The effects of rest interval length on acute bench press performance: the influence of gender and muscle strength.

PubMed

Ratamess, Nicholas A; Chiarello, Christina M; Sacco, Anthony J; Hoffman, Jay R; Faigenbaum, Avery D; Ross, Ryan E; Kang, Jie

2012-07-01

The purpose of this study was to investigate the effects of rest interval (RI) length on bench press performance in subjects with disparity in maximum strength. Two cohorts of subjects performed 3 bench press protocols in random order consisting of 3 sets of up to 10 repetitions with 75% of 1-repetition maximum (1RM) using either 1-, 2-, or 3-minute RIs between sets. In the first cohort, 22 men and women were studied to investigate gender influence. In the second cohort, 23 men were tested for 1RM bench press strength and placed into a low 1RM (mean = 80.7 ± 7.5 kg) or high 1RM (mean = 140.6 ± 11.9 kg) experimental group. The number of successful repetitions completed, average power, and velocity for each set were recorded. Women performed significantly more repetitions than men with 1-minute (26.9 ± 4.4 vs. 21.1 ± 3.5), 2-minute (29.0 ± 2.0 vs. 24.0 ± 4.5), and 3-minute (29.7 ± 1.8 vs. 25.8 ± 5.1) RIs. The magnitude of decline in average velocity and power was significantly higher in men than in women. Total number of repetitions performed was significantly greater in the low 1RM group than in the high 1RM group at 1-minute (21.6 ± 5.0 vs. 18.1 ± 2.0) and 2-minute RIs (24.2 ± 5.4 vs. 21.3 ± 2.8). Significant negative correlations were observed between 1RM bench press and total number of repetitions completed for 1- and 2-minute RIs (r = -0.558 and -0.490, respectively). These data indicate that maximal strength plays a role in bench press performance with varying RIs and suggest that shorter RIs may suffice in women to attain a specific volume.

Development of 1RM Prediction Equations for Bench Press in Moderately Trained Men.

PubMed

Macht, Jordan W; Abel, Mark G; Mullineaux, David R; Yates, James W

2016-10-01

Macht, JW, Abel, MG, Mullineaux, DR, and Yates, JW. Development of 1RM prediction equations for bench press in moderately trained men. J Strength Cond Res 30(10): 2901-2906, 2016-There are a variety of established 1 repetition maximum (1RM) prediction equations, however, very few prediction equations use anthropometric characteristics exclusively or in part, to estimate 1RM strength. Therefore, the purpose of this study was to develop an original 1RM prediction equation for bench press using anthropometric and performance characteristics in moderately trained male subjects. Sixty male subjects (21.2 ± 2.4 years) completed a 1RM bench press and were randomly assigned a load to complete as many repetitions as possible. In addition, body composition, upper-body anthropometric characteristics, and handgrip strength were assessed. Regression analysis was used to develop a performance-based 1RM prediction equation: 1RM = 1.20 repetition weight + 2.19 repetitions to fatigue - 0.56 biacromial width (cm) + 9.6 (R = 0.99, standard error of estimate [SEE] = 3.5 kg). Regression analysis to develop a nonperformance-based 1RM prediction equation yielded: 1RM (kg) = 0.997 cross-sectional area (CSA) (cm) + 0.401 chest circumference (cm) - 0.385%fat - 0.185 arm length (cm) + 36.7 (R = 0.81, SEE = 13.0 kg). The performance prediction equations developed in this study had high validity coefficients, minimal mean bias, and small limits of agreement. The anthropometric equations had moderately high validity coefficient but larger limits of agreement. The practical applications of this study indicate that the inclusion of anthropometric characteristics and performance variables produce a valid prediction equation for 1RM strength. In addition, the CSA of the arm uses a simple nonperformance method of estimating the lifter's 1RM. This information may be used to predict the starting load for a lifter performing a 1RM prediction protocol or a 1RM testing protocol.

Using Bar Velocity to Predict the Maximum Dynamic Strength in the Half-Squat Exercise.

PubMed

Loturco, Irineu; Pereira, Lucas A; Cal Abad, Cesar C; Gil, Saulo; Kitamura, Katia; Kobal, Ronaldo; Nakamura, Fábio Y

2016-07-01

To determine whether athletes from different sport disciplines present similar mean propulsive velocity (MPV) in the half-squat (HS) during submaximal and maximal tests, enabling prediction of 1-repetition maximum (1-RM) from MPV at any given submaximal load. Sixty-four male athletes, comprising American football, rugby, and soccer players; sprinters and jumpers; and combat-sport strikers attended 2 testing sessions separated by 2-4 wk. On the first visit, a standardized 1-RM test was performed. On the second, athletes performed HSs on Smith-machine equipment, using relative percentages of 1-RM to determine the respective MPV of submaximal and maximal loads. Linear regression established the relationship between MPV and percentage of 1-RM. A very strong linear relationship (R2 ≈ .96) was observed between the MPV and the percentages of HS 1-RM, resulting in the following equation: %HS 1-RM = -105.05 × MPV + 131.75. The MPV at HS 1-RM was ~0.3 m/s. This equation can be used to predict HS 1-RM on a Smith machine with a high degree of accuracy.

The effects of two equal-volume training protocols upon strength, body composition and salivary hormones in male rugby union players

PubMed Central

Heke, TOL; Keogh, JWL

2016-01-01

This study examined the effects of two equal-volume resistance-training protocols upon strength, body composition and salivary hormones in male rugby union players. Using a crossover design, 24 male rugby players completed a 4-week full-body (FB) and split-body (SB) training protocol of equal volume during the competitive season. One repetition maximum (1RM) strength, body composition via skinfold measurements and salivary testosterone (T) and cortisol (C) concentrations were assessed pre and post training. The FB and SB protocols improved upper (7.3% and 7.4%) and lower body 1RM strength (7.4% and 5.4%), whilst reducing body fat (-0.9% and -0.4%) and fat mass (-5.7% and -2.1%), respectively (all p ≤ 0.021). The SB protocol elevated T (21%) and C (50%) concentrations with a higher T/C ratio (28%) after FB training (all p ≤ 0.039). The strength changes were similar, but the body composition and hormonal results differed by protocol. Slope testing on the individual responses identified positive associations (p ≤ 0.05) between T and C concentrations and absolute 1RM strength in stronger (squat 1RM = 150.5 kg), but not weaker (squat 1RM = 117.4 kg), men. A short window of training involving FB or SB protocols can improve strength and body composition in rugby players. The similar strength gains highlight training volume as a key adaptive stimulus, although the programme structure (i.e. FB or SB) did influence the body composition and hormonal outcomes. It also appears that 1RM strength is associated with individual hormonal changes and baseline strength. PMID:27274103

The effects of two equal-volume training protocols upon strength, body composition and salivary hormones in male rugby union players.

PubMed

Crewther, B T; Heke, Tol; Keogh, Jwl

2016-06-01

This study examined the effects of two equal-volume resistance-training protocols upon strength, body composition and salivary hormones in male rugby union players. Using a crossover design, 24 male rugby players completed a 4-week full-body (FB) and split-body (SB) training protocol of equal volume during the competitive season. One repetition maximum (1RM) strength, body composition via skinfold measurements and salivary testosterone (T) and cortisol (C) concentrations were assessed pre and post training. The FB and SB protocols improved upper (7.3% and 7.4%) and lower body 1RM strength (7.4% and 5.4%), whilst reducing body fat (-0.9% and -0.4%) and fat mass (-5.7% and -2.1%), respectively (all p ≤ 0.021). The SB protocol elevated T (21%) and C (50%) concentrations with a higher T/C ratio (28%) after FB training (all p ≤ 0.039). The strength changes were similar, but the body composition and hormonal results differed by protocol. Slope testing on the individual responses identified positive associations (p ≤ 0.05) between T and C concentrations and absolute 1RM strength in stronger (squat 1RM = 150.5 kg), but not weaker (squat 1RM = 117.4 kg), men. A short window of training involving FB or SB protocols can improve strength and body composition in rugby players. The similar strength gains highlight training volume as a key adaptive stimulus, although the programme structure (i.e. FB or SB) did influence the body composition and hormonal outcomes. It also appears that 1RM strength is associated with individual hormonal changes and baseline strength.

Efficacy of the National Football League-225 Test to Track Changes in One Repetition Maximum Bench Press After Training in National Collegiate Athletic Association Division IA Football Players.

PubMed

Mann, J Bryan; Ivey, Pat A; Stoner, Josh D; Mayhew, Jerry L; Brechue, William F

2015-11-01

Numerous investigations have attested to the efficacy of the National Football League (NFL)-225 test to estimate one repetition maximum (1RM) bench press. However, no studies have assessed the efficacy of the test to track changes in strength across a training program. The purpose of this study was to determine the accuracy of the NFL-225 test for determining the change in 1RM bench press in National Collegiate Athletic Association Division IA college football players after training. Over a 4-year period, players (n = 203) were assessed before and after a 6-week off-season resistance program for 1RM bench press and repetitions completed with 102.3 kg (225 lbs). Test sessions typically occurred within 1 week of each other. Players significantly increased 1RM by 4.2 ± 8.6 kg and NFL-225 repetitions by 0.9 ± 2.3, although the effect size (ES) for each was trivial (ES = 0.03 and 0.07, respectively). National Football League 225 prediction equations had higher correlations with 1RM before training (intraclass correlation coefficient [ICC] = 0.95) than after training (ICC = 0.75). The correlation between the change in NFL-225 repetitions and change in 1RM was low and negative (r = -0.22, p < 0.02). Short-term heavy resistance training may alter the association between muscular strength and muscular endurance in college football players and render the NFL-225 test less effective in predicting the change in 1RM bench press strength after short-term training.

Upper Extremity Muscle Volumes and Functional Strength After Resistance Training in Older Adults

PubMed Central

Daly, Melissa; Vidt, Meghan E.; Eggebeen, Joel D.; Simpson, W. Greg; Miller, Michael E.; Marsh, Anthony P.; Saul, Katherine R.

2014-01-01

Aging leads to a decline in strength and an associated loss of independence. The authors examined changes in muscle volume, maximum isometric joint moment, functional strength, and 1-repetition maximum (1RM) after resistance training (RT) in the upper extremity of older adults. They evaluated isometric joint moment and muscle volume as predictors of functional strength. Sixteen healthy older adults (average age 75 ± 4.3 yr) were randomized to a 6-wk upper extremity RT program or control group. The RT group increased 1RM significantly (p < .01 for all exercises). Compared with controls, randomization to RT led to greater functional pulling strength (p = .003), isometric shoulder-adduction moment (p = .041), elbow-flexor volume (p = .017), and shoulder-adductor volume (p = .009). Shoulder-muscle volumes and isometric moments were good predictors of functional strength. The authors conclude that shoulder strength is an important factor for performing functional reaching and pulling tasks and a key target for upper extremity RT interventions. PMID:22952203

Predicting maximal strength of quadriceps from submaximal performance in individuals with knee joint osteoarthritis.

PubMed

McNair, Peter J; Colvin, Matt; Reid, Duncan

2011-02-01

To compare the accuracy of 12 maximal strength (1-repetition maximum [1-RM]) equations for predicting quadriceps strength in people with osteoarthritis (OA) of the knee joint. Eighteen subjects with OA of the knee joint attended a rehabilitation gymnasium on 3 occasions: 1) a familiarization session, 2) a session where the 1-RM of the quadriceps was established using a weights machine for an open-chain knee extension exercise and a leg press exercise, and 3) a session where the subjects performed with a load at which they could lift for approximately 10 repetitions only. The data were used in 12 prediction equations to calculate 1-RM strength and compared to the actual 1-RM data. Data were examined using Bland and Altman graphs and statistics, intraclass correlation coefficients (ICCs), and typical error values between the actual 1-RM and the respective 1-RM prediction equation data. Difference scores (predicted 1-RM--actual 1-RM) across the injured and control legs were also compared. For the knee extension exercise, the Brown, Brzycki, Epley, Lander, Mayhew et al, Poliquin, and Wathen prediction equations demonstrated the greatest levels of predictive accuracy. All of the ICCs were high (range 0.96–0.99), and typical errors were between 3% and 4%. For the knee press exercise, the Adams, Berger, Kemmler et al, and O'Conner et al equations demonstrated the greatest levels of predictive accuracy. All of the ICCs were high (range 0.95-0.98), and the typical errors ranged from 5.9-6.3%. This study provided evidence supporting the use of prediction equations to assess maximal strength in individuals with a knee joint with OA.

ACE ID genotype and the muscle strength and size response to unilateral resistance training.

PubMed

Pescatello, Linda S; Kostek, Matthew A; Gordish-Dressman, Heather; Thompson, Paul D; Seip, Richard L; Price, Thomas B; Angelopoulos, Theodore J; Clarkson, Priscilla M; Gordon, Paul M; Moyna, Niall M; Visich, Paul S; Zoeller, Robert F; Devaney, Joseph M; Hoffman, Eric P

2006-06-01

To examine associations among the angiotensin I-converting enzyme (ACE) insertion (I)/deletion (D) polymorphism and the response to a 12-wk (2 d.wk) unilateral, upper-arm resistance training (RT) program in the trained (T, nondominant) and untrained (UT, dominant) arms. Subjects were 631 (mean+/-SEM, 24.2+/-0.2 yr) white (80%) men (42%) and women (58%). The ACE ID genotype was in Hardy-Weinberg equilibrium with frequencies of 23.1, 46.1, and 30.8% for ACE II, ID, and DD, respectively (chi=1.688, P=0.430). Maximum voluntary contraction (MVC) and one-repetition maximum (1RM) assessed peak elbow flexor muscle strength. Magnetic resonance imaging measured biceps muscle cross-sectional area (CSA). Multiple variable and repeated-measures ANCOVA tested whether muscle strength and size differed at baseline and pre- to post-RT among T and UT and ACE ID genotype. Baseline muscle strength and size were greater in UT than T (P<0.001) and did not differ among ACE ID genotype in either arm (P >or= 0.05). In T, MVC increases were greater for ACE II/ID (22%) than DD (17%) (P<0.05), whereas 1RM (51%) and CSA (19%) gains were not different among ACE ID genotype pre- to post-RT (P >or= 0.05). In UT, MVC increased among ACE II/ID (7%) (P<0.001) but was similar among ACE DD (2%) pre- to post-RT (P >or= 0.05). In UT, 1RM (11%) and CSA (2%) increases were greater for ACE DD/ID than ACE II (1RM, 7%; CSA, -0.1%) (P<0.05). ACE ID genotype explained approximately 1% of the MVC response to RT in T and approximately 2% of MVC, 2% of 1RM, and 4% of CSA response in UT (P<0.05). ACE ID genotype is associated with the contralateral effects of unilateral RT, perhaps more so than with the muscle strength and size adaptations that result from RT.

Analysis of factors that influence the maximum number of repetitions in two upper-body resistance exercises: curl biceps and bench press.

PubMed

Iglesias, Eliseo; Boullosa, Daniel A; Dopico, Xurxo; Carballeira, Eduardo

2010-06-01

The purpose of this study was to analyze the influence of exercise type, set configuration, and relative intensity load on relationship between 1 repetition maximum (1RM) and maximum number of repetitions (MNR). Thirteen male subjects, experienced in resistance training, were tested in bench press and biceps curl for 1RM, MNR at 90% of 1RM with cluster set configuration (rest of 30s between repetitions) and MNR at 70% of 1RM with traditional set configuration (no rest between repetitions). A lineal encoder was used for measuring displacement of load. Analysis of variance analysis revealed a significant effect of load (p<0.01) and a tendency in exercise factor (p=0.096), whereas the interaction effect was not significant. MNR at 70% of 1RM was lower for biceps curl (16.31+/-2.59 vs. 8.77+/-3 in bench press and biceps curl, respectively; p<0.05) and at 90% of 1RM (21.85+/-11.06 vs. 18.54+/-12.84 in bench press and biceps curl, respectively; p>0.05). Correlation between 1RM and MNR was significant for medium-intensity in biceps curl (r=-0.574; p<0.05) and between MNR and 1RM/body mass (r=-0.574; p<0.05). Neither 1RM nor 1RM/body mass correlated with velocity along set, so velocity seems to be similar at a same relative intensity for subjects with differences in maximum strength levels. From our results, we suggest the employment of MNR rather than % of 1RM for training monitoring. Furthermore, we suggest the introduction of cluster set configuration for upper-body assessment of MNR and for upper-body muscular endurance training at high-intensity loads, as it seems an efficient approach in looking for sessions with greater training volumes. This could be an interesting approach for such sports as wrestling or weightlifting.

Acute effect of passive static stretching on lower-body strength in moderately trained men.

PubMed

Gergley, Jeffrey C

2013-04-01

The purpose of this investigation was conducted to determine the acute effect of passive static stretching (PSS) of the lower-body musculature on lower-body strength in a 1 repetition maximum (1RM) squat exercise in young (18-24 years.) moderately trained men (n = 17). Two supervised warm-up treatments were applied before each performance testing session using a counterbalanced design on nonconsecutive days. The first treatment consisted of an active dynamic warm-up (AD) with resistance machines (i.e., leg extension/leg flexion) and free weights (i.e., barbell squat), whereas the second treatment added PSS of the lower body plus the AD treatment. One repetition maximum was determined using the maximum barbell squat following a progressive loading protocol. Subjects were also asked to subjectively evaluate their lower-body stability during 1RM testing sessions for both the AD and PSS treatments. A significant decrease in 1RM (8.36%) and lower-body stability (22.68%) was observed after the PSS treatment. Plausible explanations for this observation may be related to a more compliant muscle tendon unit and/or altered or impaired neurologic function in the active musculature. It is also possible that strength was impaired by the PSS because of joint instability. The findings of this study suggest that intensive stretching such as lower-body PSS should be avoided before training the lower body or performing the 1RM in the squat exercise in favor of an AD dynamic warm-up using resistance training equipment in the lower-body musculature.

Maximal strength training improves work economy, rate of force development and maximal strength more than conventional strength training.

PubMed

Heggelund, Jørn; Fimland, Marius S; Helgerud, Jan; Hoff, Jan

2013-06-01

This study compared maximal strength training (MST) with equal training volume (kg × sets × repetitions) of conventional strength training (CON) primarily with regard to work economy, and second one repetition maximum (1RM) and rate of force development (RFD) of single leg knee extension. In an intra-individual design, one leg was randomized to knee-extension MST (4 or 5RM) and the other leg to CON (3 × 10RM) three times per week for 8 weeks. MST was performed with maximal concentric mobilization of force while CON was performed with moderate velocity. Eight untrained or moderately trained men (26 ± 1 years) completed the study. The improvement in gross work economy was -0.10 ± 0.08 L min(-1) larger after MST (P = 0.011, between groups). From pre- to post-test the MST and CON improved net work economy with 31 % (P < 0.001) and 18 % (P = 0.01), respectively. Compared with CON, the improvement in 1RM and dynamic RFD was 13.7 ± 8.4 kg (P = 0.002) and 587 ± 679 N s(-1) (P = 0.044) larger after MST, whereas isometric RFD was of borderline significance 3,028 ± 3,674 N s(-1) (P = 0.053). From pre- to post-test, MST improved 1RM and isometric RFD with 50 % (P < 0.001) and 155 % (P < 0.001), respectively whereas CON improved 1RM and isometric RFD with 35 % (P < 0.001) and 83 % (P = 0.028), respectively. Anthropometric measures of quadriceps femoris muscle mass and peak oxygen uptake did not change. In conclusion, 8 weeks of MST was more effective than CON for improving work economy, 1RM and RFD in untrained and moderately trained men. The advantageous effect of MST to improve work economy could be due to larger improvements in 1RM and RFD.

Maximal power training induced different improvement in throwing velocity and muscle strength according to playing positions in elite male handball players

PubMed Central

Chtourou, H; Souissi, N; Aouidet, A; Chamari, K

2016-01-01

This study was designed to assess the effect of strength and power training on throwing velocity and muscle strength in handball players according to their playing positions. Twenty-two male handball players were assigned to either an experimental group (n=11) or a control group (n=11) (age: 22.1 ± 3.0 years). They were asked to complete (i) the ball throwing velocity test and (ii) the one-repetition maximum (1-RM) tests for the half-back squat, the pull-over, the bench press, the developed neck, and the print exercises before and after 12 weeks of maximal power training. The training was designed to improve strength and power with an intensity of 85-95% of the 1RM. In addition to their usual routine handball training sessions, participants performed two sessions per week. During each session, they performed 3-5 sets of 3-8 repetitions with 3 min of rest in between. Then, they performed specific shots (i.e., 12 to 40). Ball-throwing velocity (p<0.001) was higher after the training period in rear line players (RL). The training programme resulted in an improvement of 1RM bench press (p<0.001), 1RM developed neck (p<0.001) and 1RM print (p<0.001) in both front line (FL) and RL. The control group showed a significant improvement only in ball-throwing velocity (p<0.01) and 1RM bench press (p<0.01) in RL. A significantly greater improvement was found in ball-throwing velocity (p<0.001), 1RM bench press (p<0.001), and 1RM half-back squat exercises in players of the central axis (CA) compared to the lateral axis (LA) (p<0.01). The power training programme induced significantly greater increases in ball-throwing velocity and muscle strength in FL than RL and in CA than LA axis players. PMID:28090144

Maximal power training induced different improvement in throwing velocity and muscle strength according to playing positions in elite male handball players.

PubMed

Cherif, M; Chtourou, H; Souissi, N; Aouidet, A; Chamari, K

2016-12-01

This study was designed to assess the effect of strength and power training on throwing velocity and muscle strength in handball players according to their playing positions. Twenty-two male handball players were assigned to either an experimental group (n=11) or a control group (n=11) (age: 22.1 ± 3.0 years). They were asked to complete (i) the ball throwing velocity test and (ii) the one-repetition maximum (1-RM) tests for the half-back squat, the pull-over, the bench press, the developed neck, and the print exercises before and after 12 weeks of maximal power training. The training was designed to improve strength and power with an intensity of 85-95% of the 1RM. In addition to their usual routine handball training sessions, participants performed two sessions per week. During each session, they performed 3-5 sets of 3-8 repetitions with 3 min of rest in between. Then, they performed specific shots (i.e., 12 to 40). Ball-throwing velocity (p<0.001) was higher after the training period in rear line players (RL). The training programme resulted in an improvement of 1RM bench press (p<0.001), 1RM developed neck (p<0.001) and 1RM print (p<0.001) in both front line (FL) and RL. The control group showed a significant improvement only in ball-throwing velocity (p<0.01) and 1RM bench press (p<0.01) in RL. A significantly greater improvement was found in ball-throwing velocity (p<0.001), 1RM bench press (p<0.001), and 1RM half-back squat exercises in players of the central axis (CA) compared to the lateral axis (LA) (p<0.01). The power training programme induced significantly greater increases in ball-throwing velocity and muscle strength in FL than RL and in CA than LA axis players.

The individual and combined influence of ACE and ACTN3 genotypes on muscle phenotypes before and after strength training.

PubMed

Erskine, R M; Williams, A G; Jones, D A; Stewart, C E; Degens, H

2014-08-01

Alternative measures of muscle size, strength, and power to those used in previous studies could help resolve the controversy surrounding associations between polymorphisms of the angiotensin-I converting enzyme (ACE) and α-actinin-3 (ACTN3) genes and skeletal muscle phenotypes, and the responses to resistance training (RT). To this end, we measured quadriceps femoris muscle volume (Vm), physiological cross-sectional area (PCSA), maximum isometric force (Ft), specific force (Ft per unit PCSA), maximum isoinertial strength (1-RM), and maximum power (Wmax ; n = 40) before and after 9-week knee extension RT in 51 previously untrained young men, who were genotyped for the ACE I/D and ACTN3 R577X polymorphisms. ACTN3 R-allele carriers had greater Vm, 1-RM, and Wmax than XX homozygotes at baseline (all P < 0.05), but responses to RT were independent of ACTN3 genotype (all P > 0.05). Muscle phenotypes were independent of ACE genotype before (all P > 0.05) and after RT (all P > 0.01). However, people with the "optimal" ACE+ACTN3 genotype combination had greater baseline 1-RM and Wmax compared to those with the "suboptimal" profile (both P < 0.0125). We show for the first time that the ACTN3 R577X polymorphism is associated with human Vm and (independently and in combination with the ACE I/D polymorphism) influences 1-RM and Wmax. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Relationship Between Selected Strength and Power Assessments to Peak and Average Velocity of the Drive Block in Offensive Line Play.

PubMed

Jacobson, Bert H; Conchola, Eric C; Smith, Doug B; Akehi, Kazuma; Glass, Rob G

2016-08-01

Jacobson, BH, Conchola, EC, Smith, DB, Akehi, K, and Glass, RG. Relationship between selected strength and power assessments to peak and average velocity of the drive block in offensive line play. J Strength Cond Res 30(8): 2202-2205, 2016-Typical strength training for football includes the squat and power clean (PC) and routinely measured variables include 1 repetition maximum (1RM) squat and 1RM PC along with the vertical jump (VJ) for power. However, little research exists regarding the association between the strength exercises and velocity of an actual on-the-field performance. The purpose of this study was to investigate the relationship of peak velocity (PV) and average velocity (AV) of the offensive line drive block to 1RM squat, 1RM PC, the VJ, body mass (BM), and body composition. One repetition maximum assessments for the squat and PC were recorded along with VJ height, BM, and percent body fat. These data were correlated with PV and AV while performing the drive block. Peal velocity and AV were assessed using a Tendo Power and Speed Analyzer as the linemen fired, from a 3-point stance into a stationary blocking dummy. Pearson product analysis yielded significant (p ≤ 0.05) correlations between PV and AV and the VJ, the squat, and the PC. A significant inverse association was found for both PV and AV and body fat. These data help to confirm that the typical exercises recommended for American football linemen is positively associated with both PV and AV needed for the drive block effectiveness. It is recommended that these exercises remain the focus of a weight room protocol and that ancillary exercises be built around these exercises. Additionally, efforts to reduce body fat are recommended.

Supramaximal Eccentrics Versus Traditional Loading in Improving Lower-Body 1RM: A Meta-Analysis.

PubMed

Buskard, Andrew N L; Gregg, Heath R; Ahn, Soyeon

2018-06-11

Guidelines for improving maximal concentric strength through resistance training (RT) have traditionally included large muscle-group exercises, full ranges of motion, and a load approximating 85% of the 1-repetition maximum (1RM). Supramaximal eccentric training (SME; controlled lowering of loads above the concentric 1RM) has also been shown to be effective at increasing concentric 1RM in the lower body, but concerns regarding injury risk, postexercise soreness, and null benefit over traditional methods (TRAD) may limit the practical utility of this approach. The purpose of this study was to determine whether SME elicits greater lower-body strength improvements than TRAD. Key inclusion criteria were regular exercise modalities typical of nonspecialized exercise facilities (e.g., leg press; key exclusion: isokinetic dynamometer) and at least 6 weeks of RT exposure, leading to 5 studies included in the current meta-analysis. Unbiased effect-size measures that quantify the mean difference in lower-body 1RM between SME and TRAD were extracted. Supramaximal eccentric training did not appear to be more effective than TRAD at increasing lower-body 1RM ([Formula: see text] = .33, SE = .26, z = 1.26, 95% CI [-0.20, 0.79], p = .20, I 2  = 56.78%) under a random-effects model where between-study variance was estimated using maximum likelihood estimation ([Formula: see text] 2 = .25). The selection of SME over TRAD in RT programs designed to increase lower-body 1RM does not appear warranted in all populations. Further research should clarify the merit of periodic SME in TRAD-dominant RT programs as well as whether a differential effect exists in trained individuals.

Strength and power determinants of grinding performance in America's Cup sailors.

PubMed

Pearson, Simon N; Hume, Patria A; Cronin, John B; Slyfield, David

2009-09-01

The purpose grinding is a physically demanding component of America's Cup sailing that is important to overall team performance, but little research is available on the determinants of grinding performance. We examined the relationship between various measures of muscular performance and the performance of upper-body grinding. Eleven elite male America's Cup sailors (33.9 +/- 5.5 yr, 97.8 +/- 12.5 kg, 186.0 +/- 7.1 cm) who performed grinding as part of their on-board role with extensive strength training experience participated in this study. Muscular performance testing examined the force, velocity, and power capabilities of the upper-body musculature, with upper-body push (bench press) and pull (bench pull) movements performed across loads of 10-100% of 1 repetition maximum (1RM). Functional grinding performance was examined for both forward and backward grinding and at 2 different resistances (moderate = 48 N x m, heavy = 68 N x m) using a land-based ergometer. Bench press 1RM and maximum force capability were the measures demonstrating the strongest correlation with forward grinding performance (r = 0.88-0.99 and 0.87-0.99, respectively), with the relationship increasing with grinding load. For backward grinding, there was a very strong relationship with bench pull maximum power (r = 0.85-0.98) in addition to 1RM (r = 0.90-0.95) and maximum force (r = 0.87-0.95). It appears that although maximal strength is a crucial muscular performance characteristic for grinding performance in all conditions, for backward grinding, there is the additional need to focus on the development of speed strength/power to maximize performance gains. This information was used by the Emirates Team New Zealand physical conditioner to develop a conditioning intervention to help improve grinding performance.

Kinematics and kinetics of the bench-press and bench-pull exercises in a strength-trained sporting population.

PubMed

Pearson, Simon N; Cronin, John B; Hume, Patria A; Slyfield, David

2009-09-01

Understanding how loading affects power production in resistance training is a key step in identifying the most optimal way of training muscular power - an essential trait in most sporting movements. Twelve elite male sailors with extensive strength-training experience participated in a comparison of kinematics and kinetics from the upper body musculature, with upper body push (bench press) and pull (bench pull) movements performed across loads of 10-100% of one repetition maximum (1RM). 1RM strength and force were shown to be greater in the bench press, while velocity and power outputs were greater for the bench pull across the range of loads. While power output was at a similar level for the two movements at a low load (10% 1RM), significantly greater power outputs were observed for the bench pull in comparison to the bench press with increased load. Power output (Pmax) was maximized at higher relative loads for both mean and peak power in the bench pull (78.6 +/- 5.7% and 70.4 +/- 5.4% of 1RM) compared to the bench press (53.3 +/- 1.7% and 49.7 +/- 4.4% of 1RM). Findings can most likely be attributed to differences in muscle architecture, which may have training implications for these muscles.

The effect of recovery time on strength performance following a high-intensity bench press workout in males and females.

PubMed

Judge, Lawrence W; Burke, Jeanmarie R

2010-06-01

To determine the effects of training sessions, involving high-resistance, low-repetition bench press exercise, on strength recovery patterns, as a function of gender and training background. The subjects were 12 athletes (6 males and 6 females) and age-matched college students of both genders (4 males and 4 females). The subjects completed a 3-wk resistance training program involving a bench press exercise, 3 d/wk, to become familiar with the testing procedure. After the completion of the resistance training program, the subjects, on three consecutive weeks, participated in two testing sessions per week, baseline session and recovery session. During the testing sessions, subjects performed five sets of the bench press exercise at 50% to 100% of perceived five repetition maximum (5-RM). Following the weekly baseline sessions, subjects rested during a 4-, 24-, or 48-h recovery period. Strength measurements were estimates of one repetition maximum (1-RM), using equivalent percentages for the number of repetitions completed by the subject at the perceived 5-RM effort of the bench press exercise. The full-factorial ANOVA model revealed a Gender by Recovery Period by Testing Session interaction effect, F(2, 32) = 10.65; P < .05. Among male subjects, decreases in estimated 1-RM were detected at the 4- and 24-h recovery times. There were no differences in muscle strength among the female subjects, regardless of recovery time. For bench press exercises, using different recovery times of 48 h for males and 4 h for females may optimize strength development as a function of gender.

Changes in Maximal Strength, Velocity, and Power After 8 Weeks of Training With Pneumatic or Free Weight Resistance.

PubMed

Frost, David M; Bronson, Stefanie; Cronin, John B; Newton, Robert U

2016-04-01

Because free weight (FW) and pneumatic (PN) resistance are characterized by different inertial properties, training with either resistance could afford unique strength, velocity, and power adaptations. Eighteen resistance-trained men completed baseline tests to determine their FW and PN bench press 1 repetition maximum (1RM). During the FW session, 4 explosive repetitions were performed at loads of 15, 30, 45, 60, 75, and 90% 1RM to assess force, velocity, and power. Participants were then assigned to a FW or PN training group, which involved three 90-minute sessions per week for 8 weeks. Both intervention groups completed identical periodized programs with the exception of the resistance used to perform all bench press movements. Free weight participants significantly increased their FW and PN 1RM (10.4 and 9.4%), and maximum (any load) force (9.8%), velocity (11.6%), and power (22.5%). Pneumatic-trained participants also exhibited increases in FW and PN 1RM (11.6 and 17.5%), and maximum force (8.4%), velocity (13.6%), and power (33.4%). Both interventions improved peak barbell velocity at loads of 15 and 30% 1RM; however, only the PN-trained individuals displayed improvements in peak force and power at these same loads. Training with PN resistance may offer advantages if attempting to improve power at lighter relative loads by affording an opportunity to consistently achieve higher accelerations and velocities (F = ma), in comparison with FW. Exploiting the inertial properties of the resistance, whether mass, elastic or PN, could afford an opportunity to develop mixed-method training strategies and/or elicit unique neuromuscular adaptations to suit the specific needs of athletes from sports characterized by varying demands.

Elastic Bands as a Component of Periodized Resistance Training.

PubMed

Joy, Jordan M; Lowery, Ryan P; Oliveira de Souza, Eduardo; Wilson, Jacob M

2016-08-01

Joy, JM, Lowery, RP, Oliveira de Souza, E, and Wilson, JM. Elastic bands as a component of periodized resistance training. J Strength Cond Res 30(8): 2100-2106, 2016-Variable resistance training (VRT) has recently become a component of strength and conditioning programs. Prior research has demonstrated increases in power and/or strength using low loads of variable resistance. However, no study has examined using high loads of variable resistance as a part of a periodized training protocol to examine VRT within the context of a periodized training program and to examine a greater load of variable resistance than has been examined in prior research. Fourteen National Collegiate Athletic Association division II male basketball players were recruited for this study. Athletes were divided equally into either a variable resistance or control group. The variable resistance group added 30% of their 1 repetition maximum (1RM) as band tension to their prescribed weight 1 session per week. Rate of power development (RPD), peak power, strength, body composition, and vertical jump height were measured pretreatment and posttreatment. No baseline differences were observed between groups for any measurement of strength, power, or body composition. A significant group by time interaction was observed for RPD, in which RPD was greater in VRT posttraining than in the control group. Significant time effects were observed for all other variables including squat 1RM, bench press 1RM, deadlift 1RM, clean 3RM, vertical jump, and lean mass. Although there were no significant group ×-time interactions, the VRT group's percent changes and effect sizes indicate a larger treatment effect in the squat and bench press 1RM values and the vertical jump performed on the force plate and vertec. These results suggest that when using variable resistance as a component of a periodized training program, power and strength can be enhanced. Therefore, athletes who add variable resistance to 1 training session per week may enhance their athletic performance.

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.

Biomechanical, anthropometric, and psychological determinants of barbell back squat strength.

PubMed

Vigotsky, Andrew D; Bryanton, Megan A; Nuckols, Greg; Beardsley, Chris; Contreras, Bret; Evans, Jessica; Schoenfeld, Brad J

2018-02-27

Previous investigations of strength have only focused on biomechanical or psychological determinants, while ignoring the potential interplay and relative contributions of these variables. The purpose of this study was to investigate the relative contributions of biomechanical, anthropometric, and psychological variables to the prediction of maximum parallel barbell back squat strength. Twenty-one college-aged participants (male = 14; female = 7; age = 23 ± 3 years) reported to the laboratory for two visits. The first visit consisted of anthropometric, psychometric, and parallel barbell back squat one-repetition maximum (1RM) testing. On the second visit, participants performed isometric dynamometry testing for the knee, hip, and spinal extensors in a sticking point position-specific manner. Multiple linear regression and correlations were used to investigate the combined and individual relationships between biomechanical, anthropometric, and psychological variables and squat 1RM. Multiple regression revealed only one statistically predictive determinant: fat free mass normalized to height (standardized estimate ± SE = 0.6 ± 0.3; t(16) = 2.28; p = 0.037). Correlation coefficients for individual variables and squat 1RM ranged from r = -0.79-0.83, with biomechanical, anthropometric, experiential, and sex predictors showing the strongest relationships, and psychological variables displaying the weakest relationships. These data suggest that back squat strength in a heterogeneous population is multifactorial and more related to physical rather than psychological variables.

Psychological correlates of performance in female athletes during a 12-week off-season strength and conditioning program.

PubMed

Jones, Margaret T; Matthews, Tracey D; Murray, Mimi; Van Raalte, Judy; Jensen, Barbara E

2010-03-01

Examination of the relationship between performance testing and psychological measures before and after a 12-week strength and conditioning program was the study's purpose. Female NCAA Division-III soccer (n = 28), field hockey (n = 28), and softball (n = 19) athletes completed pre- and post-testing held 12 weeks apart. On day 1, athletes completed informed consent, 3 psychological measures (Profile of Mood States [POMS], Physical Self Perception Profile [PSPP], and Athlete's Self Perception of Physical Abilities [ASPPA]), and 2 strength tests (1 repetition maximum [1RM] bench, 1RM back squat). Day 2 consisted of the 30-yd sprint, pro agility run (PRO), vertical jump (VJ), and standing long jump (SLJ). All sports improved (p < 0.01) in 1RM bench and squat and reported increases in perceived Physical Strength on the PSPP (p < 0.01). Soccer athletes improved (p < 0.01) in VJ, SLJ, and PRO (p < 0.05). No differences were found in POMS scores. The POMS scores indicated that the athletes were not overtrained or experiencing staleness. A series of correlations showed relationships between physical and psychological measures. Specifically, Physical Strength was correlated with 1RM upper-body (r = 0.49, p < 0.01) and lower-body (r = 0.42, p < 0.01) strength. The PSPP Physical Strength was correlated with ASPPA ratings of upper-body (r = 0.68, p < 0.01) and lower-body (r = 0.57, p < 0.01) strength. The PSPP Sport Competence correlated with ASPPA ratings of power (r = 0.45, p < 0.01) and PRO (r = 0.38, p < 0.05). The study's results highlight the benefits of strength and conditioning. Furthermore, these results demonstrate how physical changes are related to athletes' physical self-perceptions and self-assessment of ability within their teams.

Muscular Strength and Power in 3-to 7-Year-Old Children.

PubMed

Fry, Andrew C; Irwin, Carol C; Nicoll, Justin X; Ferebee, David E

2015-08-01

To determine absolute and relative (adjusted for body mass) strength, mean power, and mean velocity for upper and lower body resistance exercises, forty-seven young boys and girls participated in maximal strength testing. Healthy young boys and girls, ages 3- to 7-years old, were tested for one-repetition maximum (1-RM) strength, and 70% of 1-RM to determine mean power and mean velocity on the chest press and leg press exercises. Adult weight machines were modified to accommodate the smaller size and lower strength levels of the children. A 2 × 4 (sex × age) ANOVA was used to determine age and sex differences in performance. No interaction or sex differences were observed for any variable at any age. 1-RM strength, mean power, and mean velocity significantly increased across ages (p ≤ .05). When adjusted for body mass, the changes were insignificant, with one exception. Relative mean power for the bench press increased with age. Data indicated children from 3-7 years of age are capable of performing strength and power tests, but may require more attempts at maximal loads compared with adults. It appears that muscular strength and velocity during this stage of development are primarily dependent on increasing body mass, whereas power is influenced by additional variable(s).

The Effects of Multiple-Joint Isokinetic Resistance Training on Maximal Isokinetic and Dynamic Muscle Strength and Local Muscular Endurance.

PubMed

Ratamess, Nicholas A; Beller, Noah A; Gonzalez, Adam M; Spatz, Gregory E; Hoffman, Jay R; Ross, Ryan E; Faigenbaum, Avery D; Kang, Jie

2016-03-01

The transfer of training effects of multiple-joint isokinetic resistance training to dynamic exercise performance remain poorly understood. Thus, the purpose of the present study was to investigate the magnitude of isokinetic and dynamic one repetition-maximum (1RM) strength and local muscular endurance increases after 6 weeks of multiple-joint isokinetic resistance training. Seventeen women were randomly assigned to either an isokinetic resistance training group (IRT) or a non-exercising control group (CTL). The IRT group underwent 6 weeks of training (2 days per week) consisting of 5 sets of 6-10 repetitions at 75-85% of subjects' peak strength for the isokinetic chest press and seated row exercises at an average linear velocity of 0.15 m s(-1) [3-sec concentric (CON) and 3-sec eccentric (ECC) phases]. Peak CON and ECC force during the chest press and row, 1RM bench press and bent-over row, and maximum number of modified push-ups were assessed pre and post training. A 2 x 2 analysis of variance with repeated measures and Tukey's post hoc tests were used for data analysis. The results showed that 1RM bench press (from 38.6 ± 6.7 to 43.0 ± 5.9 kg), 1RM bent-over row (from 40.4 ± 7.7 to 45.5 ± 7.5 kg), and the maximal number of modified push-ups (from 39.5 ± 13.6 to 55.3 ± 13.1 repetitions) increased significantly only in the IRT group. Peak isokinetic CON and ECC force in the chest press and row significantly increased in the IRT group. No differences were shown in the CTL group for any measure. These data indicate 6 weeks of multiple-joint isokinetic resistance training increases dynamic muscle strength and local muscular endurance performance in addition to specific isokinetic strength gains in women. Key pointsMultiple-joint isokinetic resistance training increases dynamic maximal muscular strength, local muscular endurance, and maximal isokinetic strength in women.Multiple-joint isokinetic resistance training increased 1RM strength in the bench press (by 10.2%), bent-over barbell row (by 11.2%), and maximal modified push-up performance (by 28.6%) indicating a carryover of training effects to dynamic exercise performance.The carryover effects may be attractive to strength training and conditioning professionals seeking to include alternative modalities such as multiple-joint isokinetic dynamometers to resistance training programs.

The Effects of Multiple-Joint Isokinetic Resistance Training on Maximal Isokinetic and Dynamic Muscle Strength and Local Muscular Endurance

PubMed Central

Ratamess, Nicholas A.; Beller, Noah A.; Gonzalez, Adam M.; Spatz, Gregory E.; Hoffman, Jay R.; Ross, Ryan E.; Faigenbaum, Avery D.; Kang, Jie

2016-01-01

The transfer of training effects of multiple-joint isokinetic resistance training to dynamic exercise performance remain poorly understood. Thus, the purpose of the present study was to investigate the magnitude of isokinetic and dynamic one repetition-maximum (1RM) strength and local muscular endurance increases after 6 weeks of multiple-joint isokinetic resistance training. Seventeen women were randomly assigned to either an isokinetic resistance training group (IRT) or a non-exercising control group (CTL). The IRT group underwent 6 weeks of training (2 days per week) consisting of 5 sets of 6-10 repetitions at 75-85% of subjects’ peak strength for the isokinetic chest press and seated row exercises at an average linear velocity of 0.15 m s-1 [3-sec concentric (CON) and 3-sec eccentric (ECC) phases]. Peak CON and ECC force during the chest press and row, 1RM bench press and bent-over row, and maximum number of modified push-ups were assessed pre and post training. A 2 x 2 analysis of variance with repeated measures and Tukey’s post hoc tests were used for data analysis. The results showed that 1RM bench press (from 38.6 ± 6.7 to 43.0 ± 5.9 kg), 1RM bent-over row (from 40.4 ± 7.7 to 45.5 ± 7.5 kg), and the maximal number of modified push-ups (from 39.5 ± 13.6 to 55.3 ± 13.1 repetitions) increased significantly only in the IRT group. Peak isokinetic CON and ECC force in the chest press and row significantly increased in the IRT group. No differences were shown in the CTL group for any measure. These data indicate 6 weeks of multiple-joint isokinetic resistance training increases dynamic muscle strength and local muscular endurance performance in addition to specific isokinetic strength gains in women. Key points Multiple-joint isokinetic resistance training increases dynamic maximal muscular strength, local muscular endurance, and maximal isokinetic strength in women. Multiple-joint isokinetic resistance training increased 1RM strength in the bench press (by 10.2%), bent-over barbell row (by 11.2%), and maximal modified push-up performance (by 28.6%) indicating a carryover of training effects to dynamic exercise performance. The carryover effects may be attractive to strength training and conditioning professionals seeking to include alternative modalities such as multiple-joint isokinetic dynamometers to resistance training programs. PMID:26957924

The use of the isometric squat as a measure of strength and explosiveness.

PubMed

Bazyler, Caleb D; Beckham, George K; Sato, Kimitake

2015-05-01

The isometric squat has been used to detect changes in kinetic variables as a result of training; however, controversy exists in its application to dynamic multijoint tasks. Thus, the purpose of this study was to further examine the relationship between isometric squat kinetic variables and isoinertial strength measures. Subjects (17 men, 1-repetition maximum [1RM]: 148.2 ± 23.4 kg) performed squats 2 d · wk(-1) for 12 weeks and were tested on 1RM squat, 1RM partial squat, and isometric squat at 90° and 120° of knee flexion. Test-retest reliability was very good for all isometric measures (intraclass correlation coefficients > 0.90); however, rate of force development 250 milliseconds at 90° and 120° seemed to have a higher systematic error (relative technical error of measurement = 8.12%, 9.44%). Pearson product-moment correlations indicated strong relationships between isometric peak force at 90° (IPF 90°) and 1RM squat (r = 0.86), and IPF 120° and 1RM partial squat (r = 0.79). Impulse 250 milliseconds (IMP) at 90° and 120° exhibited moderate to strong correlations with 1RM squat (r = 0.70, 0.58) and partial squat (r = 0.73, 0.62), respectively. Rate of force development at 90° and 120° exhibited weak to moderate correlations with 1RM squat (r = 0.55, 0.43) and partial squat (r = 0.32, 0.42), respectively. These findings demonstrate a degree of joint angle specificity to dynamic tasks for rapid and peak isometric force production. In conclusion, an isometric squat performed at 90° and 120° is a reliable testing measure that can provide a strong indication of changes in strength and explosiveness during training.

The acute effects of a caffeine-containing supplement on strength, muscular endurance, and anaerobic capabilities.

PubMed

Beck, Travis W; Housh, Terry J; Schmidt, Richard J; Johnson, Glen O; Housh, Dona J; Coburn, Jared W; Malek, Moh H

2006-08-01

The purpose of this study was to examine the acute effects of a caffeine-containing supplement on upper- and lower-body strength and muscular endurance as well as anaerobic capabilities. Thirty-seven resistance-trained men (mean +/- SD, age: 21 +/- 2 years) volunteered to participate in this study. On the first laboratory visit, the subjects performed 2 Wingate Anaerobic Tests (WAnTs) to determine peak power (PP) and mean power (MP), as well as tests for 1 repetition maximum (1RM), dynamic constant external resistance strength, and muscular endurance (TOTV; total volume of weight lifted during an endurance test with 80% of the 1RM) on the bilateral leg extension (LE) and free-weight bench press (BP) exercises. Following a minimum of 48 hours of rest, the subjects returned to the laboratory for the second testing session and were randomly assigned to 1 of 2 groups: a supplement group (SUPP; n = 17), which ingested a caffeine-containing supplement, or a placebo group (PLAC; n = 20), which ingested a cellulose placebo. One hour after ingesting either the caffeine-containing supplement or the placebo, the subjects performed 2 WAnTs and were tested for 1RM strength and muscular endurance on the LE and BP exercises. The results indicated that there was a significant (p < 0.05) increase in BP 1RM for the SUPP group, but not for the PLAC group. The caffeine-containing supplement had no effect, however, on LE 1RM, LE TOTV, BP TOTV, PP, and MP. Thus, the caffeine-containing supplement may be an effective supplement for increasing upper-body strength and, therefore, could be useful for competitive and recreational athletes who perform resistance training.

Low-load bench press and push-up induce similar muscle hypertrophy and strength gain.

PubMed

Kikuchi, Naoki; Nakazato, Koichi

2017-06-01

To investigate the effect of push-up training with a similar load of to 40% of 1- repetition maximumal (1RM) bench press on muscle hypertrophy and strength gain in men. Eighteen male participants (age, 20.2 ± 0.73 years, range: 19-22 years, height: 169.8 ± 4.4 cm, weight: 64.5 ± 4.7 kg) were randomly assigned to one of two experimental groups: bench press at 40%1RM (bench-press group, n = 9) or push-ups with position adjusted (e.g. kneeling) to the same load of bench-press 40%1RM (push-up group, n = 9), performed twice per week for 8 weeks. Muscle thickness at three sites (biceps, triceps, and pectoralis major), bench-press 1RM, maximum repetition at 40%1RM, and power output (medicine ball throw) were measured before and after the training period. Significant increases in 1RM and muscle thickness (triceps and pectoralis major) were observed in bench-press group (1RM, from 60.0 ± 12.1 kg to 65.0 ± 12.1 kg, p < 0.01; triceps, from 26.3 ± 3.7 mm to 27.8 ± 3.8 mm, p < 0.01; pectoralis major, from 17.0 ± 2.8 mm to 20.8 ± 4.8 mm, p < 0.01) and in the push-up group (1RM, from 61.1 ± 12.2 kg to 64.2 ± 12.5 kg, p < 0.01; triceps, 27.7 ± 5.7 mm to 30.4 ± 6.6 mm, p < 0.01; pectoralis major, from 17.0 ± 2.8 mm to 20.8 ± 4.8 mm, p < 0.01). Biceps thickness significantly increased only in the bench-press group (28.4 ± 3.3 mm to 31.5 ± 3.7 mm, p < 0.01). Neither power output performance nor muscle endurance capacity changed in either group. Push-up exercise with similar load to 40%1RM bench press is comparably effective for muscle hypertrophy and strength gain over an 8-week training period.

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

PubMed

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

2006-11-01

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

Reliability of Maximal Strength Testing in Novice Weightlifters

NASA Technical Reports Server (NTRS)

Loehr, James A.; Lee, Stuart M. C.; Feiveson, Alan H.; Ploutz-Snyder, Lori L.

2009-01-01

The one repetition maximum (1RM) is a criterion measure of muscle strength. However, the reliability of 1RM testing in novice subjects has received little attention. Understanding this information is crucial to accurately interpret changes in muscle strength. To evaluate the test-retest reliability of a squat (SQ), heel raise (HR), and deadlift (DL) 1RM in novice subjects. Twenty healthy males (31 plus or minus 5 y, 179.1 plus or minus 6.1 cm, 81.4 plus or minus 10.6 kg) with no weight training experience in the previous six months participated in four 1RM testing sessions, with each session separated by 5-7 days. SQ and HR 1RM were conducted using a smith machine; DL 1RM was assessed using free weights. Session 1 was considered a familiarization and was not included in the statistical analyses. Repeated measures analysis of variance with Tukey fs post-hoc tests were used to detect between-session differences in 1RM (p.0.05). Test-retest reliability was evaluated by intraclass correlation coefficients (ICC). During Session 2, the SQ and DL 1RM (SQ: 90.2 }4.3, DL: 75.9 }3.3 kg) were less than Session 3 (SQ: 95.3 }4.1, DL: 81.5 plus or minus 3.5 kg) and Session 4 (SQ: 96.6 }4.0, DL: 82.4 }3.9 kg), but there were no differences between Session 3 and Session 4. HR 1RM measured during Session 2 (150.1 }3.7 kg) and Session 3 (152.5 }3.9 kg) were not different from one another, but both were less than Session 4 (157.5 }3.8 kg). The reliability (ICC) of 1RM measures for Sessions 2-4 were 0.88, 0.83, and 0.87, for SQ, HR, and DL, respectively. When considering only Sessions 3 and 4, the reliability was 0.93, 0.91, and 0.86 for SQ, HR, and DL, respectively. One familiarization session and 2 test sessions (for SQ and DL) were required to obtain excellent reliability (ICC greater than or equal to 0.90) in 1RM values with novice subjects. We were unable to attain this level of reliability following 3 HR testing sessions therefore additional sessions may be required to obtain an ICC of greater than or equal to 0.90. Future resistive exercise studies should consider the reliability of specific measures to ensure that changes in strength with training are attributable to training and not learning effects associated with 1RM testing.

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.

Short-Term Effects of Different Loading Schemes in Fitness-Related Resistance Training.

PubMed

Eifler, Christoph

2016-07-01

Eifler, C. Short-term effects of different loading schemes in fitness-related resistance training. J Strength Cond Res 30(7): 1880-1889, 2016-The purpose of this investigation was to analyze the short-term effects of different loading schemes in fitness-related resistance training and to identify the most effective loading method for advanced recreational athletes. The investigation was designed as a longitudinal field-test study. Two hundred healthy mature subjects with at least 12 months' experience in resistance training were randomized in 4 samples of 50 subjects each. Gender distribution was homogenous in all samples. Training effects were quantified by 10 repetition maximum (10RM) and 1 repetition maximum (1RM) testing (pre-post-test design). Over a period of 6 weeks, a standardized resistance training protocol with 3 training sessions per week was realized. Testing and training included 8 resistance training exercises in a standardized order. The following loading schemes were randomly matched to each sample: constant load (CL) with constant volume of repetitions, increasing load (IL) with decreasing volume of repetitions, decreasing load (DL) with increasing volume of repetitions, daily changing load (DCL), and volume of repetitions. For all loading schemes, significant strength gains (p < 0.001) could be noted for all resistance training exercises and both dependent variables (10RM, 1RM). In all cases, DCL obtained significantly higher strength gains (p < 0.001) than CL, IL, and DL. There were no significant differences in strength gains between CL, IL, and DL. The present data indicate that resistance training following DCL is more effective for advanced recreational athletes than CL, IL, or DL. Considering that DCL is widely unknown in fitness-related resistance training, the present data indicate, there is potential for improving resistance training in commercial fitness clubs.

Assessment and monitoring of ballistic and maximal upper-body strength qualities in athletes.

PubMed

Young, Kieran P; Haff, G Gregory; Newton, Robert U; Gabbett, Tim J; Sheppard, Jeremy M

2015-03-01

To evaluate whether the dynamic strength index (DSI: ballistic peak force/isometric peak force) could be effectively used to guide specific training interventions and detect training-induced changes in maximal and ballistic strength. Twenty-four elite male athletes were assessed in the isometric bench press and a 45% 1-repetition-maximum (1RM) ballistic bench throw using a force plate and linear position transducer. The DSI was calculated using the peak force values obtained during the ballistic bench throw and isometric bench press. Athletes were then allocated into 2 groups as matched pairs based on their DSI and strength in the 1RM bench press. Over the 5 wk of training, athletes performed either high-load (80-100% 1RM) bench press or moderate-load (40-55% 1RM) ballistic bench throws. The DSI was sensitive to disparate training methods, with the bench-press group increasing isometric bench-press peak force (P=.035, 91% likely), and the ballistic-bench-throw group increasing bench-throw peak force to a greater extent (P≤.001, 83% likely). A significant increase (P≤.001, 93% likely) in the DSI was observed for both groups. The DSI can be used to guide specific training interventions and can detect training-induced changes in isometric bench-press and ballistic bench-throw peak force over periods as short as 5 wk.

The effects of short-cycle sprints on power, strength, and salivary hormones in elite rugby players.

PubMed

Crewther, Blair T; Cook, Christian J; Lowe, Tim E; Weatherby, Robert P; Gill, Nicholas

2011-01-01

This study examined the effects of short-cycle sprints on power, strength, and salivary hormones in elite rugby players. Thirty male rugby players performed an upper-body power and lower-body strength (UPLS) and/or a lower-body power and upper-body strength (LPUS) workout using a crossover design (sprint vs. control). A 40-second upper-body or lower-body cycle sprint was performed before the UPLS and LPUS workouts, respectively, with the control sessions performed without the sprints. Bench throw (BT) power and box squat (BS) 1 repetition maximum (1RM) strength were assessed in the UPLS workout, and squat jump (SJ) power and bench press (BP) 1RM strength were assessed in the LPUS workout. Saliva was collected across each workout and assayed for testosterone (Sal-T) and cortisol (Sal-C). The cycle sprints improved BS (2.6 ± 1.2%) and BP (2.8 ± 1.0%) 1RM but did not affect BT and SJ power. The lower-body cycle sprint produced a favorable environment for the BS by elevating Sal-T concentrations. The upper-body cycle sprint had no hormonal effect, but the workout differences (%) in Sal-T (r = -0.59) and Sal-C (r = 0.42) concentrations correlated to the BP, along with the Sal-T/C ratio (r = -0.49 to -0.66). In conclusion, the cycle sprints improved the BP and BS 1RM strength of elite rugby players but not power output in the current format. The improvements noted may be explained, in part, by the changes in absolute or relative hormone concentrations. These findings have practical implications for prescribing warm-up and training exercises.

Reliability and validity of two isometric squat tests.

