (IKE) for 60 min/d. Mean energy costs for the NOE, IKE, and ITE regimens were determined. Body densities within groups and mean urine volumes between groups were unchanged during BR. Changes in red cell volume followed changes in plasma volume. There was close coupling between resting plasma volume and plasma protein and osmotic content. It is argued that the ITE training protocol is better than the IKE protocol for maintaining plasma volume during prolonged exposure to BR.

The effect of a caffeinated energy drink on various psychological measures during submaximal cycling.

PubMed

Duncan, Michael J; Hankey, Joanne

2013-05-27

Caffeine containing energy drinks is commonly consumed in the belief that it will enhance the quality of an exercise session and enhance mood. However, studies examining their efficacy are sparse. The aim of this study was to examine the effect of a caffeinated energy drink on leg pain perception, perceived exertion, mood state and readiness to invest effort pre, during and post 60 min cycling exercise. Fourteen active individuals (7 males, 7 females, mean age ± S.D.=23.5 ± 3.5 years), completed two 60 min cycling trials at an intensity of 60% VO2 max preceded by ingestion of solutions containing either a caffeinated energy drink or placebo using a double-blind, deceptive, crossover design. During exercise, RPE (6-20 scale), leg pain (0-10 scale), heart rate (HR) and blood lactate (Bla) were recorded. Participants also completed measures of mood state and readiness to invest physical effort (RTIPE) pre- and post-exercise. Repeated measures analysis of variance was used to assess differences in all variables and across time and treatments, with gender used as a between subjects variable. Results indicate that HR was significantly higher (P=.002) from 30 to 60 min and RPE (P=.0001) and pain perception (P=.0001) were significantly lower from 20 to 60 min in the energy drink condition compared to placebo. Bla was significantly higher (P=.021) in the last 15 min of the energy drink trial and RTIPE (P=.001) increased significantly more from pre-ingestion to pre-exercise post-ingestion in the energy drink condition compared to placebo. No gender differences were evident (P>.05). The data revealed positive effects of energy drink ingestion on perception of exertion, leg muscle pain perception and readiness to invest effort during submaximal cycling in active adults. Copyright © 2013 Elsevier Inc. All rights reserved.

Validation of a dual-cycle ergometer for exercise during 100 percent oxygen prebreathing

NASA Technical Reports Server (NTRS)

Wiegman, Janet F.; Ohlhausen, John H.; Webb, James T.; Pilmanis, Andrew A.

1992-01-01

A study has been designed to determine if exercise, while prebreathing 100 percent oxygen prior to decompression, can reduce the current resting-prebreathe time requirements for extravehicular activity and high altitude reconnaissance flight. For that study, a suitable exercise mode was required. Design considerations included space limitations, cost, pressure suit compatibility, ease and maintenance of calibration, accuracy of work output, and assurance that no significant mechanical advantage or disadvantage would be introduced into the system. In addition, the exercise device must enhance denitrogenation by incorporation of both upper and lower body musculature at high levels of oxygen consumption. The purpose of this paper is to describe the specially constructed, dual-cycle ergometer developed for simultaneous arm and leg exercise during prebreathing, and to compare maximal oxygen uptake obtained on the device to that obtained during leg-only cycle ergometry and treadmill testing. Results demonstrate the suitability of the dual-cycle ergometer as an appropriate tool for exercise research during 100 percent oxygen prebreathing.

Effects of obesity on weight-bearing versus weight-supported exercise testing in patients with COPD.

PubMed

Maatman, Robbert C; Spruit, Martijn A; van Melick, Paula P; Peeters, Jos P I; Rutten, Erica P A; Vanfleteren, Lowie E G W; Wouters, Emiel F M; Franssen, Frits M E

2016-04-01

Obesity is associated with increased dyspnoea and reduced health status in patients with chronic obstructive pulmonary disease (COPD). Studies on the effects of obesity on exercise capacity showed divergent results. The objective of this study is to investigate the impact of obesity on weight-bearing versus weight-supported exercise tolerance in obese and normal weight patients, matched for age, gender and degree of airflow limitation. Retrospective analyses of data obtained during pre-pulmonary rehabilitation assessment in 108 obese COPD patients (OB) (age: 61.2 ± 5.3y, FEV1 : 43.2 ± 7.4%, BMI: 34.1 ± 3.9 kg/m(2) ,) and 108 age and FEV1 -matched normal weight COPD patients (NW) (age: 61.7 ± 3.6y, FEV1 : 41.5 ± 8.4%, BMI: 22.9 ± 1.2 kg/m(2) ,). Cardiopulmonary exercise test (CPET) and 6 min walk test (6MWT) were performed, Borg scores for dyspnoea and leg fatigue were recorded, before and after the tests. Six-minute walk distance differed between OB (398 ± 107 m) and NW patients (446 ± 109 m, P < 0.05), while peak cycling exercise load was comparable (OB: 75 ± 29 W, NW: 70 ± 25 W, ns). Dyspnoea (OB 3.2 ± 2.0 vs NW 3.1 ± 1.7, ns) and leg fatigue (OB 2.4 ± 2.3 vs NW 1.9 ± 1.7, ns) were not significantly different in OB compared with NW after 6MWT, or after CPET (dyspnoea: OB 5.1 ± 2.4 vs NW 5.4 ± 2.2, ns; leg fatigue: OB 4.0 ± 2.3 vs NW 4.0 ± 2.7, ns). In contrast to weight-supported exercise, obesity has a negative impact on weight-bearing exercise capacity, despite comparable exercise-related symptoms. The results of this study enhance the understanding of the impact of obesity on physical performance in COPD. © 2015 Asian Pacific Society of Respirology.

Muscle activity during leg strengthening exercise using free weights and elastic resistance: effects of ballistic vs controlled contractions.

PubMed

Jakobsen, Markus Due; Sundstrup, Emil; Andersen, Christoffer H; Aagaard, Per; Andersen, Lars L

2013-02-01

The present study's aim was to evaluate muscle activity during leg exercises using elastic vs. isoinertial resistance at different exertion and loading levels, respectively. Twenty-four women and eighteen men aged 26-67 years volunteered to participate in the experiment. Electromyographic (EMG) activity was recorded in nine muscles during a standardized forward lunge movement performed with dumbbells and elastic bands during (1) ballistic vs. controlled exertion, and (2) at low, medium and high loads (33%, 66% and 100% of 10 RM, respectively). The recorded EMG signals were normalized to MVC EMG. Knee joint angle was measured using electronic inclinometers. The following results were obtained. Loading intensity affected EMG amplitude in the order: low

Exercise Related Leg Pain (ERLP): a Review of The Literature

PubMed Central

2007-01-01

Exercise related leg pain (ERLP) is a regional pain syndrome described as pain between the knee and ankle which occurs with exercise. Indiscriminant use of terminology such as “shin splints” has resulted in ongoing confusion regarding the pathoanatomic entities associated with this pain syndrome. Each of the pathoanatomic entities – medial tibial stress syndrome, chronic exertional compartment syndrome, tibial and fibular stress fractures, tendinopathy, nerve entrapment, and vascular pathology – which manifest as ERLP are each described in terms of relevant anatomy, epidemiology, clinical presentation, associated pathomechanics, and intervention strategies. Evidence regarding risk factors for ERLP general and specific pathoanatomic entities are presented in the context of models of sports injury prevention. PMID:21522213

Association between Changes in Muscle Quality with Exercise Training and Changes in Cardiorespiratory Fitness Measures in Individuals with Type 2 Diabetes Mellitus: Results from the HART-D Study.

PubMed

Sénéchal, Martin; Johannsen, Neil M; Swift, Damon L; Earnest, Conrad P; Lavie, Carl J; Blair, Steven N; Church, Timothy S

2015-01-01

Type 2 diabetes mellitus (T2DM) is associated with a reduction in muscle quality. However, there is inadequate empirical evidence to determine whether changes in muscle quality following exercise are associated with improvement in cardiorespiratory fitness (CRF) in individuals with T2DM. The objective of this study was to investigate the association between change in muscle quality following a 9-month intervention of aerobic training (AT), resistance training (RT) or a combination of both (ATRT) and cardiorespiratory fitness (CRF) in individuals with T2DM. A total of 196 participants were randomly assigned to a control, AT, RT, or combined ATRT for a 9-months intervention. The exposure variable was change in muscle quality [(Post: leg muscle strength/leg muscle mass)-[(Pre: leg muscle strength/leg muscle mass)]. Dependent variables were change in CRF measures including absolute and relative VO2peak, and treadmill time to exhaustion (TTE) and estimated metabolic equivalent task (METs). Continuous change in muscle quality was independently associated with change in absolute (β = 0.015; p = 0.019) and relative (β = 0.200; p = 0.005) VO2peak, and TTE (β = 0.170; p = 0.043), but not with estimated METs (p > 0.05). A significant trend was observed across tertiles of change in muscle quality for changes in absolute (β = 0.050; p = 0.005) and relative (β = 0.624; p = 0.002) VO2peak following 9 months of exercise training. No such association was observed for change in TTE and estimated METs (p > 0.05). The results from this ancillary study suggest that change in muscle quality following exercise training is associated with a greater improvement in CRF in individuals with T2DM. Given the effect RT has on increasing muscle quality, especially as part of a recommended training program (ATRT), individuals with T2DM should incorporate RT into their AT regimens to optimize CRF improvement. Clinicaltrials.gov NCT00458133.

Association between Changes in Muscle Quality with Exercise Training and Changes in Cardiorespiratory Fitness Measures in Individuals with Type 2 Diabetes Mellitus: Results from the HART-D Study

PubMed Central

Sénéchal, Martin; Johannsen, Neil M.; Swift, Damon L.; Earnest, Conrad P.; Lavie, Carl J.; Blair, Steven N.; Church, Timothy S.

2015-01-01

Introduction Type 2 diabetes mellitus (T2DM) is associated with a reduction in muscle quality. However, there is inadequate empirical evidence to determine whether changes in muscle quality following exercise are associated with improvement in cardiorespiratory fitness (CRF) in individuals with T2DM. The objective of this study was to investigate the association between change in muscle quality following a 9-month intervention of aerobic training (AT), resistance training (RT) or a combination of both (ATRT) and cardiorespiratory fitness (CRF) in individuals with T2DM. Material and Methods A total of 196 participants were randomly assigned to a control, AT, RT, or combined ATRT for a 9-months intervention. The exposure variable was change in muscle quality [(Post: leg muscle strength/leg muscle mass)-[(Pre: leg muscle strength/leg muscle mass)]. Dependent variables were change in CRF measures including absolute and relative VO2peak, and treadmill time to exhaustion (TTE) and estimated metabolic equivalent task (METs). Results Continuous change in muscle quality was independently associated with change in absolute (β = 0.015; p = 0.019) and relative (β = 0.200; p = 0.005) VO2peak, and TTE (β = 0.170; p = 0.043), but not with estimated METs (p > 0.05). A significant trend was observed across tertiles of change in muscle quality for changes in absolute (β = 0.050; p = 0.005) and relative (β = 0.624; p = 0.002) VO2peak following 9 months of exercise training. No such association was observed for change in TTE and estimated METs (p > 0.05). Discussion The results from this ancillary study suggest that change in muscle quality following exercise training is associated with a greater improvement in CRF in individuals with T2DM. Given the effect RT has on increasing muscle quality, especially as part of a recommended training program (ATRT), individuals with T2DM should incorporate RT into their AT regimens to optimize CRF improvement. Trial Registration Clinicaltrials.gov NCT00458133 PMID:26252477

Effect of selected exercises on in-shoe plantar pressures in people with diabetes and peripheral neuropathy

PubMed Central

Shah, Kshamata M.; Mueller, Michael J.

2012-01-01

BACKGROUND In people with diabetes and peripheral neuropathy (DM+PN), injury risk is not clearly known for weight bearing (WB) vs. non-weight bearing (NWB) exercise. In-shoe peak plantar pressures (PPP) often are used as a surrogate indicator of injury to the insensitive foot. OBJECTIVE Compare PPPs in people with DM+PN during selected WB and NWB exercises. METHODS 15 subjects with DM+PN participated. PPPs were recorded for the forefoot, midfoot, and heel during level walking and compared to; WB exercises - treadmill walking, heel and toe raises, sit to stands, stair climbing, single leg standing; and NWB exercises - stationary bicycling, balance ball exercise and plantar flexion exercise. RESULTS Compared to level walking; mean forefoot PPP during treadmill walking was 13% higher, but this difference was eliminated when walking speed was used as a covariate. Mean PPPs were similar or substantially lower for other exercises, except for higher forefoot PPP with heel raise exercises. CONCLUSIONS Slow progression and regular monitoring of insensitive feet are recommended for all exercises, but especially for heel raises, and increases in walking speed. The remaining WB and NWB exercises pose no greater risk to the insensitive foot due to increases in PPP compared to level walking. PMID:22677098

Blood ammonia and lactate as markers of muscle metabolites during leg press exercise.

PubMed

Gorostiaga, Esteban M; Navarro-Amézqueta, Ion; Calbet, Jose A L; Sánchez-Medina, Luis; Cusso, Roser; Guerrero, Mario; Granados, Cristina; González-Izal, Miriam; Ibáñez, Javier; Izquierdo, Mikel

2014-10-01

To examine whether blood lactate and ammonia concentrations can be used to estimate the functional state of the muscle contractile machinery with regard to muscle lactate and adenosine triphosphate (ATP) levels during leg press exercise. Thirteen men (age, 34 ± 5 years; 1 repetition maximum leg press strength 199 ± 33 kg) performed either 5 sets of 10 repetitions to failure (5×10RF), or 10 sets of 5 repetitions not to failure (10×5RNF) with the same initial load (10RM) and interset rests (2 minutes) on 2 separate sessions in random order. Capillary blood samples were obtained before and during exercise and recovery. Six subjects underwent vastus lateralis muscle biopsies at rest, before the first set and after the final exercise set. The 5×10RF resulted in a significant and marked decrease in power output (37%), muscle ATP content (24%), and high levels of muscle lactate (25.0 ± 8.1 mmol·kg wet weight), blood lactate (10.3 ± 2.6 mmol·L), and blood ammonia (91.6 ± 40.5 μmol·L). During 10×5RNF no or minimal changes were observed. Significant correlations were found between: (a) blood ammonia and muscle ATP (r = -0.75), (b) changes in peak power output and blood ammonia (r = -0.87) and blood lactate (r = -0.84), and (c) blood and muscle lactate (r = 0.90). Blood lactate and ammonia concentrations can be used as extracellular markers for muscle lactate and ATP contents, respectively. The decline in mechanical power output can be used to indirectly estimate blood ammonia and lactate during leg press exercise.

[The concept and definition of locomotive syndrome in a super-aged society].

PubMed

Nakamura, Kozo; Yoshimura, Noriko; Akune, Toru; Ogata, Toru; Tanaka, Sakae

2014-10-01

The population of elderly individuals who need nursing care is rapidly increasing in Japan. Locomotive syndrome involves a decrease in mobility due to locomotive organ dysfunction, and increases risk for dependency on nursing care service. Because gait speed and chair stand time are correlated with such risks, patients with locomotive syndrome are assessed using brief methods such as the two-step test, which involves dividing the maximum stride length by the height of the patient, and the stand-up test, which involves standing on one or both legs at different heights. One leg standing and squatting are recommended as beneficial locomotive home exercises. Locomotive syndrome has been recognized widely in Japan, and included in the National Health Promotion Movement (2013-2022).

Cardiovascular control during whole body exercise

PubMed Central

Secher, Niels H.

2016-01-01

It has been considered whether during whole body exercise the increase in cardiac output is large enough to support skeletal muscle blood flow. This review addresses four lines of evidence for a flow limitation to skeletal muscles during whole body exercise. First, even though during exercise the blood flow achieved by the arms is lower than that achieved by the legs (∼160 vs. ∼385 ml·min−1·100 g−1), the muscle mass that can be perfused with such flow is limited by the capacity to increase cardiac output (42 l/min, highest recorded value). Secondly, activation of the exercise pressor reflex during fatiguing work with one muscle group limits flow to other muscle groups. Another line of evidence comes from evaluation of regional blood flow during exercise where there is a discrepancy between flow to a muscle group when it is working exclusively and when it works together with other muscles. Finally, regulation of peripheral resistance by sympathetic vasoconstriction in active muscles by the arterial baroreflex is critical for blood pressure regulation during exercise. Together, these findings indicate that during whole body exercise muscle blood flow is subordinate to the control of blood pressure. PMID:27311439

Cardiovascular control during whole body exercise.

PubMed

Volianitis, Stefanos; Secher, Niels H

2016-08-01

It has been considered whether during whole body exercise the increase in cardiac output is large enough to support skeletal muscle blood flow. This review addresses four lines of evidence for a flow limitation to skeletal muscles during whole body exercise. First, even though during exercise the blood flow achieved by the arms is lower than that achieved by the legs (∼160 vs. ∼385 ml·min(-1)·100 g(-1)), the muscle mass that can be perfused with such flow is limited by the capacity to increase cardiac output (42 l/min, highest recorded value). Secondly, activation of the exercise pressor reflex during fatiguing work with one muscle group limits flow to other muscle groups. Another line of evidence comes from evaluation of regional blood flow during exercise where there is a discrepancy between flow to a muscle group when it is working exclusively and when it works together with other muscles. Finally, regulation of peripheral resistance by sympathetic vasoconstriction in active muscles by the arterial baroreflex is critical for blood pressure regulation during exercise. Together, these findings indicate that during whole body exercise muscle blood flow is subordinate to the control of blood pressure. Copyright © 2016 the American Physiological Society.

Increasing blood flow to exercising muscle attenuates systemic cardiovascular responses during dynamic exercise in humans

PubMed Central

Ichinose-Kuwahara, Tomoko; Kondo, Narihiko; Nishiyasu, Takeshi

2015-01-01

Reducing blood flow to working muscles during dynamic exercise causes metabolites to accumulate within the active muscles and evokes systemic pressor responses. Whether a similar cardiovascular response is elicited with normal blood flow to exercising muscles during dynamic exercise remains unknown, however. To address that issue, we tested whether cardiovascular responses are affected by increases in blood flow to active muscles. Thirteen healthy subjects performed dynamic plantarflexion exercise for 12 min at 20%, 40%, and 60% of peak workload (EX20, EX40, and EX60) with their lower thigh enclosed in a negative pressure box. Under control conditions, the box pressure was the same as the ambient air pressure. Under negative pressure conditions, beginning 3 min after the start of the exercise, the box pressure was decreased by 20, 45, and then 70 mmHg in stepwise fashion with 3-min step durations. During EX20, the negative pressure had no effect on blood flow or the cardiovascular responses measured. However, application of negative pressure increased blood flow to the exercising leg during EX40 and EX60. This increase in blood flow had no significant effect on systemic cardiovascular responses during EX40, but it markedly attenuated the pressor responses otherwise seen during EX60. These results demonstrate that during mild exercise, normal blood flow to exercising muscle is not a factor eliciting cardiovascular responses, whereas it elicits an important pressor effect during moderate exercise. This suggests blood flow to exercising muscle is a major determinant of cardiovascular responses during dynamic exercise at higher than moderate intensity. PMID:26377556

Effects of Wii balance board exercises on balance after posterior cruciate ligament reconstruction.

PubMed

Puh, Urška; Majcen, Nia; Hlebš, Sonja; Rugelj, Darja

2014-05-01

To establish the effects of training on Wii balance board (WBB) after posterior cruciate ligament (PCL) reconstruction on balance. Included patient injured her posterior cruciate ligament 22 months prior to the study. Training on WBB was performed 4 weeks, 6 times per week, 30-45 min per day. Center of pressure (CoP) sway during parallel and one-leg stance, and body weight distribution in parallel stance were measured. Additionally, measurements of joint range of motion and limb circumferences were taken before and after training. After training, the body weight was almost equally distributed on both legs. Decrease in CoP sway was most significant for one-leg stance with each leg on compliant surface with eyes open and closed. The knee joint range of motion increased and limb circumferences decreased. According to the results of this single case report, we might recommend the use of WBB for balance training after PCL reconstruction. Case series with no comparison group, Level IV.

Immediate Effects of Kinesiology Taping of Quadriceps on Motor Performance after Muscle Fatigued Induction.

PubMed

Ahn, Ick Keun; Kim, You Lim; Bae, Young-Hyeon; Lee, Suk Min

2015-01-01

Objectives. The purpose of this cross-sectional single-blind study was to investigate the immediate effects of Kinesiology taping of quadriceps on motor performance after muscle fatigued induction. Design. Randomized controlled cross-sectional design. Subjects. Forty-five subjects participated in this study. Participants were divided into three groups: Kinesiology taping group, placebo taping group, and nontaping group. Methods. Subjects performed short-term exercise for muscle fatigued induction, followed by the application of each intervention. Peak torque test, one-leg single hop test, active joint position sense test, and one-leg static balance test were carried out before and after the intervention. Results. Peak torque and single-leg hopping distance were significantly increased when Kinesiology taping was applied (p < 0.05). But there were no significant effects on active joint position sense and single-leg static balance. Conclusions. We proved that Kinesiology taping is effective in restoring muscle power reduced after muscle fatigued induction. Therefore, we suggest that Kinesiology taping is beneficial for fatigued muscles.

Arterial blood pressure response to heavy resistance exercise.

PubMed

MacDougall, J D; Tuxen, D; Sale, D G; Moroz, J R; Sutton, J R

1985-03-01

The purpose of this study was to record the blood pressure response to heavy weight-lifting exercise in five experienced body builders. Blood pressure was directly recorded by means of a capacitance transducer connected to a catheter in the brachial artery. Intrathoracic pressure with the Valsalva maneuver was recorded as mouth pressure by having the subject maintain an open glottis while expiring against a column of Hg during the lifts. Exercises included single-arm curls, overhead presses, and both double- and single-leg presses performed to failure at 80, 90, 95, and 100% of maximum. Systolic and diastolic blood pressures rose rapidly to extremely high values during the concentric contraction phase for each lift and declined with the eccentric contraction. The greatest peak pressures occurred during the double-leg press where the mean value for the group was 320/250 mmHg, with pressures in one subject exceeding 480/350 mmHg. Peak pressures with the single-arm curl exercise reached a mean group value of 255/190 mmHg when repetitions were continued to failure. Mouth pressures of 30-50 Torr during a single maximum lift, or as subjects approached failure with a submaximal weight, indicate that a portion of the observed increase in blood pressure was caused by a Valsalva maneuver. It was concluded that when healthy young subjects perform weight-lifting exercises the mechanical compression of blood vessels combines with a potent pressor response and a Valsalva response to produce extreme elevations in blood pressure. Pressures are extreme even when exercise is performed with a relatively small muscle mass.

How performing a repetitive one-legged stance modifies two-legged postural control.

PubMed

Burdet, Cyril; Vuillerme, Nicolas; Rougier, Patrice R

2011-10-01

The proprioceptive cues in the control of movement is recognized as playing a major role in postural control. However, little is known about its possible increased contribution to postural control consecutive to repetitive muscular activations. To test this, the short-term effects induced by a 1-legged exercise on 2-legged postural control with the eyes closed were assessed in healthy subjects. The center-of-pressure (CP) displacements obtained using a force platform were split into 2 elementary movements: center-of-gravity vertical projection (CGv) and the difference (CP - CGv). These movements assessed the net postural performance and the level of neuromuscular activity, respectively, and were processed afterward (a) through variances, mean velocity, and the average surface covered by the trajectories and (b) a fractional Brownian motion (fBm) modeling. The latter provides further information about how much the subject controls the movements and the spatiotemporal relation between the successive control mechanisms. No difference was found using the classical parameters. In contrast, fBm parameters showed statistically significant changes in postural control after 1-legged exercises: The spatial and temporal coordinates of the transition points for the CG movements along the anteroposterior axis are decreased. Because the body movement control does not rely on visual or vestibular cues, this ability to trigger the corrective process of the CG movements more quickly in the postexercise condition and once a more reduced distance has been covered emphasizes how prior muscular activation improves body movement detection. As a general rule, these data show that the motor systems control body motions better after repetitive stimulation of the sensory cues. These insights should be of interest in physical activities based on a precise muscular length control.

Warm-up with a weighted vest improves running performance via leg stiffness and running economy.

PubMed

Barnes, K R; Hopkins, W G; McGuigan, M R; Kilding, A E

2015-01-01

To determine the effects of "strides" with a weighted-vest during a warm-up on endurance performance and its potential neuromuscular and metabolic mediators. A bout of resistance exercise can enhance subsequent high-intensity performance, but little is known about such priming exercise for endurance performance. A crossover with 5-7 days between an experimental and control trial was performed by 11 well-trained distance runners. Each trial was preceded by a warm-up consisting of a 10-min self-paced jog, a 5-min submaximal run to determine running economy, and six 10-s strides with or without a weighted-vest (20% of body mass). After a 10-min recovery period, runners performed a series of jumps to determine leg stiffness and other neuromuscular characteristics, another 5-min submaximal run, and an incremental treadmill test to determine peak running speed. Clinical and non-clinical forms of magnitude-based inference were used to assess outcomes. Correlations and linear regression were used to assess relationships between performance and underlying measures. The weighted-vest condition resulted in a very-large enhancement of peak running speed (2.9%; 90% confidence limits ±0.8%), a moderate increase in leg stiffness (20.4%; ±4.2%) and a large improvement in running economy (6.0%; ±1.6%); there were also small-moderate clear reductions in cardiorespiratory measures. Relationships between change scores showed that changes in leg stiffness could explain all the improvements in performance and economy. Strides with a weighted-vest have a priming effect on leg stiffness and running economy. It is postulated the associated major effect on peak treadmill running speed will translate into enhancement of competitive endurance performance. Copyright © 2013 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Exercise training, but not resveratrol, improves metabolic and inflammatory status in skeletal muscle of aged men

PubMed Central

Olesen, Jesper; Gliemann, Lasse; Biensø, Rasmus; Schmidt, Jakob; Hellsten, Ylva; Pilegaard, Henriette

2014-01-01

The aim was to investigate the metabolic and anti-inflammatory effects of resveratrol alone and when combined with exercise training in skeletal muscle of aged human subjects. Healthy, physically inactive men (60–72 years old) were randomized to either 8 weeks of daily intake of 250 mg resveratrol or placebo or to 8 weeks of high-intensity exercise training with 250 mg resveratrol or placebo. Before and after the interventions, resting blood samples and muscle biopsies were obtained and a one-legged knee-extensor endurance exercise test was performed. Exercise training increased skeletal muscle peroxisome proliferator-activated receptor-γ co-activator-1α mRNA ∼1.5-fold, cytochrome c protein ∼1.3-fold, cytochrome c oxidase I protein ∼1.5-fold, citrate synthase activity ∼1.3-fold, 3-hydroxyacyl-CoA dehydrogenase activity ∼1.3-fold, inhibitor of κB-α and inhibitor of κB-β protein content ∼1.3-fold and time to exhaustion in the one-legged knee-extensor endurance exercise test by ∼1.2-fold, with no significant additive or adverse effects of resveratrol on these parameters. Despite an overall ∼25% reduction in total acetylation level in skeletal muscle with resveratrol, no exclusive resveratrol-mediated metabolic effects were observed on the investigated parameters. Notably, however, resveratrol blunted an exercise training-induced decrease (∼20%) in protein carbonylation and decrease (∼40%) in tumour necrosis factor α mRNA content in skeletal muscle. In conclusion, resveratrol did not elicit metabolic improvements in healthy aged subjects; in fact, resveratrol even impaired the observed exercise training-induced improvements in markers of oxidative stress and inflammation in skeletal muscle. Collectively, this highlights the metabolic efficacy of exercise training in aged subjects and does not support the contention that resveratrol is a potential exercise mimetic in healthy aged subjects. PMID:24514907

Effect of resistance exercise training combined with relatively low vascular occlusion.

PubMed

Sumide, Takahiro; Sakuraba, Keishoku; Sawaki, Keisuke; Ohmura, Hirotoshi; Tamura, Yoshifumi

2009-01-01

Previous studies have demonstrated that a low-intensity resistance exercise, combined with vascular occlusion, results in a marked increase in muscular size and strength. We investigated the optimal pressure for reduction of muscle blood flow with resistance exercise to increase the muscular strength and endurance. Twenty-one subjects were randomly divided into four groups by the different application of vascular occlusion pressure at the proximal of thigh: without any pressure (0-pressure group), with a pressure of 50mmHg (50-pressure group), with a pressure of 150mmHg (150-pressure group), and with a pressure of 250mmHg (250-pressure group). The isokinetic muscle strength at angular velocities of 60 and 180 degrees /s, total muscle work, and the cross-sectional knee extensor muscle area were assessed before and after exercise. Exercise was performed three times a week over an 8-week period at an intensity of approximately 20% of one-repetition maximum for straight leg raising and hip joint adduction and maximum force for abduction training. A significant increase in strength at 180 degrees /s was noted after exercise in all subjects who exercised under vascular occlusion. Total muscle work increased significantly in the 50- and 150-pressure groups (P<0.05, P<0.01, respectively). There was no significant increase in cross-sectional knee extensor muscle area in any groups. In conclusion, resistance exercise with relatively low vascular occlusion pressure is potentially useful to increase muscle strength and endurance without discomfort.

Advice to Stay Active or Structured Exercise in the Management of Sciatica: A Systematic Review and Meta-analysis.

PubMed

Fernandez, Matt; Hartvigsen, Jan; Ferreira, Manuela L; Refshauge, Kathryn M; Machado, Aryane F; Lemes, Ítalo R; Maher, Chris G; Ferreira, Paulo H

2015-09-15

A systematic review and meta-analysis. To evaluate the evidence on comparative effectiveness of advice to stay active versus supervised structured exercise in the management of sciatica. Conservative management of sciatica usually includes interventions to promote physical activity in the form of advice to stay active or exercise, but there has been no systematic review directly comparing the effectiveness of these 2 approaches. Data Sources included MEDLINE, CINAHL, EMBASE, and PEDro databases. Studies were randomized controlled trials comparing advice with exercise. Two independent reviewers extracted data and assessed methodological quality using the PEDro scale. Pain and disability data were extracted for all time points and converted to a common 0 to 100 scale. Data were pooled with a random effects model for short, intermediate, and long-term follow-ups. The GRADE approach was used to summarize the strength of evidence. Five trials were included in the meta-analysis, which showed a significant, although small effect favoring exercise over advice for reducing leg pain intensity in the short term (weighted mean difference: 11.43 [95% confidence interval, 0.71-22.16]) but no difference for disability (weighted mean difference: 1.45 [95% confidence interval, -2.86 to 5.76]). Furthermore, there was no difference at intermediate and long-term follow-ups between advice and exercise for patient-relevant outcomes. There is low-quality evidence (GRADE) that exercise provides small, superior effects compared with advice to stay active on leg pain in the short term for patients experiencing sciatica. However, there is moderate-quality evidence showing no difference between advice to stay active and exercise on leg pain and disability status in people with sciatica in the long term. 1.

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.

Dehydration reduces left ventricular filling at rest and during exercise independent of twist mechanics.

PubMed

Stöhr, Eric J; González-Alonso, José; Pearson, James; Low, David A; Ali, Leena; Barker, Horace; Shave, Rob

2011-09-01

The purpose of this study was to determine whether the reduction in stroke volume (SV), previously shown to occur with dehydration and increases in internal body temperatures during prolonged exercise, is caused by a reduction in left ventricular (LV) function, as indicated by LV volumes, strain, and twist ("LV mechanics"). Eight healthy men [age: 20 ± 2, maximal oxygen uptake (VO₂max): 58 ± 7 ml·kg⁻¹·min⁻¹] completed two, 1-h bouts of cycling in the heat (35°C, 50% peak power) without fluid replacement, resulting in 2% and 3.5% dehydration, respectively. Conventional and two-dimensional speckle-tracking echocardiography was used to determine LV volumes, strain, and twist at rest and during one-legged knee-extensor exercise at baseline, both levels of dehydration, and following rehydration. Progressive dehydration caused a significant reduction in end-diastolic volume (EDV) and SV at rest and during one-legged knee-extensor exercise (rest: Δ-33 ± 14 and Δ-21 ± 14 ml, respectively; exercise: Δ-30 ± 10 and Δ-22 ± 9 ml, respectively, during 3.5% dehydration). In contrast to the marked decline in EDV and SV, systolic and diastolic LV mechanics were either maintained or even enhanced with dehydration at rest and during knee-extensor exercise. We conclude that dehydration-induced reductions in SV at rest and during exercise are the result of reduced LV filling, as reflected by the decline in EDV. The concomitant maintenance of LV mechanics suggests that the decrease in LV filling, and consequently ejection, is likely caused by the reduction in blood volume and/or diminished filling time rather than impaired LV function.

Impact of dehydration on a full body resistance exercise protocol.

PubMed

Kraft, Justin A; Green, James M; Bishop, Phillip A; Richardson, Mark T; Neggers, Yasmin H; Leeper, James D

2010-05-01

This study examined effects of dehydration on a full body resistance exercise workout. Ten males completed two trials: heat exposed (with 100% fluid replacement) (HE) and dehydration (approximately 3% body mass loss with no fluid replacement) (DEHY) achieved via hot water bath (approximately 39 degrees C). Following HE and DEHY, participants performed three sets to failure (using predetermined 12 repetition maximum) of bench press, lat pull down, overhead press, barbell curl, triceps press, and leg press with a 2-min recovery between each set and 2 min between exercises. A paired t test showed total repetitions (all sets combined) were significantly lower for DEHY: (144.1 +/- 26.6 repetitions) versus HE: (169.4 +/- 29.1 repetitions). ANOVAs showed significantly lower repetitions (approximately 1-2 repetitions on average) per exercise for DEHY versus HE (all exercises). Pre-set rate of perceived exertion (RPE) and pre-set heart rate (HR) were significantly higher [approximately 0.6-1.1 units on average in triceps press, leg press, and approached significance in lat pull down (P = 0.14) and approximately 6-13 b min(-1) on average in bench press, lat pull down, triceps press, and approached significance for overhead press (P = 0.10)] in DEHY versus HE. Session RPE difference approached significance (DEHY: 8.6 +/- 1.9, HE: 7.4 +/- 2.3) (P = 0.12). Recovery HR was significantly higher for DEHY (116 +/- 15 b min(-1)) versus HE (105 +/- 13 b min(-1)). Dehydration (approximately 3%) impaired resistance exercise performance, decreased repetitions, increased perceived exertion, and hindered HR recovery. Results highlight the importance of adequate hydration during full body resistance exercise sessions.

Expiratory muscle loading increases intercostal muscle blood flow during leg exercise in healthy humans

PubMed Central

Athanasopoulos, Dimitris; Louvaris, Zafeiris; Cherouveim, Evgenia; Andrianopoulos, Vasilis; Roussos, Charis; Zakynthinos, Spyros

2010-01-01

We investigated whether expiratory muscle loading induced by the application of expiratory flow limitation (EFL) during exercise in healthy subjects causes a reduction in quadriceps muscle blood flow in favor of the blood flow to the intercostal muscles. We hypothesized that, during exercise with EFL quadriceps muscle blood flow would be reduced, whereas intercostal muscle blood flow would be increased compared with exercise without EFL. We initially performed an incremental exercise test on eight healthy male subjects with a Starling resistor in the expiratory line limiting expiratory flow to ∼ 1 l/s to determine peak EFL exercise workload. On a different day, two constant-load exercise trials were performed in a balanced ordering sequence, during which subjects exercised with or without EFL at peak EFL exercise workload for 6 min. Intercostal (probe over the 7th intercostal space) and vastus lateralis muscle blood flow index (BFI) was calculated by near-infrared spectroscopy using indocyanine green, whereas cardiac output (CO) was measured by an impedance cardiography technique. At exercise termination, CO and stroke volume were not significantly different during exercise, with or without EFL (CO: 16.5 vs. 15.2 l/min, stroke volume: 104 vs. 107 ml/beat). Quadriceps muscle BFI during exercise with EFL (5.4 nM/s) was significantly (P = 0.043) lower compared with exercise without EFL (7.6 nM/s), whereas intercostal muscle BFI during exercise with EFL (3.5 nM/s) was significantly (P = 0.021) greater compared with that recorded during control exercise (0.4 nM/s). In conclusion, increased respiratory muscle loading during exercise in healthy humans causes an increase in blood flow to the intercostal muscles and a concomitant decrease in quadriceps muscle blood flow. PMID:20507965

Effects of elastic band exercises on physical ability and muscular topography of elderlyfemales.

PubMed

Lee, Jung Won; Kim, Suk Bum; Kim, Seong Wook

2018-02-01

[Purpose] This study examined the effects of band exercise types on the physical ability and muscular topography for elderly females. [Subjects and Methods] Twenty-six females older than 65 years were divided into the dynamic band exercise (DBE; n=13) group and the Static band exercise (SBE; n=13) group. Each participant performed 12 weeks of elastic band exercises. Physical abilities were measured by leg extension power, sitting trunk flexion, closed eyes foot balance, and time to get up. Changes in muscle topography were evaluated with Moire measurement equipment for the chest, abdomen, and lumbar region. All results were compared before and after 12 weeks of exercise. [Results] Changes in physical ability were significantly increased in both groups. The scores for the muscular topography of the chest, abdomen, lumbar region, and all body parts was significantly improved in both groups for closed eyes foot balance. There were more improvements in the DBE group. [Conclusion] Two types of static and dynamic elastic band exercises effectively changed the physical fitness and muscle topography of elderly females. Therefore, to increase the effects of exercise, dynamic band exercises are considered useful. Because band exercises are simple, they can be used to maintain the health of elderly people.

Biomechanical analysis of the single‐leg decline squat

PubMed Central

Zwerver, J; Bredeweg, S W; Hof, A L

2007-01-01

Background The single‐leg squat on a 25° decline board has been described as a clinical assessment tool and as a rehabilitation exercise for patients with patellar tendinopathy. Several assumptions have been made about its working mechanism on patellar load and patellofemoral forces, but these are not substantiated by biomechanical evaluations. Aim To investigate knee moment and patellofemoral contact force as a function of decline angle in the single‐leg squat. Methods Five subjects performed single‐leg eccentric squats at decline angles of 0°, 5°, 10°, 15°, 20° and 25° (with/without a backpack of 10 kg), and 30° on a board that was placed over a forceplate. Kinematic and forceplate data were recorded by the Optotrak system. Joint moments of ankle, knee and hip were calculated by two‐dimensional inverse dynamics. Results Knee moment increased by 40% at decline angles of 15° and higher, whereas hip and ankle moment decreased. Maximum knee and ankle angles increased with steeper decline. With a 10 kg backpack at 25° decline, the knee moment was 23% higher than unloaded. Both patellar tendon and patellofemoral forces increased with higher decline angles, but beyond 60°, the patellofemoral force rose steeper than the tendon force. Conclusions All single‐leg squats at decline angles >15° result in 40% increase in maximum patellar tendon force. In knee flexions >60°, patellofemoral forces increase more than patellar tendon forces. Higher tendon load can be achieved by the use of a backpack with extra weight. PMID:17224441

Strength, body composition, and functional outcomes in the squat versus leg press exercises.

PubMed

Rossi, Fabrício E; Schoenfeld, Brad J; Ocetnik, Skyler; Young, Jonathan; Vigotsky, Andrew; Contreras, Bret; Krieger, James W; Miller, Michael G; Cholewa, Jason

2018-03-01

The purpose of this study was to compare strength, body composition, and functional outcome measures following performance of the back squat, leg press, or a combination of the two exercises. Subjects were pair-matched based on initial strength levels and then randomly assigned to 1 of 3 groups: a squat-only group (SQ) that solely performed squats for the lower body; a leg press-only group (LP) that solely performed leg presses for the lower body, or a combined squat and leg press group (SQ-LP) that performed both squats and leg presses for the lower body. All other RT variables were held constant. The study period lasted 10 weeks with subjects performing 2 lower body workouts per week comprising 6 sets per session at loads corresponding to 8-12 RM with 90- to 120-second rest intervals. Results showed that SQ had greater transfer to maximal squat strength compared to the leg press. Effect sizes favored SQ and SQ-LP versus LP with respect to countermovement jump while greater effect sizes for dynamic balance were noted for SQ-LP and LP compared to SQ, although no statistical differences were noted between conditions. These findings suggest that both free weights and machines can improve functional outcomes, and that the extent of transfer may be specific to the given task.

Function of human eccrine sweat glands during dynamic exercise and passive heat stress

NASA Technical Reports Server (NTRS)

Kondo, N.; Shibasaki, M.; Aoki, K.; Koga, S.; Inoue, Y.; Crandall, C. G.

2001-01-01

The purpose of this study was to identify the pattern of change in the density of activated sweat glands (ASG) and sweat output per gland (SGO) during dynamic constant-workload exercise and passive heat stress. Eight male subjects (22.8 +/- 0.9 yr) exercised at a constant workload (117.5 +/- 4.8 W) and were also passively heated by lower-leg immersion into hot water of 42 degrees C under an ambient temperature of 25 degrees C and relative humidity of 50%. Esophageal temperature, mean skin temperature, sweating rate (SR), and heart rate were measured continuously during both trials. The number of ASG was determined every 4 min after the onset of sweating, whereas SGO was calculated by dividing SR by ASG. During both exercise and passive heating, SR increased abruptly during the first 8 min after onset of sweating, followed by a slower increase. Similarly for both protocols, the number of ASG increased rapidly during the first 8 min after the onset of sweating and then ceased to increase further (P > 0.05). Conversely, SGO increased linearly throughout both perturbations. Our results suggest that changes in forearm sweating rate rely on both ASG and SGO during the initial period of exercise and passive heating, whereas further increases in SR are dependent on increases in SGO.

[Maximal exercise in spinal cord injured subjects: effects of an antigravity suit].

PubMed

Bazzi-Grossin, C; Bonnin, P; Bailliart, O; Bazzi, H; Kedra, A W; Martineaud, J P

1996-01-01

Paraplegics have low aerobic capacity because of the spinal cord injury. Their functional muscle mass is reduced and usually untrained. They have to use upperbody muscles for displacements and daily activities. Sympathic nervous system injury is responsible of vasomotricity disturbances in leg vessels and possible abdominal vessels, proportionally to level injury. If cord injury level is higher than T5, then sympathic cardiac efferences may be damaged. Underbody muscles atrophy and vasomotricity disturbances contribute to phlebostasis. This stasis may decrease venous return, preload and stroke volume (Starling). To maintain appropriate cardiac output, tachycardia is necessary, especially during exercise. Low stroke volume, all the more since it is associated with cardio-acceleration disturbances, may reduce cardiac output reserve, and so constitutes a limiting factor for adaptation to exercise. The aim of this study was to verify if use of an underlesional pressure suit may increase cardiac output reserve because of lower venous stasis, and increase performance. We studied 10 able-bodied and 14 traumatic paraplegic subjects. Able-bodied subjects were 37 +/- 6 years old, wellbeing, not especially trained with upperbody muscles: there were 2 women and 8 men. Paraplegics were 27 +/- 7 years old, wellbeing except paraplegia, five of them practiced sport regularly (athletism or basket for disabled), and the others just daily propelled their wheelchair; there were 5 women and 9 men. For 8 of them, cord injury levels were located below T7, between T1 and T6 for the others. The age disability varied from 6 months to 2 years for 9 of them, it was approximately five years for 4 of them, and 20 years for one. We used a maximal triangular arm crank exercise with an electro-magnetic ergocycle Gauthier frame. After five minutes warm up, it was proceeded in one minute successive stages until maximal oxygen consumption is raised. VO2, VCO2, RER were measured by direct method with an Ergostar analyser every 30 seconds. Heart rate was registered continuously using a cardio-frequence-meter Baumann, and ECG was observed on a Cardiovit electro-cardiograph. Each subject reached maximal exercises on different days: one without any contention, and the other one with abdomen and legs contention using an antigravity suit, inflated to 45-50 mm Hg for legs and 30-40 mm Hg for abdomen. The able-bodied subjects VO2 peak was 24 +/- 5.8 mL min-1 kg-1, without any change on peak VO2 and on cardiac frequency when pressure suit was used. Results were different for paraplegics: peak VO2 was significantly higher (21.5 +/- 6.5 mL min-1 kg-1 without contention and 23.8 +/- 6.3 mL min-1 kg-1 with contention), heart rate was significantly lower at all stages of exercise with antigravity suit and comfort was better during exercise and rest. In our study, contention contributed to increase paraplegics's performances, but responses depend also on spinal cord level, injury age, spasticity. Therefore, testing paraplegics using an antigravity suit may be useful to determine if neurovegetative disturbances significantly modify their cardiac adaptation and capability. If gravity suit is efficient, contention tights might be prescribed, with respect to subject's legs measurements. But, because these tights are very difficult to put on, their efficiency has to be proved before, the motivation of the subject is essential too.

Muscle performance following an acute bout of plyometric training combined with low or high intensity weight exercise.