PubMed

Blazevich, Anthony J; Gill, Nicholas; Newton, Robert U

2002-05-01

The purpose of the present study was first to examine the reliability of isometric squat (IS) and isometric forward hack squat (IFHS) tests to determine if repeated measures on the same subjects yielded reliable results. The second purpose was to examine the relation between isometric and dynamic measures of strength to assess validity. Fourteen male subjects performed maximal IS and IFHS tests on 2 occasions and 1 repetition maximum (1-RM) free-weight squat and forward hack squat (FHS) tests on 1 occasion. The 2 tests were found to be highly reliable (intraclass correlation coefficient [ICC](IS) = 0.97 and ICC(IFHS) = 1.00). There was a strong relation between average IS and 1-RM squat performance, and between IFHS and 1-RM FHS performance (r(squat) = 0.77, r(FHS) = 0.76; p < 0.01), but a weak relation between squat and FHS test performances (r < 0.55). There was also no difference between observed 1-RM values and those predicted by our regression equations. Errors in predicting 1-RM performance were in the order of 8.5% (standard error of the estimate [SEE] = 13.8 kg) and 7.3% (SEE = 19.4 kg) for IS and IFHS respectively. Correlations between isometric and 1-RM tests were not of sufficient size to indicate high validity of the isometric tests. Together the results suggest that IS and IFHS tests could detect small differences in multijoint isometric strength between subjects, or performance changes over time, and that the scores in the isometric tests are well related to 1-RM performance. However, there was a small error when predicting 1-RM performance from isometric performance, and these tests have not been shown to discriminate between small changes in dynamic strength. The weak relation between squat and FHS test performance can be attributed to differences in the movement patterns of the tests

Reliability and Validity of the Load-Velocity Relationship to Predict the 1RM Back Squat.

PubMed

Banyard, Harry G; Nosaka, Kazunori; Haff, G Gregory

2017-07-01

Banyard, HG, Nosaka, K, and Haff, GG. Reliability and validity of the load-velocity relationship to predict the 1RM back squat. J Strength Cond Res 31(7): 1897-1904, 2017-This study investigated the reliability and validity of the load-velocity relationship to predict the free-weight back squat one repetition maximum (1RM). Seventeen strength-trained males performed three 1RM assessments on 3 separate days. All repetitions were performed to full depth with maximal concentric effort. Predicted 1RMs were calculated by entering the mean concentric velocity of the 1RM (V1RM) into an individualized linear regression equation, which was derived from the load-velocity relationship of 3 (20, 40, 60% of 1RM), 4 (20, 40, 60, 80% of 1RM), or 5 (20, 40, 60, 80, 90% of 1RM) incremental warm-up sets. The actual 1RM (140.3 ± 27.2 kg) was very stable between 3 trials (ICC = 0.99; SEM = 2.9 kg; CV = 2.1%; ES = 0.11). Predicted 1RM from 5 warm-up sets up to and including 90% of 1RM was the most reliable (ICC = 0.92; SEM = 8.6 kg; CV = 5.7%; ES = -0.02) and valid (r = 0.93; SEE = 10.6 kg; CV = 7.4%; ES = 0.71) of the predicted 1RM methods. However, all predicted 1RMs were significantly different (p ≤ 0.05; ES = 0.71-1.04) from the actual 1RM. Individual variation for the actual 1RM was small between trials ranging from -5.6 to 4.8% compared with the most accurate predictive method up to 90% of 1RM, which was more variable (-5.5 to 27.8%). Importantly, the V1RM (0.24 ± 0.06 m·s) was unreliable between trials (ICC = 0.42; SEM = 0.05 m·s; CV = 22.5%; ES = 0.14). The load-velocity relationship for the full depth free-weight back squat showed moderate reliability and validity but could not accurately predict 1RM, which was stable between trials. Thus, the load-velocity relationship 1RM prediction method used in this study cannot accurately modify sessional training loads because of large V1RM variability.

Evaluating Upper-Body Strength and Power From a Single Test: The Ballistic Push-up.

PubMed

Wang, Ran; Hoffman, Jay R; Sadres, Eliahu; Bartolomei, Sandro; Muddle, Tyler W D; Fukuda, David H; Stout, Jeffrey R

2017-05-01

Wang, R, Hoffman, JR, Sadres, E, Bartolomei, S, Muddle, TWD, Fukuda, DH, and Stout, JR. Evaluating upper-body strength and power from a single test: the ballistic push-up. J Strength Cond Res 31(5): 1338-1345, 2017-The purpose of this study was to examine the reliability of the ballistic push-up (BPU) exercise and to develop a prediction model for both maximal strength (1 repetition maximum [1RM]) in the bench press exercise and upper-body power. Sixty recreationally active men completed a 1RM bench press and 2 BPU assessments in 3 separate testing sessions. Peak and mean force, peak and mean rate of force development, net impulse, peak velocity, flight time, and peak and mean power were determined. Intraclass correlation coefficients were used to examine the reliability of the BPU. Stepwise linear regression was used to develop 1RM bench press and power prediction equations. Intraclass correlation coefficient's ranged from 0.849 to 0.971 for the BPU measurements. Multiple regression analysis provided the following 1RM bench press prediction equation: 1RM = 0.31 × Mean Force - 1.64 × Body Mass + 0.70 (R = 0.837, standard error of the estimate [SEE] = 11 kg); time-based power prediction equation: Peak Power = 11.0 × Body Mass + 2012.3 × Flight Time - 338.0 (R = 0.658, SEE = 150 W), Mean Power = 6.7 × Body Mass + 1004.4 × Flight Time - 224.6 (R = 0.664, SEE = 82 W); and velocity-based power prediction equation: Peak Power = 8.1 × Body Mass + 818.6 × Peak Velocity - 762.0 (R = 0.797, SEE = 115 W); Mean Power = 5.2 × Body Mass + 435.9 × Peak Velocity - 467.7 (R = 0.838, SEE = 57 W). The BPU is a reliable test for both upper-body strength and power. Results indicate that the mean force generated from the BPU can be used to predict 1RM bench press, whereas peak velocity and flight time measured during the BPU can be used to predict upper-body power. These findings support the potential use of the BPU as a valid method to evaluate upper-body strength and power.

Comparison of Periodized and Non-Periodized Resistance Training on Maximal Strength: A Meta-Analysis.

PubMed

Williams, Tyler D; Tolusso, Danilo V; Fedewa, Michael V; Esco, Michael R

2017-10-01

Periodization is a logical method of organizing training into sequential phases and cyclical time periods in order to increase the potential for achieving specific performance goals while minimizing the potential for overtraining. Periodized resistance training plans are proposed to be superior to non-periodized training plans for enhancing maximal strength. The primary aim of this study was to examine the previous literature comparing periodized resistance training plans to non-periodized resistance training plans and determine a quantitative estimate of effect on maximal strength. All studies included in the meta-analysis met the following inclusion criteria: (1) peer-reviewed publication; (2) published in English; (3) comparison of a periodized resistance training group to a non-periodized resistance training group; (4) maximal strength measured by 1-repetition maximum (1RM) squat, bench press, or leg press. Data were extracted and independently coded by two authors. Random-effects models were used to aggregate a mean effect size (ES), 95% confidence intervals (CIs) and potential moderators. The cumulative results of 81 effects gathered from 18 studies published between 1988 and 2015 indicated that the magnitude of improvement in 1RM following periodized resistance training was greater than non-periodized resistance training (ES = 0.43, 95% CI 0.27-0.58; P < 0.001). Periodization model (β = 0.51; P = 0.0010), training status (β = -0.59; P = 0.0305), study length (β = 0.03; P = 0.0067), and training frequency (β = 0.46; P = 0.0123) were associated with a change in 1RM. These results indicate that undulating programs were more favorable for strength gains. Improvements in 1RM were greater among untrained participants. Additionally, higher training frequency and longer study length were associated with larger improvements in 1RM. These results suggest that periodized resistance training plans have a moderate effect on 1RM compared to non-periodized training plans. Variation in training stimuli appears to be vital for increasing maximal strength, and longer periods of higher training frequency may be preferred.

Strength After Bouts of Eccentric or Concentric Actions

NASA Technical Reports Server (NTRS)

Golden, Catherine L.; Dudley, Gary A.

1992-01-01

This study examined the influence of an initial bout of eccentric or concentric actions and a subsequent bout of eccentric actions on muscular strength. Twenty-four healthy males, 24-45 yr old, were placed in three groups that performed eccentric actions in bouts 1 and 2 (ECC/ECC, N = 8), concentric actions in bout 1, and eccentric actions in bout 2 (CON/ECC, N = 8) or served as controls (N = 8). Bouts involved unilateral actions with the left and right quadriceps femoris. Ten sets of 10 repetitions with an initial resistance equal to 85% of the eccentric or concentric one repetition maximum (1 RM) were performed for each bout. Three minutes of rest were given between sets and 3 wk between bouts. Two weeks before bout 1 and 1, 4, 7, and 10 d after bouts 1 and 2, eccentric and concentric 1 RM were measured for the right quadriceps femoris and a speed-torque relation established for the left quadriceps femoris. Eccentric and concentric 1 RM decreased (P less than 0.05) 32% 1 d after bout 1 for group ECC/ECC. The speed-torque relation was down-shifted (P less than 0.05) 38%. Eccentric 1 RM and eccentric and isometric torque returned to normal 6 d later. Concentric 1 RM and torque at 3.14 rad-s(exp -1) had not recovered on day 10 (-7% for both, P less than 0.05). Decreases in strength after bout 2 for group ECC/ECC only occurred on day 1 (-9% for concentric 1 RM and 16% downshift of the speed- torque relation). Group CONIECC showed the opposite responses; marked decreases in strength after bout 2 but not bout 1. The results indicate that the initial decrease in strength after performance of a novel bout of eccentric exercise is comparable for eccentric, concentric and isometric muscle actions. Recovery of strength, however, appears to occur more rapidly for eccentric and isometric actions. They suggest that performance of a prior bout of eccentric but not concentric actions, as done in this study, can essentially eradicate decreases in strength after a subsequent bout of eccentric exercise. It is suggested that neural factors are, in part, responsible for adaptations to eccentric exercise.

The effects of respiratory-muscle training on exercise in older women.

PubMed

Watsford, Mark; Murphy, Arona

2008-07-01

This research examined the effects of respiratory-muscle (RM) training on RM function and exercise performance in older women. Twenty-six women (60-69 yr of age) were assessed for spirometry, RM strength (maximal inspiratory and expiratory pressure), inspiratory-muscle endurance, and walking performance to a perceived exertion rating of "hard." They were randomly allocated to a threshold RM training group (RMT) or a nonexercising control group (CON) for 8 wk.After training, the 22% (inspiratory) and 30% (expiratory) improvements in RM strength in the RMT group were significantly higher than in the CON group (p < .05). The RMT group also displayed several significant performance improvements, including improved within-group treadmill performance time (12%) and reductions in submaximal heart rate (5%), percentage of maximum voluntary ventilation (16%), and perceived exertion for breathing (8%). RM training appears to improve RM function in older women. Furthermore, these improvements appear to be related to improved submaximal exercise performance.

Muscular Maximal Strength Indices and Bone Variables in a Group of Elderly Women.

PubMed

Nasr, Riad; Al Rassy, Nathalie; Watelain, Eric; Matta, Joseph; Frenn, Fabienne; Rizkallah, Maroun; Maalouf, Ghassan; El Khoury, César; Berro, Abdel-Jalil; El Hage, Rawad

2018-03-22

The aim of the present study was to explore the relations between muscular maximal strength indices and bone parameters (bone mineral density [BMD], hip geometry indices, and trabecular bone score [TBS]) in a group of elderly women. This study included 35 healthy elderly women whose ages range between 65 and 75 yr (68.1 ± 3.1 yr). BMD (in gram per square centimeter) was determined for each individual by dual-energy X-ray absorptiometry at the whole body, lumbar spine (L1-L4), total hip (TH), and femoral neck (FN). L1-L4 TBS and hip geometry indices were also evaluated by dual-energy X-ray absorptiometry. Maximal muscle strength of bench press (1-repetition maximum [RM] bench press), maximal muscle strength of leg press (1-RM leg press), and handgrip were measured using validated methods. 1-RM bench press was positively correlated to TH BMD (r = 0.40; p < 0.05), FN BMD (r = 0.41; p < 0.05), FN section modulus (r = 0.33; p < 0.05), and FN cross-sectional moment of inertia (r = 0.35; p < 0.05). 1-RM leg press was positively correlated to TH BMD (r = 0.50; p < 0.01), FN BMD (r = 0.35; p < 0.05), FN cross-sectional area (r = 0.38; p < 0.05), and TBS (r = 0.37; p < 0.05). Handgrip was correlated only to FN cross-sectional moment of inertia (r = 0.43; p < 0.01). This study suggests that 1-RM bench press and 1-RM leg press are positive determinants of BMD in elderly women. Copyright © 2018 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

Early-phase musculoskeletal adaptations to different levels of eccentric resistance after 8 weeks of lower body training.

PubMed

English, Kirk L; Loehr, James A; Lee, Stuart M C; Smith, Scott M

2014-11-01

Eccentric muscle actions are important to the development of muscle mass and strength and may affect bone mineral density (BMD). This study's purpose was to determine the relative effectiveness of five different eccentric:concentric load ratios to increase musculoskeletal parameters during early adaptations to resistance training. Forty male subjects performed a supine leg press and calf press training program 3 days week(-1) for 8 weeks. Subjects were matched for pre-training leg press 1-repetition maximum strength (1-RM) and randomly assigned to one of five training groups. Concentric training load (% 1-RM) was constant across groups, but within groups, eccentric load was 0, 33, 66, 100, or 138% of concentric load. Muscle mass (dual energy X-ray absorptiometry; DXA), strength (1-RM), and BMD (DXA) were measured pre- and post-training. Markers of bone metabolism were assessed pre-, mid- and post-training. The increase in leg press 1-RM in the 138% group (20 ± 4%) was significantly greater (P < 0.05) than the 0% (8 ± 3%), 33% (8 ± 5%) and 66% (8 ± 4%) groups, but not the 100% group (13 ± 6 %; P = 0.15). All groups, except the 0% group, increased calf press 1-RM (P < 0.05). Leg lean mass and greater trochanter BMD were increased only in the 138% group (P < 0.05). Early-phase adaptations to eccentric overload training include increases in muscle mass and site-specific increases in BMD and muscle strength which are not present or are less with traditional and eccentric underload training. Eccentric overload provides a robust musculoskeletal stimulus that may benefit bedridden patients, individuals recovering from injury or illness, and astronauts during spaceflight.

Baseline strength can influence the ability of salivary free testosterone to predict squat and sprinting performance.

PubMed

Crewther, Blair T; Cook, Christian J; Gaviglio, Chris M; Kilduff, Liam P; Drawer, Scott

2012-01-01

The objective of this study was to determine if salivary free testosterone can predict an athlete's performance during back squats and sprints over time and the influence baseline strength on this relationship. Ten weight-trained male athletes were divided into 2 groups based on their 1 repetition maximum (1RM) squats, good squatters (1RM > 2.0 × body weight, n = 5) and average squatters (1RM < 1.9 × body weight, n = 5). The good squatters were stronger than the average squatters (p < 0.05). Each subject was assessed for squat 1RM and 10-m sprint times on 10 separate occasions over a 40-day period. A saliva sample was collected before testing and assayed for free testosterone and cortisol. The pooled testosterone correlations were strong and significant in the good squatters (r = 0.92 for squats, r = -0.87 for sprints, p < 0.01), but not significant for the average squatters (r = 0.35 for squats, r = -0.18 for sprints). Cortisol showed no significant correlations with 1RM squat and 10-m sprint performance, and no differences were identified between the 2 squatting groups. In summary, these results suggest that free testosterone is a strong individual predictor of squat and sprinting performance in individuals with relatively high strength levels but a poor predictor in less strong individuals. This information can assist coaches, trainers, and performance scientists working with stronger weight-trained athletes, for example, the preworkout measurement of free testosterone could indicate likely training outcomes or a readiness to train at a certain intensity level, especially if real-time measurements are made. Our results also highlight the need to separate group and individual hormonal data during the repeated testing of athletes with variable strength levels.

Test-Retest Reliability of Rating of Perceived Exertion and Agreement With 1-Repetition Maximum in Adults.

PubMed

Bove, Allyn M; Lynch, Andrew D; DePaul, Samantha M; Terhorst, Lauren; Irrgang, James J; Fitzgerald, G Kelley

2016-09-01

Study Design Clinical measurement. Background It has been suggested that rating of perceived exertion (RPE) may be a useful alternative to 1-repetition maximum (1RM) to determine proper resistance exercise dosage. However, the test-retest reliability of RPE for resistance exercise has not been determined. Additionally, prior research regarding the relationship between 1RM and RPE is conflicting. Objectives The purpose of this study was to (1) determine test-retest reliability of RPE related to resistance exercise and (2) assess agreement between percentages of 1RM and RPE during quadriceps resistance exercise. Methods A sample of participants with and without knee pathology completed a series of knee extension exercises and rated the perceived difficulty of each exercise on a 0-to-10 RPE scale, then repeated the procedure 1 to 2 weeks later for test-retest reliability. To determine agreement between RPE and 1RM, participants completed knee extension exercises at various percentages of their 1RM (10% to 130% of predicted 1RM) and rated the perceived difficulty of each exercise on a 0-to-10 RPE scale. Percent agreement was calculated between the 1RM and RPE at each resistance interval. Results The intraclass correlation coefficient indicated excellent test-retest reliability of RPE for quadriceps resistance exercises (intraclass correlation coefficient = 0.895; 95% confidence interval: 0.866, 0.918). Overall percent agreement between RPE and 1RM was 60%, but agreement was poor within the ranges that would typically be used for training (50% 1RM for muscle endurance, 70% 1RM and greater for strength). Conclusion Test-retest reliability of perceived exertion during quadriceps resistance exercise was excellent. However, agreement between the RPE and 1RM was poor, especially in common training zones for knee extensor strengthening. J Orthop Sports Phys Ther 2016;46(9):768-774. Epub 5 Aug 2016. doi:10.2519/jospt.2016.6498.

Maximum Dynamic Lower-Limb Strength Was Maintained During 24-Week Reduced Training Frequency in Previously Sedentary Older Women.

PubMed

Walker, Simon; Serrano, Javier; Van Roie, Evelien

2018-04-01

Walker, S, Serrano, J, and Van Roie, E. Maximum dynamic lower-limb strength was maintained during 24-week reduced training frequency in previously sedentary older women. J Strength Cond Res 32(4): 1063-1071, 2018-There is little study into the effects of reducing strength training below the recommended twice weekly frequency, particularly in older women, despite the possibility that individuals will encounter periods of reduced training frequency. The purpose of the present study was to determine the effects of a period of reduced training frequency on maximum strength and muscle mass of the lower limbs in comparison with the recommended training frequency of twice per week. After an initial 12-week period, where all subjects trained twice per week, a reduced strength training group (RST) trained once per week, whereas another strength training group (ST) continued to train twice per week for 24 weeks. A nontraining age-matched control group (CON) was used for comparison. All subjects were tested for leg press 1-repetition maximum (1RM), electromyogram (EMG) amplitude of vastus lateralis and medialis, and quadriceps cross-sectional area (CSA) measured by panoramic ultrasound at weeks 0, 12, and 36. Both ST and RST continued to increase 1RM during the reduced training frequency period compared with control (∼8% and ∼5% vs. ∼-3%, respectively; p ≤ 0.05). Accompanying these changes were significant increases in EMG amplitude in both ST and RST (p ≤ 0.05). However, the initial gains in quadriceps CSA made from week 0 to week 12 in RST were lost when training once per week (RST ∼-5%). Therefore, reduced training frequency in this population does not adversely affect maximum strength or muscle activity but can negatively affect muscle mass, even reversing training-induced gains. Older individuals not training at least twice per week may compromise potential increases in muscle mass, important in counteracting effects of aging.

Longer Interset Rest Periods Enhance Muscle Strength and Hypertrophy in Resistance-Trained Men.

PubMed

Schoenfeld, Brad J; Pope, Zachary K; Benik, Franklin M; Hester, Garrett M; Sellers, John; Nooner, Josh L; Schnaiter, Jessica A; Bond-Williams, Katherine E; Carter, Adrian S; Ross, Corbin L; Just, Brandon L; Henselmans, Menno; Krieger, James W

2016-07-01

Schoenfeld, BJ, Pope, ZK, Benik, FM, Hester, GM, Sellers, J, Nooner, JL, Schnaiter, JA, Bond-Williams, KE, Carter, AS, Ross, CL, Just, BL, Henselmans, M, and Krieger, JW. Longer interset rest periods enhance muscle strength and hypertrophy in resistance-trained men. J Strength Cond Res 30(7): 1805-1812, 2016-The purpose of this study was to investigate the effects of short rest intervals normally associated with hypertrophy-type training versus long rest intervals traditionally used in strength-type training on muscular adaptations in a cohort of young, experienced lifters. Twenty-one young resistance-trained men were randomly assigned to either a group that performed a resistance training (RT) program with 1-minute rest intervals (SHORT) or a group that employed 3-minute rest intervals (LONG). All other RT variables were held constant. The study period lasted 8 weeks with subjects performing 3 total body workouts a week comprised 3 sets of 8-12 repetition maximum (RM) of 7 different exercises per session. Testing was performed prestudy and poststudy for muscle strength (1RM bench press and back squat), muscle endurance (50% 1RM bench press to failure), and muscle thickness of the elbow flexors, triceps brachii, and quadriceps femoris by ultrasound imaging. Maximal strength was significantly greater for both 1RM squat and bench press for LONG compared to SHORT. Muscle thickness was significantly greater for LONG compared to SHORT in the anterior thigh, and a trend for greater increases was noted in the triceps brachii (p = 0.06) as well. Both groups saw significant increases in local upper body muscle endurance with no significant differences noted between groups. This study provides evidence that longer rest periods promote greater increases in muscle strength and hypertrophy in young resistance-trained men.

Modified Daily Undulating Periodization Model Produces Greater Performance Than a Traditional Configuration in Powerlifters.

PubMed

Zourdos, Michael C; Jo, Edward; Khamoui, Andy V; Lee, Sang-Rok; Park, Bong-Sup; Ormsbee, Michael J; Panton, Lynn B; Contreras, Robert J; Kim, Jeong-Su

2016-03-01

The primary aim of this study was to compare 2 daily undulating periodization (DUP) models on one-repetition maximum (1RM) strength in the squat, bench press, deadlift, total volume (TV) lifted, and temporal hormone response. Eighteen male, college-aged (21.1 ± 1.9 years) powerlifters participated in this study and were assigned to one of 2 groups: (a) traditional DUP training with a weekly training order: hypertrophy-specific, strength-specific, and power-specific training (HSP, n = 9) or (b) modified DUP training with a weekly training order: hypertrophy-specific, power-specific, and strength-specific training (HPS, n = 9). Both groups trained 3 nonconsecutive days per week for 6 weeks and performed the squat, bench press, and deadlift exercises. During hypertrophy and power sessions, subjects performed a fixed number of sets and repetitions but performed repetitions until failure at a given percentage during strength sessions to compare TV. Testosterone and cortisol were measured at pretesting and posttesting and before each strength-specific day. Hypertrophy, power, and strength produced greater TV in squat and bench press (p ≤ 0.05) than HSP, but not for deadlift (p > 0.05). For squat and deadlift, there was no difference between groups for 1RM (p > 0.05); however, HPS exhibited greater increases in 1RM bench press than HSP (p ≤ 0.05). Effect sizes (ES) showed meaningful differences (ES > 0.50) in favor of HPS for squat and bench press 1RM. Testosterone decreased (p ≤ 0.05) at weeks 5 and 6 and cortisol decline at weeks 3 and 4. However, neither hormone was different at posttesting compared with pretesting (p > 0.05). Our findings suggest that an HPS configuration of DUP has enhanced performance benefits compared with HSP.

Strength and Hypertrophy Adaptations Between Low- vs. High-Load Resistance Training: A Systematic Review and Meta-analysis.

PubMed

Schoenfeld, Brad J; Grgic, Jozo; Ogborn, Dan; Krieger, James W

2017-12-01

Schoenfeld, BJ, Grgic, J, Ogborn, D, and Krieger, JW. Strength and hypertrophy adaptations between low- vs. high-load resistance training: a systematic review and meta-analysis. J Strength Cond Res 31(12): 3508-3523, 2017-The purpose of this article was to conduct a systematic review of the current body of literature and a meta-analysis to compare changes in strength and hypertrophy between low- vs. high-load resistance training protocols. Searches of PubMed/MEDLINE, Cochrane Library, and Scopus were conducted for studies that met the following criteria: (a) an experimental trial involving both low-load training [≤60% 1 repetition maximum (1RM)] and high-load training (>60% 1RM); (b) with all sets in the training protocols being performed to momentary muscular failure; (c) at least one method of estimating changes in muscle mass or dynamic, isometric, or isokinetic strength was used; (d) the training protocol lasted for a minimum of 6 weeks; (e) the study involved participants with no known medical conditions or injuries impairing training capacity. A total of 21 studies were ultimately included for analysis. Gains in 1RM strength were significantly greater in favor of high- vs. low-load training, whereas no significant differences were found for isometric strength between conditions. Changes in measures of muscle hypertrophy were similar between conditions. The findings indicate that maximal strength benefits are obtained from the use of heavy loads while muscle hypertrophy can be equally achieved across a spectrum of loading ranges.

Blood flow restricted resistance training in older adults at risk of mobility limitations.

PubMed

Cook, Summer B; LaRoche, Dain P; Villa, Michelle R; Barile, Hannah; Manini, Todd M

2017-12-01

High-load resistance training (HL) may be contraindicated in older adults due to pre-existing health conditions (e.g. osteoarthritis). Low-load blood flow restricted (BFR) resistance training offers an alternative to HL with potentially similar strength improvement. To compare muscle strength, cross-sectional area (CSA), physical function, and quality of life (QOL) following 12-weeks of HL or BFR training in older adults at risk of mobility limitations. Thirty-six males and females (mean: 75.6years 95% confidence interval: [73.4-78.5], 1.67m [1.64-1.70], 74.3kg [69.8-78.8]) were randomly assigned to HL (70% of one repetition maximum [1-RM]) or low-load BFR (30% 1-RM coupled with a vascular restriction) exercise for the knee extensors and flexors twice per week for 12weeks. A control (CON) group performed light upper body resistance and flexibility training. Muscle strength, CSA of the quadriceps, 400-m walking speed, Short Physical Performance Battery (SPPB), and QOL were assessed before, midway and after training. Within 6-weeks of HL training, increases in all strength measures and CSA were evident and the gains were significantly greater than the CON group (P<0.05). The BFR group had strength increases in leg extension and leg press 1-RM tests, but were significantly lower in leg extension isometric maximum voluntary contraction (MVC) and leg extension 1-RM than the HL group (P<0.01). At 12-weeks HL and BFR training did not differ in MVC (P=0.14). Walking speed increased 4% among all training groups (P<0.01) and no changes were observed for overall SPPB score and QOL (P>0.05). Both training programs resulted in muscle CSA improvements and HL training had more pronounced strength gains than BFR training after 6-weeks and were more similar to BFR after 12-weeks of training. These changes in both groups did not transfer to improvements in QOL, SPPB, and walking speed. Since both programs result in strength and CSA gains, albeit at different rates, future research should consider using a combination of HL and BFR training in older adults with profound muscle weakness and mobility limitations. Copyright © 2017 Elsevier Inc. All rights reserved.

Optimal load for the peak power and maximal strength of the upper body in Brazilian Jiu-Jitsu athletes.

PubMed

da Silva, Bruno Victor C; Simim, Mário A de Moura; Marocolo, Moacir; Franchini, Emerson; da Mota, Gustavo R

2015-06-01

We determined the optimal load for the peak power output (PPO) during the bench press throw (BPT) in Brazilian Jiu-Jitsu (BJJ) athletes and compared the PPO and maximal strength between advanced (AD) and nonadvanced (NA) athletes. Twenty-eight BJJ athletes (24.8 ± 5.7 years) performed the BPT at loads of 30, 40, 50, and 60% of their 1 repetition maximum (RM) in a randomized order (5-minute rest between BPTs). The PPO was determined by measuring the barbell displacement by an accelerometer (Myotest). The absolute (F = 7.25; p < 0.001; effect size [ES] = 0.21) and relative intensities were different (F = 7.11; p < 0.001; ES = 0.21) between the AD and NA. There was also a group and intensity interaction effect (F = 2.79; p = 0.046; ES = 0.10), but the differences were centered around the AD group, which achieved higher values using 40% (p = 0.001) and 50% of the 1RM (p < 0.001) than the PPO with 60% of 1RM. The AD athletes presented with higher 1RM than NA (p ≤ 0.05; ES = 1.0), but there was no difference (p > 0.05) in the PPO (30-60% 1RM). A polynomial adjustment indicated that the optimal load was ∼42% of 1RM for all groups and subgroups (R from 0.82 to 0.99). Our results suggest that there can be (1RM) differences between AD and NA BJJ athletes; however, there is no difference in the muscle power between the AD and NA groups. Additionally, ∼42% of 1RM seems to be the optimal load for developing maximal power using the BPT for the BJJ athletes.

Effects of resistance training, detraining, and retraining on strength and functional capacity in elderly.

PubMed

Sakugawa, Raphael Luiz; Moura, Bruno Monteiro; Orssatto, Lucas Bet da Rosa; Bezerra, Ewertton de Souza; Cadore, Eduardo Lusa; Diefenthaeler, Fernando

2018-05-17

The interruption of training (detraining) results in loss of the gains acquired. Partial retention could occur after detraining, and variation in training stimuli may optimize retraining adaptations. To evaluate the effect of a resistance-retraining program on strength and functional capacity performance after a detraining period. Ten elderly men and women (63-68 years) completed 12 weeks of training, 16 weeks of detraining, and 8 weeks of retraining. One-repetition maximum (1-RM) at 45° leg press, maximum isometric knee extension torque, rate of torque development (RTD), 30-s sit-to-stand, timed up and go, and stair ascent and descent tests were assessed. The 1-RM increased after training (p < 0.01) and remained higher after a detraining period when compared to pre-training (p < 0.01). Post-retraining values were not different from post-training period (p > 0.05). For RTD and 30-s sit-to-stand, there was an increase after retraining when compared to pre-training values (p < 0.05). For timed up and go and stair ascent and descent, reductions were observed between pre-training and post-training periods (p < 0.05), only timed up and go increased after the detraining period (p < 0.01). After 16 weeks of detraining, the maximum strength did not return to baseline levels, and a retraining with explosive strength exercise sessions can recover maximum strength gains, RTD, and functional capacity at the same level obtained after a detraining period. The inclusion of an explosive strength session in retraining period improves RTD and 30-s sit-to-stand performance and can accelerate the recovery of strength after a detraining period.

Carbohydrate and Caffeine Mouth Rinses Do Not Affect Maximum Strength and Muscular Endurance Performance.

PubMed

Clarke, Neil D; Kornilios, Evangelos; Richardson, Darren L

2015-10-01

Oral carbohydrate (CHO) rinsing has beneficial effects on endurance performance and caffeine (CAF) mouth rinsing either independently or in conjunction with CHO may enhance sprinting performance. However, the effects of CHO and CAF mouth rinses on resistance exercise have not been examined previously. The purpose of this study was to investigate the effects of CHO and CAF rinsing on maximum strength and muscular endurance performance. Fifteen recreationally resistance-trained males completed an exercise protocol, which involved a 1 repetition maximum (RM) bench press followed by 60% of their 1RM to failure in a double-blind, randomized, counterbalanced crossover design. Before exercise, 25 ml of a 6% (15 g; 0.20 ± 0.02 g·kg(-1)) CHO, 1.2% (300 mg; 3.9 ± 0.3 mg·kg(-1)) CAF, carbohydrate with caffeine (C + C) solutions, or water (placebo; PLA) were rinsed for 10 seconds. During the remaining session, no solution was rinsed (control; CON). All solutions were flavored with (200 mg) sucralose. Felt arousal was recorded pre- and post-rinse, and rating of perceived exertion (RPE) was recorded immediately after the repetitions to failure. There were no significant differences in 1RM (p = 0.808; ηp(2)= 0.02), the number of repetitions performed (p = 0.682; ηp(2)= 0.03), or the total exercise volume (p = 0.482; ηp(2)= 0.03) between conditions. Rating of perceived exertion was similar for all trials (p = 0.330; ηp(2)= 0.08), whereas Felt arousal increased as a consequence of rinsing (p = 0.001; ηp(2)= 0.58), but was not different between trials (p = 0.335; ηp(2)= 0.08). These results suggest that rinsing with a CHO and CAF solution either independently or combined has no significant effect on maximum strength or muscular endurance performance.

Effects of 4-Week Training Intervention with Unknown Loads on Power Output Performance and Throwing Velocity in Junior Team Handball Players.

PubMed

Sabido, Rafael; Hernández-Davó, Jose Luis; Botella, Javier; Moya, Manuel

2016-01-01

To compare the effect of 4-week unknown vs known loads strength training intervention on power output performance and throwing velocity in junior team handball players. Twenty-eight junior team-handball players (17.2 ± 0.6 years, 1.79 ± 0.07 m, 75.6 ± 9.4 kg)were divided into two groups (unknown loads: UL; known loads: KL). Both groups performed two sessions weekly consisting of four sets of six repetitions of the bench press throw exercise, using the 30%, 50% and 70% of subjects' individual 1 repetition maximum (1RM). In each set, two repetitions with each load were performed, but the order of the loads was randomised. In the KL group, researchers told the subjects the load to mobilise prior each repetition, while in the UL group, researchers did not provide any information. Maximal dynamic strength (1RM bench press), power output (with 30, 50 and 70% of 1RM) and throwing velocity (7 m standing throw and 9 m jumping throw) were assessed pre- and post-training intervention. Both UL and KL group improved similarly their 1RM bench press as well as mean and peak power with all loads. There were significant improvements in power developed in all the early time intervals measured (150 ms) with the three loads (30, 50, 70% 1RM) in the UL group, while KL only improved with 30% 1RM (all the time intervals) and with 70% 1RM (at certain time intervals). Only the UL group improved throwing velocity in both standing (4.7%) and jumping (5.3%) throw (p > 0.05). The use of unknown loads has led to greater gains in power output in the early time intervals as well as to increases in throwing velocity compared with known loads. Therefore unknown loads are of significant practical use to increase both strength and in-field performance in a short period of training.

Crescent pyramid and drop-set systems do not promote greater strength gains, muscle hypertrophy, and changes on muscle architecture compared with traditional resistance training in well-trained men.

PubMed

Angleri, Vitor; Ugrinowitsch, Carlos; Libardi, Cleiton Augusto

2017-02-01

The aim of this study was to compare the effects of crescent pyramid (CP) and drop-set (DS) systems with traditional resistance training (TRAD) with equalized total training volume (TTV) on maximum dynamic strength (1-RM), muscle cross-sectional area (CSA), pennation angle (PA), and fascicle length (FL). Thirty-two volunteers had their legs randomized in a within-subject design in TRAD (3-5 sets of 6-12 repetitions at 75% 1-RM), CP (3-5 sets of 6-15 repetitions at 65-85% 1-RM), and DS (3-5 sets of ~50-75% 1-RM to muscle failure) protocols. Each leg was trained for 12 weeks. Participants had one leg fixed in the TRAD while the contralateral leg performed either CP or DS to allow for TTV equalization. The CSA increased significantly and similarly for all protocols (TRAD: 7.6%; CP: 7.5%; DS: 7.8%). All protocols showed significant and similar increases in leg press (TRAD = 25.9%; CP = 25.9%; DS = 24.9%) and leg extension 1-RM loads (TRAD = 16.6%; CP = 16.4%; DS = 17.1%). All protocols increased PA (TRAD = 10.6%; CP = 11.0%; DS = 10.3%) and FL (TRAD = 8.9%; CP = 8.9%; DS = 9.1%) similarly. CP and DS systems do not promote greater gains in strength, muscle hypertrophy and changes in muscle architecture compared to traditional resistance training.

The 1 Repetition Maximum Mechanics of a High-Handle Hexagonal Bar Deadlift Compared With a Conventional Deadlift as Measured by a Linear Position Transducer.

PubMed

Lockie, Robert G; Moreno, Matthew R; Lazar, Adrina; Risso, Fabrice G; Liu, Tricia M; Stage, Alyssa A; Birmingham-Babauta, Samantha A; Torne, Ibett A; Stokes, John J; Giuliano, Dominic V; Davis, DeShaun L; Orjalo, Ashley J; Callaghan, Samuel J

2018-01-01

Lockie, RG, Moreno, MR, Lazar, A, Risso, FG, Liu, TM, Stage, AA, Birmingham-Babauta, SA, Torne, IA, Stokes, JJ, Giuliano, DV, Davis, DL, Orjalo, AJ, and Callaghan, SJ. The 1 repetition maximum mechanics of a high-handle hexagonal bar deadlift compared with a conventional deadlift as measured by a linear position transducer. J Strength Cond Res 32(1): 150-161, 2018-The high-handle hexagonal bar deadlift (HHBD), a variation of the conventional deadlift (CD), is said to reduce the lift range of motion, which may change the mechanics of the lift. However, no research has investigated this. This study compared the mechanics between a 1 repetition maximum (1RM) CD and HHBD. Thirty-one strength-trained subjects (21 men, 10 women) completed a 1RM CD and HHBD. A linear position transducer measured lift distance, duration, and work; and peak and mean power, velocity, and force. The presence of a sticking region (SR) was determined for each lift. A repeated-measures analysis of variance (ANOVA) calculated differences between 1RM CD and HHBD mechanics. A one-way ANOVA compared the mechanics of each lift between subjects who exhibited an SR or not, and the SR between the CD and HHBD. Significance was set at p < 0.01. Subjects lifted a greater load in the HHBD (154.50 ± 45.29 kg) compared with the CD (134.72 ± 40.63 kg). Lift distance and duration were 22 and 25% shorter during the 1RM HHBD, respectively. The HHBD featured greater peak power and velocity, and peak and mean force; more work was done in the CD. Most subjects did not exhibit a CD (68%) or HHBD (77%) SR. There were no differences in CD or HHBD mechanics between subjects with or without an SR, and no differences in SR region distance or duration between the CD and HHBD. Greater force can be generated in the HHBD, which could have implications for strength-training adaptations over time.

Contextual interference effects on the acquisition of skill and strength of the bench press.

PubMed

Naimo, Marshall A; Zourdos, Michael C; Wilson, Jacob M; Kim, Jeong-Su; Ward, Emery G; Eccles, David W; Panton, Lynn B

2013-06-01

The purpose of this study was to investigate contextual interference effects on skill acquisition and strength gains during the learning of the bench press movement. Twenty-four healthy, college-aged males and females were stratified to control, high contextual interference (HCI), and low contextual interference (LCI) groups. Treatment groups were provided with written and visual instruction on proper bench press form and practiced the bench press and dart throwing for four weeks. Within each session, LCI performed all bench press sets before undertaking dart-throws. HCI undertook dart-throws immediately following each set of bench press. Control only did testing. Measurements, including one repetition maximum (1RM), checklist scores based on video recordings of participants' 1RM's, and dart-throw test scores were taken at pre-test, 1 week, 2 week, post-test, and retention test. Results were consistent with the basic premise of the contextual interference effect. LCI had significant improvements in percent 1RM and checklist scores during training, but were mostly absent after training (post-test and retention test). HCI had significant improvements in percent 1RM and checklist scores both during and after training. Thus, HCI may augment strength and movement skill on the bench press since proper technique is an important component of resistance exercise movements. Copyright © 2013 Elsevier B.V. All rights reserved.

The Effects of Low-Dose Creatine Supplementation Versus Creatine Loading in Collegiate Football Players

PubMed Central

Deivert, Richard G.; Hagerman, Frederick; Gilders, Roger

2001-01-01

Objective: To compare the effects of low doses of creatine and creatine loading on strength, urinary creatinine concentration, and percentage of body fat. Design and Setting: Division IA collegiate football players took creatine monohydrate for 10 weeks during a sport-specific, periodized, off-season strength and conditioning program. One-repetition maximum (1-RM) squat, urinary creatinine concentrations, and percentage of body fat were analyzed. Subjects: Twenty-five highly trained, Division IA collegiate football players with at least 1 year of college playing experience. Measurements: We tested strength with a 1-RM squat exercise before, during, and after creatine supplementation. Percentage of body fat was measured by hydrostatic weighing before and after supplementation. Urinary creatinine concentration was measured via light spectrophotometer at 0, 1, 3, 7, 14, 21, 28, 35, 42, 48, 56, and 63 days. An analysis of variance with repeated measures was computed to compare means for all variables. Results: Creatine supplementation had no significant group, time, or interaction effects on strength, urinary creatinine concentration, or percentage of body fat. However, significant time effects were found for 1-RM squat and fat-free mass in all groups. Conclusions: Our data suggest that creatine monohydrate in any amount does not have any beneficial ergogenic effects in highly trained collegiate football players. However, a proper resistance training stimulus for 10 weeks can increase strength and fat-free mass in highly trained athletes. PMID:12937451

An Estimate of the Size and Shape of Sunspot Cycle 24 Based on its Early Cycle Behavior using the Hathaway-Wilson-Reichmann Shape-Fitting Function

NASA Technical Reports Server (NTRS)

Wilson, Robert M.

2011-01-01

On the basis of 12-month moving averages (12-mma) of monthly mean sunspot number (R), sunspot cycle 24 had its minimum amplitude (Rm = 1.7) in December 2008. At 12 mo past minimum, R measured 8.3, and at 18 mo past minimum, it measured 16.4. Thus far, the maximum month-to-month rate of rise in 12-mma values of monthly mean sunspot number (AR(t) max) has been 1.7, having occurred at elapsed times past minimum amplitude (t) of 14 and 15 mo. Compared to other sunspot cycles of the modern era, cycle 24?s Rm and AR(t) max (as observed so far) are the smallest on record, suggesting that it likely will be a slow-rising, long-period sunspot cycle of below average maximum amplitude (RM). Supporting this view is the now observed relative strength of cycle 24?s geomagnetic minimum amplitude as measured using the 12-mma value of the aa-geomagnetic index (aam = 8.4), which also is the smallest on record, having occurred at t equals 8 and 9 mo. From the method of Ohl (the inferred preferential association between RM and aam), one predicts RM = 55 +/- 17 (the ?1 se prediction interval) for cycle 24. Furthermore, from the Waldmeier effect (the inferred preferential association between the ascent duration (ASC) and RM) one predicts an ASC longer than 48 mo for cycle 24; hence, maximum amplitude occurrence should be after December 2012. Application of the Hathaway-Wilson-Reichmann shape-fitting function, using an RM = 70 and ASC = 56 mo, is found to adequately fit the early sunspot number growth of cycle 24.

[Cost-consequence analysis of respiratory preventive intervention among institutionalized older people: randomized controlled trial].

PubMed

Cebrià I Iranzo, Maria Dels Àngels; Tortosa-Chuliá, M Ángeles; Igual-Camacho, Celedonia; Sancho, Patricia; Galiana, Laura; Tomás, José Manuel

2014-01-01

The institutionalized elderly with functional impairment show a greater decline in respiratory muscle (RM) function. The aims of the study are to evaluate outcomes and costs of RM training using Pranayama in institutionalized elderly people with functional impairment. A randomized controlled trial was conducted on institutionalized elderly people with walking limitation (n=54). The intervention consisted of 6 weeks of Pranayama RM training (5 times/week). The outcomes were measured at 4 time points, and were related to RM function: the maximum respiratory pressures and the maximum voluntary ventilation. Perceived satisfaction in the experimental group (EG) was assessed by means of an ad hoc questionnaire. Direct and indirect costs were estimated from the social perspective. The GE showed a significant improvement related with strength (maximum respiratory pressures) and endurance (maximum voluntary ventilation) of RM. Moreover, 92% of the EG reported a high satisfaction. The total social costs, direct and indirect, amounted to Euro 21,678. This evaluation reveals that RM function improvement is significant, that intervention is well tolerated and appreciated by patients, and the intervention costs are moderate. Copyright © 2013 SEGG. Published by Elsevier Espana. All rights reserved.

The effects of resistance training prioritization in NCAA Division I Football summer training.

PubMed

Smith, Robert A; Martin, Gerard J; Szivak, Tunde K; Comstock, Brett A; Dunn-Lewis, Courtenay; Hooper, David R; Flanagan, Shawn D; Looney, David P; Volek, Jeff S; Maresh, Carl M; Kraemer, William J

2014-01-01

Resistance training (RT) is an integral part of National Collegiate Athletic Association (NCAA) Division I Football performance programs. In the sport of football, there are several components that a strength and conditioning coach must be aware of. These include body mass, size, strength, power, speed, conditioning, and injury prevention, among others. The purpose of this study was to investigate if the RT component of a performance program could be prioritized for specific results using a nonlinear training model, grouping athletes by eligibility year. The NCAA Division I football student athletes were placed into 3 separate groups based on the playing year. All subjects participated in a 10-week, 4 days·week-1 off-season summer resistance training program. The training of group 1 (n = 20, age: 18.95 ± 0.76 years, height: 186.63 ± 7.21 cm, body mass: 97.66 ± 18.17 kg, playing year: 1.05 ± 0.22 years) prioritized hypertrophy-based RT to gain body mass. The training of group 2 (n = 20, age: 20.05 ± 1.05 years, height: 189.42 ± 5.49 cm, body mass: 106.99 ± 13.53 kg, and playing year: 2.35 ± 0.75 years) prioritized strength-based RT to gain strength. The training of group 3 (n = 20, age: 21.05 ± 1.10 years, height: 186.56 ± 6.73 cm, body mass: 109.8 ± 19.96 kg, playing year: 4.4 ± 0.50 years) prioritized power-based RT to gain power. Performance tests were evaluated during the first weeks of March (Spring) and August (Fall). The test measures included body mass (kilograms), 1-repetition maximum (1RM) bench press (kilograms), 1RM back squat (kilograms), 1RM power clean (kilograms), and countermovement vertical jump (CMVJ) height (centimeters). The primary findings of this investigation were as follows: group 1 saw significant increases in bench press maximum, back squat maximum, and power clean maximum (p ≤ 0.05). Group 2 saw significant increases in bench press maximum, back squat maximum, and power clean maximum (p ≤ 0.05). Group 3 saw a significant increase in power clean maximum (p ≤ 0.05). Group 1's significant increases were expected because of their low training age relatively shorter training history when compared with Groups 2 and 3. Group 1 did not see significant increases in body mass, with 7 out of 20 subjects being nonresponders. Group 2 and 3's significant increases were expected. Unexpectedly, no group saw significant increases in maximum CMVJ height. With so many factors that go into a football performance program contributing to football performance programing, it seems difficult to prioritize 1 RT goal over another without neglecting others during 10-week summer training program. Prioritization of strength appears to have the best overall affect on the RT portion of an off-season football performance program. Nonlinear periodization allows for the prioritization of 1 training goal without disregarding others with a smaller risk of neglecting other important components. This investigation showed that a performance program with a nonlinear model and prioritization on strength had produced the most desirable results.

Effects of β-alanine supplementation during a 5-week strength training program: a randomized, controlled study.

PubMed

Maté-Muñoz, José Luis; Lougedo, Juan H; Garnacho-Castaño, Manuel V; Veiga-Herreros, Pablo; Lozano-Estevan, María Del Carmen; García-Fernández, Pablo; de Jesús, Fernando; Guodemar-Pérez, Jesús; San Juan, Alejandro F; Domínguez, Raúl

2018-01-01

β-Alanine (BA) is a non-essential amino acid that has been shown to enhance exercise performance. The purpose of this investigation was to determine if BA supplementation improved the adaptive response to five weeks of a resistance training program. Thirty healthy, strength-trained individuals were randomly assigned to the experimental groups placebo (PLA) or BA. Over 5 weeks of strength training, subjects in BA took 6.4 g/day of BA as 8 × 800 mg doses each at least 1.5 h apart. The training program consisted of 3 sessions per week in which three different leg exercises were conducted as a circuit (back squat, barbell step ups and loaded jumping lunges). The program started with 3 sets of 40 s of work per exercise and rest periods between sets of 120 s in the first week. This training volume was then gradually built up to 5 sets of 20 s work/60 s rest in the fifth week. The work load during the program was set by one of the authors according to the individual's perceived effort the previous week. The variables measured were average velocity, peak velocity, average power, peak power, and load in kg in a back squat, incremental load, one-repetition maximum (1RM) test. In addition, during the rest period, jump ability (jump height and power) was assessed on a force platform. To compare data, a general linear model with repeated measures two-way analysis of variance was used. Significantly greater training improvements were observed in the BA group versus PLA group ( p  = 0.045) in the variables average power at 1RM (BA: 42.65%, 95% CI, 432.33, 522.52 VS. PLA: 21.07%, 95% CI, 384.77, 482.19) and average power at maximum power output ( p  = 0.037) (BA: 20.17%, 95% CI, 637.82, 751.90 VS. PLA; 10.74%, 95% CI, 628.31, 751.53). The pre- to post training average power gain produced at 1RM in BA could be explained by a greater maximal strength gain, or load lifted at 1RM ( p  = 0.014) (24 kg, 95% CI, 19.45, 28.41 VS. 16 kg, 95% CI, 10.58, 20.25) and in the number of sets executed ( p  = 0.025) in the incremental load test (BA: 2.79 sets, 95% CI, 2.08, 3.49 VS. PLA: 1.58 sets, 95% CI, 0.82, 2.34). β-Alanine supplementation was effective at increasing power output when lifting loads equivalent to the individual's maximal strength or when working at maximum power output. The improvement observed at 1RM was explained by a greater load lifted, or strength gain, in response to training in the participants who took this supplement.

The efficacy of incorporating partial squats in maximal strength training.

PubMed

Bazyler, Caleb D; Sato, Kimitake; Wassinger, Craig A; Lamont, Hugh S; Stone, Michael H

2014-11-01

The purpose of our study was to examine the effects of 2 different training methods on dynamic and isometric measures of maximal strength. Seventeen recreationally trained men (1 repetition maximum [1RM] squat: 146.9 ± 22.4 kg) were assigned to 2 groups: full range of motion (ROM) squat (F) and full ROM with partial ROM squat (FP) for the 7-week training intervention. Repeated measures analysis of variance revealed that there was a statistically significant group-by-time interaction for impulse scaled at 50, 90, and 250 milliseconds at 90° of knee flexion and rate of force development at 200 milliseconds with 120° of knee flexion (p ≤ 0.05). There was also a statistically significant time effect (p ≤ 0.05) for the 1RM squat, 1RM partial squat, isometric squat peak force allometrically scaled (IPFa) 90°, IPFa 120°, and impulse allometrically scaled at 50, 90, 200, and 250 milliseconds at 90° and 120° of knee flexion. Additionally, the FP group achieved statistically larger relative training intensities (%1RM) during the final 3 weeks of training (p ≤ 0.05). There was a trend for FP to improve over F in 1RM squat (+3.1%, d = 0.53 vs. 0.32), 1RM partial squat (+4.7%, d = 0.95 vs. 0.69), IPFa 120° (+5.7%, d = 0.52 vs. 0.12), and impulse scaled at 50, 90, 200, and 250 milliseconds at 90° (+6.3 to 13.2%, d = 0.50-1.01 vs. 0.30-0.57) and 120° (+3.4 to 16.8%, d = 0.45-1.11 vs. 0.08-0.37). These larger effect sizes in the FP group can likely be explained their ability to train at larger relative training intensities during the final 3 weeks of training resulting in superior training adaptations. Our findings suggest that partial ROM squats in conjunction with full ROM squats may be an effective training method for improving maximal strength and early force-time curve characteristics in men with previous strength training experience. Practically, partial squats may be beneficial for strength and power athletes during a strength-speed mesocycle while peaking for competition.

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.

Maximal strength and power assessment in novice weight trainers.

PubMed

Cronin, John B; Henderson, Melanie E

2004-02-01

The purpose of this study was to investigate whether changes in maximal strength and power output occurred over time in the absence of strength and power training in novice weight trainers. It also investigated whether differences existed between upper- and lower-body assessments and unilateral and bilateral assessments. The power output and maximal strength (1 repetition maximum [1RM]) of 10 male novice subjects were measured on 4 occasions, each assessment 7-10 days apart. The exercises used to measure the upper- and lower-body strength and power outputs were the bench press and supine squat, respectively. Significant (p < 0.05) changes in unilateral (9.8-16.8%) and bilateral 1RM (6.8-15.0%) leg strength were found, the first assessment being significantly different from all other assessments and assessment 2 significantly different from assessment 4. Changes in the upper body (10-13.6%) were also observed. The only significant difference was between assessment 1 and the other testing occasions. No differences in power output were observed for both the upper and lower body during the study. It would seem that considerable changes in maximal strength occur rapidly and in the absence of any formal strength training program in novice weight trainers.

Specific Changes in Young Soccer Player's Fitness After Traditional Bilateral vs. Unilateral Combined Strength and Plyometric Training

PubMed Central

Ramirez-Campillo, Rodrigo; Sanchez-Sanchez, Javier; Gonzalo-Skok, Oliver; Rodríguez-Fernandez, Alejandro; Carretero, Manuel; Nakamura, Fabio Y.

2018-01-01

The aim of this study was to compare changes in young soccer player's fitness after traditional bilateral vs. unilateral combined plyometric and strength training. Male athletes were randomly divided in two groups; both received the same training, including strength training for knee extensors and flexors, in addition to horizontal plyometric training drills. The only difference between groups was the mode of drills technique: unilateral (UG; n = 9; age, 17.3 ± 1.1 years) vs. bilateral (TG; n = 9; age, 17.6 ± 0.5 years). One repetition maximum bilateral strength of knee muscle extensors (1RM_KE) and flexors (1RM_KF), change of direction ability (COD), horizontal and vertical jump ability with one (unilateral) and two (bilateral) legs, and limb symmetry index were measured before and after an 8-week in-season intervention period. Some regular soccer drills were replaced by combination of plyometric and strength training drills. Magnitude-based inference statistics were used for between-group and within-group comparisons. Beneficial effects (p < 0.05) in 1RM_KE, COD, and several test of jumping performance were found in both groups in comparison to pre-test values. The limb symmetry index was not affected in either group. The beneficial changes in 1RM_KE (8.1%; p = 0.074) and 1RM_KF (6.7%; p = 0.004), COD (3.1%; p = 0.149), and bilateral jump performance (from 2.7% [p = 0.535] to 10.5% [p = 0.002]) were possible to most likely beneficial in the TG than in the UG. However, unilateral jump performance measures achieved likely to most likely beneficial changes in the UG compared to the TG (from 4.5% [p = 0.090] to 8.6% [p = 0.018]). The improvements in jumping ability were specific to the type of jump performed, with greater improvements in unilateral jump performance in the UG and bilateral jump performance in the TG. Therefore, bilateral strength and plyometric training should be complemented with unilateral drills, in order to maximize adaptations. PMID:29623049

Specific Changes in Young Soccer Player's Fitness After Traditional Bilateral vs. Unilateral Combined Strength and Plyometric Training.

PubMed

Ramirez-Campillo, Rodrigo; Sanchez-Sanchez, Javier; Gonzalo-Skok, Oliver; Rodríguez-Fernandez, Alejandro; Carretero, Manuel; Nakamura, Fabio Y

2018-01-01

The aim of this study was to compare changes in young soccer player's fitness after traditional bilateral vs. unilateral combined plyometric and strength training. Male athletes were randomly divided in two groups; both received the same training, including strength training for knee extensors and flexors, in addition to horizontal plyometric training drills. The only difference between groups was the mode of drills technique: unilateral (UG; n = 9; age, 17.3 ± 1.1 years) vs. bilateral (TG; n = 9; age, 17.6 ± 0.5 years). One repetition maximum bilateral strength of knee muscle extensors (1RM_KE) and flexors (1RM_KF), change of direction ability (COD), horizontal and vertical jump ability with one (unilateral) and two (bilateral) legs, and limb symmetry index were measured before and after an 8-week in-season intervention period. Some regular soccer drills were replaced by combination of plyometric and strength training drills. Magnitude-based inference statistics were used for between-group and within-group comparisons. Beneficial effects ( p < 0.05) in 1RM_KE, COD, and several test of jumping performance were found in both groups in comparison to pre-test values. The limb symmetry index was not affected in either group. The beneficial changes in 1RM_KE (8.1%; p = 0.074) and 1RM_KF (6.7%; p = 0.004), COD (3.1%; p = 0.149), and bilateral jump performance (from 2.7% [ p = 0.535] to 10.5% [ p = 0.002]) were possible to most likely beneficial in the TG than in the UG. However, unilateral jump performance measures achieved likely to most likely beneficial changes in the UG compared to the TG (from 4.5% [ p = 0.090] to 8.6% [ p = 0.018]). The improvements in jumping ability were specific to the type of jump performed, with greater improvements in unilateral jump performance in the UG and bilateral jump performance in the TG. Therefore, bilateral strength and plyometric training should be complemented with unilateral drills, in order to maximize adaptations.

Effect of the flexibility training performed immediately before resistance training on muscle hypertrophy, maximum strength and flexibility.

PubMed

Junior, Roberto Moriggi; Berton, Ricardo; de Souza, Thiago Mattos Frota; Chacon-Mikahil, Mara Patrícia Traina; Cavaglieri, Cláudia Regina

2017-04-01

It has been suggested that flexibility training may reduce the total volume of training during resistance trainings. The purpose of this study was to compare the effect of flexibility training immediately before resistance training (FLEX-RT) versus resistance training without flexibility training (RT) on maximum strength and the vastus lateralis muscle cross-sectional area (CSA). Participants had each leg assigned to RT or FLEX-RT. Both groups performed four sets of leg extensions to voluntary failure of 80% of one repetition maximum (1RM); however, FLEX-RT performed two sets of 25 s of static stretching before resistance training. Number of repetitions and total volume were calculated during weeks 1-5 and 6-10. Vastus lateralis muscle CSA, 1RM, and flexibility were assessed at baseline and after 10 weeks. The number of repetitions and total training volume were greater for RT than FLEX-RT for weeks 1-5 and 6-10. Regarding the vastus lateralis muscle CSA, a main time effect was observed, however, greater change was observed for RT than FLEX-RT (12.7 and 7.4%, respectively). A main time effect for 1RM was also observed with similar changes for RT and FLEX-RT (12.7 and 12.9%, respectively). Flexibility was increased pre- to post-training for FLEX-RT with greater change for FLEX-RT (10.1%) than RT (2.1%). These results show that performing flexibility training immediately before resistance training can contribute to a lower number of repetitions, total volume, and muscle hypertrophy.

The acute effects of a caffeine-containing supplement on bench press strength and time to running exhaustion.

PubMed

Beck, Travis W; Housh, Terry J; Malek, Moh H; Mielke, Michelle; Hendrix, Russell

2008-09-01

The purpose of the present study was to examine the acute effects of a caffeine-containing supplement (SUPP) on one-repetition maximum (1-RM) bench press strength and time to running exhaustion (TRE) at a velocity that corresponded to 85% of the peak oxygen uptake ([latin capital V with dot above]O2peak). The study used a double-blinded, placebo-controlled, crossover design. Thirty-one men (mean +/- SD age = 23.0 +/- 2.6 years) were randomly assigned to take either the SUPP or placebo (PLAC) first. The SUPP contained 201 mg of caffeine, and the PLAC was microcrystalline cellulose. All subjects were tested for 1-RM bench press strength and TRE at 45 minutes after taking either the SUPP or PLAC. After 1 week of rest, the subjects returned to the laboratory and ingested the opposite substance (SUPP or PLAC) from what was taken during the previous visit. The 1-RM bench press and TRE tests were then performed in the same manner as before. The results indicated that the SUPP had no effect on 1-RM bench press strength or TRE at 85% [latin capital V with dot above]O2peak. It is possible that the acute effects of caffeine are affected by differences in training status and/or the relative intensity of the exercise task. Future studies should examine these issues, in addition to testing the acute effects of various caffeine doses on performance during maximal strength, power, and aerobic activities. These findings do not, however, support the use of caffeine as an ergogenic aid in untrained to moderately trained individuals.

The effects of low-volume resistance training with and without advanced techniques in trained subjects.

PubMed

Gieβsing, Jùrgen; Fisher, James; Steele, James; Rothe, Frank; Raubold, Kristin; Eichmann, Björn

2016-03-01

This study examined low-volume resistance training (RT) in trained participants with and without advanced training methods. Trained participants (RT experience 4±3 years) were randomised to groups performing single-set RT: ssRM (N.=21) performing repetitions to self-determined repetition maximum (RM), ssMMF (N.=30) performing repetitions to momentary muscular failure (MMF), and ssRP (N.=28) performing repetitions to self-determined RM using a rest pause (RP) method. Each performed supervised RT twice/week for 10 weeks. Outcomes included maximal isometric strength and body composition using bioelectrical impedance analysis. The ssRM group did not significantly improve in any outcome. The ssMMF and ssRP groups both significantly improved strength (p < 0.05). Magnitude of changes using effect size (ES) was examined between groups. Strength ES's were considered large for ssMMF (0.91 to 1.57) and ranging small to large for ssRP (0.42 to 1.06). Body composition data revealed significant improvements (P<0.05) in muscle and fat mass and percentages for whole body, upper limbs and trunk for ssMMF, but only upper limbs for ssRP. Body composition ES's ranged moderate to large for ssMMF (0.56 to 1.27) and ranged small to moderate for ssRP (0.28 to 0.52). ssMMF also significantly improved (P<0.05) total abdominal fat and increased intracellular water with moderate ES's (-0.62 and 0.56, respectively). Training to self-determined RM is not efficacious for trained participants. Training to MMF produces greatest improvements in strength and body composition, however, RP style training does offer some benefit.

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

Knee Pain during Strength Training Shortly following Fast-Track Total Knee Arthroplasty: A Cross-Sectional Study

PubMed Central

Bandholm, Thomas; Thorborg, Kristian; Lunn, Troels Haxholdt; Kehlet, Henrik; Jakobsen, Thomas Linding

2014-01-01

Background Loading and contraction failure (muscular exhaustion) are strength training variables known to influence neural activation of the exercising muscle in healthy subjects, which may help reduce neural inhibition of the quadriceps muscle following total knee arthroplasty (TKA). It is unknown how these exercise variables influence knee pain after TKA. Objective To investigate the effect of loading and contraction failure on knee pain during strength training, shortly following TKA. Design Cross-sectional study. Setting Consecutive sample of patients from the Copenhagen area, Denmark, receiving a TKA, between November 2012 and April 2013. Participants Seventeen patients, no more than 3 weeks after their TKA. Main outcome measures: In a randomized order, the patients performed 1 set of 4 standardized knee extensions, using relative loads of 8, 14, and 20 repetition maximum (RM), and ended with 1 single set to contraction failure (14 RM load). The individual loadings (kilograms) were determined during a familiarization session >72 hours prior. The patients rated their knee pain during each repetition, using a numerical rating scale (0–10). Results Two patients were lost to follow up. Knee pain increased with increasing load (20 RM: 3.1±2.0 points, 14 RM: 3.5±1.8 points, 8 RM: 4.3±2.5 points, P = 0.006), and repetitions to contraction failure (10% failure: 3.2±1.9 points, 100% failure: 5.4±1.6 points, P<0.001). Resting knee pain 60 seconds after the final repetition (2.7±2.4 points) was not different from that recorded before strength training (2.7±1.8 points, P = 0.88). Conclusion Both loading and repetitions performed to contraction failure during knee- extension strength-training, increased post-operative knee pain during strength training implemented shortly following TKA. However, only the increase in pain during repetitions to contraction failure exceeded that defined as clinically relevant, and was very short-lived. Trial Registration ClinicalTrials.gov NCT01729520 PMID:24614574

Effect of compensatory acceleration training in combination with accommodating resistance on upper body strength in collegiate athletes

PubMed Central

Jones, Margaret T

2014-01-01

Purpose To determine the impact of inclusion of a band or chain compensatory acceleration training (CAT), in a 5-week training phase, on maximal upper body strength during a 14-week off-season strength and conditioning program for collegiate male athletes. Patients and methods Twenty-four National Collegiate Athletic Association (NCAA) collegiate baseball players, who were familiar with the current strength and conditioning program and had a minimum of 1 year of formal collegiate strength and conditioning experience, participated in this off-season training study. None of the men had participated in CAT before. Subjects were matched following a maximal effort (1-repetition maximum [1-RM]) bench press test in week 1, then were randomly assigned into a band-based CAT group or a chain-based CAT group and participated in a 5-week training phase that included bench pressing twice per week. Upper body strength was measured by 1-RM bench press again at week 6. A 2 × 2 mixed factorial (method × time) analysis of variance was calculated to compare differences across groups. The alpha level was set at P<0.05. Results No difference (F1,22=0.04, P=0.84) existed between the band-based CAT and chain-based CAT groups. A significant difference was observed between pre- and posttests of 1-RM bench (F1,22=88.46, P=0.001). Conclusion A 5-week band CAT or chain CAT training program used in conjunction with an off-season strength and conditioning program can increase maximal upper body strength in collegiate baseball athletes. Using band CAT and/or chain CAT as a training modality in the off-season will vary the training stimulus from the traditional and likely help to maintain the athlete’s interest. PMID:25177154

Predicting maximal strength in trained postmenopausal woman.

PubMed

Kemmler, Wolfgang K; Lauber, Dirk; Wassermann, Alfred; Mayhew, Jerry L

2006-11-01

The purpose of this study was to present an equation that accurately predicts 1 repetition maximum (RM) over a wide range of repetitions to fatigue (RTF) for 4 different machine resistance exercises in postmenopausal women. Seventy trained women (age = 57.4 +/- 3.1 years) performed maximal and submaximal repetitions on leg press, bench press, rowing, and leg adduction machines at the conclusion of a 2-year training program. Maximal repetitions were performed on each exercise in the following ranges: 3-5RM, 6-10RM, 11-15RM, and 16-20RM. Special regard was taken to maintain the identical execution of each test (i.e., range of motion, starting angle, speed of movement). One cubic polynomial (w(i) [0.988-0.0000584 r(i)(3) + 0.00190 r(i)(2) + 0.0104 r(i),] where w(i) is the load of measurement I, and r(i) is the number of repetitions) accurately predicted 1RM from RTF with mean absolute differences between actual 1RM and predicted 1RM for the 4 exercises of 1.5-3.1% and with coefficients of variation of <3.3%. Equation accuracy was independent of the exercise type or the number of RTF. Thus, this study supported the validity of RTF to adequately estimate 1RM over a wide range of repetitions and within different exercises in trained, older female subjects.

Comparison of muscle force production using the Smith machine and free weights for bench press and squat exercises.

PubMed

Cotterman, Michael L; Darby, Lynn A; Skelly, William A

2005-02-01

The Smith machine (SM) (vertical motion of bar on fixed path; fixed-form exercise) and free weights (FWs) (free-form path) are commonly used strength training modes. Exercisers may need to alternate between types of equipment, depending on testing, training, rehabilitation, and/or the exercisers' goals. The purposes of this study were to compare muscle force production for SM and FWs using a 1 repetition maximum (1RM) for the parallel back squat and supine bench press exercises and to predict the 1RM for one mode from 1RM on the other mode. Men (n = 16) and women (n = 16) alternately completed 1RM testing for squat and bench press using SM and FWs. Analyses of variance (type of equipment x sex) and linear regression models were calculated. A significant difference was found between bench press and squat 1RMs for each mode of equipment for all participants. The squat 1RM was greater for the SM than the FWs; conversely, the bench 1RM was greater for FWs than the SM. When sex was considered, bench 1RM for FWs was greater than SM for men and women. The squat 1RM was greater for SM than FWs for women only. The 1RM on one mode of equipment was the best predictor of 1RM for the other mode. For both sexes, the equation SM bench 1RM (in kilograms) = -6.76 + 0.95 (FW bench 1RM) can be used. For women only, SM squat 1RM (in kilograms) = 28.3 + 0.73 (FW squat 1RM). These findings provide equations for converting between SM and FW equipment for training.

Effect of rest-pause vs. traditional bench press training on muscle strength, electromyography, and lifting volume in randomized trial protocols.

PubMed

Korak, J Adam; Paquette, Max R; Brooks, Justin; Fuller, Dana K; Coons, John M

2017-09-01

Rest-pause (4-s unloaded rest between repetitions) training effects on one repetition maximum (1 RM), lifting volume, and neural activation via electromyography (EMG) are currently vague in the literature and can benefit strength and conditioning professionals for resistance training programme design. Therefore, this study compared 1 RM, neural activation via (EMG), and volume differences between rest-pause vs. traditional resistance training. Trained males (N = 20) were randomly assigned to either a rest-pause or a traditional training group. Pre- and post-1 RM testing was recorded. Training sessions were completed twice a week for 4 weeks and consisted of four sets of bench press to volitional fatigue at 80% of pre-test 1 RM with a 2-min rest between sets. Total volume completed was recorded on each training day. Neural activation of the pectoralis major was measured on the first and last training days. A two-way repeated-measures ANOVA indicated both groups significantly increased their 1 RMs following the 4-week training protocol (p < .05). However, no significant differences were found in 1 RM and neural activation between the two groups (p > .05). An independent samples t test indicated that total volume lifted was significantly higher for the rest-pause group (56,778 vs. 38,315 lbs; p < .05) throughout the protocol and independently during weeks 2, 3, and 4. While strength and neural activation changes did not differ between groups, both increased 1 RMs and the rest-pause group achieved greater increases in volume than the traditional group. If volume is the focus of training, the rest-pause method should be utilized.

EFFECTS OF WHOLE BODY VIBRATION ON STRENGTH AND JUMPING PERFORMANCE IN VOLLEYBALL AND BEACH VOLLEYBALL PLAYERS

PubMed Central

Zmijewski, P.; Jimenez-Olmedo, J.M.; Jové-Tossi, M.A.; Martínez-Carbonell, A.; Suárez-Llorca, C.; Andreu-Cabrera, E.

2014-01-01

The primary aim of this study was to examine the effects of 6-week strength training with whole body vibration (WBV) on leg strength and jumping performance in volleyball and beach volleyball players. Twenty-three sub-elite male volleyball (VB; n=12) and beach volleyball players (BVB; n=11) aged 21.2±3.0 years were divided into two groups and subjected to 6 weeks of strength training (three one-hour sessions per week): (I) 12 players (6 VB and 6 BVB players) underwent training with WBV (30-40 Hz, 1.7-2.5 mm, 3.0-5.7 g), and (II) 11 players (6 VB and 5 BVB players) underwent traditional strength training. Squat jump (SJ) and countermovement squat jump (CMJ) measurements by the Ergo Tester contact platform and maximum leg press test (1RM) were conducted. Three-factor (2 time x 2 WBV use x 2 discipline) analysis of variance for SJ, CMJ and 1RM revealed a significant time main effect (p<0.001), a WBV use effect (p<0.001) and a discipline effect (p<0.001). Significantly greater improvements in the SJ (p<0.001) and CMJ (p<0.001) and in 1RM (p<0.001) were found in the WBV training groups than in traditional training groups. Significant 3-way interaction effects (training, WBV use, discipline kind) were also found for SJ, CMJ and 1RM (p=0.001, p<0.001, p=0.001, respectively). It can be concluded that implementation of 6-week WBV training in routine practice in volleyball and beach volleyball players increases leg strength more and leads to greater improvement in jump performance than traditional strength training, but greater improvements can be expected in beach volleyball players than in volleyball players. PMID:25187676

Effect of Combined Sensorimotor-Resistance Training on Strength, Balance, and Jumping Performance of Soccer Players.

PubMed

Manolopoulos, Konstantinos; Gissis, Ioannis; Galazoulas, Christos; Manolopoulos, Evaggelos; Patikas, Dimitrios; Gollhofer, Albert; Kotzamanidis, Christos

2016-01-01

The purpose of the study was to investigate the effects of resistance training (RT) and sensorimotor training combined with RT (SM-RT) on balance, 1 repetition maximum (RM), rate of force development (RFD), and squat jump (SJ) height. Twenty amateur soccer players were equally divided into 2 groups assigned as SM-RT group (age: 22 ± 1.7 years, body mass: 79.9 ± 6.3 kg, body height: 1.81 ± 0.06 m) and RT group (age: 21.3 ± 1.3 years, body mass: 77.4 ± 9.3 kg, body height: 1.78 ± 0.04 m). Both groups were trained over a 6-week period with 2 session units per week. SM-RT group performed sensorimotor training (balance on balance board) followed by a high-intensity RT at 8-5RM leg press. The RT group performed the resistance program only. Both groups showed significantly increased 1RM leg press strength, RFD, SJ height, and balance abilities (p ≤ 0.05), whereas no significant between-group differences were observed in any of the outcome variables (p > 0.05). It was concluded that SM-RT was not superior compared with RT for both balance and strength enhancement. These findings have implications in time management during training for soccer players.

Weaker lower extremity muscle strength predicts traumatic knee injury in youth female but not male athletes.

PubMed

Ryman Augustsson, Sofia; Ageberg, Eva

2017-01-01

The role of lower extremity (LE) muscle strength for predicting traumatic knee injury in youth athletes is largely unknown. The aim was to investigate the influence of LE muscle strength on traumatic knee injury in youth female and male athletes. 225 athletes (40% females) from sport senior high schools in Sweden were included in this case-control study. The athletes recorded any traumatic knee injury that had occurred during their high-school period in a web-based injury form. A one repetition maximum (1RM) barbell squat test was used to measure LE muscle strength. The 1RM was dichotomised to analyse 'weak' versus 'strong' athletes according to the median (weak median vs strong median ). 63 traumatic knee injuries, including 18 ACL injuries, were registered. The majority of injured female athletes were in the weak group compared with the strong group (p=0.0001). The odds of sustaining a traumatic knee injury and an ACL injury was 9.5 times higher and 7 times higher, respectively, in the weak median group compared with the strong median group in females (p ≤0.011). A relative 1RM squat ≤1.05 kg (105% of bodyweight) was established as the best cut-off value to distinguish high versus low risk of injury in female athletes. No strength-injury relationships were observed for the male athletes (p ≥0.348). Weaker LE muscle strength predicted traumatic knee injury in youth female athletes, but not in males. This suggests that LE muscle strength should be included in injury screening in youth female athletes.

The Neuromuscular Qualities of Higher- and Lower-Level Mixed-Martial-Arts Competitors.

PubMed

James, Lachlan P; Beckman, Emma M; Kelly, Vincent G; Haff, G Gregory

2017-05-01

To determine whether the maximal strength, impulse, and power characteristics of competitive mixed-martial-arts (MMA) athletes differ according to competition level. Twenty-nine male semiprofessional and amateur MMA competitors were stratified into either higher-level (HL) or lower-level (LL) performers on the basis of competition grade and success. The 1-repetition-maximum (1RM) squat was used to assess lower-body dynamic strength, and a spectrum of impulse, power, force, and velocity variables were evaluated during an incremental-load jump squat. In addition, participants performed an isometric midthigh pull (IMTP) and 1RM bench press to determine whole-body isometric force and upper-body dynamic strength capabilities, respectively. All force and power variables were expressed relative to body mass (BM). The HL competitors produced significantly superior values across a multitude of measures. These included 1RM squat strength (1.84 ± 0.23 vs 1.56 ± 0.24 kg BM; P = .003), in addition to performance in the incremental-load jump squat that revealed greater peak power (P = .005-.002), force (P = .002-.004), and velocity (P = .002-.03) at each load. Higher measures of impulse (P = .01-.04) were noted in a number of conditions. Average power (P = .002-.02) and velocity (P = .01-.04) at all loads in addition to a series of rate-dependent measures were also superior in the HL group (P = .005-.02). The HL competitors' 1RM bench-press values approached significantly greater levels (P = .056) than the LL group's, but IMTP performance did not differ between groups. Maximal lower-body neuromuscular capabilities are key attributes distinguishing HL from LL MMA competitors. This information can be used to inform evidenced-based training and performance-monitoring practices.

Electromyographic activity and 6RM strength in bench press on stable and unstable surfaces.

PubMed

Saeterbakken, Atle H; Fimland, Marius S

2013-04-01

The purpose of the study was to compare 6-repetition maximum (6RM) loads and muscle activity in bench press on 3 surfaces, namely, stable bench, balance cushion, and Swiss ball. Sixteen healthy, resistance-trained men (age 22.5 ± 2.0 years, stature 1.82 ± 6.6 m, and body mass 82.0 ± 7.8 kg) volunteered for 3 habituation/strength testing sessions and 1 experimental session. In randomized order on the 3 surfaces, 6RM strength and electromyographic activity of pectoralis major, deltoid anterior, biceps brachii, triceps brachii, rectus abdominis, oblique external and erector spinae were assessed. Relative to stable bench, the 6RM strength was approximately 93% for balance cushion (p ≤ 0.001) and approximately 92% for Swiss ball (p = 0.008); the pectoralis major electromyographic (EMG) activity was approximately 90% using the balance cushion (p = 0.080) and approximately 81% using Swiss ball (p = 0.006); the triceps EMG was approximately 79% using the balance cushion (p = 0.028) and approximately 69% using the Swiss ball (p = 0.002). Relative to balance cushion, the EMG activity in pectoralis, triceps, and erector spinae using Swiss ball was approximately 89% (p = 0.016), approximately 88% (p = 0.014) and approximately 80% (p = 0.020), respectively. In rectus abdominis, the EMG activity relative to Swiss ball was approximately 69% using stable bench (p = 0.042) and approximately 65% using the balance cushion (p = 0.046). Similar EMG activities between stable and unstable surfaces were observed for deltoid anterior, biceps brachii, and oblique external. In conclusion, stable bench press had greater 6RM strength and triceps and pectoralis EMG activity compared with the unstable surfaces. These findings have implications for athletic training and rehabilitation, because they demonstrate an inferior effect of unstable surfaces on muscle activation of prime movers and strength in bench press. If an unstable surface in bench press is desirable, a balance cushion should be chosen instead of a Swiss ball.

Moderate Intensity Cycling Exercise after Upper Extremity Resistance Training Interferes Response to Muscle Hypertrophy but Not Strength Gains

PubMed Central

Tomiya, Shigeto; Kikuchi, Naoki; Nakazato, Koichi

2017-01-01

The purpose of the present study was to examine the effect of 30-min moderate intensity cycling exercise immediately after upper-body resistance training on the muscle hypertrophy and strength gain. Fourteen subjects were randomly divided between two groups. One group performed moderate intensity (55% of maximum oxygen consumption [VO2max], 30 min) cycle training immediately after arm resistance training as concurrent training (CT; n = 7, age: 21.8 ± 0.7 years, height: 1.68 ± 0.06 m, weight: 60.3 ± 7.4 kg); the second group performed the same endurance and arm RT on separate days as control group (SEP; n=7, age: 22.1 ± 0.7 years, height: 1.76 ± 0.05 m, weight: 63.8 ± 3.6 kg). The supervised progressive RT program was designed to induce muscular hypertrophy (3-5 sets of 10 repetitions) with bilateral arm-curl exercise using 75% of the one repetition maximum (1RM) with 2-min rest intervals. The RT program was performed for 8 weeks, twice per week. Muscle cross-sectional area (CSA), 1RM, and VO2max were measured pre- and post-training. Significant increases in muscle CSA from pre- to post-training were observed in both the SEP (p = 0.001, effect size [ES] = 0.84) and the CT groups (p = 0.004, ES = 0.45). A significant increase in 1RM from pre- to post-training was observed in the SEP (p = 0.025, ES = 0.91) and CT groups (p = 0.001, ES = 2.38). There were no interaction effects (time × group) for CSA, 1RM, or VO2max. A significantly higher percentage change of CSA was observed in the SEP group (12.1 ± 4.9%) compared to the CT group (5.0 ± 2.7%, p = 0.029), but no significant difference was observed in the 1RM (SEP: 19.8 ± 16.8%, CT: 24.3 ± 11.1%). The data suggest that significant improvement of CSA and strength can be expected with progressive resistance training with subsequent endurance exercise performed immediately or on a different day. Changes in CSA might be affected by subsequent cycling exercise after 8 weeks of training. Key points Moderate intensity cycling exercise immediately after upper-body resistance training influences the magnitude of muscle hypertrophy and relative value of CSA changes. There was no statistically significant difference in the % change in 1RM between groups after concurrent strength training and moderate intensity endurance training. Timing of endurance training could alter the degree of muscular growth induced by resistance training. PMID:28912657

Effect of Different Interrepetition Rest Periods on Barbell Velocity Loss During the Ballistic Bench Press Exercise.

PubMed

García-Ramos, Amador; Padial, Paulino; Haff, G Gregory; Argüelles-Cienfuegos, Javier; García-Ramos, Miguel; Conde-Pipó, Javier; Feriche, Belén

2015-09-01

This study investigated the effect of introducing different interrepetition rest (IRR) periods on the ability to sustain maximum bench press throw velocity with a range of loads commonly used to develop upper-body power. Thirty-four physically active collegiate men (age: 21.5 ± 2.8 years; body mass: 75.2 ± 7.2 kg; height: 176.9 ± 4.9 cm) were tested during 2 consecutive weeks. During the first week, the maximum dynamic strength (repetition maximum [RM]) in bench press exercise was determined (RM = 76.7 ± 13.2 kg). The following week, 3 testing sessions were conducted with 48 hours apart in random order. In each day of evaluation, only 1 load (30%RM, 40%RM, or 50%RM) was assessed in the bench press throw exercise. With each load, subjects performed 3 single sets of 15 repetitions (15-minute interset rest) with 3 different sets configurations: continuous repetitions (CR), 6 seconds of IRR (IRR6), and 12 seconds of IRR (IRR12). The decrease of peak velocity (PV) was significantly lower for IRR12 compared with CR and IRR6 at least since the repetition 4. No differences between CR and IRR6 protocols were found until the repetition 7 at 30%RM and 40%RM and until the repetition 5 at 50%RM. The decrease of PV during the CR protocol was virtually linear for the 3 loads analyzed (r > 0.99); however, this linear relationship became weaker for IRR6 (r = 0.79-0.95) and IRR12 (r = 0.35-0.87). These results demonstrate that IRR periods allow increasing the number of repetitions before the onset of significant velocity losses.

Analysis of postural control and muscular performance in young and elderly women in different age groups.

PubMed

Gomes, Matheus M; Reis, Júlia G; Carvalho, Regiane L; Tanaka, Erika H; Hyppolito, Miguel A; Abreu, Daniela C C

2015-01-01

muscle strength and power are two factors affecting balance. The impact of muscle strength and power on postural control has not been fully explored among different age strata over sixty. the aim of the present study was to assess the muscle strength and power of elderly women in different age groups and determine their correlation with postural control. eighty women were divided into four groups: the young 18-30 age group (n=20); the 60-64 age group (n=20); the 65-69 age group (n=20); and the 70-74 age group (n=20). The participants underwent maximum strength (one repetition maximum or 1-RM) and muscle power tests to assess the knee extensor and flexor muscles at 40%, 70%, and 90% 1-RM intensity. The time required by participants to recover their balance after disturbing their base of support was also assessed. the elderly women in the 60-64, 65-69, and 70-74 age groups exhibited similar muscle strength, power, and postural control (p>0.05); however, these values were lower than those of the young group (p<0.05) as expected. There was a correlation between muscle strength and power and the postural control performance (p<0.05). despite the age difference, elderly women aged 60 to 74 years exhibited similar abilities to generate strength and power with their lower limbs, and this ability could be one factor that explains the similar postural control shown by these women.

Effects of 4-Week Training Intervention with Unknown Loads on Power Output Performance and Throwing Velocity in Junior Team Handball Players

PubMed Central

Sabido, Rafael; Hernández-Davó, Jose Luis; Botella, Javier; Moya, Manuel

2016-01-01

Purpose To compare the effect of 4-week unknown vs known loads strength training intervention on power output performance and throwing velocity in junior team handball players. Methods Twenty-eight junior team-handball players (17.2 ± 0.6 years, 1.79 ± 0.07 m, 75.6 ± 9.4 kg)were divided into two groups (unknown loads: UL; known loads: KL). Both groups performed two sessions weekly consisting of four sets of six repetitions of the bench press throw exercise, using the 30%, 50% and 70% of subjects’ individual 1 repetition maximum (1RM). In each set, two repetitions with each load were performed, but the order of the loads was randomised. In the KL group, researchers told the subjects the load to mobilise prior each repetition, while in the UL group, researchers did not provide any information. Maximal dynamic strength (1RM bench press), power output (with 30, 50 and 70% of 1RM) and throwing velocity (7 m standing throw and 9 m jumping throw) were assessed pre- and post-training intervention. Results Both UL and KL group improved similarly their 1RM bench press as well as mean and peak power with all loads. There were significant improvements in power developed in all the early time intervals measured (150 ms) with the three loads (30, 50, 70% 1RM) in the UL group, while KL only improved with 30% 1RM (all the time intervals) and with 70% 1RM (at certain time intervals). Only the UL group improved throwing velocity in both standing (4.7%) and jumping (5.3%) throw (p > 0.05). Conclusions The use of unknown loads has led to greater gains in power output in the early time intervals as well as to increases in throwing velocity compared with known loads. Therefore unknown loads are of significant practical use to increase both strength and in-field performance in a short period of training. PMID:27310598

Effects of different volume-equated resistance training loading strategies on muscular adaptations in well-trained men.

PubMed

Schoenfeld, Brad J; Ratamess, Nicholas A; Peterson, Mark D; Contreras, Bret; Sonmez, G T; Alvar, Brent A

2014-10-01

Regimented resistance training has been shown to promote marked increases in skeletal muscle mass. Although muscle hypertrophy can be attained through a wide range of resistance training programs, the principle of specificity, which states that adaptations are specific to the nature of the applied stimulus, dictates that some programs will promote greater hypertrophy than others. Research is lacking, however, as to the best combination of variables required to maximize hypertophic gains. The purpose of this study was to investigate muscular adaptations to a volume-equated bodybuilding-type training program vs. a powerlifting-type routine in well-trained subjects. Seventeen young men were randomly assigned to either a hypertrophy-type resistance training group that performed 3 sets of 10 repetition maximum (RM) with 90 seconds rest or a strength-type resistance training (ST) group that performed 7 sets of 3RM with a 3-minute rest interval. After 8 weeks, no significant differences were noted in muscle thickness of the biceps brachii. Significant strength differences were found in favor of ST for the 1RM bench press, and a trend was found for greater increases in the 1RM squat. In conclusion, this study showed that both bodybuilding- and powerlifting-type training promote similar increases in muscular size, but powerlifting-type training is superior for enhancing maximal strength.

Variable Resistance Training Promotes Greater Strength and Power Adaptations Than Traditional Resistance Training in Elite Youth Rugby League Players.

PubMed

Rivière, Maxence; Louit, Loic; Strokosch, Alasdair; Seitz, Laurent B

2017-04-01

Rivière, M, Louit, L, Strokosch, A, and Seitz, LB. Variable resistance training promotes greater strength and power adaptations than traditional resistance training in elite youth rugby league players. J Strength Cond Res 31(4): 947-955, 2017-The purpose of this study was to examine the strength, velocity, and power adaptations in youth rugby league players in response to a variable resistance training (VRT) or traditional free-weight resistance training (TRAD) intervention. Sixteen elite youth players were assigned to a VRT or TRAD group and completed 2 weekly upper- and lower-body strength and power sessions for 6 weeks. Training programs were identical except that the VRT group trained the bench press exercise with 20% of the prescribed load coming from elastic bands. Bench press 1 repetition maximum (1RM) and bench press mean velocity and power at 35, 45, 65, 75, and 85% of 1RM were measured before and after the training intervention, and the magnitude of the changes was determined using effect sizes (ESs). The VRT group experienced larger increases in both absolute (ES = 0.46 vs. 0.20) and relative (ES = 0.41 vs. 0.19) bench press 1RM. Similar results were observed for mean velocity as well as both absolute and relative mean power at 35, 45, 65, 75, and 85% of 1RM. Furthermore, both groups experienced large gains in both velocity and power in the heavier loads but small improvements in the lighter loads. The improvements in both velocity and power against the heavier loads were larger for the VRT group, whereas smaller differences existed between the 2 groups in the lighter loads. Variable resistance training using elastic bands may offer a greater training stimulus than traditional free-weight resistance training to improve upper-body strength, velocity, and power in elite youth rugby league players.

Strength and Conditioning Training by the Danish National Handball Team Before an Olympic Tournament.

PubMed

Kvorning, Thue; Hansen, Mikkel R B; Jensen, Kurt

2017-07-01

Kvorning, T, Hansen, MRB, and Jensen, K. Strength and conditioning training by the Danish national handball team before an Olympic tournament. J Strength Cond Res 31(7): 1759-1765, 2017-The physical demands imposed on national team handball teams during the Olympics imply significant physical preparation to improve performance and reduce incidence of injuries. The purpose of this case report was to describe and analyze the strength and conditioning (S&C) training performed by the Danish national handball team before the Beijing Olympic Games. Eight weeks of S&C was divided into 5 weeks emphasizing muscle hypertrophy and long-interval running followed by 3 weeks emphasizing strength, power, and short-interval running. Body mass increased by 1.6% (p < 0.05), whereas body fat decreased by 1.0% (p < 0.05). No differences were seen in countermovement jump or jump-and-reach height (p > 0.05). Agility performance was evaluated by a T-test and improved by 2.5% (p < 0.05). Changes by 6% and 22% were seen in 1 repetition maximum (1RM) bench press and 1RM back squat, respectively. However, only the 1RM bench press increased significantly (p < 0.05). Running performance was tested by the Yo-Yo intermittent recovery test, level 2, and improved by 25% (p < 0.05). In conclusion, during 8 weeks of S&C training before the Beijing Olympics, body composition changed toward more muscle mass, better upper-body strength, better interval running, and agility performance, whereas no changes were seen in jumping or lower-body muscle strength. This case report may be used as a handy script for handball teams preparing for competition. Detailed and periodized S&C training programs for 8 weeks are provided and can be used by teams ranging from moderately to highly trained.

Do PTK2 gene polymorphisms contribute to the interindividual variability in muscle strength and the response to resistance training? A preliminary report.

PubMed

Erskine, Robert M; Williams, Alun G; Jones, David A; Stewart, Claire E; Degens, Hans

2012-04-01

The protein tyrosine kinase-2 (PTK2) gene encodes focal adhesion kinase, a structural protein involved in lateral transmission of muscle fiber force. We investigated whether single-nucleotide polymorphisms (SNPs) of the PTK2 gene were associated with various indexes of human skeletal muscle strength and the interindividual variability in the strength responses to resistance training. We determined unilateral knee extension single repetition maximum (1-RM), maximum isometric voluntary contraction (MVC) knee joint torque, and quadriceps femoris muscle specific force (maximum force per unit physiological cross-sectional area) before and after 9 wk of knee extension resistance training in 51 untrained young men. All participants were genotyped for the PTK2 intronic rs7843014 A/C and 3'-untranslated region (UTR) rs7460 A/T SNPs. There were no genotype associations with baseline measures or posttraining changes in 1-RM or MVC. Although the training-induced increase in specific force was similar for all PTK2 genotypes, baseline specific force was higher in PTK2 rs7843014 AA and rs7460 TT homozygotes than in the respective rs7843014 C- (P = 0.016) and rs7460 A-allele (P = 0.009) carriers. These associations between muscle specific force and PTK2 SNPs suggest that interindividual differences exist in the way force is transmitted from the muscle fibers to the tendon. Therefore, our results demonstrate for the first time the impact of genetic variation on the intrinsic strength of human skeletal muscle.

Acute muscular strength assessment using free weight bars of different thickness.

PubMed

Ratamess, Nicholas A; Faigenbaum, Avery D; Mangine, Gerald T; Hoffman, Jay R; Kang, Jie

2007-02-01

The purpose of the present investigation was to examine strength performance of 6 common resistance training exercises using free weight bars of different thickness. Eleven resistance-trained men (8.2 +/- 2.6 years of experience; age: 22.1 +/- 1.6 years; body mass: 90.5 +/- 8.9 kg) underwent 1 repetition maximum (1RM) strength testing on 6 occasions in random order for the deadlift, bent-over row, upright row, bench press, seated shoulder press, and arm curl exercises under 3 conditions using: (a) a standard Olympic bar (OL), (b) a 2-inch thick bar (5.08 cm grip span), and (c) a 3-inch thick bar (7.62 cm grip span). Significant (p < 0.05) interactions were observed for the "pulling" exercises. For the deadlift and bent-over row, highest 1RM values were obtained with OL, followed by the 2- and 3-inch bar. Significant 1RM performance decrements for the 2- and 3-inch bars were approximately 28.3 and 55.0%, respectively, for the deadlift; decrements for the 2- and 3-inch bars were approximately 8.9 and 37.3%, respectively, for the bent-over row. For the upright row and arm curl, similar 1RMs were obtained for OL and the 2-inch bar. However, a significant performance reduction was observed using the 3-inch bar (approximately 26.1% for the upright row and 17.6% for the arm curl). The reductions in 1RM loads correlated significantly to hand size and maximal isometric grip strength (r = -0.55 to -0.73). No differences were observed between bars for the bench press or shoulder press. In conclusion, the use of 2- and 3-inch thick bars may result in initial weight reductions primarily for pulling exercises presumably due to greater reliance on maximal grip strength and larger hand size.

Multivisceral Transplantation Rehabilitation Program-Case Report.

PubMed

Loschi, T M; Cinacchi, M P R G; Baccan, M D T A; Marques, F; Pedroso, P T; Meira Filho, S P; Scacchetti, T; Pavão, D N

2018-04-01

Multivisceral transplantation is the treatment for multiple abdominal organ failure. The patient experiences reduced food intake and absorption of nutrients, contributing to weight loss and decreased muscle mass, reducing functional capacity. A physical and nutritional rehabilitation program based on adequate caloric intake associated with supervised physical exercise seems to support a gain of muscle mass, re-establishing its capacity and functional independence. A rehabilitation program was carried out, consisting of low-intensity aerobic exercise on treadmill, exercises of global strengthening (50% of 1 maximum repetition [1RM], with progressive increase), and nutritional monitoring (oral hypercaloric diet, hyperproteic supplementation daily and after exercise). Initial and final evaluation included weight, muscle mass index, brachial circumference (BC), tricipital cutaneous fold (TCF), hand grip strength (HGS), 6-minute walk test (6MWT), 1RM, vital capacity (VC), and respiratory muscle strength. After the program, functional capacity was evaluated through the 6MWT (92%), 1RM test, VC (55%), respiratory muscle strength, HGS at 5 kg, weight gain (4.75%), increase of BC in 2 cm, and TCF in 2 mm. The program contributed to functional independence, improved quality of life, and social reintegration, suggesting the importance of a supervised physical activity program associated with adequate nutritional intake after multivisceral transplantation. Copyright © 2018 Elsevier Inc. All rights reserved.

Effects of gamma oryzanol supplementation on anthropometric measurements & muscular strength in healthy males following chronic resistance training.

PubMed

Eslami, Saghar; Esa, Norhaizan Mohd; Marandi, Seyed Mohammad; Ghasemi, Gholamali; Eslami, Sepehr

2014-06-01

Enhanced muscle strength is seen when resistance exercise is combined with the consumption of nutritional supplements. Although there is a limited number of studies available about the efficacy of gamma oryzanol supplementation with resistance exercise in humans, but its usage as a nutritional supplement for strength is common in athletes. The aim of this study was to determine the effects of gamma oryzanol supplementation during 9-week resistance training on muscular strength and anthropometric measurements of young healthy males. In this double-blind clinical trial, changes of anthropometric measurements and muscular strength were studied after chronic resistance exercise and gamma oryzanol supplementation in 30 healthy volunteers (16 in supplement and 14 in placebo). Each day, gamma oryzanol supplement (600 mg) and placebo (the same amount of lactose) were consumed after training. The participants exercised with 80 per cent 1-Repetition Maximum (1-RM), for one hour and four days/week. Anthropometric measurements and subjects' 1-RM for muscular strength were determined at the commencement and end of the 9-week study. There was no significant difference between the baseline characteristics and target variables at baseline between the two groups. After gamma oryzanol supplementation, there was no significant difference in the means of anthropometric and skin fold measurements between the supplement and placebo groups. However, there were significant differences between the supplement and placebo groups for 1-RM of bench press and leg curl, which showed that gamma oryzanol improved muscle strength following resistance training. Our findings indicated that 600 mg/day gamma oryzanol supplementation during the 9-week resistance training did not change anthropometric and body measurements, but it increased muscular strength in young healthy males. Further, studies need to be done in trained athletes, women, and in patients who suffer from muscular fatigue.

Relationships between maximal strength of lower limb, anthropometric characteristics and fundamental explosive performance in handball players.

PubMed

Hermassi, Souhail; Chelly, Mohamed Souhaiel; Wagner, Herbert; Fieseler, Georg; Schulze, Stephan; Delank, Karl-Stefan; Shephard, Roy J; Schwesig, René

2018-02-14

 The purpose of this study was to examine relationships between lower body muscular strength, anthropometric characteristics and several measures of explosive performance in elite team-handball players.  22 male elite team-handball players (age: 19.1 ± 1.7 years) were studied during the competitive season. Standard anthropometric and body composition measures included body mass index, lower limb and thigh muscle volume, and body fat percentage. Maximal leg strength was determined by a one-repetition maximum (1-RM) half back-squat. Vertical jump performance was assessed using a squat jump (SJ) and a counter movement jump (CMJ). Repeated shuttle-sprint ability (RSA) was tested by 6 (2 × 15 m) shuttle sprints with 20 s of active recovery intervals. The best time in a single shuttle sprint (30m; RSA best ), fastest total time (RSA TT ) and RSA test performance decrement (RSA dec ) were recorded. Agility was measured using a modified T-half test (MAT). Throwing velocities of jump shooting and 3-step throwing were recorded by digital video camera.  The explained variance of 1-RM half-back-squats ranged from 0.2 % (RSA% Fatigue Index) to 70.1 % (CMJ). Four out of 8 variables (RSA Best Time, CMJ, SJ, throwing velocity of jump shoot) demonstrated an r 2  > 0.5. Jump performances seemed closely related to 1-RM half-back-squats. Furthermore, 1-RM half-back-squats were positively correlated with leg and thigh muscle volumes (r = 0.652, r = 0.768).  The anthropometric characteristics and some physical performance tests are closely related to the maximal strength performance of handball players. Coaches should focus on maximal strength training programs for the lower limbs when seeking improvements in the throwing velocity and jump performance of handball players. © Georg Thieme Verlag KG Stuttgart · New York.

Comparing the performance-enhancing effects of squats on a vibration platform with conventional squats in recreationally resistance-trained men.

PubMed

Rønnestad, Bent R

2004-11-01

The purpose of this investigation was to compare the performance-enhancing effects of squats on a vibration platform with conventional squats in recreationally resistance-trained men. The subjects were 14 recreationally resistance-trained men (age, 21-40 years) and the intervention period consisted of 5 weeks. After the initial testing, subjects were randomly assigned to either the "squat whole body vibration" (SWBV) group (n = 7), which performed squats on a vibration platform on a Smith Machine, or the "squat"(S) group (n = 7), which performed conventional squats with no vibrations on a Smith Machine. Testing was performed at the beginning and the end of the study and consisted of 1 repetition maximum (1RM) in squat and maximum jump height in countermovement jump (CMJ). A modified daily undulating periodization program was used during the intervention period in both groups. Both groups trained at the same percentage of 1RM in squats (6-10RM). After the intervention, CMJ performance increased significantly only in the SWBV (p < 0.01), but there was no significant difference between groups in relative jump height increase (p = 0.088). Both groups showed significant increases in 1RM performance in squats (p < 0.01). Although there was a trend toward a greater relative strength increase in the SWBV group, it did not reach a significant level. In conclusion, the preliminary results of this study point toward a tendency of superiority of squats performed on a vibration platform compared with squats without vibrations regarding maximal strength and explosive power as long as the external load is similar in recreationally resistance-trained men.

The contribution of volume, technique, and load to single-repetition and total-repetition kinematics and kinetics in response to three loading schemes.

PubMed

Crewther, Blair T; Cronin, John; Keogh, Justin W L

2008-11-01

This study examined the effect of volume, technique, and load upon single-repetition and total-repetition kinematics and kinetics during three loading schemes. Eleven recreationally trained males each performed a power (8 sets of 6 repetitions at 45% of one-repetition maximum [1RM], 3-minute rest periods, explosive and ballistic movements), hypertrophy (10 sets of 10 repetitions at 75% 1RM, 2-minute rest periods, controlled movements), and maximal strength (6 sets of 4 repetitions at 88% 1RM, 4-minute rest periods, explosive intent) scheme involving squats. Examination of repetition data showed that load intensity (% 1RM) generally had a direct effect on forces, contraction times, impulses, and work (i.e., increasing with load), whereas power varied across loads (p < 0.001). However, total-repetition forces, contraction times, impulses, work, and power were all greater in the hypertrophy scheme (p < 0.001), because of the greater number of repetitions performed (volume) as well as lifting technique. No differences in total forces were found between the equal-volume power and maximal strength schemes, but the former did produce greater total contraction times, work, and power (p < 0.001), which may also be attributed to repetition and technique differences. Total impulses were the only variable greater in the maximal strength scheme (p < 0.001). Thus, the interaction of load, volume, and technique plays an important role in determining the mechanical responses (stimuli) afforded by these workouts. These findings may explain disparities cited within research, regarding the effectiveness of different loading strategies for hypertrophy, maximal strength, and power adaptation.

A comparison of muscle activation between a Smith machine and free weight bench press.

PubMed

Schick, Evan E; Coburn, Jared W; Brown, Lee E; Judelson, Daniel A; Khamoui, Andy V; Tran, Tai T; Uribe, Brandon P

2010-03-01

The bench press exercise exists in multiple forms including the machine and free weight bench press. It is not clear though how each mode differs in its effect on muscle activation. The purpose of this study was to compare muscle activation of the anterior deltoid, medial deltoid, and pectoralis major during a Smith machine and free weight bench press at lower (70% 1 repetition maximum [1RM]) and higher (90% 1RM) intensities. Normalized electromyography amplitude values were used during the concentric phase of the bench press to compare muscle activity between a free weight and Smith machine bench press. Participants were classified as either experienced or inexperienced bench pressers. Two testing sessions were used, each of which entailed either all free weight or all Smith machine testing. In each testing session, each participant's 1RM was established followed by 2 repetitions at 70% of 1RM and 2 repetitions at 90% of 1RM. Results indicated greater activation of the medial deltoid on the free weight bench press than on the Smith machine bench press. Also, there was greater muscle activation at the 90% 1RM load than at the 70% 1RM load. The results of this study suggest that strength coaches should consider choosing the free weight bench press over the Smith machine bench press because of its potential for greater upper-body muscular development.

Resistance training with creatine monohydrate improves upper-body strength in patients with Parkinson disease: a randomized trial.

PubMed

Hass, Chris J; Collins, Mitchell A; Juncos, Jorge L

2007-01-01

Persons with Parkinson disease (PD) exhibit decreased muscular fitness including decreased muscle mass, muscle strength, bioenergetic capabilities and increased fatigability. This purpose of this investigation was to evaluate the therapeutic effects of resistance training with and without creatine supplementation in patients with mild to moderate PD. Twenty patients with idiopathic PD were randomized to receive creatine monohydrate supplementation plus resistance training (CRE) or placebo (lactose monohydrate) plus resistance training (PLA), using a double-blind procedure. Creatine and placebo supplementation consisted of 20 g/d for the first 5 days and 5 g/d thereafter. Both groups participated in progressive resistance training (24 sessions, 2 times per week, 1 set of 8-12 repetitions, 9 exercises). Participants performed 1-repetition maximum (1-RM) for chest press, leg extension, and biceps curl. Muscular endurance was evaluated for chest press and leg extension as the number of repetitions to failure using 60% of baseline 1-RM. Functional performance was evaluated as the time to perform 3 consecutive chair rises. Statistical analyses (ANOVA) revealed significant Group x Time interactions for chest press strength and biceps curl strength, and post hoc testing revealed that the improvement was significantly greater for CRE. Chair rise performance significantly improved only for CRE (12%, P=.03). Both PLA and CRE significantly improved 1-RM for leg extension (PLA: 16%; CRE: 18%). Muscular endurance improved significantly for both groups. These findings demonstrate that creatine supplementation can enhance the benefits of resistance training in patients with PD.

Changes in muscle architecture and performance during a competitive season in female softball players.

PubMed

Nimphius, Sophia; McGuigan, Michael R; Newton, Robert U

2012-10-01

The purpose of this research was (a) to examine the performance changes that occur in elite female softball players during 20 weeks of softball training (that included 14 weeks of periodized resistance training [RT]) and (b) to examine the relationship between percent change (%change) in muscle architecture variables and %change in strength, speed, and change of direction performance. Ten female softball players (age = 18.1 ± 1.6 years, height = 166.5 ± 8.9 cm, weight = 72.4 ± 10.8 kg) from a state Australian Institute of Sport softball team were tested for maximal lower-body strength using a 3 repetition maximum for a predicted 1 repetition maximum (1RM) and peak force, peak velocity (PV), and peak power (PP) were measured during jump squats (JS) unloaded and loaded. In addition, the first base (1B) and the second base (2B) sprint performance, change of direction (505) on dominant (D) and nondominant (ND) sides, aerobic capacity, and muscle architecture characteristics of vastus lateralis (VL) including muscle thickness (MT), fascicle length (FL), and pennation angle (θp) were examined. The testing sessions occurred pre, mid, and post training (total 20 week pre- and in-season training period). Changes over time were analyzed by repeated-measures analysis of variance. The relationship between %change in muscle architecture variables and strength, speed, and change of direction variables from pre to post were assessed by Pearson product-moment correlation coefficient. Significant improvements in PV and PP occurred at all JS loads pre- to mid-testing and pre- to post-testing. Significant increases occurred pre-post in absolute 1RM, relative 1RM, 505 ND, and 2B sprint. The strongest relationships were found between %change in VL MT and 1B sprint (r = -0.80, p = 0.06), %change in VL FL and 2B sprint (r = -0.835, p = 0.02), and %change in relative 1RM and 505 D (r = -0.70, p = 0.04). In conclusion, gains in strength, power, and performance can occur during the season in elite softball players who are also engaged in a periodized RT program. Furthermore, changes in performance measures are associated with changes in muscle architecture.

Muscular power, neuromuscular activation, and performance in shot put athletes at preseason and at competition period.

PubMed

Kyriazis, Thomas A; Terzis, Gerasimos; Boudolos, Konstantinos; Georgiadis, Georgios

2009-09-01

The aim of this study was to investigate changes in shot put performance, muscular power, and neuromuscular activation of the lower extremities, between the preseason and the competition period, in skilled shot put athletes using the rotational technique. Shot put performance was assessed at the start of the pre-season period as well as after 12 weeks, at the competition period, in nine shot putters. Electromyographic (EMG) activity of the right vastus lateralis muscle was recorded during all shot put trials. Maximum squat strength (1RM) and mechanical parameters during the countermovement jump (CMJ) on a force platform were also determined at pre-season and at competition period. Shot put performance increased 4.7% (p < 0.05), while 1RM squat increased 6.5% (p < 0.025). EMG activity during the delivery phase was increased significantly (p < 0.025) after the training period. Shot put performance was significantly related with muscular power and takeoff velocity during the CMJ, at competition period (r = 0.66, p < 0.05 and 0.70, p < 0.05), but not with maximum vertical force. One RM squat was not related significantly with shot put performance. These results suggest that muscular power of the lower extremities is a better predictor of rotational shot put performance than absolute muscular strength in skilled athletes, at least during the competition period.

A whey protein-based multi-ingredient nutritional supplement stimulates gains in lean body mass and strength in healthy older men: A randomized controlled trial

PubMed Central

Bell, Kirsten E.; Snijders, Tim; Zulyniak, Michael; Kumbhare, Dinesh; Parise, Gianni; Chabowski, Adrian

2017-01-01

Protein and other compounds can exert anabolic effects on skeletal muscle, particularly in conjunction with exercise. The objective of this study was to evaluate the efficacy of twice daily consumption of a protein-based, multi-ingredient nutritional supplement to increase strength and lean mass independent of, and in combination with, exercise in healthy older men. Forty-nine healthy older men (age: 73 ± 1 years [mean ± SEM]; BMI: 28.5 ± 1.5 kg/m2) were randomly allocated to 20 weeks of twice daily consumption of either a nutritional supplement (SUPP; n = 25; 30 g whey protein, 2.5 g creatine, 500 IU vitamin D, 400 mg calcium, and 1500 mg n-3 PUFA with 700 mg as eicosapentanoic acid and 445 mg as docosahexanoic acid); or a control (n = 24; CON; 22 g of maltodextrin). The study had two phases. Phase 1 was 6 weeks of SUPP or CON alone. Phase 2 was a 12 week continuation of the SUPP/CON but in combination with exercise: SUPP + EX or CON + EX. Isotonic strength (one repetition maximum [1RM]) and lean body mass (LBM) were the primary outcomes. In Phase 1 only the SUPP group gained strength (Σ1RM, SUPP: +14 ± 4 kg, CON: +3 ± 2 kg, P < 0.001) and lean mass (LBM, +1.2 ± 0.3 kg, CON: -0.1 ± 0.2 kg, P < 0.001). Although both groups gained strength during Phase 2, upon completion of the study upper body strength was greater in the SUPP group compared to the CON group (Σ upper body 1RM: 119 ± 4 vs. 109 ± 5 kg, P = 0.039). We conclude that twice daily consumption of a multi-ingredient nutritional supplement increased muscle strength and lean mass in older men. Increases in strength were enhanced further with exercise training. Trial Registration: ClinicalTrials.gov NCT02281331 PMID:28719669

Analysis of postural control and muscular performance in young and elderly women in different age groups

PubMed Central

Gomes, Matheus M.; Reis, Júlia G.; Carvalho, Regiane L.; Tanaka, Erika H.; Hyppolito, Miguel A.; Abreu, Daniela C. C.

2015-01-01

BACKGROUND: muscle strength and power are two factors affecting balance. The impact of muscle strength and power on postural control has not been fully explored among different age strata over sixty. OBJECTIVES: the aim of the present study was to assess the muscle strength and power of elderly women in different age groups and determine their correlation with postural control. METHOD: eighty women were divided into four groups: the young 18-30 age group (n=20); the 60-64 age group (n=20); the 65-69 age group (n=20); and the 70-74 age group (n=20). The participants underwent maximum strength (one repetition maximum or 1-RM) and muscle power tests to assess the knee extensor and flexor muscles at 40%, 70%, and 90% 1-RM intensity. The time required by participants to recover their balance after disturbing their base of support was also assessed. RESULTS: the elderly women in the 60-64, 65-69, and 70-74 age groups exhibited similar muscle strength, power, and postural control (p>0.05); however, these values were lower than those of the young group (p<0.05) as expected. There was a correlation between muscle strength and power and the postural control performance (p<0.05). CONCLUSION: despite the age difference, elderly women aged 60 to 74 years exhibited similar abilities to generate strength and power with their lower limbs, and this ability could be one factor that explains the similar postural control shown by these women. PMID:25651132

RELIABILITY OF THE ONE REPETITION-MAXIMUM POWER CLEAN TEST IN ADOLESCENT ATHLETES

PubMed Central

Faigenbaum, Avery D.; McFarland, James E.; Herman, Robert; Naclerio, Fernando; Ratamess, Nicholas A.; Kang, Jie; Myer, Gregory D.

2013-01-01

Although the power clean test is routinely used to assess strength and power performance in adult athletes, the reliability of this measure in younger populations has not been examined. Therefore, the purpose of this study was to determine the reliability of the one repetition maximum (1 RM) power clean in adolescent athletes. Thirty-six male athletes (age 15.9 ± 1.1 yrs, body mass 79.1 ± 20.3 kg, height 175.1 ±7.4 cm) who had more than 1 year of training experience with weightlifting exercises performed a 1 RM power clean on two nonconsecutive days in the afternoon following standardized procedures. All test procedures were supervised by a senior level weightlifting coach and consisted of a systematic progression in test load until the maximum resistance that could be lifted for one repetition using proper exercise technique was determined. Data were analyzed using an intraclass correlation coefficient (ICC [2,k]), Pearson correlation coefficient (r), repeated measures ANOVA, Bland-Altman plot, and typical error analyses. Analysis of the data revealed that the test measures were highly reliable demonstrating a test-retest ICC of 0.98 (95% CI = 0.96–0.99). Testing also demonstrated a strong relationship between 1 RM measures on trial 1 and trial 2 (r=0.98, p<0.0001) with no significant difference in power clean performance between trials (70.6 ± 19.8 vs. 69.8 ± 19.8 kg). Bland Altman plots confirmed no systematic shift in 1 RM between trial 1 and trial 2. The typical error to be expected between 1 RM power clean trials is 2.9 kg and a change of at least 8.0 kg is indicated to determine a real change in lifting performance between tests in young lifters. No injuries occurred during the study period and the testing protocol was well-tolerated by all subjects. These findings indicate that 1 RM power clean testing has a high degree of reproducibility in trained male adolescent athletes when standardized testing procedures are followed and qualified instruction is present. PMID:22233786

Weaker lower extremity muscle strength predicts traumatic knee injury in youth female but not male athletes

PubMed Central

Ryman Augustsson, Sofia; Ageberg, Eva

2017-01-01

Background The role of lower extremity (LE) muscle strength for predicting traumatic knee injury in youth athletes is largely unknown. Aims The aim was to investigate the influence of LE muscle strength on traumatic knee injury in youth female and male athletes. Methods 225 athletes (40% females) from sport senior high schools in Sweden were included in this case–control study. The athletes recorded any traumatic knee injury that had occurred during their high-school period in a web-based injury form. A one repetition maximum (1RM) barbell squat test was used to measure LE muscle strength. The 1RM was dichotomised to analyse ‘weak’ versus ‘strong’ athletes according to the median (weakmedian vs strongmedian). Results 63 traumatic knee injuries, including 18 ACL injuries, were registered. The majority of injured female athletes were in the weak group compared with the strong group (p=0.0001). The odds of sustaining a traumatic knee injury and an ACL injury was 9.5 times higher and 7 times higher, respectively, in the weakmedian group compared with the strongmedian group in females (p ≤0.011). A relative 1RM squat ≤1.05 kg (105% of bodyweight) was established as the best cut-off value to distinguish high versus low risk of injury in female athletes. No strength–injury relationships were observed for the male athletes (p ≥0.348). Conclusions Weaker LE muscle strength predicted traumatic knee injury in youth female athletes, but not in males. This suggests that LE muscle strength should be included in injury screening in youth female athletes. PMID:29259807

Improvement of Ice Hockey Players' On-Ice Sprint With Combined Plyometric and Strength Training.