PubMed

Beneka, Anastasia G; Malliou, Paraskevi K; Missailidou, Victoria; Chatzinikolaou, Athanasios; Fatouros, Ioannis; Gourgoulis, Vassilios; Georgiadis, Elias

2013-01-01

To determine the time course of performance responses after an acute bout of plyometric exercise combined with high and low intensity weight training, a 3-group (including a control group), repeated-measures design was employed. Changes in performance were monitored through jumping ability by measuring countermovement and squat jumping, and strength performance assessment through isometric and isokinetic testing of knee extensors (at two different velocities). Participants in both experimental groups performed a plyometric protocol consisting of 50 jumps over 50 cm hurdles and 50 drop jumps from a 50 cm plyometric box. Additionally, each group performed two basic weight exercises consisting of leg presses and leg extensions at 90-95% of maximum muscle strength for the high intensity group and 60% of maximum muscle strength for the low intensity group. The results of the study suggest that an acute bout of intense plyometric exercise combined with weight exercise induces time-dependent changes in performance, which are also dependent on the nature of exercise protocol and testing procedures. In conclusion, acute plyometric exercise with weight exercise may induce a substantial decline in jumping performance for as long as 72 hours but not in other forms of muscle strength.

The Effects of High Intensity Exercise on Overall Leg Strength of Non-Sickel-Cell-Trait and Sickle-Cell-Trait Individuals.

ERIC Educational Resources Information Center

Williams, Hill, Jr.; Evans, Mel

The purpose of this study was to determine if there was any significant difference in overall leg strength gains in individuals with sickle-cell-trait as compared to non-sickle-cell-trait individuals, as measured by the leg dynamometer. Twenty black male first-year college students were used in this study. The subjects were divided into a control…

Critical load: a novel approach to determining a sustainable intensity during resistance exercise.

PubMed

Arakelian, Vivian M; Mendes, Renata G; Trimer, Renata; Rossi Caruso, Flavia C; de Sousa, Nuno M; Borges, Vanessa C; do Valle Gomes Gatto, Camila; Baldissera, Vilmar; Arena, Ross; Borghi-Silva, Audrey

2017-05-01

A hyperbolic function as well as a linear relationship between power output and time to exhaustion (Tlim) has been consistently observed during dynamic non-resistive exercises. However, little is known about its concept to resistance exercises (RE), which could be defined as critical load (CL). This study aimed to verify the existence of CL during dynamic RE and to verify the number of workbouts necessary to determine the optimal modeling to achieve it. Fifteen healthy men (23±2.5 yrs) completed 1 repetition maximum test (1RM) on a leg press and 3 (60%, 75% and 90% of 1RM) or 4 (+ 30% of 1RM) workbouts protocols to obtain the CL by hyperbolic and linear regression models between Tlim and load performed. Blood lactate and leg fatigue were also measured. CL was obtained during RE and 3 workbouts protocol estimate it at 53% while 4 tests at 38% of 1 RM. However, based on coefficients of determination, 3 protocols provided a better fit than the 4-parameter model, respectively (R2>0.95 vs. >0.77). Moreover, all intensities increased blood lactate and leg fatigue, however, when corrected by Tlim, were significantly lower at CL. It was possible to determinate CL during dynamic lower limbs RE and that 3 exhaustive workbouts can be used to better estimate the CL, constituting a new concept of determining this threshold during dynamic RE and reducing the physically demanding nature of the protocol. These findings may have important applications for functional performance evaluation and prescription of RE programs.

Carotid-cardiac baroreflex response and LBNP tolerance following resistance training

NASA Technical Reports Server (NTRS)

Tatro, D. L.; Dudley, G. A.; Convertino, V. A.

1992-01-01

The purpose of this study was to examine the effect of lower body resistance training on cardiovascular control mechanisms and blood pressure maintenance during an orthostatic challenge. Lower body negative pressure (LBNP) tolerance, carotid-cardiac baroreflex function (using neck chamber pressure), and calf compliance were measured in eight healthy males before and after 19 wk of knee extension and leg press training. Resistance training sessions consisted of four or five sets of 6-12 repetitions of each exercise, performed two times per week. Training increased strength 25 +/- 3 (SE) percent (P = 0.0003) and 31 +/- 6 percent (P = 0.0004), respectively, for the leg press and knee extension exercises. Average fiber size in biopsy samples of m. vastus lateralis increased 21 +/- 5 percent (P = 0.0014). Resistance training had no significant effect on LBNP tolerance. However, calf compliance decreased in five of the seven subjects measured, with the group average changing from 4.4 +/- 0.6 ml.mm Hg-1 to 3.9 +/- 0.3 ml.mm Hg-1 (P = 0.3826). The stimulus-response relationship of the carotid-cardiac baroreflex response shifted to the left on the carotid pressure axis as indicated by a reduction of 6 mm Hg in baseline systolic blood pressure (P = 0.0471). In addition, maximum slope increased from 5.4 +/- 1.3 ms.mm Hg-1 before training to 6.6 +/- 1.6 ms.mm Hg-1 after training (P = 0.0141). Our results suggest the possibility that high resistance, lower extremity exercise training can cause a chronic increase in sensitivity and resetting of the carotid-cardiac baroreflex.

Muscle preservation in long duration space missions: The eccentric factor

NASA Technical Reports Server (NTRS)

Buchanan, Paul; Dudley, Gary A.; Tesch, Per A.; Hather, Bruce M.

1990-01-01

In our quest to understand, and eventually prevent, the loss of muscle strength and mass that occurs during prolonged periods in microgravity, we have organized our research approach by systems and useful terrestrial analogs. Our hypothesis was that: The eccentric movement, or lengthening component, of dynamic, resistive exercise, is required for the production of the greatest gains in strength and muscle hypertrophy in the most metabolically efficient, and time effective manner. The exercises selected were leg presses, leg (knee) extensions, and hamstring curls. In this 30 week study, 38 male subjects, between the ages of 25 and 50, were divided into four groups. One group performed 5 sets of 8-12 repetitions per set of conventional concentric/eccentric (CON/ECC) exercises. Another group performed only the concentric (CON) movement on the same schedule. The third group performed twice the number of sets in the concentric only mode (CON/CON), and the last group served as controls. We interpret these data as convincing evidence that the eccentric component of heavy resistance training is required along with the concentric for the most effective increase in strength and muscle fiber size in the least time. We also conclude that such heavy exercise of any such muscle group need not consume inordinately long periods of time, and is quite satisfactorily effective when performed on 72 hour centers.

Maximal exercise and muscle oxygen extraction in acclimatizing lowlanders and high altitude natives

PubMed Central

Lundby, Carsten; Sander, Mikael; van Hall, Gerrit; Saltin, Bengt; Calbet, José A L

2006-01-01

The tight relation between arterial oxygen content and maximum oxygen uptake () within a given person at sea level is diminished with altitude acclimatization. An explanation often suggested for this mismatch is impairment of the muscle O2 extraction capacity with chronic hypoxia, and is the focus of the present study. We have studied six lowlanders during maximal exercise at sea level (SL) and with acute (AH) exposure to 4100 m altitude, and again after 2 (W2) and 8 weeks (W8) of altitude sojourn, where also eight high altitude native (Nat) Aymaras were studied. Fractional arterial muscle O2 extraction at maximal exercise was 90.0 ± 1.0% in the Danish lowlanders at sea level, and remained close to this value in all situations. In contrast to this, fractional arterial O2 extraction was 83.2 ± 2.8% in the high altitude natives, and did not change with the induction of normoxia. The capillary oxygen conductance of the lower extremity, a measure of oxygen diffusing capacity, was decreased in the Danish lowlanders after 8 weeks of acclimatization, but was still higher than the value obtained from the high altitude natives. The values were (in ml min−1 mmHg−1) 55.2 ± 3.7 (SL), 48.0 ± 1.7 (W2), 37.8 ± 0.4 (W8) and 27.7 ± 1.5 (Nat). However, when correcting oxygen conductance for the observed reduction in maximal leg blood flow with acclimatization the effect diminished. When calculating a hypothetical leg at altitude using either the leg blood flow or the O2 conductance values obtained at sea level, the former values were almost completely restored to sea level values. This would suggest that the major determinant for not to increase with acclimatization is the observed reduction in maximal leg blood flow and O2 conductance. PMID:16581864

Creatine monohydrate supplementation during eight weeks of progressive resistance training increases strength in as little as two weeks without reducing markers of muscle damage.

PubMed

Kaviani, Mojtaba; Abassi, Aboozar; Chilibeck, Philip D

2018-05-02

Creatine supplementation (Cr) increases strength during resistance training, but the time course of this strength increase is unclear. The aim was to determine the precise time course by which Cr could increase strength and whether Cr prevents muscle damage during eight weeks of resistance training. Young males were randomized (double blind) to Cr (n=9, 0.07g/kg/d) and placebo (n=9) during 8-weeks of resistance training (3d/week). Strength was assessed across six exercises every two weeks. Venous blood samples obtained at baseline, and 24 and 48 hours after the final resistance training session were assessed for creatine kinase [CK] and lactate dehydrogenase [LDH] as measures of muscle damage. Strength was significantly higher in the Cr versus placebo group (p<0.05) after two weeks of training for three of the six exercises (bench press, leg press, shoulder press). By the end of the eight weeks of training, strength was significantly higher in the Cr versus placebo group (p<0.05) for four of the six exercises (bench press, leg press, shoulder press, and triceps extension, but not biceps curl or lat-pulldown). Creatine supplementation did not prevent muscle damage. Indeed, muscle damage markers increased in the Cr compared to placebo group (p<0.05). Cr increased muscular strength in as little as two weeks during a resistance training program; however, this was not accompanied by decreased muscle damage. Greater muscle damage with Cr may be due to a greater training intensity enabled by Cr supplementation. This might lead to greater protein turnover and enhanced muscle adaptation.

Inhibition of α-adrenergic tone disturbs the distribution of blood flow in the exercising human limb.

PubMed

Heinonen, Ilkka; Wendelin-Saarenhovi, Maria; Kaskinoro, Kimmo; Knuuti, Juhani; Scheinin, Mika; Kalliokoski, Kari K

2013-07-15

The role of neuronal regulation of human cardiovascular function remains incompletely elucidated, especially during exercise. Here we, by positron emission tomography, monitored tissue-specific blood flow (BF) changes in nine healthy young men during femoral arterial infusions of norepinephrine (NE) and phentolamine. At rest, the α-adrenoceptor agonist NE reduced BF by ~40%, similarly in muscles (from 3.2 ± 1.9 to 1.4 ± 0.3 ml·min(-1)·100 g(-1) in quadriceps femoris muscle), bone (from 1.1 ± 0.4 to 0.5 ± 0.2 ml·min(-1)·100 g(-1)) and adipose tissue (AT) (from 1.2 ± 0.7 to 0.7 ± 0.3 ml·min(-1)·100 g(-1)). During exercise, NE reduced exercising muscle BF by ~16%. BF in AT was reduced similarly as rest. The α-adrenoceptor antagonist phentolamine increased BF similarly in the different muscles and other tissues of the limb at rest. During exercise, BF in inactive muscle was increased 3.4-fold by phentolamine compared with exercise without drug, but BF in exercising muscles was not influenced. Bone and AT (P = 0.055) BF were also increased by phentolamine in the exercise condition. NE increased and phentolamine decreased oxygen extraction in the limb during exercise. We conclude that inhibition of α-adrenergic tone markedly disturbs the distribution of BF and oxygen extraction in the exercising human limb by increasing BF especially around inactive muscle fibers. Moreover, although marked functional sympatholysis also occurs during exercise, the arterial NE infusion that mimics the exaggerated sympathetic nerve activity commonly seen in patients with cardiovascular disease was still capable of directly limiting BF in the exercising leg muscles.

Resistance exercise-induced increases in putative anabolic hormones do not enhance muscle protein synthesis or intracellular signalling in young men.

PubMed

West, Daniel W D; Kujbida, Gregory W; Moore, Daniel R; Atherton, Philip; Burd, Nicholas A; Padzik, Jan P; De Lisio, Michael; Tang, Jason E; Parise, Gianni; Rennie, Michael J; Baker, Steven K; Phillips, Stuart M

2009-11-01

We aimed to determine whether exercise-induced elevations in systemic concentration of testosterone, growth hormone (GH) and insulin-like growth factor-1 (IGF-1) enhanced post-exercise myofibrillar protein synthesis (MPS) and phosphorylation of signalling proteins important in regulating mRNA translation. Eight young men (20 +/- 1.1 years, BMI = 26 +/- 3.5 kg m(-2)) completed two exercise protocols designed to maintain basal hormone concentrations (low hormone, LH) or elicit increases in endogenous hormones (high hormone, HH). In the LH protocol, participants performed a bout of unilateral resistance exercise with the elbow flexors. The HH protocol consisted of the same elbow flexor exercise with the contralateral arm followed immediately by high-volume leg resistance exercise. Participants consumed 25 g of protein after arm exercise to maximize MPS. Muscle biopsies and blood samples were taken as appropriate. There were no changes in serum testosterone, GH or IGF-1 after the LH protocol, whereas there were marked elevations after HH (testosterone, P < 0.001; GH, P < 0.001; IGF-1, P < 0.05). Exercise stimulated a rise in MPS in the biceps brachii (rest = 0.040 +/- 0.007, LH = 0.071 +/- 0.008, HH = 0.064 +/- 0.014% h(-1); P < 0.05) with no effect of elevated hormones (P = 0.72). Phosphorylation of the 70 kDa S6 protein kinase (p70S6K) also increased post-exercise (P < 0.05) with no differences between conditions. We conclude that the transient increases in endogenous purportedly anabolic hormones do not enhance fed-state anabolic signalling or MPS following resistance exercise. Local mechanisms are likely to be of predominant importance for the post-exercise increase in MPS.

Effect of Exercise-Induced Enhancement of the Leg-Extensor Muscle-Tendon Unit Capacities on Ambulatory Mechanics and Knee Osteoarthritis Markers in the Elderly

PubMed Central

Karamanidis, Kiros; Oberländer, Kai Daniel; Niehoff, Anja; Epro, Gaspar; Brüggemann, Gert-Peter

2014-01-01

Objective Leg-extensor muscle weakness could be a key component in knee joint degeneration in the elderly because it may result in altered muscular control during locomotion influencing the mechanical environment within the joint. This work aimed to examine whether an exercise-induced enhancement of the triceps surae (TS) and quadriceps femoris (QF) muscle-tendon unit (MTU) capacities would affect mechanical and biological markers for knee osteoarthritis in the elderly. Methods Twelve older women completed a 14-week TS and QF MTU exercise intervention, which had already been established as increasing muscle strength and tendon stiffness. Locomotion mechanics and serum cartilage oligomeric matrix protein (COMP) levels were examined during incline walking. MTU mechanical properties were assessed using simultaneously ultrasonography and dynamometry. Results Post exercise intervention, the elderly had higher TS and QF contractile strength and tendon-aponeurosis stiffness. Regarding the incline gait task, the subjects demonstrated a lower external knee adduction moment and lower knee adduction angular impulse during the stance phase post-intervention. Furthermore, post-intervention compared to pre-intervention, the elderly showed lower external hip adduction moment, but revealed higher plantarflexion pushoff moment. The changes in the external knee adduction moment were significantly correlated with the improvement in ankle pushoff function. Serum COMP concentration increased in response to the 0.5-h incline walking exercise with no differences in the magnitude of increment between pre- and post-intervention. Conclusions This work emphasizes the important role played by the ankle pushoff function in knee joint mechanical loading during locomotion, and may justify the inclusion of the TS MTU in prevention programs aiming to positively influence specific mechanical markers for knee osteoarthritis in the elderly. However, the study was unable to show that COMP is amenable to change in the elderly following a 14-week exercise intervention and, therefore, the physiological benefit of improved muscle function for knee cartilage requires further investigation. PMID:24905024

Effect of exercise-induced enhancement of the leg-extensor muscle-tendon unit capacities on ambulatory mechanics and knee osteoarthritis markers in the elderly.

PubMed

Karamanidis, Kiros; Oberländer, Kai Daniel; Niehoff, Anja; Epro, Gaspar; Brüggemann, Gert-Peter

2014-01-01

Leg-extensor muscle weakness could be a key component in knee joint degeneration in the elderly because it may result in altered muscular control during locomotion influencing the mechanical environment within the joint. This work aimed to examine whether an exercise-induced enhancement of the triceps surae (TS) and quadriceps femoris (QF) muscle-tendon unit (MTU) capacities would affect mechanical and biological markers for knee osteoarthritis in the elderly. Twelve older women completed a 14-week TS and QF MTU exercise intervention, which had already been established as increasing muscle strength and tendon stiffness. Locomotion mechanics and serum cartilage oligomeric matrix protein (COMP) levels were examined during incline walking. MTU mechanical properties were assessed using simultaneously ultrasonography and dynamometry. Post exercise intervention, the elderly had higher TS and QF contractile strength and tendon-aponeurosis stiffness. Regarding the incline gait task, the subjects demonstrated a lower external knee adduction moment and lower knee adduction angular impulse during the stance phase post-intervention. Furthermore, post-intervention compared to pre-intervention, the elderly showed lower external hip adduction moment, but revealed higher plantarflexion pushoff moment. The changes in the external knee adduction moment were significantly correlated with the improvement in ankle pushoff function. Serum COMP concentration increased in response to the 0.5-h incline walking exercise with no differences in the magnitude of increment between pre- and post-intervention. This work emphasizes the important role played by the ankle pushoff function in knee joint mechanical loading during locomotion, and may justify the inclusion of the TS MTU in prevention programs aiming to positively influence specific mechanical markers for knee osteoarthritis in the elderly. However, the study was unable to show that COMP is amenable to change in the elderly following a 14-week exercise intervention and, therefore, the physiological benefit of improved muscle function for knee cartilage requires further investigation.

Effects of whole body vibration on bone mineral density and falls: results of the randomized controlled ELVIS study with postmenopausal women.

PubMed

von Stengel, S; Kemmler, W; Engelke, K; Kalender, W A

2011-01-01

We determined whether the effect of exercise on bone mineral density (BMD) and falls can be enhanced by whole body vibration (WBV). In summary, the multi-purpose exercise training was effective to increase lumbar BMD but added WBV did not enhance this effect. However, falls were lowest in the exercise program combined with WBV. WBV is a new approach to reduce the risk of osteoporotic fractures. In the "Erlangen Longitudinal Vibration Study" (ELVIS), we investigated whether WBV enhances the effect of multifunctional exercise on BMD and falls. One hundred fifty-one postmenopausal women (68.5 ± 3.1 years) were randomly assigned to a: (1) conventional training group (TG); (2) conventional training group including vibration (TGV); and (3) wellness control group (CG). TG conducted an exercise program consisting of 20 min dancing aerobics, 5 min balance training, 20 min functional gymnastics, and 15 min dynamic leg-strength training on vibration plates (without vibration) twice a week. TGV performed an identical exercise regimen with vibration (25-35 Hz) during the leg-strengthening sequence. CG performed a low-intensity wellness program. BMD was measured at the hip and lumbar spine at baseline and follow-up using the DXA method. Falls were recorded daily via the calendar method. After 18 months, an increase in BMD at the lumbar spine was observed in both training groups (TGV: +1.5% vs. TG: +2.1%). The difference between the TG and the CG (1.7%) was significant. At the hip no changes were determined in either group. The fall frequency was significantly lower in TGV (0.7 falls/person) compared with CG (1.5), whereas the difference between TG (0.96) and CG was not significant. A multifunctional training program had a positive impact on lumbar BMD. The application of vibration did not enhance these effects. However, only the training including WBV affected the number of falls significantly.

Differential Responses of Post-Exercise Recovery of Leg Blood Flow and Oxygen Uptake Kinetics in HFpEF versus HFrEF.

PubMed

Thompson, Richard B; Pagano, Joseph J; Mathewson, Kory W; Paterson, Ian; Dyck, Jason R; Kitzman, Dalane W; Haykowsky, Mark J

2016-01-01

The goals of the current study were to compare leg blood flow, oxygen extraction and oxygen uptake (VO2) after constant load sub-maximal unilateral knee extension (ULKE) exercise in patients with heart failure with reduced ejection fraction (HFrEF) compared to those with preserved ejection fraction (HFpEF). Previously, it has been shown that prolonged whole body VO2 recovery kinetics are directly related to disease severity and all-cause mortality in HFrEF patients. To date, no study has simultaneously measured muscle-specific blood flow and oxygen extraction post exercise recovery kinetics in HFrEF or HFpEF patients; therefore it is unknown if muscle VO2 recovery kinetics, and more specifically, the recovery kinetics of blood flow and oxygen extraction at the level of the muscle, differ between HF phenotypes. Ten older (68±10yrs) HFrEF (n = 5) and HFpEF (n = 5) patients performed sub-maximal (85% of maximal weight lifted during an incremental test) ULKE exercise for 4 minutes. Femoral venous blood flow and venous O2 saturation were measured continuously from the onset of end-exercise, using a novel MRI method, to determine off-kinetics (mean response times, MRT) for leg VO2 and its determinants. HFpEF and HFrEF patients had similar end-exercise leg blood flow (1.1±0.6 vs. 1.2±0.6 L/min, p>0.05), venous saturation (42±12 vs. 41±11%, p>0.05) and VO2 (0.13±0.08 vs. 0.11±0.05 L/min, p>0.05); however HFrEF had significantly delayed recovery MRT for flow (292±135sec. vs 105±63sec., p = 0.004) and VO2 (95±37sec. vs. 47±15sec., p = 0.005) compared to HFpEF. Impaired muscle VO2 recovery kinetics following ULKE exercise differentiated HFrEF from HFpEF patients and suggests distinct underlying pathology and potential therapeutic approaches in these populations.

Effect of isokinetic training on strength, functionality and proprioception in athletes with functional ankle instability.

PubMed

Sekir, Ufuk; Yildiz, Yavuz; Hazneci, Bulent; Ors, Fatih; Aydin, Taner

2007-05-01

The purpose of this study was to investigate the effects of isokinetic exercise on strength, joint position sense and functionality in recreational athletes with functional ankle instability (FAI). Strength, proprioception and balance of 24 recreational athletes with unilateral FAI were evaluated by using isokinetic muscle strength measurement, ankle joint position sense and one leg standing test. The functional ability was evaluated using five different tests. These were; single limb hopping course (SLHC), one legged and triple legged hop for distance (OLHD-TLHD), and six and cross six meter hop for time (SMHT-CSMHT). Isokinetic peak torque of the ankle invertor and evertor muscles were assessed eccentrically and concentrically at test speeds of 120 degrees /s. Isokinetic exercise protocol was carried out at an angular velocity of 120 degrees /s. The exercise session was repeated three times a week and lasted after 6 weeks. At baseline, concentric invertor strength was found to be significantly lower in the functionally unstable ankles compared to the opposite healthy ankles (p < 0.001). This difference was not present after executing the 6 weeks exercise sessions (p > 0.05). Ankle joint position sense in the injured ankles declined significantly from 2.35 +/- 1.16 to 1.33 +/- 0.62 degrees for 10 degrees of inversion angle (p < 0.001) and from 3.10 +/- 2.16 to 2.19 +/- 0.98 degrees for 20 degrees of inversion angle (p < 0.05) following the isokinetic exercise. One leg standing test score decreased significantly from 15.17 +/- 8.50 to 11.79 +/- 7.81 in the injured ankles (p < 0.001). Following the isokinetic exercise protocol, all of the worsened functional test scores in the injured ankles as compared to the opposite healthy ankles displayed a significant improvement (p < 0.01 for OLHD and CSMHT, p < 0.001 for SLHC, TLHD, and SMHT). These results substantiate the deficits of strength, proprioception, balance and functionality in recreational athletes with FAI. The isokinetic exercise program used in this study had a positive effect on these parameters.

Endothelial mechanotransduction proteins and vascular function are altered by dietary sucrose supplementation in healthy young male subjects.

PubMed

Gliemann, Lasse; Rytter, Nicolai; Lindskrog, Mads; Slingsby, Martina H Lundberg; Åkerström, Thorbjörn; Sylow, Lykke; Richter, Erik A; Hellsten, Ylva

2017-08-15

Mechanotransduction in endothelial cells is a central mechanism in the regulation of vascular tone and vascular remodelling Mechanotransduction and vascular function may be affected by high sugar levels in plasma because of a resulting increase in oxidative stress and increased levels of advanced glycation end-products (AGE). In healthy young subjects, 2 weeks of daily supplementation with 3 × 75 g of sucrose was found to reduce blood flow in response to passive lower leg movement and in response to 12 W of knee extensor exercise. This vascular impairment was paralleled by up-regulation of platelet endothelial cell adhesion molecule (PECAM)-1, endothelial nitric oxide synthase, NADPH oxidase and Rho family GTPase Rac1 protein expression, an increased basal phosphorylation status of vascular endothelial growth factor receptor 2 and a reduced phosphorylation status of PECAM-1. There were no measurable changes in AGE levels. The findings of the present study demonstrate that daily high sucrose intake markedly affects mechanotransduction proteins and has a detrimental effect on vascular function. Endothelial mechanotransduction is important for vascular function but alterations and activation of vascular mechanosensory proteins have not been investigated in humans. In endothelial cell culture, simple sugars effectively impair mechanosensor proteins. To study mechanosensor- and vascular function in humans, 12 young healthy male subjects supplemented their diet with 3 × 75 g sucrose day -1 for 14 days in a randomized cross-over design. Before and after the intervention period, the hyperaemic response to passive lower leg movement and active knee extensor exercise was determined by ultrasound doppler. A muscle biopsy was obtained from the thigh muscle before and after acute passive leg movement to allow assessment of protein amounts and the phosphorylation status of mechanosensory proteins and NADPH oxidase. The sucrose intervention led to a reduced flow response to passive movement (by 17 ± 2%) and to 12 W of active exercise (by 9 ± 1%), indicating impaired vascular function. A reduced flow response to passive and active exercise was paralleled by a significant up-regulation of platelet endothelial cell adhesion molecule (PECAM-1), endothelial nitric oxide synthase, NADPH oxidase and the Rho family GTPase Rac1 protein expression in the muscle tissue, as well as an increased basal phosphorylation status of vascular endothelial growth factor receptor 2 and a reduced phosphorylation status of PECAM-1. The phosphorylation status was not acutely altered with passive leg movement. These findings indicate that a regular intake of high levels of sucrose can impair vascular mechanotransduction and increase the oxidative stress potential, and suggest that dietary excessive sugar intake may contribute to the development of vascular disease. © 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.

Muscle power is an important measure to detect deficits in muscle function in hip osteoarthritis: a cross-sectional study.

PubMed

Bieler, Theresa; Magnusson, Stig Peter; Christensen, Helle Elisabeth; Kjaer, Michael; Beyer, Nina

2017-07-01

To investigate between-leg differences in hip and thigh muscle strength and leg extensor power in patients with unilateral hip osteoarthritis. Further, to compare between-leg differences in knee extensor strength and leg extensor power between patients and healthy peers. Seventy-two patients (60-87 years) with radiographic and symptomatic hip osteoarthritis not awaiting hip replacement and 35 healthy peers (63-82 years) were included. Hip and thigh muscle strength and leg extensor power were measured in patients and knee extensor strength and leg extensor power in healthy. The symptomatic extremity in patients was significantly (p < 0.05, paired t-test) weaker compared with the non-symptomatic extremity for five hip muscles (8-17%), knee extensors (11%) and leg extensor power (19%). Healthy older adults had asymmetry in knee extensor strength (6%, p < 0.05) comparable to that found in patients, but had no asymmetry in leg extensor power. Patients had generalized weakening of the affected lower extremity and numerically the largest asymmetry was evident for leg extensor power. In contrast, healthy peers had no asymmetry in leg extensor power. These results indicate that exercise interventions focusing on improving leg extensor power of the symptomatic lower extremity and reducing asymmetry may be beneficial for patients with hip osteoarthritis. Implications for Rehabilitation Even in patients with mild symptoms not awaiting hip replacement a generalized muscle weakening of the symptomatic lower extremity seems to be present. Between-leg differences in leg extensor power (force × velocity) appears to be relatively large (19%) in patients with unilateral hip osteoarthritis in contrast to healthy peers who show no asymmetry. Compared to muscle strength the relationship between functional performance and leg extensor power seems to be stronger, and more strongly related to power of the symptomatic lower extremity. Our results indicate that exercise interventions focusing on improving leg extensor power of the symptomatic lower extremity and reducing asymmetry may be beneficial for patients with mild symptoms not awaiting hip replacement.

Femoral Blood Flow and Cardiac Output During Blood Flow Restricted Leg Press Exercise

NASA Technical Reports Server (NTRS)

Everett, M. E.; Hackney, K.; Ploutz-Snyder, L.

2011-01-01

Low load blood flow restricted resistance exercise (LBFR) causes muscle hypertrophy that may be stimulated by the local ischemic environment created by the cuff pressure. However, local blood flow (BF) during such exercise is not well understood. PURPOSE: To characterize femoral artery BF and cardiac output (CO) during leg press exercise (LP) performed at a high load (HL) and low load (LL) with different levels of cuff pressure. METHODS: Eleven subjects (men/women 4/7, age 31.4+/-12.8 y, weight 68.9+/-13.2 kg, mean+/-SD) performed 3 sets of supine left LP to fatigue with 90 s of rest in 4 conditions: HL (%1-RM/cuff pressure: 80%/0); LL (20%/0); LBFR(sub DBP) (20%/1.3 x diastolic blood pressure, BP); LBFR(sub SBP) (20%/1.3 x supine systolic BP). The cuff remained inflated throughout the LBFR exercise sessions. Artery diameter, velocity time integral (VTI), and stroke volume (SV) were measured using Doppler ultrasound at rest and immediately after each set of exercise. Heart rate (HR) was monitored using a 3-lead ECG. BF was calculated as VTI x vessel cross-sectional area. CO was calculated as HR x SV. The data obtained after each set of exercise were averaged and used for analyses. Multi-level modeling was used to determine the effect of exercise condition on dependent variables. Statistical significance was set a priori at p< 0.05. RESULTS: Artery diameter did not change from baseline. BF increased (p<0.05) after exercise in each condition except LBFR(sub SBP) in the order of HL (12.73+/-1.42 cm3,mean+/-SE) > LL (9.92+/-0.82 cm3) > LBFR(sub dBP)(6.47+/-0.79 cm3) > LBFR(sub SBP) (3.51+/-0.59 cm3). Blunted exercise induced increases occurred in HR, SV, and CO after LBFR compared to HL and LL. HR increased 45% after HL and LL and 28% after LBFR (p<0.05), but SV increased (p<0.05) only after HL. Consequently, the increase (p<0.05) in CO was greater in HL and LL (approximately 3 L/min) than in LBFR (approximately 1 L/min). CONCLUSION: BF during LBFR(sub SBP) was 1/3 of that observed in LL, which supports the hypothesis that local ischemia stimulates the LBFR hypertrophic response. As the cuff did not compress the artery, the ischemia may have occurred because of the blunted rise in CO or because arterial BP cannot overcome the cuff pressure. As LBFR(sub DBP) effectively reduced BF and CO with cuff pressures less than systolic BP, future studies should investigate the hypertrophic potential of LBFR at even lower cuff pressures.

Exercise for Well or Community Living Older Adults.

ERIC Educational Resources Information Center

Bennett, John P.

This set of instructions is designed for use by instructors in aerobic dance, although the instructions can also be used by individuals for an exercise program. Descriptions are given of specific exercises for the head and neck, shoulders, arms, legs, and chest and trunk. Routines for a complete aerobic dance session (warm-up, aerobic, and…

Effects of 14 days of head-down tilt bed rest on cutaneous vasoconstrictor responses in humans

NASA Technical Reports Server (NTRS)

Wilson, Thad E.; Shibasaki, Manabu; Cui, Jian; Levine, Benjamin D.; Crandall, Craig G.

2003-01-01

This study tested the hypothesis that head-down tilt bed rest (HDBR) reduces adrenergic and nonadrenergic cutaneous vasoconstrictor responsiveness. Additionally, an exercise countermeasure group was included to identify whether exercise during bed rest might counteract any vasoconstrictor deficits that arose during HDBR. Twenty-two subjects underwent 14 days of strict 6 degrees HDBR. Eight of these 22 subjects did not exercise during HDBR, while 14 of these subjects exercised on a supine cycle ergometer for 90 min a day at 75% of pre-bed rest heart rate maximum. To assess alpha-adrenergic vasoconstrictor responsiveness, intradermal microdialysis was used to locally administer norepinephrine (NE), while forearm skin blood flow (SkBF; laser-Doppler flowmetry) was monitored over microdialysis membranes. Nonlinear regression modeling was used to identify the effective drug concentration that caused 50% of the cutaneous vasoconstrictor response (EC(50)) and minimum values from the SkBF-NE dose-response curves. In addition, the effects of HDBR on nonadrenergic cutaneous vasoconstriction were assessed via the venoarteriolar response of the forearm and leg. HDBR did not alter EC(50) or the magnitude of cutaneous vasoconstriction to exogenous NE administration regardless of whether the subjects exercised during HDBR. Moreover, HDBR did not alter the forearm venoarteriolar response in either the control or exercise groups during HDBR. However, HDBR significantly reduced the magnitude of cutaneous vasoconstriction due to the venoarteriolar response in the leg, and this response was similarly reduced in the exercise group. These data suggest that HDBR does not alter cutaneous vasoconstrictor responses to exogenous NE administration, whereas cutaneous vasoconstriction of the leg due to the venoarteriolar response is reduced after HDBR. It remains unclear whether attenuated venoarteriolar responses in the lower limbs contribute to reduced orthostatic tolerance after bed rest and spaceflight.

Effects of Dao De Xin Xi Exercise on Balance and Quality of Life in Thai Elderly Women

PubMed Central

Intarakamhang, Patrawut; Chintanaprawasee, Pantipa

2012-01-01

The objective of this study was to evaluate the effects of a 12-week Dao De Xin Xi exercise, modified short forms of Tai Chi, on balance and quality of life in Thai elderly population. Quasi-Experimental research, pretest-posttest one group design was done at Physical Medicine and Rehabilitation Department, Phramongkutklao Hospital. Thai healthy elderly women over the age of 60, requiring regular Dao De Xin Xi exercise were recruited from either patients or workers in the hospital. A 60-minute Dao De Xin Xi exercise class was set as 3 times per week for 12 weeks. At baseline and 12 weeks, participants were tested in their static balance (Single-Leg Stance Timed Test with eyes open and close), dynamic balance (Expanded Timed Up and Go (ETUG) Test). Quality of life was measured by the abbreviated Thai version of the World Health Organization Quality of Life (WHOQOL-BREF) questionnaire. Fourteen females were studied with mean age of 62.8±4.3 years old. The Single-Leg Stance Timed Test with eyes open and close, Expanded Timed Up and Go (ETUG) Test improved significantly (before versus after exercises p <0.001). Significant improvement in quality of life were also found in each 4 domains, including physical health, psychological, social relationship, and environment (before versus after exercises p =0.001, 0.001, 0.004 and 0.005 respectively). No significant improvement was found only in the right Single-Leg Stance Timed Test with eyes close (p =0.091). A three times per week for 12-week Dao De Xin Xi exercise may help Thai elderly women improve both static, dynamic balance and quality of life. PMID:22980114

Effects of Dao De Xin Xi exercise on balance and quality of life in Thai elderly women.

PubMed

Intarakamhang, Patrawut; Chintanaprawasee, Pantipa

2011-12-29

The objective of this study was to evaluate the effects of a 12-week Dao De Xin Xi exercise, modified short forms of Tai Chi, on balance and quality of life in Thai elderly population. Quasi-Experimental research, pretest-posttest one group design was done at Physical Medicine and Rehabilitation Department, Phramongkutklao Hospital. Thai healthy elderly women over the age of 60, requiring regular Dao De Xin Xi exercise were recruited from either patients or workers in the hospital. A 60-minute Dao De Xin Xi exercise class was set as 3 times per week for 12 weeks. At baseline and 12 weeks, participants were tested in their static balance (Single-Leg Stance Timed Test with eyes open and close), dynamic balance (Expanded Timed Up and Go (ETUG) Test). Quality of life was measured by the abbreviated Thai version of the World Health Organization Quality of Life (WHOQOL-BREF) questionnaire. Fourteen females were studied with mean age of 62.8±4.3 years old. The Single-Leg Stance Timed Test with eyes open and close, Expanded Timed Up and Go (ETUG) Test improved significantly (before versus after exercises p <0.001). Significant improvement in quality of life were also found in each 4 domains, including physical health, psychological, social relationship, and environment (before versus after exercises p =0.001, 0.001, 0.004 and 0.005 respectively). No significant improvement was found only in the right Single-Leg Stance Timed Test with eyes close (p =0.091). A three times per week for 12-week Dao De Xin Xi exercise may help Thai elderly women improve both static, dynamic balance and quality of life.

Increasing blood flow to exercising muscle attenuates systemic cardiovascular responses during dynamic exercise in humans.

PubMed

Ichinose, Masashi; Ichinose-Kuwahara, Tomoko; Kondo, Narihiko; Nishiyasu, Takeshi

2015-11-15

Reducing blood flow to working muscles during dynamic exercise causes metabolites to accumulate within the active muscles and evokes systemic pressor responses. Whether a similar cardiovascular response is elicited with normal blood flow to exercising muscles during dynamic exercise remains unknown, however. To address that issue, we tested whether cardiovascular responses are affected by increases in blood flow to active muscles. Thirteen healthy subjects performed dynamic plantarflexion exercise for 12 min at 20%, 40%, and 60% of peak workload (EX20, EX40, and EX60) with their lower thigh enclosed in a negative pressure box. Under control conditions, the box pressure was the same as the ambient air pressure. Under negative pressure conditions, beginning 3 min after the start of the exercise, the box pressure was decreased by 20, 45, and then 70 mmHg in stepwise fashion with 3-min step durations. During EX20, the negative pressure had no effect on blood flow or the cardiovascular responses measured. However, application of negative pressure increased blood flow to the exercising leg during EX40 and EX60. This increase in blood flow had no significant effect on systemic cardiovascular responses during EX40, but it markedly attenuated the pressor responses otherwise seen during EX60. These results demonstrate that during mild exercise, normal blood flow to exercising muscle is not a factor eliciting cardiovascular responses, whereas it elicits an important pressor effect during moderate exercise. This suggests blood flow to exercising muscle is a major determinant of cardiovascular responses during dynamic exercise at higher than moderate intensity. Copyright © 2015 the American Physiological Society.

Examining the feasibility of a Microsoft Kinect ™ based game intervention for individuals with anterior cruciate ligament injury risk.

PubMed

Zhiyu Huo; Griffin, Joseph; Babiuch, Ryan; Gray, Aaron; Willis, Bradley; Marjorie, Skubic; Shining Sun

2015-01-01

We describe a feasibility study in which the Microsoft Kinect is used for a game-based exercise to strengthen posterior chain muscles which are often weak in those at high risk of anterior cruciate ligament (ACL) injury. In the game, subjects perform a single posterior chain strengthening exercise. The game uses a side-scrolling video display driven by a hip abduction exercise while a player lies down on the floor. Leg lifts beyond a predetermined angle trigger the jumping action of an animated tiger. We describe the scene and game control, which uses depth images from the Kinect. Although Kinect-based skeletal data are used for many games, the skeletal model does not yield good estimates for positions on the floor. Our proposed system uses multiple leg angle estimators for different angle regions to recognize the player lying down and capture the angle between two legs. We conducted an experiment that validates our system with marker-based Vicon ground truth data. We also present results of an end-to-end test using the game, showing feasibility.

Post-exercise protein synthesis rates are only marginally higher in type I compared with type II muscle fibres following resistance-type exercise.

PubMed

Koopman, René; Gleeson, Benjamin G; Gijsen, Annemie P; Groen, Bart; Senden, Joan M G; Rennie, Michael J; van Loon, Luc J C

2011-08-01

We examined the effect of an acute bout of resistance exercise on fractional muscle protein synthesis rates in human type I and type II muscle fibres. After a standardised breakfast (31 ± 1 kJ kg(-1) body weight, consisting of 52 Energy% (En%) carbohydrate, 34 En% protein and 14 En% fat), 9 untrained men completed a lower-limb resistance exercise bout (8 sets of 10 repetitions leg press and leg extension at 70% 1RM). A primed, continuous infusion of L: -[ring-(13)C(6)]phenylalanine was combined with muscle biopsies collected from both legs immediately after exercise and after 6 h of post-exercise recovery. Single muscle fibres were dissected from freeze-dried biopsies and stained for ATPase activity with pre-incubation at a pH of 4.3. Type I and II fibres were separated under a light microscope and analysed for protein-bound L: -[ring-(13)C(6)]phenylalanine labelling. Baseline (post-exercise) L: -[ring-(13)C(6)]phenylalanine muscle tissue labelling, expressed as (∂(13)C/(12)C), averaged -32.09 ± 0.28, -32.53 ± 0.10 and -32.02 ± 0.16 in the type I and II muscle fibres and mixed muscle, respectively (P = 0.14). During post-exercise recovery, muscle protein synthesis rates were marginally (8 ± 2%) higher in the type I than type II muscle fibres, at 0.100 ± 0.005 versus 0.094 ± 0.005%/h, respectively (P < 0.05), whereby rates of mixed muscle protein were 0.091 ± 0.005%/h. Muscle protein synthesis rates following resistance-type exercise are only marginally higher in type I compared with type II muscle fibres.

Protein synthesis rates in atrophied gastrocnemius muscles after limb immobilization

NASA Technical Reports Server (NTRS)

Tucker, K. R.; Seider, M. J.; Booth, F. W.

1981-01-01

Noting that protein synthesis declines in the gastrocnemius 6 hr after immobilization, the study sought to detect an increase of protein synthesis when the limb was freed, and to examine the effects of exercise on the rate of increase. Rats were used as subjects, with their hind legs in plaster of Paris in plantar flexion to eliminate strain on the gastrocnemius. Periods of immobilization were varied and samples of blood from the muscle were taken to track protein synthesis rates for different groups in immobilization and exercise regimens (running and weightlifting). Synthesis rates declined 3.6% during time in the cast, then increased 6.3%/day after the casts were removed. Both running and weightlifting were found to increase the fractional rate of protein formation in the gastrocnemius muscle when compared with contralateral muscles that were not exercised and were used as controls, suggesting that the mechanism controlling protein synthesis in skeletal muscles is rapidly responsive to changes in muscular contractile activity.

Dissociation of muscle sympathetic nerve activity and leg vascular resistance in humans

NASA Technical Reports Server (NTRS)

Shoemaker, J. K.; Herr, M. D.; Sinoway, L. I.

2000-01-01

We examined the hypothesis that the increase in inactive leg vascular resistance during forearm metaboreflex activation is dissociated from muscle sympathetic nerve activity (MSNA). MSNA (microneurography), femoral artery mean blood velocity (FAMBV, Doppler), mean arterial pressure (MAP), and heart rate (HR) were assessed during fatiguing static handgrip exercise (SHG, 2 min) followed by posthandgrip ischemia (PHI, 2 min). Whereas both MAP and MSNA increase during SHG, the transition from SHG to PHI is characterized by a transient reduction in MAP but sustained elevation in MSNA, facilitating separation of these factors in vivo. Femoral artery vascular resistance (FAVR) was calculated (MAP/MBV). MSNA increased by 59 +/- 20% above baseline during SHG (P < 0.05) and was 58 +/- 18 and 78 +/- 18% above baseline at 10 and 20 s of PHI, respectively (P < 0.05 vs. baseline). Compared with baseline, FAVR increased 51 +/- 22% during SHG (P < 0.0001) but returned to baseline levels during the first 30 s of PHI, reflecting the changes in MAP (P < 0.005) and not MSNA. It was concluded that control of leg muscle vascular resistance is sensitive to changes in arterial pressure and can be dissociated from sympathetic factors.

Ventilatory and circulatory responses at the onset of exercise in man following heart or heart-lung transplantation.

PubMed Central

Banner, N; Guz, A; Heaton, R; Innes, J A; Murphy, K; Yacoub, M

1988-01-01

1. Ventilatory and cardiovascular responses to the onset of voluntary and electrically induced leg exercise were studied in six patients following heart transplantation and five following heart-lung transplantation; the results were compared between the patient groups and also with responses from a group of normal subjects. 2. Oxygen consumption, carbon dioxide production and ventilation and its components were measured over two 30 s periods prior to, and two 30 s periods following, the onset of exercise. Relative changes in stroke volume and cardiac output were derived from ensemble-averaged Doppler measurements of ascending aortic blood velocity over the same 30 s periods. 3. None of the groups of subjects showed any significant differences in responses to voluntary exercise compared to electrically induced exercise of similar work pattern and intensity. 4. Compared to normal controls, the transplanted subjects showed higher resting heart rates which did not increase at the onset of exercise; stroke volume increased, but less than in the normal subjects. The resulting cardiac output increases in the transplanted subjects were minimal compared to the normal subjects. 5. Ventilation and oxygen uptake increased immediately and with similar magnitude in all three groups. 6. These results show that in the same individual it is possible to have an appropriate ventilatory response to the onset of exercise in the presumed absence of a normal corticospinal input to the exercising muscles (electrically induced exercise) and afferent neural information from the lungs and heart, and in the absence of a normal circulatory response to exercise. The mechanisms underlying this ventilatory response remain undetermined. PMID:3136247

Heart Rate Recovery after Submaximal Exercise in Four Different Recovery Protocols in Male Athletes and Non-Athletes

PubMed Central

Barak, Otto F.; Ovcin, Zoran B.; Jakovljevic, Djordje G.; Lozanov-Crvenkovic, Zagorka; Brodie, David A.; Grujic, Nikola G.