PubMed

Dæhlin, Torstein E; Haugen, Ole C; Haugerud, Simen; Hollan, Ivana; Raastad, Truls; Rønnestad, Bent R

2017-08-01

Combined plyometric and strength training has previously been suggested as a strategy to improve skating performance in ice hockey players. However, the effects of combined plyometric and strength training have not previously been compared with the effects of strength training only. To compare the effects of combined plyometric and strength training on ice hockey players' skating sprint performance with those of strength training only. Eighteen participants were randomly assigned to 2 groups that completed 5 strength-training sessions/wk for 8 wk. One group included plyometric exercises at the start of 3 sessions/wk (PLY+ST), and the other group included core exercises in the same sessions (ST). Tests of 10- and 35-m skating sprints, horizontal jumping, 1-repetition-maximum (1 RM) squat, skating multistage aerobic test (SMAT), maximal oxygen consumption, repeated cycle sprints, and body composition were performed before and after the intervention. The participants increased their 1RM squat, lean mass, and body mass (P < .05), with no difference between the groups. Furthermore, they improved their 3×broad jump, repeated cycle sprint, and SMAT performance (P < .05), with no difference between the groups. PLY+ST gained a larger improvement in 10-m on-ice sprint performance than ST (P < .025). Combining plyometric and strength training for 8 wk was superior to strength training alone at improving 10-m on-ice sprint performance in high-level ice hockey players.

Selective effects of different fatigue protocols on the function of upper body muscles assessed through the force-velocity relationship.

PubMed

García-Ramos, Amador; Torrejón, Alejandro; Feriche, Belén; Morales-Artacho, Antonio J; Pérez-Castilla, Alejandro; Padial, Paulino; Jaric, Slobodan

2018-02-01

This study explored the feasibility of the force-velocity relationship (F-V) to detect the acute effects of different fatigue protocols on the selective changes of the maximal capacities of upper body muscles to produce force, velocity, and power. After determining the bench press one-repetition maximum (1RM), participants' F-V relationships were assessed during the bench press throw exercise on five separate sessions after performing one of the following fatiguing protocols: 60%1RM failure, 60%1RM non-failure, 80%1RM failure, 80%1RM non-failure, and no-fatigue. In the non-failure protocols, participants performed half the maximum number of repetitions than in their respective failure protocols. The main findings revealed that (1) all F-V relationships were highly linear (median r = 0.997 and r = 0.982 for averaged across participants and individual data, respectively), (2) the fatiguing protocols were ranked based on the magnitude of power loss as follows: 60%1RM failure > 80%1RM failure > 60%1RM non-failure > 80%1RM non-failure, while (3) the assessed maximum force and velocity outputs showed a particularly prominent reduction in the protocols based on the lowest and highest levels of fatigue (i.e., 80%1RM non-failure and 60%1RM failure), respectively. The results support the use of F-V to assess the effects of fatigue on the distinctive capacities of the muscles to produce force, velocity, and power output while performing multi-joint tasks, while the assessed maximum force and velocity capacities showed a particularly prominent reduction in the protocols based on the lowest and highest levels of fatigue (i.e., 80%1RM non-failure and 60%1RM failure), respectively.

Estimation of 1RM for knee extension based on the maximal isometric muscle strength and body composition.

PubMed

Kanada, Yoshikiyo; Sakurai, Hiroaki; Sugiura, Yoshito; Arai, Tomoaki; Koyama, Soichiro; Tanabe, Shigeo

2017-11-01

[Purpose] To create a regression formula in order to estimate 1RM for knee extensors, based on the maximal isometric muscle strength measured using a hand-held dynamometer and data regarding the body composition. [Subjects and Methods] Measurement was performed in 21 healthy males in their twenties to thirties. Single regression analysis was performed, with measurement values representing 1RM and the maximal isometric muscle strength as dependent and independent variables, respectively. Furthermore, multiple regression analysis was performed, with data regarding the body composition incorporated as another independent variable, in addition to the maximal isometric muscle strength. [Results] Through single regression analysis with the maximal isometric muscle strength as an independent variable, the following regression formula was created: 1RM (kg)=0.714 + 0.783 × maximal isometric muscle strength (kgf). On multiple regression analysis, only the total muscle mass was extracted. [Conclusion] A highly accurate regression formula to estimate 1RM was created based on both the maximal isometric muscle strength and body composition. Using a hand-held dynamometer and body composition analyzer, it was possible to measure these items in a short time, and obtain clinically useful results.

Salivary hormone and immune responses to three resistance exercise schemes in elite female athletes.

PubMed

Nunes, João A; Crewther, Blair T; Ugrinowitsch, Carlos; Tricoli, Valmor; Viveiros, Luís; de Rose, Dante; Aoki, Marcelo S

2011-08-01

This study examined the salivary hormone and immune responses of elite female athletes to 3 different resistance exercise schemes. Fourteen female basketball players each performed an endurance scheme (ES-4 sets of 12 reps, 60% of 1 repetition maximum (1RM) load, 1-minute rest periods), a strength-hypertrophy scheme (SHS-1 set of 5RM, 1 set of 4RM, 1 set of 3RM, 1 set of 2RM, and 1set of 1RM with 3-minute rest periods, followed by 3 sets of 10RM with 2-minute rest periods) and a power scheme (PS-3 sets of 10 reps, 50% 1RM load, 3-minute rest periods) using the same exercises (bench press, squat, and biceps curl). Saliva samples were collected at 07:30 hours, pre-exercise (Pre) at 09:30 hours, postexercise (Post), and at 17:30 hours. Matching samples were also taken on a nonexercising control day. The samples were analyzed for testosterone, cortisol (C), and immunoglobulin A concentrations. The total volume of load lifted differed among the 3 schemes (SHS > ES > PS, p < 0.05). Postexercise C concentrations increased after all schemes, compared to control values (p < 0.05). In the SHS, the postexercise C response was also greater than pre-exercise data (p < 0.05). The current findings confirm that high-volume resistance exercise schemes can stimulate greater C secretion because of higher metabolic demand. In terms of practical applications, acute changes in C may be used to evaluate the metabolic demands of different resistance exercise schemes, or as a tool for monitoring training strain.

Force-Velocity-Power Assessment in Semiprofessional Rugby Union Players.

PubMed

McMaster, Daniel T; Gill, Nicholas D; Cronin, John B; McGuigan, Michael R

2016-04-01

There is a constant and necessary evolution of training and assessment methods in the elite contact sports; as is required to continually improve the physical qualities of these respective athletes to match the growing sport and position-specific performance demands. Our aim was to examine the differences between ballistic upper body performance profiles and maximum upper body strength of elite rugby union forwards and backs. Twenty semiprofessional male rugby union players (age = 21.1 ± 3.0 years; mass = 94.9 ± 9.7 kg) were assessed for maximum bench press strength (1RM bench press = 121.3 ± 21.8 kg) and maximum throw power (Pmax), force (Fmax), and velocity (V[Combining Dot Above]max) from an incremental relative load testing protocol (15, 30, 45, 60, and 75% 1RM). Player rankings were also included to identify individual strength and weaknesses. The forwards were moderately stronger (effect size [ES] = 0.96; p = 0.01), produced significantly greater Fmax (ES = 1.17-1.41; p = 0.01) and were more powerful (ES = 0.57-0.64; p < 0.43) than the backs. V[Combining Dot Above]max differences were trivial to small (ES = -0.32 to -0.65; p > 0.15). There were inherent differences in strength and Fmax between the forwards and backs most likely because of the physical demands of these respective positions. Improvements in upper body strength may in turn improve ballistic force and power production, but not necessarily velocity capabilities. From the Fmax and V[Combining Dot Above]max observations, the forwards seem to be more force dominant and the backs more velocity dominant. Pmax, Fmax, and V[Combining Dot Above]max may be used to highlight proficient and deficient areas in ballistic upper body performance; the individual rankings could be further used to identify and possibly rectify individual deficiencies.

The effects of training with loads that maximise power output and individualised repetitions vs. traditional power training

PubMed Central

Moya-Ramón, M.; Hernández-Davó, J. L.; Fernandez-Fernandez, J.; Sabido, R.

2017-01-01

Background It has been suggested that strength training effects (i.e. neural or structural) vary, depending on the total repetitions performed and velocity loss in each training set. Purpose The aim of this study is to compare the effects of two training programmes (i.e. one with loads that maximise power output and individualised repetitions, and the other following traditional power training). Methods Twenty-five males were divided into three groups (optimum power [OP = 10], traditional training [TT = 9] and control group [CG = 6]). The training load used for OP was individualised using loads that maximised power output (41.7% ± 5.8 of one repetition maximum [1RM]) and repetitions at maximum power (4 to 9 repetitions, or ‘reps’). Volume (sets x repetitions) was the same for both experimental groups, while intensity for TT was that needed to perform only 50% of the maximum number of possible repetitions (i.e. 61.1%–66.6% of 1RM). The training programme ran over 11 weeks (2 sessions per week; 4–5 sets per session; 3-minute rests between sets), with pre-, intermediate and post-tests which included: anthropometry, 1RM, peak power output (PPO) with 30%, 40% and 50% of 1RM in the bench press throw, and salivary testosterone (ST) and cortisol (SC) concentrations. Rate of perceived exertion (RPE) and power output were recorded in all sessions. Results Following the intermediate test, PPO was increased in the OP group for each load (10.9%–13.2%). Following the post-test, both experimental groups had increased 1RM (11.8%–13.8%) and PPO for each load (14.1%–19.6%). Significant decreases in PPO were found for the TT group during all sets (4.9%–15.4%), along with significantly higher RPE (37%). Conclusion OP appears to be a more efficient method of training, with less neuromuscular fatigue and lower RPE. PMID:29053725

Adaptations in athletic performance after ballistic power versus strength training.

PubMed

Cormie, Prue; McGuigan, Michael R; Newton, Robert U

2010-08-01

To determine whether the magnitude of improvement in athletic performance and the mechanisms driving these adaptations differ in relatively weak individuals exposed to either ballistic power training or heavy strength training. Relatively weak men (n = 24) who could perform the back squat with proficient technique were randomized into three groups: strength training (n = 8; ST), power training (n = 8; PT), or control (n = 8). Training involved three sessions per week for 10 wk in which subjects performed back squats with 75%-90% of one-repetition maximum (1RM; ST) or maximal-effort jump squats with 0%-30% 1RM (PT). Jump and sprint performances were assessed as well as measures of the force-velocity relationship, jumping mechanics, muscle architecture, and neural drive. Both experimental groups showed significant (P < or = 0.05) improvements in jump and sprint performances after training with no significant between-group differences evident in either jump (peak power: ST = 17.7% +/- 9.3%, PT = 17.6% +/- 4.5%) or sprint performance (40-m sprint: ST = 2.2% +/- 1.9%, PT = 3.6% +/- 2.3%). ST also displayed a significant increase in maximal strength that was significantly greater than the PT group (squat 1RM: ST = 31.2% +/- 11.3%, PT = 4.5% +/- 7.1%). The mechanisms driving these improvements included significant (P < or = 0.05) changes in the force-velocity relationship, jump mechanics, muscle architecture, and neural activation that showed a degree of specificity to the different training stimuli. Improvements in athletic performance were similar in relatively weak individuals exposed to either ballistic power training or heavy strength training for 10 wk. These performance improvements were mediated through neuromuscular adaptations specific to the training stimulus. The ability of strength training to render similar short-term improvements in athletic performance as ballistic power training, coupled with the potential long-term benefits of improved maximal strength, makes strength training a more effective training modality for relatively weak individuals.

Relationships between Mechanical Variables in the Traditional and Close-Grip Bench Press.

PubMed

Lockie, Robert G; Callaghan, Samuel J; Moreno, Matthew R; Risso, Fabrice G; Liu, Tricia M; Stage, Alyssa A; Birmingham-Babauta, Samantha A; Stokes, John J; Giuliano, Dominic V; Lazar, Adrina; Davis, DeShaun L; Orjalo, Ashley J

2017-12-01

The study aim was to determine relationships between mechanical variables in the one-repetition maximum (1RM) traditional bench press (TBP) and close-grip bench press (CGBP). Twenty resistance-trained men completed a TBP and CGBP 1RM. The TBP was performed with the preferred grip; the CGBP with a grip width of 95% biacromial distance. A linear position transducer measured: lift distance and duration; work; and peak and mean power, velocity, and force. Paired samples t-tests (p < 0.05) compared the 1RM and mechanical variables for the TBP and CGBP; effect sizes (d) were also calculated. Pearson's correlations (r; p < 0.05) computed relationships between the TBP and CGBP. 1RM, lift duration, and mean force were greater in the TBP (d = 0.30-3.20). Peak power and velocity was greater for the CGBP (d = 0.50-1.29). The 1RM TBP correlated with CGBP 1RM, power, and force (r = 0.685-0.982). TBP work correlated with CGBP 1RM, lift distance, power, force, and work (r = 0.542-0.931). TBP power correlated with CGBP 1RM, power, force, velocity, and work (r = 0.484-0.704). TBP peak and mean force related to CGBP 1RM, power, and force (r = 0.596-0.980). Due to relationships between the load, work, power, and force for the TBP and CGBP, the CGBP could provide similar strength adaptations to the TBP with long-term use. The velocity profile for the CGBP was different to that of the TBP. The CGBP could be used specifically to improve high-velocity, upper-body pushing movements.

Relationships between Mechanical Variables in the Traditional and Close-Grip Bench Press

PubMed Central

Callaghan, Samuel J.; Moreno, Matthew R.; Risso, Fabrice G.; Liu, Tricia M.; Stage, Alyssa A.; Birmingham-Babauta, Samantha A.; Stokes, John J.; Giuliano, Dominic V.; Lazar, Adrina; Davis, DeShaun L.; Orjalo, Ashley J.

2017-01-01

Abstract The study aim was to determine relationships between mechanical variables in the one-repetition maximum (1RM) traditional bench press (TBP) and close-grip bench press (CGBP). Twenty resistance-trained men completed a TBP and CGBP 1RM. The TBP was performed with the preferred grip; the CGBP with a grip width of 95% biacromial distance. A linear position transducer measured: lift distance and duration; work; and peak and mean power, velocity, and force. Paired samples t-tests (p < 0.05) compared the 1RM and mechanical variables for the TBP and CGBP; effect sizes (d) were also calculated. Pearson’s correlations (r; p < 0.05) computed relationships between the TBP and CGBP. 1RM, lift duration, and mean force were greater in the TBP (d = 0.30-3.20). Peak power and velocity was greater for the CGBP (d = 0.50-1.29). The 1RM TBP correlated with CGBP 1RM, power, and force (r = 0.685-0.982). TBP work correlated with CGBP 1RM, lift distance, power, force, and work (r = 0.542-0.931). TBP power correlated with CGBP 1RM, power, force, velocity, and work (r = 0.484-0.704). TBP peak and mean force related to CGBP 1RM, power, and force (r = 0.596-0.980). Due to relationships between the load, work, power, and force for the TBP and CGBP, the CGBP could provide similar strength adaptations to the TBP with long-term use. The velocity profile for the CGBP was different to that of the TBP. The CGBP could be used specifically to improve high-velocity, upper-body pushing movements. PMID:29339982

Chain-loaded variable resistance warm-up improves free-weight maximal back squat performance.

PubMed

Mina, Minas A; Blazevich, Anthony J; Giakas, Giannis; Seitz, Laurent B; Kay, Anthony D

2016-11-01

The acute influence of chain-loaded variable resistance exercise on subsequent free-weight one-repetition maximum (1-RM) back squat performance was examined in 16 recreationally active men. The participants performed either a free-weight resistance (FWR) or chain-loaded resistance (CLR) back squat warm-up at 85% 1-RM on two separate occasions. After a 5-min rest, the participants attempted a free-weight 1-RM back squat; if successful, subsequent 5% load additions were made until participants failed to complete the lift. During the 1-RM trials, 3D knee joint kinematics and knee extensor and flexor electromyograms (EMG) were recorded simultaneously. Significantly greater 1-RM (6.2 ± 5.0%; p < .01) and mean eccentric knee extensor EMG (32.2 ± 6.7%; p < .01) were found after the CLR warm-up compared to the FWR condition. However, no difference (p > .05) was found in concentric EMG, eccentric or concentric knee angular velocity, or peak knee flexion angle. Performing a CLR warm-up enhanced subsequent free-weight 1-RM performance without changes in knee flexion angle or eccentric and concentric knee angular velocities; thus a real 1-RM increase was achieved as the mechanics of the lift were not altered. These results are indicative of a potentiating effect of CLR in a warm-up, which may benefit athletes in tasks where high-level strength is required.

Bioresorbable screws reinforced with phosphate glass fibre: manufacturing and mechanical property characterisation.

PubMed

Felfel, R M; Ahmed, I; Parsons, A J; Rudd, C D

2013-01-01

Use of bioresorbable screws could eliminate disadvantages associated with metals such as removal operations, corrosion, MRI interference and stress shielding. Mechanical properties of bioresorbable polymers alone are insufficient for load bearing applications application as screws. Thus, reinforcement is necessary to try and match or surpass the mechanical properties of cortical bone. Phosphate based glass fibres were used to reinforce polylactic acid (PLA) in order to produce unidirectionally aligned (UD) and unidirectionally plus randomly distributed (UD/RM) composite screws (P40 UD and P40 UD/RM). The maximum flexural and push-out properties for the composite screws (P40 UD and P40 UD/RM) increased by almost 100% in comparison with the PLA screws. While the pull-out strength and stiffness of the headless composite screws were ∼80% (strength) and ∼130% (stiffness) higher than for PLA, those with heads exhibited properties lower than those for PLA alone as a result of failure at the heads. An increase in the maximum shear load and stiffness for the composite screws (∼30% and ∼40%) in comparison to the PLA screws was also seen. Maximum torque for the PLA screws was ∼1000 mN m, while that for the composite screws were slightly lower. The SEM micrographs for P40 UD and P40 UD/RM screws revealed small gaps around the fibres, which were suggested to be due to buckling of the UD fibres during the manufacturing process. Copyright © 2012 Elsevier Ltd. All rights reserved.

Ancient peat and apple extracts supplementation may improve strength and power adaptations in resistance trained men.

PubMed

Joy, Jordan M; Vogel, Roxanne M; Moon, Jordan R; Falcone, Paul H; Mosman, Matt M; Pietrzkowski, Zbigniew; Reyes, Tania; Kim, Michael P

2016-07-18

Increased cellular ATP levels have the potential to enhance athletic performance. A proprietary blend of ancient peat and apple extracts has been supposed to increase ATP production. Therefore, the purpose of this investigation was to determine the effects of this supplement on athletic performance when used during 12 weeks of supervised, periodized resistance training. Twenty-five healthy, resistance-trained, male subjects completed this study. Subjects supplemented once daily with either 1 serving (150 mg) of a proprietary blend of ancient peat and apple extract (TRT) or an equal-volume, visually-identical placebo (PLA) daily. Supervised resistance training consisted of 8 weeks of daily undulating periodized training followed by a 2 week overreach and a 2 week taper phase. Strength was determined using 1-repetition-maximum (1RM) testing in the barbell back squat, bench press (BP), and deadlift exercises. Peak power and peak velocity were determined during BP at 30 % 1RM and vertical jump tests as well as a 30s Wingate test, which also provided relative power (watt:mass) A group x time interaction was present for squat 1RM, deadlift 1RM, and vertical jump peak power and peak velocity. Squat and deadlift 1RM increased in TRT versus PLA from pre to post. Vertical jump peak velocity increased in TRT versus PLA from pre to week 10 as did vertical jump peak power, which also increased from pre to post. Wingate peak power and watt:mass tended to favor TRT. Supplementing with ancient peat and apple extract while participating in periodized resistance training may enhance performance adaptations. ClinicalTrials.gov registration ID: NCT02819219 , retrospectively registered on 6/29/2016.

Power and impulse applied during push press exercise.

PubMed

Lake, Jason P; Mundy, Peter D; Comfort, Paul

2014-09-01

The aim of this study was to quantify the load, which maximized peak and mean power, and impulse applied to these loads, during the push press and to compare them to equivalent jump squat data. Resistance-trained men performed 2 push press (n = 17; age: 25.4 ± 7.4 years; height: 183.4 ± 5 cm; body mass: 87 ± 15.6 kg) and jump squat (n = 8 of original 17; age: 28.7 ± 8.1 years; height: 184.3 ± 5.5 cm; mass: 98 ± 5.3 kg) singles with 10-90% of their push press and back squat 1 repetition maximum (1RM), respectively, in 10% 1RM increments while standing on a force platform. Push press peak and mean power was maximized with 75.3 ± 16.4 and 64.7 ± 20% 1RM, respectively, and impulses applied to these loads were 243 ± 29 N·s and 231 ± 36 N·s. Increasing and decreasing load, from the load that maximized peak and mean power, by 10 and 20% 1RM reduced peak and mean power by 6-15% (p ≤ 0.05). Push press and jump squat maximum peak power (7%, p = 0.08) and the impulse that was applied to the load that maximized peak (8%, p = 0.17) and mean (13%, p = 0.91) power were not significantly different, but push press maximum mean power was significantly greater than the jump squat equivalent (∼9.5%, p = 0.03). The mechanical demand of the push press is comparable with the jump squat and could provide a time-efficient combination of lower-body power and upper-body and trunk strength training.

The influence of somatotype on anaerobic performance

PubMed Central

Faulkner, James; Jobson, Simon

2018-01-01

The link between athlete physique and performance in sports is well established. However, a direct link between somatotype three-numeral rating and anaerobic performance has not yet been reported. The purpose of this study was to assess the relations between somatotype and anaerobic performance using both singular and multivariate analyses. Thirty-six physically active males (mean ± standard deviation age 26.0 ± 9.8 years; body mass 79.5 ± 12.9 kg; height 1.82 ± 0.07 m) were somatotype-rated using the Heath-Carter method. Subjects were assessed for 3 repetition maximum (3 RM) bench press and back squat, and completed a 30-second maximal sprint cycle test. Positive correlations were observed between mesomorphy and 3 RM bench press (r = 0.560, p < 0.001), mesomorphy and 3 RM back squat (r = 0.550, p = 0.001) and between mesomorphy and minimum power output (r = 0.357, p = 0.033). Negative correlations were observed between ectomorphy and 3 RM bench press (r = -0.381, p = 0.022), and ectomorphy and 3 RM back squat (r = -0.336, p = 0.045). Individual regression analysis indicated that mesomorphy was the best predictor of 3 RM bench press performance, with 31.4% of variance in 3 RM bench press performance accounted for by the mesomorphy rating (p < 0.001). A combination of mesomorphy and ectomorphy best predicted 3 RM back squat performance (R2 = 0.388, p < 0.04). Around one third of strength performance is predicted by somatotype-assessed physique in physically active males. This could have important implications for the identification of those predisposed to perform well in sports containing strength-based movements and prescription of training programmes. PMID:29787610

The influence of somatotype on anaerobic performance.

PubMed

Ryan-Stewart, Helen; Faulkner, James; Jobson, Simon

2018-01-01

The link between athlete physique and performance in sports is well established. However, a direct link between somatotype three-numeral rating and anaerobic performance has not yet been reported. The purpose of this study was to assess the relations between somatotype and anaerobic performance using both singular and multivariate analyses. Thirty-six physically active males (mean ± standard deviation age 26.0 ± 9.8 years; body mass 79.5 ± 12.9 kg; height 1.82 ± 0.07 m) were somatotype-rated using the Heath-Carter method. Subjects were assessed for 3 repetition maximum (3 RM) bench press and back squat, and completed a 30-second maximal sprint cycle test. Positive correlations were observed between mesomorphy and 3 RM bench press (r = 0.560, p < 0.001), mesomorphy and 3 RM back squat (r = 0.550, p = 0.001) and between mesomorphy and minimum power output (r = 0.357, p = 0.033). Negative correlations were observed between ectomorphy and 3 RM bench press (r = -0.381, p = 0.022), and ectomorphy and 3 RM back squat (r = -0.336, p = 0.045). Individual regression analysis indicated that mesomorphy was the best predictor of 3 RM bench press performance, with 31.4% of variance in 3 RM bench press performance accounted for by the mesomorphy rating (p < 0.001). A combination of mesomorphy and ectomorphy best predicted 3 RM back squat performance (R2 = 0.388, p < 0.04). Around one third of strength performance is predicted by somatotype-assessed physique in physically active males. This could have important implications for the identification of those predisposed to perform well in sports containing strength-based movements and prescription of training programmes.

Different loading schemes in power training during the preseason promote similar performance improvements in Brazilian elite soccer players.

PubMed

Loturco, Irineu; Ugrinowitsch, Carlos; Tricoli, Valmor; Pivetti, Bruno; Roschel, Hamilton

2013-07-01

The present study investigated the effects of 2 different power training loading schemes in Brazilian elite soccer players. Thirty-two players participated in the study. Maximum dynamic strength (1RM) was evaluated before (B), at midpoint (i.e., after 3 weeks; T1), and after 6 weeks (T2) of a preseason strength/power training. Muscle power, jumping, and sprinting performance were evaluated at B and T2. Players were randomly allocated to 1 of 2 training groups: velocity-based (VEL: n = 16; age, 19.18 ± 0.72 years; height, 173 ± 6 cm; body mass, 72.7 ± 5.8 kg) or intensity-based (INT: n = 16; age, 19.11 ± 0.7 years; height, 172 ± 4.5 cm; body mass, 71.8 ± 4.6 kg). After the individual determination of the optimal power load, both groups completed a 3-week traditional strength training period. Afterward, the VEL group performed 3 weeks of power-oriented training with increasing velocity and decreasing intensity (from 60 to 30% 1RM) throughout the training period, whereas the INT group increased the training intensity (from 30 to 60% 1RM) and thus decreased movement velocity throughout the power-oriented training period. Both groups used loads within ±15% (ranging from 30 to 60% 1RM) of the measured optimal power load (i.e., 45.2 ± 3.0% 1RM). Similar 1RM gains were observed in both groups at T1 (VEL: 9.2%; INT: 11.0%) and T2 (VEL: 19.8%; INT: 22.1%). The 2 groups also presented significant improvements (within-group comparisons) in all of the variables. However, no between-group differences were detected. Mean power in the back squat (VEL: 18.5%; INT: 20.4%) and mean propulsive power in the jump squat (VEL: 29.1%; INT: 31.0%) were similarly improved at T2. The 10-m sprint (VEL: -4.3%; INT: -1.6%), jump squat (VEL: 7.1%; INT: 4.5%), and countermovement jump (VEL: 6.7%; INT: 6.9%) were also improved in both groups at T2. Curiously, the 30-m sprint time (VEL: -0.8%; INT: -0.1%) did not significantly improve for both groups. In summary, our data suggest that male professional soccer players can achieve improvements in strength- and power-related abilities as a result of 6 weeks of power-oriented training during the preseason. Furthermore, similar performance improvements are observed when training intensity manipulation occurs around only a small range within the optimal power training load.

Effects of gamma oryzanol supplementation on anthropometric measurements & muscular strength in healthy males following chronic resistance training

PubMed Central

Eslami, Saghar; Esa, Norhaizan Mohd; Marandi, Seyed Mohammad; Ghasemi, Gholamali; Eslami, Sepehr

2014-01-01

Background & objectives: Enhanced muscle strength is seen when resistance exercise is combined with the consumption of nutritional supplements. Although there is a limited number of studies available about the efficacy of gamma oryzanol supplementation with resistance exercise in humans, but its usage as a nutritional supplement for strength is common in athletes. The aim of this study was to determine the effects of gamma oryzanol supplementation during 9-week resistance training on muscular strength and anthropometric measurements of young healthy males. Methods: In this double-blind clinical trial, changes of anthropometric measurements and muscular strength were studied after chronic resistance exercise and gamma oryzanol supplementation in 30 healthy volunteers (16 in supplement and 14 in placebo). Each day, gamma oryzanol supplement (600 mg) and placebo (the same amount of lactose) were consumed after training. The participants exercised with 80 per cent 1-Repetition Maximum (1-RM), for one hour and four days/week. Anthropometric measurements and subjects’ 1-RM for muscular strength were determined at the commencement and end of the 9-week study. Results: There was no significant difference between the baseline characteristics and target variables at baseline between the two groups. After gamma oryzanol supplementation, there was no significant difference in the means of anthropometric and skin fold measurements between the supplement and placebo groups. However, there were significant differences between the supplement and placebo groups for 1-RM of bench press and leg curl, which showed that gamma oryzanol improved muscle strength following resistance training. Interpretation & conclusions: Our findings indicated that 600 mg/day gamma oryzanol supplementation during the 9-week resistance training did not change anthropometric and body measurements, but it increased muscular strength in young healthy males. Further, studies need to be done in trained athletes, women, and in patients who suffer from muscular fatigue. PMID:25109720

Changes in fitness and shipboard task performance following circuit weight training programs featuring continuous or interval running.

PubMed

Marcinik, E J; Hodgdon, J A; Englund, C E; O'Brien, J J

1987-01-01

Pre- and post-physiological data were collected on 57 Navy men (mean age = 19.5 years) who participated in either circuit weight training/continuous run (CWT/CR) (N = 31) or circuit weight training/interval run (CWT/IR) (N = 26) programs. Measured variables included 4 measures of upper torso dynamic strength (one repetition maximum [1 RM] for arm curl, bench press, shoulder press, and lat pull-down); two measures of lower torso dynamic strength (1 RM) for knee extension and leg press); one measure of power (number of revolutions completed on an arm ergometer (Monark) at maximum drag); three measures of muscular endurance (number of repetitions at 60% 1 RM for bench press and leg press and maximal number of bent-knee sit-ups in 120 s); one stamina measure (time to exhaustion on a cycle ergometer (Monark) maximal work capacity [MWC] test; and three simulated shipboard tasks: manikin shoulder drag, open/secure a water tight door and paint bucket carry. Composite shipboard performance derived from the summed time (s) required to complete the three tasks was also calculated. Results show performance on the manikin shoulder drag and majority of evaluative fitness measures was significantly (p less than 0.05) enhanced following both circuit weight training/run formats. Significantly (p less than 0.05) higher values for shoulder press (F = 7.2), arm ergometer (F = 5.3), and sit-ups (F = 6.8) and lower values for leg press muscular endurance (F = 5.1) were observed in CWT/IR when compared to CWT/CR.(ABSTRACT TRUNCATED AT 250 WORDS)

Physical Employment Standards for UK Firefighters

PubMed Central

Stevenson, Richard D.M.; Siddall, Andrew G.; Turner, Philip F.J.; Bilzon, James L.J.

2017-01-01

Objective: The aim of this study was to assess sensitivity and specificity of surrogate physical ability tests as predictors of criterion firefighting task performance and to identify corresponding minimum muscular strength and endurance standards. Methods: Fifty-one (26 male; 25 female) participants completed three criterion tasks (ladder lift, ladder lower, ladder extension) and three corresponding surrogate tests [one-repetition maximum (1RM) seated shoulder press; 1RM seated rope pull-down; repeated 28 kg seated rope pull-down]. Surrogate test standards were calculated that best identified individuals who passed (sensitivity; true positives) and failed (specificity; true negatives) criterion tasks. Results: Best sensitivity/specificity achieved were 1.00/1.00 for a 35 kg seated shoulder press, 0.79/0.92 for a 60 kg rope pull-down, and 0.83/0.93 for 23 repetitions of the 28 kg rope pull-down. Conclusions: These standards represent performance on surrogate tests commensurate with minimum acceptable performance of essential strength-based occupational tasks in UK firefighters. PMID:28045801

The Effect of High-Intensity Interval Cycling Sprints Subsequent to Arm-Curl Exercise on Upper-Body Muscle Strength and Hypertrophy.

PubMed

Kikuchi, Naoki; Yoshida, Shou; Okuyama, Mizuki; Nakazato, Koichi

2016-08-01

Kikuchi, N, Yoshida, S, Okuyama, M, and Nakazato, K. The effect of high-intensity interval cycling sprints subsequent to arm-curl exercise on upper-body muscle strength and hypertrophy. J Strength Cond Res 30(8): 2318-2323, 2016-The purpose of this study was to examine whether lower limb sprint interval training (SIT) after arm resistance training (RT) influences training response of arm muscle strength and hypertrophy. Twenty men participated in this study. We divided subjects into RT group (n = 6) and concurrent training group (CT, n = 6). The RT program was designed to induce muscular hypertrophy (3 sets × 10 repetitions [reps] at 80% 1 repetition maximum [1RM] of arm-curl exercise) and was performed in an 8-week training schedule performed 3 times per week on nonconsecutive days. Subjects assigned to the CT group performed identical protocols as strength training and modified SIT (4 sets of 30-s maximal effort, separated in 4 m 30-s rest intervals) on the same day. Pretest and posttest maximal oxygen consumption (V[Combining Dot Above]O2max), muscle cross-sectional area (CSA), and 1RM were measured. Significant increase in V[Combining Dot Above]O2max from pretest to posttest was observed in the CT group (p = 0.010, effect size [ES] = 1.84) but not in the RT group (p = 0.559, ES = 0.35). Significant increase in CSA from pretest to posttest was observed in the RT group (p = 0.030, ES = 1.49) but not in the CT group (p = 0.110, ES = 1.01). Significant increase in 1RM from pretest to posttest was observed in the RT group (p = 0.021, ES = 1.57) but not in the CT group (p = 0.065, ES = 1.19). In conclusion, our data indicate that concurrent lower limb SIT interferes with arm muscle hypertrophy and strength.

A cross-sectional lower-body power profile of elite and subelite Australian football players.

PubMed

Caia, Johnpaul; Doyle, Tim L A; Benson, Amanda C

2013-10-01

Australian football (AF) is a sport which requires a vast array of physiological qualities, including high levels of strength and power. However, the power characteristics of AF players, particularly at the subelite level have not been extensively studied with further investigation warranted to understand the power capabilities and training requirements of elite and subelite AF groups. Therefore, the aim of this investigation was to develop a lower-body power profile of elite and subelite AF players. Eighteen elite and 12 subelite AF players completed a 1 repetition maximum (1RM) squat test to determine maximal lower-body strength, and countermovement jump (CMJ) and squat jump (SJ) testing to assess lower-body muscular power performance. Maximal lower-body strength was not statistically different between groups (p > 0.05). Elite players produced greater levels of peak power for CMJ at loads of 0, 30 (p < 0.05), and 40% (p < 0.01) of 1RM in comparison to subelite players. Squat jump peak power was statistically different between groups at 0, 20, 30, and 40% (p < 0.01) of 1RM; with elite players producing greater power than their subelite counterparts at all measured loads for SJ. Findings from this investigation demonstrate that elite AF players are able to generate greater levels of lower-body power than subelite AF players, despite no significant differences existing in maximal lower-body strength or body mass. As lower-body power levels clearly differentiate elite and subelite AF players, emphasis may be placed on improving the power levels of subelite players, particularly those aspiring to reach the elite level.

Effects of eccentric-focused and conventional resistance training on strength and functional capacity of older adults.

PubMed

Dias, Caroline Pieta; Toscan, Rafael; de Camargo, Mainara; Pereira, Evelyn Possobom; Griebler, Nathália; Baroni, Bruno Manfredini; Tiggemann, Carlos Leandro

2015-10-01

The aim of the study was to assess the effect of eccentric training using a constant load with longer exposure time at the eccentric phase on knee extensor muscle strength and functional capacity of elderly subjects in comparison with a conventional resistance training program. Twenty-six healthy elderly women (age = 67 ± 6 years) were randomly assigned to an eccentric-focused training group (ETG; n = 13) or a conventional training group (CTG; n = 13). Subjects underwent 12 weeks of resistance training twice a week. For the ETG, concentric and eccentric phases were performed using 1.5 and 4.5 s, respectively, while for CTG, each phase lasted 1.5 s. Maximum dynamic strength was assessed by the one-repetition maximum (1RM) test in the leg press and knee extension exercises, and for functional capacity, subjects performed specific tests (6-m walk test, timed up-and-go test, stair-climbing test, and chair-rising test). Both groups improved knee extension 1RM (24-26 %; p = 0.021), timed up-and-go test (11-16 %; p < 0.001), 6-m walk test (9-12 %; p = 0.004), stair-climbing test (8-13 %; p = 0.007), and chair-rising test (15-16 %; p < 0.001), but there was no significant difference between groups. In conclusion, the strategy of increasing the exposure time at the eccentric phase of movement using the same training volume and intensity does not promote different adaptations in strength or functional capacity compared to conventional resistance training in elderly woman.

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.

High intensity interval training does not impair strength gains in response to resistance training in premenopausal women.

PubMed

Gentil, Paulo; de Lira, Claudio Andre Barbosa; Filho, Suedi Gonçalves Cardoso; La Scala Teixeira, Cauê Vazquez; Steele, James; Fisher, James; Carneiro, Juliana Alves; Campos, Mário Hebling

2017-06-01

To compare the increases in upper- and lower-body muscle strength in premenopausal women performing resistance training (RT) alone or alongside concurrent high-intensity interval training (CT). Sixteen women (26-40 years) were randomly assigned into two groups that performed either RT or CT. Both groups performed the same RT program; however, CT performed additional high-intensity interval training (HIIT) on a bicycle ergometer before RT. The study lasted 8 weeks and the participants were tested for ten repetition maximum (10RM) load in elbow flexion (barbell biceps curl) and knee extension exercises pre- and post-intervention. RT was performed with 10-12 repetitions to self-determined repetition maximum in the first four weeks and then progressed to 8-10. During CT, HIIT was performed before RT with six 1-min bouts at 7-8 of perceived subjective exertion (RPE) and then progressed to eight bouts at 9-10 RPE. Analysis of variance revealed significant increases in upper and lower body strength for both the RT and CT groups. Biceps barbell curl 10RM load increased from 12.9 ± 3.2 kg to 14 ± 1.5 kg in CT (p < 0.05) and from 13 ± 1.8 kg to 15.9 ± 2.5 kg in RT (p < 0.05), with no significant between-groups differences. Knee extension 10RM increase from 31.9 ± 11.6 kg to 37.5 ± 8.5 kg for CT (p < 0.05) and from 30.6 ± 8.6 kg to 41.2 ± 7.4 kg for RT (p < 0.05). In conclusion, performing HIIT on a cycle ergometer before resistance training does not seem to impair muscle strength increases in the knee extensors or elbow flexors of pre-menopausal women. This information should be considered when prescribing exercise sessions, since both activities may be combined without negative effects in muscle strength.

Comparison of concentric and eccentric bench press repetitions to failure.

PubMed

Kelly, Stephen B; Brown, Lee E; Hooker, Steven P; Swan, Pamela D; Buman, Matthew P; Alvar, Brent A; Black, Laurie E

2015-04-01

Eccentric muscle actions (ECC) are characterized by muscle lengthening, despite actin-myosin crossbridge formation. Muscles acting eccentrically are capable of producing higher levels of force compared with muscles acting concentrically. The purpose of this study was to determine whether ECC bench press yields greater strength than concentric (CON) as determined by 1 repetition maximum (1RM). Additionally, a comparison was made examining differences in the number of repetitions to failure at different relative intensities of 1RM. Thirty healthy men (age = 24.63 ± 5.6 years) were tested for 1RM in CON and ECC bench press and the number of repetitions completed at 60, 70, 80, and 90% 1RM. For CON repetitions, the weight was mechanically lowered to the chest, and the participant pressed it up until the elbows were fully extended. The ECC bench press consisted of lowering a barbell from a fully extended elbow position to the chest in a continuous controlled manner for 3 seconds as determined by electronic metronome. Paired t-tests showed that ECC 1RM (115.99 ± 31.08 kg) was significantly (p ≤ 0.05) greater than CON 1RM (93.56 ± 26.56 kg), and the number of repetitions completed at 90% 1RM was significantly (p ≤ 0.05) greater in ECC (7.67 ± 3.24) as compared with CON (4.57 ± 2.21). There were no significant differences in number of completed repetitions during CON and ECC bench press at 60, 70, and 80% 1RM. These data indicate that ECC actions yield increased force capabilities (∼120%) as compared with CON in the bench press and may be less prone to fatigue, especially at higher intensities. These differences suggest a need to develop unique strategies for training eccentrically.

The Importance of Strength and Power on Key Performance Indicators in Elite Youth Soccer.

PubMed

Wing, Christopher E; Turner, Anthony N; Bishop, Chris J

2018-01-24

The purpose of this investigation was to examine the importance of strength and power in relation to key performance indicators (KPI's) within competitive soccer match play. This was achieved through using an experimental approach where fifteen subjects were recruited from a professional soccer club's scholarship squad during the 2013/14 season. Following anthropometric measures, power and strength were assessed across a range of tests which included the squat jump (SJ), countermovement jump (CMJ), 20 metre (m) sprint and arrowhead change of direction test. A predicted 1-repetition maximum (RM) was also obtained for strength by performing a 3RM test for both the back squat and bench press and a total score of athleticism (TSA) was provided by summing z-scores for all fitness tests together, providing one complete score for athleticism. Performance analysis data was collected during 16 matches for the following KPIs: passing, shooting, dribbling, tackling and heading. Alongside this, data concerning player ball involvements (touches) was recorded. Results showed that there was a significant correlation (p < 0.05) between CMJ (r = 0.80), SJ (r = 0.79) and TSA (r = 0.64) in relation to heading success. Similarly, a significant correlation (p < 0.05) between predicted 1RM squat strength and tackle success (r = 0.61). These data supports the notion that strength and power training are important to soccer performance, particularly when players are required to win duels of a physical nature. There were no other relationships found between the fitness data and the KPI's recorded during match play which may indicate that other aspects of player's development such as technical skill, cognitive function and sensory awareness are more important for soccer-specific performance.

Validity of a Commercial Linear Encoder to Estimate Bench Press 1 RM from the Force-Velocity Relationship.

PubMed

Bosquet, Laurent; Porta-Benache, Jeremy; Blais, Jérôme

2010-01-01

The aim of this study was to assess the validity and accuracy of a commercial linear encoder (Musclelab, Ergotest, Norway) to estimate Bench press 1 repetition maximum (1RM) from the force - velocity relationship. Twenty seven physical education students and teachers (5 women and 22 men) with a heterogeneous history of strength training participated in this study. They performed a 1 RM test and a force - velocity test using a Bench press lifting task in a random order. Mean 1 RM was 61.8 ± 15.3 kg (range: 34 to 100 kg), while 1 RM estimated by the Musclelab's software from the force-velocity relationship was 56.4 ± 14.0 kg (range: 33 to 91 kg). Actual and estimated 1 RM were very highly correlated (r = 0.93, p<0.001) but largely different (Bias: 5.4 ± 5.7 kg, p < 0.001, ES = 1.37). The 95% limits of agreement were ±11.2 kg, which represented ±18% of actual 1 RM. It was concluded that 1 RM estimated from the force-velocity relationship was a good measure for monitoring training induced adaptations, but also that it was not accurate enough to prescribe training intensities. Additional studies are required to determine whether accuracy is affected by age, sex or initial level. Key pointsSome commercial devices allow to estimate 1 RM from the force-velocity relationship.These estimations are valid. However, their accuracy is not high enough to be of practical help for training intensity prescription.Day-to-day reliability of force and velocity measured by the linear encoder has been shown to be very high, but the specific reliability of 1 RM estimated from the force-velocity relationship has to be determined before concluding to the usefulness of this approach in the monitoring of training induced adaptations.

Validity of a Commercial Linear Encoder to Estimate Bench Press 1 RM from the Force-Velocity Relationship

PubMed Central

Bosquet, Laurent; Porta-Benache, Jeremy; Blais, Jérôme

2010-01-01

The aim of this study was to assess the validity and accuracy of a commercial linear encoder (Musclelab, Ergotest, Norway) to estimate Bench press 1 repetition maximum (1RM) from the force - velocity relationship. Twenty seven physical education students and teachers (5 women and 22 men) with a heterogeneous history of strength training participated in this study. They performed a 1 RM test and a force - velocity test using a Bench press lifting task in a random order. Mean 1 RM was 61.8 ± 15.3 kg (range: 34 to 100 kg), while 1 RM estimated by the Musclelab’s software from the force-velocity relationship was 56.4 ± 14.0 kg (range: 33 to 91 kg). Actual and estimated 1 RM were very highly correlated (r = 0.93, p<0.001) but largely different (Bias: 5.4 ± 5.7 kg, p < 0.001, ES = 1.37). The 95% limits of agreement were ±11.2 kg, which represented ±18% of actual 1 RM. It was concluded that 1 RM estimated from the force-velocity relationship was a good measure for monitoring training induced adaptations, but also that it was not accurate enough to prescribe training intensities. Additional studies are required to determine whether accuracy is affected by age, sex or initial level. Key points Some commercial devices allow to estimate 1 RM from the force-velocity relationship. These estimations are valid. However, their accuracy is not high enough to be of practical help for training intensity prescription. Day-to-day reliability of force and velocity measured by the linear encoder has been shown to be very high, but the specific reliability of 1 RM estimated from the force-velocity relationship has to be determined before concluding to the usefulness of this approach in the monitoring of training induced adaptations. PMID:24149641

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.

Deconstructing the power resistance relationship for squats: A joint-level analysis.

PubMed

Farris, D J; Lichtwark, G A; Brown, N A T; Cresswell, A G

2016-07-01

Generating high leg power outputs is important for executing rapid movements. Squats are commonly used to increase leg strength and power. Therefore, it is useful to understand factors affecting power output in squatting. We aimed to deconstruct the mechanisms behind why power is maximized at certain resistances in squatting. Ten male rowers (age = 20 ± 2.2 years; height = 1.82 ± 0.03 m; mass = 86 ± 11 kg) performed maximal power squats with resistances ranging from body weight to 80% of their one repetition maximum (1RM). Three-dimensional kinematics was combined with ground reaction force (GRF) data in an inverse dynamics analysis to calculate leg joint moments and powers. System center of mass (COM) velocity and power were computed from GRF data. COM power was maximized across a range of resistances from 40% to 60% 1RM. This range was identified because a trade-off in hip and knee joint powers existed across this range, with maximal knee joint power occurring at 40% 1RM and maximal hip joint power at 60% 1RM. A non-linear system force-velocity relationship was observed that dictated large reductions in COM power below 20% 1RM and above 60% 1RM. These reductions were due to constraints on the control of the movement. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Respiratory muscle adaptations: a comparison between bodybuilders and endurance athletes.

PubMed

Hackett, D A; Johnson, N; Chow, C

2013-04-01

The purpose of this study was to compare the respiratory muscle and lung function measures of bodybuilders (BB) and endurance athletes (EA). Forty-two male subjects (22 BB and 20 EA) aged 20-35 years underwent respiratory muscle strength measurements (MIP and MEP), lung function testing (FEV1, FVC, FEV1/FVC%, IC, ERV, FRC, RV, and TLC), hydrostatic weighing and VO2max testing. One-repetition maximum (1RM) for bench press, squat and deadlift was performed by BB. BB had significantly greater MIP and MEP compared to EA by 43% and 53% respectively (P<0.01). Moderate correlation was found for MEP and 1RM bench press (P<0.01), and weak correlations found for the squat and deadlift (P<0.01). Fat-free mass was significantly greater for BB compared with EA (P<0.01), while VO2max was significantly greater for EA compared with BB (P<0.01). No differences in lung function indices were observed between groups. When compared to EA, BB exhibited significantly greater respiratory muscle strength. The maximal load lifted for bench press predicted expiratory muscle strength gain. Lung function measures did not differ between the groups.

Maximal intended velocity training induces greater gains in bench press performance than deliberately slower half-velocity training.

PubMed

González-Badillo, Juan José; Rodríguez-Rosell, David; Sánchez-Medina, Luis; Gorostiaga, Esteban M; Pareja-Blanco, Fernando

2014-01-01

The purpose of this study was to compare the effect on strength gains of two isoinertial resistance training (RT) programmes that only differed in actual concentric velocity: maximal (MaxV) vs. half-maximal (HalfV) velocity. Twenty participants were assigned to a MaxV (n = 9) or HalfV (n = 11) group and trained 3 times per week during 6 weeks using the bench press (BP). Repetition velocity was controlled using a linear velocity transducer. A complementary study (n = 10) aimed to analyse whether the acute metabolic (blood lactate and ammonia) and mechanical response (velocity loss) was different between the MaxV and HalfV protocols used. Both groups improved strength performance from pre- to post-training, but MaxV resulted in significantly greater gains than HalfV in all variables analysed: one-repetition maximum (1RM) strength (18.2 vs. 9.7%), velocity developed against all (20.8 vs. 10.0%), light (11.5 vs. 4.5%) and heavy (36.2 vs. 17.3%) loads common to pre- and post-tests. Light and heavy loads were identified with those moved faster or slower than 0.80 m · s(-1) (∼ 60% 1RM in BP). Lactate tended to be significantly higher for MaxV vs. HalfV, with no differences observed for ammonia which was within resting values. Both groups obtained the greatest improvements at the training velocities (≤ 0.80 m · s(-1)). Movement velocity can be considered a fundamental component of RT intensity, since, for a given %1RM, the velocity at which loads are lifted largely determines the resulting training effect. BP strength gains can be maximised when repetitions are performed at maximal intended velocity.

Different Levels of Eccentric Resistance during Eight Weeks of Training Affect Muscle Strength and Lean Tissue Mass

NASA Technical Reports Server (NTRS)

English, K. L.; Loehr, J. A.; Lee, S. M. C.; Laughlin, M. S.; Hagan, R. D.

2008-01-01

Coupling concentric and eccentric muscle contractions appears to be important in the development of muscle strength and hypertrophy. The interim Resistive Exercise Device (iRED) currently used aboard the International Space Station does not seem to be as effective as free weight training in ambulatory subjects and has not completely protected against muscular deconditioning due to space flight. The lack of protection during space flight could be caused by iRED's proportionally lower eccentric resistance (60-70%) compared to concentric resistance. PURPOSE: To determine the effects of 8 wks of lower body resistive exercise training using five levels of eccentric resistance on muscle strength and lean tissue mass. METHODS: Forty untrained males (34.9 +/- 7 yrs, 80.9 +/- 9.8 kg, 178.2 +/- 7.1 cm; mean +/- SD) completed three 1-repetition maximum (1-RM) strength tests for both the supine leg press (LP) and supine heel raise (HR) prior to training; subjects were matched for LP strength and randomly assigned to one of five training groups. Concentric load (% 1-RM) was constant across groups during training, but each group trained with different levels of eccentric load (0%, 33%, 66%, 100%, or 138% of concentric). Subjects trained 3 d / wk for 8 wks using a periodized program for LP and HR based on percentages of the highest pre-training 1-RM. LP and HR 1-RM and leg lean mass (LLM; assessed by DEXA) were measured pre- and post-training. A two-way ANOVA was used to analyze all dependent measures. Tukey's post hoc tests were used to test significant main effects. Within group pre- to post-training changes were compared using paired t-tests with a Bonferroni adjustment. Statistical significance was set a priori at p 0.05. All data are expressed as mean +/- SE. RESULTS: LP 1-RM strength increased significantly in all groups pre- to post-training. The 138% group increase (20.1 +/- 3.7%) was significantly greater than the 0% (7.9 +/- 2.8%), 33% (7.7 +/- 4.6%), and 66% (7.5 +/- 4.3%) groups. All groups significantly increased HR strength pre- to posttraining (33%: 7.5 +/- 6.1%; 66%: 6.6 +/- 3.7%; 100%: 12.2 +/- 1.8%; 138%: 11.0 +/- 6.4%) except for the 0% (4.9 +/- 9.1%) group. There were no differences between groups. LLM increased significantly pre- to post-training in only the 138% group; there were no differences between groups. CONCLUSIONS: Eight wks of lower body resistive exercise training with eccentric overload resulted in greater increases in LP strength than training with eccentric loads of 66% or less. Post-training HR strength was not affected by eccentric training load, perhaps because of the predominance of Type I fibers typical in the gastrocnemius. Only 138% eccentric training significantly increased LLM. PRACTICAL APPLICATIONS: For athletes or others desiring to maximize muscle strength and hypertrophy gains, training with eccentric loads greater than 100% of concentric resistance will provide greater increases in muscle strength and lean tissue mass in some muscle groups. In a rehabilitation or geriatric exercise setting that places primary emphasis on program adherence and moderate strength gains, training with an eccentric underload may provide strength increases comparable to those of traditional 1:1 training but with less muscle soreness and physiologic insult to the patient, but this has yet to be proven.

Differential Effects of Heavy Versus Moderate Loads on Measures of Strength and Hypertrophy in Resistance-Trained Men.

PubMed

Schoenfeld, Brad J; Contreras, Bret; Vigotsky, Andrew D; Peterson, Mark

2016-12-01

The purpose of the present study was to evaluate muscular adaptations between heavy- and moderate-load resistance training (RT) with all other variables controlled between conditions. Nineteen resistance-trained men were randomly assigned to either a strength-type RT routine (HEAVY) that trained in a loading range of 2-4 repetitions per set (n = 10) or a hypertrophy-type RT routine (MODERATE) that trained in a loading range of 8-12 repetitions per set (n = 9). Training was carried out 3 days a week for 8 weeks. Both groups performed 3 sets of 7 exercises for the major muscle groups of the upper and lower body. Subjects were tested pre- and post-study for: 1 repetition maximum (RM) strength in the bench press and squat, upper body muscle endurance, and muscle thickness of the elbow flexors, elbow extensors, and lateral thigh. Results showed statistically greater increases in 1RM squat strength favoring HEAVY compared to MODERATE. Alternatively, statistically greater increases in lateral thigh muscle thickness were noted for MODERATE versus HEAVY. These findings indicate that heavy load training is superior for maximal strength goals while moderate load training is more suited to hypertrophy-related goals when an equal number of sets are performed between conditions.

The effect of sprinting after each set of heavy resistance training on the running speed and jumping performance of young basketball players.

PubMed

Tsimahidis, Konstantinos; Galazoulas, Christos; Skoufas, Dimitrios; Papaiakovou, Georgios; Bassa, Eleni; Patikas, Dimitrios; Kotzamanidis, Christos

2010-08-01

The purpose of this study was to investigate the effect of a 10-week heavy resistance combined with a running training program on the strength, running speed (RS), and vertical jump performance of young basketball players. Twenty-six junior basketball players were equally divided in 2 groups. The control (CON) group performed only technical preparation and the group that followed the combined training program (CTP) performed additionally 5 sets of 8-5 repetition maximum (RM) half squat with 1 30-m sprint after each set. The evaluation took place before training and after the 5th and 10th weeks of training. Apart from the 1RM half squat test, the 10- and 30-m running time was measured using photocells and the jump height (squat, countermovement jump, and drop jump) was estimated taking into account the flight time. The 1RM increased by 30.3 +/- 1.5% at the 10th week of training for the CTP group (p < 0.05), whereas the CON group showed no significant increase (1.1 +/- 1.6%, p > 0.05). In general, all measured parameters showed a statistically significant increase after the 5th and 10th weeks (p < 0.05), in contrast to the CON group (p > 0.05). This suggests that the applied CTP is beneficial for the strength, RS, and jump height of young basketball players. The observed adaptations in the CTP group could be attributed to learning factors and to a more optimal transfer of the strength gain to running and jumping performance.

Test-retest reliability of barbell velocity during the free-weight bench-press exercise.

PubMed

Stock, Matt S; Beck, Travis W; DeFreitas, Jason M; Dillon, Michael A

2011-01-01

The purpose of this study was to calculate test-retest reliability statistics for peak barbell velocity during the free-weight bench-press exercise for loads corresponding to 10-90% of the 1-repetition maximum (1RM). Twenty-one healthy, resistance-trained men (mean ± SD age = 23.5 ± 2.7 years; body mass = 90.5 ± 14.6 kg; 1RM bench press = 125.4 ± 18.4 kg) volunteered for this study. A minimum of 48 hours after a maximal strength testing and familiarization session, the subjects performed single repetitions of the free-weight bench-press exercise at each tenth percentile (10-90%) of the 1RM on 2 separate occasions. For each repetition, the subjects were instructed to press the barbell as rapidly as possible, and peak barbell velocity was measured with a Tendo Weightlifting Analyzer. The test-retest intraclass correlation coefficients (model 2,1) and corresponding standard errors of measurement (expressed as percentages of the mean barbell velocity values) were 0.717 (4.2%), 0.572 (5.0%), 0.805 (3.1%), 0.669 (4.7%), 0.790 (4.6%), 0.785 (4.8%), 0.811 (5.8%), 0.714 (10.3%), and 0.594 (12.6%) for the weights corresponding to 10-90% 1RM. There were no mean differences between the barbell velocity values from trials 1 and 2. These results indicated moderate to high test-retest reliability for barbell velocity from 10 to 70% 1RM but decreased consistency at 80 and 90% 1RM. When examining barbell velocity during the free-weight bench-press exercise, greater measurement error must be overcome at 80 and 90% 1RM to be confident that an observed change is meaningful.

Fitness Level Modulates Intraocular Pressure Responses to Strength Exercises.

PubMed

Vera, Jesús; Jiménez, Raimundo; Redondo, Beatríz; Cárdenas, David; García-Ramos, Amador

2018-06-01

Purpose/Aim: The execution of strength exercises has demonstrated to increase the intraocular pressure (IOP) levels, and it may have a negative impact on the ocular health. We aimed to explore the influence of fitness level on the acute IOP response to strength exercises performed under different loading conditions, as well as to test whether the IOP responses differ between the bench press and jump squat when performed against the same relative loads. Forty military personnel males were divided in two subgroups (20 high-fit and 20 low-fit) based on their relative to body mass one-repetition maximum (1-RM). Participants performed an incremental loading test in the bench press and jump squat exercises, and IOP was assessed before and after each repetition by rebound tonometry. IOP increased immediately after executing both exercises (p < 0.01 in both cases), being the magnitude of the IOP increment positively and linearly associated with the increment of the load in both groups (i.e., high-fit and low-fit) and in both exercises (R 2 range: 0.81-1.00). Higher fitness level attenuated the IOP rise produced by both exercises (p < 0.01 in both cases). The bench press induced higher IOP increments than the jump squat for both groups at relative loads of ~50%1-RM and ~60%1-RM (p < 0.01 in all cases). These data indicate that IOP increases as a consequence of performing strength exercises, being the increment accentuated with the increase of the load and in the bench press compared to the jump squat exercise. Of special importance would be that the IOP responses were significantly reduced in high-fit individuals. These findings should be addressed in glaucoma patients.

Low level laser therapy associated with a strength training program on muscle performance in elderly women: a randomized double blind control study.

PubMed

Toma, Renata Luri; Vassão, Patrícia Gabrielli; Assis, Livia; Antunes, Hanna Karen Moreira; Renno, Ana Claudia Muniz

2016-08-01

The aging process leads to a gradual loss of muscle mass and muscle performance, leading to a higher functional dependence. Within this context, many studies have demonstrated the benefits of a combination of physical exercise and low level laser therapy (LLLT) as an intervention that enhances muscle performance in young people and athletes. The aim of this study was to evaluate the effects of combination of LLLT and strength training on muscle performance in elderly women. For this, a hundred elderly women were screened, and 48 met all inclusion criteria to participate in this double-blind placebo-controlled trial. Volunteers were divided in three groups: control (CG = 15), strength training associated with placebo LLLT (TG = 17), and strength training associated with active LLLT (808 nm, 100 mW, 7 J) (TLG = 16). The strength training consisted of knee flexion-extension performed with 80 % of 1-repetition maximum (1-RM) during 8 weeks. Several outcomes related to muscle performance were analyzed through the 6-min walk test (6-MWT), isokinetic dynamometry, surface electromyography (SEMG), lactate concentration, and 1-RM. The results revealed that a higher work (p = 0.0162), peak torque (p = 0.0309), and power (p = 0.0223) were observed in TLG compared to CG. Furthermore, both trained groups increased the 1-RM load (TG vs CG: p = 0.0067 and TLG vs CG: p < 0.0001) and decreased the lactate concentration in the third minute after isokinetic protocol (CG vs TLG: p = 0.0289 and CG vs TG: p = 0.0085). No difference in 6-MWT and in fatigue levels were observed among the groups. The present findings suggested that LLLT in combination with strength training was able to improve muscle performance in elderly people.

Effect of a submaximal half-squats warm-up program on vertical jumping ability.

PubMed

Gourgoulis, Vassilios; Aggeloussis, Nickos; Kasimatis, Panagiotis; Mavromatis, Giorgos; Garas, Athanasios

2003-05-01

The purpose of the current research was to study the effect of a warm-up program including submaximal half-squats on vertical jumping ability. Twenty physically active men participated in the study. Each subject performed 5 sets of half-squats with 2 repetitions at each of the following intensities: 20, 40, 60, 80, and 90% of the 1 repetition maximum (1RM) load. Prior to the first set and immediately after the end of the last set, the subjects performed 2 countermovement jumps on a Kistler force platform; the primary goal was to jump as high as possible. The results showed that mean vertical jumping ability improved by 2.39% after the warm-up period. Subjects were then divided into 2 groups according to their 1RM values for the half-squat. Subjects with greater maximal strength ability improved their vertical jumping ability (4.01%) more than did subjects with lower maximal strength (0.42%). A warm-up protocol including half-squats with submaximal loads and explosive execution can be used for short-term improvements of vertical jumping performance, and this effect is greater in athletes with a relatively high strength ability.

Muscular strength is associated with self-esteem in college men but not women.

PubMed

Ciccolo, Joseph T; SantaBarbara, Nicholas J; Dunsiger, Shira I; Busch, Andrew M; Bartholomew, John B

2016-12-01

Muscular strength is a well-known predictor of morbidity and mortality. Similarly, self-esteem is a predictor of health and well-being. The relationship between these two variables, however, is currently unknown. This study examined the cross-sectional relationship between maximal muscular strength (i.e. handgrip and one-repetition-maximum (1-RM) squat) and global self-esteem in 126 college students. Significant correlations were found between both measures of muscular strength and self-esteem. Further analyses revealed that these relationships were only significant for men. Based on these results, additional research is needed to further explore the relationship between muscular strength and self-esteem, especially in other demographic groups and longitudinally. © The Author(s) 2015.

Effects of an afterschool community center physical activity program on fitness and body composition in obese youth.

PubMed

Crouter, Scott E; Salas, Carlos; Wiecha, Jean

2017-06-01

Physical activity (PA) promotes health in obese youth and is an important adjunct to medical weight management. Access to structured fitness programmes for obese, low-income youth is limited and potential benefits of such programmes are poorly understood. We describe an urban afterschool fitness programme for obese youth and participants' changes in fitness and body composition. A case series of 30 youth (age: 11.5 ± 2.5 years) with BMI ≥95th percentile and physician referral received a 24-wk programme scholarship. The programme, offered 4 times a week for 90-min.session, included aerobic, strength, and self-organised PA. Primary outcomes, measured at baseline (BL) time 1 (4-8 wk) and time 2 (12-16 wk) were BMI, per cent body fat (%BF), fat-free mass (FFM), heart rate during a treadmill test, and muscular strength (one repetition maximum (1RM)) and endurance (reps at 70% of 1RM) on the leg press (LP) and chest press (CP). Average participation was 1.5 ± 0.6 visits per week for 18.7 ± 6.5 weeks. Between BL and time 2, LP and CP 1RM and endurance significantly improved (P < 0.05). Additionally, there was a significant interaction for %BF with boys losing 5.2% (P > 0.05) while girls lost 0% (>0.05). Obese youth attending an urban fitness programme for at least three months improved strength and body composition, but average attendance was below planned levels.

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.

RPE and Velocity Relationships for the Back Squat, Bench Press, and Deadlift in Powerlifters.

PubMed

Helms, Eric R; Storey, Adam; Cross, Matt R; Brown, Scott R; Lenetsky, Seth; Ramsay, Hamish; Dillen, Carolina; Zourdos, Michael C

2017-02-01

Helms, ER, Storey, A, Cross, MR, Browm, SR, Lenetsky, S, Ramsay, H, Dillen, C, and Zourdos, MC. RPE and velocity relationships for the back squat, bench press, and deadlift in powerlifters. J Strength Cond Res 31(2): 292-297, 2017-The purpose of this study was to compare average concentric velocity (ACV) and rating of perceived exertion (RPE) based on repetitions in reserve on the squat, bench press, and deadlift. Fifteen powerlifters (3 women and 12 men, mean age 28.4 ± 8.5 years) worked up to a one repetition maximum (1RM) on each lift. Rating of perceived exertion was recorded on all sets, and the ACV was recorded for all sets performed at 80% of estimated 1RM and higher, up to 1RM. Rating of perceived exertion at 1RM on squat, bench press, and deadlift was 9.6 ± 0.5, 9.7 ± 0.4, and 9.6 ± 0.5, respectively and was not significantly different (p > 0.05). The ACV at 1RM on squat, bench press and deadlift was 0.23 ± 0.05, 0.10 ± 0.04, and 0.14 ± 0.05 m·second, respectively. Squat was faster than both bench press and deadlift (p > 0.001), and deadlift was faster than bench press (p = 0.05). Very strong relationships (r = 0.88-0.91) between percentage 1RM and RPE were observed on each lift. The ACV showed strong (r = -0.79 to -0.87) and very strong (r = -0.90 to 92) inverse relationships with RPE and percentage 1RM on each lift, respectively. We conclude that RPE may be a useful tool for prescribing intensity for squat, bench press, and deadlift in powerlifters, in addition to traditional methods such as percentage of 1RM. Despite high correlations between percentage 1RM and ACV, a "velocity load profile" should be developed to prescribe intensity on an individual basis with appropriate accuracy.

Moderate volume of high relative training intensity produces greater strength gains compared with low and high volumes in competitive weightlifters.

PubMed

González-Badillo, Juan José; Izquierdo, Mikel; Gorostiaga, Esteban M

2006-02-01

The purpose of this study was to examine the effect of 3 volumes of heavy resistance, average relative training intensity (expressed as a percentage of 1 repetition maximum that represented the absolute kilograms lifted divided by the number of repetitions performed) programs on maximal strength (1RM) in Snatch (Sn), Clean & Jerk (C&J), and Squat (Sq). Twenty-nine experienced (>3 years), trained junior weightlifters were randomly assigned into 1 of 3 groups: low-intensity group (LIG; n = 12), moderate-intensity group (MIG; n = 9), and high-intensity group (HIG; n = 8). All subjects trained for 10 weeks, 4-5 days a week, in a periodized routine using the same exercises and training volume (expressed as total number of repetitions performed at intensities equal to or greater than 60% of 1RM), but different programmed total repetitions at intensities of >90-100% of 1RM for the entire 10-week period: LIG (46 repetitions), MIG (93 repetitions), and HIG (184 repetitions). During the training period, MIG and LIG showed a significant increase (p < 0.01-0.05) for C&J (10.5% and 3% for MIG and LIG, respectively) and Sq (9.5% and 5.3% for MIG and LIG, respectively), whereas in HIG the increase took place only in Sq (6.9%, p < 0.05). A calculation of effect sizes revealed greater strength gains in the MIG than in HIG or LIG. There were no significant differences between LIG and HIG training volume-induced strength gains. All the subjects in HIG were unable to fully accomplish the repetitions programmed at relative intensities greater than 90% of 1RM. The present results indicate that short-term resistance training using moderate volumes of high relative intensity tended to produce higher enhancements in weightlifting performance compared with low and high volumes of high relative training intensities of equal total volume in experienced, trained young weightlifters. Therefore, for the present population of weightlifters, it may be beneficial to use the MIG training protocol to improve the weightlifting program at least in a short-term (10 weeks) cycle of training.

Training for Power and Speed: Effects of Increasing or Decreasing Jump Squat Velocity in Elite Young Soccer Players.

PubMed

Loturco, Irineu; Nakamura, Fabio Y; Kobal, Ronaldo; Gil, Saulo; Abad, César C Cal; Cuniyochi, Rogério; Pereira, Lucas A; Roschel, Hamilton

2015-10-01

The aim of this study was to test the effects of 2 different velocity-oriented power training regimens by either increasing or decreasing the jump squat velocity during jump training sessions applied 3 times a week for 6 weeks in soccer players. Twenty-four elite under-20 soccer players were randomly assigned to an increased bar velocity group (IVG) or a reduced bar velocity group (RVG). Athletes had their countermovement jump heights, mean propulsive velocities (MPVs) in jump squat, leg press maximum dynamic strength (1 repetition maximum [RM]), 20-m sprint times, and zig-zag change of direction (COD) abilities assessed before and after the intervention. Performance in all tests improved after training in both groups. However, greater gains in 1RM and MPV using 50-90% of body mass (BM) were noted for the RVG. The IVG demonstrated greater improvements in speed at 5, 10, and 20 m and MPV with no additional external load and with 40% BM. Both groups improved similarly in countermovement jumps and COD. To conclude, both velocity-oriented power training regimens were effective in eliciting neuromechanical adaptations, leading to better strength/power/speed performances, and the choice as to the most suitable method should be tailored according to players' needs/deficiencies.

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.

The Influence of Resistance Training Experience on the Between-Day Reliability of Commonly Used Strength Measures in Male Youth Athletes.

PubMed

Weakley, Jonathon J S; Till, Kevin; Darrall-Jones, Joshua; Roe, Gregory A B; Phibbs, Padraic J; Read, Dale B; Jones, Ben L

2017-07-01

Weakley, JJS, Till, K, Darrall-Jones, J, Roe, GAB, Phibbs, PJ, Read, DB, and Jones, BL. The influence of resistance training experience on the between-day reliability of commonly used strength measures in male youth athletes. J Strength Cond Res 31(7): 2005-2010, 2017-The purpose of this study was to determine the between-day reliability of commonly used strength measures in male youth athletes while considering resistance training experience. Data were collected on 25 male athletes over 2 testing sessions, with 72 hours rest between, for the 3 repetition maximum (3RM) front squat, chin-up, and bench press. Subjects were initially categorized by resistance training experience (inexperienced; 6-12 months, experienced; >2 years). The assessment of the between-day reliability (coefficient of variation [CV%]) showed that the front squat (experienced: 2.90%; inexperienced: 1.90%), chin-up (experienced: 1.70%; inexperienced: 1.90%), and bench press (experienced: 4.50%; inexperienced: 2.40%) were all reliable measures of strength in both groups. Comparison between groups for the error of measurement for each exercise showed trivial differences. When both groups were combined, the CV% for the front squat, bench press, and chin-up were 2.50, 1.80, and 3.70%, respectively. This study provides scientists and practitioners with the between-day reliability reference data to determine real and practical changes for strength in male youth athletes with different resistance training experience. Furthermore, this study demonstrates that 3RM front squat, chin-up, and bench press are reliable exercises to quantify strength in male youth athletes.

1RM prediction: a novel methodology based on the force-velocity and load-velocity relationships.

PubMed

Picerno, Pietro; Iannetta, Danilo; Comotto, Stefania; Donati, Marco; Pecoraro, Fabrizio; Zok, Mounir; Tollis, Giorgio; Figura, Marco; Varalda, Carlo; Di Muzio, Davide; Patrizio, Federica; Piacentini, Maria Francesca

2016-10-01

This study aimed to evaluate the accuracy of a novel approach for predicting the one-repetition maximum (1RM). The prediction is based on the force-velocity and load-velocity relationships determined from measured force and velocity data collected during resistance-training exercises with incremental submaximal loads. 1RM was determined as the load corresponding to the intersection of these two curves, where the gravitational force exceeds the force that the subject can exert. The proposed force-velocity-based method (FVM) was tested on 37 participants (23.9 ± 3.1 year; BMI 23.44 ± 2.45) with no specific resistance-training experience, and the predicted 1RM was compared to that achieved using a direct method (DM) in chest-press (CP) and leg-press (LP) exercises. The mean 1RM in CP was 99.5 kg (±27.0) for DM and 100.8 kg (±27.2) for FVM (SEE = 1.2 kg), whereas the mean 1RM in LP was 249.3 kg (±60.2) for DM and 251.1 kg (±60.3) for FVM (SEE = 2.1 kg). A high correlation was found between the two methods for both CP and LP exercises (0.999, p < 0.001). Good agreement between the two methods emerged from the Bland and Altman plot analysis. These findings suggest the use of the proposed methodology as a valid alternative to other indirect approaches for 1RM prediction. The mathematical construct is simply based on the definition of the 1RM, and it is fed with subject's muscle strength capacities measured during a specific exercise. Its reliability is, thus, expected to be not affected by those factors that typically jeopardize regression-based approaches.

Muscular adaptations in low- versus high-load resistance training: A meta-analysis.

PubMed

Schoenfeld, Brad J; Wilson, Jacob M; Lowery, Ryan P; Krieger, James W

2016-01-01

There has been much debate as to optimal loading strategies for maximising the adaptive response to resistance exercise. The purpose of this paper therefore was to conduct a meta-analysis of randomised controlled trials to compare the effects of low-load (≤60% 1 repetition maximum [RM]) versus high-load (≥65% 1 RM) training in enhancing post-exercise muscular adaptations. The strength analysis comprised 251 subjects and 32 effect sizes (ESs), nested within 20 treatment groups and 9 studies. The hypertrophy analysis comprised 191 subjects and 34 ESs, nested with 17 treatment groups and 8 studies. There was a trend for strength outcomes to be greater with high loads compared to low loads (difference = 1.07 ± 0.60; CI: -0.18, 2.32; p = 0.09). The mean ES for low loads was 1.23 ± 0.43 (CI: 0.32, 2.13). The mean ES for high loads was 2.30 ± 0.43 (CI: 1.41, 3.19). There was a trend for hypertrophy outcomes to be greater with high loads compared to low loads (difference = 0.43 ± 0.24; CI: -0.05, 0.92; p = 0.076). The mean ES for low loads was 0.39 ± 0.17 (CI: 0.05, 0.73). The mean ES for high loads was 0.82 ± 0.17 (CI: 0.49, 1.16). In conclusion, training with loads ≤50% 1 RM was found to promote substantial increases in muscle strength and hypertrophy in untrained individuals, but a trend was noted for superiority of heavy loading with respect to these outcome measures with null findings likely attributed to a relatively small number of studies on the topic.

Greater Strength Gains after Training with Accentuated Eccentric than Traditional Isoinertial Loads in Already Strength-Trained Men

PubMed Central

Walker, Simon; Blazevich, Anthony J.; Haff, G. Gregory; Tufano, James J.; Newton, Robert U.; Häkkinen, Keijo

2016-01-01

As training experience increases it becomes more challenging to induce further neuromuscular adaptation. Consequently, strength trainers seek alternative training methods in order to further increase strength and muscle mass. One method is to utilize accentuated eccentric loading, which applies a greater external load during the eccentric phase of the lift as compared to the concentric phase. Based upon this practice, the purpose of this study was to determine the effects of 10 weeks of accentuated eccentric loading vs. traditional isoinertial resistance training in strength-trained men. Young (22 ± 3 years, 177 ± 6 cm, 76 ± 10 kg, n = 28) strength-trained men (2.6 ± 2.2 years experience) were allocated to concentric-eccentric resistance training in the form of accentuated eccentric load (eccentric load = concentric load + 40%) or traditional resistance training, while the control group continued their normal unsupervised training program. Both intervention groups performed three sets of 6-RM (session 1) and three sets of 10-RM (session 2) bilateral leg press and unilateral knee extension exercises per week. Maximum force production was measured by unilateral isometric (110° knee angle) and isokinetic (concentric and eccentric 30°.s−1) knee extension tests, and work capacity was measured by a knee extension repetition-to-failure test. Muscle mass was assessed using panoramic ultrasonography and dual-energy x-ray absorptiometry. Surface electromyogram amplitude normalized to maximum M-wave and the twitch interpolation technique were used to examine maximal muscle activation. After training, maximum isometric torque increased significantly more in the accentuated eccentric load group than control (18 ± 10 vs. 1 ± 5%, p < 0.01), which was accompanied by an increase in voluntary activation (3.5 ± 5%, p < 0.05). Isokinetic eccentric torque increased significantly after accentuated eccentric load training only (10 ± 9%, p < 0.05), whereas concentric torque increased equally in both the accentuated eccentric load (10 ± 9%, p < 0.01) and traditional (9 ± 6%, p < 0.01) resistance training groups; however, the increase in the accentuated eccentric load group was significantly greater (p < 0.05) than control (1 ± 7%). Knee extension repetition-to-failure improved in the accentuated eccentric load group only (28%, p < 0.05). Similar increases in muscle mass occurred in both intervention groups. In summary, accentuated eccentric load training led to greater increases in maximum force production, work capacity and muscle activation, but not muscle hypertrophy, in strength-trained individuals. PMID:27199764

A comparison of maximal squat strength and 5-, 10-, and 20-meter sprint times, in athletes and recreationally trained men.

PubMed

Comfort, Paul; Bullock, Nathan; Pearson, Stephen J

2012-04-01

The purpose of this study was to identify whether there was a relationship between relative strength during a 1 repetition maximum (1RM) back squat and 5-, 10-, and 20-m sprint performances in both trained athletes and recreationally trained individuals. Professional rugby league players (n = 24) and recreationally trained individuals (n = 20) participated in this investigation. Twenty-meter sprint time and 1RM back squat strength, using free weights, were assessed on different days. There were no significant (p ≥ 0.05) differences between the well-trained and recreationally trained groups for 5-m sprint times. In contrast, the well-trained group's 10- and 20-m sprint times were significantly quicker (p = 0.004; p = 0.002) (1.78 + 0.06 seconds; 3.03 + 0.09 seconds) compared with the recreationally trained group (1.84 + 0.07 seconds; 3.13 + 0.11 seconds). The athletes were significantly stronger (170.63 + 21.43 kg) than the recreationally trained individuals (135.45 + 30.07 kg) (p = 0.01); however, there were no significant differences (p > 0.05) in relative strength between groups (1.78 + 0.27 kg/kg; 1.78 + 0.33 kg/kg, respectively). Significant negative correlations were found between 5-m sprint time and relative squat strength (r = -0.613, power = 0.96, p = 0.004) and between relative squat strength and 10- and 20-m sprint times in the recreationally trained group (r = -0.621, power = 0.51, p = 0.003; r = -0.604, power = 0.53, p = 0.005, respectively). These results, indicating that relative strength, are important for initial sprint acceleration in all athletes but more strongly related to sprint performance over greater distances in recreationally trained individuals.

Validity of one-repetition maximum predictive equations in men with spinal cord injury.

PubMed

Ribeiro Neto, F; Guanais, P; Dornelas, E; Coutinho, A C B; Costa, R R G

2017-10-01

Cross-sectional study. The study aimed (a) to test the cross-validation of current one-repetition maximum (1RM) predictive equations in men with spinal cord injury (SCI); (b) to compare the current 1RM predictive equations to a newly developed equation based on the 4- to 12-repetition maximum test (4-12RM). SARAH Rehabilitation Hospital Network, Brasilia, Brazil. Forty-five men aged 28.0 years with SCI between C6 and L2 causing complete motor impairment were enrolled in the study. Volunteers were tested, in a random order, in 1RM test or 4-12RM with 2-3 interval days. Multiple regression analysis was used to generate an equation for predicting 1RM. There were no significant differences between 1RM test and the current predictive equations. ICC values were significant and were classified as excellent for all current predictive equations. The predictive equation of Lombardi presented the best Bland-Altman results (0.5 kg and 12.8 kg for mean difference and interval range around the differences, respectively). The two created equation models for 1RM demonstrated the same and a high adjusted R 2 (0.971, P<0.01), but different SEE of measured 1RM (2.88 kg or 5.4% and 2.90 kg or 5.5%). All 1RM predictive equations are accurate to assess individuals with SCI at the bench press exercise. However, the predictive equation of Lombardi presented the best associated cross-validity results. A specific 1RM prediction equation was also elaborated for individuals with SCI. The created equation should be tested in order to verify whether it presents better accuracy than the current ones.

Inter-Investigator Reliability of Anthropometric Prediction of 1RM Bench Press in College Football Players

PubMed Central

SCHUMACHER, RICHARD M.; ARABAS, JANA L.; MAYHEW, JERRY L.; BRECHUE, WILLIAM F.

2016-01-01

The purpose of this study was to determine the effect of inter-investigator differences in anthropometric assessments on the prediction of one-repetition maximum (1RM) bench press in college football players. Division-II players (n = 34, age = 20.4 ± 1.2 y, 182.3 ± 6.6 cm, 99.1 ± 18.4 kg) were measured for selected anthropometric variables and 1RM bench press at the conclusion of a heavy resistance training program. Triceps, subscapular, and abdominal skinfolds were measured in triplicate by three investigators and used to estimate %fat. Arm circumference was measured around a flexed biceps muscle and was corrected for triceps skinfold to estimate muscle cross-sectional area (CSA). Chest circumference was measured at mid-expiration. Significant differences among the testers were evident in six of the nine anthropometric variables, with the least experienced tester being significantly different from the other testers on seven variables, although average differences among investigators ranged from 1–2% for circumferences to 4–9% for skinfolds. The two more experienced testers were significantly different on only one variable. Overall agreement among testers was high (ICC>0.895) for each variable, with low coefficients of variation (CV<10.7%). Predicted 1RMs for testers (126.9 ± 20.6, 123.4 ± 22.0, and 132.1 ± 28.4 kg, respectively) were not significantly different from actual 1RM (129.2 ± 20.6 kg). Individuals with varying levels of experience appear to have an acceptable level of ability to estimate 1RM bench press using a non-performance anthropometric equation. Minimal experience in anthropometry may not impede strength and conditioning specialists from accurately estimating 1RM bench press. PMID:27766130

Inter-Investigator Reliability of Anthropometric Prediction of 1RM Bench Press in College Football Players.

PubMed

Schumacher, Richard M; Arabas, Jana L; Mayhew, Jerry L; Brechue, William F

2016-01-01

The purpose of this study was to determine the effect of inter-investigator differences in anthropometric assessments on the prediction of one-repetition maximum (1RM) bench press in college football players. Division-II players (n = 34, age = 20.4 ± 1.2 y, 182.3 ± 6.6 cm, 99.1 ± 18.4 kg) were measured for selected anthropometric variables and 1RM bench press at the conclusion of a heavy resistance training program. Triceps, subscapular, and abdominal skinfolds were measured in triplicate by three investigators and used to estimate %fat. Arm circumference was measured around a flexed biceps muscle and was corrected for triceps skinfold to estimate muscle cross-sectional area (CSA). Chest circumference was measured at mid-expiration. Significant differences among the testers were evident in six of the nine anthropometric variables, with the least experienced tester being significantly different from the other testers on seven variables, although average differences among investigators ranged from 1-2% for circumferences to 4-9% for skinfolds. The two more experienced testers were significantly different on only one variable. Overall agreement among testers was high (ICC>0.895) for each variable, with low coefficients of variation (CV<10.7%). Predicted 1RMs for testers (126.9 ± 20.6, 123.4 ± 22.0, and 132.1 ± 28.4 kg, respectively) were not significantly different from actual 1RM (129.2 ± 20.6 kg). Individuals with varying levels of experience appear to have an acceptable level of ability to estimate 1RM bench press using a non-performance anthropometric equation. Minimal experience in anthropometry may not impede strength and conditioning specialists from accurately estimating 1RM bench press.

Muscle strength and regional lean body mass influence on mineral bone health in young male adults.

PubMed

Guimarães, Bianca Rosa; Pimenta, Luciana Duarte; Massini, Danilo Alexandre; Dos Santos, Daniel; Siqueira, Leandro Oliveira da Cruz; Simionato, Astor Reis; Dos Santos, Luiz Gustavo Almeida; Neiva, Cassiano Merussi; Pessôa Filho, Dalton Muller

2018-01-01

The relationship between muscle strength and bone mineral content (BMC) and bone mineral density (BMD) is supposed from the assumption of the mechanical stress influence on bone tissue metabolism. However, the direct relationship is not well established in younger men, since the enhancement of force able to produce effective changes in bone health, still needs to be further studied. This study aimed to analyze the influence of muscle strength on BMC and BMD in undergraduate students. Thirty six men (24.9 ± 8.6 y/o) were evaluated for regional and whole-body composition by dual energy X-ray absorptiometry (DXA). One repetition maximum tests (1RM) were assessed on flat bench-press (BP), lat-pull down (LPD), leg-curl (LC), knee extension (KE), and leg-press 45° (LP45) exercises. Linear regression modelled the relationships of BMD and BMC to the regional body composition and 1RM values. Measurements of dispersion and error (R2adj and standard error of estimate (SEE)) were tested, setting ρ at ≤0.05. The BMD mean value for whole-body was 1.12±0.09 g/cm2 and BMC attained 2477.9 ± 379.2 g. The regional lean mass (LM) in upper-limbs (UL) (= 6.80±1.21 kg) was related to BMC and BMD for UL (R2adj = 0.74, p<0.01, SEE = 31.0 g and R2adj = 0.63, SEE = 0.08 g/cm2), and LM in lower-limbs (LL) (= 19.13±2.50 kg) related to BMC and BMD for LL (R2adj = 0.68, p<0,01, SEE = 99.3 g and R2adj = 0.50, SEE = 0.20 g/cm2). The 1RM in BP was related to BMD (R2adj = 0.51, SEE = 0.09 g/cm2), which was the strongest relationship among values of 1RM for men; but, 1RM on LPD was related to BMC (R2adj = 0.47, p<0.01, SEE = 44.6 g), and LC was related to both BMC (R2adj = 0.36, p<0.01, SEE = 142.0 g) and BMD (R2adj = 0.29, p<0.01, SEE = 0.23 g/cm2). Hence, 1RM for multi-joint exercises is relevant to BMC and BMD in young men, strengthening the relationship between force and LM, and suggesting both to parametrizes bone mineral health.

Multi-modal exercise training and protein-pacing enhances physical performance adaptations independent of growth hormone and BDNF but may be dependent on IGF-1 in exercise-trained men.

PubMed

Ives, Stephen J; Norton, Chelsea; Miller, Vincent; Minicucci, Olivia; Robinson, Jake; O'Brien, Gabe; Escudero, Daniela; Paul, Maia; Sheridan, Caitlin; Curran, Kathryn; Rose, Kayla; Robinson, Nathaniel; He, Feng; Arciero, Paul J

2017-02-01

Protein-pacing (P; 5-6meals/day @ 2.0g/kgBW/day) and multi-mode exercise (RISE; resistance, interval, stretching, endurance) training (PRISE) improves muscular endurance, strength, power and arterial health in exercise-trained women. The current study extends these findings by examining PRISE on fitness, growth hormone (GH), insulin-like growth factor-1 (IGF-1), and brain-derived neurotrophic factor (BDNF) response, cardiometabolic health, and body composition in exercise-trained men. Twenty active males (>4daysexercise/week) completed either: PRISE (n=11) or RISE (5-6meals/day @ 1.0g/kgBW/day; n=9) for 12weeks. Muscular strength (1-repetition maximum bench and leg press, 1-RM BP, and 1-RM LP), endurance (sit-ups, SU; push-ups, PU), power (squat jump, SJ, and bench throw, BT), flexibility (sit-and-reach, SR), aerobic performance (5km cycling time-trial, TT), GH, IGF-1, BDNF, augmentation index, (AIx), and body composition, were assessed at weeks 0 (pre) and 13 (post). At baseline, no differences existed between groups except for GH (RISE, 230±13 vs. PRISE, 382±59pg/ml, p<0.05). The exercise intervention improved 1-RM, SJ, BT, PU, SU, SR, 5km-TT, GH, AIx, BP, and body composition in both groups (time, p<0.05). However, PRISE elicited greater improvements in 1-RM BP (21 vs. 10∆lbs), SJ (171 vs. 13∆W), 5km-TT (-37 vs. -11∆s), and sit-and-reach (5.3 vs. 1.2∆cm) over RISE alone (p<0.05) including increased IGF-1 (12%, p<0.05). Exercise-trained men consuming a P diet combined with multi-component exercise training (PRISE) enhance muscular power, strength, aerobic performance, and flexibility which are not likely related to GH or BDNF but possibly to IGF-1 response. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Isometric parameters in the monitoring of maximal strength, power, and hypertrophic resistance-training.

PubMed

Peltonen, Heikki; Walker, Simon; Lähitie, Anuliisa; Häkkinen, Keijo; Avela, Janne

2018-02-01

This study monitored strength-training adaptations via isometric parameters throughout 2 × 10 weeks of hypertrophic (HYP I-II) or 10 weeks maximum strength (MS) followed by 10 weeks power (P) training with untrained controls. Trainees performed bilateral isometric leg press tests analyzed for peak force (maximal voluntary contraction (MVC)) and rate of force development (RFD) every 3.5 weeks. These parameters were compared with dynamic performance, voluntary and electrically induced isometric contractions, muscle activity, and cross-sectional area (CSA) in the laboratory before and after 10 and 20 weeks. RFD increased similarly during the first 7 weeks (HYP I, 44% ± 53%; MS, 48% ± 55%, P < 0.05), but RFD continued to increase up to 65% ± 61% from baseline (P < 0.01) only during P. These increases were concomitant with enhanced dynamic performances of 1-repetition maximum (1RM) (HYP I, 8% ± 6%; MS, 11% ± 6%, P < 0.001), and explosive repetitions during P (11% ± 15%, P < 0.05). Time to reach peak RFD differed (P < 0.001) between HYP (mean 42 ± 20 ms) and MS-P (mean 31 ± 12 ms) groups because of training. The changes in MVC correlated with the changes in CSA during weeks 1-20 (HYP I-II, r = 0.664; MS-P, r = 0.595, P ≤ 0.05), as well as changes in 1RM (r = 0.724, P < 0.05) during weeks 11-20 (HYP II). Muscle activity increased during MS and P only. Both MVC and RFD improvements reflected combinations of central and peripheral adaptations. RFD parameters may be effective tools to evaluate adaptations, particularly during maximal strength/power training, while MVC cannot distinguish between strength or muscle mass changes. Monitoring RFD provided important information regarding plateaus in RFD improvement, which were observed in dynamic explosive performances after HYP II compared with P.

RPE vs. Percentage 1RM Loading in Periodized Programs Matched for Sets and Repetitions

PubMed Central

Helms, Eric R.; Byrnes, Ryan K.; Cooke, Daniel M.; Haischer, Michael H.; Carzoli, Joseph P.; Johnson, Trevor K.; Cross, Matthew R.; Cronin, John B.; Storey, Adam G.; Zourdos, Michael C.

2018-01-01

Purpose: To investigate differences between rating of perceived exertion (RPE) and percentage one-repetition maximum (1RM) load assignment in resistance-trained males (19–35 years) performing protocols with matched sets and repetitions differentiated by load-assignment. Methods: Participants performed squats then bench press 3x/weeks in a daily undulating format over 8-weeks. Participants were counterbalanced by pre-test 1RM then assigned to percentage 1RM (1RMG, n = 11); load-assignment via percentage 1RMs, or RPE groups (RPEG, n = 10); participant-selected loads to reach target RPE ranges. Ultrasonography determined pre and post-test pectoralis (PMT), and vastus lateralis muscle thickness at 50 (VLMT50) and 70% (VLMT70) femur-length. Results: Bench press (1RMG +9.64 ± 5.36; RPEG + 10.70 ± 3.30 kg), squat (1RMG + 13.91 ± 5.89; RPEG + 17.05 ± 5.44 kg) and their combined-total 1RMs (1RMG + 23.55 ± 10.38; RPEG + 27.75 ± 7.94 kg) increased (p < 0.05) in both groups as did PMT (1RMG + 1.59 ± 1.33; RPEG +1.90 ± 1.91 mm), VLMT50 (1RMG +2.13 ± 1.95; RPEG + 1.85 ± 1.97 mm) and VLMT70 (1RMG + 2.40 ± 2.22; RPEG + 2.31 ± 2.27 mm). Between-group differences were non-significant (p > 0.05). Magnitude-based inferences revealed 79, 57, and 72% chances of mean small effect size (ES) advantages for squat; ES 90% confidence limits (CL) = 0.50 ± 0.63, bench press; ES 90% CL = 0.28 ± 0.73, and combined-total; ES 90% CL = 0.48 ± 0.68 respectively, in RPEG. There were 4, 14, and 6% chances 1RMG had a strength advantage of the same magnitude, and 18, 29, and 22% chances, respectively of trivial differences between groups. Conclusions: Both loading-types are effective. However, RPE-based loading may provide a small 1RM strength advantage in a majority of individuals. PMID:29628895

The effects of varying resistance-training loads on intermediate- and high-velocity-specific adaptations.

PubMed

Jones, K; Bishop, P; Hunter, G; Fleisig, G

2001-08-01

The purpose of this study was to compare changes in velocity-specific adaptations in moderately resistance-trained athletes who trained with either low or high resistances. The study used tests of sport-specific skills across an intermediate- to high-velocity spectrum. Thirty NCAA Division I baseball players were randomly assigned to either a low-resistance (40-60% 1 repetition maximum [1RM]) training group or a high-resistance (70-90% 1RM) training group. Both of the training groups intended to maximallv accelerate each repetition during the concentric phase (IMCA). The 10 weeks of training consisted of 4 training sessions a week using basic core exercises. Peak force, velocity, and power were evaluated during set angle and depth jumps as well as weighted jumps using 30 and 50% 1RM. Squat 1RMs were also tested. Although no interactions for any of the jump tests were found, trends supported the hypothesis of velocity-specific training. Percentage gains suggest that the combined use of heavier training loads (70-90% 1RM) and IMCA tend to increase peak force in the lower-body leg and hip extensors. Trends also show that the combined use of lighter training loads (40-60% 1RM) and IMCA tend to increase peak power and peak velocity in the lower-body leg and hip extensors. The high-resistance group improved squats more than the low-resistance group (p < 0.05; +22.7 vs. + 16.1 kg). The results of this study support the use of a combination of heavier training loads and IMCA to increase 1RM strength in the lower bodies of resistance-trained athletes.

Whistler turbulence heating of electrons and ions: Three-dimensional particle-in-cell simuations

DOE PAGES

Gary, S. Peter; Hughes, R. Scott; Wang, Joseph

2016-01-14

In this study, the decay of whistler turbulence in a collisionless, homogeneous, magnetized plasma is studied using three-dimensional particle-in-cell simulations. The simulations are initialized with a narrowband, relatively isotropic distribution of long wavelength whistler modes. A first ensemble of simulations at electron betamore » $${\\beta }_{{\\rm{e}}}$$ = 0.25 and ion-to-electron mass ratio $${m}_{{\\rm{i}}}$$/$${m}_{{\\rm{e}}}$$ = 400 is carried out on a domain cube of dimension $$L{\\omega }_{\\mathrm{pi}}$$/c = 5.12 where $${\\omega }_{\\mathrm{pi}}$$ is the ion plasma frequency. The simulations begin with a range of dimensionless fluctuating field energy densities, $${\\epsilon }_{{\\rm{o}}}$$, and follow the fluctuations as they cascade to broadband, anisotropic turbulence which dissipates at shorter wavelengths, heating both electrons and ions. The electron heating is stronger and preferentially parallel/antiparallel to the background magnetic field $${{\\boldsymbol{B}}}_{{\\rm{o}}};$$ the ion energy gain is weaker and is preferentially in directions perpendicular to $${{\\boldsymbol{B}}}_{{\\rm{o}}}$$. The important new results here are that, over 0.01 < $${\\epsilon }_{{\\rm{o}}}$$ < 0.25, the maximum rate of electron heating scales approximately as $${\\epsilon }_{{\\rm{o}}}$$, and the maximum rate of ion heating scales approximately as $${\\epsilon }_{{\\rm{o}}}^{1.5}$$. A second ensemble of simulations at $${\\epsilon }_{{\\rm{o}}}$$ = 0.10 and $${\\beta }_{{\\rm{e}}}$$ = 0.25 shows that, over 25 < $${m}_{{\\rm{i}}}$$/$${m}_{{\\rm{e}}}\\;$$< 1836, the ratio of the maximum ion heating rate to the maximum electron heating rate scales approximately as $${m}_{{\\rm{e}}}$$/$${m}_{{\\rm{i}}}$$.« less

Effects of strength training on muscle strength characteristics, functional capabilities, and balance in middle-aged and older women.

PubMed

Holviala, Jarkko H S; Sallinen, Janne M; Kraemer, William J; Alen, Markku J; Häkkinen, Keijo K T

2006-05-01

Progressive strength training can lead to substantial increases in maximal strength and mass of trained muscles, even in older women and men, but little information is available about the effects of strength training on functional capabilities and balance. Thus, the effects of 21 weeks of heavy resistance training--including lower loads performed with high movement velocities--twice a week on isometric maximal force (ISOmax) and force-time curve (force produced in 500 milliseconds, F0-500) and dynamic 1 repetition maximum (1RM) strength of the leg extensors, 10-m walking time (10WALK) and dynamic balance test (DYN.D) were investigated in 26 middle-aged (MI; 52.8 +/- 2.4 years) and 22 older women (O; 63.8 +/- 3.8 years). 1RM, ISOmax, and F0-500 increased significantly in MI by 28 +/- 10%, 20 +/- 19%, 31 +/- 34%, and in O by 27 +/- 8%, 20 +/- 16%, 18 +/- 45%, respectively. 10WALK (MI and O, p < 0.001) shortened and DYN.D improved (MI and O, p < 0.001). The present strength-training protocol led to large increases in maximal and explosive strength characteristics of leg extensors and in walking speed, as well to an improvement in the present dynamic balance test performance in both age groups. Although training-induced increase in explosive strength is an important factor for aging women, there are other factors that contribute to improvements in dynamic balance capacity. This study indicates that total body heavy resistance training, including explosive dynamic training, may be applied in rehabilitation or preventive exercise protocols in aging women to improve dynamic balance capabilities.

Effects of Partner's Improvisational Resistance Training on dancers' muscular strength.

PubMed

Vetter, Rheba E; Dorgo, Sandor

2009-05-01

The purpose of this study was to observe the effects of Partner's Improvisational Resistance Training (PIRT) on muscular strength, body circumference, and body fat percentage in 10 female college-age dancers in comparison with 8 female dancers in a control group. The PIRT program, based on the concepts of manual resistance training, is the application of contact improvisation in a systematic strength development program, which proposes a way of contextualizing muscular strength development within the dance class. The program lasted 8 weeks, meeting 3 times weekly for 60-minute sessions. The muscular strength pre- and posttests included 1-repetition maximum (1RM) for leg extension, leg flexion, leg press, bench press, lat pulldown, back extension, and modified sit-up. Hydrostatic weighing for body composition and circumference measures on the waist, hip, shoulder, upper arm, and thigh were made pre- and posttest analyses. There were no significant pretest differences between the groups for age, height, body weight, body fat percentage, any of the circumference measures, or 5 of the 7 muscular strength measures. At posttest, neither group showed significant changes in total body weight, body fat percentage, or lean body weight. The experimental group showed significant decrements in the waist and hip circumference measures, and all other body circumference changes were nonsignificant. The experimental group showed significant changes from pretest to posttest for all seven 1RM strength measures and greater absolute and relative strength improvements in 5 measures compared with the control group. Thus, the 8-week PIRT program for female dancers was found effective in improving overall muscular strength and decreasing circumference in the waist-hip region, but it did not elicit significant changes in body composition.

Effects of High-Speed Power Training on Muscle Performance and Braking Speed in Older Adults

PubMed Central

Sayers, Stephen P.; Gibson, Kyle

2012-01-01

We examined whether high-speed power training (HSPT) improved muscle performance and braking speed using a driving simulator. 72 older adults (22 m, 50 f; age = 70.6 ± 7.3 yrs) were randomized to HSPT at 40% one-repetition maximum (1RM) (HSPT: n = 25; 3 sets of 12–14 repetitions), slow-speed strength training at 80%1RM (SSST: n = 25; 3 sets of 8–10 repetitions), or control (CON: n = 22; stretching) 3 times/week for 12 weeks. Leg press and knee extension peak power, peak power velocity, peak power force/torque, and braking speed were obtained at baseline and 12 weeks. HSPT increased peak power and peak power velocity across a range of external resistances (40–90% 1RM; P < 0.05) and improved braking speed (P < 0.05). Work was similar between groups, but perceived exertion was lower in HSPT (P < 0.05). Thus, the less strenuous HSPT exerted a broader training effect and improved braking speed compared to SSST. PMID:22500229

Effects of Training Attendance on Muscle Strength of Young Men after 11 Weeks of Resistance Training

PubMed Central

Gentil, Paulo; Bottaro, Martim

2013-01-01

Purpose Training attendance is an important variable for attaining optimal results after a resistance training (RT) program, however, the association of attendance with the gains of muscle strength is not well defined. Therefore, the purpose of the present study is to verify if attendance would affect muscle strength gains in healthy young males. Methods Ninety two young males with no previous RT experience volunteered to participate in the study. RT was performed 2 days a week for 11 weeks. One repetition maximum (1RM) in the bench press and knee extensors peak torque (PT) were measured before and after the training period. After the training period, a two step cluster analysis was used to classify the participants in accordance to training attendance, resulting in three groups, defined as high (92 to 100%), intermediate (80 to 91%) and low (60 to 79%) training attendance. Results According to the results, there were no significant correlations between strength gains and training attendance, however, when attendance groups were compared, the low training attendance group showed lower increases in 1RM bench press (8.8%) than the other two groups (17.6% and 18.0% for high and intermediate attendance, respectively). Conclusions Although there is not a direct correlation between training attendance and muscle strength gains, it is suggested that a minimum attendance of 80% is necessary to ensure optimal gains in upper body strength. PMID:23802051

Muscle Power Is an Independent Determinant of Pain and Quality of Life in Knee Osteoarthritis.

PubMed

Reid, Kieran F; Price, Lori Lyn; Harvey, William F; Driban, Jeffrey B; Hau, Cynthia; Fielding, Roger A; Wang, Chenchen

2015-12-01

This study examined the relationships between leg muscle strength, power, and perceived disease severity in subjects with knee osteoarthritis (OA) in order to determine whether dynamic leg extensor muscle power would be associated with pain and quality of life in knee OA. Baseline data on 190 subjects with knee OA (mean ± SD age 60.2 ± 10.4 years, body mass index 32.7 ± 7.2 kg/m(2) ) were obtained from a randomized controlled trial. Knee pain was measured using the Western Ontario and McMaster Universities Osteoarthritis Index, and health-related quality of life was assessed using the Short Form 36 (SF-36). One-repetition maximum (1RM) strength was assessed using the bilateral leg press, and peak muscle power was measured during 5 maximum voluntary velocity repetitions at 40% and 70% of 1RM. In univariate analysis, greater muscle power was significantly associated with pain (r = -0.17, P < 0.02) and also significantly and positively associated with SF-36 physical component summary (PCS) scores (r = 0.16, P < 0.05). After adjustment for multiple covariates, muscle power was a significant independent predictor of pain (P ≤ 0.05) and PCS scores (P ≤ 0.04). However, muscle strength was not an independent determinant of pain or quality of life (P ≥ 0.06). Muscle power is an independent determinant of pain and quality of life in knee OA. Compared to strength, muscle power may be a more clinically important measure of muscle function within this population. New trials to systematically examine the impact of muscle power training interventions on disease severity in knee OA are particularly warranted. © 2015, American College of Rheumatology.

Potentiation Effects of Half-Squats Performed in a Ballistic or Nonballistic Manner.

PubMed

Suchomel, Timothy J; Sato, Kimitake; DeWeese, Brad H; Ebben, William P; Stone, Michael H

2016-06-01

This study examined and compared the acute effects of ballistic and nonballistic concentric-only half-squats (COHSs) on squat jump performance. Fifteen resistance-trained men performed a squat jump 2 minutes after a control protocol or 2 COHSs at 90% of their 1 repetition maximum (1RM) COHS performed in a ballistic or nonballistic manner. Jump height (JH), peak power (PP), and allometrically scaled peak power (PPa) were compared using three 3 × 2 repeated-measures analyses of variance. Statistically significant condition × time interaction effects existed for JH (p = 0.037), PP (p = 0.041), and PPa (p = 0.031). Post hoc analysis revealed that the ballistic condition produced statistically greater JH (p = 0.017 and p = 0.036), PP (p = 0.031 and p = 0.026), and PPa (p = 0.024 and p = 0.023) than the control and nonballistic conditions, respectively. Small effect sizes for JH, PP, and PPa existed during the ballistic condition (d = 0.28-0.44), whereas trivial effect sizes existed during the control (d = 0.0-0.18) and nonballistic (d = 0.0-0.17) conditions. Large statistically significant relationships existed between the JH potentiation response and the subject's relative back squat 1RM (r = 0.520; p = 0.047) and relative COHS 1RM (r = 0.569; p = 0.027) during the ballistic condition. In addition, large statistically significant relationship existed between JH potentiation response and the subject's relative back squat strength (r = 0.633; p = 0.011), whereas the moderate relationship with the subject's relative COHS strength trended toward significance (r = 0.483; p = 0.068). Ballistic COHS produced superior potentiation effects compared with COHS performed in a nonballistic manner. Relative strength may contribute to the elicited potentiation response after ballistic and nonballistic COHS.

Training Strategies to Improve Muscle Power: Is Olympic-style Weightlifting Relevant?

PubMed

Helland, Christian; Hole, Eirik; Iversen, Erik; Olsson, Monica Charlotte; Seynnes, Olivier; Solberg, Paul Andre; Paulsen, Gøran

2017-04-01

This efficacy study investigated the effects of 1) Olympic-style weightlifting (OWL), 2) motorized strength and power training (MSPT), and 3) free weight strength and power training (FSPT) on muscle power. Thirty-nine young athletes (20 ± 3 yr; ice hockey, volleyball, and badminton) were randomized into the three training groups. All groups participated in two to three sessions per week for 8 wk. The MSPT and FSPT groups trained using squats (two legs and single leg) with high force and high power, whereas the OWL group trained using clean and snatch exercises. MSPT was conducted as slow-speed isokinetic strength training and isotonic power training with augmented eccentric load, controlled by a computerized robotic engine system. FSPT used free weights. The training volume (sum of repetitions × kg) was similar between all three groups. Vertical jumping capabilities were assessed by countermovement jump (CMJ), squat jump (SJ), drop jump (DJ), and loaded CMJ (10-80 kg). Sprinting capacity was assessed in a 30-m sprint. Secondary variables were squat one-repetition maximum (1RM), body composition, quadriceps thickness, and architecture. OWL resulted in trivial improvements and inferior gains compared with FSPT and MSPT for CMJ, SJ, DJ, and 1RM. MSPT demonstrated small but robust effects on SJ, DJ, loaded CMJ, and 1RM (3%-13%). MSPT was superior to FSPT in improving 30-m sprint performance. FSPT and MSPT, but not OWL, demonstrated increased thickness in the vastus lateralis and rectus femoris (4%-7%). MSPT was time-efficient and equally or more effective than FSPT training in improving vertical jumping and sprinting performance. OWL was generally ineffective and inferior to the two other interventions.

Comparison of physical performance among Brazilian elite soccer players of different age-categories.

PubMed

Kobal, Ronaldo; Loturco, Irineu; Gil, Saulo; Cal Abad, Cesar C; Cuniyochi, Rogério; Barroso, Renato; Tricoli, Valmor

2016-04-01

The purpose of this study was to compare the physical performance (i.e., strength, power, speed and endurance) between Brazilian elite soccer players from different categories of the same club: professionals (PRO), under-20 (U-20), and under-17 (U-17). Seventy-one soccer players from three categories (PRO=24; U-20=21 and U-17=26) were assessed at the beginning of pre-season. Before the tests, they were familiarized with all experimental procedures. Squat jump (SJ), countermovement jump (CMJ), sprint (10 m/20 m), maximum dynamic strength (1RM), and Yo-Yo intermittent recovery tests level 1 were performed in three non-consecutive sessions. No significant differences were found between the categories for sprint times. The PRO players presented higher outcomes in the 1RM, SJ, CMJ, and Yo-Yo tests than the U-20 and U-17 players (P≤0.05). No significant differences were found between the U-20 and U-17 players in 1RM, and SJ/CMJ heights. The U-20 presented superior performance than the U-17 in the Yo-Yo test (P≤0.05). The findings indicated that PRO performed better than younger players in all assessments, except for the sprint tests. This may have been possible due to the differences in training experience, technical expertise and individual levels of strength/power. However, the absence of differences between the U-20 and U-17 groups highlighted the necessity of developing specific training strategies in order to improve the physical capacities of younger players, throughout the maturation process. Moreover, due to the importance of sprinting in soccer, it is strongly recommended that fitness coaches develop more effective strategies to improve speed ability in professional players.

Effects of Different Combinations of Strength, Power, and Plyometric Training on the Physical Performance of Elite Young Soccer Players.

PubMed

Kobal, Ronaldo; Loturco, Irineu; Barroso, Renato; Gil, Saulo; Cuniyochi, Rogério; Ugrinowitsch, Carlos; Roschel, Hamilton; Tricoli, Valmor

2017-06-01

The combination of strength (ST) and plyometric training (PT) has been shown to be effective for improving sport-specific performance. However, there is no consensus about the most effective way to combine these methods in the same training session to produce greater improvements in neuromuscular performance of soccer players. Thus, the purpose of this study was to compare the effects of different combinations of ST and PT sequences on strength, jump, speed, and agility capacities of elite young soccer players. Twenty-seven soccer players (age: 18.9 ± 0.6 years) participated in an 8-week resistance training program and were divided into 3 groups: complex training (CP) (ST before PT), traditional training (TD) (PT before ST), and contrast training (CT) (ST and PT performed alternately, set by set). The experimental design took place during the competitive period of the season. The ST composed of half-squat exercises performed at 60-80% of 1 repetition maximum (1RM); the PT composed of drop jump exercises executed in a range from 30 to 45 cm. After the experimental period, the maximum dynamic strength (half-squat 1RM) and vertical jump ability (countermovement jump height) increased similarly and significantly in the CP, TD, and CT (48.6, 46.3, and 53% and 13, 14.2, and 14.7%, respectively). Importantly, whereas the TD group presented a significant decrease in sprinting speed in 10 (7%) and 20 m (6%), the other groups did not show this response. Furthermore, no significant alterations were observed in agility performance in any experimental group. In conclusion, in young soccer players, different combinations and sequences of ST and PT sets result in similar performance improvements in muscle strength and jump ability. However, it is suggested that the use of the CP and CT methods is more indicated to maintain/maximize the sprint performance of these athletes.

Effects of light-load maximal lifting velocity weight training vs. combined weight training and plyometrics on sprint, vertical jump and strength performance in adult soccer players.

PubMed

Rodríguez-Rosell, David; Torres-Torrelo, Julio; Franco-Márquez, Felipe; González-Suárez, José Manuel; González-Badillo, Juan José

2017-07-01

The purpose of this study was to compare the effects of combined light-load maximal lifting velocity weight training (WT) and plyometric training (PT) with WT alone on strength, jump and sprint performance in semiprofessional soccer players. Experimental, pre-post tests measures. Thirty adult soccer players were randomly assigned into three groups: WT alone (FSG, n=10), WT combined to jump and sprint exercises (COM, n=10) and control group (CG, n=10). WT consisted of full squat with low load (∼45-60% 1RM) and low volume (4-6 repetitions). Training program was performed twice a week for 6 weeks of competitive season in addition to 4 soccer sessions a week. Sprint time in 10 and 20m, jump height (CMJ), estimated one-repetition maximum (1RM est ) and velocity developed against different absolute loads in full squat were measured before and after training period. Both experimental groups showed significant improvements in 1RM est (17.4-13.4%; p<0.001), CMJ (7.1-5.2%; p<0.001), sprint time (3.6-0.7%; p<0.05-0.001) and force-velocity relationships (16.9-6.1%; p<0.05-0.001), whereas no significant gains were found in CG. No significant differences were found between FSG and COM. Despite FSG resulted of greater increases in strength variables than COM, this may not translate into superior improvements in the sport-related performance. In fact, COM showed higher efficacy of transfer of strength gains to sprint ability. Therefore, these findings suggest that a combined WT and PT program could represent a more efficient method for improving activities which involve acceleration, deceleration and jumps compared to WT alone. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Effects of Two Different Training Periodization Models on Physical and Physiological Aspects of Elite Female Team Handball Players.

PubMed

Manchado, Carmen; Cortell-Tormo, Juan M; Tortosa-Martínez, Juan

2018-01-01

Manchado, C, Cortell-Tormo, JM, and Tortosa-Martínez, J. Effects of two different training periodization models on physical and physiological aspects of elite female team handball players. J Strength Cond Res 32(1): 280-287, 2018-The aim of this study was to compare training-induced changes in selected physiological and physical team handball performance factors after 2 training periodization models: traditional periodization (TP) vs. block periodization (BP). Eleven female team handball players who played over 2 consecutive seasons for a Spanish first league team were assessed twice per season during a training cycle. On each occasion, participants completed anthropometric, maximal strength, and lower-body power assessments. In addition, incremental tests to determine maximum oxygen uptake (V[Combining Dot Above]O2max), sprint- and sport-specific throwing velocity tests were performed. Block periodization group experienced significantly greater improvements than TP on squat jump (5.97%; p < 0.001), countermovement jump (8.76%; p = 0.011), hand-grip strength (8.22%; p = 0.029), bench press 1 repetition maximum (1RM) (5.14%; p = 0.049), 10-m sprint (-6.19%; p < 0.001), and 20-m sprint (2.95%; p = 0.008). Greater changes in BP group (p ≤ 0.05) were also found for the throwing velocities in sport-specific tests compared with the TP group. No significant difference between the groups were detected for the half-squat 1RM (p = 0.15) and the V[Combining Dot Above]O2max (p = 0.44). These findings suggest that BP may be more effective than TP for improving important physiological and physical team handball performance factors in high level female handball players.

FARADAY ROTATION STRUCTURE ON KILOPARSEC SCALES IN THE RADIO LOBES OF CENTAURUS A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feain, I. J.; Ekers, R. D.; Norris, R. P.