2011-01-01

The effects of different recovery protocols on heart rate recovery (HRR) trend through fitted heart rate (HR) decay curves were assessed. Twenty one trained male athletes and 19 sedentary male students performed a submaximal cycle exercise test on four occasions followed by 5 min: 1) inactive recovery in the upright seated position, 2) active (cycling) recovery in the upright seated position, 3) supine position, and 4) supine position with elevated legs. The HRR was assessed as the difference between the peak exercise HR and the HR recorded following 60 seconds of recovery (HRR60). Additionally the time constant decay was obtained by fitting the 5 minute post-exercise HRR into a first-order exponential curve. Within- subject differences of HRR60 for all recovery protocols in both groups were significant (p < 0. 001) except for the two supine positions (p > 0.05). Values of HRR60 were larger in the group of athletes for all conditions (p < 0.001). The time constant of HR decay showed within-subject differences for all recovery conditions in both groups (p < 0.01) except for the two supine positions (p > 0.05). Between group difference was found for active recovery in the seated position and the supine position with elevated legs (p < 0.05). We conclude that the supine position with or without elevated legs accelerated HRR compared with the two seated positions. Active recovery in the seated upright position was associated with slower HRR compared with inactive recovery in the same position. The HRR in athletes was accelerated in the supine position with elevated legs and with active recovery in the seated position compared with non-athletes. Key points In order to return to a pre-exercise value following exercise, heart rate (HR) is mediated by changes in the autonomic nervous system but the underlying mechanisms governing these changes are not well understood. Even though HRR is slower with active recovery, lactate elimination after high intensity exercise might be more important for athletes than the de-cline of heart rate. Lying supine during recovery after exercise may be an effective means of transiently restoring HR and vagal modulation and a safe position for prevention of syncope. PMID:24149885

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

Aging Reduces the Activation of the mTORC1 Pathway after Resistance Exercise and Protein Intake in Human Skeletal Muscle: Potential Role of REDD1 and Impaired Anabolic Sensitivity.

PubMed

Francaux, Marc; Demeulder, Bénédicte; Naslain, Damien; Fortin, Raphael; Lutz, Olivier; Caty, Gilles; Deldicque, Louise

2016-01-15

This study was designed to better understand the molecular mechanisms involved in the anabolic resistance observed in elderly people. Nine young (22 ± 0.1 years) and 10 older (69 ± 1.7 years) volunteers performed a one-leg extension exercise consisting of 10 × 10 repetitions at 70% of their 3-RM, immediately after which they ingested 30 g of whey protein. Muscle biopsies were taken from the vastus lateralis at rest in the fasted state and 30 min after protein ingestion in the non-exercised (Pro) and exercised (Pro+ex) legs. Plasma insulin levels were determined at the same time points. No age difference was measured in fasting insulin levels but the older subjects had a 50% higher concentration than the young subjects in the fed state (p < 0.05). While no difference was observed in the fasted state, in response to exercise and protein ingestion, the phosphorylation state of PKB (p < 0.05 in Pro and Pro+ex) and S6K1 (p = 0.059 in Pro; p = 0.066 in Pro+ex) was lower in the older subjects compared with the young subjects. After Pro+ex, REDD1 expression tended to be higher (p = 0.087) in the older group while AMPK phosphorylation was not modified by any condition. In conclusion, we show that the activation of the mTORC1 pathway is reduced in skeletal muscle of older subjects after resistance exercise and protein ingestion compared with young subjects, which could be partially due to an increased expression of REDD1 and an impaired anabolic sensitivity.

Effects of Multicomponent Exercise on Functional and Cognitive Parameters of Hypertensive Patients: A Quasi-Experimental Study

PubMed Central

Feriani, Daniele Jardim; Gonçalves, Ivan de Oliveira; Asano, Ricardo Yukio; Aguiar, Samuel da Silva; Uchida, Marco Carlos

2017-01-01

Purpose. The present study aimed to investigate the impact of a 6-month multicomponent exercise program (MCEP) on physical function and cognitive parameters of normotensive (NTS) and hypertensive (HTS) older patients and verify if age can influence the adaptations in response to the exercise. Methods. A total of 218 subjects, 101 NTS and 117 HTS, were recruited and underwent functional and cognitive evaluations before and after six months of a MCEP. The program of exercise was performed twice a week, for 26 weeks. The physical exercises were thought to mimic the activities of daily living and, therefore, aggregated functional and walking exercises. Exercise sessions were performed at moderate intensity. Results. Data indicated that HTS and NST patients showed a similar increase in the performance of walking speed test and one-leg stand test after the MCEP. Regarding age, results did not show differences in the magnitude of adaptations between old and young HTS and NTS patients. Conclusions. Data of the present study indicated that a 6-month MCEP was able to increase equally balance and mobility in NTS and HTS patients. Moreover, data demonstrated that aging did not seem to impair the capacity to adapt in response to exercise in both groups. PMID:28409030

Single-leg squats can predict leg alignment in dancers performing ballet movements in "turnout".

PubMed

Hopper, Luke S; Sato, Nahoko; Weidemann, Andries L

2016-01-01

The physical assessments used in dance injury surveillance programs are often adapted from the sports and exercise domain. Bespoke physical assessments may be required for dance, particularly when ballet movements involve "turning out" or external rotation of the legs beyond that typically used in sports. This study evaluated the ability of the traditional single-leg squat to predict the leg alignment of dancers performing ballet movements with turnout. Three-dimensional kinematic data of dancers performing the single-leg squat and five ballet movements were recorded and analyzed. Reduction of the three-dimensional data into a one-dimensional variable incorporating the ankle, knee, and hip joint center positions provided the strongest predictive model between the single-leg squat and the ballet movements. The single-leg squat can predict leg alignment in dancers performing ballet movements, even in "turned out" postures. Clinicians should pay careful attention to observational positioning and rating criteria when assessing dancers performing the single-leg squat.

Single-leg squats can predict leg alignment in dancers performing ballet movements in “turnout”

PubMed Central

Hopper, Luke S; Sato, Nahoko; Weidemann, Andries L

2016-01-01

The physical assessments used in dance injury surveillance programs are often adapted from the sports and exercise domain. Bespoke physical assessments may be required for dance, particularly when ballet movements involve “turning out” or external rotation of the legs beyond that typically used in sports. This study evaluated the ability of the traditional single-leg squat to predict the leg alignment of dancers performing ballet movements with turnout. Three-dimensional kinematic data of dancers performing the single-leg squat and five ballet movements were recorded and analyzed. Reduction of the three-dimensional data into a one-dimensional variable incorporating the ankle, knee, and hip joint center positions provided the strongest predictive model between the single-leg squat and the ballet movements. The single-leg squat can predict leg alignment in dancers performing ballet movements, even in “turned out” postures. Clinicians should pay careful attention to observational positioning and rating criteria when assessing dancers performing the single-leg squat. PMID:27895518

Effect of supervised, periodized exercise training vs. self-directed training on lean body mass and other fitness variables in health club members.

PubMed

Storer, Thomas W; Dolezal, Brett A; Berenc, Matthew N; Timmins, John E; Cooper, Christopher B

2014-07-01

Conventional wisdom suggests that exercise training with a personal trainer (PTr) is more beneficial for improving health-related fitness than training alone. However, there are no published data that confirm whether fitness club members who exercise with a PTr in the fitness club setting obtain superior results compared with self-directed training. We hypothesized that club members randomized to receive an evidence-based training program would accrue greater improvements in lean body mass (LBM) and other fitness measures than members randomized to self-training. Men, aged 30-44 years, who were members of a single Southern California fitness club were randomized to exercise with a PTr administering a nonlinear periodized training program (TRAINED, N = 17) or to self-directed training (SELF, N = 17); both groups trained 3 days per week for 12 weeks. Lean body mass was determined by dual-energy x-ray absorptiometry. Secondary outcomes included muscle strength 1 repetition maximum (1RM), leg power (vertical jump), and aerobic capacity (V[Combining Dot Above]O2max). TRAINED individuals increased LBM by 1.3 (0.4) kg, mean (SEM) vs. no change in SELF, p = 0.029. Similarly, significantly greater improvements were seen for TRAINED vs. SELF in chest press strength (42 vs. 19%; p = 0.003), peak leg power (6 vs. 0.6%; p < 0.0001), and V[Combining Dot Above]O2max (7 vs. -0.3%; p = 0.01). Leg press strength improved 38 and 25% in TRAINED and SELF, respectively (p = 0.14). We have demonstrated for the first time in a fitness club setting that members whose training is directed by well-qualified PTrs administering evidence-based training regimens achieve significantly greater improvements in LBM and other dimensions of fitness than members who direct their own training.

"Four legs instead of two"--perspectives on a Nordic walking-based walking programme among people with arthritis.

PubMed

O'Donovan, Rhona; Kennedy, Norelee

2015-01-01

Nordic Walking (NW) is growing in popularity among people with arthritis. The aim of this study was to explore the perspectives of participants with arthritis on a NW-based walking programme including factors contributing to sustained participation in the programme. Three semi-structured focus groups were conducted with a total of 27 participants with various types of arthritis. The groups consisted of participants who completed a NW-based walking programme in the previous 4 years. Only participants who had sustained involvement in the walking group were included. Groups were audio-recorded, transcribed verbatim and thematic analysis was performed. Participants reported that the walking programme offered numerous benefits. Two distinct themes emerged: (1) "four legs instead of two legs" and (2) "a support group". Theme 1 incorporates the physical, psychological and educational benefits that stem from involvement in a walking group while Theme 2 incorporates the benefits of social support in group-based activity. Several benefits of a NW-based walking programme from the perspectives of individuals with arthritis who engage in group-based walking programmes were identified. The benefits may encourage sustained participation and justify the promotion of NW as an intervention for people with arthritis. Considering how to sustain exercise participation is important to ensure continued benefits from physical activity participation. A community-based Nordic walking-based walking programme for people with arthritis improved exercise knowledge and confidence to exercise. Group exercise is valuable in providing support and motivation to continue exercising.

Lower skin temperature decreases maximal cycling performance.

PubMed

Imai, Daiki; Okazaki, Kazunobu; Matsumura, Shinya; Suzuki, Takashi; Miyazawa, Taiki; Suzuki, Akina; Takeda, Ryosuke; Hamamoto, Takeshi; Zako, Tetsuo; Kawabata, Takashi; Miyagawa, Toshiaki

2011-12-01

It is known that external cooling of body regions involved in exercise, prior to exercise, decreases anaerobic performance. However, there have been no studies reporting the effects of whole body skin surface cooling before exercise on maximal anaerobic capacity. In order to clarify the effects, we compared power output during the Wingate anaerobic test between preconditioning by exposure to temperature 10 degrees C and 25 degrees C. Eight healthy males carried out the Wingate test for 30 seconds, after pre-conditioning for 60 minutes using a perfusion suit with water at a temperature of 10 degrees C or 25 degrees C. We evaluated the peak power (PP) and peak power slope (PS) of the power output. Mean skin temperature (T(sk)) at 60 minutes of pre-conditioning in the 10 degrees C trial was significantly lower than in the 25 degrees C trial (p < 0.05). PP and also PS were significantly lower in the 10 degrees C trial than in the 25 degrees C trial. Changes (Δ) in PP between the 10 degrees C trial and the 25 degrees C trial were strongly correlated with ΔT(sk) and Δ in thigh and leg skin temperature (ΔT(thigh) and ΔT(leg), respectively), whereas ΔPS was strongly correlated with ΔT(sk), but not with ΔT(thigh) and ΔT(leg). Whole body skin surface cooling prior to exercise restricts anaerobic capacity, especially in the initial phase of exercise.

Effect of different types of exercise on postural balance in elderly women: a randomized controlled trial.

PubMed

de Oliveira, Marcio R; da Silva, Rubens A; Dascal, Juliana B; Teixeira, Denilson C

2014-01-01

Different types of exercise are indicated for the elderly to prevent functional capacity limitations due to aging and reduce the risk of falls. This study aimed to evaluate the effect of three different exercises (mini-trampoline, MT; aquatic gymnastics, AG and general floor gymnastics, GG) on postural balance in elderly women. Seventy-four physically independent elderly women, mean age 69±4 years, were randomly assigned to three intervention groups: (1) MT (n=23), (2) AG (n=28), and (3) GG (n=23). Each group performed physical training, including cardiorespiratory, muscular strength and endurance, flexibility and sensory-motor exercises for 12 weeks. To determine the effects on each intervention group, five postural balance tasks were performed on a force platform (BIOMEC 400): the two-legged stand with eyes open (TLEO) and two-legged stand with eyes closed (TLEC); the semi-tandem stand with eyes open (STEO) and semi-tandem stand with eyes closed (STEC) and the one-legged stand. Three trials were performed for each task (with 30s of rest between them) and the mean was used to compute balance parameters such as center of pressure (COP) sway movements. All modalities investigated such as the MT, AG and GG were significantly (P<0.05) efficient in improving the postural balance of elderly women after 12 weeks of training. These results provide further evidence concerning exercise and balance for promoting health in elderly women. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Effects of a pre-workout supplement on hyperemia following leg extension resistance exercise to failure with different resistance loads.

PubMed

Martin, Jeffrey S; Mumford, Petey W; Haun, Cody T; Luera, Micheal J; Muddle, Tyler W D; Colquhoun, Ryan J; Feeney, Mary P; Mackey, Cameron S; Roberson, Paul A; Young, Kaelin C; Pascoe, David D; DeFreitas, Jason M; Jenkins, Nathaniel D M; Roberts, Michael D

2017-01-01

We sought to determine if a pre-workout supplement (PWS), containing multiple ingredients thought to enhance blood flow, increases hyperemia associated with resistance training compared to placebo (PBO). Given the potential interaction with training loads/time-under-tension, we evaluated the hyperemic response at two different loads to failure. Thirty males participated in this double-blinded study. At visit 1, participants were randomly assigned to consume PWS (Reckless™) or PBO (maltodextrin and glycine) and performed four sets of leg extensions to failure at 30% or 80% of their 1-RM 45-min thereafter. 1-wk. later (visit 2), participants consumed the same supplement as before, but exercised at the alternate load. Heart rate (HR), blood pressure (BP), femoral artery blood flow, and plasma nitrate/nitrite (NOx) were assessed at baseline (BL), 45-min post-PWS/PBO consumption (PRE), and 5-min following the last set of leg extensions (POST). Vastus lateralis near infrared spectroscopy (NIRS) was employed during leg extension exercise. Repeated measures ANOVAs were performed with time, supplement, and load as independent variables and Bonferroni correction applied for multiple post-hoc comparisons. Data are reported as mean ± SD. With the 30% training load compared to 80%, significantly more repetitions were performed ( p  < 0.05), but there was no difference in total volume load ( p  > 0.05). NIRS derived minimum oxygenated hemoglobin (O 2 Hb) was lower in the 80% load condition compared to 30% for all rest intervals between sets of exercise ( p  < 0.0167). HR and BP did not vary as a function of supplement or load. Femoral artery blood flow at POST was higher independent of exercise load and treatment. However, a time*supplement*load interaction was observed revealing greater femoral artery blood flow with PWS compared to PBO at POST in the 80% (+56.8%; p  = 0.006) but not 30% load condition (+12.7%; p  = 0.476). Plasma NOx was ~3-fold higher with PWS compared to PBO at PRE and POST ( p  < 0.001). Compared to PBO, the PWS consumed herein augmented hyperemia following multiple sets to failure at 80% of 1-RM, but not 30%. This specificity may be a product of interaction with local perturbations (e.g., reduced tissue oxygenation levels [minimum O 2 Hb] in the 80% load condition) and/or muscle fiber recruitment.

Keeping Fit: Inhale, Exhale

ERIC Educational Resources Information Center

Crupi, Jeffrey

2005-01-01

This article describes yoga and stretching exercises that can quickly restore order and bring a sense of calm to the classroom. All the exercises described can be done sitting cross-legged on the floor or on a small exercise mat or carpet square. Just a few minutes of yoga in the morning, between classes, or in the afternoon can certainly help to…

An Analysis of Muscle Activities of Healthy Women during Pilates Exercises in a Prone Position.

PubMed

Kim, Bo-In; Jung, Ju-Hyeon; Shim, Jemyung; Kwon, Hae-Yeon; Kim, Haroo

2014-01-01

[Purpose] This study analyzed the activities of the back and hip muscles during Pilates exercises conducted in a prone position. [Subjects] The subjects were 18 healthy women volunteers who had practiced at a Pilates center for more than three months. [Methods] The subjects performed three Pilates exercises. To examine muscle activity during the exercises, 8-channel surface electromyography (Noraxon USA, Inc., Scottsdale, AZ) was used. The surface electrodes were attached to the bilateral latissimus dorsi muscle, multifidus muscle, gluteus maximus, and semitendinous muscle. Three Pilates back exercises were compared: (1) double leg kick (DLK), (2) swimming (SW), and (3) leg beat (LB). Electrical muscle activation was normalized to maximal voluntary isometric contraction. Repeated measures analysis of variance was performed to assess the differences in activation levels among the exercises. [Results] The activity of the multifidus muscle was significantly high for the SW (52.3±11.0, 50.9±9.8) and LB exercises(51.8±12.8, 48.3±13.9) and the activity of the semitendinosus muscle was higher for the LB exercise (49.2±8.7, 52.9±9.3) than for the DLK and SW exercises. [Conclusion] These results may provide basic material for when Pilates exercises are performed in a prone position and may be useful information on clinical Pilates for rehabilitation programs.

Age-related differences in lean mass, protein synthesis and skeletal muscle markers of proteolysis after bed rest and exercise rehabilitation

PubMed Central

Tanner, Ruth E; Brunker, Lucille B; Agergaard, Jakob; Barrows, Katherine M; Briggs, Robert A; Kwon, Oh Sung; Young, Laura M; Hopkins, Paul N; Volpi, Elena; Marcus, Robin L; LaStayo, Paul C; Drummond, Micah J

2015-01-01

Abstract Bed rest-induced muscle loss and impaired muscle recovery may contribute to age-related sarcopenia. It is unknown if there are age-related differences in muscle mass and muscle anabolic and catabolic responses to bed rest. A secondary objective was to determine if rehabilitation could reverse bed rest responses. Nine older and fourteen young adults participated in a 5-day bed rest challenge (BED REST). This was followed by 8 weeks of high intensity resistance exercise (REHAB). Leg lean mass (via dual-energy X-ray absorptiometry; DXA) and strength were determined. Muscle biopsies were collected during a constant stable isotope infusion in the postabsorptive state and after essential amino acid (EAA) ingestion on three occasions: before (PRE), after bed rest and after rehabilitation. Samples were assessed for protein synthesis, mTORC1 signalling, REDD1/2 expression and molecular markers related to muscle proteolysis (MURF1, MAFBX, AMPKα, LC3II/I, Beclin1). We found that leg lean mass and strength decreased in older but not younger adults after bedrest (P < 0.05) and was restored after rehabilitation. EAA-induced mTORC1 signalling and protein synthesis increased before bed rest in both age groups (P < 0.05). Although both groups had blunted mTORC1 signalling, increased REDD2 and MURF1 mRNA after bedrest, only older adults had reduced EAA-induced protein synthesis rates and increased MAFBX mRNA, p-AMPKα and the LC3II/I ratio (P < 0.05). We conclude that older adults are more susceptible than young persons to muscle loss after short-term bed rest. This may be partially explained by a combined suppression of protein synthesis and a marginal increase in proteolytic markers. Finally, rehabilitation restored bed rest-induced deficits in lean mass and strength in older adults. Key points Five days of bed rest resulted in a reduction in leg lean mass and strength in older adults. After bed rest, older (but not younger) adults had reduced amino acid-induced anabolic sensitivity (blunted muscle protein synthesis; MPS) and enhanced markers associated with the ubiquitin proteasome and autophagy–lysosomal systems (increase in molecular markers related to muscle proteolysis). Younger adults did not lose leg lean mass (via DXA) after 5 days of bed rest despite blunted amino acid-induced mTORC1 signalling and increased skeletal muscle REDD1, REDD2 and MURF1 mRNA expression. Exercise rehabilitation restored bed rest-induced deficits in lean mass, strength, nutrient-induced protein anabolism (protein synthesis and mTORC1 signalling) and select muscle proteolytic markers in older adults. PMID:26173027

Longitudinal changes in body composition and metabolic profile between exercise clinical trials in men with chronic spinal cord injury

PubMed Central

Gorgey, Ashraf S.; Martin, Heather; Metz, Alyse; Khalil, Refka E.; Dolbow, David R.; Gater, David R.

2016-01-01

Study design Longitudinal design. Objectives The study was undertaken to determine the effects of cessation of exercise interventions on body composition and metabolic profiles in men with chronic SCI. Settings Clinical trials within a Medical Center. Methods Eleven men with motor complete SCI were followed on average over a period of 2.5 years. Six men were involved in two different exercise interventions (functional electrical stimulation cycling versus arm cycling ergometer), 5 days/week for 16 weeks (exercise group), and five men served as a control (control group). Anthropometrics and dual energy X-ray absorptiometry (DXA) were captured to measure changes in lean mass (LM), fat mass (FM), percentage FM before, immediately after exercise, and after a period of 2.5 years. Basal metabolic rate (BMR) and lipid panel were also measured. Results Thigh circumference increased by 8.5% following exercise (P = 0.042) and remained 6.4% greater than baseline measurements (P = 0.012). Leg LM increased by 9% following the exercise intervention (P = 0.03) and decreased by 16% in the follow-up visit (P = 0.02). Percentage trunk and total body FM increased by 4.5% (P = 0.008) and 3.5% (P = 0.019) in the follow-up visit, respectively, and whole body LM increased by 8.4% and decreased back by 5.4% following a 2.5 year-period. BMR significantly decreased by 15.5% following the exercise (P = 0.029) interventions. Conclusion Exercise training is accompanied with positive changes in body composition as well as compensatory decrease in BMR, that regressed back following 2.5 years of exercise cessation. Participation in an exercise trial is unlikely to confound the measurements of a follow-up trial. PMID:27077574

Cyclical blood flow restriction resistance exercise: a potential parallel to remote ischemic preconditioning?

PubMed

Sprick, Justin D; Rickards, Caroline A

2017-11-01

Remote ischemic preconditioning (RIPC) is characterized by the cyclical application of limb blood flow restriction and reperfusion and has been shown to protect vital organs during a subsequent ischemic insult. Blood flow restriction exercise (BFRE) similarly combines bouts of blood flow restriction with low-intensity exercise and thus could potentially emulate the protection demonstrated by RIPC. One concern with BFRE, however, is the potential for an augmented rise in sympathetic outflow due to greater activation of the exercise pressor reflex. Because of the use of lower workloads, however, we hypothesized that BFRE would elicit an attenuated increase in sympathetic outflow [assessed via plasma norepinephrine (NE) and mean arterial pressure (MAP)] and middle cerebral artery velocity (MCAv) when compared with conventional exercise (CE). Fifteen subjects underwent two leg press exercise interventions: 1 ) BFRE-220 mmHg bilateral thigh occlusion at 20% 1 rep-max (1RM), and 2 ) CE-65% 1RM without occlusion. Each condition consisted of 4 × 5-min cycles of exercise, with 3 × 10-reps in each cycle. Five minutes of rest and reperfusion (for BFRE) followed each cycle. MAP increased with exercise ( P < 0.001) and was 4-5 mmHg higher with CE versus BFRE ( P ≤ 0.09). Mean MCAv also increased with exercise ( P < 0.001) and was higher with CE compared with BFRE during the first bout of exercise only ( P = 0.07). Plasma NE concentration increased with CE only ( P < 0.001) and was higher than BFRE throughout exercise ( P ≤ 0.02). The attenuated sympathetic response, combined with similar cerebrovascular responses, suggest that cyclical BFRE could be explored as an alternative to CE in the clinical setting. Copyright © 2017 the American Physiological Society.

"Float first and kick for your life": Psychophysiological basis for safety behaviour on accidental short-term cold water immersion.

PubMed

Barwood, Martin J; Burrows, Holly; Cessford, Jess; Goodall, Stuart

2016-02-01

Accidental cold-water immersion (CWI) evokes the life threatening cold shock response (CSR) which increases the risk of drowning. Consequently, the safety behaviour selected is critical in determining survival; the present advice is to 'float first' and remain stationary (i.e. rest). We examined whether leg only exercise (i.e., treading water; 'CWI-Kick') immediately on CWI could reduce the symptoms of the CSR, offset the reduction in cerebral blood flow that is known to occur and reduce the CSR's symptoms of breathlessness. We also examined whether perceptual responses instinctive to accidental CWI were exacerbated by this alternative behaviour. We contrasted CWI-Kick to a 'CWI-Rest' condition and a thermoneutral control (35°C); 'TN-Rest'. Seventeen participants were tested (9 males, 8 females). All immersions were standardised; water temperature in cold conditions (i.e., 12°C) was matched ±/0.5°C within participant. Middle cerebral artery blood flow velocity (MCAv) and cardiorespiratory responses were measured along with thermal perception (sensation and comfort) and dyspnoea. Data were analysed using repeated measures ANOVA (alpha level of 0.05). MCAv was significantly reduced in CWI-Rest (-6 (9)%; 1st minute of immersion) but was offset by leg only exercise immediately on cold water entry; CWI-Kick MCAv was never different to TN-Rest (-3 (16)% cf. 5 (4)%). All CWI cardiorespiratory and perceptual responses were different to TN-Rest but were not exacerbated by leg only exercise. Treading water may aid survival by offsetting the reduction in brain blood flow velocity without changing the instinctive behavioural response (i.e. perceptions). "Float first - and kick for your life" would be a suitable amendment to the water safety advice. Copyright © 2015 Elsevier Inc. All rights reserved.

Lack of diurnal effects on periodic exercise during prolonged cold water immersion.

PubMed

Doubt, T J; Smith, D J

1990-03-01

Diurnal effects on periodic exercise were examined in 8 male divers wearing passive thermal protection during whole body immersions in 5 degrees C water for periods of up to 6 h. Studies were done during the course of 5-day air saturation dives at a depth of 1.61 ATA, with immersions beginning at 1000 h (AM) and 2200 h (PM). During each hour of immersion, leg exercise was done for 3 min each at workloads of 50, 70, and 90 W. Heart rate (HR) at each workload increased uniformly with immersion time, without a change in slope of HR vs. workload. No AM or PM differences occurred. AM resting VO2 increased linearly, and to the same extent as PM, with exposure time. VO2 at 50 W also increased at the same rate as resting values. VO2 at 70 and 90 W were similar for AM and PM and did not vary significantly during the 6-h immersions. Temporal increases in exercise HR may reflect cardiac compensation of diminished plasma volume. Workloads greater than or equal to 70 W generate enough metabolic heat in this specific condition to meet the thermogenic requirement. Lack of diurnal effects on exercise variables may be due to environmental conditions suppressing circadian rhythms.

Predicting one repetition maximum equations accuracy in paralympic rowers with motor disabilities.

PubMed

Schwingel, Paulo A; Porto, Yuri C; Dias, Marcelo C M; Moreira, Mônica M; Zoppi, Cláudio C

2009-05-01

Predicting one repetition maximum equations accuracy in paralympic rowers Resistance training intensity is prescribed using percentiles of the maximum strength, defined as the maximum tension generated for a muscle or muscular group. This value is found through the application of the one maximal repetition (1RM) test. One maximal repetition test demands time and still is not appropriate for some populations because of the risk it offers. In recent years, the prediction of maximal strength, through predicting equations, has been used to prevent the inconveniences of the 1RM test. The purpose of this study was to verify the accuracy of 12 1RM predicting equations for disabled rowers. Nine male paralympic rowers (7 one-leg amputated rowers and 2 cerebral paralyzed rowers; age, 30 +/- 7.9 years; height, 175.1 +/- 5.9 cm; weight, 69 +/- 13.6 kg) performed 1RM test for lying T-bar row and flat barbell bench press exercises to determine upper-body strength and leg press exercise to determine lower-body strength. One maximal repetition test was performed, and based on submaximal repetitions loads, several linear and exponential equations models were tested with regard of their accuracy. We did not find statistical differences for lying T-bar row and bench press exercises between measured and predicted 1RM values (p = 0.84 and 0.23 for lying T-bar row and flat barbell bench press, respectively); however, leg press exercise reached a high significant difference between measured and predicted values (p < 0.01). In conclusion, rowers with motor disabilities tolerate 1RM testing procedures, and predicting 1RM equations are accurate for bench press and lying T-bar row, but not for leg press, in this kind of athlete.

Strength, power, and muscular endurance exercise and elite rowing ergometer performance.

PubMed

Lawton, Trent W; Cronin, John B; McGuigan, Michael R

2013-07-01

Knowledge of the relationship between weight room exercises and various rowing performance measures is limited; this information would prove useful for sport-specific assessment of individual needs and exercise prescription. The purpose of this study was to establish strength, power, and muscular endurance exercises for weight room training, which are strong determinants of success in specific performance measures used to assess elite rowers. Nineteen heavyweight elite males determined their repetition maximum (RM) loads for exercises using a Concept 2 DYNO [5, 30, 60 and 120RM leg pressing and seated arm pulling (in Joules)] and free weights [1RM power clean (in kilograms) and 6RM bench pull (in kilograms and watts)]. Rowing performance measures included a 7-stage blood lactate response ergometer test (aerobic condition), time trials (500, 2000, and 5000 m), a peak stroke power test, and a 60-minute distance trial. Pearson correlation moments (r ≥ 0.7) and stepwise multiple linear regression calculations (R ≥ 50%) were used to establish strong common variances between weight room exercises and rowing ergometer performance (p ≤ 0.05). Weight room exercises were strong predictors of 2000-m, 500-m time (in seconds), and peak stroke power performance measures only. Bench pull power (in watts) and 1RM power clean (in kilograms) were the best 2-factor predictors of peak stroke power (R = 73%; standard error of the estimates [SEE] = 59.6 W) and 500 m (R = 70%; SEE = 1.75 seconds); while 5RM leg pressing (in Joules) and either 6RM bench pull (kg) or 60RM seated arm pulling (in Joules) the best predictors of 2000 m (R = 59%; SEE = 6.3 seconds and R = 57%; SEE = 6.4 seconds, respectively). Recommended exercises for weight room training include a 1RM power clean, 6RM bench pull, 5RM leg press, and 60RM seated arm pulling.

Effects of body position on the ventilatory response following an impulse exercise in humans.

PubMed

Haouzi, Philippe; Chenuel, Bruno; Chalon, Bernard

2002-04-01

The aim of this study was to identify some of the mechanisms that could be involved in blunted ventilatory response (VE) to exercise in the supine (S) position. The contribution of the recruitment of different muscle groups, the activity of the cardiac mechanoreceptors, the level of arterial baroreceptor stimulation, and the hemodynamic effects of gravity on the exercising muscles was analyzed during upright (U) and S exercise. Delayed rise in VE and pulmonary gas exchange following an impulselike change in work rate (supramaximal leg cycling at 240 W for 12 s) was measured in seven healthy subjects and six heart transplant patients both in U and S positions. This approach allows study of the relationship between the rise in VE and O2 uptake (VO2) without the confounding effects of contractions of different muscle groups. These responses were compared with those triggered by an impulselike change in work rate produced by the arms, which were positioned at the same level as the heart in S and U positions to separate effects of gravity on postexercising muscles from those on the rest of the body. Despite superimposable VO2 and CO2 output responses, the delayed VE response after leg exercise was significantly lower in the S posture than in the U position for each control subject and cardiac-transplant patient (-2.58 +/- 0.44 l and -3.52 +/- 1.11 l/min, respectively). In contrast, when impulse exercise was performed with the arms, reduction of ventilatory response in the S posture reached, at best, one-third of the deficit after leg exercise and was always associated with a reduction in VO2 of a similar magnitude. We concluded that reduction in VE response to exercise in the S position is independent of the types (groups) of muscles recruited and is not critically dependent on afferent signals originating from the heart but seems to rely on some of the effects of gravity on postexercising muscles.

Abnormal heart rate recovery and chronotropic incompetence on exercise in chronic obstructive pulmonary disease.

PubMed

Gupta, Mansi; Bansal, Vishal; Chhabra, Sunil K

2013-08-01

Chronotropic incompetence (CI; failure to reach the targeted heart rate (HR) on exercise) and a delayed HR recovery (HRR; ≤12 beats decline within the first minute after cessation) reflect autonomic dysfunction (AD) and predict adverse cardiac prognosis. As chronic obstructive pulmonary disease (COPD) is known to be associated with AD, we hypothesized that these patients may manifest these responses on exercise. The prevalence and predictors of these responses in COPD and their association with its severity have not been evaluated. Normoxemic, stable male patients with COPD (n = 39) and 11 healthy controls underwent lung function testing and incremental leg ergometry. HR responses were monitored during exercise and recovery to compute the HRR and CI. Of all the patients, 33 (84.6%) had at least one of the two exercise responses as abnormal, with the majority (23, 58.9%) having both an abnormal HRR and CI. The frequency of abnormal responses increased with increasing Global Initiative for Chronic Obstructive Lung Disease stage and body mass index, airflow obstruction, dyspnoea and exercise capacity index. After adjusting for smoking history and post-bronchodilator forced expiratory volume in 1 second, only a reduced diffusion capacity for carbon monoxide predicted abnormal HRR, though weakly. We concluded that abnormal HRR and CI are common in patients with COPD. These responses are observed with increasing frequency as the severity of disease increases.

A progressive 5-week exercise therapy program leads to significant improvement in knee function early after anterior cruciate ligament injury.

PubMed

Eitzen, Ingrid; Moksnes, Håvard; Snyder-Mackler, Lynn; Risberg, May Arna

2010-11-01

Prospective cohort study without a control group. Firstly, to present our 5-week progressive exercise therapy program in the early stage after anterior cruciate ligament (ACL) injury. Secondly, to evaluate changes in knee function after completion of the program for patients with ACL injury in general and also when classified as potential copers or noncopers, and, finally, to examine potential adverse events. Few studies concerning early-stage ACL rehabilitation protocols exist. Consequently, little is known about the tolerance for, and outcomes from, short-term exercise therapy programs in the early stage after injury. One-hundred patients were included in a 5-week progressive exercise therapy program, within 3 months after injury. Knee function before and after completion of the program was evaluated from isokinetic quadriceps and hamstrings muscle strength tests, 4 single-leg hop tests, 2 different self-assessment questionnaires, and a global rating of knee function. A 2-way mixed-model analysis of variance was conducted to evaluate changes from pretest to posttest for the limb symmetry index for muscle strength and single-leg hop tests, and the change in scores for the patient-reported questionnaires. In addition, absolute values and the standardized response mean for muscle strength and single-leg hop tests were calculated at pretest and posttest for the injured and uninjured limb. Adverse events during the 5-week period were recorded. The progressive 5-week exercise therapy program led to significant improvements (P<.05) in knee function from pretest to posttest both for patients classified as potential copers and noncopers. Standardized response mean values for changes in muscle strength and single-leg hop performance from pretest to posttest for the injured limb were moderate to strong (0.49-0.84), indicating the observed improvements to be clinically relevant. Adverse events occurred in 3.9% of the patients. Short-term progressive exercise therapy programs are well tolerated and should be incorporated in early-stage ACL rehabilitation, either to improve knee function before ACL reconstruction or as a first step in further nonoperative management. Therapy, level 2b.

Precooling leg muscle improves intermittent sprint exercise performance in hot, humid conditions.

PubMed

Castle, Paul C; Macdonald, Adam L; Philp, Andrew; Webborn, Anthony; Watt, Peter W; Maxwell, Neil S

2006-04-01

We used three techniques of precooling to test the hypothesis that heat strain would be alleviated, muscle temperature (Tmu) would be reduced, and as a result there would be delayed decrements in peak power output (PPO) during exercise in hot, humid conditions. Twelve male team-sport players completed four cycling intermittent sprint protocols (CISP). Each CISP consisted of twenty 2-min periods, each including 10 s of passive rest, 5 s of maximal sprint against a resistance of 7.5% body mass, and 105 s of active recovery. The CISP, preceded by 20 min of no cooling (Control), precooling via an ice vest (Vest), cold water immersion (Water), and ice packs covering the upper legs (Packs), was performed in hot, humid conditions (mean +/- SE; 33.7 +/- 0.3 degrees C, 51.6 +/- 2.2% relative humidity) in a randomized order. The rate of heat strain increase during the CISP was faster in Control than Water and Packs (P < 0.01), but it was similar to Vest. Packs and Water blunted the rise of Tmu until minute 16 and for the duration of the CISP (40 min), respectively (P < 0.01). Reductions in PPO occurred from minute 32 onward in Control, and an increase in PPO by approximately 4% due to Packs was observed (main effect; P < 0.05). The method of precooling determined the extent to which heat strain was reduced during intermittent sprint cycling, with leg precooling offering the greater ergogenic effect on PPO than either upper body or whole body cooling.

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.

The effects of self-directed home exercise with serial telephone contacts on physical functions and quality of life in elderly people at high risk of locomotor dysfunction.

PubMed

Aoki, Kana; Sakuma, Mayumi; Ogisho, Noriyuki; Nakamura, Kozo; Chosa, Etsuo; Endo, Naoto

2015-01-01

Exercise is essential for maintaining quality of life (QOL) in elderly individuals. However, adherence to exercise programs is low. Here, we assessed the effectiveness of a self-directed home exercise program with serial telephone contacts to encourage exercise adherence among elderly individuals at high risk of locomotor dysfunction. We recruited community-dwelling adults (ｧ65 years) in Niigata, Japan, who were targets of the long-term care prevention project for locomotor dysfunction but did not participate in the government-sponsored prevention programs. The study was conducted from November 2011 to October 2012. Participants received exercise instruction and performed exercises independently for 3 months with serial telephone contacts. The single-leg stance and five-times sit-to-stand tests were used to assess physical function. The SF-8 was used to measure health-related QOL. Ninety-seven participants were enrolled in the study, representing 2.5% of eligible people;87 completed the intervention. Scores from physical function tests were significantly improved by the intervention, as were 7 of eight SF-8 subscales. Adherence was 85.4% for the single-leg standing exercise and 82.1% for squatting. Thus, self-directed home exercise with serial telephone contacts improved physical function and health-related QOL, representing a promising model for preventing the need for long-term care due to locomotor dysfunction.

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.

Unipedal standing exercise and hip bone mineral density in postmenopausal women: a randomized controlled trial.

PubMed

Sakai, Akinori; Oshige, Toshihisa; Zenke, Yukichi; Yamanaka, Yoshiaki; Nagaishi, Hitoshi; Nakamura, Toshitaka

2010-01-01

The aim of this study was to test the effect of unipedal standing exercise on bone mineral density (BMD) of the hip in postmenopausal women. Japanese postmenopausal women (n = 94) were assigned at random to an exercise or control group (no exercise). The 6-month exercise program consisted of standing on a single foot for 1 min per leg 3 times per day. BMD of the hip was measured by dual-energy X-ray absorptiometry. There was no significant difference in age and baseline hip BMD between the exercise group (n = 49) and control group (n = 45). Exercise did not improve hip BMD compared with the control group. Stepwise regression analysis identified old age as a significant determinant (p = 0.034) of increased hip total BMD at 6 months after exercise. In 31 participants aged >/=70 years, the exercise group (n = 20) showed significant increase in the values of hip BMD at the areas of total (p = 0.008), intertrochanteric (p = 0.023), and Ward's triangle (p = 0.032). The same parameters were decreased in the control group (n = 11). The percent changes in hip BMD of the exercise group were not significantly different from those of the control group either in the participants with low baseline hip total BMD (<80% of the young adult mean) or high baseline hip total BMD (> or =80% of the young adult mean). In conclusion, unipedal standing exercise for 6 months did not improve hip BMD in Japanese postmenopausal women. Effect of exercise on hip total BMD was age dependent. In participants aged > or =70 years, the exercise significantly increased hip total BMD.

Exercise for falls prevention in Parkinson disease

PubMed Central

Sherrington, Catherine; Lord, Stephen R.; Close, Jacqueline C.T.; Heritier, Stephane; Heller, Gillian Z.; Howard, Kirsten; Allen, Natalie E.; Latt, Mark D.; Murray, Susan M.; O'Rourke, Sandra D.; Paul, Serene S.; Song, Jooeun; Fung, Victor S.C.

2015-01-01

Objective: To determine whether falls can be prevented with minimally supervised exercise targeting potentially remediable fall risk factors, i.e., poor balance, reduced leg muscle strength, and freezing of gait, in people with Parkinson disease. Methods: Two hundred thirty-one people with Parkinson disease were randomized into exercise or usual-care control groups. Exercises were practiced for 40 to 60 minutes, 3 times weekly for 6 months. Primary outcomes were fall rates and proportion of fallers during the intervention period. Secondary outcomes were physical (balance, mobility, freezing of gait, habitual physical activity), psychological (fear of falling, affect), and quality-of-life measures. Results: There was no significant difference between groups in the rate of falls (incidence rate ratio [IRR] = 0.73, 95% confidence interval [CI] 0.45–1.17, p = 0.18) or proportion of fallers (p = 0.45). Preplanned subgroup analysis revealed a significant interaction for disease severity (p < 0.001). In the lower disease severity subgroup, there were fewer falls in the exercise group compared with controls (IRR = 0.31, 95% CI 0.15–0.62, p < 0.001), while in the higher disease severity subgroup, there was a trend toward more falls in the exercise group (IRR = 1.61, 95% CI 0.86–3.03, p = 0.13). Postintervention, the exercise group scored significantly (p < 0.05) better than controls on the Short Physical Performance Battery, sit-to-stand, fear of falling, affect, and quality of life, after adjusting for baseline performance. Conclusions: An exercise program targeting balance, leg strength, and freezing of gait did not reduce falls but improved physical and psychological health. Falls were reduced in people with milder disease but not in those with more severe Parkinson disease. Classification of evidence: This study provides Class III evidence that for patients with Parkinson disease, a minimally supervised exercise program does not reduce fall risk. This study lacked the precision to exclude a moderate reduction or modest increase in fall risk from exercise. Trial registration: Australian New Zealand Clinical Trials Registry (ACTRN12608000303347). PMID:25552576

Exercise for falls prevention in Parkinson disease: a randomized controlled trial.

PubMed

Canning, Colleen G; Sherrington, Catherine; Lord, Stephen R; Close, Jacqueline C T; Heritier, Stephane; Heller, Gillian Z; Howard, Kirsten; Allen, Natalie E; Latt, Mark D; Murray, Susan M; O'Rourke, Sandra D; Paul, Serene S; Song, Jooeun; Fung, Victor S C

2015-01-20

To determine whether falls can be prevented with minimally supervised exercise targeting potentially remediable fall risk factors, i.e., poor balance, reduced leg muscle strength, and freezing of gait, in people with Parkinson disease. Two hundred thirty-one people with Parkinson disease were randomized into exercise or usual-care control groups. Exercises were practiced for 40 to 60 minutes, 3 times weekly for 6 months. Primary outcomes were fall rates and proportion of fallers during the intervention period. Secondary outcomes were physical (balance, mobility, freezing of gait, habitual physical activity), psychological (fear of falling, affect), and quality-of-life measures. There was no significant difference between groups in the rate of falls (incidence rate ratio [IRR] = 0.73, 95% confidence interval [CI] 0.45-1.17, p = 0.18) or proportion of fallers (p = 0.45). Preplanned subgroup analysis revealed a significant interaction for disease severity (p < 0.001). In the lower disease severity subgroup, there were fewer falls in the exercise group compared with controls (IRR = 0.31, 95% CI 0.15-0.62, p < 0.001), while in the higher disease severity subgroup, there was a trend toward more falls in the exercise group (IRR = 1.61, 95% CI 0.86-3.03, p = 0.13). Postintervention, the exercise group scored significantly (p < 0.05) better than controls on the Short Physical Performance Battery, sit-to-stand, fear of falling, affect, and quality of life, after adjusting for baseline performance. An exercise program targeting balance, leg strength, and freezing of gait did not reduce falls but improved physical and psychological health. Falls were reduced in people with milder disease but not in those with more severe Parkinson disease. This study provides Class III evidence that for patients with Parkinson disease, a minimally supervised exercise program does not reduce fall risk. This study lacked the precision to exclude a moderate reduction or modest increase in fall risk from exercise. Australian New Zealand Clinical Trials Registry (ACTRN12608000303347). © 2014 American Academy of Neurology.

Biomechanical Modeling of Split-leg Squat and Heel Raise on the Hybrid Ultimate Lifting Kit (HULK)

NASA Technical Reports Server (NTRS)

Thompson, William K.; Gallo, Christopher A.; Lewandowski, Beth E.; Jagodnik, Kathleen M.; Humphreys, Brad; Funk, Justin; Funk, Nathan; Dewitt, John K.

2016-01-01

Long duration space travel will expose astronauts to extended periods of reduced gravity. Since gravity is not present to aid loading, astronauts will use resistive and aerobic exercise regimes for the duration of the space flight to minimize the loss of bone density, muscle mass and aerobic capacity that occurs during exposure to a reduced gravity environment. Unlike the International Space Station (ISS), the area available for an exercise device in the next generation of spacecraft is limited and therefore compact resistance exercise device prototypes are being developed. The Advanced Resistive Exercise Device (ARED) currently on the ISS is being used as a benchmark for the functional performance of these new devices. Biomechanical data collection and computational modeling aid the device design process by quantifying the joint torques and musculoskeletal forces that occur during exercises performed on the prototype devices. Computational models currently use OpenSim software, an open source code for musculoskeletal modeling, with biomechanical input data from subjects for estimation of muscle and joint loads. Subjects are instrumented with reflective markers for motion capture data collection while exercising on the Hybrid Ultimate Lifting Kit (HULK) prototype device. Ground reaction force data is collected with force plates under the feet and device loading is recorded through load cells internal to the HULK. This data is input into the OpenSim biomechanical model, which has been scaled to match the anthropometrics of the test subject, to calculate the loads on the body. Multiple exercises are performed and evaluated during a test session such as a full squat, single leg squat, heel raise and dead lift. Variables for these exercises include applied device load, narrow or wide foot stance, slow or fast cadence and the harness or long bar interface between the test subject and the device. Data from free weights are compared to the resistively loaded exercise device. The focus of this presentation is to summarize the results from the single-leg squat and heel raise exercises performed during three sessions occurring in 2015. Differences in loading configuration, cadence and stance produce differences in kinematics, joint toques and force and muscle forces.

The effect of vertical whole-body vibration on lower limb muscle activation in elderly adults: Influence of vibration frequency, amplitude and exercise.

PubMed

Lam, Freddy M H; Liao, L R; Kwok, Timothy C Y; Pang, Marco Y C

2016-06-01

This study aimed to investigate how whole-body vibration (WBV) and exercise and their interactions influenced leg muscle activity in elderly adults. An experimental study with repeated measures design that involved a group of ambulatory, community-dwelling elderly adults (n=30; 23 women; mean age=61.4±5.3years). Muscle activity of the vastus lateralis (VL), biceps femoris (BF), tibialis anterior (TA), and gastrocnemius (GS) was measured by surface electromyography (EMG), while participants were performing seven different exercises during 4 WBV conditions (condition 1: frequency=30Hz, amplitude=0.6mm, intensity=2.25 units of Earth's gravity (g); condition 2: 30Hz, 0.9mm, 3.40g; condition 3: 40Hz, 0.6mm, 3.65g; condition 4: 40Hz, 0.9mm, 5.50g) and a no-WBV condition in a single experimental session. Significantly greater muscle activity was recorded in VL (3%-148%), BF (16%-202%), and GS (19% -164%) when WBV was added to the exercises, compared with the same exercises without WBV (p≤0.015). The effect of vibration intensity on EMG amplitude was exercise-dependent in VL (p=0.002), and this effect was marginally significant in GS (p=0.052). The EMG activity induced by the four WBV intensities was largely similar, and was the most pronounced during static erect standing and static single-leg standing. The EMG amplitude of majority of leg muscles tested was significantly greater during WBV exposure compared with the no-WBV condition. Low-intensity WBV can induce muscle activity as effectively as higher-intensity protocols, and may be the preferred choice for frail elderly adults. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Twins Bed Rest Project: LBNP/Exercise Minimizes Changes in Lean Leg Mass, Strength and Endurance

NASA Technical Reports Server (NTRS)

Amorim, Fabiano T.; Schneider, Suzanne M.; Lee, Stuart M. C.; Boda, Wanda L.; Watenpaugh, Donald E.; Hargens, Alan R.

2006-01-01

Decreases in muscle strength and endurance frequently are observed in non-weightbearing conditions such as bed rest (BR), spaceflight or limb immobilization. Purpose: Ow purpose was to determine if supine treadmill exercise against simulated gravity, by application of lower body negative pressure (LBNP), prevents loss of lean leg mass, strength and endurance during 30 d of 6deg head-down bed rest (BR). Methods: Fifteen pairs of monozygous twins (8 male, 7 female pairs; 26+/-4 yrs; 170+/-12 cm; 62.6+/-11.3 kg; mean+/-SD) were subjects in the present study. One sibling of each pair of twins was randomly assigned to either an exercise (EX) or non-exercise (CON) group. The EX twin walked/jogged on a vertical treadmill within LBNP chamber 6 d/wk using a 40-min interval exercise protocol at 40-80% of pre-BR VO(sub 2peak). LBNP was adjusted individually for each subject such that footward force was between 1.0 and 1.2 times body weight (-53+/-5 mmHg LBNP). The CON twin performed no exercise during BR. Subjects performed isokinetic knee (60 and 120deg/s) and ankle (60deg/s) testing to assess strength and endurance (End) before and after BR. They also had their lean leg mass (L(sub mass)) evaluated by DEXA before and after BR. Results: Changes in peak torque (T(sub pk)) were smaller for flexion (flex) than for extension (ext) after BR and did not differ between groups. The CON group had larger decreases (P<0.05) in L(sub mass), knee and ankle ext T(sub pk), and knee ext End.

Exercise intensity and muscle hypertrophy in blood flow-restricted limbs and non-restricted muscles: a brief review.

PubMed

Abe, Takashi; Loenneke, Jeremy P; Fahs, Christopher A; Rossow, Lindy M; Thiebaud, Robert S; Bemben, Michael G

2012-07-01

Although evidence for high-intensity resistance training-induced muscle hypertrophy has accumulated over the last several decades, the basic concept of the training can be traced back to ancient Greece: Milo of Croton lifted a bull-calf daily until it was fully grown, which would be known today as progressive overload. Now, in the 21st century, different types of training are being tested and studied, such as low-intensity exercise combined with arterial as well as venous blood flow restriction (BFR) to/from the working muscles. Because BFR training requires the use of a cuff that is placed at the proximal ends of the arms and/or legs, the BFR is only applicable to limb muscles. Consequently, most previous BFR training studies have focused on the physiological adaptations of BFR limb muscles. Muscle adaptations in non-BFR muscles of the hip and trunk are lesser known. Recent studies that have reported both limb and trunk muscle adaptations following BFR exercise training suggest that low-intensity (20-30% of 1RM) resistance training combined with BFR elicits muscle hypertrophy in both BFR limb and non-BFR muscles. However, the combination of leg muscle BFR with walk training elicits muscle hypertrophy only in the BFR leg muscles. In contrast to resistance exercise with BFR, the exercise intensity may be too low during BFR walk training to cause muscle hypertrophy in the non-BFR gluteus maximus and other trunk muscles. Other mechanisms including hypoxia, local and systemic growth factors and muscle cell swelling may also potentially affect the hypertrophic response of non-BFR muscles to BFR resistance exercise. © 2012 The Authors Clinical Physiology and Functional Imaging © 2012 Scandinavian Society of Clinical Physiology and Nuclear Medicine.

NIRS and indocyanine-green-determined muscle blood flow during exercise in humans

NASA Astrophysics Data System (ADS)

Boushel, Robert; Ide, Kojiro; Moller-Sorensen, Hasse; Fernandes, Alvito; Pott, Frank; Secher, Niels H.

1998-01-01

We present a method for determination of muscle blood flow (MBF) using near infrared spectroscopy (NIRS) with indocyanine green (ICG) as the tracer. MBF was quantified using the integrated arterial [ICG] and the accumulation of ICG in muscle. MBF was determined together with ICG-assessed cardiac output (CO) at rest and during incremental cycling. To further modify CO, the same work loads were performed after cardio-selective beta blockade by metoprolol. In one subject both MBF (9 to 110 ml (DOT) 100 g-1 (DOT) min-1) and CO increased linearly with work rate (8 to 19 l (DOT) min-1). Under beta blockade, both the increase in MBF and CO were lower: 5 to 70 ml (DOT) 100 g-1 (DOT) min-1 and 5 to 161 DOT min-1, respectively. During exercise with and without beta blockade, MBF increased with work load to represent a larger proportion of CO. Also, NIRS could detect an attenuated increase in MBF manifest by the restrained CO during leg exercise after cardio-selective beta blockade. Both observations indicate that NIRS detection of indocyanine green provides an estimate of muscle blood flow over the range from rest to intense exercise.

NIRS and indocyanine-green-determined muscle blood flow during exercise in humans

NASA Astrophysics Data System (ADS)

Boushel, Robert; Ide, Kojiro; Moller-Sorensen, Hasse; Fernandes, Alvito; Pott, Frank; Secher, Niels H.

1997-12-01

We present a method for determination of muscle blood flow (MBF) using near infrared spectroscopy (NIRS) with indocyanine green (ICG) as the tracer. MBF was quantified using the integrated arterial [ICG] and the accumulation of ICG in muscle. MBF was determined together with ICG-assessed cardiac output (CO) at rest and during incremental cycling. To further modify CO, the same work loads were performed after cardio-selective beta blockade by metoprolol. In one subject both MBF (9 to 110 ml (DOT) 100 g-1 (DOT) min-1) and CO increased linearly with work rate (8 to 19 l (DOT) min-1). Under beta blockade, both the increase in MBF and CO were lower: 5 to 70 ml (DOT) 100 g-1 (DOT) min-1 and 5 to 161 DOT min-1, respectively. During exercise with and without beta blockade, MBF increased with work load to represent a larger proportion of CO. Also, NIRS could detect an attenuated increase in MBF manifest by the restrained CO during leg exercise after cardio-selective beta blockade. Both observations indicate that NIRS detection of indocyanine green provides an estimate of muscle blood flow over the range from rest to intense exercise.

Association of Serum Uric Acid Levels with Leg Ischemia in Patients with Peripheral Arterial Disease after Treatment.

PubMed

Sotoda, Yoko; Hirooka, Shigeki; Orita, Hiroyuki; Wakabayashi, Ichiro

2017-07-01

We investigated the relationships of serum uric acid levels with the progression of atherosclerosis in patients with peripheral arterial disease (PAD) after treatment. Subjects were male patients diagnosed with PAD. Atherosclerosis at the common carotid artery was evaluated based on its intima-media thickness (IMT). Leg arterial flow was evaluated by measuring ankle-brachial index (ABI) and exercise-induced decrease in ABI. Among various risk factors including age, blood pressure, adiposity, estimated glomerular filtration rate, and blood lipid, blood glucose, uric acid, fibrinogen and C-reactive protein levels, only uric acid levels showed significant correlations with ABI [Pearson's correlation coefficient, -0.292 (p＜0.01)] and leg exercise-induced decrease in ABI [Pearson's correlation coefficient, 0.236 (p＜ 0.05)]. However, there was no significant correlation between uric acid levels and maximum or mean IMT. Odds ratios of subjects with the 3rd tertile versus subjects with the 1st tertile for uric acid levels were significantly higher than the reference level of 1.00 for low ABI [4.44 (95% confidence interval, 1.45-13.65, p＜0.01)] and for high % decrease in ABI after exercise [4.31 (95% confidence interval, 1.34-13.82, p＜0.05)]. The associations of uric acid levels with the indicators of leg ischemia were also found after adjustment for age, history of revascularization therapy, diabetes, smoking, alcohol consumption, body mass index, triglyceride levels, and renal function. Uric acid levels are associated with the degree of leg ischemia in patients with PAD. Further interventional studies are needed to determine whether the correction of uric acid levels is effective in preventing the progression of PAD.

Change in functional balance after an exercise program with Nintendo Wii in Latino patients with cerebral palsy: a case series.

PubMed

Gatica-Rojas, Valeska; Cartes-Velásquez, Ricardo; Méndez-Rebolledo, Guillermo; Olave-Godoy, Felipe; Villalobos-Rebolledo, David

2016-08-01

[Purpose] This study aimed to explore the possibility of improving functional balance using an exercise program with Nintendo and the Balance Board peripheral in subjects with cerebral palsy. [Subjects and Methods] This study included 4 male outpatients of a neurological center. All participants received an exercise program based on the use of Nintendo with the Balance Board peripheral. Training consisted of three 25-min sessions per week for 6 weeks. Each session was guided by a physical therapist. Timed up-and-go and one-leg standing tests were conducted before and after the intervention. [Results] All subjects showed significant improvements in the results of the timed up-and-go test. However, there were no significant changes in the results of the one-leg standing test. [Conclusion] The exercise protocol involving Nintendo with the Balance Board peripheral appears to improve functional dynamic balance in patients with cerebral palsy. However, static functional balance does not improve after 6 weeks of training.

Effectiveness of core stability exercises and recovery myofascial release massage on fatigue in breast cancer survivors: a randomized controlled clinical trial.

PubMed

Cantarero-Villanueva, Irene; Fernández-Lao, Carolina; Del Moral-Avila, Rosario; Fernández-de-Las-Peñas, César; Feriche-Fernández-Castanys, María Belén; Arroyo-Morales, Manuel

2012-01-01

The purpose of the present paper was to evaluate the effects of an 8-week multimodal program focused on core stability exercises and recovery massage with DVD support for a 6-month period in physical and psychological outcomes in breast cancer survivors. A randomized controlled clinical trial was performed. Seventy-eight (n = 78) breast cancer survivors were assigned to experimental (core stability exercises plus massage-myofascial release) and control (usual health care) groups. The intervention period was 8 weeks. Mood state, fatigue, trunk curl endurance, and leg strength were determined at baseline, after the last treatment session, and at 6 months of followup. Immediately after treatment and at 6 months, fatigue, mood state, trunk curl endurance, and leg strength exhibited greater improvement within the experimental group compared to placebo group. This paper showed that a multimodal program focused on core stability exercises and massage reduced fatigue, tension, depression, and improved vigor and muscle strength after intervention and 6 months after discharge.

Change in functional balance after an exercise program with Nintendo Wii in Latino patients with cerebral palsy: a case series

PubMed Central

Gatica-Rojas, Valeska; Cartes-Velásquez, Ricardo; Méndez-Rebolledo, Guillermo; Olave-Godoy, Felipe; Villalobos-Rebolledo, David

2016-01-01

[Purpose] This study aimed to explore the possibility of improving functional balance using an exercise program with Nintendo and the Balance Board peripheral in subjects with cerebral palsy. [Subjects and Methods] This study included 4 male outpatients of a neurological center. All participants received an exercise program based on the use of Nintendo with the Balance Board peripheral. Training consisted of three 25-min sessions per week for 6 weeks. Each session was guided by a physical therapist. Timed up-and-go and one-leg standing tests were conducted before and after the intervention. [Results] All subjects showed significant improvements in the results of the timed up-and-go test. However, there were no significant changes in the results of the one-leg standing test. [Conclusion] The exercise protocol involving Nintendo with the Balance Board peripheral appears to improve functional dynamic balance in patients with cerebral palsy. However, static functional balance does not improve after 6 weeks of training. PMID:27630446

A Comparative Study of the Effects of Pilates and Latin Dance on Static and Dynamic Balance in Older Adults.

PubMed

Sofianidis, George; Dimitriou, Anna-Maria; Hatzitaki, Vassilia

2017-07-01

The present study was designed to compare the effectiveness of exercise programs with Pilates and Latin dance on older adults' static and dynamic balance. Thirty-two older adults were divided into three groups: Pilates group, Dance group, and Control group. Static and dynamic balance was assessed with following tasks: (a) tandem stance, (b) one-leg stance, and (c) periodic sway with and without metronome guidance. Analysis revealed a significant reduction of the trunk sway amplitude during the tandem stance with eyes closed, reduction in the center of pressure (CoP) displacement during one-leg stance, and increase in the amplitude of trunk oscillation during the sway task for both intervention groups, and reduction in the standard deviation of the CoP displacement during the metronome paced task only for the dance group. The differences in specific balance indices between the two programs suggest some specific adaptations that may provide useful knowledge for the selection of exercises that are better tailored to the needs of the old adult.

Computational Models of Exercise on the Advanced Resistance Exercise Device (ARED)

NASA Technical Reports Server (NTRS)

Newby, Nate; Caldwell, Erin; Scott-Pandorf, Melissa; Peters,Brian; Fincke, Renita; DeWitt, John; Poutz-Snyder, Lori

2011-01-01

Muscle and bone loss remain a concern for crew returning from space flight. The advanced resistance exercise device (ARED) is used for on-orbit resistance exercise to help mitigate these losses. However, characterization of how the ARED loads the body in microgravity has yet to be determined. Computational models allow us to analyze ARED exercise in both 1G and 0G environments. To this end, biomechanical models of the squat, single-leg squat, and deadlift exercise on the ARED have been developed to further investigate bone and muscle forces resulting from the exercises.

Exercise intensity and its impact on relationships between salivary immunoglobulin A, saliva flow rate and plasma cortisol concentration.

PubMed

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

2018-06-01

Salivary secretory immunoglobulin A (sIgA), saliva flow rate and plasma cortisol concentrations have been shown to be influenced by exercise, particularly the intensity exercise is performed at, and circadian variation. The autonomic nervous system partly regulates salivary secretion, but it is not yet known whether cortisol also explains some variation in salivary parameters. Twelve moderately trained male individuals ([Formula: see text] peak legs : 46.2 ± 6.8 mL·kg -1 ·min -1 ) performed three 45-min constant load exercise trials in the morning: arm cranking exercise at 60%[Formula: see text] peak arms ; moderate cycling at 60%[Formula: see text] peak legs ; and easy cycling at 60%[Formula: see text] peak arms . Timed saliva samples and blood samples for plasma cortisol concentration determination were obtained before, post, 2 h post, and 4 h post-exercise. Saliva was collected in an additional resting trial at the same time points. At each time point for each exercise trial, negative correlations between cortisol and saliva flow rate (explaining 25 ± 17% of the variance, R 2  = 0.002-0.46) and positive correlations between cortisol and sIgA concentration (explaining 8 ± 8% of the variance R 2  = 0.002-0.24) were found. Saliva flow rate increased over time, whereas sIgA concentration and cortisol decreased over time for all trials (P < 0.05), there was no effect of time for sIgA secretion rate (P = 0.16). These results show a relationship between cortisol and saliva flow rate, which directly impacts on the concentration of salivary analytes. This study further confirms circadian variations in salivary parameters which must be acknowledged when standardising salivary data collection.

Acute Effects of Two Different Warm-Up Protocols on Flexibility and Lower Limb Explosive Performance in Male and Female High Level Athletes

PubMed Central

Tsolakis, Charilaos; Bogdanis, Gregory C.

2012-01-01

This study examined the effects of two different warm-up protocols on lower limb power and flexibility in high level athletes. Twenty international level fencers (10 males and 10 females) performed two warm-up protocols that included 5-min light jogging and either short (15s) or long (45s) static stretching exercises for each of the main leg muscle groups (quadriceps, hamstrings and triceps surae), followed by either 3 sets of 3 (short stretching treatment), or 3 sets of 5 tuck jumps (long stretching treatment), in a randomized crossover design with one week between treatments. Hip joint flexion was measured with a Lafayette goniometer before and after the 5-min warm-up, after stretching and 8 min after the tuck jumps, while counter movement jump (CMJ) performance was evaluated by an Ergojump contact platform, before and after the stretching treatment, as well as immediately after and 8 minutes after the tuck jumps. Three way ANOVA (condition, time, gender) revealed significant time (p < 0.001) and gender (p < 0.001) main effects for hip joint flexion, with no interaction between factors. Flexibility increased by 6. 8 ± 1.1% (p < 0.01) after warm-up and by another 5.8 ± 1.6% (p < 0.01) after stretching, while it remained increased 8 min after the tuck jumps. Women had greater ROM compared with men at all time points (125 ± 8° vs. 94 ± 4° p<0.01 at baseline), but the pattern of change in hip flexibility was not different between genders. CMJ performance was greater in men compared with women at all time points (38.2 ± 1.9 cm vs. 29.8 ± 1.2 cm p < 0.01 at baseline), but the percentage of change CMJ performance was not different between genders. CMJ performance remained unchanged throughout the short stretching protocol, while it decreased by 5.5 ± 0.9% (p < 0.01) after stretching in the long stretching protocol However, 8 min after the tuck jumps, CMJ performance was not different from the baseline value (p = 0.075). In conclusion, lower limb power may be decreased after long periods of stretching, but performance of explosive exercises may reverse this phenomenon. Key points Stretching of the main leg muscle groups for 45 s results in a relatively large decrease (by 5.5%) in subsequent jumping performance Stretching of the main leg muscle groups for only 15 s results in an increase in flexibility similar to that of the longer duration stretching (by 12.6%), with no change in subsequent jumping performance Performance of a PAP exercise such as tuck jumps may reverse the negative effects of long duration stretching on leg muscle power. However, jumping performance is not increased above baseline Speed/power athletes should be advised against using long duration stretching. The number of repetitions of a PAP exercise such as the tuck jumps, should be further examined in order to induce an increase in explosive performance during competition PMID:24150077

Facing up to the imperceptible perspiration. Modulatory influences by diabetic neuropathy, physical exercise and antiperspirant.

PubMed

Xhauflaire-Uhoda, Emmanuelle; Mayeux, Géraldine; Quatresooz, Pascale; Scheen, André; Piérard, Gérald E

2011-11-01

Sweating is variably altered by physical exercise, diabetic neuropathy and antiperspirants. Skin temperature, skin surface water loss (SSWL), the Corneometer(®) average capacitance (CMAC) and skin capacitance mapping (SCM) were measured before and after moderate physical exercise in 20 healthy subjects. The effect of 5% aluminium chloride hexahydrate (ACH) in a water solution was similarly tested. The same assessments were performed in 20 diabetic patients at rest. Diabetic neuropathy appeared at rest as an increased (compensatory) SCM on the forearms without obvious modification on the hypohidrotic legs. On ACH sites after exercise, SCM revealed both a lowered number of active sweat glands and a lighter stratum corneum (SC) (dryness). In addition, CMAC and SSWL were decreased on ACH sites at rest and at completion of exercise. In diabetic neuropathy, the compensatory hyperhidrosis is more easily disclosed than the hypohidrosis. ACH affects both sweat excretion and the SC hydration. © 2011 John Wiley & Sons A/S.

Application of a Web-Enabled Leg Training System for the Objective Monitoring and Quantitative Analysis of Exercise-Induced Fatigue

PubMed Central

Dedova, Irina V

2016-01-01

Background Sustained cardiac rehabilitation is the key intervention in the prevention and treatment of many human diseases. However, implementation of exercise programs can be challenging because of early fatigability in patients with chronic diseases, overweight individuals, and aged people. Current methods of fatigability assessment are based on subjective self-reporting such as rating of perceived exertion or require specialized laboratory conditions and sophisticated equipment. A practical approach allowing objective measurement of exercise-induced fatigue would be useful for the optimization of sustained delivery of cardiac rehabilitation to improve patient outcomes. Objectives The objective of this study is to develop and validate an innovative approach, allowing for the objective assessment of exercise-induced fatigue using the Web-enabled leg rehabilitation system. Methods MedExercise training devices were equipped with wireless temperature sensors in order to monitor their usage by temperature rise in the resistance unit (Δt°). Since Δt° correlated with the intensity and duration of exercise, this parameter was used to characterize participants’ leg work output (LWO). Personal smart devices such as laptop computers with wireless gateways and relevant software were used for monitoring of self-control training. Connection of smart devices to the Internet and cloud-based software allowed remote monitoring of LWO in participants training at home. Heart rates (HRs) were measured by fingertip pulse oximeters simultaneously with Δt° in 7 healthy volunteers. Results Exercise-induced fatigue manifested as the decline of LWO and/or rising HR, which could be observed in real-time. Conversely, training at the steady-state LWO and HR for the entire duration of exercise bout was considered as fatigue-free. The amounts of recommended daily physical activity were expressed as the individual Δt° values reached during 30-minute fatigue-free exercise of moderate intensity resulting in a mean of 8.1°C (SD 1.5°C, N=7). These Δt° values were applied as the thresholds for sending automatic notifications upon taking the personalized LWO doses by self-control training at home. While the mean time of taking LWO doses was 30.3 (SD 4.1) minutes (n=25), analysis of times required to reach the same Δt° by the same participant revealed that longer durations were due to fatigability, manifesting as reduced LWO at the later stages of training bouts. Typically, exercising in the afternoons associated with no fatigue, although longer durations of evening sessions suggested a diurnal fatigability pattern. Conclusions This pilot study demonstrated the feasibility of objective monitoring of fatigue development in real-time and online as well as retrospective fatigability quantification by the duration of training bouts to reach the same exercise dose. This simple method of leg training at home accompanied by routine fatigue monitoring might be useful for the optimization of exercise interventions in primary care and special populations. PMID:27549345

Metabolic and Cardiovascular Responses to Upright Cycle Exercise with Leg Blood Flow Reduction

PubMed Central

Ozaki, Hayao; Brechue, William F.; Sakamaki, Mikako; Yasuda, Tomohiro; Nishikawa, Masato; Aoki, Norikazu; Ogita, Futoshi; Abe, Takashi

2010-01-01

The purpose of this study was to examine the metabolic and cardiovascular response to exercise without (CON) or with (BFR) restricted blood flow to the muscles. Ten young men performed upright cycle exercise at 20, 40, and 60% of maximal oxygen uptake, VO2max in both conditions while metabolic and cardiovascular parameters were determined. Pre-exercise VO2 was not different between CON and BFR. Cardiac output (Q) was similar between the two conditions as a 25% reduction in stroke volume (SV) observed in BFR was associated with a 23% higher heart rate (HR) in BFR compared to CON. As a result rate-pressure product (RPP) was higher in the BFR but there was no difference in mean arterial pressure (MAP) or total peripheral resistance (TPR). During exercise, VO2 tended to increase with BFR (~10%) at each workload. Q increased in proportion to exercise intensity and there were no differences between conditions. The increase in SV with exercise was impaired during BFR; being ~20% lower in BFR at each workload. Both HR and RPP were significantly greater at each workload with BFR. MAP and TPR were greater with BFR at 40 and 60% VO2max. In conclusion, the BFR employed impairs exercise SV but central cardiovascular function is maintained by an increased HR. BFR appears to result in a greater energy demand during continuous exercise between 20 and 60% of control VO2max; probably indicated by a higher energy supply and RPP. When incorporating BFR, HR and RPP may not be valid or reliable indicators of exercise intensity. Key points Blood flow reduction (BFR) employed impairs stroke volume (SV) during exercise, but central cardiovascular function is maintained by an increased heart rate (HR). BFR appears to result in a greater energy demand during continuous exercise between 20 and 60% of control VO2max; Probably indicated by a higher energy supply (VO2) and rate-pressure product (HR x systolic blood pressure). PMID:24149689

Resistance exercise load does not determine training-mediated hypertrophic gains in young men

PubMed Central

Mitchell, Cameron J.; Churchward-Venne, Tyler A.; West, Daniel W. D.; Burd, Nicholas A.; Breen, Leigh; Baker, Steven K.

2012-01-01

We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 ± 1 yr, 22.6 ± 2.1 kg/m2; means ± SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 ± 1.8%, 80%-1 = 3.2 ± 0.8%, and 80%-3= 7.2 ± 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure. PMID:22518835

Exercise-Associated Collapse in Endurance Events: A Classification System.

ERIC Educational Resources Information Center

Roberts, William O.

1989-01-01

Describes a classification system devised for exercise-associated collapse in endurance events based on casualties observed at six Twin Cities Marathons. Major diagnostic criteria are body temperature and mental status. Management protocol includes fluid and fuel replacement, temperature correction, and leg cramp treatment. (Author/SM)

Ventilatory responses to exercise training in obese adolescents.

PubMed

Mendelson, Monique; Michallet, Anne-Sophie; Estève, François; Perrin, Claudine; Levy, Patrick; Wuyam, Bernard; Flore, Patrice

2012-10-15

The aim of this study was to examine ventilatory responses to training in obese adolescents. We assessed body composition, pulmonary function and ventilatory responses (among which expiratory flow limitation and operational lung volumes) during progressive cycling exercise in 16 obese adolescents (OB) before and after 12 weeks of exercise training and in 16 normal-weight volunteers. As expected, obese adolescents' resting expiratory reserve volume was lower and inversely correlated with thoraco-abdominal fat mass (r = -0.74, p<0.0001). OB presented lower end expiratory (EELV) and end inspiratory lung volumes (EILV) at rest and during submaximal exercise, and modest expiratory flow limitation. After training, OB increased maximal aerobic performance (+19%) and maximal inspiratory pressure (93.7±31.4 vs. 81.9±28.2 cm H2O, +14%) despite lack of decrease in trunk fat and body weight. Furthermore, EELV and EILV were greater during submaximal exercise (+11% and +9% in EELV and EILV, respectively), expiratory flow limitation delayed but was not accompanied by increased V(T). However, submaximal exertional symptoms (dyspnea and leg discomfort) were significantly decreased (-71.3% and -70.7%, respectively). Our results suggest that exercise training can improve pulmonary function at rest (static inspiratory muscle strength) and exercise (greater operating lung volumes and delayed expiratory flow limitation) but these modifications did not entirely account for improved dyspnea and exercise performance in obese adolescents. Copyright © 2012 Elsevier B.V. All rights reserved.

Near-Infrared Monitoring of Model Chronic Compartment Syndrome In Exercising Skeletal Muscle

NASA Technical Reports Server (NTRS)

Hargens, Alan R.; Breit, G. A.; Gross, J. H.; Watenpaugh, D. E.; Chance, B.

1995-01-01

Chronic compartment syndrome (CCS) is characterized by muscle ischemia, usually in the anterior oompartment of the leg, caused by high intramuscular pressure during exercise. Dual-wave near-infrared (NIR) spectroscopy is an optical technique that allows noninvasive tracking of variations in muscle tissue oxygenation (Chance et al., 1988). We hypothesized that with a model CCS, muscle tissue oxygenation will show a greater decline during exercise and a slower recovery post-exercise than under normal conditions.

The re-establishment of the normal blood lactate response to exercise in humans after prolonged acclimatization to altitude

PubMed Central

van Hall, G; Calbet, J A L; Søndergaard, H; Saltin, B

2001-01-01

One to five weeks of chronic exposure to hypoxia has been shown to reduce peak blood lactate concentration compared to acute exposure to hypoxia during exercise, the high altitude ‘lactate paradox’. However, we hypothesize that a sufficiently long exposure to hypoxia would result in a blood lactate and net lactate release from the active leg to an extent similar to that observed in acute hypoxia, independent of work intensity. Six Danish lowlanders (25–26 years) were studied during graded incremental bicycle exercise under four conditions: at sea level breathing either ambient air (0 m normoxia) or a low-oxygen gas mixture (10 % O2 in N2, 0 m acute hypoxia) and after 9 weeks of acclimatization to 5260 m breathing either ambient air (5260 m chronic hypoxia) or a normoxic gas mixture (47 % O2 in N2, 5260 m acute normoxia). In addition, one-leg knee-extensor exercise was performed during 5260 m chronic hypoxia and 5260 m acute normoxia. During incremental bicycle exercise, the arterial lactate concentrations were similar at sub-maximal work at 0 m acute hypoxia and 5260 m chronic hypoxia but higher compared to both 0 m normoxia and 5260 m acute normoxia. However, peak lactate concentration was similar under all conditions (10.0 ± 1.3, 10.7 ± 2.0, 10.9 ± 2.3 and 11.0 ± 1.0 mmol l−1) at 0 m normoxia, 0 m acute hypoxia, 5260 m chronic hypoxia and 5260 m acute normoxia, respectively. Despite a similar lactate concentration at sub-maximal and maximal workload, the net lactate release from the leg was lower during 0 m acute hypoxia (peak 8.4 ± 1.6 mmol min−1) than at 5260 m chronic hypoxia (peak 12.8 ± 2.2 mmol min−1). The same was observed for 0 m normoxia (peak 8.9 ± 2.0 mmol min−1) compared to 5260 m acute normoxia (peak 12.6 ± 3.6 mmol min−1). Exercise after acclimatization with a small muscle mass (one-leg knee-extensor) elicited similar lactate concentrations (peak 4.4 ± 0.2 vs. 3.9 ± 0.3 mmol l−1) and net lactate release (peak 16.4 ± 1.8 vs. 14.3 mmol l−1) from the active leg at 5260 m chronic hypoxia and 5260 m acute normoxia. In conclusion, in lowlanders acclimatized for 9 weeks to an altitude of 5260 m, the arterial lactate concentration was similar at 0 m acute hypoxia and 5260 m chronic hypoxia. The net lactate release from the active leg was higher at 5260 m chronic hypoxia compared to 0 m acute hypoxia, implying an enhanced lactate utilization with prolonged acclimatization to altitude. The present study clearly shows the absence of a lactate paradox in lowlanders sufficiently acclimatized to altitude. PMID:11691888

Application of acute maximal exercise to protect orthostatic tolerance after simulated microgravity

NASA Technical Reports Server (NTRS)

Engelke, K. A.; Doerr, D. F.; Crandall, C. G.; Convertino, V. A.

1996-01-01

We tested the hypothesis that one bout of maximal exercise performed at the conclusion of prolonged simulated microgravity would improve blood pressure stability during an orthostatic challenge. Heart rate (HR), mean arterial blood pressure (MAP), norepinephrine (NE), epinephrine (E), arginine vasopressin (AVP), plasma renin activity (PRA), atrial natriuretic peptide (ANP), cardiac output (Q), forearm vascular resistance (FVR), and changes in leg volume were measured during lower body negative pressure (LBNP) to presyncope in seven subjects immediately prior to reambulation from 16 days of 6 degrees head-down tilt (HDT) under two experimental conditions: 1) after maximal supine cycle ergometry performed 24 h before returning to the upright posture (exercise) and 2) without exercise (control). After HDT, the reduction of LBNP tolerance time from pre-HDT levels was greater (P = 0.041) in the control condition (-2.0 +/- 0.2 min) compared with the exercise condition (-0.4 +/- 0.2 min). At presyncope after HDT, FVR and NE were higher (P < 0.05) after exercise compared with control, whereas MAP, HR, E, AVP, PRA, ANP, and leg volume were similar in both conditions. Plasma volume (PV) and carotid-cardiac baroreflex sensitivity were reduced after control HDT, but were restored by the exercise treatment. Maintenance of orthostatic tolerance by application of acute intense exercise after 16 days of simulated microgravity was associated with greater circulating levels of NE, vasoconstriction, Q, baroreflex sensitivity, and PV.

Changes in Passive Tension of the Hamstring Muscles During a Simulated Soccer Match.

PubMed

Marshall, Paul W; Lovell, Ric; Siegler, Jason C

2016-07-01

Passive muscle tension is increased after damaging eccentric exercise. Hamstring-strain injury is associated with damaging eccentric muscle actions, but no research has examined changes in hamstring passive muscle tension throughout a simulated sport activity. The authors measured hamstring passive tension throughout a 90-min simulated soccer match (SAFT90), including the warm-up period and every 15 min throughout the 90-min simulation. Passive hamstring tension of 15 amateur male soccer players was measured using the instrumented straight-leg-raise test. Absolute torque (Nm) and slope (Nm/°) of the recorded torque-angular position curve were used for data analysis, in addition to total leg range of motion (ROM). Players performed a 15-min prematch warm-up, then performed the SAFT90 including a 15-min halftime rest period. Reductions in passive stiffness of 20-50° of passive hip flexion of 22.1-29.2% (P < .05) were observed after the warm-up period. During the SAFT90, passive tension increased in the latter 20% of the range of motion of 10.1-10.9% (P < .05) concomitant to a 4.5% increase in total hamstring ROM (P = .0009). The findings of this study imply that hamstring passive tension is reduced after an active warm-up that includes dynamic stretching but does not increase in a pattern suggestive of eccentric induced muscle damage during soccer-specific intermittent exercise. Hamstring ROM and passive tension increases are best explained by improved stretch tolerance.

Effects of non-fatiguing respiratory muscle loading induced by expiratory flow limitation during strenuous incremental cycle exercise on metabolic stress and circulating natural killer cells.

PubMed

Rolland-Debord, Camille; Morelot-Panzini, Capucine; Similowski, Thomas; Duranti, Roberto; Laveneziana, Pierantonio

2017-12-01

Exercise induces release of cytokines and increase of circulating natural killers (NK) lymphocyte during strong activation of respiratory muscles. We hypothesised that non-fatiguing respiratory muscle loading during exercise causes an increase in NK cells and in metabolic stress indices. Heart rate (HR), ventilation (VE), oesophageal pressure (Pes), oxygen consumption (VO 2 ), dyspnoea and leg effort were measured in eight healthy humans (five men and three women, average age of 31 ± 4 years and body weight of 68 ± 10 kg), performing an incremental exercise testing on a cycle ergometer under control condition and expiratory flow limitation (FL) achieved by putting a Starling resistor. Blood samples were obtained at baseline, at peak of exercise and at iso-workload corresponding to that reached at the peak of FL exercise during control exercise. Diaphragmatic fatigue was evaluated by measuring the tension time index of the diaphragm. Respiratory muscle overloading caused an earlier interruption of exercise. Diaphragmatic fatigue did not occur in the two conditions. At peak of flow-limited exercise compared to iso-workload, HR, peak inspiratory and expiratory Pes, NK cells and norepinephrine were significantly higher. The number of NK cells was significantly related to ΔPes (i.e. difference between the most and the less negative Pes) and plasmatic catecholamines. Loading of respiratory muscles is able to cause an increase of NK cells provided that activation of respiratory muscles is intense enough to induce a significant metabolic stress.

Insulin and glucose responses during bed rest with isotonic and isometric exercise

NASA Technical Reports Server (NTRS)

Dolkas, C. B.; Greenleaf, J. E.

1977-01-01

The effects of daily intensive isotonic (68% maximum oxygen uptake) and isometric (21% maximum extension force) leg exercise on plasma insulin and glucose responses to an oral glucose tolerance test (OGTT) during 14-day bed-rest (BR) periods were investigated in seven young healthy men. The OGTT was given during ambulatory control and on day 10 of the no-exercise, isotonic, and isometric exercise BR periods during the 15-wk study. The subjects were placed on a controlled diet starting 10 days before each BR period. During BR, basal plasma glucose concentration remained unchanged with no exercise, but increased (P less 0.05) to 87-89 mg/100 ml with both exercise regimens on day 2, and then fell slightly below control levels on day 13. The fall in glucose content during BR was independent of the exercise regimen and was an adjustment for the loss of plasma volume. The intensity of the responses of insulin and glucose to the OGTT was inversely proportional to the total daily energy expenditure during BR. It was estimated that at least 1020 kcal/day must be provided by supplemental exercise to restore the hyperinsulinemia to control levels.

Conduit Artery Diameter During Exercise Is Enhanced After Local, but Not Remote, Ischemic Preconditioning

PubMed Central

Cocking, Scott; Cable, N. T.; Wilson, Mathew G.; Green, Daniel J.; Thijssen, Dick H. J.; Jones, Helen

2018-01-01

Introduction: The ability of ischemic preconditioning (IPC) to enhance exercise capacity may be mediated through altering exercise-induced blood flow and/or vascular function. This study investigated the hypothesis that (local) IPC enhances exercise-induced blood flow responses and prevents decreases in vascular function following exercise. Methods: Eighteen healthy, recreationally trained, male participants (mean ±SD: age 32 ± 8 years; BMI 24.2 ± 2.3; blood pressure 122 ± 10/72 ± 8 mmHg; resting HR 58 ± 9 beats min-1) received IPC (220 mmHg; 4 × 5-min bilateral arms), REMOTE IPC (220 mmHg; 4 × 5-min bilateral legs), or SHAM (20 mmHg; 4 × 5-min bilateral arms) in a counterbalanced order prior to 30-min of submaximal (25% maximal voluntary contraction) unilateral rhythmic handgrip exercise. Brachial artery diameter and blood flow were assessed every 5-min throughout the 30-min submaximal exercise using high resolution ultrasonography. Pre- and post-exercise vascular function was measured using flow-mediated dilation (FMD). Results: IPC resulted in enlarged brachial artery diameter during exercise [0.016 cm (0.003–0.03 cm), P = 0.015] compared to REMOTE IPC, but blood flow during exercise was similar between conditions (P > 0.05). Blood flow (l/min) increased throughout exercise (time: P < 0.005), but there was no main effect of condition (P = 0.29) or condition ∗ time interaction (P = 0.83). Post-exercise FMD was similar between conditions (P > 0.05). Conclusion: Our data show that local (but not remote) IPC, performed as a strategy prior to exercise, enhanced exercise-induced conduit artery diameter dilation, but these changes do not translate into increased blood flow during exercise nor impact post-exercise vascular function. PMID:29740345

Muscle damage induced by stretch-shortening cycle exercise.

PubMed

Kyröläinen, H; Takala, T E; Komi, P V

1998-03-01

Strenuous stretch-shortening cycle exercise was used as a model to study the leakage of proteins from skeletal muscle. The analysis included serum levels of creatine kinase (S-CK), myoglobin (S-Mb), and carbonic anhydrase (S-CA III). Blood samples from power- (N=11) and endurance-trained (N=10) athletes were collected before, 0, and 2 h after the exercise, which consisted of a total of 400 jumps. The levels of all determined myocellular proteins increased immediately after the exercise (P < 0.05-0.001) among both subject groups. In the endurance group, the protein levels increased (P < 0.05-0.001) further during the following 2 h after the exercise, and the ratio of S-CA III and S-Mb decreased (P < 0.05) in a before-after comparison. This was not the case among the power group despite their greater mechanical work (P < 0.001) and higher ratio of eccentric and concentric EMG activity of the leg extensor muscles (P < 0.05). The differences of the determined protein levels between the subject groups might be due to obvious differences in the muscle fiber distribution, differences in recruitment order of motor units, and/or differences in training background.

Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training.

PubMed

Roberts, Llion A; Raastad, Truls; Markworth, James F; Figueiredo, Vandre C; Egner, Ingrid M; Shield, Anthony; Cameron-Smith, David; Coombes, Jeff S; Peake, Jonathan M

2015-09-15

We investigated functional, morphological and molecular adaptations to strength training exercise and cold water immersion (CWI) through two separate studies. In one study, 21 physically active men strength trained for 12 weeks (2 days per week), with either 10 min of CWI or active recovery (ACT) after each training session. Strength and muscle mass increased more in the ACT group than in the CWI group (P < 0.05). Isokinetic work (19%), type II muscle fibre cross-sectional area (17%) and the number of myonuclei per fibre (26%) increased in the ACT group (all P < 0.05), but not the CWI group. In another study, nine active men performed a bout of single-leg strength exercises on separate days, followed by CWI or ACT. Muscle biopsies were collected before and 2, 24 and 48 h after exercise. The number of satellite cells expressing neural cell adhesion molecule (NCAM) (10-30%) and paired box protein (Pax7) (20-50%) increased 24-48 h after exercise with ACT. The number of NCAM(+) satellite cells increased 48 h after exercise with CWI. NCAM(+) - and Pax7(+) -positive satellite cell numbers were greater after ACT than after CWI (P < 0.05). Phosphorylation of p70S6 kinase(Thr421/Ser424) increased after exercise in both conditions but was greater after ACT (P < 0.05). These data suggest that CWI attenuates the acute changes in satellite cell numbers and activity of kinases that regulate muscle hypertrophy, which may translate to smaller long-term training gains in muscle strength and hypertrophy. The use of CWI as a regular post-exercise recovery strategy should be reconsidered. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

Influence of supplementation with branched-chain amino acids in combination with resistance exercise on p70S6 kinase phosphorylation in resting and exercising human skeletal muscle.

PubMed

Apró, W; Blomstrand, E

2010-11-01

Skeletal muscle growth is thought to be regulated by the mammalian target of rapamycin (mTOR) pathway, which can be activated by resistance exercise and branched-chain amino acids (BCAA). The major aim of the present study was to distinguish between the influence of resistance exercise and BCAA on key enzymes considered to be involved in the regulation of protein synthesis, including p70(S6) kinase (p70(S6k)). Nine healthy subjects (four men and five women) performed unilateral resistance exercise on two occasions separated by 1 month. Subjects were randomly supplied either a mixture of BCAA or flavoured water. Muscle biopsies were taken from both resting and exercising muscle before, after and 1 h after exercise. Phosphorylation of Akt was unaltered by either resistance exercise and/or BCAA supplementation whereas mTOR phosphorylation was enhanced (P<0.05) to a similar extent in both exercising and resting muscle following exercise in the absence (70-90%) and presence of BCAA supplementation (80-130%). Phosphorylation of p70(S6k) was unaffected by resistance exercise alone; however, BCAA intake increased (P<0.05) this phosphorylation in both legs following exercise. In resting muscle, a 5- and 16-fold increase in p70(S6k) was observed immediately after and 1 h after exercise, respectively, as compared to 11- and 30-fold increases in the exercising muscle. Phosphorylation of eukaryotic elongation factor 2 was attenuated 1 h after exercise (P<0.05) in both resting (10-40%) and exercising muscle (30-50%) under both conditions. The present findings indicate that resistance exercise and BCAA exert both separate and combined effects on the p70(S6k) phosphorylation in an Akt-independent manner. © 2010 The Authors. Journal compilation © 2010 Scandinavian Physiological Society.

Differentiated Ratings of Perceived Exertion during Physical Exercise

DTIC Science & Technology

1982-01-01

the threshold Differentiated perceptions of exertion: part I. Mode of integration of anaerobic work. Int. Z. angew. Physiol. 27:311-328, 1969. of...a. (41) anaerobic metabolites Pandoll & Noble (43) se tiMs from muscles, joints, tendM Stamford & Noble (SO)* muscle temperature, mu lactate, EK pror...from a marathon run. Med. Set. leading to increased effort, leg fatigue, and respiratory distress during Sports 11:239-243, 1979. prolonged, strenuous

Rehabilitation of children and infants with osteogenesis imperfecta. A program for ambulation.