2009-12-10

We present the results of an Australia Telescope Compact Array 1.4 GHz spectropolarimetric aperture synthesis survey of 34 deg{sup 2} centered on Centaurus A-NGC 5128. A catalog of 1005 extragalactic compact radio sources in the field to a continuum flux density of 3 mJy beam{sup -1} is provided along with a table of Faraday rotation measures (RMs) and linear polarized intensities for the 28% of sources with high signal to noise in linear polarization. We use the ensemble of 281 background polarized sources as line-of-sight probes of the structure of the giant radio lobes of Centaurus A. This is themore » first time such a method has been applied to radio galaxy lobes and we explain how it differs from the conventional methods that are often complicated by depth and beam depolarization effects. Assuming a magnetic field strength in the lobes of 1.3 B {sub 1} muG, where B {sub 1} = 1 is implied by equipartition between magnetic fields and relativistic particles, the upper limit we derive on the maximum possible difference between the average RM of 121 sources behind Centaurus A and the average RM of the 160 sources along sightlines outside Centaurus A implies an upper limit on the volume-averaged thermal plasma density in the giant radio lobes of (n{sub e} ) < 5 x 10{sup -5} B {sup -1} {sub 1} cm{sup -3}. We use an RM structure function analysis and report the detection of a turbulent RM signal, with rms sigma{sub RM} = 17 rad m{sup -2} and scale size 0.{sup 0}3, associated with the southern giant lobe. We cannot verify whether this signal arises from turbulent structure throughout the lobe or only in a thin skin (or sheath) around the edge, although we favor the latter. The RM signal is modeled as possibly arising from a thin skin with a thermal plasma density equivalent to the Centaurus intragroup medium density and a coherent magnetic field that reverses its sign on a spatial scale of 20 kpc. For a thermal density of n {sub 1} 10{sup -3} cm{sup -3}, the skin magnetic field strength is 0.8 n {sup -1} {sub 1} muG.« less

Bench press training program with attached chains for female volleyball and basketball athletes.

PubMed

Burnham, Timothy R; Ruud, Jason D; McGowan, Robert

2010-02-01

Attaching chains to barbells to increase strength and power has become popular for athletes; however, little scientific evidence supports this practice. The present purpose was to compare chain training to traditional training for the bench press. Women collegiate athletes in volleyball and basketball (N = 19) participated in a 16-session bench press program. They were matched into either a Traditional or a Chain training group by 1-repetition maximum (1RM). The Traditional group performed the bench press with conventional equipment, while the Chain group trained with attached chains (5% of weight). Analysis showed a significant increase in 1RM for both groups over 16 sessions, Traditional +11.8% and Chain +17.4%. The difference between the groups was not statistically significant, but suggests the women who trained with attached chains improved their bench press more than the Traditional group.

Comparison of the effect of different surface treatments on the bond strength of different cements with nickel chromium metal alloy: An in vitro study

PubMed Central

Kapoor, Saumya; Balakrishnan, Dhanasekar

2017-01-01

Background For success of any indirect metal restoration, a strong bond between cement and the intaglio surface of metal is imperative. The aim of this study is to evaluate and compare the effect of different surface treatment on the tensile and shear bond strength of different cements with nickel–chromium alloy. Material and Methods 120 premolars were sectioned horizontally parallel to the occlusal surface to expose the dentin. Wax patterns were fabricated for individual tooth followed by casting them in nickel chromium alloy. 60 samples were tested for tensile bond strength, and the remaining 60 for shear bond strength. The samples were divided into three groups (of 20 samples each) as per the following surface treatment: oxidation only, oxidation and sandblasting, or oxidation, sandblasting followed by application of alloy primer. Each group was subdivided into 2 subgroups of 10 samples each, according to the bonding cement i.e RM-GIC and resin cement. Samples were subjected to thermocycling procedure followed by evaluation of bond strength. Results Two-way analyses of variance (ANOVA) was performed to compare the means of tensile and shear bond strength across type of surface treatment and cement, followed by post hoc parametric analysis. For all tests ‘p’ value of less than 0.05 was considered statistically significant. Conclusions The surface treatment of oxidation and sandblasting followed by application of alloy primer offered the maximum tensile and shear bond strength for both RM GIC and resin cement. Resin cement exhibited greater tensile and shear bond strength than RM-GIC for all the three surface treatment methods. Key words:Resin cement, resin modified glass ionomer cement, oxidation, sandblasting, alloy primer, tensile bond strength, shear bond strength, universal testing machine. PMID:28828160

Therapeutic effects of maximal strength training on walking efficiency in patients with schizophrenia - a pilot study.

PubMed

Heggelund, Jørn; Morken, Gunnar; Helgerud, Jan; Nilsberg, Geir E; Hoff, Jan

2012-07-03

Patients with schizophrenia frequently have disabling gait deficits. The net mechanical efficiency of walking (ϵnet) is an accurate measure often used to evaluate walking performance. Patients with gait deficits have a reduced ϵnet with excessive energy expenditure during sub-maximal walking. Maximal strength training (MST) improves ϵnet in healthy individuals and is associated with reduced risk of mortality. The aim of this study was to investigate whether MST improves ϵnet in patients with schizophrenia. Patients (ICD-10 schizophrenia, schizotypal or delusional disorders (F20-F29)) were included in a non-randomized trial. Patients were assigned to one of two groups: 1) MST consisting of 4x4 repetitions at 85-90% one repetition maximum (1RM) performed in a leg press apparatus or 2) playing computer games (CG). Both groups carried out their activity three days per week for eight weeks. 1RM, ϵnet at 60 watt walking, peak oxygen uptake (VO2peak), the Positive and Negative Syndrome Scale (PANSS) and the 36-items short form (SF-36) were measured pre and post intervention. The baseline ϵnet was 17.3 ± 1.2% and 19.4 ± 3.0% in the MST (n = 6) and CG groups (n = 7), respectively, which is categorized as mechanical inefficiency. The MST group improved 1RM by 79 kg (p = 0.006) and ϵnet by 3.4% (p = 0.046) more than the CG group. The MST group improved 1RM and ϵnet, by a mean of 83 kg (p = 0.028) and 3.4% (p = 0.028), respectively. VO2peak at baseline was 34.2 ± 10.2 and 38.3 ± 9.8 ml·kg-1·min-1 in the MST and CG groups, respectively, and did not change (p > 0.05). No change was observed in PANSS or SF-36 (p > 0.05). MST improves 1RM and ϵnet in patients with schizophrenia. MST could be used as a therapeutic intervention for patients with schizophrenia to normalize their reduced ϵnet.

Relationship between strength, power, speed, and change of direction performance of female softball players.

PubMed

Nimphius, Sophia; McGuigan, Michael R; Newton, Robert U

2010-04-01

The purpose of this study was to investigate (a) the cross-sectional relationship of strength, power, and performance variables in trained female athletes and (b) determine if the relationship between these variables changes over the course of a season. Ten female softball players (age = 18.1 +/- 1.6 years, height = 166.5 +/- 8.9 cm, and weight = 72.4 +/- 10.8 kg) from a state Australian Institute of Sport softball team were tested for maximal lower body strength (one repetition maximum [1RM]), peak force (PF), peak velocity (PV), and peak power (PP) during jump squats unloaded and loaded, unloaded countermovement vertical jump height (VJH) 1 base and 2 base sprint performance and change of direction performance on dominant and nondominant sides. The testing sessions occurred pre, mid, and post a 20-week training period. Relationship between body weight (BW), relative strength (1RM/BW), VJH, relative PP, relative PF, PV, speed, and change of direction variables were assessed by Pearson product-moment correlation coefficient at each testing session. Significant relationships were found across all time points with BW, speed, and change of direction measures (r = 0.70-0.93) and relative strength and measures of speed and change of direction ability (r = -0.73-0.85). There were no significant relationships between VJH and any measure of performance at any time point. In conclusion, BW and relative strength have strong to very strong correlations with speed and change of direction ability, and these correlations remain consistent over the course of the season. However, it seems as if many relationships vary with time, and their relationships should therefore be investigated longitudinally to better determine if these cross-sectional relationships truly reflect a deterministic relationship.

Measures of health, fitness, and functional movement among firefighter recruits.

PubMed

Cornell, David J; Gnacinski, Stacy L; Zamzow, Aaron; Mims, Jason; Ebersole, Kyle T

2017-06-01

The purpose of this study was to examine the associations between various health and fitness measures and Functional Movement Screen™ (FMS™) scores among 78 firefighter recruits. Relationships between FMS™ scores and age, body mass index (BMI), sit and reach (S&R) distance, estimated maximal aerobic capacity (V˙ O2max ), estimated one-repetition maximum squat (1RM-Squat max ), and plank endurance (%Plank max ) were examined. Total FMS™ scores were significantly correlated with BMI (r = -0.231, p = 0.042), estimated 1RM-Squat max (r = 0.302, p = 0.007), and %Plank max (r = 0.320, p = 0.004). Multiple regression analyses indicated that this combination of predictors significantly predicted (F(3, 74) = 5.043, p = 0.003) Total FMS™ score outcomes and accounted for 17% of the total variance (R 2  = 0.170). In addition, logistic regression analyses indicated that estimated 1RM-Squat max also significantly predicted (χ 2  = 6.662, df = 1, p = 0.010) FMS™ group membership (≤14 or ≥15). These results suggest that the health and fitness measures of obesity (BMI), bilateral lower extremity strength (estimated 1RM-Squat max ), and core muscular endurance (%Plank max ) are significantly associated with functional movement patterns among firefighter recruits. Consequently, injury prevention programs implemented among firefighter recruits should target these aspects of health and fitness.

One repetition maximum bench press performance: a new approach for its evaluation in inexperienced males and females: a pilot study.

PubMed

Bianco, Antonino; Filingeri, Davide; Paoli, Antonio; Palma, Antonio

2015-04-01

The aim of this study was to evaluate a new method to perform the one repetition maximum (1RM) bench press test, by combining previously validated predictive and practical procedures. Eight young male and 7 females participants, with no previous experience of resistance training, performed a first set of repetitions to fatigue (RTF) with a workload corresponding to ⅓ of their body mass (BM) for a maximum of 25 repetitions. Following a 5-min recovery period, a second set of RTF was performed with a workload corresponding to ½ of participants' BM. The number of repetitions performed in this set was then used to predict the workload to be used for the 1RM bench press test using Mayhew's equation. Oxygen consumption, heart rate and blood lactate were monitored before, during and after each 1RM attempt. A significant effect of gender was found on the maximum number of repetitions achieved during the RTF set performed with ½ of participants' BM (males: 25.0 ± 6.3; females: 11.0x± 10.6; t = 6.2; p < 0.001). The 1RM attempt performed with the workload predicted by Mayhew's equation resulted in females performing 1.2 ± 0.7 repetitions, while males performed 4.8 ± 1.9 repetitions. All participants reached their 1RM performance within 3 attempts, thus resulting in a maximum of 5 sets required to successfully perform the 1RM bench press test. We conclude that, by combining previously validated predictive equations with practical procedures (i.e. using a fraction of participants' BM to determine the workload for an RTF set), the new method we tested appeared safe, accurate (particularly in females) and time-effective in the practical evaluation of 1RM performance in inexperienced individuals. Copyright © 2014 Elsevier Ltd. All rights reserved.

A Repeated Power Training Enhances Fatigue Resistance While Reducing Intraset Fluctuations.

PubMed

Gonzalo-Skok, Oliver; Tous-Fajardo, Julio; Moras, Gerard; Arjol-Serrano, José Luis; Mendez-Villanueva, Alberto

2018-04-04

Oliver, GS, Julio, TF, Moras, G, José Luis, AS, and Alberto, MV. A repeated power training enhances fatigue resistance while reducing intraset fluctuations. J Strength Cond Res XX(X): 000-000, 2018-The present study analyzed the effects of adding an upper-body repeated power ability (RPA) training to habitual strength training sessions. Twenty young elite male basketball players were randomly allocated into a control group (CON, n = 10) or repeated power group (RPG, n = 10) and evaluated by 1 repetition maximum (1RM), incremental load, and RPA tests in the bench press exercise before and after a 7-week period and a 4-week cessation period. Repeated power group performed 1-3 blocks of 5 sets of 5 repetitions using the load that maximized power output with 30 seconds and 3 minute of passive recovery between sets and blocks, respectively. Between-group analysis showed substantial greater improvements in RPG compared with CON in: best set (APB), last set (APL), mean power over 5 sets (APM), percentage of decrement, fluctuation decrease during APL and RPA index (APLpost/APBpre) during the RPA test (effect size [ES] = 0.64-1.86), and 1RM (ES = 0.48) and average power at 80% of 1RM (ES = 1.11) in the incremental load test. The improvements of APB and APM were almost perfectly correlated. In conclusion, RPA training represents an effective method to mainly improve fatigue resistance together with the novel finding of a better consistency in performance (measured as reduced intraset power fluctuations) at the end of a dynamic repeated effort.

The Effects of Creatine Supplementation on Explosive Performance and Optimal Individual Postactivation Potentiation Time.

PubMed

Wang, Chia-Chi; Yang, Ming-Ta; Lu, Kang-Hao; Chan, Kuei-Hui

2016-03-04

Creatine plays an important role in muscle energy metabolism. Postactivation potentiation (PAP) is a phenomenon that can acutely increase muscle power, but it is an individualized process that is influenced by muscle fatigue. This study examined the effects of creatine supplementation on explosive performance and the optimal individual PAP time during a set of complex training bouts. Thirty explosive athletes performed tests of back squat for one repetition maximum (1RM) strength and complex training bouts for determining the individual optimal timing of PAP, height and peak power of a counter movement jump before and after the supplementation. Subjects were assigned to a creatine or placebo group and then consumed 20 g of creatine or carboxymethyl cellulose per day for six days. After the supplementation, the 1RM strength in the creatine group significantly increased (p < 0.05). The optimal individual PAP time in the creatine group was also significant earlier than the pre-supplementation and post-supplementation of the placebo group (p < 0.05). There was no significant difference in jump performance between the groups. This study demonstrates that creatine supplementation improves maximal muscle strength and the optimal individual PAP time of complex training but has no effect on explosive performance.

The Effects of Creatine Supplementation on Explosive Performance and Optimal Individual Postactivation Potentiation Time

PubMed Central

Wang, Chia-Chi; Yang, Ming-Ta; Lu, Kang-Hao; Chan, Kuei-Hui

2016-01-01

Creatine plays an important role in muscle energy metabolism. Postactivation potentiation (PAP) is a phenomenon that can acutely increase muscle power, but it is an individualized process that is influenced by muscle fatigue. This study examined the effects of creatine supplementation on explosive performance and the optimal individual PAP time during a set of complex training bouts. Thirty explosive athletes performed tests of back squat for one repetition maximum (1RM) strength and complex training bouts for determining the individual optimal timing of PAP, height and peak power of a counter movement jump before and after the supplementation. Subjects were assigned to a creatine or placebo group and then consumed 20 g of creatine or carboxymethyl cellulose per day for six days. After the supplementation, the 1RM strength in the creatine group significantly increased (p < 0.05). The optimal individual PAP time in the creatine group was also significant earlier than the pre-supplementation and post-supplementation of the placebo group (p < 0.05). There was no significant difference in jump performance between the groups. This study demonstrates that creatine supplementation improves maximal muscle strength and the optimal individual PAP time of complex training but has no effect on explosive performance. PMID:26959056

Velocity- and power-load relationships of the bench pull vs. bench press exercises.

PubMed

Sánchez-Medina, L; González-Badillo, J J; Pérez, C E; Pallarés, J G

2014-03-01

This study compared the velocity- and power-load relationships of the antagonistic upper-body exercises of prone bench pull (PBP) and bench press (BP). 75 resistance-trained athletes performed a progressive loading test in each exercise up to the one-repetition maximum (1RM) in random order. Velocity and power output across the 30-100% 1RM were significantly higher for PBP, whereas 1RM strength was greater for BP. A very close relationship was observed between relative load and mean propulsive velocity for both BP (R2=0.97) and PBP (R2=0.94) which enables us to estimate %1RM from velocity using the obtained prediction equations. Important differences in the load that maximizes power output (Pmax) and the power profiles of both exercises were found according to the outcome variable used: mean (MP), peak (PP) or mean propulsive power (MPP). When MP was considered, the Pmax load was higher (56% BP, 70% PBP) than when PP (37% BP, 41% PBP) or MPP (37% BP, 46% PBP) were used. For each variable there was a broad range of loads at which power output was not significantly different. The differing velocity- and power-load relationships between PBP and BP seem attributable to the distinct muscle architecture and moment arm levers involved in these exercises. © Georg Thieme Verlag KG Stuttgart · New York.

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.

Velocity loss as an indicator of neuromuscular fatigue during resistance training.

PubMed

Sánchez-Medina, Luis; González-Badillo, Juan José

2011-09-01

This study aimed to analyze the acute mechanical and metabolic response to resistance exercise protocols (REP) differing in the number of repetitions (R) performed in each set (S) with respect to the maximum predicted number (P). Over 21 exercise sessions separated by 48-72 h, 18 strength-trained males (10 in bench press (BP) and 8 in squat (SQ)) performed 1) a progressive test for one-repetition maximum (1RM) and load-velocity profile determination, 2) tests of maximal number of repetitions to failure (12RM, 10RM, 8RM, 6RM, and 4RM), and 3) 15 REP (S × R[P]: 3 × 6[12], 3 × 8[12], 3 × 10[12], 3 × 12[12], 3 × 6[10], 3 × 8[10], 3 × 10[10], 3 × 4[8], 3 × 6[8], 3 × 8[8], 3 × 3[6], 3 × 4[6], 3 × 6[6], 3 × 2[4], 3 × 4[4]), with 5-min interset rests. Kinematic data were registered by a linear velocity transducer. Blood lactate and ammonia were measured before and after exercise. Mean repetition velocity loss after three sets, loss of velocity pre-post exercise against the 1-m·s load, and countermovement jump height loss (SQ group) were significant for all REP and were highly correlated to each other (r = 0.91-0.97). Velocity loss was significantly greater for BP compared with SQ and strongly correlated to peak postexercise lactate (r = 0.93-0.97) for both SQ and BP. Unlike lactate, ammonia showed a curvilinear response to loss of velocity, only increasing above resting levels when R was at least two repetitions higher than 50% of P. Velocity loss and metabolic stress clearly differs when manipulating the number of repetitions actually performed in each training set. The high correlations found between mechanical (velocity and countermovement jump height losses) and metabolic (lactate, ammonia) measures of fatigue support the validity of using velocity loss to objectively quantify neuromuscular fatigue during resistance training.

Functional capacity improves in-line with neuromuscular performance after 12 weeks of non-linear periodization strength training in the elderly.

PubMed

Moura, Bruno Monteiro de; Sakugawa, Raphael Luiz; Orssatto, Lucas Bet da Rosa; de Lima, Luis Antonio Pereira; Pinto, Ronei Silveira; Walker, Simon; Diefenthaeler, Fernando

2017-12-06

While it is accepted that resistance training can improve functional capacity in older individuals, the neuromuscular source of this improvement has yet to be identified. This study investigated the link between improved neuromuscular performance and functional capacity after a 12-week resistance training period in untrained healthy older individuals. Fifteen older men and women (60-71 years) adhered to a 4-week control period, followed by 12 weeks of non-linear resistance training for the lower limbs. Maximum dynamic leg press strength (1-RM), maximum isometric knee extension torque and rate of torque development (RTD) were evaluated at - 4, 0, 4, 8, and 12 weeks, and muscle activity was assessed at 0, 4, 8, and 12 weeks. Functional capacity tests (chair rise, stair ascent and descent, and timed up and go) were performed at - 4, 0, and 12 weeks. No changes occurred during the control period, but the group increased their 1-RM strength (from 142 ± 53 to 198 ± 43 kg, p = 0.001), which was accompanied by an increase in vastus lateralis activation (p = 0.008) during the intervention. Increase was observed at all RTD time intervals at week 8 (p < 0.05). Significant improvements in all the functional capacity tests were observed at week 12 (p < 0.05). Despite the expected increase in strength, RTD, muscle activity, and functional capacity, there was no significant relationship between the changes in neuromuscular performance and functional capacity. While resistance training elicits various positive improvements in healthy older individuals, actual strength gain did not influence the gain in functional capacity. The present study highlights the exact cause that improved the functional capabilities during resistance training are currently unknown.

The Effects of Mental Imagery with Video-Modeling on Self-Efficacy and Maximal Front Squat Ability

PubMed Central

Buck, Daniel J. M.; Hutchinson, Jasmin C.; Winter, Christa R.; Thompson, Brian A.

2016-01-01

This study was designed to assess the effectiveness of mental imagery supplemented with video-modeling on self-efficacy and front squat strength (three repetition maximum; 3RM). Subjects (13 male, 7 female) who had at least 6 months of front squat experience were assigned to either an experimental (n = 10) or a control (n = 10) group. Subjects′ 3RM and self-efficacy for the 3RM were measured at baseline. Following this, subjects in the experimental group followed a structured imagery protocol, incorporating video recordings of both their own 3RM performance and a model lifter with excellent technique, twice a day for three days. Subjects in the control group spent the same amount of time viewing a placebo video. Following three days with no physical training, measurements of front squat 3RM and self-efficacy for the 3RM were repeated. Subjects in the experimental group increased in self-efficacy following the intervention, and showed greater 3RM improvement than those in the control group. Self-efficacy was found to significantly mediate the relationship between imagery and front squat 3RM. These findings point to the importance of mental skills training for the enhancement of self-efficacy and front squat performance.

The Effects of Mental Imagery with Video-Modeling on Self-Efficacy and Maximal Front Squat Ability.

PubMed

Buck, Daniel J M; Hutchinson, Jasmin C; Winter, Christa R; Thompson, Brian A

2016-04-14

This study was designed to assess the effectiveness of mental imagery supplemented with video-modeling on self-efficacy and front squat strength (three repetition maximum; 3RM). Subjects (13 male, 7 female) who had at least 6 months of front squat experience were assigned to either an experimental ( n = 10) or a control ( n = 10) group. Subjects' 3RM and self-efficacy for the 3RM were measured at baseline. Following this, subjects in the experimental group followed a structured imagery protocol, incorporating video recordings of both their own 3RM performance and a model lifter with excellent technique, twice a day for three days. Subjects in the control group spent the same amount of time viewing a placebo video. Following three days with no physical training, measurements of front squat 3RM and self-efficacy for the 3RM were repeated. Subjects in the experimental group increased in self-efficacy following the intervention, and showed greater 3RM improvement than those in the control group. Self-efficacy was found to significantly mediate the relationship between imagery and front squat 3RM. These findings point to the importance of mental skills training for the enhancement of self-efficacy and front squat performance.

Familiarization, validity and smallest detectable difference of the isometric squat test in evaluating maximal strength.

PubMed

Drake, David; Kennedy, Rodney; Wallace, Eric

2018-02-06

Isometric multi-joint tests are considered reliable and have strong relationships with 1RM performance. However, limited evidence is available for the isometric squat in terms of effects of familiarization and reliability. This study aimed to assess, the effect of familiarization, stability reliability, determine the smallest detectible difference, and the correlation of the isometric squat test with 1RM squat performance. Thirty-six strength-trained participants volunteered to take part in this study. Following three familiarization sessions, test-retest reliability was evaluated with a 48-hour window between each time point. Isometric squat peak, net and relative force were assessed. Results showed three familiarizations were required, isometric squat had a high level of stability reliability and smallest detectible difference of 11% for peak and relative force. Isometric strength at a knee angle of ninety degrees had a strong significant relationship with 1RM squat performance. In conclusion, the isometric squat is a valid test to assess multi-joint strength and can discriminate between strong and weak 1RM squat performance. Changes greater than 11% in peak and relative isometric squat performance should be considered as meaningful in participants who are familiar with the test.

The Relationship between Vitamin D and Muscle Size and Strength in Patients on Hemodialysis

PubMed Central

Gordon, Patricia L.; Sakkas, Giorgos K.; Doyle, Julie W.; Shubert, Tiffany; Johansen, Kirsten L.

2007-01-01

OBJECTIVE Vitamin D has various actions in skeletal muscle. The purpose of this study was to compare lower limb muscle size and strength in hemodialysis (HD) patients being treated with 1,25-dihydroxyvitamin D (calcitriol) or a 1,25-dihydroxyvitamin D analog (paricalcitol) to HD patients who were receiving none. DESIGN This was a retrospective cross-sectional study. SETTING Outpatient hemodialysis centers. PATIENTS HD patients receiving calcitriol or paricalcitol (active vitamin D) for control of secondary hyperparathyroidism (VitD, n = 49) were compared to HD patients who were not (n = 30). MAIN OUTCOME MEASURES Cross-sectional areas (CSA) of thigh and tibialis anterior muscles by magnetic resonance imaging (MRI), and three measures of strength; three-repetition maximum (3RM) for knee extension (isotonic), peak torque of knee extensors (isokinetic), and maximal voluntary contraction (MVC) of the ankle dorsiflexor muscles (isometric). RESULTS There were no differences in age, weight, dialysis vintage, or intact parathyroid hormone levels between the groups, although serum albumin was higher in the VitD group (p <0.05). Patients in the VitD group had larger thigh muscle CSA (p < 0.05) and were stronger across all strength measures (p< 0.05) after controlling for age and gender (ANCOVA). When all analyses were subsequently adjusted for serum albumin concentration, only the difference in 3RM knee extension strength lost significance. There were no significant differences in any measurements between patients who received calcitriol or paricalcitol. CONCLUSION Treatment with active vitamin D was associated with greater muscle size and strength in this cohort of HD patients. PMID:17971312

Strength and power predictors of sports speed.

PubMed

Cronin, John B; Hansen, Keir T

2005-05-01

For many sporting activities, initial speed rather than maximal speed would be considered of greater importance to successful performance. The purpose of this study was to identify the relationship between strength and power and measures of first-step quickness (5-m time), acceleration (10-m time), and maximal speed (30-m time). The maximal strength (3 repetition maximum [3RM]), power (30-kg jump squat, countermovement, and drop jumps), isokinetic strength measures (hamstring and quadriceps peak torques and ratios at 60 degrees .s(-1) and 300 degrees .s(-1)) and 5-m, 10-m, and 30-m sprint times of 26 part-time and full-time professional rugby league players (age 23.2 +/- 3.3 years) were measured. To examine the importance of the strength and power measures on sprint performance, a correlational approach and a comparison between means of the fastest and slowest players was used. The correlations between the 3RM, drop jump, isokinetic strength measures, and the 3 measures of sport speed were nonsignificant. Correlations between the jump squat (height and relative power output) and countermovement jump height and the 3 speed measures were significant (r = -0.43 to -0.66, p < 0.05). The squat and countermovement jump heights as well as squat jump relative power output were the only variables found to be significantly greater in the fast players. It was suggested that improving the power to weight ratio as well as plyometric training involving countermovement and loaded jump-squat training may be more effective for enhancing sport speed in elite players.

Eight-Week Vibration Training of the Elbow Flexors by Force Modulation: Effects on Dynamic and Isometric Strength.

PubMed

Xu, Lin; Cardinale, Marco; Rabotti, Chiara; Beju, Bogdan; Mischi, Massimo

2016-03-01

Vibration exercise (VE) has been suggested as an effective method to improve strength and power capabilities. However, the underlying mechanisms in response to VE are still unclear. A pulley-like VE system, characterized by sinusoidal force applications has been developed and tested for proof of concept in a previous study. The aim of this study was to evaluate the effects of such force modulation on elbow flexors strength and compare it with conventional methods. Forty subjects were randomly divided into 4 groups of 10: the vibration group (VG), the no-vibration group (NVG), the dumbbell group (DG), and the control group (CG). Biceps curl exercises were used to train the elbow flexors 2 times a week for 8 weeks. Subjects in the VG were trained using a ramp-up baseline with superimposed 30 Hz sinusoidal vibration whereas the subjects in the NVG were trained using the same baseline but without vibration. Subjects in the DG were trained using dumbbells, and the subjects in the CG were not trained. The isometric break force (IBF) and 1 repetition maximum (1RM) of the subject's dominant arm were assessed before and after the 8-week training period. The VG achieved 1RM improvement (22.7%) larger than the NVG (10.8%) and comparable with the DG (22.3%). Differences in IBF gains following the training period among the training groups were found to be not significant. Our results support the inclusion of the proposed VE in strength training programs aimed at improving dynamic strength on the elbow flexors.

A metronome for controlling the mean velocity during the bench press exercise.

PubMed

Moras, Gerard; Rodríguez-Jiménez, Sergio; Busquets, Albert; Tous-Fajardo, Julio; Pozzo, Marco; Mujika, Iñigo

2009-05-01

Lifting velocity may have a great impact on strength training-induced adaptations. The purpose of this study was to validate a method including a metronome and a measurement tape as inexpensive tools for the estimation of mean lifting velocity during the bench press exercise. Fifteen subjects participated in this study. After determining their one repetition maximum (1RM) load, we estimated the maximum metronome rhythm (R) that each subject could maintain in the concentric phase for loads of 40 and 60% of 1RM. To estimate R, the 3 repetitions with highest concentric power, as measured by means of a linear encoder, were selected, and their average duration was calculated and converted to lifting rhythm in beats per minute (bpm) for each subject. The range of motion was measured using a regular tape and kept constant during all exercises. Subjects were instructed to begin with the barbell at arm lengths and lower it in correspondence with the metronome beep. They subsequently performed 5 repetitions at 3 different rhythms relative to R (50, 70, and 90% R) for each training load (40 and 60% of 1RM). A linear encoder was attached to the bar and used as a criterion to measure the vertical displacement over time. For each rhythm, the mean velocity was calculated with the metronome (time) and the reference distance and compared with that recorded by the linear encoder. The SEM for velocity between both testing methods ranged from 0.02 to 0.05 m.s (coefficient of variation, 4.0-6.4%; Pearson's correlation, 0.8-0.95). The present results showed that the use of a metronome and a measurement tape may be a valid method to estimate the mean velocity of execution during the bench press exercise. This simple method could help coaches and athletes achieve their strength training goals, which are partly determined by lifting velocity.

Lactate Threshold as a Measure of Aerobic Metabolism in Resistance Exercise.

PubMed

Domínguez, Raúl; Maté-Muñoz, José Luis; Serra-Paya, Noemí; Garnacho-Castaño, Manuel Vicente

2018-02-01

In resistance training, load intensity is usually calculated as the percentage of a maximum repetition (1RM) or maximum number of possible repetitions (% of 1RM). Some studies have proposed a lactate threshold (LT) intensity as an optimal approach for concurrent training of cardiorespiratory endurance and muscle strength, as well as an alternative in resistance training. The objective of the present study was to analyze the results obtained in research evaluating the use of LT in resistance training. A keyword and search tree strategy identified 14 relevant articles in the Dialnet, Elsevier, Medline, Pubmed, Scopus and Web of Science databases. Based on the studies analyzed, the conclusion was that the LT in resistance exercises can be determined either by mathematical methods or by visual inspection of graphical plots. Another possibility is to measure the intensity at which LT might coincide with the first ventilatory threshold (VT1). Since performing an exercise session at one's LT intensity has been shown to accelerate the cardiorespiratory response and induce neuromuscular fatigue, this intensity could be used to set the training load in a resistance training program. © Georg Thieme Verlag KG Stuttgart · New York.

Pituitary-adrenal-gonadal responses to high-intensity resistance exercise overtraining.

PubMed

Fry, A C; Kraemer, W J; Ramsey, L T

1998-12-01

Weight-trained men [OT; n = 11; age = 22.0 +/- 0.9 (SE) yr] resistance trained daily at 100% one-repetition maximum (1-RM) intensity for 2 wk, resulting in 1-RM strength decrements and in an overtrained state. A control group (Con; n = 6; age = 23.7 +/- 2.4 yr) trained 1 day/wk at a low relative intensity (50% 1 RM). After 2 wk, the OT group exhibited slightly increased exercise-induced testosterone (preexercise = 26.5 +/- 1.3 nmol/l, postexercise = 29.1 +/- 5.9 nmol/l) and testosterone-to-cortisol ratio (preexercise = 0. 049 +/- 0.007 nmol/l, postexercise = 0.061 +/- 0.006 nmol/l) and decreased exercise-induced cortisol (preexercise = 656.1 +/- 98.1 nmol/l, postexercise = 503.1 +/- 39.7 nmol/l). Serum concentrations for growth hormone and plasma peptide F [preproenkephalin (107-140)] were similar for both groups throughout the overtraining period. This hormonal profile is distinctly different from what has been previously reported for other types of overtraining, indicating that high-relative-intensity resistance exercise overtraining may not be successfully monitered via circulating testosterone and cortisol. Unlike overtraining conditions with endurance athletes, altered resting concentrations of pituitary, adrenal, or gonadal hormones were not evident, and exercise-induced concentrations were only modestly affected.

Does combined strength training and local vibration improve isometric maximum force? A pilot study.

PubMed

Goebel, Ruben; Haddad, Monoem; Kleinöder, Heinz; Yue, Zengyuan; Heinen, Thomas; Mester, Joachim

2017-01-01

The aim of the study was to determine whether a combination of strength training (ST) and local vibration (LV) improved the isometric maximum force of arm flexor muscles. ST was applied to the left arm of the subjects; LV was applied to the right arm of the same subjects. The main aim was to examine the effect of LV during a dumbbell biceps curl (Scott Curl) on isometric maximum force of the opposite muscle among the same subjects. It is hypothesized, that the intervention with LV produces a greater gain in isometric force of the arm flexors than ST. Twenty-seven collegiate students participated in the study. The training load was 70% of the individual 1 RM. Four sets with 12 repetitions were performed three times per week during four weeks. The right arm of all subjects represented the vibration trained body side (VS) and the left arm served as the traditional trained body side (TTS). A significant increase of isometric maximum force in both body sides (Arms) occurred. VS, however, significantly increased isometric maximum force about 43% in contrast to 22% of the TTS. The combined intervention of ST and LC improves isometric maximum force of arm flexor muscles. III.

Efficacy and feasibility of a novel tri-modal robust exercise prescription in a retirement community: a randomized, controlled trial.

PubMed

Baker, Michael K; Kennedy, David J; Bohle, Philip L; Campbell, Deena S; Knapman, Leona; Grady, Jodie; Wiltshire, James; McNamara, Maria; Evans, William J; Atlantis, Evan; Fiatarone Singh, Maria A

2007-01-01

To test the feasibility and efficacy of current guidelines for multimodal exercise programs in older adults. Randomized, controlled trial. Retirement village. Thirty-eight subjects (14 men and 24 women) aged 76.6 +/- 6.1. A wait list control or 10 weeks of supervised exercise consisting of high-intensity (80% of one-repetition maximum (1RM)) progressive resistance training (PRT) 3 days per week, moderate-intensity (rating of perceived exertion 11 to 14/20) aerobic training 2 days per week, and progressive balance training 1 day per week. Blinded assessments of dynamic muscle strength (1RM), balance, 6-minute walk, gait velocity, chair stand, stair climb, depressive symptoms, self-efficacy, and habitual physical activity level. Higher baseline strength and psychological well-being were associated with better functional performance. Strength gains over 10 weeks averaged 39+/-31% in exercise, versus 21+/-24% in controls (P=.10), with greater improvements in hip flexion (P=.01), hip abduction (P=.02), and chest press (P=.04) in the exercise group. Strength adaptations were greatest in exercises in which the intended continuous progressive overload was achieved. Stair climb power (12.3+/-15%, P=.002) and chair stand time (-7.1+/-15%, P=.006) improved significantly and similarly in both groups. Reduction in depressive symptoms was significantly related to compliance (attendance rate r=-0.568, P=.009, PRT progression in loading r=-0.587, P=.02, and total volume of aerobic training r=-0.541, P=.01), as well as improvements in muscle strength (r=-0.498, P=.002). Robust physical and psychological adaptations to exercise are linked, although volumes and intensities of multiple exercise modalities sufficient to cause significant adaptation appear difficult to prescribe and adhere to simultaneously in older adults.

Vitamin C and E supplementation alters protein signalling after a strength training session, but not muscle growth during 10 weeks of training

PubMed Central

Paulsen, G; Hamarsland, H; Cumming, K T; Johansen, R E; Hulmi, J J; Børsheim, E; Wiig, H; Garthe, I; Raastad, T

2014-01-01

This study investigated the effects of vitamin C and E supplementation on acute responses and adaptations to strength training. Thirty-two recreationally strength-trained men and women were randomly allocated to receive a vitamin C and E supplement (1000 mg day−1 and 235 mg day−1, respectively), or a placebo, for 10 weeks. During this period the participants’ training involved heavy-load resistance exercise four times per week. Muscle biopsies from m. vastus lateralis were collected, and 1 repetition maximum (1RM) and maximal isometric voluntary contraction force, body composition (dual-energy X-ray absorptiometry), and muscle cross-sectional area (magnetic resonance imaging) were measured before and after the intervention. Furthermore, the cellular responses to a single exercise session were assessed midway in the training period by measurements of muscle protein fractional synthetic rate and phosphorylation of several hypertrophic signalling proteins. Muscle biopsies were obtained from m. vastus lateralis twice before, and 100 and 150 min after, the exercise session (4 × 8RM, leg press and knee-extension). The supplementation did not affect the increase in muscle mass or the acute change in protein synthesis, but it hampered certain strength increases (biceps curl). Moreover, increased phosphorylation of p38 mitogen-activated protein kinase, Extracellular signal-regulated protein kinases 1 and 2 and p70S6 kinase after the exercise session was blunted by vitamin C and E supplementation. The total ubiquitination levels after the exercise session, however, were lower with vitamin C and E than placebo. We concluded that vitamin C and E supplementation interfered with the acute cellular response to heavy-load resistance exercise and demonstrated tentative long-term negative effects on adaptation to strength training. PMID:25384788

Comparison of In-Season-Specific Resistance vs. A Regular Throwing Training Program on Throwing Velocity, Anthropometry, and Power Performance in Elite Handball Players.

PubMed

Hermassi, Souhail; van den Tillaar, Roland; Khlifa, Riadh; Chelly, Mohamed Souhaiel; Chamari, Karim

2015-08-01

The purpose of this study was to compare the effect of a specific resistance training program (throwing movement with a medicine ball) with that of regular training (throwing with regular balls) on ball velocity, anthropometry, maximal upper-body strength, and power. Thirty-four elite male team handball players (age: 18 ± 0.5 years, body mass: 80.6 ± 5.5 kg, height: 1.80 ± 5.1 m, body fat: 13.4 ± 0.6%) were randomly assigned to 1 of the 3 groups: control (n = 10), resistance training group (n = 12), or regular throwing training group (n = 12). Over the 8-week in season, the athletes performed 3 times per week according to an assigned training program alongside their normal team handball training. One repetition maximum (1RM) bench press and 1RM pullover scores assessed maximal arm strength. Anthropometry was assessed by body mass, fat percentage, and muscle volumes of upper body. Handball throwing velocity was measured by a standing throw, a throw with run, and a jump throw. Power was measured by measuring total distance thrown by a 3-kg medicine ball overhead throw. Throwing ball velocity, maximal strength, power, and muscle volume increases for the specific resistance training group after the 8 weeks of training, whereas only maximal strength, muscle volume and power and in the jump throw increases were found for the regular throwing training group. No significant changes for the control group were found. The current findings suggest that elite male handball players can improve ball velocity, anthropometrics, maximal upper-body strength, and power during the competition season by implementing a medicine ball throwing program.

Effects of protein supplementation on muscular performance and resting hormonal changes in college football players.

PubMed

Hoffman, Jay R; Ratamess, Nicholas A; Kang, Jie; Falvo, Michael J; Faigenbaum, Avery D

2007-01-01

The effect of protein supplementation on athletic performance and hormonal changes was examined in 21 experienced collegiate strength/power athletes participating in a 12-week resistance training program. Subjects were randomly assigned to either a protein supplement (PR; n = 11) or a placebo (PL; n = 10) group. During each testing session subjects were assessed for strength (one repetition maximum [1-RM] bench press and squat), power (Wingate anaerobic power test) and body composition. Resting blood samples were analyzed at weeks 0 (PRE), 6 (MID) and 12 (POST) for total testosterone, cortisol, growth hormone, and IGF-1. No difference was seen in energy intake between PR and PL (3034 ± 209 kcal and 3130 ± 266 kcal, respectively), but a significant difference in daily protein intake was seen between PR (2.00 g·kg body mass[BM](-1)·d(-1)) and PL (1.24 g·kgBM(-1)·d(-1)). A greater change (p < 0.05) in the ∆ 1-RM squat was seen in PR (23.5 ± 13.6 kg) compared to PL (9.1 ± 11.9 kg). No other significant strength or power differences were seen between the groups. Cortisol concentrations were significantly lower at MID for PL and this difference was significantly different than PR. No significant changes were noted in resting growth hormone or IGF-1 concentrations in either group. Although protein supplementation appeared to augment lower body strength development, similar upper body strength, anaerobic power and lean tissue changes do not provide clear evidence supporting the efficacy of a 12-week protein supplementation period in experienced resistance trained athletes. Key pointsCollegiate strength/power athletes may not meet daily recommended energy or protein needs.When athletes are provided a protein supplement they appear to meet the recommended daily protein intake for strength/power athletes.Protein supplementation did augment lower body strength development in experienced strength/power athletes.Results of upper body strength, anaerobic power and lean tissue changes did not support the efficacy of a 12-week protein supplementation period in experienced resistance trained athletes.

Contributing factors to performance of a medicine ball explosive power test: a comparison between jump and nonjump athletes.

PubMed

Stockbrugger, Barry A; Haennel, Robert G

2003-11-01

The present study examined the factors contributing to performance of a backward overhead medicine ball throw (B-MBT) across 2 types of athletes. Twenty male volleyball players (jump athletes) and 20 wrestlers (nonjump athletes) were evaluated on 4 measures of power, including B-MBT, chest medicine ball throw (C-MBT), countermovement vertical jump (CMJ), and power index (PI). The athletes also completed 3 measures of strength: a 1-repetition-maximum (1RM) bench press (BP), a 1RM leg press (LP), and combined BP + LP strength. Jump athletes demonstrated greater absolute scores for CMJ, C-MBT, and B-MBT (p < 0.05), whereas nonjump athletes demonstrated greater strength scores for BP and for BP + LP (p < 0.05). When performances were examined on a relative basis, jump athletes achieved superior scores for C-MBT (p < 0.05), whereas nonjump athletes had greater scores for BP, LP, and BP + LP (p < 0.05). For both groups, B-MBT had strong correlations with PI (r = 0.817 [jump] and 0.917 [nonjump]), whereas for C-MBT, only nonjump athletes demonstrated a strong correlation (r = 0.842). When expressed in relative terms, B-MBT was strongly correlated with C-MBT (r = 0.762 [jump] and 0.835 [nonjump]) and CMJ (r = 0.899 [jump] and 0.945 [nonjump]). Only nonjump athletes demonstrated strong correlations with strength for absolute LP (r = 0.801) and BP + LP (r = 0.810) strength. The interaction of upper- and lower-body strength and power in the performance of a B-MBT appears complex, with the contributing factors differing for athletes with divergent skill sets and performance demands.

Prior sprint cycling did not enhance training adaptation, but resting salivary hormones were related to workout power and strength.

PubMed

Crewther, Blair T; Lowe, Tim; Weatherby, Robert P; Gill, Nicholas

2009-04-01

This study examined the effect of cycle sprints as a potentiating stimulus for power and strength adaptation in semi-elite athletes. Eighteen rugby players were assigned into training groups that completed either a 40-s cycle sprint (T(SPRINT)) or rested (T(CONTROL)) before each workout (n = 6-8) of a 4-week programme. Squat jump (SJ) peak power (PP) and mean power (MP), and box squat (BS) one repetition maximum (1RM) strength were assessed every workout. Saliva was collected across each workout and assayed for testosterone (Sal-T) and cortisol (Sal-C). The T(SPRINT) and T(CONTROL) groups both showed significant improvements in SJ PP (8.2 +/- 2.9 vs. 11.9 +/- 3.6%), SJ MP (11.8 +/- 2.6 vs. 18.6 +/- 4.8%) and BS 1RM (20.5 +/- 2.6 vs. 23.2 +/- 1.3%), respectively. However, there were no group differences in training adaptation, workout performance or the workout hormonal responses. As a combined group (all players), significant relationships were demonstrated between resting Sal-T and/or Sal-C concentrations and absolute SJ power (r = 0.20-0.30) and BS strength (r = 0.36-0.44) across all workouts. For individual players, the respective relationships with SJ power (r = 0.22-0.42) and BS strength (r = 0.41-0.49) were, on average, found to be stronger. In conclusion, leg workouts performed with or without prior cycle sprints can produce similar power and strength improvements in semi-elite rugby players. Resting salivary hormone concentrations appear important for workout performance, especially for individuals, thereby potentially moderating training adaptation.

Functional and Muscle-Size Effects of Flywheel Resistance Training with Eccentric-Overload in Professional Handball Players.

PubMed

Maroto-Izquierdo, Sergio; García-López, David; de Paz, José A

2017-12-01

The aim of the study was to analyse the effects of 6 week (15 sessions) flywheel resistance training with eccentric-overload (FRTEO) on different functional and anatomical variables in professional handball players. Twenty-nine athletes were recruited and randomly divided into two groups. The experimental group (EXP, n = 15) carried out 15 sessions of FRTEO in the leg-press exercise, with 4 sets of 7 repetitions at a maximum-concentric effort. The control group (CON, n = 14) performed the same number of training sessions including 4 sets of 7 maximum repetitions (7RM) using a weight-stack leg-press machine. The results which were measured included maximal dynamic strength (1RM), muscle power at different submaximal loads (PO), vertical jump height (CMJ and SJ), 20 m sprint time (20 m), T-test time (T-test), and Vastus-Lateralis muscle (VL) thickness. The results of the EXP group showed a substantially better improvement (p < 0.05-0.001) in PO, CMJ, 20 m, T-test and VL, compared to the CON group. Moreover, athletes from the EXP group showed significant improvements concerning all the variables measured: 1RM (ES = 0.72), PO (ES = 0.42 - 0.83), CMJ (ES = 0.61), SJ (ES = 0.54), 20 m (ES = 1.45), T-test (ES = 1.44), and VL (ES = 0.63 - 1.64). Since handball requires repeated short, explosive effort such as accelerations and decelerations during sprints with changes of direction, these results suggest that FRTEO affects functional and anatomical changes in a way which improves performance in well-trained professional handball players.

The effects of ageing on respiratory muscle function and performance in older adults.

PubMed

Watsford, Mark L; Murphy, Aron J; Pine, Matthew J

2007-02-01

The reduced physiological capacity evident with ageing may affect the ability to perform many tasks, potentially affecting quality of life. Previous research has clearly demonstrated the reduced capacity of the respiratory system with ageing and described the effect that habitual physical activity has upon this decline. This research aimed to examine the influence of age on respiratory muscle (RM) function and the relationship between RM function and physical performance within the Australian population. Seventy-two healthy older adults (50-79 years) were divided into males (n=36) and females (n=36) and examined for pulmonary function, RM strength, inspiratory muscle endurance (IME) and 1.6 km walking performance. There were no significant age by gender effects for any variables; however, ageing was significantly related to reduced RM function and walking capacity within each gender. Furthermore, regression analysis showed that the RM strength could be predicted from age. Partial correlations controlling for age indicated that expiratory muscle strength was significantly related to walking performance in males (p=0.04), whilst IME contributed significantly to walking performance in all participants. These within-gender effects and relationships indicate that RM strength is an important physiological variable to maintain in the older population, as it may be related to functional ability.

Effect of resistance training with vibration and compression on the formation of muscle and bone.

PubMed

Zinner, Christoph; Baessler, Bettina; Weiss, Kilian; Ruf, Jasmine; Michels, Guido; Holmberg, Hans-Christer; Sperlich, Billy

2017-12-01

In this study we investigated the effects of resistance training with vibration in combination with leg compression to restrict blood flow on strength, muscle oxygenation, muscle mass, and bone formation. Twelve participants were tested before and after 12 weeks of resistance training with application of vibration (VIBRA; 1-2 mm, 30 Hz) to both legs and compression (∼35 mm Hg, VIBRA+COMP) to only 1 leg. VIBRA+COMP and VIBRA improved 1 repetition maximum (1-RM), increased the number of repetitions preceding muscle exhaustion, enhanced cortical bone mass, and lowered the mass and fat fraction in the thigh, with no changes in total muscle mass. The mass of cancellous bone decreased to a similar extent after VIBRA and VIBRA+COMP. Resistance training with VIBRA+COMP and VIBRA improved 1-RM, increased the number of repetitions preceding muscular exhaustion, and enhanced formation of cortical bone, with no alteration of muscle mass. Muscle Nerve 56: 1137-1142, 2017. © 2017 Wiley Periodicals, Inc.

The effects of adding single-joint exercises to a multi-joint exercise resistance training program on upper body muscle strength and size in trained men.

PubMed

de França, Henrique Silvestre; Branco, Paulo Alexandre Nordeste; Guedes Junior, Dilmar Pinto; Gentil, Paulo; Steele, James; Teixeira, Cauê Vazquez La Scala

2015-08-01

The aim of this study was compare changes in upper body muscle strength and size in trained men performing resistance training (RT) programs involving multi-joint plus single-joint (MJ+SJ) or only multi-joint (MJ) exercises. Twenty young men with at least 2 years of experience in RT were randomized in 2 groups: MJ+SJ (n = 10; age, 27.7 ± 6.6 years) and MJ (n = 10; age, 29.4 ± 4.6 years). Both groups trained for 8 weeks following a linear periodization model. Measures of elbow flexors and extensors 1-repetition maximum (1RM), flexed arm circumference (FAC), and arm muscle circumference (AMC) were taken pre- and post-training period. Both groups significantly increased 1RM for elbow flexion (4.99% and 6.42% for MJ and MJ+SJ, respectively), extension (10.60% vs 9.79%, for MJ and MJ+SJ, respectively), FAC (1.72% vs 1.45%, for MJ and MJ+SJ, respectively), and AMC (1.33% vs 3.17% for MJ and MJ+SJ, respectively). Comparison between groups revealed no significant difference in any variable. In conclusion, 8 weeks of RT involving MJ or MJ+SJ resulted in similar alterations in muscle strength and size in trained participants. Therefore, the addition of SJ exercises to a RT program involving MJ exercises does not seem to promote additional benefits to trained men, suggesting MJ-only RT to be a time-efficient approach.

Effect of instructions on EMG during the bench press in trained and untrained males.

PubMed

Daniels, Rebecca J; Cook, Summer B

2017-10-01

Strength and rehabilitation professionals strive to emphasize certain muscles used during an exercise and it may be possible to alter muscle recruitment strategies with varying instructions. This study aimed to determine whether resistance trained and untrained males could selectively activate the pectoralis major or triceps brachii during the bench press according to various instructions. This study included 13 trained males (21.5±2.9years old, 178.7±7.0cm, 85.7±10.7kg) and 12 untrained males (20.3±1.6years old, 178.8±9.4cm, 74.6±17.3kg). Participants performed a bench press one-repetition maximum (1-RM) test, 3 uninstructed repetitions at 80% 1-RM and two more sets of three repetitions with instructions to isolate the chest or arm muscles. Electromyography (EMG) was obtained from the pectoralis major, anterior deltoid, and the long head and short head of the triceps brachii. Maximum EMG activity normalized to 1-RM for each muscle was averaged over the three repetitions for each set and compared between the uninstructed, chest-instructed and arm-instructed conditions among the groups. The trained participants had a greater 1-RM (126.2±30.6kg) than the untrained participants (61.6±14.8kg) (P<0.01). EMG activity was not different between the groups for any of the instructions (P>0.05). When the group data was combined, short head of the triceps activity was significantly lower in the chest instruction (80.1±19.3%) when compared to the uninstructed (85.6±23.3%; P=0.01) and arm-instructed (86.0±23.2; P=0.01) conditions. It can be concluded that instructions can affect muscle activation during the bench press, and this is not dependent on training status. Copyright © 2017 Elsevier B.V. All rights reserved.

CNTF 1357 G -> A polymorphism and the muscle strength response to resistance training.

PubMed

Walsh, Sean; Kelsey, Bethany K; Angelopoulos, Theodore J; Clarkson, Priscilla M; Gordon, Paul M; Moyna, Niall M; Visich, Paul S; Zoeller, Robert F; Seip, Richard L; Bilbie, Steve; Thompson, Paul D; Hoffman, Eric P; Price, Thomas B; Devaney, Joseph M; Pescatello, Linda S

2009-10-01

The present study examined associations between the ciliary neurotrophic factor (CNTF) 1357 G --> A polymorphism and the muscle strength response to a unilateral, upper arm resistance-training (RT) program among healthy, young adults. Subjects were 754 Caucasian men (40%) and women (60%) who were genotyped and performed a training program of the nondominant (trained) arm with the dominant (untrained) arm as a comparison. Peak elbow flexor strength was measured with one repetition maximum, isometric strength with maximum voluntary contraction, and bicep cross-sectional area with MRI in the trained and untrained arms before and after training. Women with the CNTF GG genotype gained more absolute isometric strength, as measured by MVC (6.5 +/- 0.3 vs. 5.2 +/- 0.5 kg), than carriers of the CNTF A1357 allele in the trained arm pre- to posttraining (P < 0.05). No significant associations were seen in men. Women with the CNTF GG genotype gained more absolute dynamic (1.0 +/- 0.1 vs. 0.6 +/- 0.1 kg) and allometric (0.022 +/- 0.0 vs. 0.015 +/- 0.0 kg/kg(-0.67)) strength, as measured by 1 RM, than carriers of the CNTF A1357 allele in the untrained arm pre- to posttraining (P < 0.05). No significant associations were seen in men. No significant associations, as measured by cross-sectional area, were seen in men or women. The CNTF 1357 G --> A polymorphism explains only a small portion of the variability in the muscle strength response to training in women.

Effects of a 6-Week Bench Press Program Using the Freak Bar in a Sample of Collegiate Club Powerlifters.

PubMed

Ghigiarelli, Jamie J; Pelton, Luke M; Gonzalez, Adam M; Fulop, Andras M; Gee, Joshua Y; Sell, Katie M

2018-04-01

Ghigiarelli, JJ, Pelton, LM, Gonzalez, AM, Fulop, AM, Gee, JY, and Sell, KM. Effects of a 6-week bench press program using the freak bar in a sample of collegiate club powerlifters. J Strength Cond Res 32(4): 938-949, 2018-Powerlifters train using specialty bars for unstable load (UL) training. For the bench press, the acute effects of UL are mixed, with few studies that examine training interventions. The purpose of this study was to examine the effects of a 6-week bench press training program that uses the Freak Bar (FB) as compared to a traditional barbell (TB) on maximum bench press, peak force, and peak impulse. Seven men and 3 women (21 ± 2.0 years, 172.2 ± 2.9 cm, and 95.3 ± 20.3 kg) were required to bench press 2 days per week as part of a structured program. On the second bench press day, the FB and TB groups performed 3-position pause bench presses at 60-70% one repetition maximum (1RM). One repetition maximum, peak force, and peak impulse were measured before test and after test after the 6-week program. Peak force and peak impulse were tested at 3 bench positions, including the presticking, sticking, and poststicking points, defined by the distance of the barbell from the chest. Posttraining 1RM for the FB group and TB group increased 6.7% (6.78 ± 1.6 kg, p = 0.006) and 4.3% (4.5 ± 2.7 kg, p = 0.23), respectively, with no significant differences between the groups (p = 0.589, ηp = 0.044). There were no significant differences between the groups at each bench position for peak force (p = 0.606) or peak impulse (p = 0.542). Freak Bar can be an alternative for improving maximum strength and peak force but is not significantly better than TB training when performing the 3-position pause bench press.

Resistance training status and effectiveness of low frequency resistance training on upper-body strength and power in highly trained soccer players.

PubMed

Hertzog, Maxime; Rumpf, Michael Clemens; Hader, Karim

2017-08-26

Soccer is classified as a contact/collision sport with many player-to-player duels. Winning these duels, shielding the ball or fending off an opponent requires upper-body strength and power. Therefore this study aimed, a) to examine the time-related effect of an upper-body RT on maximal strength and power changes in highly trained soccer players, b) to investigate if the resistance-training (RT) status influences these changes throughout a competitive season. Twenty-eight soccer players participated in this study and were divided into an untrained (UG) and a trained (TG) group, according to their RT status. Both groups performed the same upper-body RT once a week, over 30 weeks. Maximal strength (1RM) and maximal power (MP) were assessed before, during and after the competitive season. Both groups significantly improved 1RM and MP over the entire competitive season, with a moderate (TG, 13%) to very large (UG, 21%) magnitude in 1RM and with a small (TG, 8%) to moderate (UG, 13%) magnitude in MP. After the initial 10 weeks of RT, UG presented significant and slightly (1RM) to moderately (MP) greater improvements than TG. For all other time intervals, the between-groups changes in 1RM were rated as similar. For the last 20 weeks of the RT, the change in MP was significantly lower for UG compared to TG. One upper-body RT-session per week will provide sufficient stimulus to enable an almost certain improvement in strength and power throughout a competitive season for all players disregarding their initial RT status.