PubMed

Gerber, L H; Binder, H; Weintrob, J; Grange, D K; Shapiro, J; Fromherz, W; Berry, R; Conway, A; Nason, S; Marini, J

1990-02-01

Management of children and infants with osteogenesis imperfecta (OI) poses difficult decisions for pediatricians, orthopedists, and physiatrists. These children are frequently frail with disabling bone and joint deformities and fractures. In an eight-year cumulative management of 12 children with OI, a comprehensive program included strengthening exercises to the pelvic girdle and lower extremity muscles, in addition to pool exercises and molded seating to support upright posture. Long leg braces were fitted when the children were able to sit unsupported. All 12 were fitted with braces; nine were functional ambulators, and three were home ambulators. Six children required femoral plating or rodding, two of whom subsequently had the metal removed. Lower extremity fractures averaged one and one-half per year prior to bracing for nine children who had fractures. There was 0.83 fracture per year for the ten children who had fractures after bracing. The degree of femoral bowing increased in four, decreased in four, and remained unchanged in four, while the degree of tibial bowing increased in two, decreased in nine, and remained unchanged in one during the observation period. A comprehensive rehabilitation program and long leg bracing with surgical operations on the femur result in a high level of functional activity for children with OI with an acceptable level of risk for fracture.

Transfer of strength and power training to sports performance.

PubMed

Young, Warren B

2006-06-01

The purposes of this review are to identify the factors that contribute to the transference of strength and power training to sports performance and to provide resistance-training guidelines. Using sprinting performance as an example, exercises involving bilateral contractions of the leg muscles resulting in vertical movement, such as squats and jump squats, have minimal transfer to performance. However, plyometric training, including unilateral exercises and horizontal movement of the whole body, elicits significant increases in sprint acceleration performance, thus highlighting the importance of movement pattern and contraction velocity specificity. Relatively large gains in power output in nonspecific movements (intramuscular coordination) can be accompanied by small changes in sprint performance. Research on neural adaptations to resistance training indicates that intermuscular coordination is an important component in achieving transfer to sports skills. Although the specificity of resistance training is important, general strength training is potentially useful for the purposes of increasing body mass, decreasing the risk of soft-tissue injuries, and developing core stability. Hypertrophy and general power exercises can enhance sports performance, but optimal transfer from training also requires a specific exercise program.

Influence of a preventive training program on lower limb kinematics and vertical jump height of male volleyball athletes.

PubMed

Leporace, Gustavo; Praxedes, Jomilto; Pereira, Glauber Ribeiro; Pinto, Sérgio Medeiros; Chagas, Daniel; Metsavaht, Leonardo; Chame, Flávio; Batista, Luiz Alberto

2013-02-01

To examine the influence of a preventative training program (PTP) on sagittal plane kinematics during different landing tasks and vertical jump height (VJH) in males. Six weeks prospective exercise intervention. Fifteen male volleyball athletes (13 ± 0.7 years, 1.70 ± 0.12 m, 60 ± 12 kg). PTP consisting of plyometric, balance and core stability exercises three times per week for six weeks. Bilateral vertical jumps with double leg (DL) and single leg (SL) landings were performed to measure the effects of training. Kinematics of the knee and hip before and after training and VJH attained during both tasks after training. The hypothesis was that the PTP would produce improvements in VJH, but would not generate great changes in biomechanical behavior. The only change identified for the SL was the longest duration of landing, which represents the time spent from initial ground contact to maximum knee flexion, after training, while increased angular displacement of the knee was observed during DL. The training did not significantly alter the VJH in either the SL (difference: 2.7 cm) or the DL conditions (difference: 3.5 cm). Despite the PTP's effectiveness in inducing some changes in kinematics, the changes were specific for each task, which highlights the importance of the specificity and individuality in selecting prevention injury exercises. Despite the absence of significant increases in the VJH, the absolute differences after training showed increases corroborating with the findings of statistically powerful studies that compared the results with control groups. The results suggest that short-term PTPs in low risk young male volleyball athletes may enhance performance and induce changes in some kinematic parameters. Copyright © 2012 Elsevier Ltd. All rights reserved.

Large strengthening effect of a hip-flexor training programme: a randomized controlled trial.

PubMed

Thorborg, Kristian; Bandholm, Thomas; Zebis, Mette; Andersen, Lars Louis; Jensen, Jesper; Hölmich, Per

2016-07-01

To investigate the effect on hip-flexion strength of a 6-week hip-flexor training programme using elastic bands as resistance. We hypothesized that the training group, compared to a control group, would increase their hip-flexion strength more. Thirty-three healthy subjects (45 % females), 24(5) years of age, were included in a randomized controlled trial and allocated to heavy strength training of the hip-flexor muscles or to control (no strength training). Strength training of the hip-flexors (dominant leg) was performed three times 10 min per week for 6 weeks. The strength training group progressed from 15 repetition maximum (RM) (week 1) to 8 RM (week 6). Isometric hip-flexion strength (primary outcome) was measured by a blinded assessor using a reliable test procedure. In the strength training group, the isometric hip-flexion strength of the trained leg increased by 17 %, (p < 0.001). The between-group difference in hip-flexion strength change in the trained leg (dominant leg, training group) versus the non-trained leg (dominant leg, control group) was significantly different from baseline to follow-up, corresponding to a mean change of 0.34 (95 % CI 0.17-0.52) Nm/kg, in favour of the strength training group (p < 0.001). Simple hip-flexor strength training using elastic bands as external loading, for only 6 weeks, substantially improves hip-flexor muscle strength. This simple exercise programme seems promising for future prevention and treatment of acute and longstanding hip-flexor injuries, such as acute rectus femoris injuries and longstanding iliopsoas-related pain and impingement. I.

Knee-joint proprioception during 30-day 6 degrees head-down bed rest with isotonic and isokinetic exercise training

NASA Technical Reports Server (NTRS)

Bernauer, E. M.; Walby, W. F.; Ertl, A. C.; Dempster, P. T.; Bond, M.; Greenleaf, J. E.

1994-01-01

To determine if daily isotonic exercise or isokinetic exercise training coupled with daily leg proprioceptive training, would influence leg proprioceptive tracking responses during bed rest (BR), 19 men (36 +/- SD 4 years, 178 +/- 7 cm, 76.8 +/- 7.8 kg) were allocated into a no-exercise (NOE) training control group (n = 5), and isotonic exercise (ITE, n = 7) and isokinetic exercise (IKE, n = 7) training groups. Exercise training was conducted during BR for two 30-min periods.d-1, 5 d.week-1. Only the IKE group performed proprioceptive training using a new isokinetic procedure with each lower extremity for 2.5 min before and after the daily exercise training sessions; proprioceptive testing occurred weekly for all groups. There were no significant differences in proprioceptive tracking scores, expressed as a percentage of the perfect score of 100, in the pre-BR ambulatory control period between the three groups. Knee extension and flexion tracking responses were unchanged with NOE during BR, but were significantly greater (*p < 0.05) at the end of BR in both exercise groups when compared with NOE responses (extension: NOE 80.7 +/- 0.7%, ITE 82.9* +/- 0.6%, IKE 86.5* +/- 0.7%; flexion: NOE 77.6 +/- 1.5%, ITE 80.0 +/- 0.8% (NS), IKE 83.6* +/- 0.8%). Although proprioceptive tracking was unchanged during BR with NOE, both isotonic exercise training (without additional proprioceptive training) and especially isokinetic exercise training when combined with daily proprioceptive training, significantly improved knee proprioceptive tracking responses after 30 d of BR.

Knee-joint proprioception during 30-day 6 degrees head-down bed rest with isotonic and isokinetic exercise training.

PubMed

Bernauer, E M; Walby, W F; Ertl, A C; Dempster, P T; Bond, M; Greenleaf, J E

1994-12-01

To determine if daily isotonic exercise or isokinetic exercise training coupled with daily leg proprioceptive training, would influence leg proprioceptive tracking responses during bed rest (BR), 19 men (36 +/- SD 4 years, 178 +/- 7 cm, 76.8 +/- 7.8 kg) were allocated into a no-exercise (NOE) training control group (n = 5), and isotonic exercise (ITE, n = 7) and isokinetic exercise (IKE, n = 7) training groups. Exercise training was conducted during BR for two 30-min periods.d-1, 5 d.week-1. Only the IKE group performed proprioceptive training using a new isokinetic procedure with each lower extremity for 2.5 min before and after the daily exercise training sessions; proprioceptive testing occurred weekly for all groups. There were no significant differences in proprioceptive tracking scores, expressed as a percentage of the perfect score of 100, in the pre-BR ambulatory control period between the three groups. Knee extension and flexion tracking responses were unchanged with NOE during BR, but were significantly greater (*p < 0.05) at the end of BR in both exercise groups when compared with NOE responses (extension: NOE 80.7 +/- 0.7%, ITE 82.9* +/- 0.6%, IKE 86.5* +/- 0.7%; flexion: NOE 77.6 +/- 1.5%, ITE 80.0 +/- 0.8% (NS), IKE 83.6* +/- 0.8%). Although proprioceptive tracking was unchanged during BR with NOE, both isotonic exercise training (without additional proprioceptive training) and especially isokinetic exercise training when combined with daily proprioceptive training, significantly improved knee proprioceptive tracking responses after 30 d of BR.

Comparison of gluteal and hamstring activation during five commonly used plyometric exercises.

PubMed

Struminger, Aaron H; Lewek, Michael D; Goto, Shiho; Hibberd, Elizabeth; Blackburn, J Troy

2013-08-01

Anterior cruciate ligament injuries occur frequently in athletics, and anterior cruciate ligament injury prevention programs may decrease injury risk. However, previous prevention programs that include plyometrics use a variety of exercises with little justification of exercise inclusion. Because gluteal and hamstring activation is thought to be important for preventing knee injuries, the purpose of this study was to determine which commonly used plyometric exercises produce the greatest activation of the gluteals and hamstrings. EMG (Electromyography) amplitudes of the hamstring and gluteal muscles during preparatory and loading phases of landing were recorded in 41 subjects during 5 commonly used plyometric exercises. Repeated measures ANOVAs (Analysis of Variance) were used on 36 subjects to examine differences in muscle activation. Differences in hamstring (P<.01) and gluteal (P<.01) activities were identified across exercises during the preparatory and landing phases. The single-leg sagittal plane hurdle hops produced the greatest gluteal and hamstring activity in both phases. The 180° jumps did not produce significantly greater gluteal or hamstring activity than any other exercise. Single-leg sagittal plane hurdle hops may be the most effective exercise to activate the gluteals and hamstrings and may be important to include in anterior cruciate ligament injury prevention programs, given the importance of these muscles for limiting valgus loading of the knee. Because 180° jumps do not produce greater gluteal and hamstring activation than other plyometric exercises, their removal from injury prevention programs may be warranted without affecting program efficacy. © 2013.

The effects of balance and postural stability exercises on spa based rehabilitation programme in patients with ankylosing spondylitis.

PubMed

Gunay, Selim M; Keser, Ilke; Bicer, Zemzem T

2018-01-01

Ankylosing spondylitis (AS) can cause severe functional disorders that lead to loss of balance. The aim of this study was to investigate the effects of balance and postural stability exercises on spa based rehabilitation programme in AS subjects. Twenty-one participants were randomized to the study (n= 11) and control groups (n= 10). Patients balance and stability were assessed with the Berg Balance Scale (BBS), Timed Up and Go (TUG) Test, Single Leg Stance Test (SLST) and Functional Reach Test (FRT). AS spesicied measures were used for assessing to other parameters. The treatment plan for both groups consisted of conventional transcutaneous electrical nerve stimulation (TENS), spa and land-based exercises 5 days per week for 3 weeks. The study group performed exercises based on postural stability and balance with routine physiotherapy practice in thermal water and in exercise room. The TUG, SLST and FUT scores were significantly increased in the study group. In both groups, the BASMI, BASFI, BASDAI and ASQoL scores decreased significantly by the end of the treatment period (p< 0.05). In AS rehabilitation, performing balance and stability exercises in addition to spa based routine approaches can increase the duration of maintaining balance and can improve the benefits of physiotherapy.

Exercise and sports science Australia (ESSA) position statement on exercise and spinal cord injury.

PubMed

Tweedy, Sean M; Beckman, Emma M; Geraghty, Timothy J; Theisen, Daniel; Perret, Claudio; Harvey, Lisa A; Vanlandewijck, Yves C

2017-02-01

Traumatic spinal cord injury (SCI) may result in tetraplegia (motor and/or sensory nervous system impairment of the arms, trunk and legs) or paraplegia (motor and/or sensory impairment of the trunk and/or legs only). The adverse effects of SCI on health, fitness and functioning are frequently compounded by profoundly sedentary behaviour. People with paraplegia (PP) and tetraplegia (TP) have reduced exercise capacity due to paralysis/paresis and reduced exercising stroke volume. TP often further reduces exercise capacity due to lower maximum heart-rate and respiratory function. There is strong, consistent evidence that exercise can improve cardiorespiratory fitness and muscular strength in people with SCI. There is emerging evidence for a range of other exercise benefits, including reduced risk of cardio-metabolic disease, depression and shoulder pain, as well as improved respiratory function, quality-of-life and functional independence. Exercise recommendations for people with SCI are: ≥30min of moderate aerobic exercise on ≥5d/week or ≥20min of vigorous aerobic ≥3d/week; strength training on ≥2d/week, including scapula stabilisers and posterior shoulder girdle; and ≥2d/week flexibility training, including shoulder internal and external rotators. These recommendations may be aspirational for profoundly inactive clients and stratification into "beginning", "intermediate" and "advanced" will assist application of the recommendations in clinical practice. Flexibility exercise is recommended to preserve upper limb function but may not prevent contracture. For people with TP, Rating of Perceived Exertion may provide a more valid indication of exercise intensity than heart rate. The safety and effectiveness of exercise interventions can be enhanced by initial screening for autonomic dysreflexia, orthostatic hypotension, exercise-induced hypotension, thermoregulatory dysfunction, pressure sores, spasticity and pain. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Metabolic Cost of Stride Rate, Resistance, and Combined Use of Arms and Legs on the Elliptical Trainer

ERIC Educational Resources Information Center

Mier, Constance M.; Feito, Yuri

2006-01-01

We measured the effects of stride rate, resistance, and combined arm-leg use on energy expenditure during elliptical trainer exercise and assessed the accuracy of the manufacturer's energy expenditure calculations. Twenty-six men and women (M age = 29 years, SD = 8; M body weight = 73.0 kg, SD = 15.2) participated. Twenty-two participants…

Aerobic exercise improves gastrointestinal motility in psychiatric inpatients

PubMed Central

Kim, Yeon Soo; Song, Bong Kil; Oh, Ji Sun; Woo, Seung Seok

2014-01-01

AIM: To evaluate the benefit of aerobic exercise on colonic transit time (CTT) for psychiatric inpatients in a closed ward. METHODS: Sixty consecutive adult inpatients of the Somang Hospital Psychiatry Unit (Eumsung-gun, South Korea), without CTT-related diseases or drug therapies, were recruited for study from March to June of 2012. Upon enrollment, the patients were randomly assigned to partake in a 12-wk instructor-led group aerobic exercise program (exercise group; n = 30) or to maintain their ordinary daily activities (control group; n = 30). The exercise program was structured as 10 min warm-up (stretching), 40 min exercise, and 10 min cool-down (stretching) for three days each week. The exercise sessions consisted of walking only in week one and aerobics from weeks two to 12, with increasing intensity (50% heart rate reserve (HRR) for weeks one to four, 60% HRR for weeks five to eight, and 70% HRR for weeks nine to 12). CTT was measured before (baseline) and after (week 12) the exercise program, in duplicate (on days four and seven), using abdominal radiography and the multiple radio-opaque marker technique. Changes in the exercising patients’ CTT and weight-, cardiovascular- and fitness-related parameters were statistically assessed. RESULTS: The study dropout rate was 30.0%, with 23 patients in the exercise group and 19 patients in the control group completing the study. At week 12, the exercise group showed decreases in body weight (mean ± SE) baseline: 69.4 ± 2.8 vs study-end: 67.6 ± 2.7; P < 0.635) and body mass index (BMI) (25.2 ± 1.1 vs 24.9 ± 0.8; P < 0.810), but the extent of change was not significantly different from that experienced by the control group (body weight: 68.8 ± 4.0 vs 68.8 ± 3.9; BMI: 24.3 ± 1.1 vs 24.4 ± 1.2). However, the exercise group showed significant improvements in leg muscle strength (baseline: 41.7 ± 4.3 vs study-end: 64.1 ± 5.0; P < 0.001), cardio-respiratory endurance (120.5 ± 4.5 vs 105.4 ± 2.8; P < 0.004), and leg muscle elasticity and power output (21.5 ± 2.6 vs 30.6 ± 2.8; P < 0.001). The exercise group showed an exercise-induced reduction in total CTT (baseline: 54.2 ± 8.0 vs 30.3 ± 6.1), which was significantly different from that experienced by the control group over the 12-wk period (48.6 ± 9.3 vs 48.3 ± 12.3; P = 0.027); however, the exercise-induced decreases in CTT involving the three colonic segments examined (right, left and recto-sigmoid) showed no significant differences from the control group. CONCLUSION: A 12-wk aerobic exercise program can benefit psychiatric inpatients by increasing intestinal motility, possibly decreasing risk of metabolic- and cardiovascular-related disease. PMID:25132778

Aerobic exercise improves gastrointestinal motility in psychiatric inpatients.

PubMed

Kim, Yeon Soo; Song, Bong Kil; Oh, Ji Sun; Woo, Seung Seok

2014-08-14

To evaluate the benefit of aerobic exercise on colonic transit time (CTT) for psychiatric inpatients in a closed ward. Sixty consecutive adult inpatients of the Somang Hospital Psychiatry Unit (Eumsung-gun, South Korea), without CTT-related diseases or drug therapies, were recruited for study from March to June of 2012. Upon enrollment, the patients were randomly assigned to partake in a 12-wk instructor-led group aerobic exercise program (exercise group; n = 30) or to maintain their ordinary daily activities (control group; n = 30). The exercise program was structured as 10 min warm-up (stretching), 40 min exercise, and 10 min cool-down (stretching) for three days each week. The exercise sessions consisted of walking only in week one and aerobics from weeks two to 12, with increasing intensity (50% heart rate reserve (HRR) for weeks one to four, 60% HRR for weeks five to eight, and 70% HRR for weeks nine to 12). CTT was measured before (baseline) and after (week 12) the exercise program, in duplicate (on days four and seven), using abdominal radiography and the multiple radio-opaque marker technique. Changes in the exercising patients' CTT and weight-, cardiovascular- and fitness-related parameters were statistically assessed. The study dropout rate was 30.0%, with 23 patients in the exercise group and 19 patients in the control group completing the study. At week 12, the exercise group showed decreases in body weight (mean ± SE) baseline: 69.4 ± 2.8 vs study-end: 67.6 ± 2.7; P < 0.635) and body mass index (BMI) (25.2 ± 1.1 vs 24.9 ± 0.8; P < 0.810), but the extent of change was not significantly different from that experienced by the control group (body weight: 68.8 ± 4.0 vs 68.8 ± 3.9; BMI: 24.3 ± 1.1 vs 24.4 ± 1.2). However, the exercise group showed significant improvements in leg muscle strength (baseline: 41.7 ± 4.3 vs study-end: 64.1 ± 5.0; P < 0.001), cardio-respiratory endurance (120.5 ± 4.5 vs 105.4 ± 2.8; P < 0.004), and leg muscle elasticity and power output (21.5 ± 2.6 vs 30.6 ± 2.8; P < 0.001). The exercise group showed an exercise-induced reduction in total CTT (baseline: 54.2 ± 8.0 vs 30.3 ± 6.1), which was significantly different from that experienced by the control group over the 12-wk period (48.6 ± 9.3 vs 48.3 ± 12.3; P = 0.027); however, the exercise-induced decreases in CTT involving the three colonic segments examined (right, left and recto-sigmoid) showed no significant differences from the control group. A 12-wk aerobic exercise program can benefit psychiatric inpatients by increasing intestinal motility, possibly decreasing risk of metabolic- and cardiovascular-related disease.

Select Skeletal Muscle mRNAs Related to Exercise Adaptation Are Minimally Affected by Different Pre-exercise Meals that Differ in Macronutrient Profile.

PubMed

Knuiman, Pim; Hopman, Maria T E; Wouters, Jeroen A; Mensink, Marco

2018-01-01

Background: Substantial research has been done on the impact of carbohydrate and fat availability on endurance exercise adaptation, though its role in the acute adaptive response to resistance exercise has yet to be fully characterized. Purpose: We aimed to assess the effects of a pre-resistance exercise isocaloric mixed meal containing different amounts of carbohydrates and fat, on post-resistance exercise gene expression associated with muscle adaptation. Methods: Thirteen young (age 21.2 ± 1.6 year), recreationally trained (VO 2max 51.3 ± 4.8 ml/kg/min) men undertook an aerobic exercise session of 90-min continuous cycling (70% VO 2max ) in the morning with pre- and post-exercise protein ingestion (10 and 15 g casein in a 500 ml beverage pre- and post-exercise, respectively). Subjects then rested for 2 h and were provided with a meal consisting of either 3207 kJ; 52 g protein; 51 g fat; and 23 g carbohydrate (FAT) or 3124 kJ; 53 g protein; 9 g fat; and 109 g carbohydrate (CHO). Two hours after the meal, subjects completed 5 × 8 repetitions (80% 1-RM) for both bilateral leg press and leg extension directly followed by 25 g of whey protein (500 ml beverage). Muscle biopsies were obtained from the vastus lateralis at baseline (morning) and 1 and 3 h post-resistance exercise (afternoon) to determine intramuscular mRNA response. Results: Muscle glycogen levels were significantly decreased post-resistance exercise, without any differences between conditions. Plasma free fatty acids increased significantly after the mixed meal in the FAT condition, while glucose and insulin were higher in the CHO condition. However, PDK4 mRNA quantity was significantly higher in the FAT condition at 3 h post-resistance exercise compared to CHO. HBEGF, INSIG1, MAFbx, MURF1, SIRT1, and myostatin responded solely as a result of exercise without any differences between the CHO and FAT group. FOXO3A, IGF-1, PGC-1α, and VCP expression levels remained unchanged over the course of the day. Conclusion: We conclude that mRNA quantity associated with muscle adaptation after resistance exercise is not affected by a difference in pre-exercise nutrient availability. PDK4 was differentially expressed between CHO and FAT groups, suggesting a potential shift toward fat oxidation and reduced glucose oxidation in the FAT group.

Interventions to enhance patient compliance with leg ulcer treatment: a review of the literature.

PubMed

Van Hecke, Ann; Grypdonck, Maria; Defloor, Tom

2008-01-01

Non-compliance with compression therapy and with leg exercises and leg elevation is a common problem, often reported in patients with venous leg ulceration. Studies on compliance-enhancing interventions and the effectiveness of these interventions in patients with venous leg ulceration were reviewed. MEDLINE, Cochrane, Embase and CINAHL were explored up to April 2005. Reference lists, wound care journals and conference proceedings were searched. Experts and manufacturers of compression systems were contacted. Studies were eligible if they included patients with venous or mixed leg ulcers and reported patient compliance outcome. Twenty studies were included. Most studies describe patient compliance as the extent to which the compression system was worn and/or the extent to which treatment regimen was followed. Self-reporting was the most commonly used method of compliance assessment. There are indications that class III stockings for patients with venous ulcers enhance compliance compared with short stretch compression bandages. No real evidence is found that intermittent pneumatic compression systems improved compliance. There is no well-documented evidence that healthcare system interventions increase compliance. Educational programmes combining cognitive, behavioural and affective components were shown to have a positive effect on leg elevation, but not on compliance with compression therapy. The included studies have a lack of consistency in defining the standard and operationalization of compliance. Patient compliance plays an ancillary role in research. No study has been able to offer an acceptable and well-documented solution to the non-compliance problem. Research might focus on the development of comprehensive compliance-enhancing strategies. A stronger commitment of healthcare providers and society is needed to make progress in this area. The scope of nursing must be expanded to also include the problems experienced by patients with leg ulcers and the improvement of patient compliance.

Cardiorespiratory demand of acute voluntary cycling with functional electrical stimulation in individuals with multiple sclerosis with severe mobility impairment.

PubMed

Edwards, Thomas; Motl, Robert W; Pilutti, Lara A

2018-01-01

Exercise training is one strategy for improving cardiorespiratory fitness (CRF) in multiple sclerosis (MS); however, few modalities are accessible for those with severe mobility impairment. Functional electrical stimulation (FES) cycling is an adapted exercise modality with the potential for improving CRF in people with severe MS. The objective of this study was to characterize the cardiorespiratory response of acute voluntary cycling with FES in people with MS with severe mobility impairment, and to compare this response to passive leg cycling. Eleven participants with MS that required assistance for ambulation completed a single bout of voluntary cycling with FES or passive leg cycling. Oxygen consumption, heart rate (HR), work rate (WR), and ratings of perceived exertion (RPE) were recorded throughout the session. For the FES group, mean exercising oxygen consumption was 8.7 ± 1.8 mL/(kg·min) -1 , or 63.5% of peak oxygen consumption. Mean HR was 102 ± 9.7 bpm, approximately 76.4% of peak HR. Mean WR was 27.0 ± 9.2 W, or 57.3% of peak WR, and median RPE was 13.5 (interquartile range = 5.5). Active cycling with FES was significantly (p < 0.05) more intense than passive leg cycling based on oxygen consumption, HR, WR, and RPE during exercise. In conclusion, voluntary cycling with FES elicited an acute response that corresponded with moderate-to vigorous-intensity activity, suggesting that active cycling with FES can elicit a sufficient stimulus for improving CRF.

Energy Metabolism during Repeated Sets of Leg Press Exercise Leading to Failure or Not

PubMed Central

Gorostiaga, Esteban M.; Navarro-Amézqueta, Ion; Calbet, José A. L.; Hellsten, Ylva; Cusso, Roser; Guerrero, Mario; Granados, Cristina; González-Izal, Miriam; Ibañez, Javier; Izquierdo, Mikel

2012-01-01

This investigation examined the influence of the number of repetitions per set on power output and muscle metabolism during leg press exercise. Six trained men (age 34±6 yr) randomly performed either 5 sets of 10 repetitions (10REP), or 10 sets of 5 repetitions (5REP) of bilateral leg press exercise, with the same initial load and rest intervals between sets. Muscle biopsies (vastus lateralis) were taken before the first set, and after the first and the final sets. Compared with 5REP, 10REP resulted in a markedly greater decrease (P<0.05) of the power output, muscle PCr and ATP content, and markedly higher (P<0.05) levels of muscle lactate and IMP. Significant correlations (P<0.01) were observed between changes in muscle PCr and muscle lactate (R2 = 0.46), between changes in muscle PCr and IMP (R2 = 0.44) as well as between changes in power output and changes in muscle ATP (R2 = 0.59) and lactate (R2 = 0.64) levels. Reducing the number of repetitions per set by 50% causes a lower disruption to the energy balance in the muscle. The correlations suggest that the changes in PCr and muscle lactate mainly occur simultaneously during exercise, whereas IMP only accumulates when PCr levels are low. The decrease in ATP stores may contribute to fatigue. PMID:22808209

Clinical Model of Exercise-Related Dyspnea in Adult Patients With Cystic Fibrosis.

PubMed

Stevens, Daniel; Neyedli, Heather F

2018-05-01

Dyspnea is a highly distressing symptom of pulmonary disease that can make performing physical activities challenging. However, little is known regarding the strongest predictors of exercise-related dyspnea in adult cystic fibrosis (CF). Therefore, the purpose of the present study was to determine the best clinical model of exercise-related dyspnea in this patient group. A retrospective analysis of pulmonary function and cardiopulmonary exercise testing data from patients with CF being followed up at the Adult CF Program at St Michael's Hospital, Toronto, Canada, from 2002 to 2008 were used for the analysis. Patients (n = 88) were male 66%; aged 30.4 ± 9.4 years; body mass index (BMI) 23.1 ± 3.3 kg/m; forced expiratory volume in 1 second (FEV1) 70% ± 19% predicted; and peak oxygen uptake 74% ± 20% predicted. A multivariate linear regression model assessing the effects of age, sex, BMI, airway obstruction (FEV1), perceived muscular leg fatigue, and dynamic hyperinflation explained 54% of the variance in dyspnea severity at peak exercise (P < .01). Relative importance analysis showed that the presence of dynamic hyperinflation and perceived muscular leg fatigue were the largest contributors. Pulmonary rehabilitation programs may consider strategies to reduce dynamic hyperinflation and promote muscular function to best improve exercise-related dyspnea in this patient group.

Local nitric oxide synthase inhibition reduces skeletal muscle glucose uptake but not capillary blood flow during in situ muscle contraction in rats.

PubMed

Ross, Renee M; Wadley, Glenn D; Clark, Michael G; Rattigan, Stephen; McConell, Glenn K

2007-12-01

We have previously shown in humans that local infusion of a nitric oxide synthase (NOS) inhibitor into the femoral artery attenuates the increase in leg glucose uptake during exercise without influencing total leg blood flow. However, rodent studies examining the effect of NOS inhibition on contraction-stimulated skeletal muscle glucose uptake have yielded contradictory results. This study examined the effect of local infusion of an NOS inhibitor on skeletal muscle glucose uptake (2-deoxyglucose) and capillary blood flow (contrast-enhanced ultrasound) during in situ contractions in rats. Male hooded Wistar rats were anesthetized and one hindleg electrically stimulated to contract (2 Hz, 0.1 ms) for 30 min while the other leg rested. After 10 min, the NOS inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) (arterial concentration of 5 micromol/l) or saline was infused into the epigastric artery of the contracting leg. Local NOS inhibition had no effect on blood pressure, heart rate, or muscle contraction force. Contractions increased (P < 0.05) skeletal muscle NOS activity, and this was prevented by L-NAME infusion. NOS inhibition caused a modest significant (P < 0.05) attenuation of the increase in femoral blood flow during contractions, but importantly there was no effect on capillary recruitment. NOS inhibition attenuated (P < 0.05) the increase in contraction-stimulated skeletal muscle glucose uptake by approximately 35%, without affecting AMP-activated protein kinase (AMPK) activation. NOS inhibition attenuated increases in skeletal muscle glucose uptake during contraction without influencing capillary recruitment, suggesting that NO is critical for part of the normal increase in skeletal muscle fiber glucose uptake during contraction.

The Physiological Mechanisms of Performance Enhancement with Sprint Interval Training Differ between the Upper and Lower Extremities in Humans.

PubMed

Zinner, Christoph; Morales-Alamo, David; Ørtenblad, Niels; Larsen, Filip J; Schiffer, Tomas A; Willis, Sarah J; Gelabert-Rebato, Miriam; Perez-Valera, Mario; Boushel, Robert; Calbet, Jose A L; Holmberg, Hans-Christer

2016-01-01

To elucidate the mechanisms underlying the differences in adaptation of arm and leg muscles to sprint training, over a period of 11 days 16 untrained men performed six sessions of 4-6 × 30-s all-out sprints (SIT) with the legs and arms, separately, with a 1-h interval of recovery. Limb-specific VO 2 peak, sprint performance (two 30-s Wingate tests with 4-min recovery), muscle efficiency and time-trial performance (TT, 5-min all-out) were assessed and biopsies from the m. vastus lateralis and m. triceps brachii taken before and after training. VO 2 peak and Wmax increased 3-11% after training, with a more pronounced change in the arms ( P < 0.05). Gross efficiency improved for the arms (+8.8%, P < 0.05), but not the legs (-0.6%). Wingate peak and mean power outputs improved similarly for the arms and legs, as did TT performance. After training, VO 2 during the two Wingate tests was increased by 52 and 6% for the arms and legs, respectively ( P < 0.001). In the case of the arms, VO 2 was higher during the first than second Wingate test (64 vs. 44%, P < 0.05). During the TT, relative exercise intensity, HR, VO 2 , VCO 2 , V E , and V t were all lower during arm-cranking than leg-pedaling, and oxidation of fat was minimal, remaining so after training. Despite the higher relative intensity, fat oxidation was 70% greater during leg-pedaling ( P = 0.017). The aerobic energy contribution in the legs was larger than for the arms during the Wingate tests, although VO 2 for the arms was enhanced more by training, reducing the O 2 deficit after SIT. The levels of muscle glycogen, as well as the myosin heavy chain composition were unchanged in both cases, while the activities of 3-hydroxyacyl-CoA-dehydrogenase and citrate synthase were elevated only in the legs and capillarization enhanced in both limbs. Multiple regression analysis demonstrated that the variables that predict TT performance differ for the arms and legs. The primary mechanism of adaptation to SIT by both the arms and legs is enhancement of aerobic energy production. However, with their higher proportion of fast muscle fibers, the arms exhibit greater plasticity.

The Physiological Mechanisms of Performance Enhancement with Sprint Interval Training Differ between the Upper and Lower Extremities in Humans

PubMed Central

Zinner, Christoph; Morales-Alamo, David; Ørtenblad, Niels; Larsen, Filip J.; Schiffer, Tomas A.; Willis, Sarah J.; Gelabert-Rebato, Miriam; Perez-Valera, Mario; Boushel, Robert; Calbet, Jose A. L.; Holmberg, Hans-Christer

2016-01-01

To elucidate the mechanisms underlying the differences in adaptation of arm and leg muscles to sprint training, over a period of 11 days 16 untrained men performed six sessions of 4–6 × 30-s all-out sprints (SIT) with the legs and arms, separately, with a 1-h interval of recovery. Limb-specific VO2peak, sprint performance (two 30-s Wingate tests with 4-min recovery), muscle efficiency and time-trial performance (TT, 5-min all-out) were assessed and biopsies from the m. vastus lateralis and m. triceps brachii taken before and after training. VO2peak and Wmax increased 3–11% after training, with a more pronounced change in the arms (P < 0.05). Gross efficiency improved for the arms (+8.8%, P < 0.05), but not the legs (−0.6%). Wingate peak and mean power outputs improved similarly for the arms and legs, as did TT performance. After training, VO2 during the two Wingate tests was increased by 52 and 6% for the arms and legs, respectively (P < 0.001). In the case of the arms, VO2 was higher during the first than second Wingate test (64 vs. 44%, P < 0.05). During the TT, relative exercise intensity, HR, VO2, VCO2, VE, and Vt were all lower during arm-cranking than leg-pedaling, and oxidation of fat was minimal, remaining so after training. Despite the higher relative intensity, fat oxidation was 70% greater during leg-pedaling (P = 0.017). The aerobic energy contribution in the legs was larger than for the arms during the Wingate tests, although VO2 for the arms was enhanced more by training, reducing the O2 deficit after SIT. The levels of muscle glycogen, as well as the myosin heavy chain composition were unchanged in both cases, while the activities of 3-hydroxyacyl-CoA-dehydrogenase and citrate synthase were elevated only in the legs and capillarization enhanced in both limbs. Multiple regression analysis demonstrated that the variables that predict TT performance differ for the arms and legs. The primary mechanism of adaptation to SIT by both the arms and legs is enhancement of aerobic energy production. However, with their higher proportion of fast muscle fibers, the arms exhibit greater plasticity. PMID:27746738

Improving Exercise Adherence and Physical Measures in English-Speaking Latina Women.

PubMed

Martin, Lorena; Signorile, Joseph F; Kahn, Barbara E; Perkins, Andrew W; Ahn, Soyeon; Perry, Arlette C

2015-12-01

Epidemiological data have established that lack of physical activity increases risk factors for chronic diseases. Data also suggests that physical activity participation is lowest in minority women, particularly Latinas, and that the nature of the exercise and attitudes toward exercise may influence exercise adherence. The purpose of this study was to determine the effect of hypertrophy training (HT) or power training (PT) used concomitantly with evaluative conditioning (EC) or neutral conditioning (NC) on exercise adherence as well as in physical and psychosocial variables in Latina women. EC is a behavioral method using paired stimuli to develop and strengthen new associations in memory. Two hundred thirty-one English-speaking Latina women (mean ± SD, age 36.8 ± 15.9 years) were randomly assigned to standard HT or high-speed circuit PT and then further stratified to receive EC or NC. One hundred forty-two Latina women completed pre- and posttesting. For HT, EC produced significantly greater exercise time across the training period than NC. HT and PT both significantly improved all physical, functional, and psychosocial variables, with exception of leg extension and usual gait speed (p < 0.05). EC can positively impact exercise adherence during HT in Latina women; while body composition, neuromuscular, and functional performances can be increased using HT and PT independent of psychological conditioning.

Nonparetic Knee Extensor Strength Is the Determinant of Exercise Capacity of Community-Dwelling Stroke Survivors

PubMed Central

Wang, Wei-Te; Huang, Ling-Tzu; Chou, Ya-Hui; Wei, Ta-Sen; Lin, Chung-Che

2014-01-01

Objective. To investigate the relationship among walking speed, exercise capacity, and leg strength in community dwelling stroke subjects and to evaluate which one was the leading determinant factor of them. Design. This is a descriptive, cross-sectional study. Thirty-five chronic stroke patients who were able to walk independently in their community were enrolled. Walking speed was evaluated by using the 12-meter walking test. A maximal exercise test was used to determine the stroke subjects' exercise capacity. Knee extensor strength, measured as isokinetic torque, was assessed by isokinetic dynamometer. Results. The main walking speed of our subjects was 0.52 m/s. Peak oxygen uptake (VO2 peak) was 1.21 ± 0.43 L/min. Knee extensor strength, no matter whether paretic or nonparetic side, was significantly correlated to 12-meter walking speed and exercise capacity. Linear regression also showed the strength of the affected knee extensor was the determinant of walking speed and that of the nonparetic knee extensor was the determinant of exercise capacity in community dwelling stroke subjects. Conclusions. Walking speed and peak oxygen uptake were markedly decreased after stroke. Knee extensor strength of nonparetic leg was the most important determinant of exercise capacity of the community-dwelling stroke subjects. Knee extensor strengthening should be emphasized to help stroke patient to achieve optimal community living. PMID:25197712

Nonparetic knee extensor strength is the determinant of exercise capacity of community-dwelling stroke survivors.

PubMed

Wang, Wei-Te; Huang, Ling-Tzu; Chou, Ya-Hui; Wei, Ta-Sen; Lin, Chung-Che

2014-01-01

To investigate the relationship among walking speed, exercise capacity, and leg strength in community dwelling stroke subjects and to evaluate which one was the leading determinant factor of them. This is a descriptive, cross-sectional study. Thirty-five chronic stroke patients who were able to walk independently in their community were enrolled. Walking speed was evaluated by using the 12-meter walking test. A maximal exercise test was used to determine the stroke subjects' exercise capacity. Knee extensor strength, measured as isokinetic torque, was assessed by isokinetic dynamometer. The main walking speed of our subjects was 0.52 m/s. Peak oxygen uptake (VO₂ peak) was 1.21 ± 0.43 L/min. Knee extensor strength, no matter whether paretic or nonparetic side, was significantly correlated to 12-meter walking speed and exercise capacity. Linear regression also showed the strength of the affected knee extensor was the determinant of walking speed and that of the nonparetic knee extensor was the determinant of exercise capacity in community dwelling stroke subjects. Walking speed and peak oxygen uptake were markedly decreased after stroke. Knee extensor strength of nonparetic leg was the most important determinant of exercise capacity of the community-dwelling stroke subjects. Knee extensor strengthening should be emphasized to help stroke patient to achieve optimal community living.

Evaluation of Metabolic Stress between Jumping at Different Cadences on the Digi-Jump Machine

PubMed Central

LYONS, THOMAS S.; NAVALTA, JAMES W.; CALLAHAN, ZACHARY J.

2010-01-01

The American College of Sports Medicine (ACSM) recommends that healthy adults achieve a minimum of thirty minutes of moderate intensity aerobic exercise five days per week. While cycling, walking, and jogging are commonly observed methods of achieving these recommendations, another option may be repetitive jumping. The purpose of this study was to examine the metabolic responses between repetitive jumping at a cadence of 120 jumps per minute (JPMs) vs. 100 JPMs when utilizing the Digi-Jump machine. Twenty-eight subjects completed two jumping trials, one at 120 JPMs and one at 100 JPMs. Subjects jumped until volitional exhaustion, or for a maximum of fifteen minutes. Oxygen uptake (VO2), heart rate (HR), respiratory exchange ratio (RER), and rating of perceived exertion (RPE) were assessed each minute of each exercise trial. RPE was differentiated, in that subjects reported perceived exertion of their total body, their upper-leg, and their lower leg. Results of this study indicated that there was no significant difference between the two trials for VO2, HR, or total body RPE. Differences were reported between trials for peak and average RER, with the 120 JPM trial eliciting a lower RER for both (peak: 1.08 ± .087 vs. 1.17 ± .1 p=.000; average: .99 ± .076 vs. 1.04 ± .098 p=.002), peak upper leg RPE (120: 15.29 ± 3.89 vs. 100: 16.75 ± 2.52 p=.022), and average lower leg RPE (120: 15.04 ± 2.55 vs. 100: 13.94 ± 2.02 p=.019). Also, there was a significant difference in exercise duration between the trials, with subjects able to exercise longer during the 120 JPM trial (12.4 ± 3.42 mins vs. 9.68 ± 4.31 mins p=.000). These data indicate that while the physiological stress may not be different between the two trials as indicated by VO2 and HR, the 120 JPM trial appears less strenuous as evidenced by RER values and by subjects’ ability to exercise longer at that cadence. PMID:27182351

Intramuscular deoxygenation during exercise in patients who have chronic anterior compartment syndrome of the leg

NASA Technical Reports Server (NTRS)

Mohler, L. R.; Styf, J. R.; Pedowitz, R. A.; Hargens, A. R.; Gershuni, D. H.

1997-01-01

Currently, the definitive diagnosis of chronic compartment syndrome is based on invasive measurements of intracompartmental pressure. We measured the intramuscular pressure and the relative oxygenation in the anterior compartment of the leg in eighteen patients who were suspected of having chronic compartment syndrome as well as in ten control subjects before, during, and after exercise. Chronic compartment syndrome was considered to be present if the intramuscular pressure was at least fifteen millimeters of mercury (2.00 kilopascals) before exercise, at least thirty millimeters of mercury (4.00 kilopascals) one minute after exercise, or at least twenty millimeters of mercury (2.67 kilopascals) five minutes after exercise. Changes in relative oxygenation were measured with use of the non-invasive method of near-infrared spectroscopy. In all patients and subjects, there was rapid relative deoxygenation after the initiation of exercise, the level of oxygenation remained relatively stable during continued exercise, and there was reoxygenation to a level that exceeded the pre-exercise resting level after the cessation of exercise. During exercise, maximum relative deoxygenation in the patients who had chronic compartment syndrome (mean relative deoxygenation [and standard error], -290 +/- 39 millivolts) was significantly greater than that in the patients who did not have chronic compartment syndrome (-190 +/- 10 millivolts) and that in the control subjects (-179 +/- 14 millivolts) (p < 0.05 for both comparisons). In addition, the interval between the cessation of exercise and the recovery of the pre-exercise resting level of oxygenation was significantly longer for the patients who had chronic compartment syndrome (184 +/- 54 seconds) than for the patients who did not have chronic compartment syndrome (39 +/- 19 seconds) and the control subjects (33 +/- 10 seconds) (p < 0.05 for both comparisons).

Tai Chi and balance control.

PubMed

Wong, Alice M K; Lan, Ching

2008-01-01

Balance function begins to decline from middle age on, and poor balance function increases the risk of fall and injury. Suitable exercise training may improve balance function and prevent accidental falls. The coordination of visual, proprioceptive, vestibular and musculoskeletal system is important to maintain balance. Balance function can be evaluated by functional balance testing and sensory organization testing. Tai Chi Chuan (TC) is a popular conditioning exercise in the Chinese community, and recent studies substantiate that TC is effective in balance function enhancement and falls prevention. In studies utilizing functional balance testing, TC may increase the duration of one-leg standing and the distance of functional reach. In studies utilizing sensory organization testing, TC improves static and dynamic balance, especially in more challenging sensory perturbed condition. Therefore, TC may be prescribed as an alternative exercise program for elderly subjects or balance-impaired patients. Participants can choose to perform a complete set of TC or selected movements according to their needs. In conclusion, TC may improve balance function and is appropriate for implementation in the community.

Effect of Capacitive and Resistive electric transfer on changes in muscle flexibility and lumbopelvic alignment after fatiguing exercise.