Isometric Mid-Thigh Pull Correlates With Strength, Sprint, and Agility Performance in Collegiate Rugby Union Players.

PubMed

Wang, Ran; Hoffman, Jay R; Tanigawa, Satoru; Miramonti, Amelia A; La Monica, Michael B; Beyer, Kyle S; Church, David D; Fukuda, David H; Stout, Jeffrey R

2016-11-01

Wang, R, Hoffman, JR, Tanigawa, S, Miramonti, AA, La Monica, MB, Beyer, KS, Church, DD, Fukuda, DH, and Stout, JR. Isometric mid-thigh pull correlates with strength, sprint, and agility performance in collegiate rugby union players. J Strength Cond Res 30(11): 3051-3056, 2016-The purpose of this investigation was to examine the relationships between isometric mid-thigh pull (IMTP) force and strength, sprint, and agility performance in collegiate rugby union players. Fifteen members of a champion-level university's club rugby union team (mean ± SD: 20.67 ± 1.23 years, 1.78 ± 0.06 m, and 86.51 ± 14.18 kg) participated in this investigation. One repetition maximum (1RM) squat, IMTP, speed (40 m sprint), and agility (proagility test and T-test) were performed during 3 separate testing sessions. Rate of force development (RFD) and force output at 30, 50, 90, 100, 150, 200, and 250 milliseconds of IMTP, as well as the peak value were determined. Pearson product-moment correlation analysis was used to examine the relationships between these measures. Performance in the 1RM squat was significantly correlated to the RFD between 90 and 250 milliseconds from the start of contraction (r's ranging from 0.595 to 0.748), and peak force (r = 0.866, p ≤ 0.05). One repetition maximum squat was also correlated to force outputs between 90 and 250 milliseconds (r's ranging from 0.757 to 0.816, p ≤ 0.05). Sprint time over the first 5 m in the 40 m sprint was significantly (p ≤ 0.05) correlated with peak RFD (r = -0.539) and RFD between 30 and 50 milliseconds (r's = -0.570 and -0.527, respectively). Time for the proagility test was correlated with peak RFD (r = -0.523, p ≤ 0.05) and RFD between 30 and 100 milliseconds (r's ranging from -0.518 to -0.528, p's < 0.05). Results of this investigation indicate that IMTP variables are significantly associated with strength, agility, and sprint performance. Future studies should examine IMTP as a potential tool to monitor athletic performance during the daily training of rugby union players.

Using growth and arrest of Richtmyer-Meshkov instabilities and Lagrangian simulations to study high-rate material strength

NASA Astrophysics Data System (ADS)

Prime, M. B.; Vaughan, D. E.; Preston, D. L.; Buttler, W. T.; Chen, S. R.; Oró, D. M.; Pack, C.

2014-05-01

Experiments applying a supported shock through mating surfaces (Atwood number = 1) with geometrical perturbations have been proposed for studying strength at strain rates up to 107/s using Richtmyer-Meshkov (RM) instabilities. Buttler et al. recently reported experimental results for RM instability growth in copper but with an unsupported shock applied by high explosives and the geometrical perturbations on the opposite free surface (Atwood number = -1). This novel configuration allowed detailed experimental observation of the instability growth and arrest. We present results and interpretation from numerical simulations of the Buttler RM instability experiments. Highly-resolved, two-dimensional simulations were performed using a Lagrangian hydrocode and the Preston-Tonks-Wallace (PTW) strength model. The model predictions show good agreement with the data. The numerical simulations are used to examine various assumptions previously made in an analytical model and to estimate the sensitivity of such experiments to material strength.

Effect of low-intensity resistance training with heat stress on the HSP72, anabolic hormones, muscle size, and strength in elderly women.

PubMed

Yoon, Sung Jin; Lee, Moon Jin; Lee, Hyo Min; Lee, Jin Seok

2017-10-01

Several recent studies have reported that heat stress stimulates the activation of heat shock protein 72 (HSP72), leading to an increase in muscle synthesis. Some studies suggested that low-intensity resistance training combined with heat stress could improve muscle size and strength. This study aimed to identify the effect of low-intensity resistance training with heat stress over 12 weeks on the HSP72, anabolic hormones, muscle size, and strength in elderly women. The subjects were physically healthy women of 65-75 years, who were randomly assigned to one of three groups: a low-intensity resistance training with heating sheet group (HRT group, n = 8), a moderate-intensity resistance training (RT group, n = 6), and a heating sheet group (HEAT group, n = 7). Computed tomography scans, 1-repetition maximum (1RM), and blood samples were taken pre- and post-training. The HSP72 did not vary significantly between the different groups and times. The IGF-1 and 1RM had significantly increased in all three groups after the training (respectively, p < 0.05). Moreover, the cross-sectional area (CSA) of the quadriceps showed a significantly greater increase in the HRT group than in the HEAT group (p < 0.05). We found that low-intensity training with heat stress stimulated the anabolic hormones of elderly women, improving their muscle strength and hypertrophy. We believe that low-intensity training with heat stress is an effective way to prevent muscle atrophy and to improve muscle strength in elderly women.

Low dynamic muscle strength and its associations with fatigue, functional performance, and quality of life in premenopausal patients with systemic lupus erythematosus and low disease activity: a case–control study

PubMed Central

2013-01-01

Background The purpose of the present study was to compare dynamic muscle strength, functional performance, fatigue, and quality of life in premenopausal systemic lupus erythematosus (SLE) patients with low disease activity versus matched-healthy controls and to determine the association of dynamic muscle strength with fatigue, functional performance, and quality of life in SLE patients. Methods We evaluated premenopausal (18–45 years) SLE patients with low disease activity (Systemic lupus erythematosus disease activity index [SLEDAI]: mean 1.5 ± 1.2). The control (n = 25) and patient (n = 25) groups were matched by age, physical characteristics, and the level of physical activities in daily life (International Physical Activity Questionnaire IPAQ). Both groups had not participated in regular exercise programs for at least six months prior to the study. Dynamic muscle strength was assessed by one-repetition maximum (1-RM) tests. Functional performance was assessed by the Timed Up and Go (TUG), in 30-s test a chair stand and arm curl using a 2-kg dumbbell and balance test, handgrip strength and a sit-and-reach flexibility test. Quality of life (SF-36) and fatigue were also measured. Results The SLE patients showed significantly lower dynamic muscle strength in all exercises (leg press 25.63%, leg extension 11.19%, leg curl 15.71%, chest press 18.33%, lat pulldown 13.56%, 1-RM total load 18.12%, P < 0.001-0.02) compared to the controls. The SLE patients also had lower functional performance, greater fatigue and poorer quality of life. In addition, fatigue, SF-36 and functional performance accounted for 52% of the variance in dynamic muscle strength in the SLE patients. Conclusions Premenopausal SLE patients with low disease activity showed lower dynamic muscle strength, along with increased fatigue, reduced functional performance, and poorer quality of life when compared to matched controls. PMID:24011222

Time-divided ingestion pattern of casein-based protein supplement stimulates an increase in fat-free body mass during resistance training in young untrained men.

PubMed

Burk, Andres; Timpmann, Saima; Medijainen, Luule; Vähi, Mare; Oöpik, Vahur

2009-06-01

We hypothesized that during prolonged resistance training, time-divided ingestion pattern of casein-based protein supplement is of superior efficiency in comparison with the ingestion of the same supplement immediately before each training session. In a crossover study, 13 men aged 18 to 19 years were evaluated during 2 well-controlled, 8-week training and supplementation periods. In the time-focused supplementation regimen (TFR), the subjects consumed the supplement in the morning and in the afternoon, immediately before the training session. Time-divided supplementation regimen (TDR) included 1 morning dose, whereas the second dose was ingested in the evening, 5 hours after training. The daily dose of the supplement contained approximately 70 g of protein (82% casein) and less than 1 g of carbohydrate and fat. Body mass, body composition (dual-energy x-ray absorptiometry scanned), and one-repetition maximum (1RM) for bench press and squat were determined at the beginning and at the end of both 8-week training and supplementation periods. Training produced a significant increase in 1RM strength both in the bench press (9.4% and 7.2%) and the squat exercise (10.7% and 17.8%) in the TFR and TDR, respectively, with no differences between the supplementation regimens. Fat-free mass increased from 62.4 +/- 1.2 to 63.5 +/- 1.3 kg (P = .046) with TDR, whereas no change was evident with TFR. The increase in 1RM strength in the squat exercise was related to the increase in fat-free mass in TDR (r = 0.569; P = .041). These findings may have practical implications for the timing of ingestion of protein supplements to enhance the efficacy of resistance training.

Myostatin and follistatin polymorphisms interact with muscle phenotypes and ethnicity.

PubMed

Kostek, Matthew A; Angelopoulos, Theodore J; Clarkson, Priscilla M; Gordon, Paul M; Moyna, Niall M; Visich, Paul S; Zoeller, Robert F; Price, Thomas B; Seip, Richard L; Thompson, Paul D; Devaney, Joseph M; Gordish-Dressman, Heather; Hoffman, Eric P; Pescatello, Linda S

2009-05-01

We examined associations among myostatin (MSTN) 2379 A > G and 163 G > A and follistatin (FST) -5003 A > T and -833 G > T single nucleotide polymorphisms (SNP) on the muscle size and the strength response to resistance training (RT). Subjects (n = 645, age = 24.1 +/- 0.2 yr, body mass index [BMI] = 24.2 +/- 0.2 kg x m(-2)) self-disclosed themselves as Caucasian (78.9%), African American (3.6%), Asian (8.4%), Hispanic (5.0%), or Other (4.2%). They were genotyped for MSTN 2379 A > G (n = 645), MSTN 163 G > A (n = 639), FST -5003 A > T (n = 580), and FST -833 G > T (n = 603). We assessed dynamic (one repetition maximum [1RM]) and isometric (maximum voluntary contraction [MVC]) muscle strength and size (cross-sectional area [CSA]) of the elbow flexors before and after 12 wk of unilateral upper-arm RT. Repeated-measures ANCOVA tested associations among genetic variants and muscle phenotypes with age and BMI as covariates. Baseline MVC was greater among African Americans who were carriers of the MSTN G(2379) allele (AG/GG, n = 15) than the A2379A homozygotes (n = 8; 64.2 +/- 6.8 vs 49.8 +/- 8.7 kg). African Americans who were carriers of the FST T(-5003) allele (n = 12) had greater baseline 1RM (11.9 +/- 0.7 vs 8.8 +/- 0.5 kg) and CSA (24.4 +/- 1.3 vs 19.1 +/- 1.2 cm(2)) than African Americans with the A-5003A genotype (n = 14; P < 0.05). No MSTN or FST genotype and muscle phenotype associations were found among the other ethnic groups (P >or= 0.05). MSTN 2379 A > G and FST -5003 A > T were associated with baseline muscle strength and size among African Americans only. These ethnic-specific associations are hypothesis generating and should be confirmed in a larger sample of African Americans.

Exercise prescription to reverse frailty.

PubMed

Bray, Nick W; Smart, Rowan R; Jakobi, Jennifer M; Jones, Gareth R

2016-10-01

Frailty is a clinical geriatric syndrome caused by physiological deficits across multiple systems. These deficits make it challenging to sustain homeostasis required for the demands of everyday life. Exercise is likely the best therapy to reverse frailty status. Literature to date suggests that pre-frail older adults, those with 1-2 deficits on the Cardiovascular Health Study-Frailty Phenotype (CHS-frailty phenotype), should exercise 2-3 times a week, for 45-60 min. Aerobic, resistance, flexibility, and balance training components should be incorporated but resistance and balance activities should be emphasized. On the other hand, frail (CHS-frailty phenotype ≥ 3 physical deficits) older adults should exercise 3 times per week, for 30-45 min for each session with an emphasis on aerobic training. During aerobic, balance, and flexibility training, both frail and pre-frail older adults should work at an intensity equivalent to a rating of perceived exertion of 3-4 ("somewhat hard") on the Borg CR10 scale. Resistance-training intensity should be based on a percentage of 1-repetition estimated maximum (1RM). Program onset should occur at 55% of 1RM (endurance) and progress to higher intensities of 80% of 1RM (strength) to maximize functional gains. Exercise is the medicine to reverse or mitigate frailty, preserve quality of life, and restore independent functioning in older adults at risk of frailty.

Catalysis by Methylamine Dehydrogenase and Electron Transfer to Amicyanin and Cytochrome C(551I) from Paracoccus Denitrificans.

NASA Astrophysics Data System (ADS)

Brooks, Harold Burns

1995-01-01

The quinoprotein methylamine dehydrogenase (MADH), a type I copper protein, amicyanin, and cytochrome c _{55li} form a physiologic ternary complex (Chen et al. (1994) Science 264, 86-90) in which electrons are transferred from tryptophan tryptophylquinone to copper to heme. The reduction of MADH by rm H_3- and rm D_3 -methylamine, the reoxidation of MADH by amicyanin, and the reduction of cytochrome c_{55li } by reduced amicyanin in the presence of MADH have been studied by stopped-flow spectroscopy. When rm CD_3NH_2 was used as a substrate for MADH a deuterium kinetic isotope effect of 17.2 was measured for the hydrogen abstraction step. The maximum deuterium kinetic isotope effect that was measured in steady-state kinetic experiments was 3.0. The temperature dependencies of the rate constants for the reaction of methylamine with MADH were also determined. An iminosemiquinone intermediate for the oxidation of substrate-reduced MADH by amicyanin was detected using stopped-flow spectroscopy, and the presence of the substrate derived nitrogen was confirmed by electron spin echo envelope modulation (ESEEM) spectroscopy. Marcus theory, which was used to analyze the electron transfer reaction between the dithionite-generated redox forms of MADH and amicyanin, gave values of 218 kJ rm mol^{ -1} (2.3 eV) for the reorganizational energy (lambda ) and 11.6 rm cm^{-1} for the coupling rm (H_{AB}). In contrast, the oxidation of substrate-reduced MADH by amicyanin was a gated electron transfer reaction with values for DeltaH* of 76 kJ rm mol^ {-1} and DeltaS* of -41 J rm mol^{ -1} ^circ K^ {-1}. These studies are consistent with the formation of transient unstable intermediates preceeding electron transfer between MADH and amicyanin. Preliminary investigations of the ternary complex of MADH, amicyanin, and cytochrome c_{55li } suggest two distinct cytochrome c _{55li} binding sites on amicyanin. This conclusion is supported by the biphasic nature of the stopped -flow trace, the inhibition of the rm k^ {fast}_{obs} by MADH, and the ionic strength dependence of the two phases. The slow phase had a rate of 3.1 rm s^ {-1} which is consistent with electron transfer between amicyanin and cytochrome c_ {55li} within the ternary complex. The fast phase does not exhibit saturation behavior, must have an electron transfer rate greater than 1000 rm s^{-1}, and likely involves a complex of amicyanin and cytochrome c_{55li } near the hydrophobic patch of amicyanin.

Caffeine Ingestion Reverses the Circadian Rhythm Effects on Neuromuscular Performance in Highly Resistance-Trained Men

PubMed Central

Mora-Rodríguez, Ricardo; Pallarés, Jesús García; López-Samanes, Álvaro; Ortega, Juan Fernando; Fernández-Elías, Valentín E.

2012-01-01

Purpose To investigate whether caffeine ingestion counteracts the morning reduction in neuromuscular performance associated with the circadian rhythm pattern. Methods Twelve highly resistance-trained men underwent a battery of neuromuscular tests under three different conditions; i) morning (10:00 a.m.) with caffeine ingestion (i.e., 3 mg kg−1; AMCAFF trial); ii) morning (10:00 a.m.) with placebo ingestion (AMPLAC trial); and iii) afternoon (18:00 p.m.) with placebo ingestion (PMPLAC trial). A randomized, double-blind, crossover, placebo controlled experimental design was used, with all subjects serving as their own controls. The neuromuscular test battery consisted in the measurement of bar displacement velocity during free-weight full-squat (SQ) and bench press (BP) exercises against loads that elicit maximum strength (75% 1RM load) and muscle power adaptations (1 m s−1 load). Isometric maximum voluntary contraction (MVCLEG) and isometric electrically evoked strength of the right knee (EVOKLEG) were measured to identify caffeine's action mechanisms. Steroid hormone levels (serum testosterone, cortisol and growth hormone) were evaluated at the beginning of each trial (PRE). In addition, plasma norepinephrine (NE) and epinephrine were measured PRE and at the end of each trial following a standardized intense (85% 1RM) 6 repetitions bout of SQ (POST). Results In the PMPLAC trial, dynamic muscle strength and power output were significantly enhanced compared with AMPLAC treatment (3.0%–7.5%; p≤0.05). During AMCAFF trial, muscle strength and power output increased above AMPLAC levels (4.6%–5.7%; p≤0.05) except for BP velocity with 1 m s−1 load (p = 0.06). During AMCAFF, EVOKLEG and NE (a surrogate of maximal muscle sympathetic nerve activation) were increased above AMPLAC trial (14.6% and 96.8% respectively; p≤0.05). Conclusions These results indicate that caffeine ingestion reverses the morning neuromuscular declines in highly resistance-trained men, raising performance to the levels of the afternoon trial. Our electrical stimulation data, along with the NE values, suggest that caffeine increases neuromuscular performance having a direct effect in the muscle. PMID:22496767

The load-velocity profile differs more between men and women than between individuals with different strength levels.

PubMed

Torrejón, Alejandro; Balsalobre-Fernández, Carlos; Haff, G Gregory; García-Ramos, Amador

2018-03-21

This study aimed to determine the suitability of the load-velocity relationship to prescribe the relative load (%1RM) in women, as well as to compare the load-velocity profile between sexes and participants with different strength levels. The load-velocity relationship of 14 men (1RM: 1.17 ± 0.19) and 14 women (1RM: 0.66 ± 0.13) were evaluated in the bench press exercise. The main findings revealed that: (I) the load-velocity relationship was always strong and linear (R 2 range: 0.987-0.993), (II) a steeper load-velocity profile was observed in men compared to women (Effect size [ES]: 1.09), with men showing higher velocities for light loads (ES: - 0.81 and - 0.40 for the y-intercept and 30%1RM, respectively), but women reporting higher velocities for the heavy loads (ES: 1.14 and 1.50 at 90%1RM and 100%1RM, respectively); and (III) while the slope of the load-velocity profile was moderately steeper for weak men compared to their strong counterpart (ES: 1.02), small differences were observed between strong and weak women (ES: - 0.39). While these results support the use of the individual load-velocity relationship to prescribe the %1RM in the bench press exercise for women, they also highlight the large disparities in their load-velocity profile compared to men.

To Compare the Effect of Vibration Therapy and Massage in Prevention of Delayed Onset Muscle Soreness (DOMS).

PubMed

Imtiyaz, Shagufta; Veqar, Zubia; Shareef, M Y

2014-01-01

To compare the effects of vibration therapy and massage in prevention of DOMS. Pre-test and Post-test Control-Group Design was used, 45 healthy female non athletic Subjects were recruited and randomly distributed to the three groups (15 subject in each group). After the subject's initial status was measured experimental groups received vibration therapy (50 Hz vibration for five minutes) or massage therapy (15 minutes) intervention and control group received no treatment, just prior to the eccentric exercise. Subjects were undergoing the following measurements to evaluate the changes in the muscle condition: muscle soreness (pain perception), Range of Motion (ROM), Maximum Isometric Force (MIF), Repetition maximum (RM), Lactate dehydrogenase (LDH) and Cretain Kinase (CK) level. All the parameters except LDH, CK and 1RM were measured before, immediately post intervention, immediately post exercise, 24 hours post exercise, 48 hours post exercise and 72 hours post exercise. LDH, CK and 1 RM were measured before and 48 hours post exercise. Muscle soreness was reported to be significantly less for experimental (vibration and massage) group (p=0.000) as compared to control group at 24, 48, and 72 hours of post-exercise. Experimental and control group did not show any significant difference in MIF immediate (p=0.2898), 24 hours (p=0.4173), 48 hours (p=0.752) and 72 hours (p=0.5297) of post-exercise. Range of motion demonstrated significant recovery in experimental groups in 48 hours (p=0.0016) and 72 hours (p=0.0463). Massage therapy showed significant recovery in 1RM (p=0.000) compared to control group and vibration therapy shows significantly less LDH level (p=0.000) 48 hours of post exercise compare to control group. CK at 48 hours of post exercise in vibration group (p=0.000) and massage group showed (p=0.002) significant difference as compared to control group. Vibration therapy and massage are equally effective in prevention of DOMS. Massage is effective in restoration of concentric strength (1 RM). Yet vibration therapy shows clinically early reduction of pain and is effective in decreasing the level of LDH in 48 hours post exercise periods.

Acute Effect of Countermovement Jumping on Throwing Performance in Track and Field Athletes During Competition.

PubMed

Karampatsos, Giorgos P; Korfiatis, Panagiotis G; Zaras, Nikolaos D; Georgiadis, Giorgos V; Terzis, Gerasimos D

2017-02-01

Karampatsos, GP, Korfiatis, PG, Zaras, ND, Georgiadis, GV, and Terzis, GD. Acute effect of countermovement jumping on throwing performance in track and field athletes during competition. J Strength Cond Res 32(1): 359-364, 2017-The purpose of the study was to investigate whether performing 3 consecutive countermovement jumps (CMJs) just before an attempt enhances performance in track and field throwers during competition. Twelve shot putters, 8 hammer throwers, 9 discus throwers, and 3 javelin throwers of both sexes participated in the study. They performed 3 maximal CMJs 85 ± 12 seconds before the second, fourth, and sixth attempt during 3 different official competitions of national level. Maximal strength (1 repetition maximum [1RM]) in squat and bench press was measured 1 week after the competition. Mean throwing performance was significantly higher after the CMJs intervention (2.66 ± 4.3%, range of increase 0.02-18.98%, p = 0.0001). Similarly, maximum throwing performance was significantly higher after the CMJs (2.76 ± 3.29%, range of increase 0.09-13.93%, p = 0.0009). All but 2 athletes increased their best performance after the CMJs. The percentage increase in performance was similar between sexes (male athletes 2.56 ± 3.01%; female athletes 3.06 ± 3.76%, p = 0.677), but it was higher for the "lighter throws" (discus and javelin throw: 4.66 ± 4.11%) compared with the "heavier throws" (shot and hammer throw: 1.62 ± 2.04%, p = 0.008). The percentage increase in performance was not significantly correlated with 1RM squat or bench press, anthropometric characteristics, and personal best performance. These results suggest that performing 3 CMJs approximately 1 minute before an attempt may increase track and field throwing performance during competition.

Effects of Resistance Training and Combined Training Program on Repeated Sprint Ability in Futsal Players.

PubMed

Torres-Torrelo, Julio; Rodríguez-Rosell, David; Mora-Custodio, Ricardo; Pareja-Blanco, Fernando; Yañez-García, Juan Manuel; González-Badillo, Juan José

2018-05-16

The purpose of this study was to compare the effects of 6 weeks resistance training (RT) with combined RT and loaded change of direction (CD) exercise on muscle strength and repeated sprint ability (RSA) in futsal players. Thirty-four players (age: 23.7±4.1 years; height: 1.77±0.06 m; body mass: 74.1±8.2 kg) were randomly assigned into three groups: full squat group (SG, n=12), combined full squat and CD group (S+CDG, n=12), and control group (CG, n=10). The RT for SG consisted of full squat with low-load (~45-60% 1RM) and low-volume (2-3 sets and 4-6 repetitions), whereas the S+CDG performed the same RT program combined with loaded CD (2-5 sets of 10 s). Estimated one-repetition maximum (1RM est ) and variables derived from RSA test including mean sprint time (RSA mean ), best sprint time (RSA best ), percent sprint decrement (S dec ), mean ground contact time (GCT mean ) and mean step length (SL) were selected as testing variables. Changes in sprint time and GCT in each sprint were also analysed. Both experimental groups showed significant (P<0.05-0.001) improvements for 1RM est , RSA best and first and second sprint time. In addition, S+CDG achieved significant (P<0.05-0.001) improvements in RSA mean, sprint time (from fifth to ninth sprint) and GCT (from third to eighth sprint). These results indicate that only 6 weeks of low-load and low-volume RT combined with CD in addition to routine futsal training is enough to improve RSA and strength performance simultaneously in futsal players. © Georg Thieme Verlag KG Stuttgart · New York.

Acute effects of various weighted bat warm-up protocols on bat velocity.

PubMed

Reyes, G Francis; Dolny, Dennis

2009-10-01

Although research has provided evidence of increased muscular performance following a facilitation set of resistance exercise, this has not been established for use prior to measuring baseball bat velocity. The purpose of this study was to determine the effectiveness of selected weighted bat warm-up protocols to enhance bat velocity in collegiate baseball players. Nineteen collegiate baseball players (age = 20.15 +/- 1.46 years) were tested for upper-body strength by a 3-repetition maximum (RM) bench press (mean = 97.98 +/- 14.54 kg) and mean bat velocity. Nine weighted bat warm-up protocols, utilizing 3 weighted bats (light = 794 g; standard = 850 g; heavy = 1,531 g) were swung in 3 sets of 6 repetitions in different orders. A control trial involved the warm-up protocol utilizing only the standard bat. Pearson product correlation revealed a significant relationship between 3RM strength and pretest bat velocity (r = 0.51, p = 0.01). Repeated measures analysis of variance (ANOVA) revealed no significant treatment effects of warm-up protocol on bat velocity. However, the order of standard, light, heavy bat sequence resulted in the greatest increase in bat velocity (+6.03%). These results suggest that upper-body muscle strength influences bat velocity. It appears that the standard, light, heavy warm-up order may provide the greatest benefit to increase subsequent bat velocity and may warrant use in game situations.

Effects of Variable Resistance Using Chains on Bench Throw Performance in Trained Rugby Players.

PubMed

Godwin, Mark S; Fernandes, John F T; Twist, Craig

2018-04-01

Godwin, MS, Fernandes, JFT, and Twist, C. Effects of variable resistance using chains on bench throw performance in trained rugby players. J Strength Cond Res 32(4): 950-954, 2018-This study sought to determine the effects of variable resistance using chain resistance on bench throw performance. Eight male rugby union players (19.4 ± 2.3 years, 88.8 ± 6.0 kg, 1RM 105.6 ± 17.0 kg) were recruited from a national league team. In a randomized crossover design, participant's performed 3 bench throws at 45% one repetition maximum (1RM) at a constant load (no chains) or a variable load (30% 1RM constant load and 15% 1RM variable load; chains) with 7 days between conditions. For each repetition, the peak and mean velocity, peak power, peak acceleration, and time to peak velocity were recorded. Differences in peak and mean power were very likely trivial and unclear between the chain and no chain conditions, respectively. Possibly greater peak and likely greater mean bar velocity were accompanied by likely to most likely greater bar velocity between 50 and 400 ms from initiation of bench press in the chain condition compared with the no chain condition. Accordingly, bar acceleration was very likely greater in the chain condition compared with the no chain condition. In conclusion, these results show that the inclusion of chain resistance can acutely enhance several variables in the bench press throw and gives support to this type of training.

Effects of nine weeks of beta-hydroxy-beta- methylbutyrate supplementation on strength and body composition in resistance trained men.

PubMed

Thomson, Jasmine S; Watson, Patricia E; Rowlands, David S

2009-05-01

The dietary supplement beta-hydroxy-beta-methylbutyrate (HMB) is claimed to increase strength, lean body mass, and decrease fat mass when used in conjunction with resistance training. Although there is some support for these claims, the evidence is not conclusive, and it is even less so for resistance trained individuals. Therefore, we aimed to further elucidate the effects of HMB supplementation in trained men. A randomized, double-blind, controlled study design was used to investigate the effects of supplementing 22 resistance trained men with 3 g.d of HMB or corn starch placebo for 9 weeks with resistance training. The effect of HMB on strength was determined using the 1-repetition maximum (1RM) method for the lower body (leg extension) and upper body (bench press, bicep preacher curl) at baseline and after the supplementation period. Body composition was assessed by skinfolds and bioelectrical impedance analysis (BIA). Overall, 9 weeks' HMB supplementation resulted in a clear-cut, trivial increase in combined averaged strength measures of 1.6% (90% confidence limits: +/-4.3%). When considered in isolation, however, leg extension 1RM increased by a substantial 9.1% (90% confidence limits: +/-7.5%), but the effect on upper-body strength was inconclusive (bench press: -1.9 +/- 9.3%; bicep curl: -1.7 +/- 4.7%). Based on BIA estimates, HMB had a decreasing (although inconclusive) influence on fat mass of -9 +/- 14%, but it had a clear, trivial effect on fat-free mass of 0.2 +/- 2.2%. The magnitude of change in body mass was trivial, but the probability of substantial reductions in skinfold thicknesses ranged from negligible to likely. In previously trained men, supplementation of HMB in conjunction with resistance training provides a substantial benefit to lower-body strength, but it has negligible effects on body composition.

No Effect of a Whey Growth Factor Extract during Resistance Training on Strength, Body Composition, or Hypertrophic Gene Expression in Resistance-Trained Young Men.

PubMed

Dale, Michael J; Coates, Alison M; Howe, Peter R C; Tomkinson, Grant R; Haren, Matthew T; Brown, Andrew; Caldow, Marissa; Cameron-Smith, David; Buckley, Jonathan D

2017-06-01

Growth factors can be isolated from bovine milk to form a whey growth factor extract (WGFE). This study examined whether WGFE promoted activation of the AKT/mTOR pathway enabling increased lean tissue mass and strength in resistance trained men. Forty six men with >6 months of resistance training (RT) experience performed 12 weeks of RT. Participants consumed 20 g/day of whey protein and were randomised to receive either 1.6 g WGFE/day (WGFE; n = 22) or 1.6 g cellulose/day (control, CONT; n = 24). The primary outcome was leg press one-repetition maximum (LP1-RM) which was assessed at baseline, 6 and 12 weeks. At baseline and 12 weeks body composition was assessed by dual energy x-ray absorptiometry, and muscle protein synthesis and gene expression were assessed (vastus lateralis biopsy) in a sub-sample (WGFE n = 10, CONT n = 10) pre- and 3 hr post-training. RT increased LP1-RM (+34.9%) and lean tissue mass (+2.3%; p < 0.05) with no difference between treatments (p > 0.48, treatment x time). Post-exercise P70 s6k phosphorylation increased acutely, FOXO3a phosphorylation was unaltered. There were no differences in kinase signalling or gene expression between treatments. Compared with CONT, WGFE did not result in greater increases in lean tissue mass or strength in experienced resistance trained men.

Ectomycorrhizal sporophore distributions in a southeastern Appalachian mixed hardwood/conifer forest with thickets of Rhododendron maximum

Treesearch

John F. Walker; Orson R. Jr. Miller

2002-01-01

Sporophore abundance of putatively ectomycorrhizal fungi was compared in a mature mixed hardwood/conifer forest inside of (1) versus outside of (2) Rhododendron maximum thickets (RmT). Experimental blocks (1/4 ha) were established inside of (3) and outside of (3) RmT at the Coweeta Hydrologic Laboratory in Macon County, North Carolina, USA. Litter...

Effect of Sequencing Strength and Endurance Training in Young Male Soccer Players.

PubMed

Makhlouf, Issam; Castagna, Carlo; Manzi, Vincenzo; Laurencelle, Louis; Behm, David G; Chaouachi, Anis

2016-03-01

This study examined the effects of strength and endurance training sequence (strength before or after endurance) on relevant fitness variables in youth soccer players. Fifty-seven young elite-level male field soccer players (13.7 ± 0.5 years; 164 ± 8.3 cm; 53.5 ± 8.6 kg; body fat; 15.6 ± 3.9%) were randomly assigned to a control (n = 14, CG) and 3 experimental training groups (twice a week for 12 weeks) strength before (SE, n = 15), after (ES, n = 14) or on alternate days (ASE, n = 14) with endurance training. A significant (p = 0.001) intervention main effect was detected. There were only trivial training sequence differences (ES vs. SE) for all variables (p > 0.05). The CG showed large squat 1 repetition maximum (1RM) and medium sprint, change of direction ability, and jump improvements. ASE demonstrated a trivial difference in endurance performance with ES and SE (p > 0.05). Large to medium greater improvements for SE and ES were reported compared with ASE for sprinting over 10 and 30 m (p < 0.02). The SE squat 1RM was higher than in ASE (moderate, p < 0.02). Postintervention differences between ES and SE with CG fitness variables were small to medium (p ≤ 0.05) except for a large SE advantage with the Yo-Yo intermittent recovery test (p < 0.001, large). This study showed no effect of intrasession training sequence on soccer fitness-relevant variables. However, combining strength and endurance within a single training session provided superior results vs. training on alternate days. Concurrent training may be considered as an effective and safe training method for the development of the prospective soccer player.

ACTN3 genotype is associated with increases in muscle strength in response to resistance training in women.

PubMed

Clarkson, Priscilla M; Devaney, Joseph M; Gordish-Dressman, Heather; Thompson, Paul D; Hubal, Monica J; Urso, Maria; Price, Thomas B; Angelopoulos, Theodore J; Gordon, Paul M; Moyna, Niall M; Pescatello, Linda S; Visich, Paul S; Zoeller, Robert F; Seip, Richard L; Hoffman, Eric P

2005-07-01

The alpha-actinin 3 (ACTN3) gene encodes a protein of the Z disk of myofibers, and a polymorphism of ACTN3 results in complete loss of the protein. The ACTN3 genotype (R577X) has been found to be associated with performance in Australian elite athletes (Yang N, MacArthur DG, Gulbin JP, Hahn AG, Beggs AH, Easteal S, and North K. Am J Hum Genet 73: 627-631, 2003). We studied associations between ACTN3 genotype and muscle size [cross-sectional area of the biceps brachii via magnetic resonance imaging (MRI)] and elbow flexor isometric (MVC) and dynamic [1-repetition maximum (1-RM)] strength in a large group of men (N = 247) and women (N = 355) enrolled in a 12-wk standardized elbow flexor/extensor resistance training program of the nondominant arm at one of eight study centers. We found no association between ACTN3 R577X genotype and muscle phenotype in men. However, women homozygous for the ACTN3 577X allele (XX) had lower baseline MVC compared with heterozygotes (P < 0.05) when adjusted for body mass and age. Women homozygous for the mutant allele (577X) demonstrated greater absolute and relative 1-RM gains compared with the homozygous wild type (RR) after resistance training when adjusted for body mass and age (P < 0.05). There was a trend for a dose-response with genotype such that gains were greatest for XX and least for RR. Significant associations were validated in at least one ethnic subpopulation (Caucasians, Asians) and were independent of training volume. About 2% of baseline MVC and of 1-RM strength gain after training were attributable to ACTN3 genotype (likelihood-ratio test P value, P = 0.01), suggesting that ACTN3 is one of many genes contributing to genetic variation in muscle performance and adaptation to exercise.

Anthropometric and Physiological Characteristics of Brazilian Jiu-Jitsu Athletes.

PubMed

Øvretveit, Karsten

2018-04-01

Øvretveit, K. Anthropometric and physiological characteristics of Brazilian jiu-jitsu athletes. J Strength Cond Res 32(4): 997-1004, 2018-The aim of this study was to describe anthropometric and physiological characteristics of Brazilian jiu-jitsu (BJJ) athletes. For this purpose, 42 male athletes were recruited from one of the largest BJJ academies in central Norway. The subjects were 32 ± 6 (SD) years old, 181.9 ± 7.2 cm tall, had a body mass (mb) of 85.7 ± 10.6 kg, and 5.5 ± 3.7 years of BJJ training experience. The subjects underwent segmental multifrequency bioelectrical impedance analysis of body composition (BIA), direct measurements of pulmonary function and maximal oxygen uptake (V[Combining Dot Above]O2max), assessments of 1-repetition maximum (1RM) in the parallel squat and paused bench press, and one set of pronated-grip pull-ups to muscular failure. The average body fat percentage (BF) was 12.9 ± 5.3%. The subjects achieved a V[Combining Dot Above]O2max of 50.6 ± 4.6 mL·kg·min. Absolute squat 1RM (113.2 ± 20.4 kg) was significantly higher than bench press 1RM (87.6 ± 16.5 kg) (p < 0.001). The mean number of pull-ups achieved was 9 ± 4. These characteristics were generally independent of rank, training experience, weekly training volume, competition volume, and style preference. Additional strength training was associated with improved bench press performance (p < 0.05). Beyond that, additional strength and/or conditioning training had no apparent relationship with any variable (p > 0.05). This study provides novel insight into the fitness levels of BJJ athletes. These findings indicate the degree of exercise response to BJJ training and are applicable in athlete assessment and exercise prescription in this population.

Effects of endurance training only versus same-session combined endurance and strength training on physical performance and serum hormone concentrations in recreational endurance runners.

PubMed

Schumann, Moritz; Mykkänen, Olli-Pekka; Doma, Kenji; Mazzolari, Raffaele; Nyman, Kai; Häkkinen, Keijo

2015-01-01

This study investigated the effects of endurance training only (E, n = 14) and same-session combined training, when strength training is repeatedly preceded by endurance loading (endurance and strength training (E+S), n = 13) on endurance (1000-m running time during incremental field test) and strength performance (1-repetition maximum (1RM) in dynamic leg press), basal serum hormone concentrations, and endurance loading-induced force and hormone responses in recreationally endurance-trained men. E was identical in the 2 groups and consisted of steady-state and interval running, 4-6 times per week for 24 weeks. E+S performed additional mixed-maximal and explosive-strength training (2 times per week) immediately following an incremental running session (35-45 min, 65%-85% maximal heart rate). E and E+S decreased running time at week 12 (-8% ± 5%, p = 0.001 and -7% ± 3%, p < 0.001) and 24 (-13% ± 5%, p < 0.001 and -9% ± 5%, p = 0.001). Strength performance decreased in E at week 24 (-5% ± 5%, p = 0.014) but was maintained in E+S (between-groups at week 12 and 24, p = 0.014 and 0.011, respectively). Basal serum testosterone and cortisol concentrations remained unaltered in E and E+S but testosterone/sex hormone binding globulin ratio decreased in E+S at week 12 (-19% ± 26%, p = 0.006). At week 0 and 24, endurance loading-induced acute force (-5% to -9%, p = 0.032 to 0.001) and testosterone and cortisol responses (18%-47%, p = 0.013 to p < 0.001) were similar between E and E+S. This study showed no endurance performance benefits when strength training was performed repeatedly after endurance training compared with endurance training only. This was supported by similar acute responses in force and hormonal measures immediately post-endurance loading after the training with sustained 1RM strength in E+S.

Mean Velocity vs. Mean Propulsive Velocity vs. Peak Velocity: Which Variable Determines Bench Press Relative Load With Higher Reliability?

PubMed

García-Ramos, Amador; Pestaña-Melero, Francisco L; Pérez-Castilla, Alejandro; Rojas, Francisco J; Gregory Haff, G

2018-05-01

García-Ramos, A, Pestaña-Melero, FL, Pérez-Castilla, A, Rojas, FJ, and Haff, GG. Mean velocity vs. mean propulsive velocity vs. peak velocity: which variable determines bench press relative load with higher reliability? J Strength Cond Res 32(5): 1273-1279, 2018-This study aimed to compare between 3 velocity variables (mean velocity [MV], mean propulsive velocity [MPV], and peak velocity [PV]): (a) the linearity of the load-velocity relationship, (b) the accuracy of general regression equations to predict relative load (%1RM), and (c) the between-session reliability of the velocity attained at each percentage of the 1-repetition maximum (%1RM). The full load-velocity relationship of 30 men was evaluated by means of linear regression models in the concentric-only and eccentric-concentric bench press throw (BPT) variants performed with a Smith machine. The 2 sessions of each BPT variant were performed within the same week separated by 48-72 hours. The main findings were as follows: (a) the MV showed the strongest linearity of the load-velocity relationship (median r = 0.989 for concentric-only BPT and 0.993 for eccentric-concentric BPT), followed by MPV (median r = 0.983 for concentric-only BPT and 0.980 for eccentric-concentric BPT), and finally PV (median r = 0.974 for concentric-only BPT and 0.969 for eccentric-concentric BPT); (b) the accuracy of the general regression equations to predict relative load (%1RM) from movement velocity was higher for MV (SEE = 3.80-4.76%1RM) than for MPV (SEE = 4.91-5.56%1RM) and PV (SEE = 5.36-5.77%1RM); and (c) the PV showed the lowest within-subjects coefficient of variation (3.50%-3.87%), followed by MV (4.05%-4.93%), and finally MPV (5.11%-6.03%). Taken together, these results suggest that the MV could be the most appropriate variable for monitoring the relative load (%1RM) in the BPT exercise performed in a Smith machine.

Effect of an Unstable Load on Primary and Stabilizing Muscles During the Bench Press.

PubMed

Ostrowski, Stephanie J; Carlson, Lara A; Lawrence, Michael A

2017-02-01

Ostrowski, SJ, Carlson, LA, and Lawrence, MA. Effect of an unstable load on primary and stabilizing muscles during the bench press. J Strength Cond Res 31(2): 430-434, 2017-Unstable resistance exercises are performed to increase activity of stabilizing muscles. The premise is that this increase in activity will yield greater strength gains than traditional resistance exercises. The purpose of this study was to determine if an unstable load increases muscle activity of stabilizing muscles during a bench press as compared with a standard bench press with a typical load. Fifteen resistance-trained males (age 24.2 ± 2.7 years, mass 84.8 ± 12.0 kg, height 1.77 ± 0.05 m, weight lifting experience 9.9 ± 3.4 years, and bench press 1 repetition maximum [1RM] 107.5 ± 25.9 kg) volunteered for this study. Subjects pressed 2 sets of 5 repetitions in both stable (75% 1RM) and unstable (60% 1RM) conditions using a standard barbell and a flexible Earthquake bar, respectively. Surface electromyography was used to detect muscle activity of primary movers (pectoralis major, anterior deltoid, and triceps) and stabilizing musculature (latissimus dorsi, middle and posterior deltoid, biceps brachii, and upper trapezius). Muscle activity was compared using a multivariate analysis of variance to determine significant (p ≤ 0.05) phase and condition differences. The right and left biceps and the left middle deltoid were significantly more active in the unstable condition. Some of the stabilizing muscles were found to be significantly more active in the unstable condition with 15% less weight. Therefore, bench pressing with an unstable load appears promising in activating stabilizing musculature compared with pressing a typical barbell.

Comparison of acute countermovement jump responses after functional isometric and dynamic half squats.

PubMed

Boyd, David A; Donald, Neil; Balshaw, Thomas G

2014-12-01

The purpose of this study was to compare acute countermovement jump (CMJ) responses after functional isometric (FI) and dynamic half (DH) squats. Ten strength-trained males (relative full back squat 1 repetition maximum [1RM]: 1.9 ± 0.2) participated in a randomized crossover design study. On 2 separate days, participants performed baseline CMJs followed by either FI or DH squats loaded with 150% of full back squat 1RM. Further CMJs were performed between 2 and 11 minutes after FI or DH squats. Kinematic and kinetic CMJ variables were measured. There were no differences observed between conditions when peak CMJ variables after FI or DH squats were compared with baseline values (p > 0.05). Countermovement jump time effects (p ≤ 0.05) were observed after squats. Increases in peak force (p ≤ 0.05; FI: 3.9%, range: -0.9 to 9.1%; DH: 4.2%, range: 0.0-11.5%) and decreases in peak power (p ≤ 0.05; FI: -0.4%, range: -5.1 to 4.0%; DH: -1.1%, range: -6.6 to 2.9%) occurred for combined condition data. Positive correlations between lower-body strength and the extent or timing of acute CMJ responses were not detected (p > 0.05). Because of the apparent lack of additive acute CMJ responses, the use of conventional DH squat protocols should be considered rather than FI squats in precompetition and training situations. Furthermore, the establishment of individual FI and DH squat protocols also seems to be necessary, rather than relying on relative lower-body strength to predict the nature of acute CMJ responses.

Lower limb strength training in children with cerebral palsy – a randomized controlled trial protocol for functional strength training based on progressive resistance exercise principles

PubMed Central

Scholtes, Vanessa A; Dallmeijer, Annet J; Rameckers, Eugene A; Verschuren, Olaf; Tempelaars, Els; Hensen, Maartje; Becher, Jules G

2008-01-01

Background Until recently, strength training in children with cerebral palsy (CP) was considered to be inappropriate, because it could lead to increased spasticity or abnormal movement patterns. However, the results of recent studies suggest that progressive strength training can lead to increased strength and improved function, but low methodological quality and incomplete reporting on the training protocols hampers adequate interpretation of the results. This paper describes the design and training protocol of a randomized controlled trial to assess the effects of a school-based progressive functional strength training program for children with CP. Methods/Results Fifty-one children with Gross Motor Function Classification Systems levels I to III, aged of 6 to 13 years, were recruited. Using stratified randomization, each child was assigned to an intervention group (strength training) or a control group (usual care). The strength training was given in groups of 4–5 children, 3 times a week, for a period of 12 weeks. Each training session focussed on four exercises out of a 5-exercise circuit. The training load was gradually increased based on the child's maximum level of strength, as determined by the 8 Repetition Maximum (8 RM). To evaluate the effectiveness of the training, all children were evaluated before, during, directly after, and 6 weeks after the intervention period. Primary outcomes in this study were gross motor function (measured with the Gross Motor Function Measure and functional muscle strength tests) and walking ability (measured with the 10-meter, the 1-minute and the timed stair test). Secondary outcomes were lower limb muscle strength (measured with a 6 RM test, isometric strength tests, and a sprint capacity test), mobility (measured with a mobility questionnaire), and sport activities (measured with the Children's Assessment of Participation and Enjoyment). Spasticity and range of motion were assessed to evaluate any adverse events. Conclusion Randomized clinical trials are considered to present the highest level of evidence. Nevertheless, it is of utmost importance to report on the design, the applied evaluation methods, and all elements of the intervention, to ensure adequate interpretation of the results and to facilitate implementation of the intervention in clinical practice if the results are positive. Trial Registration Trial Register NTR1403 PMID:18842125

Hang cleans and hang snatches produce similar improvements in female collegiate athletes

PubMed Central

Ayers, JL; DeBeliso, M; Sevene, TG

2016-01-01

Olympic weightlifting movements and their variations are believed to be among the most effective ways to improve power, strength, and speed in athletes. This study investigated the effects of two Olympic weightlifting variations (hang cleans and hang snatches), on power (vertical jump height), strength (1RM back squat), and speed (40-yard sprint) in female collegiate athletes. 23 NCAA Division I female athletes were randomly assigned to either a hang clean group or hang snatch group. Athletes participated in two workout sessions a week for six weeks, performing either hang cleans or hang snatches for five sets of three repetitions with a load of 80-85% 1RM, concurrent with their existing, season-specific, resistance training program. Vertical jump height, 1RM back squat, and 40-yard sprint all had a significant, positive improvement from pre-training to post-training in both groups (p≤0.01). However, when comparing the gain scores between groups, there was no significant difference between the hang clean and hang snatch groups for any of the three dependent variables (i.e., vertical jump height, p=0.46; 1RM back squat, p=0.20; and 40-yard sprint, p=0.46). Short-term training emphasizing hang cleans or hang snatches produced similar improvements in power, strength, and speed in female collegiate athletes. This provides strength and conditioning professionals with two viable programmatic options in athletic-based exercises to improve power, strength, and speed. PMID:27601779

Hang cleans and hang snatches produce similar improvements in female collegiate athletes.

PubMed

Ayers, J L; DeBeliso, M; Sevene, T G; Adams, K J

2016-09-01

Olympic weightlifting movements and their variations are believed to be among the most effective ways to improve power, strength, and speed in athletes. This study investigated the effects of two Olympic weightlifting variations (hang cleans and hang snatches), on power (vertical jump height), strength (1RM back squat), and speed (40-yard sprint) in female collegiate athletes. 23 NCAA Division I female athletes were randomly assigned to either a hang clean group or hang snatch group. Athletes participated in two workout sessions a week for six weeks, performing either hang cleans or hang snatches for five sets of three repetitions with a load of 80-85% 1RM, concurrent with their existing, season-specific, resistance training program. Vertical jump height, 1RM back squat, and 40-yard sprint all had a significant, positive improvement from pre-training to post-training in both groups (p≤0.01). However, when comparing the gain scores between groups, there was no significant difference between the hang clean and hang snatch groups for any of the three dependent variables (i.e., vertical jump height, p=0.46; 1RM back squat, p=0.20; and 40-yard sprint, p=0.46). Short-term training emphasizing hang cleans or hang snatches produced similar improvements in power, strength, and speed in female collegiate athletes. This provides strength and conditioning professionals with two viable programmatic options in athletic-based exercises to improve power, strength, and speed.

Effects of Low- vs. High-Load Resistance Training on Muscle Strength and Hypertrophy in Well-Trained Men.

PubMed

Schoenfeld, Brad J; Peterson, Mark D; Ogborn, Dan; Contreras, Bret; Sonmez, Gul T

2015-10-01

The purpose of this study was to compare the effect of low- versus high-load resistance training (RT) on muscular adaptations in well-trained subjects. Eighteen young men experienced in RT were matched according to baseline strength and then randomly assigned to 1 of 2 experimental groups: a low-load RT routine (LL) where 25-35 repetitions were performed per set per exercise (n = 9) or a high-load RT routine (HL) where 8-12 repetitions were performed per set per exercise (n = 9). During each session, subjects in both groups performed 3 sets of 7 different exercises representing all major muscles. Training was performed 3 times per week on nonconsecutive days, for a total of 8 weeks. Both HL and LL conditions produced significant increases in thickness of the elbow flexors (5.3 vs. 8.6%, respectively), elbow extensors (6.0 vs. 5.2%, respectively), and quadriceps femoris (9.3 vs. 9.5%, respectively), with no significant differences noted between groups. Improvements in back squat strength were significantly greater for HL compared with LL (19.6 vs. 8.8%, respectively), and there was a trend for greater increases in 1 repetition maximum (1RM) bench press (6.5 vs. 2.0%, respectively). Upper body muscle endurance (assessed by the bench press at 50% 1RM to failure) improved to a greater extent in LL compared with HL (16.6 vs. -1.2%, respectively). These findings indicate that both HL and LL training to failure can elicit significant increases in muscle hypertrophy among well-trained young men; however, HL training is superior for maximizing strength adaptations.

Estimations of One Repetition Maximum and Isometric Peak Torque in Knee Extension Based on the Relationship Between Force and Velocity.

PubMed

Sugiura, Yoshito; Hatanaka, Yasuhiko; Arai, Tomoaki; Sakurai, Hiroaki; Kanada, Yoshikiyo

2016-04-01

We aimed to investigate whether a linear regression formula based on the relationship between joint torque and angular velocity measured using a high-speed video camera and image measurement software is effective for estimating 1 repetition maximum (1RM) and isometric peak torque in knee extension. Subjects comprised 20 healthy men (mean ± SD; age, 27.4 ± 4.9 years; height, 170.3 ± 4.4 cm; and body weight, 66.1 ± 10.9 kg). The exercise load ranged from 40% to 150% 1RM. Peak angular velocity (PAV) and peak torque were used to estimate 1RM and isometric peak torque. To elucidate the relationship between force and velocity in knee extension, the relationship between the relative proportion of 1RM (% 1RM) and PAV was examined using simple regression analysis. The concordance rate between the estimated value and actual measurement of 1RM and isometric peak torque was examined using intraclass correlation coefficients (ICCs). Reliability of the regression line of PAV and % 1RM was 0.95. The concordance rate between the actual measurement and estimated value of 1RM resulted in an ICC(2,1) of 0.93 and that of isometric peak torque had an ICC(2,1) of 0.87 and 0.86 for 6 and 3 levels of load, respectively. Our method for estimating 1RM was effective for decreasing the measurement time and reducing patients' burden. Additionally, isometric peak torque can be estimated using 3 levels of load, as we obtained the same results as those reported previously. We plan to expand the range of subjects and examine the generalizability of our results.

Using the Richtmyer-Meshkov flow to infer the strength of LY-12 aluminum at extreme conditions

NASA Astrophysics Data System (ADS)

Yin, Jianwei; Pan, Hao; Peng, Jiangxiang; Wu, Zihui; Yu, Yuying; Hu, Xiaomian

2017-06-01

An improved analytical model of the Richtmyer-Meshkov (RM) flow in the elastoplastic materials is presented in this paper. This model describes the stabilization by yield strength (Y) effect on the RM flow in solids and linear relationships between initial configurations of perturbation and the growth. Then we make use of the model to analysis the explosion driven RM flow experiments with solid LY12 and test our model by comparing the predicted Y of existing strength models. Finally, we perform a plate impact experiment with solid LY12 aluminium alloy to validate our model and infer Y is about 1.23 GPa for a 28 GPa shock and a strain rate of 7.5 ×106 .

Functional and Muscle-Size Effects of Flywheel Resistance Training with Eccentric-Overload in Professional Handball Players

PubMed Central

García-López, David; de Paz, José A

2017-01-01

Abstract The aim of the study was to analyse the effects of 6 week (15 sessions) flywheel resistance training with eccentric-overload (FRTEO) on different functional and anatomical variables in professional handball players. Twenty-nine athletes were recruited and randomly divided into two groups. The experimental group (EXP, n = 15) carried out 15 sessions of FRTEO in the leg-press exercise, with 4 sets of 7 repetitions at a maximum-concentric effort. The control group (CON, n = 14) performed the same number of training sessions including 4 sets of 7 maximum repetitions (7RM) using a weight-stack leg-press machine. The results which were measured included maximal dynamic strength (1RM), muscle power at different submaximal loads (PO), vertical jump height (CMJ and SJ), 20 m sprint time (20 m), T-test time (T-test), and Vastus-Lateralis muscle (VL) thickness. The results of the EXP group showed a substantially better improvement (p < 0.05-0.001) in PO, CMJ, 20 m, T-test and VL, compared to the CON group. Moreover, athletes from the EXP group showed significant improvements concerning all the variables measured: 1RM (ES = 0.72), PO (ES = 0.42 - 0.83), CMJ (ES = 0.61), SJ (ES = 0.54), 20 m (ES = 1.45), T-test (ES = 1.44), and VL (ES = 0.63 - 1.64). Since handball requires repeated short, explosive effort such as accelerations and decelerations during sprints with changes of direction, these results suggest that FRTEO affects functional and anatomical changes in a way which improves performance in well-trained professional handball players. PMID:29339993

Short-Term Effects of Combined High-Intensity Strength and Sprint Interval Training on Anthropometric Characteristics and Physical Performance of Elite Team Handball Players.

PubMed

Hermassi, Souhail; Chelly, Mohamed Souhail; Fieseler, Georg; Bartels, Thomas; Schulze, Stephan; Delank, Karl-Stefan; Shepard, Roy J; Schwesig, René

2017-12-01

Muscular strength and speed are critical physical factors in determining the technical and tactical skills of elite team handball players. This study thus investigated the effect of high-intensity muscular strength and sprint interval training (SIT) on lower limb explosive performance and anthropometric characteristics in 22 male handball athletes aged 20.2 ± 0.1 years. A training group (TG, n = 12) and a control group (CG, n = 10) were followed over 8 weeks parallel to regular handball training. The TG received combined additional high-intensity muscular strength and interval training twice per week during this period. The muscular training was comprised of 3 - 4 sets of 70 - 85 % of 1-RM (repetition maximum) of dynamic back half squat exercise; followed immediately by a short sprint program with 4, 5, and 6 maximal intensity repetitions of 30 m runs. Strength (1-RM of the half back-squat and bench press), first step (V1S), first 5 m (V5 m), squat jumps (SJ), counter movement jumps (CMJ) and the Modified Agility Test (MAT) were tested at the beginning and end of the study. Significant interaction effects (group × time) were observed for all parameters (η² range: 0.531 (MAT) to 0.829 (First 5 m)). All 10 parameters showed relevant intervention effects (d> 0.5) in the TG (highest intervention effect: CMJ: d = 4.05), the mean effect size being d = 1.85. In contrast, scores for the CG either remained unchanged or decreased (d = -0.24). We conclude that combined high-intensity strength and sprint interval training during the competitive season should be recommended to elite male handball players as a means of improving handball-related performance characteristics without compromising other critical aspects of the individual's performance. © Georg Thieme Verlag KG Stuttgart · New York.

The Effects of Supplementary Low-Load Blood Flow Restriction Training on Morphological and Performance-Based Adaptations in Team Sport Athletes.