PubMed

Yokota, Yuki; Sonoda, Takuya; Tashiro, Yuto; Suzuki, Yusuke; Kajiwara, Yu; Zeidan, Hala; Nakayama, Yasuaki; Kawagoe, Mirei; Shimoura, Kanako; Tatsumi, Masataka; Nakai, Kengo; Nishida, Yuichi; Bito, Tsubasa; Yoshimi, Soyoka; Aoyama, Tomoki

2018-05-01

[Purpose] This study aimed to clarify the effects of Capacitive and Resistive electric transfer (CRet) on changes in muscle flexibility and lumbopelvic alignment after fatiguing exercise. [Subjects and Methods] Twenty-two healthy males were assigned into either the CRet (n=11) or control (n=11) group. Fatiguing exercise and CRet intervention were applied at the quadriceps muscle of the participants' dominant legs. The Ely test, pelvic tilt, lumbar lordosis, and superficial temperature were measured before and after exercise and for 30 minutes after intervention. Statistical analysis was performed using one-way analysis of variance, with Tukey's post-hoc multiple comparison test to clarify within-group changes and Student's t-test to clarify between-group differences. [Results] The Ely test and pelvic tilt were significantly different in both groups after exercise, but there was no difference in the CRet group after intervention. Superficial temperature significantly increased in the CRet group for 30 minutes after intervention, in contrast to after the exercise and intervention in the control group. There was no significant between-group difference at any timepoint, except in superficial temperature. [Conclusion] CRet could effectively improve muscle flexibility and lumbopelvic alignment after fatiguing exercise.

Colostrum supplementation protects against exercise - induced oxidative stress in skeletal muscle in mice

PubMed Central

2012-01-01

Background This study examined the effects of bovine colostrum on exercise –induced modulation of antioxidant parameters in skeletal muscle in mice. Adult male BALB/c mice were randomly divided into four groups (control, colostrum alone, exercise and exercise with colostrum) and each group had three subgroups (day 0, 21 and 42). Colostrum groups of mice were given a daily oral supplement of 50 mg/kg body weight of bovine colostrum and the exercise group of mice were made to exercise on the treadmill for 30 minutes per day. Total antioxidants, lipid hydroperoxides, xanthine oxidase and super oxide dismutase level was assayed from the homogenate of hind limb skeletal muscle. Results Exercise—induced a significant oxidative stress in skeletal muscles as evidenced by the elevated lipid hydroperoxides and xanthine oxidase levels. There was a significant decrease in skeletal muscle total antioxidants and superoxide dismutase levels. Daily colostrum supplement significantly reduced the lipid hydroperoxides and xanthine oxidase enzyme level and increased the total antioxidant levels in the leg muscle. Conclusion Thus, the findings of this study showed that daily bovine colostrum supplementation was beneficial to skeletal muscle to reduce the oxidant-induced damage during muscular exercise. PMID:23173926

Effect of Capacitive and Resistive electric transfer on changes in muscle flexibility and lumbopelvic alignment after fatiguing exercise

PubMed Central

Yokota, Yuki; Sonoda, Takuya; Tashiro, Yuto; Suzuki, Yusuke; Kajiwara, Yu; Zeidan, Hala; Nakayama, Yasuaki; Kawagoe, Mirei; Shimoura, Kanako; Tatsumi, Masataka; Nakai, Kengo; Nishida, Yuichi; Bito, Tsubasa; Yoshimi, Soyoka; Aoyama, Tomoki

2018-01-01

[Purpose] This study aimed to clarify the effects of Capacitive and Resistive electric transfer (CRet) on changes in muscle flexibility and lumbopelvic alignment after fatiguing exercise. [Subjects and Methods] Twenty-two healthy males were assigned into either the CRet (n=11) or control (n=11) group. Fatiguing exercise and CRet intervention were applied at the quadriceps muscle of the participants’ dominant legs. The Ely test, pelvic tilt, lumbar lordosis, and superficial temperature were measured before and after exercise and for 30 minutes after intervention. Statistical analysis was performed using one-way analysis of variance, with Tukey’s post-hoc multiple comparison test to clarify within-group changes and Student’s t-test to clarify between-group differences. [Results] The Ely test and pelvic tilt were significantly different in both groups after exercise, but there was no difference in the CRet group after intervention. Superficial temperature significantly increased in the CRet group for 30 minutes after intervention, in contrast to after the exercise and intervention in the control group. There was no significant between-group difference at any timepoint, except in superficial temperature. [Conclusion] CRet could effectively improve muscle flexibility and lumbopelvic alignment after fatiguing exercise. PMID:29765189

Restoration of plasma volume after 16 days of head-down tilt induced by a single bout of maximal exercise

NASA Technical Reports Server (NTRS)

Convertino, V. A.; Engelke, K. A.; Ludwig, D. A.; Doerr, D. F.

1996-01-01

Seven healthy men performed maximal exercise 24 h before the end of 16 days exposure to 6 degrees head-down tilt (HDT) to test the hypothesis that such an exercise technique could restore plasma volume (PV) at the end of a simulated space mission. Exercise consisted of supine cycling with graded work rates increasing by 16 W/min to volitional fatigue and required an average of 16 min. The experimental protocol was a standard cross-over design in which the order of treatment (exercise or control) was counterbalanced across all seven subjects. PV, fluid intake (ad libitum), urine output, renal function, and hormones associated with fluid homeostasis were measured before HDT, 24 h before the end of HDT just prior to exercise, and at the end of HDT 24 h after exercise. HDT reduced PV by 16% in both control and exercise conditions. Maximal exercise completely restored plasma volume within 24 h to 3.9 +/- 3.2% of pre-HDT levels despite continued HDT. Compared with control, exercise induced a 660-ml larger positive fluid balance because of greater fluid intake and reduced urine volume during the 24 h after exercise. These results suggest that one bout of maximal leg exercise before return from 16 days of spaceflight may be completely effective in stimulating thirst and restoring plasma volume to preflight levels.

Effects of Resistance Training on Fatigue-Related Domains of Quality of Life and Mood During Pregnancy: A Randomized Trial in Pregnant Women With Increased Risk of Back Pain.

PubMed

OʼConnor, Patrick J; Poudevigne, Mélanie S; Johnson, Kristen E; Brito de Araujo, Juliana; Ward-Ritacco, Christie L

2018-04-01

The aim of the study was to test whether the adoption of twice weekly, low-to-moderate intensity resistance training during weeks 22 to 34 of pregnancy can improve quality of life and mood. A parallel-group trial was conducted. Women in their second trimester (N = 134) were randomly assigned to 12 weeks of wait list, bimonthly pregnancy education classes, or twice weekly low-to-moderate intensity resistance training. Resistance training involved one abdominal exercise with no external load and five exercises (leg extension, leg press, arm lat pull, leg curl, and lumbar extension) with an external load that gradually progressed, and the total active exercise time during each exercise session was approximately 17 minutes. Quality of life and mood were measured before and after the interventions using the 36-item Short Form Health Survey and Profile of Mood States. Intent-to-treat mixed-model analyses of variance (3 groups by 2 times, pre- and postintervention) tested the hypothesis that outcomes would worsen for the controls and not change or improve for the resistance training group. The group by time interaction (F(2,131) = 3.144, η = .046, p = .046) for 36-item Short Form Health Survey vitality and subsequent simple main effects showed that scores were unchanged across time after resistance training (-1.8 (14.8)) but significantly decreased for the education (-6.44 (12.69), t = 3.408, df = 44, p = .001) and wait list (-9.11 (14.78), t = 4.135, df = 44, p < .001) groups, whereas posttest vitality scores for the pregnancy group (45.9 (16.9)) were significantly higher than the wait list (40.1 (16.3), t = 1.989, df = 87, p = .05) but not the education group (42.1 (15.4), p = .27). Profile of mood states fatigue scores showed a similar pattern. Adverse changes in symptoms of energy and fatigue during pregnancy are attenuated by adopting low-to-moderate intensity resistance training. Clinicaltrials.gov, NCT02557893.

High and odd impact exercise training improved physical function and fall risk factors in community-dwelling older men

PubMed Central

Allison, Sarah J.; Brooke-Wavell, Katherine; Folland, Jonathan

2018-01-01

High impact exercise programmes can improve bone strength, but little is known about whether this type of training further benefits fracture risk by improving physical function in older people. Objectives: This study investigated the influence of high impact exercise on balance, muscle function and morphology in older men. Methods: Fifty, healthy men (65-80 years) were assigned to a 6-month multidirectional hopping programme (TG) and twenty age and physical activity matched volunteers served as controls (CG). Before and after training, muscle function (hop performance, leg press and plantar- and dorsiflexion strength) and physiological determinants (muscle thickness and architecture) as well as balance control (sway path, one leg stance duration) were measured. Resting gastrocnemius medialis (GM) muscle thickness and architecture were assessed using ultrasonography. Results: Significant improvements in hop impulse (+12%), isometric leg-press strength (+4%) and ankle plantarflexion strength (+11%), dorsiflexor strength (+20%) were found in the TG compared to the CG (ANOVA interaction, P<0.05) and unilateral stance time improved over time for TG. GM muscle thickness indicated modest hypertrophy (+4%), but muscle architecture was unchanged. Conclusion: The positive changes in strength and balance after high impact and odd impact training would be expected to improve physical function in older adults. PMID:29504585

High and odd impact exercise training improved physical function and fall risk factors in community-dwelling older men.

PubMed

Allison, Sarah J; Brooke-Wavell, Katherine; Folland, Jonathan

2018-03-01

High impact exercise programmes can improve bone strength, but little is known about whether this type of training further benefits fracture risk by improving physical function in older people. This study investigated the influence of high impact exercise on balance, muscle function and morphology in older men. Fifty, healthy men (65-80 years) were assigned to a 6-month multidirectional hopping programme (TG) and twenty age and physical activity matched volunteers served as controls (CG). Before and after training, muscle function (hop performance, leg press and plantar- and dorsiflexion strength) and physiological determinants (muscle thickness and architecture) as well as balance control (sway path, one leg stance duration) were measured. Resting gastrocnemius medialis (GM) muscle thickness and architecture were assessed using ultrasonography. Significant improvements in hop impulse (+12%), isometric leg-press strength (+4%) and ankle plantarflexion strength (+11%), dorsiflexor strength (+20%) were found in the TG compared to the CG (ANOVA interaction, P⟨0.05) and unilateral stance time improved over time for TG. GM muscle thickness indicated modest hypertrophy (+4%), but muscle architecture was unchanged. The positive changes in strength and balance after high impact and odd impact training would be expected to improve physical function in older adults.

Small and inconsistent effects of whole body vibration on athletic performance: a systematic review and meta-analysis.

PubMed

Hortobágyi, Tibor; Lesinski, Melanie; Fernandez-Del-Olmo, Miguel; Granacher, Urs

2015-08-01

We quantified the acute and chronic effects of whole body vibration on athletic performance or its proxy measures in competitive and/or elite athletes. Systematic literature review and meta-analysis. Whole body vibration combined with exercise had an overall 0.3 % acute effect on maximal voluntary leg force (-6.4 %, effect size = -0.43, 1 study), leg power (4.7 %, weighted mean effect size = 0.30, 6 studies), flexibility (4.6 %, effect size = -0.12 to 0.22, 2 studies), and athletic performance (-1.9 %, weighted mean effect size = 0.26, 6 studies) in 191 (103 male, 88 female) athletes representing eight sports (overall effect size = 0.28). Whole body vibration combined with exercise had an overall 10.2 % chronic effect on maximal voluntary leg force (14.6 %, weighted mean effect size = 0.44, 5 studies), leg power (10.7 %, weighted mean effect size = 0.42, 9 studies), flexibility (16.5 %, effect size = 0.57 to 0.61, 2 studies), and athletic performance (-1.2 %, weighted mean effect size = 0.45, 5 studies) in 437 (169 male, 268 female) athletes (overall effect size = 0.44). Whole body vibration has small and inconsistent acute and chronic effects on athletic performance in competitive and/or elite athletes. These findings lead to the hypothesis that neuromuscular adaptive processes following whole body vibration are not specific enough to enhance athletic performance. Thus, other types of exercise programs (e.g., resistance training) are recommended if the goal is to improve athletic performance.

Roles of sedentary aging and lifelong physical activity in exchange of glutathione across exercising human skeletal muscle.

PubMed

Nyberg, Michael; Mortensen, Stefan P; Cabo, Helena; Gomez-Cabrera, Mari-Carmen; Viña, Jose; Hellsten, Ylva

2014-08-01

Reactive oxygen species (ROS) are important signaling molecules with regulatory functions, and in young and adult organisms, the formation of ROS is increased during skeletal muscle contractions. However, ROS can be deleterious to cells when not sufficiently counterbalanced by the antioxidant system. Aging is associated with accumulation of oxidative damage to lipids, DNA, and proteins. Given the pro-oxidant effect of skeletal muscle contractions, this effect of age could be a result of excessive ROS formation. We evaluated the effect of acute exercise on changes in blood redox state across the leg of young (23 ± 1 years) and older (66 ± 2 years) sedentary humans by measuring the whole blood concentration of the reduced (GSH) and oxidized (GSSG) forms of the antioxidant glutathione. To assess the role of physical activity, lifelong physically active older subjects (62 ± 2 years) were included. Exercise increased the venous concentration of GSSG in an intensity-dependent manner in young sedentary subjects, suggesting an exercise-induced increase in ROS formation. In contrast, venous GSSG levels remained unaltered during exercise in the older sedentary and active groups despite a higher skeletal muscle expression of the superoxide-generating enzyme NADPH oxidase. Arterial concentration of GSH and expression of antioxidant enzymes in skeletal muscle of older active subjects were increased. The potential impairment in exercise-induced ROS formation may be an important mechanism underlying skeletal muscle and vascular dysfunction with sedentary aging. Lifelong physical activity upregulates antioxidant systems, which may be one of the mechanisms underlying the lack of exercise-induced increase in GSSG. Copyright © 2014 Elsevier Inc. All rights reserved.

The Effect of an Acute After-School Exercise Bout on Percentage of Body Fat Using Leg-to-Leg Bioelectrical Impedance Analysis in Children

ERIC Educational Resources Information Center

Andreacci, Joseph L.; Dixon, Curt B.; Rompolski, Krista; VanGorden, Kelly M.

2008-01-01

Bioelectrical impedance analysis (BIA) is a fast, easy to administer, and relatively inexpensive method of evaluating body composition. Due to the ease of operation, interest in using BIA to estimate percentage of body fat (%BF) has grown, especially in settings where body composition assessments are often performed without the benefit of…

Importance of eccentric actions in performance adaptations to resistance training

NASA Technical Reports Server (NTRS)

Dudley, Gary A.; Miller, Bruce J.; Buchanan, Paul; Tesch, Per A.

1991-01-01

The importance of eccentric (ecc) muscle actions in resistance training for the maintenance of muscle strength and mass in hypogravity was investigated in experiments in which human subjects, divided into three groups, were asked to perform four-five sets of 6 to 12 repetitions (rep) per set of three leg press and leg extension exercises, 2 days each weeks for 19 weeks. One group, labeled 'con', performed each rep with only concentric (con) actions, while group con/ecc with performed each rep with only ecc actions; the third group, con/con, performed twice as many sets with only con actions. Control subjects did not train. It was found that resistance training wih both con and ecc actions induced greater increases in muscle strength than did training with only con actions.

Cell-free plasma DNA as a novel marker of aseptic inflammation severity related to exercise overtraining.

PubMed

Fatouros, Ioannis G; Destouni, Aspasia; Margonis, Konstantinos; Jamurtas, Athanasios Z; Vrettou, Christina; Kouretas, Dimitrios; Mastorakos, George; Mitrakou, Asimina; Taxildaris, Kiriakos; Kanavakis, Emmanouel; Papassotiriou, Ioannis

2006-09-01

Circulating free plasma DNA is implicated in conditions associated with tissue injury, including exercise-induced inflammation, and thus is a potential marker for athletic overtraining. We measured free plasma DNA along with C-reactive protein (CRP), creatine kinase (CK), and uric acid (UA) in 17 recreationally trained men participating in a 12-week resistance training regimen (8 resistance multi-joint exercises selected to stress the entire musculature: bench press, squat, leg press, snatch, hang clean, dead lifts, barbell arm curls, and rowing), consisting of 4 training periods (t1, t2, t3, and t4). Plasma DNA concentrations increased markedly after t1, t2, and t3 and returned to baseline after t4. There were substantial differences between t2 and t1 and between t3 and t2 plasma DNA concentrations. CRP increased by 300% after t2 and by 400% after t3 (there was no difference between t2 and t3 CRP values) compared with baseline (t0). CK increased only after t3. UA increased after t2 and t3, with a greater increase after t3. This study demonstrates that, after chronic excessive resistance exercise, plasma DNA concentrations increase in proportion to training load, suggesting that plasma DNA may be a sensitive marker for overtraining-induced inflammation.

Perfusion dynamics assessment with Power Doppler ultrasound in skeletal muscle during maximal and submaximal cycling exercise.

PubMed

Heres, H M; Schoots, T; Tchang, B C Y; Rutten, M C M; Kemps, H M C; van de Vosse, F N; Lopata, R G P

2018-06-01

Assessment of limitations in the perfusion dynamics of skeletal muscle may provide insight in the pathophysiology of exercise intolerance in, e.g., heart failure patients. Power doppler ultrasound (PDUS) has been recognized as a sensitive tool for the detection of muscle blood flow. In this volunteer study (N = 30), a method is demonstrated for perfusion measurements in the vastus lateralis muscle, with PDUS, during standardized cycling exercise protocols, and the test-retest reliability has been investigated. Fixation of the ultrasound probe on the upper leg allowed for continuous PDUS measurements. Cycling exercise protocols included a submaximal and an incremental exercise to maximal power. The relative perfused area (RPA) was determined as a measure of perfusion. Absolute and relative reliability of RPA amplitude and kinetic parameters during exercise (onset, slope, maximum value) and recovery (overshoot, decay time constants) were investigated. A RPA increase during exercise followed by a signal recovery was measured in all volunteers. Amplitudes and kinetic parameters during exercise and recovery showed poor to good relative reliability (ICC ranging from 0.2-0.8), and poor to moderate absolute reliability (coefficient of variation (CV) range 18-60%). A method has been demonstrated which allows for continuous (Power Doppler) ultrasonography and assessment of perfusion dynamics in skeletal muscle during exercise. The reliability of the RPA amplitudes and kinetics ranges from poor to good, while the reliability of the RPA increase in submaximal cycling (ICC = 0.8, CV = 18%) is promising for non-invasive clinical assessment of the muscle perfusion response to daily exercise.

Improved Exercise Tolerance with Caffeine Is Associated with Modulation of both Peripheral and Central Neural Processes in Human Participants.

PubMed

Bowtell, Joanna L; Mohr, Magni; Fulford, Jonathan; Jackman, Sarah R; Ermidis, Georgios; Krustrup, Peter; Mileva, Katya N

2018-01-01

Caffeine has been shown to enhance exercise performance and capacity. The mechanisms remain unclear but are suggested to relate to adenosine receptor antagonism, resulting in increased central motor drive, reduced perception of effort, and altered peripheral processes such as enhanced calcium handling and extracellular potassium regulation. Our aims were to investigate how caffeine (i) affects knee extensor PCr kinetics and pH during repeated sets of single-leg knee extensor exercise to task failure and (ii) modulates the interplay between central and peripheral neural processes. We hypothesized that the caffeine-induced extension of exercise capacity during repeated sets of exercise would occur despite greater disturbance of the muscle milieu due to enhanced peripheral and corticospinal excitatory output, central motor drive, and muscle contractility. Nine healthy active young men performed five sets of intense single-leg knee extensor exercise to task failure on four separate occasions: for two visits (6 mg·kg -1 caffeine vs placebo), quadriceps 31 P-magnetic resonance spectroscopy scans were performed to quantify phosphocreatine kinetics and pH, and for the remaining two visits (6 mg·kg -1 caffeine vs placebo), femoral nerve electrical and transcranial magnetic stimulation of the quadriceps cortical motor area were applied pre- and post exercise. The total exercise time was 17.9 ± 6.0% longer in the caffeine (1,225 ± 86 s) than in the placebo trial (1,049 ± 73 s, p  = 0.016), and muscle phosphocreatine concentration and pH ( p < 0.05) were significantly lower in the latter sets of exercise after caffeine ingestion. Voluntary activation (VA) (peripheral, p  = 0.007; but not supraspinal, p  = 0.074), motor-evoked potential (MEP) amplitude ( p  = 0.007), and contractility (contraction time, p  = 0.009; and relaxation rate, p  = 0.003) were significantly higher after caffeine consumption, but at task failure MEP amplitude and VA were not different from placebo. Caffeine prevented the reduction in M-wave amplitude that occurred at task failure ( p  = 0.039). Caffeine supplementation improved high-intensity exercise tolerance despite greater-end exercise knee extensor phosphocreatine depletion and H + accumulation. Caffeine-induced increases in central motor drive and corticospinal excitability were attenuated at task failure. This may have been induced by the afferent feedback of the greater disturbance of the muscle milieu, resulting in a stronger inhibitory input to the spinal and supraspinal motor neurons. However, causality needs to be established through further experiments.

Acute exercise and physiological insulin induce distinct phosphorylation signatures on TBC1D1 and TBC1D4 proteins in human skeletal muscle.

PubMed

Treebak, Jonas T; Pehmøller, Christian; Kristensen, Jonas M; Kjøbsted, Rasmus; Birk, Jesper B; Schjerling, Peter; Richter, Erik A; Goodyear, Laurie J; Wojtaszewski, Jørgen F P

2014-01-15

We investigated the phosphorylation signatures of two Rab-GTPase activating proteins TBC1D1 and TBC1D4 in human skeletal muscle in response to physical exercise and physiological insulin levels induced by a carbohydrate rich meal using a paired experimental design. Eight healthy male volunteers exercised in the fasted or fed state and muscle biopsies were taken before and immediately after exercise. We identified TBC1D1/4 phospho-sites that (1) did not respond to exercise or postprandial increase in insulin (TBC1D4: S666), (2) responded to insulin only (TBC1D4: S318), (3) responded to exercise only (TBC1D1: S237, S660, S700; TBC1D4: S588, S751), and (4) responded to both insulin and exercise (TBC1D1: T596; TBC1D4: S341, T642, S704). In the insulin-stimulated leg, Akt phosphorylation of both T308 and S473 correlated significantly with multiple sites on both TBC1D1 (T596) and TBC1D4 (S318, S341, S704). Interestingly, in the exercised leg in the fasted state TBC1D1 phosphorylation (S237, T596) correlated significantly with the activity of the α2/β2/γ3 AMPK trimer, whereas TBC1D4 phosphorylation (S341, S704) correlated with the activity of the α2/β2/γ1 AMPK trimer. Our data show differential phosphorylation of TBC1D1 and TBC1D4 in response to physiological stimuli in human skeletal muscle and support the idea that Akt and AMPK are upstream kinases. TBC1D1 phosphorylation signatures were comparable between in vitro contracted mouse skeletal muscle and exercised human muscle, and we show that AMPK regulated phosphorylation of these sites in mouse muscle. Contraction and exercise elicited a different phosphorylation pattern of TBC1D4 in mouse compared with human muscle, and although different circumstances in our experimental setup may contribute to this difference, the observation exemplifies that transferring findings between species is problematic.

Comparison of Gait During Treadmill Exercise While Supine in Lower Body Negative Pressure (LBNP), Supine with Bungee Resistance and Upright in Normal Gravity

NASA Technical Reports Server (NTRS)

Boda, Wanda; Hargens, Alan R.; Aratow, Michael; Ballard, Richard E.; Hutchinson, Karen; Murthy, Gita; Campbell, James

1994-01-01

The purpose of this study is to compare footward forces, gait kinematics, and muscle activation patterns (EMG) generated during supine treadmill exercise against LBNP with the same parameters during supine bungee resistance exercise and upright treadmill exercise. We hypothesize that the three conditions will be similar. These results will help validate treadmill exercise during LBNP as a viable technique to simulate gravity during space flight. We are evaluating LBNP as a means to load the musculoskeletal and cardiovascular systems without gravity. Such loading should help prevent physiologic deconditioning during space flight. The best ground-based simulation of LBNP treadmill exercise in microgravity is supine LBNP treadmill exercise on Earth because the supine footward force vector is neither directed nor supplemented by Earth's gravity. Previous results from HR-95 ("Dynamics of footward force and leg intramuscular pressure during exercise against supine LBNP and upright standing in normal gravity") indicate that supine plantar-/dorsiflexion exercise in LBNP at 100 mm Hg produces similar ground reaction forces, musculoskeletal stress, and VO2 to those during upright exercise against Earth's gravity. However, elevations of leg volume and heart rate indicate that cardiovascular stress during 100 mm Hg LBNP exercise exceeds that during 1 g exercise. Therefore, the need arose to reduce the cardiovascular stress of LBNP, while maintaining LBNP-induced reaction forces. To this end, we determined that mild plantar-/dorsiflexion exercise during LBNP significantly improves tolerance to LBNP via musculovenous pumping and sympathoexcitation; more intense exercise such as walking and running may further improve LBNP tolerance. In addition, two methodological advances have permited us to simulate upright 1 g exercise better with supine LBNP exercise. First, a newly-designed waist seal allows decreased levels of LBNP (50-60 mm Hg) to produce a footward force equaling one body weight

Comparison between linear and daily undulating periodized resistance training to increase strength.

PubMed

Prestes, Jonato; Frollini, Anelena B; de Lima, Cristiane; Donatto, Felipe F; Foschini, Denis; de Cássia Marqueti, Rita; Figueira, Aylton; Fleck, Steven J

2009-12-01

To determine the most effective periodization model for strength and hypertrophy is an important step for strength and conditioning professionals. The aim of this study was to compare the effects of linear (LP) and daily undulating periodized (DUP) resistance training on body composition and maximal strength levels. Forty men aged 21.5 +/- 8.3 and with a minimum 1-year strength training experience were assigned to an LP (n = 20) or DUP group (n = 20). Subjects were tested for maximal strength in bench press, leg press 45 degrees, and arm curl (1 repetition maximum [RM]) at baseline (T1), after 8 weeks (T2), and after 12 weeks of training (T3). Increases of 18.2 and 25.08% in bench press 1 RM were observed for LP and DUP groups in T3 compared with T1, respectively (p < or = 0.05). In leg press 45 degrees , LP group exhibited an increase of 24.71% and DUP of 40.61% at T3 compared with T1. Additionally, DUP showed an increase of 12.23% at T2 compared with T1 and 25.48% at T3 compared with T2. For the arm curl exercise, LP group increased 14.15% and DUP 23.53% at T3 when compared with T1. An increase of 20% was also found at T2 when compared with T1, for DUP. Although the DUP group increased strength the most in all exercises, no statistical differences were found between groups. In conclusion, undulating periodized strength training induced higher increases in maximal strength than the linear model in strength-trained men. For maximizing strength increases, daily intensity and volume variations were more effective than weekly variations.

Exercise interventions and prevention of fall-related fractures in older people: a meta-analysis of randomized controlled trials.

PubMed

Zhao, Renqing; Feng, Feifei; Wang, Xinzheng

2017-02-01

This meta-analysis aimed to determine whether exercise interventions were effective in preventing fall-related fractures in older people. The treatment effects on rate of falls, leg strength and balance were also examined. An electronic database search was conducted in PubMed, EMBASE, the Cochrane library and PEDro up to 1 September 2015. Randomized controlled trials (RCTs) that conducted exercise interventions and reported fall-related fracture data in older people were included. The primary outcome was the treatment effects on fall-related fractures determined by relative risk (RR) and 95% confidence interval (CI). The treatment effects on falls, leg strength and balance were also reported using rate ratio (RaR) with 95% CI and standardized mean difference (SMD) with 95% CI, respectively. Random effects models were used for meta-analysis. Fifteen studies including 3136 participants met the inclusion criteria. Exercise had a beneficial effect on reduction of fall-related fractures, with pooled estimates of RR 0.604 (95% CI 0.453 - 0.840, P  = 0.003, I 2  = 0%). The rate of falls (RaR 0.856, 95% CI 0.778 - 0.941, P  = 0.001, I 2  = 45%) and leg strength (SMD 0.613, 95% CI 0.119 - 1.107, P  = 0.015, I 2  = 76.7%) were also potentially affected by exercise interventions. These only had a marginally beneficial effect on balance (SMD 0.468, 95% CI -0.011 - 0.947, P  = 0.055, I 2  = 93.6%). Our findings implied that exercise interventions were effective in preventing fall-related fractures and reducing risk factors of fall-related fractures in older people. © The Author 2016; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association

No Exacerbation of Knee Joint Pain and Effusion Following Preoperative Progressive Resistance Training in Patients Scheduled for Total Knee Arthroplasty: Secondary Analyses From a Randomized Controlled Trial.

PubMed

Skoffer, Birgit; Dalgas, Ulrik; Maribo, Thomas; Søballe, Kjeld; Mechlenburg, Inger

2017-11-09

Preoperative progressive resistance training (PRT) is controversial in patients scheduled for total knee arthroplasty (TKA), because of the concern that it may exacerbate knee joint pain and effusion. To examine whether preoperative PRT initiated 5 weeks prior to TKA would exacerbate pain and knee effusion, and would allow a progressively increased training load throughout the training period that would subsequently increase muscle strength. Secondary analyses from a randomized controlled trial. University Hospital and a Regional Hospital. A total of 30 patients who were scheduled for TKA due to osteoarthritis and assigned as the intervention group. Patients underwent unilateral PRT (3 sessions per week). Exercise loading was 12 repetitions maximum (RM) with progression toward 8 RM. The training program consisted of 6 exercises performed unilaterally. Before and after each training session, knee joint pain was rated on an 11-point scale, effusion was assessed by measuring the knee joint circumference, and training load was recorded. The first and last training sessions were initiated by 1 RM testing of unilateral leg press, unilateral knee extension, and unilateral knee flexion. The median pain change score from before to after each training session was 0 at all training sessions. The average increase in knee joint effusion across the 12 training sessions was a mean 0.16 cm ± 0.23 cm. No consistent increase in knee joint effusion after training sessions during the training period was found (P = .21). Training load generally increased, and maximal muscle strength improved as follows: unilateral leg press: 18% ± 30% (P = .03); unilateral knee extension: 81% ± 156% (P < .001); and unilateral knee flexion: 53% ± 57% (P < .001). PRT of the affected leg initiated shortly before TKA does not exacerbate knee joint pain and effusion, despite a substantial progression in loading and increased muscle strength. Concerns for side effects such as pain and effusion after PRT seem unfounded. To be determined. Copyright © 2017. Published by Elsevier Inc.

Human skeletal muscle type 1 fibre distribution and response of stress-sensing proteins along the titin molecule after submaximal exhaustive exercise.

PubMed

Koskinen, Satu O A; Kyröläinen, Heikki; Flink, Riina; Selänne, Harri P; Gagnon, Sheila S; Ahtiainen, Juha P; Nindl, Bradley C; Lehti, Maarit

2017-11-01

Early responses of stress-sensing proteins, muscle LIM protein (MLP), ankyrin repeat proteins (Ankrd1/CARP and Ankrd2/Arpp) and muscle-specific RING finger proteins (MuRF1 and MuRF2), along the titin molecule were investigated in the present experiment after submaximal exhaustive exercise. Ten healthy men performed continuous drop jumping unilaterally on a sledge apparatus with a submaximal height until complete exhaustion. Five stress-sensing proteins were analysed by mRNA measurements from biopsies obtained immediately and 3 h after the exercise from exercised vastus lateralis muscle while control biopsies were obtained from non-exercised legs before the exercise. Decreased maximal jump height and increased serum creatine kinase activities as indirect markers for muscle damage and HSP27 immunostainings on muscle biopsies as a direct marker for muscle damage indicated that the current exercised protocol caused muscle damage. mRNA levels for four (MLP, Ankrd1/CARP, MuRF1 and MuRF2) out of the five studied stress sensors significantly (p < 0.05) increased 3 h after fatiguing exercise. The magnitude of MLP and Ankrd2 responses was related to the proportion of type 1 myofibres. Our data showed that the submaximal exhaustive exercise with subject's own physical fitness level activates titin-based stretch-sensing proteins. These results suggest that both degenerative and regenerative pathways are activated in very early phase after the exercise or probably already during the exercise. Activation of these proteins represents an initial step forward adaptive remodelling of the exercised muscle and may also be involved in the initiation of myofibre repair.

Open versus closed kinetic chain exercises for patellar chondromalacia.

PubMed

Bakhtiary, A H; Fatemi, E

2008-02-01

Conservative treatment of patellar chondromalacia has been the subject of several studies. One recommended treatment is a strengthening exercise of the quadriceps muscle, which may be performed in closed or open kinetic chains. This study was designed to compare the effect of straight leg raise (SLR) and semi-squat exercises on the treatment of patellar chondromalacia, which has not been done to date. 32 female university students with a diagnosis of patellar chondromalacia were randomly assigned to two experimental groups: SLR and semi-squat exercise. Before starting exercise protocols, Q angle, maximal isometric voluntary contraction force (MIVCF) of quadriceps, crepitation, circumference of thigh 5 and 10 cm above the patella and patellofemoral pain according to the visual analogue scale (VAS) were assessed. Both groups then followed a 3-week programme of quadriceps muscle strengthening exercises (SLR or semi-squat) starting with 20 exercises twice a day and increasing each session by 5 exercises every 2 days. All measurements were repeated at the end of each week and then again 2 weeks after the 3-week exercise programme. Reduced Q angle (mean differences (SD) 0.8 (0.3), p = 0.016) and crepitation (19.9 (8.5), p = 0.04), and an increase in the MIVCF of the quadriceps (15.8 (5.6), p = 0.01) and thigh circumference (1.5 (0.3), p = 0.001) were found in semi-squat group compared with SLR group. However, patellofemoral pain was decreased significantly in both groups. The results of this study indicate that semi-squat exercises (closed kinetic chain) are more effective than SLR exercise (open kinetic chain) in the treatment of patellar chondromalacia. More studies are needed to investigate the long-term effect of these types of exercise.

The effect of caffeine as an ergogenic aid in anaerobic exercise.

PubMed

Woolf, Kathleen; Bidwell, Wendy K; Carlson, Amanda G

2008-08-01

The study examined caffeine (5 mg/kg body weight) vs. placebo during anaerobic exercise. Eighteen male athletes (24.1+/-5.8 yr; BMI 26.4+/-2.2 kg/m2) completed a leg press, chest press, and Wingate test. During the caffeine trial, more total weight was lifted with the chest press, and a greater peak power was obtained during the Wingate test. No differences were observed between treatments for the leg press and average power, minimum power, and power drop (Wingate test). There was a significant treatment main effect found for postexercise glucose and insulin concentrations; higher concentrations were found in the caffeine trial. A significant interaction effect (treatment and time) was found for cortisol and glucose concentrations; both increased with caffeine and decreased with placebo. Postexercise systolic blood pressure was significantly higher during the caffeine trial. No differences were found between treatments for serum free-fatty-acid concentrations, plasma lactate concentrations, serum cortisol concentrations, heart rate, and rating of perceived exertion. Thus, a moderate dose of caffeine resulted in more total weight lifted for the chest press and a greater peak power attained during the Wingate test in competitive athletes.

Comparison of deep and superficial abdominal muscle activity between experienced Pilates and resistance exercise instructors and controls during stabilization exercise.

PubMed

Moon, Ji-Hyun; Hong, Sang-Min; Kim, Chang-Won; Shin, Yun-A

2015-06-01

Pilates and resistance exercises are used for lumbar stabilization training. However, it is unclear which exercise is more effective for lumbar stabilization. In our study, we aimed to compare surface muscle activity and deep muscle thickness during relaxation and spinal stabilization exercise in experienced Pilates and resistance exercise instructors. This study is a retrospective case control study set in the Exercise Prescription Laboratory and Sports Medicine Center. The participants included Pilates instructors (mean years of experience, 3.20±1.76; n=10), resistance exercise instructors (mean years of experience, 2.53±0.63; n=10), and controls (n=10). The participants performed 4 different stabilization exercises: abdominal drawing-in maneuver, bridging, roll-up, and one-leg raise. During the stabilization exercises, surface muscle activity was measured with electromyography, whereas deep muscle thickness was measured by ultrasound imaging. During the 4 stabilization exercises, the thickness of the transverse abdominis (TrA) was significantly greater in the Pilates-trained group than the other 2 other groups. The internal oblique (IO) thickness was significantly greater in the Pilates- and resistance-trained group than the control group, during the 4 exercises. However, the surface muscle activities were similar between the groups. Both Pilates and resistance exercise instructors had greater activation of deep muscles, such as the TrA and IO, than the control subjects. Pilates and resistance exercise are both effective for increasing abdominal deep muscle thickness.

Comparison of deep and superficial abdominal muscle activity between experienced Pilates and resistance exercise instructors and controls during stabilization exercise

PubMed Central

Moon, Ji-Hyun; Hong, Sang-Min; Kim, Chang-Won; Shin, Yun-A

2015-01-01

Pilates and resistance exercises are used for lumbar stabilization training. However, it is unclear which exercise is more effective for lumbar stabilization. In our study, we aimed to compare surface muscle activity and deep muscle thickness during relaxation and spinal stabilization exercise in experienced Pilates and resistance exercise instructors. This study is a retrospective case control study set in the Exercise Prescription Laboratory and Sports Medicine Center. The participants included Pilates instructors (mean years of experience, 3.20±1.76; n=10), resistance exercise instructors (mean years of experience, 2.53±0.63; n=10), and controls (n=10). The participants performed 4 different stabilization exercises: abdominal drawing-in maneuver, bridging, roll-up, and one-leg raise. During the stabilization exercises, surface muscle activity was measured with electromyography, whereas deep muscle thickness was measured by ultrasound imaging. During the 4 stabilization exercises, the thickness of the transverse abdominis (TrA) was significantly greater in the Pilates-trained group than the other 2 other groups. The internal oblique (IO) thickness was significantly greater in the Pilates- and resistance-trained group than the control group, during the 4 exercises. However, the surface muscle activities were similar between the groups. Both Pilates and resistance exercise instructors had greater activation of deep muscles, such as the TrA and IO, than the control subjects. Pilates and resistance exercise are both effective for increasing abdominal deep muscle thickness. PMID:26171383

Knee Brace Would Lock And Unlock Automatically

NASA Technical Reports Server (NTRS)

Myers, Neill; Forbes, John; Shadoan, Mike; Baker, Kevin

1995-01-01

Proposed knee brace designed to aid rehabilitation of person who suffered some muscle damage in leg. Not limited to locking in straight-leg position and, instead, locks at any bend angle. Does not prevent knee from bearing weight. Instead, knee brace allows knee to bear weight and locks only when foot and lower leg bear weight. Thus, brace prevents flexion that wearer desired to prevent but could not prevent because of weakened muscles. Knee bends freely to exercise knee-related muscles. Knee brace strapped at upper end to leg above knee, and anchored at lower end by stirrup under foot. Joint mechanism (identical mechanisms used in left and right assemblies) allows knee joint to flex freely except when weight applied to heel.

Exercise Versus +Gz Acceleration Training

NASA Technical Reports Server (NTRS)

Greenleaf, John E.; Simonson, S. R.; Stocks, J. M.; Evans, J. M.; Knapp, C. F.; Dalton, Bonnie P. (Technical Monitor)

2002-01-01

Decreased working capacity and "orthostatic" intolerance are two major problems for astronauts during and after landing from spaceflight in a return vehicle. The purpose was to test the hypotheses that (1) supine-passive-acceleration training, supine-interval-exercise plus acceleration training, and supine exercise plus acceleration training will improve orthostatic tolerance (OT) in ambulatory men; and that (2) addition of aerobic exercise conditioning will not influence this enhanced OT from that of passive-acceleration training. Seven untrained men (24-38 yr) underwent 3 training regimens (30 min/d x 5d/wk x 3wk on the human-powered centrifuge - HPC): (a) Passive acceleration (alternating +1.0 Gz to 50% Gzmax); (b) Exercise acceleration (alternating 40% - 90% V02max leg cycle exercise plus 50% of HPCmax acceleration); and (c) Combined intermittent exercise-acceleration at 40% to 90% HPCmax. Maximal supine exercise workloads increased (P < 0.05) by 8.3% with Passive, by 12.6% with Exercise, and by 15.4% with Combined; but maximal V02 and HR were unchanged in all groups. Maximal endurance (time to cessation) was unchanged with Passive, but increased (P < 0.05) with Exercise and Combined. Resting pre-tilt HR was elevated by 12.9% (P < 0.05) only after Passive training, suggesting that exercise training attenuated this HR response. All resting pre-tilt blood pressures (SBP, DBP, MAP) were not different pre- vs. post-training. Post-training tilt-tolerance time and HR were increased (P < 0.05) only with Passive training by 37.8% and by 29.1%, respectively. Thus, addition of exercise training attenuated the increased Passive tilt tolerance. Resting (pre-tilt) and post-tilt cardiac R-R interval, stroke volume, end-diastolic volume, and cardiac output were all uniformly reduced (P < 0.05) while peripheral resistance was uniformly increased (P < 0.05) pre-and post-training for the three regimens indicating no effect of any training regimen on those cardiovascular variables. Plasma volume (% delta) was uniformly decreased by 8% to 14% (P < 0.05) at tilt-tolerance pre- vs. post-training for all regimens indicating no effect of these training regimens on the level of vascular fluid shifts.

Symposium Conclusion: Women's cardiovascular health after bed rest or space flight

NASA Astrophysics Data System (ADS)

Hughson, Richard L.; Arbeille, Phillipe; Shoemaker, Kevin; Edgell, Heather

The Canadian Space Agency has recently funded research on two long-duration missions to study cardiovascular deconditioning associated with bed rest or space flight. The first, Women's International Space simulation for Exploration (WISE-2005) examined the responses during a 60-day head down bed rest (HDBR) of 24 women with or without a countermeasure that consisted of supine treadmill running within a lower body negative pressure (LBNP) device followed by 10-minutes resting LBNP and on different days high intensity resistance exercise on a flywheel device. The second study, Cardiovascular and cerebrovascular Control on return from the International Space Station (CCISS) is currently underway with two male astronauts tested and the first woman anticipated later this year. Women have been previously identified as being more susceptible to orthostatic intolerance than men after both bed rest and space flight studies. Thus, in the WISE-2005 study we examined responses of the cardiovascular system after HDBR in women and compared these to previously published data from men. We found that after HDBR women have a greater increase in heart rate with infusion of the drug isoproterenol and this was consistent with observations in men. However, during drug infusion the women had a reduction in leg vascular resistance while men had an increase. The exercise countermeasure group had preserved heart rate and leg vascular resistance responses to drug infusion. The ability to vasoconstrict the legs and splanchnic region is critical to maintenance of upright posture after HDBR and space flight. In the WISE-2005 study, subjects who were able to constrict the legs and/or splanchnic region after HDBR were much less likely to have a marked drop in blood pressure before the end of 10-minutes upright tilt, and subjects who performed the countermeasure were more likely to be in this group of tilt test finishers. These data provide new insight into mechanisms that might be responsible for fainting after bed rest or space flight, and they can be used to understand why specific populations such as the elderly might be more likely to faint during life on Earth. Supported by Canadian Space Agency.

Self-generating oscillating pressure exercise device

NASA Technical Reports Server (NTRS)

Watenpaugh, Donald E. (Inventor)

1994-01-01

An exercise device, especially suitable for zero gravity workouts, has a collapsible chamber which generates negative pressure on the lower portion of a body situated therein. The negative pressure is generated by virtue of leg, hand and shoulder interaction which contracts and expands the chamber about the person and by virtue of air flow regulation by valve action.

A prognostic scoring system for arm exercise stress testing.

PubMed

Xie, Yan; Xian, Hong; Chandiramani, Pooja; Bainter, Emily; Wan, Leping; Martin, Wade H

2016-01-01

Arm exercise stress testing may be an equivalent or better predictor of mortality outcome than pharmacological stress imaging for the ≥50% for patients unable to perform leg exercise. Thus, our objective was to develop an arm exercise ECG stress test scoring system, analogous to the Duke Treadmill Score, for predicting outcome in these individuals. In this retrospective observational cohort study, arm exercise ECG stress tests were performed in 443 consecutive veterans aged 64.1 (11.1) years. (mean (SD)) between 1997 and 2002. From multivariate Cox models, arm exercise scores were developed for prediction of 5-year and 12-year all-cause and cardiovascular mortality and 5-year cardiovascular mortality or myocardial infarction (MI). Arm exercise capacity in resting metabolic equivalents (METs), 1 min heart rate recovery (HRR) and ST segment depression ≥1 mm were the stress test variables independently associated with all-cause and cardiovascular mortality by step-wise Cox analysis (all p<0.01). A score based on the relation HRR (bpm)+7.3×METs-10.5×ST depression (0=no; 1=yes) prognosticated 5-year cardiovascular mortality with a C-statistic of 0.81 before and 0.88 after adjustment for significant demographic and clinical covariates. Arm exercise scores for the other outcome end points yielded C-statistic values of 0.77-0.79 before and 0.82-0.86 after adjustment for significant covariates versus 0.64-0.72 for best fit pharmacological myocardial perfusion imaging models in a cohort of 1730 veterans who were evaluated over the same time period. Arm exercise scores, analogous to the Duke Treadmill Score, have good power for prediction of mortality or MI in patients who cannot perform leg exercise.

Geotechnical Properties of Periplatform Carbonate Sediments

DTIC Science & Technology

1990-07-01

and Atmospheric and geoacoustic parameters for similar sediments in Research Laboratory participated in Ocean Drilling other regions. Leg 101. During...this exercise sha’"w-water and midwater depth carbonate sediments from a few deep drill holes were studied extensively by Results and Recommendations...protected by the grains and are less Deep Sea Drilling Project Leg 86. In: Heath, G. R., affected by consolidation than they are in matrix- Bruckle, L. H

Peripheral muscle ergoreceptors and ventilatory response during exercise recovery in heart failure.

PubMed

Francis, N; Cohen-Solal, A; Logeart, D

1999-03-01

Recent studies have suggested that the increased ventilatory response during exercise in patients with chronic heart failure was related to the activation of muscle metaboreceptors. To address this issue, 23 patients with heart failure and 7 normal subjects performed arm and leg bicycle exercises with and without cuff inflation around the arms or the thighs during recovery. Obstruction slightly reduced ventilation and gas exchange variables at recovery but did not change the kinetics of recovery of these parameters compared with nonobstructed recovery: half-time of ventilation recovery was 175 +/- 54 to 176 +/- 40 s in patients and 155 +/- 66 to 127 +/- 13 s in controls (P < 0.05, patients vs. controls, not significant within each group from baseline to obstructed recovery). We conclude that muscle metaboreceptor activation does not seem to play a role in the exertion hyperventilation of patients with heart failure.

Balance training reduces falls risk in older individuals with type 2 diabetes.

PubMed

Morrison, Steven; Colberg, Sheri R; Mariano, Mira; Parson, Henri K; Vinik, Arthur I

2010-04-01

This study assessed the effects of balance/strength training on falls risk and posture in older individuals with type 2 diabetes. Sixteen individuals with type 2 diabetes and 21 age-matched control subjects (aged 50-75 years) participated. Postural stability and falls risk was assessed before and after a 6-week exercise program. Diabetic individuals had significantly higher falls risk score compared with control subjects. The diabetic group also exhibited evidence of mild-to-moderate neuropathy, slower reaction times, and increased postural sway. Following exercise, the diabetic group showed significant improvements in leg strength, faster reaction times, decreased sway, and, consequently, reduced falls risk. Older individuals with diabetes had impaired balance, slower reactions, and consequently a higher falls risk than age-matched control subjects. However, all these variables improved after resistance/balance training. Together these results demonstrate that structured exercise has wide-spread positive effects on physiological function for older individuals with type 2 diabetes.

Superficial shell insulation in resting and exercising men in cold water.

PubMed

Veicsteinas, A; Ferretti, G; Rennie, D W

1982-06-01

From measurements of subcutaneous fat temperature (Tsf) at known depths below the surface, skin surface temperature (Tsk), and direct skin heat flux (H), the superficial shell isulation (Iss) of the thigh (fat + skin) was calculated as Iss (degrees C.m2.w-1) = (Tsf - Tsk)/H in nine male subjects immersed head out in a well-stirred water bath. Also, at critical water temperature (CWT = 28-33 degrees C), eight of the subjects rested for 3 h, enabling overall maximal tissue insulation (It,max) to be calculated as It,max (degrees C.m2.W-1) = (Tre - Tw)/(0.92 M +/- delta S), where Tre is rectal temperature, Tw is water temperature, M is metabolic rate, and s is loss or gain of body heat. Five subjects performed up to 2 h of mild leg cycling, preceded and followed by 60 min of rest, and both thigh Iss and overall It were measured during exercise. Iss increased from minimal values in Tw greater than 33 degrees C to maximal values (Iss,max) at CWT or below. Iss,max was linearly related to tissue thickness (d) in millimeters of fat plus skin, Iss,max (degrees C.m2.W-1) = 0.0048d-0.0052; r = 0.95, n = 37, and was not influenced by leg exercise up to a metabolic rate of 150 W.m-2 in CWT despite large increases in Tsf and H and large decreases in overall It. The slope of Iss,max vs. depth, 0.0048 degrees C.m2.W-1.mm-1, is almost identical to thermal resistivity of fat in vitro, suggesting that the superficial shell is unperfused in CWT at rest or during mild exercise. When maximal superficial shell insulation (It,ss,max) for the whole body was calculated with allowance for differing fat thicknesses and surface areas of body regions, it could account for only 10-15% of overall It,max at rest and 35-40% of overall It in mild exercise. We suggest that the poorly perfused muscle shell plays a more important role as a defense against cooling at CWT than does the superficial shell (fat + skin), particularly at rest.

Muscle blood flow at onset of dynamic exercise in humans.

PubMed

Rådegran, G; Saltin, B

1998-01-01

To evaluate the temporal relationship between blood flow, blood pressure, and muscle contractions, we continuously measured femoral arterial inflow with ultrasound Doppler at onset of passive exercise and voluntary, one-legged, dynamic knee-extensor exercise in humans. Blood velocity and inflow increased (P < 0.006) with the first relaxation of passive and voluntary exercise, whereas the arterial-venous pressure difference was unaltered [P = not significant (NS)]. During steady-state exercise, and with arterial pressure as a superimposed influence, blood velocity was affected by the muscle pump, peaking (P < 0.001) at approximately 2.5 +/- 0.3 m/s as the relaxation coincided with peak systolic arterial blood pressure; blood velocity decreased (P < 0.001) to 44.2 +/- 8.6 and 28.5 +/- 5.5% of peak velocity at the second dicrotic and diastolic blood pressure notches, respectively. Mechanical hindrance occurred (P < 0.001) during the contraction phase at blood pressures less than or equal to that at the second dicrotic notch. The increase in blood flow (Q) was characterized by a one-component (approximately 15% of peak power output), two-component (approximately 40-70% of peak power output), or three-component exponential model (> or = 75% of peak power output), where Q(t) = Qpassive + delta Q1.[1 - e-(t - TD1/tau 1)]+ delta Q2.[1 - e-(t - TD2/tau 2)]+ delta Q3.[1 - e-(t - TD3/tau 3)]; Qpassive, the blood flow during passive leg movement, equals 1.17 +/- 0.11 l/min; TD is the onset latency; tau is the time constant; delta Q is the magnitude of blood flow rise; and subscripts 1-3 refer to the first, second, and third components of the exponential model, respectively. The time to reach 50% of the difference between passive and voluntary asymptotic blood flow was approximately 2.2-8.9 s. The blood flow leveled off after approximately 10-150 s, related to the power outputs. It is concluded that the elevation in blood flow with the first duty cycle(s) is due to muscle mechanical factors, but vasodilators initiate a more potent amplification within the second to fourth contraction.

Acute and timing effects of beta-hydroxy-beta-methylbutyrate (HMB) on indirect markers of skeletal muscle damage.

PubMed

Wilson, Jacob M; Kim, Jeong-Su; Lee, Sang-Rok; Rathmacher, John A; Dalmau, Brett; Kingsley, J Derek; Koch, Heather; Manninen, Anssi H; Saadat, Raz; Panton, Lynn B

2009-02-04

While chronic β-Hydroxy β-Methylbutyrate (HMB) supplementation (≥ 2 wk) lowers exercise induced muscle damage, its acute or timing effects have not been examined. The purpose of this study was to investigate the acute and timing effects of oral HMB supplementation on serum creatine kinase (CK), lactate dehydrogenase (LDH), muscle soreness, and maximal voluntary contraction (MVC). Sixteen non-resistance trained men (22 ± 2 yrs) were assigned to HMB-Pre or HMB-Post groups. In a crossover design, all subjects performed 55 maximal eccentric knee extension/flexion contractions on 2 occasions on either the right or left leg. HMB-Pre (N = 8) randomly received 3 grams of either a placebo or HMB before and a placebo after exercise. HMB-Post (N = 8) received a placebo before and either 3 grams of HMB or a placebo after exercise. Muscle damage tests were recorded before, at 8, 24, 48, and 72 hrs post exercise. There was a reduction in MVC and an increase in soreness in the quadriceps and hamstrings following exercise (p < 0.001). Although HMB-Pre approached significance in attenuating soreness for the quadriceps (p = 0.07), there was no time x group effect. Serum indices of damage increased, peaking at 48 hrs for CK (773%) (p < 0.001) and 72 hrs for LDH (180%) (p < 0.001). While there were no time x group effects of HMB on CK and LDH, post hoc analysis revealed that only HMB-Pre showed no significant increase in LDH levels following exercise. Our findings suggest no clear acute or timing effects of HMB supplementation. However, consuming HMB before exercise appeared to prevent increases in LDH.

Acute and timing effects of beta-hydroxy-beta-methylbutyrate (HMB) on indirect markers of skeletal muscle damage

PubMed Central

Wilson, Jacob M; Kim, Jeong-su; Lee, Sang-rok; Rathmacher, John A; Dalmau, Brett; Kingsley, J Derek; Koch, Heather; Manninen, Anssi H; Saadat, Raz; Panton, Lynn B

2009-01-01

Background While chronic β-Hydroxy β-Methylbutyrate (HMB) supplementation (≥ 2 wk) lowers exercise induced muscle damage, its acute or timing effects have not been examined. The purpose of this study was to investigate the acute and timing effects of oral HMB supplementation on serum creatine kinase (CK), lactate dehydrogenase (LDH), muscle soreness, and maximal voluntary contraction (MVC). Methods Sixteen non-resistance trained men (22 ± 2 yrs) were assigned to HMB-Pre or HMB-Post groups. In a crossover design, all subjects performed 55 maximal eccentric knee extension/flexion contractions on 2 occasions on either the right or left leg. HMB-Pre (N = 8) randomly received 3 grams of either a placebo or HMB before and a placebo after exercise. HMB-Post (N = 8) received a placebo before and either 3 grams of HMB or a placebo after exercise. Muscle damage tests were recorded before, at 8, 24, 48, and 72 hrs post exercise. Results There was a reduction in MVC and an increase in soreness in the quadriceps and hamstrings following exercise (p < 0.001). Although HMB-Pre approached significance in attenuating soreness for the quadriceps (p = 0.07), there was no time × group effect. Serum indices of damage increased, peaking at 48 hrs for CK (773%) (p < 0.001) and 72 hrs for LDH (180%) (p < 0.001). While there were no time × group effects of HMB on CK and LDH, post hoc analysis revealed that only HMB-Pre showed no significant increase in LDH levels following exercise. Conclusion Our findings suggest no clear acute or timing effects of HMB supplementation. However, consuming HMB before exercise appeared to prevent increases in LDH. PMID:19193206

Blood pressure changes following aerobic exercise in Caucasian and Chinese descendants.

PubMed

Sun, P; Yan, H; Ranadive, S M; Lane, A D; Kappus, R M; Bunsawat, K; Baynard, T; Li, S; Fernhall, B

2015-03-01

Acute aerobic exercise produces post-exercise hypotension (PEH). Chinese populations have lower prevalence of cardiovascular disease compared to Caucasians. PEH may be associated cardiovascular disease through its influence on hypertension. The purpose of this study was to compare PEH between Caucasian and Chinese subjects following acute aerobic exercise. 62 (30 Caucasian and 32 Chinese, 50% male) subjects underwent measurement of peripheral and central hemodynamics as well as arterial and cardiac evaluations, 30 min and 60 min after 45 min of treadmill exercise. Caucasians exhibited significantly higher baseline BP than the Chinese. While the reduction in brachial artery systolic BP was greater in Caucasian than in the Chinese, there was no difference in changes in carotid systolic BP between the groups. The increase in cardiac output and heart rate was greater in the Chinese than Caucasians, but total peripheral resistance and leg pulse wave velocity decreased by a similar magnitude in the Chinese and Caucasian subjects. We conclude that acute aerobic exercise produces a greater magnitude of PEH in peripheral systolic BP in Caucasian compared to Chinese subjects. The different magnitude in PEH was caused by the greater increase in cardiac output mediated by heart rate, with no change in stroke volume. It is possible that initial BP differences between races influenced the findings. © Georg Thieme Verlag KG Stuttgart · New York.

Short-term effects of Theracurmin dose and exercise type on pain, walking ability, and muscle function in patients with knee osteoarthritis

PubMed Central

Shin, Yun-A; Suk, Min-Hwa; Jang, Hee-Seung; Choi, Hye-Jung

2017-01-01

The purpose of this study was to investigate the short-term of Theracurmin dose and exercise type on pain, walking ability, and muscle function in patients with knee osteoarthritis. Twenty-five patients with knee osteoarthritis randomly selected to Theracurmin intake (T) group and Theracurmin in combined with exercise (T+E) group. T group (n= 13) was taken orally a capsule of 700 mg, 3 times per day, (total 2,100 mg, 35 mg/kg-body weight). T+E group (n= 12) performed aerobic training of 30-min walking and weight training for increasing leg muscular strength. After treatment, the number of steps, muscle mass, range of motion of knee, and the muscle strength in flexion and extension significantly increased. The percent body fat, visual analogue scale, The Western Ontario and McMaster score, centers of pressure with closed eye, 10-m walking ability, stair ascending speed were significantly decreased after treatment. Although no difference observed between the T and T+E groups, the 4-week intake of Theracurmin with and without exercise appeared to be effective in reducing the pain and enhancing muscular and balancing function. Therefore, Theracurmin intake for early symptoms and additional exercise as symptoms alleviate might be an effective way of delaying and managing osteoarthritis, and additional studies investigating the effects of Theracurmin and exercise on osteoarthritis could be beneficial. PMID:29326901

Effects of home-based exercise on pre-dialysis chronic kidney disease patients: a randomized pilot and feasibility trial.

PubMed

Hiraki, Koji; Shibagaki, Yugo; Izawa, Kazuhiro P; Hotta, Chiharu; Wakamiya, Akiko; Sakurada, Tsutomu; Yasuda, Takashi; Kimura, Kenjiro

2017-06-17

Only a few research is available on the effects of home-based exercise training on pre-dialysis chronic kidney disease (CKD) patients. Therefore, we aimed to elucidate the effect of home-based exercise therapy on kidney function and arm and leg muscle strength in pre-dialysis CKD patients. Thirty-six male stage 3-4 pre-dialysis CKD patients (age, 68.7 ± 6.8 years; estimated glomerular filtration rate (eGFR), 39.0 ± 11.6 ml/min/1.73 m 2 ) who were being treated as outpatients were included. The subjects were randomly assigned to an exercise intervention group (Ex group: 18) and a control group (C group: 18). The Ex group wore accelerometer pedometers and were instructed to perform home-based aerobic and resistance exercises, such as brisk walking for 30 min per day, for 12 months. The C group subjects wore accelerometer pedometers but received no exercise therapy guidance; the number of steps covered during normal daily activities was recorded for the C group. The outcome measures were changes in kidney function and handgrip and knee extension muscle strength. Values at the baseline (T1) and 12 months later (T2) were compared. There were no significant differences in baseline characteristics between the two groups; however, the C group was more physically active than the Ex group. Eight subjects dropped out, and 28 subjects (14 in each group) were included in the final analysis. Physical activity increased significantly only in the Ex group. Grip strength (F = 7.0, p = 0.01) and knee extension muscle strength (F = 14.3, p < 0.01) were found to improve only in the Ex group. Further, the changes in eGFR were not significantly different between the two groups (F = 0.01, p = 0.93). Home-based exercise therapy for pre-dialysis CKD patients was feasible and improved arm and leg muscle strength without affecting kidney function. UMIN Clinical Trials Registry ( UMIN000005091 ). Registered 2/15/2011.

Comparing exercise responses to aerobic plus resistance training between postmenopausal breast cancer survivors undergoing aromatase inhibitor therapy and healthy women.

PubMed

Paulo, Thais R S de; Winters-Stone, Kerri M; Viezel, Juliana; Rossi, Fabricio E; Aro, Bruna L; Trindade, Ana Carolina A C; Codogno, Jamile S; Freitas Junior, Ismael F

2018-04-12

The aim of this study was to explore whether postmenopausal breast cancer survivors undergoing aromatase inhibitor therapy differ from healthy postmenopausal women in their response to the same aerobic + resistance training. The participants were separated into two groups: postmenopausal breast cancer survivors undergoing aromatase inhibitor therapy for an average of 20 months (18 women) and healthy postmenopausal women (24 women). We assessed aerobic capacity (predicted maximum oxygen uptake (VO 2 max) and maximum running velocity test (Vmax)) through a walking test, upper and lower body muscle strength using an estimated one-repetition maximum test, and body composition by dual-energy X-ray absorptiometry at baseline and at three, six, and nine months, respectively. The exercise program was performed three times/week over nine months and consisted of 40 min of machine-based strength training (seated cable row, bench press, leg extension, leg press, and leg curl, as well as bridge, abdominal, and standard plank exercises) followed by 30 min of treadmill walking. Analysis of variance (ANOVA) with repeated measures was used to compare the groups over time. Postmenopausal breast cancer survivors undergoing aromatase inhibitor therapy and healthy postmenopausal women presented similar improvements in estimated lower body strength, predicted VO 2max and V max , and body fat mass. For maximal upper body strength, there was a significant group x time interaction after six months of training (p = 0.01). The healthy postmenopausal women presented a significant increase in upper body strength after six months, while postmenopausal breast cancer survivors undergoing aromatase inhibitor therapy demonstrated an improvement only at nine months of training. The breast cancer survivors undergoing aromatase inhibitor therapy presented increased lean mass while healthy postmenopausal women maintained values over time (Breast cancer: 33.7 ± 3.9(Pre) vs. 34.1 ± 3.4 kg (Post) and healthy women: 36.4 ± 5.1 (Pre) vs. 36.4 ± 5.0 kg (Post), p = 0.004). Our findings suggest that postmenopausal women undergoing aromatase inhibitor therapy for breast cancer demonstrated adaptations and similar trainability to the same regimen of resistance + aerobic training as healthy postmenopausal women. Implications for Rehabilitation Combined exercise program (aerobic plus resistance) is an important non-pharmacological strategies to improve strength, aerobic capacity, and body composition in breast cancer survivors undergoing aromatase inhibitor therapy. Furthermore, it is important to highlight that the time of intervention seems to influence the upper body strength response in this population. This study showed that trainers and other specialists do not need to modify the prescription of exercise related to healthy women, since the combined exercise program induced similar benefits in strength, aerobic capacity, and body composition in postmenopausal breast cancer survivors undergoing aromatase inhibitor therapy and healthy postmenopausal women.

Exercise countermeasures for bed-rest deconditioning

NASA Technical Reports Server (NTRS)

Greenleaf, John (Editor)

1993-01-01

The purpose for this 30-day bed rest study was to investigate the effects of short-term, high intensity isotonic and isokinetic exercise training on maintenance of working capacity (peak oxygen uptake), muscular strength and endurance, and on orthostatic tolerance, posture and gait. Other data were collected on muscle atrophy, bone mineralization and density, endocrine analyses concerning vasoactivity and fluid-electrolyte balance, muscle intermediary metabolism, and on performance and mood of the subjects. It was concluded that: The subjects maintained a relatively stable mood, high morale, and high esprit de corps throughout the study. Performance improved in nearly all tests in almost all the subjects. Isotonic training, as opposed to isokinetic exercise training, was associated more with decreasing levels of psychological tension, concentration, and motivation; and improvement in the quality of sleep. Working capacity (peak oxygen uptake) was maintained during bed rest with isotonic exercise training; it was not maintained with isokinetic or no exercise training. In general, there was no significant decrease in strength or endurance of arm or leg muscles during bed rest, in spite of some reduction in muscle size (atrophy) of some leg muscles. There was no effect of isotonic exercise training on orthostasis, since tilt-table tolerance was reduced similarly in all three groups following bed rest. Bed rest resulted in significant decreases of postural stability and self-selected step length, stride length, and walking velocity, which were not influenced by either exercise training regimen. Most pre-bed rest responses were restored by the fourth day of recovery.

The Effect of Aquatic Exercise Therapy on Muscle Strength and Joint's Range of Motion in Hemophilia Patients.

PubMed

Kargarfard, Mehdi; Dehghadani, Mehdi; Ghias, Reza

2013-01-01

This study was to evaluate the effect of a period of aquatic exercise therapy on muscle strength and joints range of motion in hemophilia patients. This was a semiexperimental, pretest, post-test study with a control group. This semi-experimental study comprised twenty men suffering moderate hemophilia were selected by convenience sampling method from patients of a referral hospital. They were randomly assigned to intervention and control groups of equal number. The hemophilia patients who were referred to Sayedo-Shohada Hospital enrolled in this study. Twenty men suffering moderate hemophilia were selected using convenience sampling method and then divided randomly into intervention and control groups (10 patients in each group). Subjects of aquatic exercise therapy group underwent activity in water in three sessions (45-60 minutes) per week for 8 weeks, while the control group was only under follow-up and during this period did not experience any effective physical activity. The patients' muscle strength and joint range of motion were evaluated through standard laboratory tools, using an isokinetic dynamometer (Biodex, Systems III) and a standard goniometer in the beginning and at end of the study. Finally, data was analyzed using analysis of covariance (ANCOVA). The strength of the muscles around the knee joint (to perform extension and flexion movements) increased significantly in the case group while the control group experienced a significant reduction of strength in left leg, but in right leg remarkable change was observed. Range of motion in all joints was improved in the case group, while the control group did not improve significantly. The results showed that aquatic exercise therapy can be a useful method to improve joints' strength and range of motion in hemophilia patients in order to improve their daily functioning and quality of life.

High-Intensity Interval Training and Isocaloric Moderate-Intensity Continuous Training Result in Similar Improvements in Body Composition and Fitness in Obese Individuals.

PubMed

Martins, Catia; Kazakova, Irina; Ludviksen, Marit; Mehus, Ingar; Wisloff, Ulrik; Kulseng, Bard; Morgan, Linda; King, Neil

2016-06-01

This study aimed to determine the effects of 12 weeks of isocaloric programs of high-intensity intermittent training (HIIT) or moderate-intensity continuous training (MICT) or a short-duration HIIT (1/2HIIT) inducing only half the energy deficit on a cycle ergometer, on body weight and composition, cardiovascular fitness, resting metabolism rate (RMR), respiratory exchange ratio (RER), nonexercise physical activity (PA) levels and fasting and postprandial insulin response in sedentary obese individuals. Forty-six sedentary obese individuals (30 women), with a mean BMI of 33.3 ± 2.9 kg/m2 and a mean age of 34.4 ± 8.8 years were randomly assigned to one of the three training groups: HIIT (n = 16), MICT (n = 14) or 1/2HIIT (n = 16) and exercise was performed 3 times/week for 12 weeks. Overall, there was a significant reduction in body weight, waist (p < .001) and hip (p < .01) circumference,, trunk and leg fat mass (FM; p < .01) and an increase in trunk and leg fat free mass (FFM; p < .01) and cardiovascular fitness (VO2max in ml/kg/min; p < .001) with exercise. However, no significant differences were observed between groups. There was no significant change in RMR, RER, nonexercise PA levels, fasting insulin or insulin sensitivity with exercise or between groups. There was a tendency for a reduction in AUC insulin with exercise (p = .069), but no differences between groups. These results indicate that isocaloric training protocols of HIIT or MICT (or 1/2HIIT inducing only half the energy deficit) exert similar metabolic and cardiovascular improvements in sedentary obese individuals.

Effects of hybrid cycling versus handcycling on wheelchair-specific fitness and physical activity in people with long-term spinal cord injury: a 16-week randomized controlled trial.

PubMed

Bakkum, A J T; de Groot, S; Stolwijk-Swüste, J M; van Kuppevelt, D J; van der Woude, L H V; Janssen, T W J

2015-05-01

This is an open randomized controlled trial. The objective of this study was to investigate the effects of a 16-week hybrid cycle versus handcycle exercise program on fitness and physical activity in inactive people with long-term spinal cord injury (SCI). The study was conducted in two rehabilitation centers with a specialized SCI unit. Twenty individuals (SCI⩾8 years) were randomly assigned to a hybrid cycle (voluntary arm exercise combined with functional electrical stimulation (FES)-induced leg exercise) or a handcycle group. During 16 weeks, both groups trained twice a week for 30 min at 65-75% heart rate reserve. Outcome measures obtained before, during and after the program were fitness (peak power output, peak oxygen consumption), submaximal VO2 and heart rate (HR), resting HR, wheelchair skill performance time score) and physical activity (distance travelled in wheelchair and Physical Activity Scale for Individuals with Physical Disabilities (PASIPD) score). Changes were examined using a two-factor mixed-measures analysis of variance. For all fitness parameters, except for submaximal VO2, no interaction effects were found. The hybrid cycle group showed a decrease in VO2 over time in contrast to the handcycle group (P=0.045). An overall reduction in HRrest (5±2 b.p.m.; P=0.03) and overall increase in PASIPD score (6.5±2.1; P=0.002) were found after 16 weeks of training. No overall training effects were found for the other fitness and activity outcome measures. In the current study, hybrid cycling and handcycling showed similar effects on fitness and physical activity, indicating that there seem to be no additional benefits of the FES-induced leg exercise over handcycle training alone.

Squeezing the muscle: compression clothing and muscle metabolism during recovery from high intensity exercise.

PubMed

Sperlich, Billy; Born, Dennis-Peter; Kaskinoro, Kimmo; Kalliokoski, Kari K; Laaksonen, Marko S

2013-01-01

The purpose of this experiment was to investigate skeletal muscle blood flow and glucose uptake in m. biceps (BF) and m. quadriceps femoris (QF) 1) during recovery from high intensity cycle exercise, and 2) while wearing a compression short applying ~37 mmHg to the thigh muscles. Blood flow and glucose uptake were measured in the compressed and non-compressed leg of 6 healthy men by using positron emission tomography. At baseline blood flow in QF (P = 0.79) and BF (P = 0.90) did not differ between the compressed and the non-compressed leg. During recovery muscle blood flow was higher compared to baseline in both compressed (P<0.01) and non-compressed QF (P<0.001) but not in compressed (P = 0.41) and non-compressed BF (P = 0.05; effect size = 2.74). During recovery blood flow was lower in compressed QF (P<0.01) but not in BF (P = 0.26) compared to the non-compressed muscles. During baseline and recovery no differences in blood flow were detected between the superficial and deep parts of QF in both, compressed (baseline P = 0.79; recovery P = 0.68) and non-compressed leg (baseline P = 0.64; recovery P = 0.06). During recovery glucose uptake was higher in QF compared to BF in both conditions (P<0.01) with no difference between the compressed and non-compressed thigh. Glucose uptake was higher in the deep compared to the superficial parts of QF (compression leg P = 0.02). These results demonstrate that wearing compression shorts with ~37 mmHg of external pressure reduces blood flow both in the deep and superficial regions of muscle tissue during recovery from high intensity exercise but does not affect glucose uptake in BF and QF.

Non-invasive ventilation during cycle exercise training in patients with chronic respiratory failure on long-term ventilatory support: A randomized controlled trial.

PubMed

Vitacca, Michele; Kaymaz, Dicle; Lanini, Barbara; Vagheggini, Guido; Ergün, Pınar; Gigliotti, Francesco; Ambrosino, Nicolino; Paneroni, Mara

2018-02-01

The role of non-invasive ventilation (NIV) during exercise training (ET) in patients with chronic respiratory failure (CRF) is still unclear. The aim of this study was to test whether NIV during ET had an additional effect in increasing the 6-min walking distance (6MWD) and cycle endurance time compared with ET alone. All patients underwent 20 sessions of cycle training over 3 weeks and were randomly assigned to ET with NIV or ET alone. Outcome measures were 6MWD (primary outcome), incremental and endurance cycle ergometer exercise time, respiratory muscle function, quality of life by the Maugeri Respiratory Failure questionnaire (MRF-28), dyspnoea (Medical Research Council scale) and leg fatigue at rest. Forty-two patients completed the study. Following training, no significant difference in 6MWD changes were found between groups. Improvement in endurance time was significantly greater in the NIV group compared with the non-NIV training group (754 ± 973 vs 51 ± 406 s, P = 0.0271); dyspnoea improved in both groups, while respiratory muscle function and leg fatigue improved only in the NIV ET group. MRF-28 improved only in the group training without NIV. In CRF patients on long-term NIV and long-term oxygen therapy (LTOT), the addition of NIV to ET sessions resulted in an improvement in endurance time, but not in 6MWD. © 2017 Asian Pacific Society of Respirology.

Anthropometry as a predictor of high speed performance.

PubMed

Caruso, J F; Ramey, E; Hastings, L P; Monda, J K; Coday, M A; McLagan, J; Drummond, J

2009-07-01

To assess anthropometry as a predictor of high-speed performance, subjects performed four seated knee- and hip-extension workouts with their left leg on an inertial exercise trainer (Impulse Technologies, Newnan GA). Workouts, done exclusively in either the tonic or phasic contractile mode, entailed two one-minute sets separated by a 90-second rest period and yielded three performance variables: peak force, average force and work. Subjects provided the following anthropometric data: height, weight, body mass index, as well as total, upper and lower left leg lengths. Via multiple regression, anthropometry attempted to predict the variance per performance variable. Anthropometry explained a modest (R2=0.27-0.43) yet significant degree of variance from inertial exercise trainer workouts. Anthropometry was a better predictor of peak force variance from phasic workouts, while it accounted for a significant degree of average force and work variance solely from tonic workouts. Future research should identify variables that account for the unexplained variance from high-speed exercise performance.

Shin splints - self-care

MedlinePlus

... self-care; Tibial periostitis - self-care; Posterior tibial shin splints - self-care ... Shin splints are an exercise problem. You get shin splints from overloading your leg muscles, tendons or shin ...

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.

Human skeletal muscle glycogen utilization in exhaustive exercise: role of subcellular localization and fibre type

PubMed Central

Nielsen, Joachim; Holmberg, Hans-Christer; Schrøder, Henrik D; Saltin, Bengt; Ørtenblad, Niels

2011-01-01

Abstract Although glycogen is known to be heterogeneously distributed within skeletal muscle cells, there is presently little information available about the role of fibre types, utilization and resynthesis during and after exercise with respect to glycogen localization. Here, we tested the hypothesis that utilization of glycogen with different subcellular localizations during exhaustive arm and leg exercise differs and examined the influence of fibre type and carbohydrate availability on its subsequent resynthesis. When 10 elite endurance athletes (22 ± 1 years, = 68 ± 5 ml kg−1 min−1, mean ± SD) performed one hour of exhaustive arm and leg exercise, transmission electron microscopy revealed more pronounced depletion of intramyofibrillar than of intermyofibrillar and subsarcolemmal glycogen. This phenomenon was the same for type I and II fibres, although at rest prior to exercise, the former contained more intramyofibrillar and subsarcolemmal glycogen than the latter. In highly glycogen-depleted fibres, the remaining small intermyofibrillar and subsarcolemmal glycogen particles were often found to cluster in groupings. In the recovery period, when the athletes received either a carbohydrate-rich meal or only water the impaired resynthesis of glycogen with water alone was associated primarily with intramyofibrillar glycogen. In conclusion, after prolonged high-intensity exercise the depletion of glycogen is dependent on subcellular localization. In addition, the localization of glycogen appears to be influenced by fibre type prior to exercise, as well as carbohydrate availability during the subsequent period of recovery. These findings provide insight into the significance of fibre type-specific compartmentalization of glycogen metabolism in skeletal muscle during exercise and subsequent recovery. PMID:21486810

Does intermittent pneumatic leg compression enhance muscle recovery after strenuous eccentric exercise?

PubMed

Cochrane, D J; Booker, H R; Mundel, T; Barnes, M J

2013-11-01

Intermittent pneumatic compression (IPC) has gained rapid popularity as a post-exercise recovery modality. Despite its widespread use and anecdotal claims for enhancing muscle recovery there is no scientific evidence to support its use. 10 healthy, active males performed a strenuous bout of eccentric exercise (3 sets of 100 repetitions) followed by IPC treatment or control performed immediately after exercise and at 24 and 48 h post-exercise. Muscular performance measurements were taken prior to exercise and 24, 48 and 72 h post-exercise and included single-leg vertical jump (VJ) and peak and average isometric [knee angle 75º] (ISO), concentric (CON) and eccentric (ECC) contractions performed at slow (30° · s⁻¹) and fast (180° · s⁻¹) velocities. Plasma creatine kinase (CK) samples were taken at pre- and post-exercise 24, 48 and 72 h. Strenuous eccentric exercise resulted in a significant decrease in peak ISO, peak and average CON (30° · s⁻¹) at 24 h compared to pre-exercise for both IPC and control, however VJ performance remained unchanged. There were no significant differences between conditions (IPC and control) or condition-time interactions for any of the contraction types (ISO, CON, ECC) or velocities (CON, ECC 30° · s⁻¹ and 180° · s⁻¹). However, CK was significantly elevated at 24 h compared to pre-exercise in both conditions (IPC and control). IPC did not attenuate muscle force loss following a bout of strenuous eccentric exercise in comparison to a control. While IPC has been used in the clinical setting to treat pathologic conditions, the parameters used to treat muscle damage following strenuous exercise in healthy participants are likely to be very different than those used to treat pathologic conditions. © Georg Thieme Verlag KG Stuttgart · New York.

Low-Load High Volume Resistance Exercise Stimulates Muscle Protein Synthesis More Than High-Load Low Volume Resistance Exercise in Young Men

PubMed Central

Burd, Nicholas A.; West, Daniel W. D.; Staples, Aaron W.; Atherton, Philip J.; Baker, Jeff M.; Moore, Daniel R.; Holwerda, Andrew M.; Parise, Gianni; Rennie, Michael J.; Baker, Steven K.; Phillips, Stuart M.

2010-01-01

Background We aimed to determine the effect of resistance exercise intensity (% 1 repetition maximum—1RM) and volume on muscle protein synthesis, anabolic signaling, and myogenic gene expression. Methodology/Principal Findings Fifteen men (21±1 years; BMI = 24.1±0.8 kg/m2) performed 4 sets of unilateral leg extension exercise at different exercise loads and/or volumes: 90% of repetition maximum (1RM) until volitional failure (90FAIL), 30% 1RM work-matched to 90%FAIL (30WM), or 30% 1RM performed until volitional failure (30FAIL). Infusion of [ring-13C6] phenylalanine with biopsies was used to measure rates of mixed (MIX), myofibrillar (MYO), and sarcoplasmic (SARC) protein synthesis at rest, and 4 h and 24 h after exercise. Exercise at 30WM induced a significant increase above rest in MIX (121%) and MYO (87%) protein synthesis at 4 h post-exercise and but at 24 h in the MIX only. The increase in the rate of protein synthesis in MIX and MYO at 4 h post-exercise with 90FAIL and 30FAIL was greater than 30WM, with no difference between these conditions; however, MYO remained elevated (199%) above rest at 24 h only in 30FAIL. There was a significant increase in AktSer473 at 24h in all conditions (P = 0.023) and mTORSer2448 phosphorylation at 4 h post-exercise (P = 0.025). Phosporylation of Erk1/2Tyr202/204, p70S6KThr389, and 4E-BP1Thr37/46 increased significantly (P<0.05) only in the 30FAIL condition at 4 h post-exercise, whereas, 4E-BP1Thr37/46 phosphorylation was greater 24 h after exercise than at rest in both 90FAIL (237%) and 30FAIL (312%) conditions. Pax7 mRNA expression increased at 24 h post-exercise (P = 0.02) regardless of condition. The mRNA expression of MyoD and myogenin were consistently elevated in the 30FAIL condition. Conclusions/Significance These results suggest that low-load high volume resistance exercise is more effective in inducing acute muscle anabolism than high-load low volume or work matched resistance exercise modes. PMID:20711498

Effects of a salsa dance training on balance and strength performance in older adults.

PubMed

Granacher, Urs; Muehlbauer, Thomas; Bridenbaugh, Stephanie A; Wolf, Madeleine; Roth, Ralf; Gschwind, Yves; Wolf, Irene; Mata, Rui; Kressig, Reto W

2012-01-01

Deficits in static and particularly dynamic postural control and force production have frequently been associated with an increased risk of falling in older adults. The objectives of this study were to investigate the effects of salsa dancing on measures of static/dynamic postural control and leg extensor power in seniors. Twenty-eight healthy older adults were randomly assigned to an intervention group (INT, n = 14, age 71.6 ± 5.3 years) to conduct an 8-week progressive salsa dancing programme or a control group (CON, n = 14, age 68.9 ± 4.7 years). Static postural control was measured during one-legged stance on a balance platform and dynamic postural control was obtained while walking on an instrumented walkway. Leg extensor power was assessed during a countermovement jump on a force plate. Programme compliance was excellent with participants of the INT group completing 92.5% of the dancing sessions. A tendency towards an improvement in the selected measures of static postural control was observed in the INT group as compared to the CON group. Significant group × test interactions were found for stride velocity, length and time. Post hoc analyses revealed significant increases in stride velocity and length, and concomitant decreases in stride time. However, salsa dancing did not have significant effects on various measures of gait variability and leg extensor power. Salsa proved to be a safe and feasible exercise programme for older adults accompanied with a high adherence rate. Age-related deficits in measures of static and particularly dynamic postural control can be mitigated by salsa dancing in older adults. High physical activity and fitness/mobility levels of our participants could be responsible for the nonsignificant findings in gait variability and leg extensor power. Copyright © 2012 S. Karger AG, Basel.

Lack of age-specific influence on leg blood flow during incremental calf plantar-flexion exercise in men and women.

PubMed

Reilly, Heather; Lane, Louise M; Egaña, Mikel

2018-05-01

Age-related exercising leg blood flow (LBF) responses during dynamic knee-extension exercise and forearm blood flow responses during handgrip exercise are preserved in normally active men but attenuated in activity-matched women. We explored whether these age- and sex-specific effects are also apparent during isometric calf plantar-flexion incremental exercise. Normally active young men (YM, n = 15, 24 ± 2 years), young women (YW, n = 8, 22 ± 1 years), older men (OM, n = 13, 70 ± 7 years) and older women (OW, n = 10, 64 ± 7 years) were tested. LBF was measured between contractions using venous occlusion plethysmography. Peak force obtained was higher (P < 0.05) in men compared with women and in young compared with older individuals. However, peak LBF (YM; 971 ± 328 ml min -1 , OM; 985 ± 504 ml min -1 , YW; 844 ± 366 ml min -1 , OW; 960 ± 244 ml min -1 ) and peak leg vascular conductance [LVC = LBF/(MAP + hydrostatic pressure)] responses (YM; 6.0 ± 1.8 ml min -1  mmHg -1 , OM; 5.5 ± 2.8 ml min -1  mmHg -1 , YW; 5.3 ± 2.1 ml min -1  mmHg -1 , OW; 5.5 ± 1.6 ml min -1 mmHg -1 ) were similar among the four groups. Furthermore, the hyperaemic (YM; 8.8 ± 3.7 ml min -1  %F peak -1 OM; 8.3 ± 5.4 ml min -1  %F peak -1 , YW; 8.2 ± 3.5 ml min -1  %F peak -1 , OW; 9.6 ± 2.2 ml min -1  %F peak -1 ) and vasodilatory responses (YM; 0.053 ± 0.020 ml min -1  mmHg -1  %F peak -1 , OM; 0.048 ± 0.028 ml min -1  mmHg -1  %F peak -1 , YW; 0.051 ± 0.019 ml min -1  mmHg -1  %F peak -1 , OW; 0.055 ± 0.014 ml min -1  mmHg -1  %F peak -1 ) were not different among the four groups. These results were accompanied by similar resting LBF responses among groups and were not affected when data were normalised to estimated leg muscle mass. Our results demonstrate that exercising LBF responses during isometric incremental calf muscle exercise are preserved in older men and women, suggesting that the previously observed age-related attenuations in leg and forearm hyperaemia among women may be muscle-group specific.

The Relationship Between Lower Limb Bone and Muscle in Military Recruits, Response to Physical Training, and Influence of Smoking Status

PubMed Central

Puthucheary, Zudin; Kordi, Mehdi; Rawal, Jai; Eleftheriou, Kyriacos I.; Payne, John; Montgomery, Hugh E.

2015-01-01

The relationship between bone and skeletal muscle mass may be affected by physical training. No studies have prospectively examined the bone and skeletal muscle responses to a short controlled exercise-training programme. We hypothesised that a short exercise-training period would affect muscle and bone mass together. Methods: Femoral bone and Rectus femoris Volumes (RFVOL) were determined by magnetic resonance imaging in 215 healthy army recruits, and bone mineral density (BMD) by Dual X-Ray Absorptiometry (DXA) and repeated after 12 weeks of regulated physical training. Results: Pre-training, RFVOL was smaller in smokers than non-smokers (100.9 ± 20.2 vs. 108.7 ± 24.5, p = 0.018; 96.2 ± 16.9 vs. 104.8 ± 21.3, p = 0.002 for dominant/non-dominant limbs), although increases in RFVOL with training (of 14.2 ± 14.5% and 13.2 ± 15.6%] respectively, p < 0.001) were independent of prior smoking status. Pre-training RFVOL was related to bone cortical volume (r2 = 0.21 and 0.30, p < 0.001 for dominant and non-dominant legs), and specifically to periosteal (r2 = 0.21 and 0.23, p < 0.001) volume. Pre-training dominant RFVOL was independently associated with Total Hip BMD (p < 0.001). Training-related increases in RFVOL and bone volumes were related. Whilst smokers demonstrated lower muscle mass than non-smokers, differences were abolished with training. Training-related increases in muscle mass were related to increases in periosteal bone volume in both dominant and non-dominant legs. PMID:25792356

[Traveler's thrombosis].

PubMed

Riedel, M; Bohanes, V

2002-08-01

It is pathophysiologically conceivable that prolonged sitting in a tight space (e.g., in airplane or other transport vehicle) may lead to leg vein thrombosis. The association between the incidence of venous thromboembolism and long travel has not been sufficiently documented but seems probable. However, this association is only weak and the incidence of symptomatic thromboembolism much lower than the impression given by the recent publicity. In a healthy person, the risk of suffering a clinically relevant leg vein thrombosis solely because of a flight is extreme low. In persons with risk factors for venous thromboembolism, the flight represents an additional, as yet not quantifiable risk. This risk increases with the duration of the travel. The most important cause of thrombosis during long journeys seems to be venostasis due to relative immobilization. It is not clear whether flight travel represents a higher risk of thrombosis compared to other transport vehicles with comparable duration and immobilization. Until more exact information becomes available, it seems reasonable to recommend simple isometric and isotonic leg exercises during long travel. More aggressive measures must be considered for persons with risk factors for thromboembolism, but these measures should be individualized.

Day-to-Day Changes in Muscle Protein Synthesis in Recovery From Resistance, Aerobic, and High-Intensity Interval Exercise in Older Men.

PubMed

Bell, Kirsten E; Séguin, Christopher; Parise, Gianni; Baker, Steven K; Phillips, Stuart M

2015-08-01

Resistance exercise (RE) and aerobic exercise are recommended for older adults for fitness and strength. High-intensity interval exercise (HIIT) is an understudied but potent potential alternative to aerobic exercise. This study aimed to determine how each mode of exercise affected the integrated day-to-day response of muscle protein synthesis. Sedentary men (n = 22; 67±4 years; body mass index: 27.0±2.6 kg m(-) (2) [mean ± SEM]) were randomly assigned to perform RE, aerobic exercise, or HIIT. Participants consumed a stable isotope tracer (D2O) for 9 days. Daily saliva samples were taken to measure tracer incorporation in body water. Muscle biopsies were obtained on Days 5-8 of D2O consumption to measure tracer incorporation into muscle at rest, 24 hours, and 48 hours following each exercise bout: RE (3 × 10 repetitions: leg extensor and press, 95% 10RM), HIIT (10 × 1 minute, 95% maximal heart rate [HRmax]), or aerobic exercise (30 minutes, 55%-60% HRmax). Myofibrillar protein fractional synthetic rate was elevated, relative to rest, at 24 and 48 hours following RE and HIIT. The increase in myofibrillar fractional synthetic rate was greater following RE versus HIIT at both time points. HIIT was the only mode of exercise to increase sarcoplasmic protein fractional synthetic rate 24-hour postexercise (2.30±0.34% d(-) (1) vs 1.83±0.21% d(-) (1)). This study shows that in older men, changes in muscle protein synthesis in response to certain exercises are long lasting and that HIIT significantly increases myofibrillar and sarcoplasmic fractional synthetic rate in this population. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Analysis of sub-bandage pressure of compression bandages during exercise.

PubMed

Kumar, B; Das, A; Alagirusamy, R

2012-11-01

The sub-bandage pressure produced by any compression bandaging system is likely to vary during the physical activities taken by the patient. It is of significant importance to understand the variation of sub-bandage pressure during the exercise of calf muscle pump. The present paper aims to analyse the dominating factors and their interactions on the sub-bandage pressure during exercise. In this work the circumferential change of the leg because of the exercise of the calf muscle pump (expansion or contraction) is simulated using expansion or contraction actions of an air bladder placed on a mannequin. The study has been carried out using an indigenously developed prototype by pumping or squeezing of air in air bladder using cylinder-piston arrangement. A series of commercially available bandages were studied and the impact of the major factors, namely bandage extensibility (E), bandage tension (T) and the amount of bladder expansion or contraction (A) on the sub-bandage pressure during one cycle of expansion or contraction of air bladder have been analysed. Different levels of the factors have been chosen and a complete factorial design was prepared to obtain the sub-bandage pressure at all combination of the levels of the factors. The results showed that the sub-bandage pressure variations were higher for short-stretch bandage under dynamic mode (p value < 0.05). The variation in sub-bandage pressure were increased by increasing the amount of expansion or contraction of the air bladder and also increased when the bandage was wrapped at higher tension level (p-value < 0.05). N-way ANOVA results showed that some of the interactions effects of these above factors (EA and AT) also significantly affecting the sub-bandage pressure variations (p-value < 0.05). The prototype provides a simpler method to assess the bandage behaviour under different conditions without doing in vivo sub-bandage pressure measurement, and hence could be used to evaluate and compare the effectiveness of different compression bandage under different conditions, prior to their application on the wounded leg. Copyright © 2012 Tissue Viability Society. Published by Elsevier Ltd. All rights reserved.

Hypovolemic intolerance to lower body negative pressure in female runners.

PubMed

Morikawa, T; Sagawa, S; Torii, R; Endo, Y; Yamazaki, F; Shiraki, K

2001-12-01

An attenuated baroreflex response and orthostatic intolerance have been reported in endurance-trained male athletes; however, it is still unknown whether this occurs also in females. The purpose of the present study was to examine whether endurance exercise-trained women had a predisposition to orthostatic compromise, and if so, what causative factor(s) may induce orthostatic intolerance. We studied cardiovascular and hormonal responses to graded lower body negative pressure (LBNP) (0 to -60 mm Hg) in 26 middle-distance female runners (18.6 +/- 0.1 yr) as the exercise-trained (ET) subjects and 23 age-matched untrained (UT) control subjects. On the basis of the occurrence of syncope episodes during LBNP, ET and UT subjects were further allocated to two groups; ET with presyncope (ET+syncope) and without presyncope (ET-syncope) and UT with presyncope (UT+syncope) and without presyncope (UT-syncope). Occurrence of presyncope episodes during LBNP was higher in ET (65.4%, P < 0.05) than that for UT (34.8%). Leg compliance was higher (P < 0.05) in ET than in UT. LBNP reduced stroke volume (SV) more (P < 0.05), increased heart rate (HR) higher (P < 0.05), and increased forearm vascular resistance (FVR) more in ET+syncope as compared with the other groups. Response of vasoactive hormones to LBNP was higher in ET+syncope (P < 0.05) than that of the other groups except for norepinephrine (NE); high in both ET+syncope and UT+syncope. The relationship between SV and NE, an index of sympathetic neuronal response, had no training-related changes during LBNP. We conclude that exercise-trained females have a high incidence of orthostatic intolerance during LBNP, with a greater reduction of SV independent of changes in baroreflex and neurohumoral function. A lower incidence of LBNP intolerance in UT may be accounted for by a lower reduction of SV during LBNP. An increase in leg compliance in the exercise-trained females may play an important role in inducing pronounced reduction of SV and hence the intolerance to LBNP.

Ratings of Perceived Exertion During Acute Resistance Exercise Performed at Imposed and Self-Selected Loads in Recreationally Trained Women.

PubMed

Cotter, Joshua A; Garver, Matthew J; Dinyer, Taylor K; Fairman, Ciaran M; Focht, Brian C

2017-08-01

Cotter, JA, Garver, MJ, Dinyer, TK, Fairman, CM, and Focht, BC. Ratings of perceived exertion during acute resistance exercise performed at imposed and self-selected loads in recreationally trained women. J Strength Cond Res 31(8): 2313-2318, 2017-Resistance exercise (RE) is commonly used to elicit skeletal muscle adaptation. Relative intensity of a training load links closely with the outcomes of regular RE. This study examined the rating of perceived exertion (RPE) responses to acute bouts of RE using imposed (40% and 70% of 1 repetition maximum [1RM]) and self-selected (SS) loads in recreationally trained women. Twenty physically active women (23.15 ± 2.92 years), who reported regular RE training of at least 3 weekly sessions for the past year, volunteered to participate. During the initial visit, participants completed 1RM testing on 4 exercises in the following order: leg extension, chest press, leg curl, and lat pull-down. On subsequent visits, the same exercises were completed at the SS or imposed loads. The RPE was assessed after the completion of each set of exercises during the 3 RE conditions using the Borg-15 category scale. Self-selected loads corresponded to an average of approximately 57%1RM (±7.62). Overall, RPE increased with load (40%1RM = 11.26 [±1.95]; SS 57%1RM = 13.94 [±1.58]; and, 70%1RM = 15.52 [±2.05]). Reflecting the linear pattern found between load and perceived effort, the present data provide evidence that RPE levels less than 15 likely equate to loads which are not consistent with contemporary American College of Sports Medicine (ACSM) guidelines for enhancing musculoskeletal health which includes strength and hypertrophy. Women desiring increases in strength and lean mass likely need to train at an exertion level at or surpassing a rating of 15 on the Borg-15 category. This article examined the modification of training load on perceived exertion, but other variables, such as the number of repetitions completed, may also be targeted to achieve a desired RPE. The primary understanding is that women who engage in RE may not self-select loads that are consistent with the ACSM recommendations for musculoskeletal health.

Effect of static and dynamic exercise on heart rate and blood pressure variabilities.

PubMed

González-Camarena, R; Carrasco-Sosa, S; Román-Ramos, R; Gaitán-González, M J; Medina-Bañuelos, V; Azpiroz-Leehan, J

2000-10-01

This study examines the effect of static and dynamic leg exercises on heart rate variability (HRV) and blood pressure variability (BPV) in humans. 10 healthy male subjects were studied at rest, during static exercise performed at 30% of maximal voluntary contraction (SX30), and during dynamic cycling exercises done at 30% of VO2max (DX30) and at 60% of VO2max (DX60). Respiration, heart rate, and blood pressure signals were digitized to analyze temporal and spectral parameters involving short and overall indexes (SD, deltaRANGE, RMSSD, Total power), power of the low (LF), middle (MF), and high (HF) frequency components, and the baroreceptor sensitivity by the alphaMF index. During SX30, indexes of HRV as SD, deltaRANGE, Total power, and MF in absolute units increased in relation with rest values and were significantly higher (P < 0.001) than during DX30 and DX60; HF during SX30, in normalized and absolute units, was not different of the rest condition but was higher (P < 0.001) than HF during DX30 and DX60. Parameters of BPV as SD and deltaRANGE increased (P < 0.001) during both type of exercises, and significant (P < 0.01) increments were observed on MF during SX30 and DX30; systolic HF was attenuated during DX30 (P < 0.05), whereas diastolic HF was augmented during DX60 (P < 0.001). Compared with rest condition, the alphaMF index decreased (P < 0.01) only during dynamic exercises. Because HRV and BPV response is different when induced by static or dynamic exercise, differences in the autonomic activity can be advised. Instead of the vagal withdrawal and sympathetic augmentation observed during dynamic exercise, the increase in the overall HRV and the MF component during static exercise suggest an increased activity of both autonomic branches.

Segmental extracellular and intracellular water distribution and muscle glycogen after 72-h carbohydrate loading using spectroscopic techniques.

PubMed

Shiose, Keisuke; Yamada, Yosuke; Motonaga, Keiko; Sagayama, Hiroyuki; Higaki, Yasuki; Tanaka, Hiroaki; Takahashi, Hideyuki

2016-07-01

Body water content increases during carbohydrate loading because 2.7-4-g water binds each 1 g of glycogen. Bioelectrical impedance spectroscopy (BIS) allows separate assessment of extracellular and intracellular water (ECW and ICW, respectively) in the whole body and each body segment. However, BIS has not been shown to detect changes in body water induced by carbohydrate loading. Here, we aimed to investigate whether BIS had sufficient sensitivity to detect changes in body water content and to determine segmental water distribution after carbohydrate loading. Eight subjects consumed a high-carbohydrate diet containing 12 g carbohydrates·kg body mass(-1)·day(-1) for 72 h after glycogen depletion cycling exercise. Changes in muscle glycogen concentration were measured by (13)C-magnetic resonance spectroscopy, and total body water (TBW) was measured by the deuterium dilution technique (TBWD2O). ICW and ECW in the whole body (wrist-to-ankle) and in each body segment (arm, trunk, and leg) were assessed by BIS. Muscle glycogen concentration [72.7 ± 10.0 (SD) to 169.4 ± 55.9 mmol/kg wet wt, P < 0.001] and TBWD2O (39.3 ± 3.2 to 40.2 ± 3.0 kg, P < 0.05) increased significantly 72 h after exercise compared with baseline, respectively. Whole-body BIS showed significant increases in ICW (P < 0.05), but not in ECW. Segmental BIS showed significant increases in ICW in the legs (P < 0.05), but not in the arms or trunk. Our results suggest that increase in body water after carbohydrate loading can be detected by BIS and is caused by segment-specific increases in ICW. Copyright © 2016 the American Physiological Society.

Men exhibit greater fatigue resistance than women in alternated bench press and leg press exercises.

PubMed

Monteiro, Estêvão R; Steele, James; Novaes, Jefferson S; Brown, Amanda F; Cavanaugh, Mark T; Vingren, Jakob L; Behm, David G

2017-11-17

The purpose of this study was to evaluate the influence of sex, exercise order, and rest interval on neuromuscular fatigue resistance for an alternated strength training sequence of bench press (BP) and leg press (LP) exercises. Twelve women and 16 men, both recreationally trained, performed four sessions in a random order: 1) BP followed by LP with three-minutes rest (BP+LP with rest), 2) LP followed by BP with three-minutes rest (LP+BP with rest), 3) BP followed by LP without rest interval (BP+LP no rest), and 4) LP followed by BP without rest interval (LP+BP no rest). Participants performed four sets with 100% of 10RM load to concentric failure with the goal of completing the maximum number of repetitions in both exercises. The fatigue index was analyzed from the first and last sets of each exercise bout. A main effect for sex showed that women exhibited 25.5% (p=0.001) and 24.5% (p=0.001) greater BP and LP fatigue than men respectively when performing 10RM. Men exhibited greater BP (p<0.0001; 34.1%) and LP (p<0.0001; 30.5%) fatigue resistance when a rest period was provided. Men did not show an exercise order effect for BP fatigue and exhibited greater (p=0.0003; 14.5%) LP fatigue resistance when BP was performed first. The present study demonstrated the greater fatigue resistance of men when performing 10RM BP and LP exercises. Since men tend to experience less fatigue with the second exercise in the exercise pairing, women's training programs should be adjusted to ensure they do not parallel men's resistance training programs.

Effects Of Exercise During Prolonged Bed Rest

NASA Technical Reports Server (NTRS)

Arnaud, S.; Berry, P; Cohen, M.; Danelis, J.; Deroshia, C.; Greenleaf, J.; Harris, B.; Keil, L.; Bernauer, E.; Bond, M.;

Beef extract supplementation increases leg muscle mass and modifies skeletal muscle fiber types in rats.

PubMed

Yoshihara, Hiroyuki; Wakamatsu, Jun-Ichiro; Kawabata, Fuminori; Mori, Sunao; Haruno, Atsushi; Hayashi, Toshiya; Sekiguchi, Takeshi; Mizunoya, Wataru; Tatsumi, Ryuichi; Ito, Tatsumi; Ikeuchi, Yoshihide

2006-06-01

The objective of this research was to investigate the effects of beef extract on fat metabolism, muscle mass and muscle fiber types in rats. We also investigated the synergetic effect of endurance exercise. Twenty-four male rats weighing about 270 g were assigned to two diets containing 0 or 6% beef extract (BE). Half the rats fed each diet were subjected to compulsory exercise (CE) for 30 min every other day. After 4 weeks feeding, the blood was collected and various organs were dissected. The muscle fiber type of the soleus and extensor digitorum longus (EDL) muscles were evaluated by histochemical and electrophoretical analyses. Rats supplemented with BE showed a decrease in fat content in liver and abdomen and an increase in the activity of carnitine palmitoyl transferase II in liver. BE as well as exercise increased the relative weights of both soleus and EDL. BE alone and BE plus CE did not affect the distribution of muscle fiber types in soleus. BE without exercise decreased in type IIb of EDL from 54% to 44% with compensatory increase in type IIa from 41% to 49% and type I from 5% to 7% compared with the nonsupplemented, nonexercised control group. No synergetic effect on a fast to slow fiber conversion due to the combination of BE and CE was detected. Thus, BE supplement increased muscle mass and slow type fiber in EDL. The effects of BE supplement on muscle characteristics were similar to those of exercise. beef extract, fat metabolism, muscle fiber type, muscle mass, L-carnitine

Dilated Cardiomyopathy

MedlinePlus

... or lying down Reduced ability to exercise Swelling (edema) in your legs, ankles and feet Swelling of ... making your heart pump less effectively. Fluid buildup (edema). Fluid can build up in the lungs, abdomen, ...

Effect of timing of protein and carbohydrate intake after resistance exercise on nitrogen balance in trained and untrained young men.

PubMed

Mori, Hiroyasu

2014-08-06

Resistance exercise alters the post-exercise response of anabolic and catabolic hormones. A previous study indicated that the turnover of muscle protein in trained individuals is reduced due to alterations in endocrine factors caused by resistance training, and that muscle protein accumulation varies between trained and untrained individuals due to differences in the timing of protein and carbohydrate intake. We investigated the effect of the timing of protein and carbohydrate intake after resistance exercise on nitrogen balance in trained and untrained young men. Subjects were 10 trained healthy men (mean age, 23 ± 4 years; height, 173.8 ± 3.1 cm; weight, 72.3 ± 4.3 kg) and 10 untrained healthy men (mean age, 23 ± 1 years; height, 171.8 ± 5.0 cm; weight, 64.5 ± 5.0 kg). All subjects performed four sets of 8 to 10 repetitions of a resistance exercise (comprising bench press, shoulder press, triceps pushdown, leg extension, leg press, leg curl, lat pulldown, rowing, and biceps curl) at 80% one-repetition maximum. After each resistance exercise session, subjects were randomly divided into two groups with respect to intake of protein (0.3 g/kg body weight) and carbohydrate (0.8 g/kg body weight) immediately after (P0) or 6 h (P6) after the session. All subjects were on an experimental diet that met their individual total energy requirement. We assessed whole-body protein metabolism by measuring nitrogen balance at P0 and P6 on the last 3 days of exercise training. The nitrogen balance was significantly lower in the trained men than in the untrained men at both P0 (P <0.05) and P6 (P <0.01). The nitrogen balance in trained men was significantly higher at P0 than at P6 (P <0.01), whereas that in the untrained men was not significantly different between the two periods. The timing of protein and carbohydrate intake after resistance exercise influences nitrogen balance differently in trained and untrained young men.

Effect of timing of protein and carbohydrate intake after resistance exercise on nitrogen balance in trained and untrained young men

PubMed Central

2014-01-01

Background Resistance exercise alters the post-exercise response of anabolic and catabolic hormones. A previous study indicated that the turnover of muscle protein in trained individuals is reduced due to alterations in endocrine factors caused by resistance training, and that muscle protein accumulation varies between trained and untrained individuals due to differences in the timing of protein and carbohydrate intake. We investigated the effect of the timing of protein and carbohydrate intake after resistance exercise on nitrogen balance in trained and untrained young men. Methods Subjects were 10 trained healthy men (mean age, 23 ± 4 years; height, 173.8 ± 3.1 cm; weight, 72.3 ± 4.3 kg) and 10 untrained healthy men (mean age, 23 ± 1 years; height, 171.8 ± 5.0 cm; weight, 64.5 ± 5.0 kg). All subjects performed four sets of 8 to 10 repetitions of a resistance exercise (comprising bench press, shoulder press, triceps pushdown, leg extension, leg press, leg curl, lat pulldown, rowing, and biceps curl) at 80% one-repetition maximum. After each resistance exercise session, subjects were randomly divided into two groups with respect to intake of protein (0.3 g/kg body weight) and carbohydrate (0.8 g/kg body weight) immediately after (P0) or 6 h (P6) after the session. All subjects were on an experimental diet that met their individual total energy requirement. We assessed whole-body protein metabolism by measuring nitrogen balance at P0 and P6 on the last 3 days of exercise training. Results The nitrogen balance was significantly lower in the trained men than in the untrained men at both P0 (P <0.05) and P6 (P <0.01). The nitrogen balance in trained men was significantly higher at P0 than at P6 (P <0.01), whereas that in the untrained men was not significantly different between the two periods. Conclusion The timing of protein and carbohydrate intake after resistance exercise influences nitrogen balance differently in trained and untrained young men. PMID:25096224

Exercise increases pressure pain tolerance but not pressure and heat pain thresholds in healthy young men.

PubMed

Vaegter, H B; Hoeger Bement, M; Madsen, A B; Fridriksson, J; Dasa, M; Graven-Nielsen, T

2017-01-01

Exercise causes an acute decrease in the pain sensitivity known as exercise-induced hypoalgesia (EIH), but the specificity to certain pain modalities remains unknown. This study aimed to compare the effect of isometric exercise on the heat and pressure pain sensitivity. On three different days, 20 healthy young men performed two submaximal isometric knee extensions (30% maximal voluntary contraction in 3 min) and a control condition (quiet rest). Before and immediately after exercise and rest, the sensitivity to heat pain and pressure pain was assessed in randomized and counterbalanced order. Cuff pressure pain threshold (cPPT) and pain tolerance (cPTT) were assessed on the ipsilateral lower leg by computer-controlled cuff algometry. Heat pain threshold (HPT) was recorded on the ipsilateral foot by a computer-controlled thermal stimulator. Cuff pressure pain tolerance was significantly increased after exercise compared with baseline and rest (p < 0.05). Compared with rest, cPPT and HPT were not significantly increased by exercise. No significant correlation between exercise-induced changes in HPT and cPPT was found. Test-retest reliability before and after the rest condition was better for cPPT and CPTT (intraclass correlation > 0.77) compared with HPT (intraclass correlation = 0.54). The results indicate that hypoalgesia after submaximal isometric exercise is primarily affecting tolerance of pressure pain compared with the pain threshold. These data contribute to the understanding of how isometric exercise influences pain perception, which is necessary to optimize the clinical utility of exercise in management of chronic pain. The effect of isometric exercise on pain tolerance may be relevant for patients in chronic musculoskeletal pain as a pain-coping strategy. WHAT DOES THIS STUDY ADD?: The results indicate that hypoalgesia after submaximal isometric exercise is primarily affecting tolerance of pressure pain compared with the heat and pressure pain threshold. These data contribute to the understanding of how isometric exercise influences pain perception, which is necessary to optimize the clinical utility of exercise in management of chronic pain. © 2016 European Pain Federation - EFIC®.

Effects of egg white protein supplementation on muscle strength and serum free amino acid concentrations.

PubMed

Hida, Azumi; Hasegawa, Yuko; Mekata, Yuko; Usuda, Mika; Masuda, Yasunobu; Kawano, Hitoshi; Kawano, Yukari

2012-10-19

The aim of this study was to evaluate the effects of egg white protein compared to carbohydrate intake prior to exercise on fat free mass (FFM), one repetition maximum (1RM) muscle strength and blood biochemistry in female athletes. Thirty healthy female collegiate athletes were recruited for this study and matched by sport type, body fat percentage and 1RM leg curl muscle strength. Participants were randomly divided into two groups: protein group (15.0 g egg white protein; 75 kcal) and carbohydrate group (17.5 g maltodextrin, 78 kcal). Supplements were administered daily at the same time in a double-blind manner prior to training during an 8-week period. Measurements were performed before and after the 8-week regimen. The mean dietary energy intake did not change throughout the study period. FFM and 1RM assessments (i.e., leg curl, leg extension, squat, and bench press) increased in both groups. Furthermore, serum urea and serum citrulline levels after the 8-week regimen increased significantly only in the protein group. Our findings indicated that compared to the carbohydrate supplement, the protein supplement was associated with some changes in protein metabolites but not with changes in body composition or muscle strength.

Effects of Egg White Protein Supplementation on Muscle Strength and Serum Free Amino Acid Concentrations

PubMed Central

Hida, Azumi; Hasegawa, Yuko; Mekata, Yuko; Usuda, Mika; Masuda, Yasunobu; Kawano, Hitoshi; Kawano, Yukari

2012-01-01

The aim of this study was to evaluate the effects of egg white protein compared to carbohydrate intake prior to exercise on fat free mass (FFM), one repetition maximum (1RM) muscle strength and blood biochemistry in female athletes. Thirty healthy female collegiate athletes were recruited for this study and matched by sport type, body fat percentage and 1RM leg curl muscle strength. Participants were randomly divided into two groups: protein group (15.0 g egg white protein; 75 kcal) and carbohydrate group (17.5 g maltodextrin, 78 kcal). Supplements were administered daily at the same time in a double-blind manner prior to training during an 8-week period. Measurements were performed before and after the 8-week regimen. The mean dietary energy intake did not change throughout the study period. FFM and 1RM assessments (i.e., leg curl, leg extension, squat, and bench press) increased in both groups. Furthermore, serum urea and serum citrulline levels after the 8-week regimen increased significantly only in the protein group. Our findings indicated that compared to the carbohydrate supplement, the protein supplement was associated with some changes in protein metabolites but not with changes in body composition or muscle strength. PMID:23201768

[Basic mechanisms of QRS voltage changes on ECG of healthy subjects during the exercise test].

PubMed

Saltykova, M M

2015-01-01

Electrocardiography is the most commonly used technique for detection stress-induced myocardial ischemia. However, the sensitivity of ECG-criteria is not high. One of the major problem is the difficulty in differentiating ECG changes caused by various factors. The aim of this study was to evaluate the dependence of the QRS voltage changes during exercise on parameters of central hemodynamics, gender particularities and to reveal mechanisms causing these changes. To eliminate the effect of changes in cardiomyocytes transmembrane potentials under the influence of the neurotransmitters of the autonomic nervous system during stepwise increasing exercises and/or due to a lack of ATP results from inadequate myocardial blood flow only healthy subjects not older than 35 years were included in the study (7 men and 7 women) and only periods of ventricular depolarization (QRS complex on the ECG) were included in the analysis. We compared the changes of QRS waves during exercise sessions with two upper and one lower limbs in both men and women. The exercise load was twice bigger in exercise with one leg relative to exercise with two arms. Responses of heart rate and systolic arterial pressure were similar. Amplitude of S-wave in left chest leads significantly increased in both sessions without significant difference between augmentations in the sessions and in groups of men and women. Significant relationship between the S wave augmentation and the peak systolic arterial pressure were revealed. Furthermore, the QRS changes during the exercise with vertical and a horizontal torso position were compared to assess the impact of diastolic arterial pressure and displacement of the diaphragm and heart rotation due to increase of abdominal pressure during the last steps of exercise. The obtained results allow us to exclude the impact of the heart position and size changes, as well as the exercise load on S-wave changes and make a conclusion about the dependence of this parameter on the value of systolic blood pressure.

Acute Effects of Different Stretching Techniques on the Number of Repetitions in A Single Lower Body Resistance Training Session

PubMed Central

Sá, Marcos A.; Neto, Gabriel R.; Costa, Pablo B.; Gomes, Thiago M.; Bentes, Cláudio M.; Brown, Amanda F.; Novaes, Jefferson S.

2015-01-01

This study aimed to investigate the acute effects of passive static and ballistic stretching on maximal repetition performance during a resistance training session (RTS). Nine male subjects underwent three experimental conditions: ballistic stretching (BS); passive static stretching (PSS); and a specific warm-up (SW). The RTS was composed of three sets of 12RM for the following exercises: leg press 45 (LP), leg extension (LE), leg curl (LC), and plantar flexors (PF). Performance of six sessions was assessed 48 hours apart. The first visit consisted of a familiarization session including stretching methods and exercises used in the RTS. On the second and third visit, a strength test and retest were performed. During the fourth to the sixth visit, the volunteers randomly performed the following protocols: BS+RTS; PSS+RTS; or SW+RTS. For the sum of the RM number of each three-set exercise, significant differences were found between PSS vs. SW for the LP (p = 0.001); LE (p = 0.005); MF (p = 0.001); and PF (p = 0.038). For the comparison between the methods of stretching PSS vs. BS, significant differences were found only for the FP (p = 0.019). When analyzing the method of stretching BS vs. SW, significant differences were found for the LP (p = 0.014) and MF (p = 0.002). For the total sum of the RM number of three sets of the four exercises that composed the RTS, significant differences were observed (p < 0.05) in the following comparisons: PPS vs. SW (p = 0.001), PPS vs. BS (p = 0.008), and BS vs. SW (p = 0.002). Accordingly, the methods of passive static and ballistic stretching should not be recommended before a RTS. PMID:25964821

Eccentric-Overload Training in Team-Sport Functional Performance: Constant Bilateral Vertical Versus Variable Unilateral Multidirectional Movements.

PubMed

Gonzalo-Skok, Oliver; Tous-Fajardo, Julio; Valero-Campo, Carlos; Berzosa, César; Bataller, Ana Vanessa; Arjol-Serrano, José Luis; Moras, Gerard; Mendez-Villanueva, Alberto

2017-08-01

To analyze the effects of 2 different eccentric-overload training (EOT) programs, using a rotational conical pulley, on functional performance in team-sport players. A traditional movement paradigm (ie, squat) including several sets of 1 bilateral and vertical movement was compared with a novel paradigm including a different exercise in each set of unilateral and multi-directional movements. Forty-eight amateur or semiprofessional team-sport players were randomly assigned to an EOT program including either the same bilateral vertical (CBV, n = 24) movement (squat) or different unilateral multidirectional (VUMD, n = 24) movements. Training programs consisted of 6 sets of 1 exercise (CBV) or 1 set of 6 exercises (VUMD) × 6-10 repetitions with 3 min of passive recovery between sets and exercises, biweekly for 8 wk. Functional-performance assessment included several change-of-direction (COD) tests, a 25-m linear-sprint test, unilateral multidirectional jumping tests (ie, lateral, horizontal, and vertical), and a bilateral vertical-jump test. Within-group analysis showed substantial improvements in all tests in both groups, with VUMD showing more robust adaptations in pooled COD tests and lateral/horizontal jumping, whereas the opposite occurred in CBV respecting linear sprinting and vertical jumping. Between-groups analyses showed substantially better results in lateral jumps (ES = 0.21), left-leg horizontal jump (ES = 0.35), and 10-m COD with right leg (ES = 0.42) in VUMD than in CBV. In contrast, left-leg countermovement jump (ES = 0.26) was possibly better in CBV than in VUMD. Eight weeks of EOT induced substantial improvements in functional-performance tests, although the force-vector application may play a key role to develop different and specific functional adaptations.

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

Ventilatory responses to dynamic exercise elicited by intramuscular sensors

NASA Technical Reports Server (NTRS)

Smith, S. A.; Gallagher, K. M.; Norton, K. H.; Querry, R. G.; Welch-O'Connor, R. M.; Raven, P. B.

1999-01-01

PURPOSE: Eight subjects, aged 27.0+/-1.6 yr, performed incremental workload cycling to investigate the contribution of skeletal muscle mechano- and metaboreceptors to ventilatory control during dynamic exercise. METHODS: Each subject performed four bouts of exercise: exercise with no intervention (CON); exercise with bilateral thigh cuffs inflated to 90 mm Hg (CUFF); exercise with application of lower-body positive pressure (LBPP) to 45 torr (PP); and exercise with 90 mm Hg thigh cuff inflation and 45 torr LBPP (CUFF+PP). Ventilatory responses and pulmonary gas exchange variables were collected breath-by-breath with concomitant measurement of leg intramuscular pressure. RESULTS: Ventilation (VE) was significantly elevated from CON during PP and CUFF+PP at workloads corresponding to > or = 60% CON peak oxygen uptake (VO2peak) and during CUFF at workloads > or = 80% CON VO2peak, P < 0.05. The VO2 at which ventilatory threshold occurred was significantly reduced from CON (2.17+/-0.28 L x min(-1)) to 1.60+/-0.19 L x min(-1), 1.45+/-0.15 L x min(-1), and 1.15+/-0.11 L x min(-1) during CUFF, PP, and CUFF+PP, respectively. The slope of the linear regression describing the VE/CO2 output relationship was increased from CON by approximately 22% during CUFF, 40% during PP, and 41% during CUFF+PP. CONCLUSIONS: As intramuscular pressure was significantly elevated immediately upon application of LBPP during PP and CUFF+PP without a concomitant increase in VE, it seems unlikely that LBPP-induced increases in VE can be attributed to activation of the mechanoreflex. These findings suggest that LBPP-induced reductions in perfusion pressure and decreases in venous outflow resulting from inflation of bilateral thigh cuffs may generate a metabolite sensitive intramuscular ventilatory stimulus.

Exercise does not produce hypoalgesia when performed immediately after a painful stimulus.

PubMed

Gajsar, Hannah; Nahrwold, Katharina; Titze, Christina; Hasenbring, Monika I; Vaegter, Henrik B

2018-04-25

Exercise-induced hypoalgesia (EIH) and conditioned pain modulation (CPM) are assumed to reflect descending pain inhibition. Potential interactions between EIH and CPM may be important in the therapy of chronic pain, as reduced CPM and increased pain after exercise are frequently observed. This study compared the EIH response after CPM was activated using a cold pressor task with the EIH response after a control condition. Thirty-one participants (age: 27.7±9.8; 15 female) completed two sessions: a cold pressor task (CPT) session, i.e. testing EIH with preceding CPM activation induced using a 2 min CPT at approximately 2°C, and a control session, i.e. testing EIH after a control condition (2 min of quiet rest). EIH was induced using a 15 min bicycling exercise at a target heart rate corresponding to 75% VO2 max. Repeated measures ANOVAs on pressure pain thresholds (PPTs) at the hand, back and leg were used to determine the effects of exercise after the cold pressor test and control condition. Furthermore, correlations between CPM and EIH, in the CPT session as well as control session, were calculated at each assessment site. A significant time x condition interaction (F(1, 30)=43.61, p<0.001, partial η2=0.59), with Bonferroni-corrected post-hoc t-tests showed that PPTs increased after exercise in the control session (p<0.001), but not in the CPT session (p=0.125). Furthermore, there was a small positive correlation of EIH in the control session and CPM at the hand (r=0.37, p=0.043). There was a moderate negative correlation of EIH in the CPT session and CPM at the hand (r=-0.50, p=0.004), and smaller negative correlations at the back (r=-0.37, p=0.036) and at the leg (r=-0.35, p=0.054). Attenuated EIH after the CPM activation in comparison to a control condition suggests that EIH and CPM may share underlying pain inhibitory mechanisms on a systemic level. This assumption is further supported by the finding of small to moderate significant correlations between EIH and CPM at the hand. The attenuated EIH response furthermore suggests that these mechanisms are exhaustible, i.e. that its effects decline after a certain amount of inhibition. In patients with chronic pain, assessing the current capacity of the descending pain inhibitory system - as indicated by the CPM response - may aid to make better predictions about how patients will respond to exercise with respect to acute pain reduction.

Panax ginseng and Salvia miltiorrhiza supplementation during eccentric resistance training in middle-aged and older adults: A double-blind randomized control trial.

PubMed

Lin, Hsin-Fu; Chou, Chun-Chung; Chao, Hsiao-Han; Tanaka, Hirofumi

2016-12-01

Muscle damage induced by an acute bout of eccentric exercise results in transient arterial stiffening. In this study, we sought to determine the effects of progressive eccentric resistance exercise training on vascular functions, and whether herb supplementation would enhance training adaptation by ameliorating the arterial stiffening effects. By using a double-blinded randomized placebo-controlled design, older adults were randomly assigned to either the Panax ginseng and Salvia miltiorrhiza supplementation group (N=12) or the placebo group (N=11). After pre-training testing, all subjects underwent 12 weeks of unilateral eccentric-only exercise training on knee extensor. Maximal leg strength and muscle quality increased in both groups (P<0.05). Relative increases in muscle mass were significantly greater in the placebo group than in the herb supplement group. Eccentric exercise training did not elicit any significant changes in muscle damage, oxidative and inflammatory biomarkers. There were no significant changes in blood pressure or endothelium-dependent vasodilation. None of the measures of arterial stiffness changed significantly with eccentric resistance training in both groups. These results suggest that Chinese herb supplementation does not appear to modulate vascular, and inflammatory adaptations to eccentric exercise training in middle-aged and older adults. However, Chinese herb supplementation abolished the increase in muscle mass induced by eccentric resistance training. (Trial registration: ClinicalTrials.gov: NCT02007304. Registered Dec. 5, 2013). Copyright © 2016 Elsevier Ltd. All rights reserved.

Continuous Positive Airway Pressure During Exercise Improves Walking Time in Patients Undergoing Inpatient Cardiac Rehabilitation After Coronary Artery Bypass Graft Surgery: A RANDOMIZED CONTROLLED TRIAL.

PubMed

Pantoni, Camila Bianca Falasco; Di Thommazo-Luporini, Luciana; Mendes, Renata Gonçalves; Caruso, Flávia Cristina Rossi; Mezzalira, Daniel; Arena, Ross; Amaral-Neto, Othon; Catai, Aparecida Maria; Borghi-Silva, Audrey

2016-01-01

Continuous positive airway pressure (CPAP) has been used as an effective support to decrease the negative pulmonary effects of coronary artery bypass graft (CABG) surgery. However, it is unknown whether CPAP can positively influence patients undergoing CABG during exercise. This study evaluated the effectiveness of CPAP on the first day of ambulation after CABG in patients undergoing inpatient cardiac rehabilitation (CR). Fifty-four patients after CABG surgery were randomly assigned to receive either inpatient CR and CPAP (CPG) or standard CR without CPAP (CG). Cardiac rehabilitation included walking and CPAP pressures were set between 10 to 12 cmH2O. Participants were assessed on the first day of walking at rest and during walking. Outcome measures included breathing pattern variables, exercise time in seconds (ETs), dyspnea/leg effort ratings, and peripheral oxygen saturation (SpO2). Twenty-seven patients (13 CPG vs 14 CG) completed the study. Compared with walking without noninvasive ventilation assistance, CPAP increased ETs by 43.4 seconds (P = .040) during walking, promoted better thoracoabdominal coordination, increased ventilation during walking by 12.5 L/min (P = .001), increased SpO2 values at the end of walking by 2.6% (P = .016), and reduced dyspnea ratings by 1 point (P = .008). Continuous positive airway pressure can positively influence exercise tolerance, ventilatory function, and breathing pattern in response to a single bout of exercise after CABG.

Reliability of laser Doppler, near-infrared spectroscopy and Doppler ultrasound for peripheral blood flow measurements during and after exercise in the heat.

PubMed

Choo, Hui C; Nosaka, Kazunori; Peiffer, Jeremiah J; Ihsan, Mohammed; Yeo, Chow C; Abbiss, Chris R

2017-09-01

This study examined the test-retest reliability of near-infrared spectroscopy (NIRS), laser Doppler flowmetry (LDF) and Doppler ultrasound to assess exercise-induced haemodynamics. Nine men completed two identical trials consisting of 25-min submaximal cycling at first ventilatory threshold followed by repeated 30-s bouts of high-intensity (90% of peak power) cycling in 32.8 ± 0.4°C and 32 ± 5% relative humidity (RH). NIRS (tissue oxygenation index [TOI] and total haemoglobin [tHb]) and LDF (perfusion units [PU]) signals were monitored continuously during exercise, and leg blood flow was assessed by Doppler ultrasound at baseline and after exercise. Cutaneous vascular conductance (CVC; PU/mean arterial pressure (MAP)) was expressed as the percentage change from baseline (%CVC BL ). Coefficients of variation (CVs) as indicators of absolute reliability were 18.7-28.4%, 20.2-33.1%, 42.5-59.8%, 7.8-12.4% and 22.2-30.3% for PU, CVC, %CVC BL , TOI and tHb, respectively. CVs for these variables improved as exercise continued beyond 10 min. CVs for baseline and post-exercise leg blood flow were 17.8% and 10.5%, respectively. CVs for PU, tHb (r 2  = 0.062) and TOI (r 2  = 0.002) were not correlated (P > 0.05). Most variables demonstrated CVs lower than the expected changes (35%) induced by training or heat stress; however, minimum of 10 min exercise is recommended for more reliable measurements.

Functional Fitness Testing Results Following Long-Duration ISS Missions.

PubMed

Laughlin, Mitzi S; Guilliams, Mark E; Nieschwitz, Bruce A; Hoellen, David

2015-12-01

Long-duration spaceflight missions lead to the loss of muscle strength and endurance. Significant reduction in muscle function can be hazardous when returning from spaceflight. To document these losses, NASA developed medical requirements that include measures of functional strength and endurance. Results from this Functional Fitness Test (FFT) battery are also used to evaluate the effectiveness of in-flight exercise countermeasures. The purpose of this paper is to document results from the FFT and correlate this information with performance of in-flight exercise on board the International Space Station. The FFT evaluates muscular strength and endurance, flexibility, and agility and includes the following eight measures: sit and reach, cone agility, push-ups, pull-ups, sliding crunches, bench press, leg press, and hand grip dynamometry. Pre- to postflight functional fitness measurements were analyzed using dependent t-tests and correlation analyses were used to evaluate the relationship between functional fitness measurements and in-flight exercise workouts. Significant differences were noted post space flight with the sit and reach, cone agility, leg press, and hand grip measurements while other test scores were not significantly altered. The relationships between functional fitness and in-flight exercise measurements showed minimal to moderate correlations for most in-flight exercise training variables. The change in FFT results can be partially explained by in-flight exercise performance. Although there are losses documented in the FFT results, it is important to realize that the crewmembers are successfully performing activities of daily living and are considered functional for normal activities upon return to Earth.

Aerobic-synergized exercises may improve fall-related physical fitness in older adults.

PubMed

Chang, Yu-Chen; Wang, Jung-Der; Chen, Ho-Cheng; Hu, Susan C

2017-05-01

The purpose of the present study was to determine whether a synergistic exercise model based on aerobics with additional fall-preventive components could provide extra benefits compared with the same duration of aerobic-synergistic exercise alone. A total of 102 adults aged 65 years and over from three geographically separated communities were assigned to three groups: the general aerobic exercise (GAE) group (N.=44), the GAE plus ball game group (BG group; N.=30) and the GAE plus square-stepping exercise group (SSE group; N.=28). Each group participated in one hour of exercise intervention and two hours of leisure activities twice weekly for 12 weeks. Each exercise session consisted of one hour of combined exercises performed in the following order: 10 minutes of warm-up activities, 20 minutes of aerobics, 20 minutes of the respective exercise model, and 10 minutes of cool-down activities. Functional fitness tests, including aerobic endurance, leg strength, flexibility, reaction time, static balance and mobility, were measured before and after the intervention. Paired t-tests and mixed model analyses were conducted to compare the differences in each measurement within and among the groups. All of the groups exhibited significantly positive effects (P<0.05), including improvements in aerobic endurance, leg muscle strength, static balance, and mobility, after the intervention. There were no significant differences in these improvements in the other two groups compared with group GAE. However, group BG and group SSE showed significantly greater improvements in mobility compared with group GAE (P<0.05). We conclude that a combination of aerobics and selected fall-prevention exercises performed over a consistent period may improve mobility without compromising the fundamental benefits of aerobics. Future studies using randomized control trials with recorded fall events and a longer period of follow-up are indicated to validate the effects of fall prevention exercises.

Effects of an Exercise Programme on Functional Capacity, Body Composition and Risk of Falls in Patients with Cirrhosis: A Randomized Clinical Trial

PubMed Central

Román, Eva; García-Galcerán, Cristina; Torrades, Teresa; Herrera, Silvia; Marín, Ana; Doñate, Maite; Alvarado-Tapias, Edilmar; Malouf, Jorge; Nácher, Laura; Serra-Grima, Ricard; Guarner, Carlos; Soriano, German

2016-01-01

Patients with cirrhosis often have functional limitations, decreased muscle mass, and a high risk of falls. These variables could improve with exercise. The aim was to study the effects of moderate exercise on functional capacity, body composition and risk of falls in patients with cirrhosis. Twenty-three cirrhotic patients were randomized to an exercise programme (n = 14) or to a relaxation programme (n = 9). Both programmes consisted of a one-hour session 3 days a week for 12 weeks. At the beginning and end of the study, we measured functional capacity using the cardiopulmonary exercise test, evaluated body composition using anthropometry and dual energy X-ray absorptiometry, and estimated risk of falls using the Timed Up&Go test. In the exercise group, cardiopulmonary exercise test showed an increase in total effort time (p<0.001) and ventilatory anaerobic threshold time (p = 0.009). Upper thigh circumference increased and mid-arm and mid-thigh skinfold thickness decreased. Dual energy X-ray absorptiometry showed a decrease in fat body mass (-0.94 kg, 95%CI -0.48 to -1.41, p = 0.003) and an increase in lean body mass (1.05 kg, 95%CI 0.27 to 1.82, p = 0.01), lean appendicular mass (0.38 kg, 95%CI 0.06 to 0.69, p = 0.03) and lean leg mass (0.34 kg, 95%CI 0.10 to 0.57, p = 0.02). The Timed Up&Go test decreased at the end of the study compared to baseline (p = 0.02). No changes were observed in the relaxation group. We conclude that a moderate exercise programme in patients with cirrhosis improves functional capacity, increases muscle mass, and decreases body fat and the Timed Up&Go time. Trial Registration: ClinicalTrials.gov NCT01447537 PMID:27011355

Postactivation Potentiation of the Plantar Flexors Does Not Directly Translate to Jump Performance in Female Elite Young Soccer Players.

PubMed

Prieske, Olaf; Maffiuletti, Nicola A; Granacher, Urs

2018-01-01

High-intensity muscle actions have the potential to temporarily improve muscle contractile properties (i.e., postactivation potentiation, PAP) thereby inducing acute performance enhancements. There is evidence that balance training can improve performance during strength exercises. Taking these findings together, the purpose of this study was to examine the acute effects of a combined balance and strength (B+S) exercise vs. a strength only (S) exercise on twitch contractile properties, maximum voluntary strength, and jump performance in young athletes. Female elite young soccer players ( N = 12) aged 14-15 years conducted three experimental conditions in randomized order: S included 3 sets of 8-10 dynamic leg extensions at 80% of the 1-repetition maximum, B+S consisted of 3 sets of 40 s double-leg stances on a balance board prior to leg extensions (same as S), and a resting control period. Before and 7 min after exercise, participants were tested for their electrically-evoked isometric twitches (i.e., twitch peak torque, twitch rate of torque development) and maximal voluntary contraction (MVC) torque of the plantar flexor muscles. Additionally, countermovement (CMJ) and drop jump (DJ) performances (i.e., CMJ/DJ height, DJ ground contact time) were assessed. Significant effects of condition on twitch contractile properties ( p < 0.05, d = 1.1) and jump performance outputs ( p < 0.05, 1.1 ≤ d ≤ 1.2) were found. Post-hoc tests revealed that S compared to control produced larger PAP for twitch peak torques by trend ( p = 0.07, d = 1.8, 33 vs. 21%) and significantly larger PAP for twitch rate of torque development ( p < 0.05, d = 2.4, 55 vs. 43%). Following B+S compared to control, significant improvements in CMJ height ( p < 0.01, d = 1.9, 3%) and DJ contact time were found ( p < 0.01, d = 2.0, 10%). This study revealed protocol-specific acute performance improvements. While S resulted in significant increases in twitch contractile properties, B+S produced significant enhancements in jump performance. It is concluded that PAP effects in the plantar flexors may not directly translate to improved jump performance in female elite young soccer players. Therefore, the observed gains in jump performance following B+S are most likely related to neuromuscular changes (e.g., intramuscular coordination) rather than improved contractile properties.

Postactivation Potentiation of the Plantar Flexors Does Not Directly Translate to Jump Performance in Female Elite Young Soccer Players

PubMed Central

Prieske, Olaf; Maffiuletti, Nicola A.; Granacher, Urs

2018-01-01

High-intensity muscle actions have the potential to temporarily improve muscle contractile properties (i.e., postactivation potentiation, PAP) thereby inducing acute performance enhancements. There is evidence that balance training can improve performance during strength exercises. Taking these findings together, the purpose of this study was to examine the acute effects of a combined balance and strength (B+S) exercise vs. a strength only (S) exercise on twitch contractile properties, maximum voluntary strength, and jump performance in young athletes. Female elite young soccer players (N = 12) aged 14–15 years conducted three experimental conditions in randomized order: S included 3 sets of 8–10 dynamic leg extensions at 80% of the 1-repetition maximum, B+S consisted of 3 sets of 40 s double-leg stances on a balance board prior to leg extensions (same as S), and a resting control period. Before and 7 min after exercise, participants were tested for their electrically-evoked isometric twitches (i.e., twitch peak torque, twitch rate of torque development) and maximal voluntary contraction (MVC) torque of the plantar flexor muscles. Additionally, countermovement (CMJ) and drop jump (DJ) performances (i.e., CMJ/DJ height, DJ ground contact time) were assessed. Significant effects of condition on twitch contractile properties (p < 0.05, d = 1.1) and jump performance outputs (p < 0.05, 1.1 ≤ d ≤ 1.2) were found. Post-hoc tests revealed that S compared to control produced larger PAP for twitch peak torques by trend (p = 0.07, d = 1.8, 33 vs. 21%) and significantly larger PAP for twitch rate of torque development (p < 0.05, d = 2.4, 55 vs. 43%). Following B+S compared to control, significant improvements in CMJ height (p < 0.01, d = 1.9, 3%) and DJ contact time were found (p < 0.01, d = 2.0, 10%). This study revealed protocol-specific acute performance improvements. While S resulted in significant increases in twitch contractile properties, B+S produced significant enhancements in jump performance. It is concluded that PAP effects in the plantar flexors may not directly translate to improved jump performance in female elite young soccer players. Therefore, the observed gains in jump performance following B+S are most likely related to neuromuscular changes (e.g., intramuscular coordination) rather than improved contractile properties. PMID:29628898