PubMed

Scott, Brendan R; Peiffer, Jeremiah J; Goods, Paul S R

2017-08-01

Scott, BR, Peiffer, JJ, and Goods, PSR. The effects of supplementary low-load blood flow restriction training on morphological and performance-based adaptations in team sport athletes. J Strength Cond Res 31(8): 2147-2154, 2017-Low-load resistance training with blood flow restriction (BFR) may be a method to enhance muscular development even in trained athletes. This study aimed to assess whether supplemental low-load BFR training can improve muscle size, strength, and physical performance characteristics in team sport athletes. Twenty-one semiprofessional Australian football athletes were assessed for 3-repetition maximum (3RM) and muscular endurance in the back squat, vastus lateralis muscle architecture, and performance in sprint and vertical jump tasks. Participants then undertook a 5-week training program, consisting of normal high-load resistance training supplemented by low-load squats with (LLBFR) or without (LL) BFR. Participants also performed regular conditioning and football training during this period. After the training intervention, participants again completed the pretraining testing battery. Squat 3RM and endurance increased from pretraining levels in both LL (3RM = 12.5% increase; endurance = 24.1% increase; p ≤ 0.007) and LLBFR (3RM = 12.3% increase; endurance = 21.2% increase; p = 0.007) groups, though there were no between-group differences. No post-training changes were observed for muscle architecture, or performance in sprinting and jumping tasks. Although squat 3RM and endurance performance increased in both groups, adding BFR during supplemental exercise did not enhance these responses. Similarly, there were no large differences in the assessments of sprint, acceleration, and jumping performance between the groups after training. These findings suggest that although LLBFR did not negatively affect adaptive responses to resistance training, this training strategy may not provide added benefit for healthy Australian football athletes already undertaking a rigorous training schedule.

Endurance Training Intensity Does Not Mediate Interference to Maximal Lower-Body Strength Gain during Short-Term Concurrent Training

PubMed Central

Fyfe, Jackson J.; Bartlett, Jonathan D.; Hanson, Erik D.; Stepto, Nigel K.; Bishop, David J.

2016-01-01

We determined the effect of concurrent training incorporating either high-intensity interval training (HIT) or moderate-intensity continuous training (MICT) on maximal strength, counter-movement jump (CMJ) performance, and body composition adaptations, compared with single-mode resistance training (RT). Twenty-three recreationally-active males (mean ± SD: age, 29.6 ± 5.5 y; V˙O2peak, 44 ± 11 mL kg−1·min−1) underwent 8 weeks (3 sessions·wk−1) of either: (1) HIT combined with RT (HIT+RT group, n = 8), (2) work-matched MICT combined with RT (MICT+RT group, n = 7), or (3) RT performed alone (RT group, n = 8). Measures of aerobic capacity, maximal (1-RM) strength, CMJ performance and body composition (DXA) were obtained before (PRE), mid-way (MID), and after (POST) training. Maximal (one-repetition maximum [1-RM]) leg press strength was improved from PRE to POST for RT (mean change ± 90% confidence interval; 38.5 ± 8.5%; effect size [ES] ± 90% confidence interval; 1.26 ± 0.24; P < 0.001), HIT+RT (28.7 ± 5.3%; ES, 1.17 ± 0.19; P < 0.001), and MICT+RT (27.5 ± 4.6%, ES, 0.81 ± 0.12; P < 0.001); however, the magnitude of this change was greater for RT vs. both HIT+RT (7.4 ± 8.7%; ES, 0.40 ± 0.40) and MICT+RT (8.2 ± 9.9%; ES, 0.60 ± 0.45). There were no substantial between-group differences in 1-RM bench press strength gain. RT induced greater changes in peak CMJ force vs. HIT+RT (6.8 ± 4.5%; ES, 0.41 ± 0.28) and MICT+RT (9.9 ± 11.2%; ES, 0.54 ± 0.65), and greater improvements in maximal CMJ rate of force development (RFD) vs. HIT+RT (24.1 ± 26.1%; ES, 0.72 ± 0.88). Lower-body lean mass was similarly increased for RT (4.1 ± 2.0%; ES; 0.33 ± 0.16; P = 0.023) and MICT+RT (3.6 ± 2.4%; ES; 0.45 ± 0.30; P = 0.052); however, this change was attenuated for HIT+RT (1.8 ± 1.6%; ES; 0.13 ± 0.12; P = 0.069). We conclude that concurrent training incorporating either HIT or work-matched MICT similarly attenuates improvements in maximal lower-body strength and indices of CMJ performance compared with RT performed alone. This suggests endurance training intensity is not a critical mediator of interference to maximal strength gain during short-term concurrent training. PMID:27857692

Endurance Training Intensity Does Not Mediate Interference to Maximal Lower-Body Strength Gain during Short-Term Concurrent Training.

PubMed

Fyfe, Jackson J; Bartlett, Jonathan D; Hanson, Erik D; Stepto, Nigel K; Bishop, David J

2016-01-01

We determined the effect of concurrent training incorporating either high-intensity interval training (HIT) or moderate-intensity continuous training (MICT) on maximal strength, counter-movement jump (CMJ) performance, and body composition adaptations, compared with single-mode resistance training (RT). Twenty-three recreationally-active males (mean ± SD: age, 29.6 ± 5.5 y; [Formula: see text], 44 ± 11 mL kg -1 ·min -1 ) underwent 8 weeks (3 sessions·wk -1 ) of either: (1) HIT combined with RT (HIT+RT group, n = 8), (2) work-matched MICT combined with RT (MICT+RT group, n = 7), or (3) RT performed alone (RT group, n = 8). Measures of aerobic capacity, maximal (1-RM) strength, CMJ performance and body composition (DXA) were obtained before (PRE), mid-way (MID), and after (POST) training. Maximal (one-repetition maximum [1-RM]) leg press strength was improved from PRE to POST for RT (mean change ± 90% confidence interval; 38.5 ± 8.5%; effect size [ES] ± 90% confidence interval; 1.26 ± 0.24; P < 0.001), HIT+RT (28.7 ± 5.3%; ES, 1.17 ± 0.19; P < 0.001), and MICT+RT (27.5 ± 4.6%, ES, 0.81 ± 0.12; P < 0.001); however, the magnitude of this change was greater for RT vs. both HIT+RT (7.4 ± 8.7%; ES, 0.40 ± 0.40) and MICT+RT (8.2 ± 9.9%; ES, 0.60 ± 0.45). There were no substantial between-group differences in 1-RM bench press strength gain. RT induced greater changes in peak CMJ force vs. HIT+RT (6.8 ± 4.5%; ES, 0.41 ± 0.28) and MICT+RT (9.9 ± 11.2%; ES, 0.54 ± 0.65), and greater improvements in maximal CMJ rate of force development (RFD) vs. HIT+RT (24.1 ± 26.1%; ES, 0.72 ± 0.88). Lower-body lean mass was similarly increased for RT (4.1 ± 2.0%; ES; 0.33 ± 0.16; P = 0.023) and MICT+RT (3.6 ± 2.4%; ES; 0.45 ± 0.30; P = 0.052); however, this change was attenuated for HIT+RT (1.8 ± 1.6%; ES; 0.13 ± 0.12; P = 0.069). We conclude that concurrent training incorporating either HIT or work-matched MICT similarly attenuates improvements in maximal lower-body strength and indices of CMJ performance compared with RT performed alone. This suggests endurance training intensity is not a critical mediator of interference to maximal strength gain during short-term concurrent training.

Trunk muscle activation in the back and hack squat at the same relative loads.

PubMed

Clark, David R; Lambert, Michael I; Hunter, Angus M

2017-07-12

The hack squat (HS) is likely to produce a greater 1 repetition maximum (1RM) compared to the back squat (BS). This can be attributed to the support of the trunk during the HS compared to no support during BS. This support however, may compromise trunk muscle activation (TMA), therefore producing different training adaptations. Accordingly, the purpose of this study was to compare 1RM in BS and HS and TMA at 4 relative loads, 65, 75, 85 and 95% of maximal system mass. Ten males completed 3 test sessions:1) BS and HS 1RM, 2) HS & BS neuromuscular test familiarization, and, 3) Neuromuscular test for 3 reps at 4 loads for BS and HS. BS TMA was significantly greater (p<0.05) than HS for all muscles and phases except rectus abdominus in concentric phase. TMA increased (p<0.05) with load in all muscles for both exercises and phases apart from lumbar sacral erector spinae in HS eccentric phase. Mean HS 1RM and submaximal loads were significantly (p<0.0001) higher than the equivalent BS loads. Duration of the eccentric phase was higher (p<0.01) in HS than BS but not different in concentric phase. Duration increased significantly (p<0.01) with load in both exercises and both phases. Despite higher absolute tests loads in HS, TMA was higher in BS. TMA is sensitive to load in both exercises. BS is more effective than HS in activating the muscles of the trunk and therefore arguably more effective in developing trunk strength and stability for dynamic athletic performance.

Anthropometry as a predictor of bench press performance done at different loads.

PubMed

Caruso, John F; Taylor, Skyler T; Lutz, Brant M; Olson, Nathan M; Mason, Melissa L; Borgsmiller, Jake A; Riner, Rebekah D

2012-09-01

The purpose of our study was to examine the ability of anthropometric variables (body mass, total arm length, biacromial width) to predict bench press performance at both maximal and submaximal loads. Our methods required 36 men to visit our laboratory and submit to anthropometric measurements, followed by lifting as much weight as possible in good form one time (1 repetition maximum, 1RM) in the exercise. They made 3 more visits in which they performed 4 sets of bench presses to volitional failure at 1 of 3 (40, 55, or 75% 1RM) submaximal loads. An accelerometer (Myotest Inc., Royal Oak MI) measured peak force, velocity, and power after each submaximal load set. With stepwise multivariate regression, our 3 anthropometric variables attempted to explain significant amounts of variance for 13 bench press performance indices. For criterion measures that reached significance, separate Pearson product moment correlation coefficients further assessed if the strength of association each anthropometric variable had with the criterion was also significant. Our analyses showed that anthropometry explained significant amounts (p < 0.05) of variance for 8 criterion measures. It was concluded that body mass had strong univariate correlations with 1RM and force-related measures, total arm length was moderately associated with 1RM and criterion variables at the lightest load, whereas biacromial width had an inverse relationship with the peak number of repetitions performed per set at the 2 lighter loads. Practical applications suggest results may help coaches and practitioners identify anthropometric features that may best predict various measures of bench press prowess in athletes.

Effect of loading on unintentional lifting velocity declines during single sets of repetitions to failure during upper and lower extremity muscle actions.

PubMed

Izquierdo, M; González-Badillo, J J; Häkkinen, K; Ibáñez, J; Kraemer, W J; Altadill, A; Eslava, J; Gorostiaga, E M

2006-09-01

The purpose of this study was to examine the effect of different loads on repetition speed during single sets of repetitions to failure in bench press and parallel squat. Thirty-six physical active men performed 1-repetition maximum in a bench press (1 RM (BP)) and half squat position (1 RM (HS)), and performed maximal power-output continuous repetition sets randomly every 10 days until failure with a submaximal load (60 %, 65 %, 70 %, and 75 % of 1RM, respectively) during bench press and parallel squat. Average velocity of each repetition was recorded by linking a rotary encoder to the end part of the bar. The values of 1 RM (BP) and 1 RM (HS) were 91 +/- 17 and 200 +/- 20 kg, respectively. The number of repetitions performed for a given percentage of 1RM was significantly higher (p < 0.001) in half squat than in bench press performance. Average repetition velocity decreased at a greater rate in bench press than in parallel squat. The significant reductions observed in the average repetition velocity (expressed as a percentage of the average velocity achieved during the initial repetition) were observed at higher percentage of the total number of repetitions performed in parallel squat (48 - 69 %) than in bench press (34 - 40 %) actions. The major finding in this study was that, for a given muscle action (bench press or parallel squat), the pattern of reduction in the relative average velocity achieved during each repetition and the relative number of repetitions performed was the same for all percentages of 1RM tested. However, relative average velocity decreased at a greater rate in bench press than in parallel squat performance. This would indicate that in bench press the significant reductions observed in the average repetition velocity occurred when the number of repetitions was over one third (34 %) of the total number of repetitions performed, whereas in parallel squat it was nearly one half (48 %). Conceptually, this would indicate that for a given exercise (bench press or squat) and percentage of maximal dynamic strength (1RM), the pattern of velocity decrease can be predicted over a set of repetitions, so that a minimum repetition threshold to ensure maximal speed performance is determined.

The development of a repetition-load scheme for the eccentric-only bench press exercise.

PubMed

Moir, Gavin L; Erny, Kyle F; Davis, Shala E; Guers, John J; Witmer, Chad A

2013-01-01

The purpose of the present study was to develop a repetition-load scheme for the eccentric-only bench press exercise. Nine resistance trained men (age: 21.6 ± 1.0 years; 1-repetition maximum [RM] bench press: 137.7 ± 30.4 kg) attended four testing sessions during a four week period. During the first session each subject's 1-RM bench press load utilizing the stretch-shortening cycle was determined. During the remaining sessions they performed eccentric-only repetitions to failure using supra-maximal loads equivalent to 110%, 120% and 130% of their 1-RM value with a constant cadence (30 reps·min(-1)). Force plates and a three dimensional motion analysis system were used during these final three sessions in order to evaluate kinematic and kinetic variables. More repetitions were completed during the 110% 1-RM condition compared to the 130% 1-RM condition (p=0.01). Mean total work (p=0.046) as well as vertical force (p=0.049), vertical work (p=0.017), and vertical power output (p=0.05) were significantly greater during the 130% 1-RM condition compared to the 110% 1-RM condition. A linear function was fitted to the number of repetitions completed under each load condition that allowed the determination of the maximum number of repetitions that could be completed under other supra-maximal loads. This linear function predicted an eccentric-only 1-RM in the bench press with a load equivalent to 164.8% 1-RM, producing a load of 227.0 ± 50.0 kg. The repetition-load scheme presented here should provide a starting point for researchers to investigate the kinematic, kinetic and metabolic responses to eccentric-only bench press workouts.

The Development of a Repetition-Load Scheme for the Eccentric-Only Bench Press Exercise

PubMed Central

Moir, Gavin L.; Erny, Kyle F.; Davis, Shala E.; Guers, John J.; Witmer, Chad A.

2013-01-01

The purpose of the present study was to develop a repetition-load scheme for the eccentric-only bench press exercise. Nine resistance trained men (age: 21.6 ± 1.0 years; 1-repetition maximum [RM] bench press: 137.7 ± 30.4 kg) attended four testing sessions during a four week period. During the first session each subject’s 1-RM bench press load utilizing the stretch-shortening cycle was determined. During the remaining sessions they performed eccentric-only repetitions to failure using supra-maximal loads equivalent to 110%, 120% and 130% of their 1-RM value with a constant cadence (30 reps·min−1). Force plates and a three dimensional motion analysis system were used during these final three sessions in order to evaluate kinematic and kinetic variables. More repetitions were completed during the 110% 1-RM condition compared to the 130% 1-RM condition (p=0.01). Mean total work (p=0.046) as well as vertical force (p=0.049), vertical work (p=0.017), and vertical power output (p=0.05) were significantly greater during the 130% 1-RM condition compared to the 110% 1-RM condition. A linear function was fitted to the number of repetitions completed under each load condition that allowed the determination of the maximum number of repetitions that could be completed under other supra-maximal loads. This linear function predicted an eccentric-only 1-RM in the bench press with a load equivalent to 164.8% 1-RM, producing a load of 227.0 ± 50.0 kg. The repetition-load scheme presented here should provide a starting point for researchers to investigate the kinematic, kinetic and metabolic responses to eccentric-only bench press workouts. PMID:24235981

Effects of Heavy Strength Training on Running Performance and Determinants of Running Performance in Female Endurance Athletes

PubMed Central

Vikmoen, Olav; Raastad, Truls; Seynnes, Olivier; Bergstrøm, Kristoffer; Ellefsen, Stian; Rønnestad, Bent R.

2016-01-01

Purpose The purpose of the current study was to investigate the effects of adding strength training to normal endurance training on running performance and running economy in well-trained female athletes. We hypothesized that the added strength training would improve performance and running economy through altered stiffness of the muscle-tendon complex of leg extensors. Methods Nineteen female endurance athletes [maximal oxygen consumption (VO2max): 53±3 ml∙kg-1∙min-1, 5.8 h weekly endurance training] were randomly assigned to either normal endurance training (E, n = 8) or normal endurance training combined with strength training (E+S, n = 11). The strength training consisted of four leg exercises [3 x 4–10 repetition maximum (RM)], twice a week for 11 weeks. Muscle strength, 40 min all-out running distance, running performance determinants and patellar tendon stiffness were measured before and after the intervention. Results E+S increased 1RM in leg exercises (40 ± 15%) and maximal jumping height in counter movement jump (6 ± 6%) and squat jump (9 ± 7%, p < 0.05). This was accompanied by increased muscle fiber cross sectional area of both fiber type I (13 ± 7%) and fiber type II (31 ± 20%) in m. vastus lateralis (p < 0.05), with no change in capillary density in m. vastus lateralis or the stiffness of the patellar tendon. Neither E+S nor E changed running economy, fractional utilization of VO2max or VO2max. There were also no change in running distance during a 40 min all-out running test in neither of the groups. Conclusion Adding heavy strength training to endurance training did not affect 40 min all-out running performance or running economy compared to endurance training only. PMID:26953893

Short-term Periodization Models: Effects on Strength and Speed-strength Performance.

PubMed

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

2015-10-01

Dividing training objectives into consecutive phases to gain morphological adaptations (hypertrophy phase) and neural adaptations (strength and power phases) is called strength-power periodization (SPP). These phases differ in program variables (volume, intensity, and exercise choice or type) and use stepwise intensity progression and concomitant decreasing volume, converging to peak intensity (peaking phase). Undulating periodization strategies rotate these program variables in a bi-weekly, weekly, or daily fashion. The following review addresses the effects of different short-term periodization models on strength and speed-strength both with subjects of different performance levels and with competitive athletes from different sports who use a particular periodization model during off-season, pre-season, and in-season conditioning. In most periodization studies, it is obvious that the strength endurance sessions are characterized by repetition zones (12-15 repetitions) that induce muscle hypertrophy in persons with a low performance level. Strictly speaking, when examining subjects with a low training level, many periodization studies include mainly hypertrophy sessions interspersed with heavy strength/power sessions. Studies have demonstrated equal or statistically significant higher gains in maximal strength for daily undulating periodization compared with SPP in subjects with a low to moderate performance level. The relatively short intervention period and the lack of concomitant sports conditioning call into question the practical value of these findings for competitive athletes. Possibly owing to differences in mesocycle length, conditioning programs, and program variables, competitive athletes either maintained or improved strength and/or speed-strength performance by integrating daily undulating periodization and SPP during off-season, pre-season and in-season conditioning. In high-performance sports, high-repetition strength training (>15) should be avoided because it does not provide an adequate training stimulus for gains in muscle cross-sectional area and strength performance. High-volume circuit strength training performed over 2 years negatively affected the development of the power output and maximal strength of the upper extremities in professional rugby players. Indeed, meta-analyses and results with weightlifters, American Football players, and throwers confirm the necessity of the habitual use of ≥80% 1 RM: (1) to improve maximal strength during the off-season and in-season in American Football, (2) to reach peak performance in maximal strength and vertical jump power during tapering in track-and-field, and (3) to produce hypertrophy and strength improvements in advanced athletes. The integration and extent of hypertrophy strength training in in-season conditioning depend on the duration of the contest period, the frequency of the contests, and the proportion of the conditioning program. Based on the literature, 72 h between hypertrophy strength training and strength-power training should be provided to allow for adequate regeneration times and therefore maximal stimulus intensities in training. This conclusion is only valid if the muscle is not trained otherwise during this regeneration phase. Thus, rotating hypertrophy and strength-power sessions in a microcycle during the season is a viable option. Comparative studies in competitive athletes who integrated strength training during pre-season conditioning confirm a tendency for gains in explosive strength and statistically significant improvements in medicine ball throw through SPP but not through daily undulating periodization. These findings indicate that to maximize the speed-strength in the short term (peaking), elite athletes should perform strength-power training twice per week. It is possible to perform a single strength-power session with the method of maximum explosive strength actions moving high-weight loads (90% 1 repetition maximum [RM]) at least 1-2 days before competition because of the shorter regeneration times and potentiation effects. Compared with ballistic strength training (30% 1 RM), this method has been shown to provide statistically superior gains in maximal strength, peak power, impulse size, and explosive strength during tapering in track-and-field throwers. The speed-strength performance in drop jumps of strength-trained subjects showed potentiation effects 48-148 h after a single strength-power training session. Regarding neuromuscular performance, plyometric exercises can even be performed after strength-power training on the same day if a minimum rest period of 3 h is provided.

Positive effects of resistance training in frail elderly patients with dementia after long-term physical restraint.

PubMed

Cadore, Eduardo L; Moneo, Ana B Bays; Mensat, Marta Martinez; Muñoz, Andrea Rozas; Casas-Herrero, Alvaro; Rodriguez-Mañas, Leocadio; Izquierdo, Mikel

2014-04-01

This study investigated the effects of a multicomponent exercise intervention on muscle strength, incidence of falls and functional outcomes in frail elderly patients with dementia after long-term physical restraint, followed by 24 weeks of training cessation. Eighteen frail elderly patients with mild dementia (88.1 ± 5.1 years) performed a multicomponent exercise program, which consisted of 4 weeks of walking, balance and cognitive exercises, followed by 4 weeks of resistance exercise performed twice weekly [8-12 repetitions at 20-50 % of the one-repetition maximum (1RM)], combined with walking, balance and cognitive exercises. Before and after training, as well as after 24 weeks of training cessation, strength outcomes, Barthel Index, balance, gait ability, rise from a chair ability, dual task performance, incidence of falls and Mini-Mental State Examination were assessed. After the first 4 weeks of training, there was a significant improvement only in the balance test, whereas no additional changes were observed. However, after the second part of the training, the participants required significantly less time for the time-up-and-go test (P < 0.05), and improved the isometric hand grip, hip flexion and knee extension strength, as well as the leg press 1RM (P < 0.01). A significant reduction was also observed in the incidence of falls (P < 0.01). After 24 weeks of training cessation, abrupt decreases were observed in nearly all of the physical outcomes (P < 0.05). The exercise intervention improved strength, balance and gait ability in frail elderly patients with dementia after long-term physical restraint, and these benefits were lost after training cessation.

Heavy strength training improves running and cycling performance following prolonged submaximal work in well-trained female athletes.

PubMed

Vikmoen, Olav; Rønnestad, Bent R; Ellefsen, Stian; Raastad, Truls

2017-03-01

The purpose of this study was to investigate the effects of adding heavy strength training to female duathletes' normal endurance training on both cycling and running performance. Nineteen well-trained female duathletes ( V O 2max cycling: 54 ± 3 ml∙kg -1 ∙min -1 , VO 2max running: 53 ± 3 ml∙kg -1 ∙min -1 ) were randomly assigned to either normal endurance training ( E , n  = 8) or normal endurance training combined with strength training ( E+S , n  = 11). The strength training consisted of four lower body exercises [3 × 4-10 repetition maximum (RM)] twice a week for 11 weeks. Running and cycling performance were assessed using 5-min all-out tests, performed immediately after prolonged periods of submaximal work (3 h cycling or 1.5 h running). E+S increased 1RM in half squat (45 ± 22%) and lean mass in the legs (3.1 ± 4.0%) more than E Performance during the 5-min all-out test increased in both cycling (7.0 ± 4.5%) and running (4.7 ± 6.0%) in E+S, whereas no changes occurred in E The changes in running performance were different between groups. E+S reduced oxygen consumption and heart rate during the final 2 h of prolonged cycling, whereas no changes occurred in E No changes occurred during the prolonged running in any group. Adding strength training to normal endurance training in well-trained female duathletes improved both running and cycling performance when tested immediately after prolonged submaximal work. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Strength testing and training of rowers: a review.

PubMed

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

2011-05-01

In the quest to maximize average propulsive stroke impulses over 2000-m racing, testing and training of various strength parameters have been incorporated into the physical conditioning plans of rowers. Thus, the purpose of this review was 2-fold: to identify strength tests that were reliable and valid correlates (predictors) of rowing performance; and, to establish the benefits gained when strength training was integrated into the physical preparation plans of rowers. The reliability of maximal strength and power tests involving leg extension (e.g. leg pressing) and arm pulling (e.g. prone bench pull) was high (intra-class correlations 0.82-0.99), revealing that elite rowers were significantly stronger than their less competitive peers. The greater strength of elite rowers was in part attributed to the correlation between strength and greater lean body mass (r = 0.57-0.63). Dynamic lower body strength tests that determined the maximal external load for a one-repetition maximum (1RM) leg press (kg), isokinetic leg extension peak force (N) or leg press peak power (W) proved to be moderately to strongly associated with 2000-m ergometer times (r = -0.54 to -0.68; p < 0.05). Repetition tests that assess muscular or strength endurance by quantifying the number of repetitions accrued at a fixed percentage of the strength maximum (e.g. 50-70% 1RM leg press) or set absolute load (e.g. 40 kg prone bench pulls) were less reliable and more time consuming when compared with briefer maximal strength tests. Only leg press repetition tests were correlated with 2000-m ergometer times (e.g. r = -0.67; p < 0.05). However, these tests differentiate training experience and muscle morphology, in that those individuals with greater training experience and/or proportions of slow twitch fibres performed more repetitions. Muscle balance ratios derived from strength data (e.g. hamstring-quadriceps ratio <45% or knee extensor-elbow flexor ratio around 4.2 ± 0.22 to 1) appeared useful in the pathological assessment of low back pain or rib injury history associated with rowing. While strength partially explained variances in 2000-m ergometer performance, concurrent endurance training may be counterproductive to strength development over the shorter term (i.e. <12 weeks). Therefore, prioritization of strength training within the sequence of training units should be considered, particularly over the non-competition phase (e.g. 2-6 sets × 4-12 repetitions, three sessions a week). Maximal strength was sustained when infrequent (e.g. one or two sessions a week) but intense (e.g. 73-79% of maximum) strength training units were scheduled; however, it was unclear whether training adaptations should emphasize maximal strength, endurance or power in order to enhance performance during the competition phase. Additionally, specific on-water strength training practices such as towing ropes had not been reported. Further research should examine the on-water benefits associated with various strength training protocols, in the context of the training phase, weight division, experience and level of rower, if limitations to the reliability and precision of performance data (e.g. 2000-m time or rank) can be controlled. In conclusion, while positive ergometer time-trial benefits of clinical and practical significance were reported with strength training, a lack of statistical significance was noted, primarily due to an absence of quality long-term controlled experimental research designs.

Restoration of red mud deposits by naturally growing vegetation.

PubMed

Mishra, Tripti; Singh, N B; Singh, Nandita

2017-05-04

Disposal of red mud (RM) poses serious environmental problems such as wind erosion, air and water pollution. To overcome these problems, effective restoration of the disposal land through naturally growing vegetation is a sustainable and economical approach. The present study involved estimation of frequency (F), density (D), abundance (Ab), and important value index (IVI) of natural flora on abandoned RM sites in order to assess their metal toxicity tolerance capacity. Based on visual observations and highest IVI, S. Asper and S. punicea were identified as effective ecological tools for the restoration of barren RM sites. From the study, remarkable differences were observed between non-rhizospheric and rhizospheric RM of both species. These rhizospheric RM analyses confirm the ability of S. asper and S. punicea for enhancing the biological activities of abandoned RM. Translocation factor (TF) of iron was maximum (2.58) in S. asper, and bioconcentration factor (BCF) was found maximum (1.25) in S. punicea, but both TF (2.58) and BCF (1.35) were high in S. asper. Therefore, this plant could be reported as an iron hyperaccumulator plant. These results suggest that these plant species can be exploited for effective restoration of RM deposited land without any inputs or maintenance.

The impact of electronic mail versus print delivery of an exercise program on muscular strength and aerobic capacity in people with type 2 diabetes.

PubMed

Taylor, J David

2008-09-01

Previous research indicates that the Internet, electronic mail (e-mail), and printed materials can be used to deliver interventions to improve physical activity in people with type 2 diabetes. However, no studies have been conducted investigating the effect of e-mail or print delivery of an exercise program on muscular strength and aerobic capacity in people with type 2 diabetes. The purpose of this clinical trial was to investigate the impact of e-mail vs. print delivery of an exercise program on muscular strength and aerobic capacity in people with type 2 diabetes. Nineteen participants with type 2 diabetes were allocated to either a group that was delivered a prescribed exercise program using e-mail (e-mail group, n = 10) or a group that was delivered the same prescribed exercise program in print form (print group, n = 9). Chest press and leg press estimated one-repetition maximum (1-RM) scores as well as estimated peak oxygen uptake ([latin capital V with dot above]O2peak) were measured at baseline and follow-up. Intention-to-treat analysis indicated significant improvements in chest press (mean = 7.00 kg, p = 0.001, effect size = 2.22) and leg press (mean = 19.32 kg, p = 0.002, effect size = 1.98) 1-RM scores and [latin capital V with dot above]O2peak (mean = 9.38 mL of oxygen uptake per kilogram of body mass per minute, p = 0.01, effect size = 1.45) within the e-mail group. Within the print group, significant improvements in chest press (mean = 9.13 kg, p = 0.01, effect size = 1.49) and leg press (mean = 16.68 kg, p = 0.01, effect size = 1.31) 1-RM scores and [latin capital V with dot above]O2peak (mean = 5.14 ml of oxygen uptake per kilogram of body mass per minute, p = 0.03, effect size = 1.14) were found. No significant between-group differences in improvements were found. Clinicians can deliver a prescribed exercise program, either by e-mail or in print form, to significantly improve muscular strength and aerobic capacity in people with type 2 diabetes, and expect similar outcomes.

Epigenetic changes in leukocytes after 8 weeks of resistance exercise training.

PubMed

Denham, Joshua; Marques, Francine Z; Bruns, Emma L; O'Brien, Brendan J; Charchar, Fadi J

2016-06-01

Regular engagement in resistance exercise training elicits many health benefits including improvement to muscular strength, hypertrophy and insulin sensitivity, though the underpinning molecular mechanisms are poorly understood. The purpose of this study was to determine the influence 8 weeks of resistance exercise training has on leukocyte genome-wide DNA methylation and gene expression in healthy young men. Eight young (21.1 ± 2.2 years) men completed one repetition maximum (1RM) testing before completing 8 weeks of supervised, thrice-weekly resistance exercise training comprising three sets of 8-12 repetitions with a load equivalent to 80 % of 1RM. Blood samples were collected at rest before and after the 8-week training intervention. Genome-wide DNA methylation and gene expression were assessed on isolated leukocyte DNA and RNA using the 450K BeadChip and HumanHT-12 v4 Expression BeadChip (Illumina), respectively. Resistance exercise training significantly improved upper and lower body strength concurrently with diverse genome-wide DNA methylation and gene expression changes (p ≤ 0. 01). DNA methylation changes occurred at multiple regions throughout the genome in context with genes and CpG islands, and in genes relating to axon guidance, diabetes and immune pathways. There were multiple genes with increased expression that were enriched for RNA processing and developmental proteins. Growth factor genes-GHRH and FGF1-showed differential methylation and mRNA expression changes after resistance training. Our findings indicate that resistance exercise training improves muscular strength and is associated with reprogramming of the leukocyte DNA methylome and transcriptome.

Effect of movement velocity on the relationship between training load and the number of repetitions of bench press.

PubMed

Sakamoto, Akihiro; Sinclair, Peter J

2006-08-01

This study investigated the effect of movement velocity on the relationship between loading intensity and the number of repetitions of bench press. Thirteen healthy men (age = 21.7 +/- 1.0 years; weight = 76.8 +/- 2.5 kg; 1 repetition maximum [1RM] = 99.5 +/- 6.0 kg), who were involved in regular weight training, voluntarily participated in the experiment. Subjects performed bench presses on a Smith machine at 5 different intensities (40-80% 1RM), repeated for 4 velocity conditions (slow: 0.15 +/- 0.03 m.s(-1); medium: 0.32 +/- 0.07 m.s(-1); fast: 0.52 +/- 0.12 m.s(-1); ballistic: maximum velocity), which were randomly assigned over 5 experimental sessions after a 1RM test. Velocity significantly changed the relationship between intensity (%1RM) and the number of reps performed (p < 0.001), with faster velocities producing a higher number of reps. A significant interaction between intensity and velocity meant that velocity had a much greater effect on repetitions at lower intensities. These results suggest that the benefits of using a stretch-shortening cycle during faster movements outweigh the associated disadvantages from the force-velocity relationship. The practical applications of this study are that, when trainees are assigned a resistance training with specific RM values, the lifted intensity (%1RM) or weights will not be consistent unless velocity is controlled during training.

Progressive-overload whole-body vibration training as part of periodized, off-season strength training in trained women athletes.

PubMed

Jones, Margaret T

2014-09-01

The purpose was to examine the effects of progressive-overload, whole-body vibration (WBV) training on strength and power as part of a 15-week periodized, strength training (ST) program. Eighteen collegiate women athletes with ≥1 year of ST and no prior WBV training participated in the crossover design. Random assignment to 1 of the 2 groups followed pretests of seated medicine ball throw (SMBT), single-leg hop for distance (LSLH, RSLH), countermovement jump (CMJ), 3 repetition maximum (3RM) front squat (FS), pull-up (PU), and 3RM bench press (BP). Whole-body vibration was two 3-week phases of dynamic and static hold body weight exercises administered 2 d·wk in ST sessions throughout the 15-week off-season program. Total WBV exposure was 6 minutes broken into 30-second bouts with 60-second rest (1:2 work-to-relief ratio). Exercises, frequency, and amplitude progressed in intensity from the first 3-week WBV training to the second 3-week phase. Repeated-measures analysis of variances were used to analyze the SMBT, CMJ, LSLH, RSLH, FS, PU, and BP tests. Alpha level was p ≤ 0.05. Front squat, LSLH, and RSLH increased (p = 0.001) from pre- to posttest; FS increased from mid- to posttest. Pull-up increased (p = 0.008) from pre- to posttest. Seated medicine ball throw and BP showed a trend of increased performance from pre- to posttest (p = 0.11). Two 3-week phases of periodized, progressive-overload WBV + ST training elicited gains in strength and power during a 15-week off-season program. Greatest improvements in performance tests occurred in the initial WBV phase. Implementing WBV in conjunction with ST appears to be more effective in the early phases of training.

Using the load-velocity relationship for 1RM prediction.

PubMed

Jidovtseff, Boris; Harris, Nigel K; Crielaard, Jean-Michel; Cronin, John B

2011-01-01

The purpose of this study was to investigate the ability of the load-velocity relationship to accurately predict a bench press 1 repetition maximum (1RM). Data from 3 different bench press studies (n = 112) that incorporated both 1RM assessment and submaximal load-velocity profiling were analyzed. Individual regression analysis was performed to determine the theoretical load at zero velocity (LD0). Data from each of the 3 studies were analyzed separately and also presented as overall group mean. Thereafter, correlation analysis provided quantification of the relationships between 1RM and LD0. Practically perfect correlations (r = ∼0.95) were observed in our samples, confirming the ability of the load-velocity profile to accurately predict bench press 1RM.

Effects of 𝛽-Hydroxy-𝛽-methylbutyrate-free Acid Supplementation on Strength, Power and Hormonal Adaptations Following Resistance Training

PubMed Central

Asadi, Abbas; Arazi, Hamid

2017-01-01

Background: β-Hydroxy-β-methylbutyrate-free acid (HMB-FA) has been ingested prior to exercise to reduce muscle damage, however the effects of HMB-FA supplementation on hormonal, strength and power adaptation are unclear. Methods: Sixteen healthy men were matched and randomized into two groups and performed six-week resistance training while supplementing with either HMB-FA or placebo (3 g per day). The subjects were evaluated for 1 repetition maximum (1RM) bench press and leg press and vertical jump (VJ) prior to and after training intervention. In addition, blood samples were obtained before and after resistance training to evaluate resting growth hormone (GH), insulin like growth factor 1 (IGF-1), testosterone (TEST), cortisol (CORT), and adrenocorticotropic hormone (ACTH) responses. The HMB-FA supplementation group showed greater gains compared with the placebo group in peak power (effect size ES = 0.26 vs. 0.01) and 1RM leg press (ES = 1.52 vs. 0.96). In addition, the HMB-FA supplementation group indicated greater decrements in ACTH and CORT responses to training in comparison to the placebo group (p < 0.05). Likewise, in GH (ES = 1.41 vs. 0.12) and IGF-1 (ES = 0.83 vs. 0.41), the HMB-FA indicated greater training effects when compared with the placebo group. Conclusions: These findings provide further support for the potential anabolic benefits associated with HMB-FA supplementation. PMID:29207472

Vitamin C and E supplementation alters protein signalling after a strength training session, but not muscle growth during 10 weeks of training.

PubMed

Paulsen, G; Hamarsland, H; Cumming, K T; Johansen, R E; Hulmi, J J; Børsheim, E; Wiig, H; Garthe, I; Raastad, T

2014-12-15

This study investigated the effects of vitamin C and E supplementation on acute responses and adaptations to strength training. Thirty-two recreationally strength-trained men and women were randomly allocated to receive a vitamin C and E supplement (1000 mg day(-1) and 235 mg day(-1), respectively), or a placebo, for 10 weeks. During this period the participants' training involved heavy-load resistance exercise four times per week. Muscle biopsies from m. vastus lateralis were collected, and 1 repetition maximum (1RM) and maximal isometric voluntary contraction force, body composition (dual-energy X-ray absorptiometry), and muscle cross-sectional area (magnetic resonance imaging) were measured before and after the intervention. Furthermore, the cellular responses to a single exercise session were assessed midway in the training period by measurements of muscle protein fractional synthetic rate and phosphorylation of several hypertrophic signalling proteins. Muscle biopsies were obtained from m. vastus lateralis twice before, and 100 and 150 min after, the exercise session (4 × 8RM, leg press and knee-extension). The supplementation did not affect the increase in muscle mass or the acute change in protein synthesis, but it hampered certain strength increases (biceps curl). Moreover, increased phosphorylation of p38 mitogen-activated protein kinase, Extracellular signal-regulated protein kinases 1 and 2 and p70S6 kinase after the exercise session was blunted by vitamin C and E supplementation. The total ubiquitination levels after the exercise session, however, were lower with vitamin C and E than placebo. We concluded that vitamin C and E supplementation interfered with the acute cellular response to heavy-load resistance exercise and demonstrated tentative long-term negative effects on adaptation to strength training. © 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.

Creatine co-ingestion with carbohydrate or cinnamon extract provides no added benefit to anaerobic performance.

PubMed

Islam, Hashim; Yorgason, Nick J; Hazell, Tom J

2016-09-01

The insulin response following carbohydrate ingestion enhances creatine transport into muscle. Cinnamon extract is promoted to have insulin-like effects, therefore this study examined if creatine co-ingestion with carbohydrates or cinnamon extract improved anaerobic capacity, muscular strength, and muscular endurance. Active young males (n = 25; 23.7 ± 2.5 y) were stratified into 3 groups: (1) creatine only (CRE); (2) creatine+ 70 g carbohydrate (CHO); or (3) creatine+ 500 mg cinnamon extract (CIN), based on anaerobic capacity (peak power·kg(-1)) and muscular strength at baseline. Three weeks of supplementation consisted of a 5 d loading phase (20 g/d) and a 16 d maintenance phase (5 g/d). Pre- and post-supplementation measures included a 30-s Wingate and a 30-s maximal running test (on a self-propelled treadmill) for anaerobic capacity. Muscular strength was measured as the one-repetition maximum 1-RM for chest, back, quadriceps, hamstrings, and leg press. Additional sets of the number of repetitions performed at 60% 1-RM until fatigue measured muscular endurance. All three groups significantly improved Wingate relative peak power (CRE: 15.4% P = .004; CHO: 14.6% P = .004; CIN: 15.7%, P = .003), and muscular strength for chest (CRE: 6.6% P < .001; CHO: 6.7% P < .001; CIN: 6.4% P < .001), back (CRE: 5.8% P < .001; CHO: 6.4% P < .001; CIN: 8.1% P < .001), and leg press (CRE: 11.7% P = .013; CHO: 10.0% P = .007; CIN: 17.3% P < .001). Only the CRE (10.4%, P = .021) and CIN (15.5%, P < .001) group improved total muscular endurance. No differences existed between groups post-supplementation. These findings demonstrate that three different methods of creatine ingestion lead to similar changes in anaerobic power, strength, and endurance.

Validity and Reliability of a Wearable Inertial Sensor to Measure Velocity and Power in the Back Squat and Bench Press.

PubMed

Orange, Samuel T; Metcalfe, James W; Liefeith, Andreas; Marshall, Phil; Madden, Leigh A; Fewster, Connor R; Vince, Rebecca V

2018-05-08

Orange, ST, Metcalfe, JW, Liefeith, A, Marshall, P, Madden, LA, Fewster, CR, and Vince, RV. Validity and reliability of a wearable inertial sensor to measure velocity and power in the back squat and bench press. J Strength Cond Res XX(X): 000-000, 2018-This study examined the validity and reliability of a wearable inertial sensor to measure velocity and power in the free-weight back squat and bench press. Twenty-nine youth rugby league players (18 ± 1 years) completed 2 test-retest sessions for the back squat followed by 2 test-retest sessions for the bench press. Repetitions were performed at 20, 40, 60, 80, and 90% of 1 repetition maximum (1RM) with mean velocity, peak velocity, mean power (MP), and peak power (PP) simultaneously measured using an inertial sensor (PUSH) and a linear position transducer (GymAware PowerTool). The PUSH demonstrated good validity (Pearson's product-moment correlation coefficient [r]) and reliability (intraclass correlation coefficient [ICC]) only for measurements of MP (r = 0.91; ICC = 0.83) and PP (r = 0.90; ICC = 0.80) at 20% of 1RM in the back squat. However, it may be more appropriate for athletes to jump off the ground with this load to optimize power output. Further research should therefore evaluate the usability of inertial sensors in the jump squat exercise. In the bench press, good validity and reliability were evident only for the measurement of MP at 40% of 1RM (r = 0.89; ICC = 0.83). The PUSH was unable to provide a valid and reliable estimate of any other criterion variable in either exercise. Practitioners must be cognizant of the measurement error when using inertial sensor technology to quantify velocity and power during resistance training, particularly with loads other than 20% of 1RM in the back squat and 40% of 1RM in the bench press.

Effects of strength training on body composition, physical functioning, and quality of life in prostate cancer patients during androgen deprivation therapy.

PubMed

Nilsen, Tormod S; Raastad, Truls; Skovlund, Eva; Courneya, Kerry S; Langberg, Carl W; Lilleby, Wolfgang; Fosså, Sophie D; Thorsen, Lene

2015-11-01

Androgen deprivation therapy (ADT) increases survival rates in prostate cancer (PCa) patients with locally advanced disease, but is associated with side effects that may impair daily function. Strength training may counteract several side effects of ADT, such as changes in body composition and physical functioning, which in turn may affect health-related quality of life (HRQOL). However, additional randomised controlled trials are needed to expand this knowledge. Fifty-eight PCa patients on ADT were randomised to either 16 weeks of high-load strength training (n = 28) or usual care (n = 30). The primary outcome was change in total lean body mass (LBM) assessed by dual x-ray absorptiometry (DXA). Secondary outcomes were changes in regional LBM, fat mass, and areal bone mineral density (aBMD) measured by DXA; physical functioning assessed by 1-repetition maximum (1RM) tests, sit-to-stand test, stair climbing test and Shuttle walk test; and HRQOL as measured by the European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire Core 30. No statistically significant effect of high-load strength training was demonstrated on total LBM (p = 0.16), but significant effects were found on LBM in the lower and upper extremities (0.49 kg, p < 0.01 and 0.15 kg, p < 0.05, respectively). Compared to usual care, high-load strength training showed no effect on fat mass, aBMD or HRQOL, but beneficial effects were observed in all 1RM tests, sit-to-stand test and stair climbing tests. Adherence to the training program was 88% for lower body exercises and 84% for upper body exercises. In summary, high-load strength training improved LBM in extremities and physical functioning, but had no effect on fat mass, aBMD, or HRQOL in PCa patients on ADT.

Effect of eight weeks of upper-body plyometric training during the competitive season on professional female volleyball players.

PubMed

Valades, David; Palao, José M; Femia, Pedro; Ureña, Aurelio

2017-07-25

The purpose of this study was to assess the effect of incorporating specific upper-body plyometric training for the spike into the competitive season of a women's professional volleyball team. A professional team from the Spanish first division participated in the study. An A-B-A' quasi-experimental design with experimental and control groups was used. The independent variable was the upper-body plyometric training for eight weeks during the competitive season. The dependent variables were the spiked ball's speed (Km/h); the player's body weight (Kg), BMI (Kg/m2), and muscle percentage in arms (%); 1 repetition maximum (1RM) in the bench press (Kg); 1RM in the pullover (Kg); and overhead medicine ball throws of 1, 2, 3, 4, and 5 kg (m). Inter-player and inter-group statistical analyses of the results were carried out (Wilcoxon test and linear regression model). The experimental group significantly improved their spike speed 3.8% from phase A to phase B, and they maintained this improvement after the retention phase. No improvements were found in the control group. The experimental group presented a significant improvement from phase A to phase B in dominant arm muscle area (+10.8%), 1RM for the bench press (+8.41%), 1RM for the pullover (+14.75%), and overhead medicine ball throws with 1 kg (+7.19%), 2 kg (+7.69%), and 3 kg (+5.26%). The control group did not present differences in these variables. Data showed the plyometric exercises that were tested could be used by performance-level volleyball teams to improve spike speed. The experimental group increased their upper-body maximal strength, their power application, and spike speed.

The Effect of Different Resistance Training Load Schemes on Strength and Body Composition in Trained Men

PubMed Central

Lopes, Charles Ricardo; Aoki, Marcelo Saldanha; Crisp, Alex Harley; de Mattos, Renê Scarpari; Lins, Miguel Alves; da Mota, Gustavo Ribeiro; Schoenfeld, Brad Jon; Marchetti, Paulo Henrique

2017-01-01

Abstract The purpose of this study was to evaluate the impact of moderate-load (10 RM) and low-load (20 RM) resistance training schemes on maximal strength and body composition. Sixteen resistance-trained men were randomly assigned to 1 of 2 groups: a moderate-load group (n = 8) or a low-load group (n = 8). The resistance training schemes consisted of 8 exercises performed 4 times per week for 6 weeks. In order to equate the number of repetitions performed by each group, the moderate load group performed 6 sets of 10 RM, while the low load group performed 3 sets of 20 RM. Between-group differences were evaluated using a 2-way ANOVA and independent t-tests. There was no difference in the weekly total load lifted (sets × reps × kg) between the 2 groups. Both groups equally improved maximal strength and measures of body composition after 6 weeks of resistance training, with no significant between-group differences detected. In conclusion, both moderate-load and low-load resistance training schemes, similar for the total load lifted, induced a similar improvement in maximal strength and body composition in resistance-trained men. PMID:28828088

High doses of vitamin C plus E reduce strength training-induced improvements in areal bone mineral density in elderly men.

PubMed

Stunes, Astrid Kamilla; Syversen, Unni; Berntsen, Sveinung; Paulsen, Gøran; Stea, Tonje H; Hetlelid, Ken J; Lohne-Seiler, Hilde; Mosti, Mats Peder; Bjørnsen, Thomas; Raastad, Truls; Haugeberg, Glenn

2017-06-01

Resistance training is beneficial for maintaining bone mass. We aimed to investigate the skeletal effects of high doses of antioxidants [vitamin C + E (α-tocopherol)] supplementation during 12-week supervised strength training in healthy, elderly men METHODS: Design: double-blinded randomized placebo-controlled study. Participants followed a supervised, undulating periodic exercise program with weekly adjusted load: 3 sessions/week and 3-15 repetitions maximum (RM) sets/exercise. The control group (CG, n = 17, 67 ± 5 years) received placebo and the antioxidant group (AO, n = 16, 70 ± 7 years) 1000 mg vitamin C + 235 mg vitamin E, daily. Areal bone mineral density (aBMD) at whole body, lumbar spine (L1-L4), total hip, and femoral neck were measured by dual energy X-ray absorptiometry and muscle strength by 1RM. Serum analyses of bone-related factors and adipokines were performed. In the CG, total hip aBMD increased by 1.0% (CI: 0.3-1.7) versus pretest and lumbar spine aBMD increased by 0.9% (CI: -0.2 to 2.0) compared to the AO. In the CG, there was an increase in serum concentrations of insulin-like growth factor 1 [+27.3% (CI: -0.3 to 54.9)] and leptin [+31.2% (CI: 9.8-52.6)) versus pretest, and a decrease in sclerostin [-9.9% (CI: 4.4-15.3)] versus pretest and versus AO. Serum bone formation markers P1NP and osteocalcin increased in both groups, while the bone resorption marker CTX-1 remained unchanged. High doses of antioxidant supplementations may constrain the favorable skeletal benefits of 12 weeks of resistance exercise in healthy elderly men.

Comparison of Kinematics and Muscle Activation in Free-Weight Back Squat With and Without Elastic Bands.

PubMed

Saeterbakken, Atle H; Andersen, Vidar; van den Tillaar, Roland

2016-04-01

The purpose of the study was to compare kinematic muscle activation when performing 6 repetition maximum (6RM) squats using constant (free weights) or variable resistance (free weights + elastic bands). Twenty recreationally trained women were recruited with 4.6 ± 2.1 years of resistance training experience and a relative strength (6RM/body mass) of 1.1. After a familiarization session identifying the 6RM loads, the participants performed 6RM squats using constant and variable resistance in a randomized order. The total resistance in the variable resistance group was similar to the constant resistance in the presticking region (98%), but greater in the sticking region (105%) and the poststicking region (113%). In addition, the presticking barbell velocity was 21.0% greater using variable than constant resistance, but 22.8% lower in the poststicking region. No significant differences in muscle electromyographic activity, time occurrence, and vertical displacement between the squat modalities were observed, except for higher barbell displacement poststicking using variable resistance. It was concluded that, due to differences in total resistance in the different regions performing variable compared with constant resistance, greater barbell velocity was observed in the presticking region and lower resistance was observed in the poststicking region. However, the extra resistance in the sticking and poststicking regions during the variable resistance modality did not cause increased muscle activity. When performing squats with heavy resistance, the authors recommend using variable resistance, but we suggest increasing the percentage resistance from the elastic bands or using chains.

Resistance exercise prevents plantar flexor deconditioning during bed rest

NASA Technical Reports Server (NTRS)

Bamman, M. M.; Hunter, G. R.; Stevens, B. R.; Guilliams, M. E.; Greenisen, M. C.

1997-01-01

Because resistance exercise (REX) and unloading induce opposing neuromuscular adaptations, we tested the efficacy of REX against the effects of 14 d of bed rest unloading (BRU) on the plantar flexor muscle group. Sixteen men were randomly assigned to no exercise (NOE, N = 8) or REX (N = 8). REX performed 5 sets x 6-10 repetitions to failure of constant resistance concentric/eccentric plantar flexion every other day during BRU. One-repetition maximum (1RM) strength was tested on the training device. The angle-specific torque-velocity relationship across 5 velocities (0, 0.52, 1.05, 1.75, and 2.97 rad.s-1) and the full range-of-motion power-velocity relationship were assessed on a dynamometer. Torque-position analyses identified strength changes at shortened, neutral, and stretched muscle lengths. Concentric and eccentric contractile work were measured across ten repetitions at 1.05 rad.s-1. Maximal neural activation was measured by surface electromyography (EMG). 1RM decreased 9% in NOE and improved 11% in REX (P < 0.05). Concentric (0.52 and 1.05 rad.s-1), eccentric (0.52 and 2.97 rad.s-1), and isometric angle-specific torques decreased (P < 0.05) in NOE, averaging 18%, 17%, and 13%, respectively. Power dropped (P < 0.05) in NOE at three eccentric (21%) and two concentric (14%) velocities. REX protected angle-specific torque and average power at all velocities. Concentric and eccentric strength decreased at stretched (16%) and neutral (17%) muscle lengths (P < 0.05) in NOE while REX maintained or improved strength at all joint positions. Concentric (15%) and eccentric (11%) contractile work fell in NOE (P < 0.05) but not in REX. Maximal plantar flexor EMG did not change in either group. In summary, constant resistance concentric/eccentric REX completely prevented plantar flexor performance deconditioning induced by BRU. The reported benefits of REX should prove useful in prescribing exercise for astronauts in microgravity and for patients susceptible to functional decline during bed- or chair-bound hospital stays.

High-frequency resistance training is not more effective than low-frequency resistance training in increasing muscle mass and strength in well-trained men.

PubMed

Gomes, Gederson K; Franco, Cristiane M; Nunes, Paulo Ricardo P; Orsatti, Fábio L

2018-02-27

We studied the effects of two different weekly frequency resistance training (RT) protocols over eight weeks on muscle strength and muscle hypertrophy in well-trained men. Twenty-three subjects (age: 26.2±4.2 years; RT experience: 6.9±3.1 years) were randomly allocated into the two groups: low frequency (LFRT, n = 12) or high frequency (HFRT, n = 11). The LFRT performed a split-body routine, training each specific muscle group once a week. The HFRT performed a total-body routine, training all muscle groups every session. Both groups performed the same number of sets (10-15 sets) and exercises (1-2 exercise) per week, 8-12 repetitions maximum (70-80% of 1RM), five times per week. Muscle strength (bench press and squat 1RM) and lean tissue mass (dual-energy x-ray absorptiometry) were assessed prior to and at the end of the study. Results showed that both groups improved (p<0.001) muscle strength [LFRT and HFRT: bench press = 5.6 kg (95% Confidence Interval (CI): 1.9 - 9.4) and 9.7 kg (95%CI: 4.6 - 14.9) and squat = 8.0 kg (95%CI: 2.7 - 13.2) and 12.0 kg (95%CI: 5.1 - 18.1), respectively] and lean tissue mass (p = 0.007) [LFRT and HFRT: total body lean mass = 0.5 kg (95%CI: 0.0 - 1.1) and 0.8 kg (95%CI: 0.0 - 1.6), respectively] with no difference between groups (bench press, p = 0.168; squat, p = 0.312 and total body lean mass, p = 0.619). Thus, HFRT and LFRT are similar overload strategies for promoting muscular adaptation in well-trained subjects when the sets and intensity are equated per week.

Muscle power output properties using the stretch-shortening cycle of the upper limb and their relationships with a one-repetition maximum bench press.

PubMed

Miyaguchi, Kazuyoshi; Demura, Shinichi

2006-05-01

The purpose of this study was to examine the output properties of muscle power by the dominant upper limb using SSC, and the relationships between the power output by SSC and a one-repetition maximum bench press (1 RM BP) used as a strength indicator of the upper body. Sixteen male athletes (21.4+/-0.9 yr) participated in this study. They pulled a load of 40% of maximum voluntary contraction (MVC) at a stretch by elbow flexion of the dominant upper limb in the following three preliminary conditions: static relaxed muscle state (SR condition), isometric muscle contraction state (ISO condition), and using SSC (SSC condition). The velocity with a wire load via a pulley during elbow flexion was measured accurately using a power instrument with a rotary encoder, and the muscle power curve was drawn from the product of the velocity and load. Significant differences were found among all evaluation parameters of muscle power exerted from the above three conditions and the parameters regarding early power output during concentric contraction were larger in the SSC condition than the SR and ISO conditions. The parameters on initial muscle contraction velocity when only using SSC significantly correlated with 1 RM BP (r=0.60-0.62). The use of SSC before powerful elbow flexion may contribute largely to early explosive power output during concentric contraction. Bench press capacity relates to a development of the above early power output when using SSC.

Running stride peak forces inversely determine running economy in elite runners.

PubMed

Støren, Øyvind; Helgerud, Jan; Hoff, Jan

2011-01-01

The present study investigated the relationship between running economy (RE) at 15 km/h(-1) , 3.000-m race time, maximal strength, and a number of physiological, anthropometrical, and mechanical variables. The variables measured included RE, maximal oxygen consumption, heart rate, step length and frequency, contact time, and the peak horizontal and vertical forces of each step. Maximal strength was measured as the 1 repetition maximum (1RM) half-squat using a leg press machine. Eleven male elite endurance athletes with a V(O2)max of 75.8 ± 6.2 mL/kg(-1)/min(-1) participated in this study. After the anthropometric data were collected, they were tested for RE, running characteristics, and force measures on a level treadmill at 15 km/h(-1). The athletes wore contact soles, and the treadmill was placed on a force platform. Maximal oxygen consumption and 1RM were tested after the RE measurements. The sum of horizontal and vertical peak forces revealed a significant inverse correlation (p < 0.05) both with 3,000-m performance (R = 0.71) and RE (R = 0.66). Inverse correlations were also found (p < 0.05) between RE and body height (R = 0.61) and between RE and body fat percentage (R = 0.62). In conclusion, the sum of horizontal and vertical peak forces was found to be negatively correlated to running economy and 3,000-m running performance, indicating that avoiding vertical movements and high horizontal braking force is crucial for a positive development of RE.

Effects of upper-body sprint-interval training on strength and endurance capacities in female cross-country skiers

PubMed Central

Vandbakk, Kristine; Welde, Boye; Kruken, Andrea Hovstein; Baumgart, Julia; Ettema, Gertjan; Karlsen, Trine; Sandbakk, Øyvind

2017-01-01

This study compared the effects of adding upper-body sprint-intervals or continuous double poling endurance training to the normal training on maximal upper-body strength and endurance capacity in female cross-country skiers. In total, 17 female skiers (age: 18.1±0.8yr, body mass: 60±7 kg, maximal oxygen uptake (VO2max): 3.30±0.37 L.min-1) performed an 8-week training intervention. Here, either two weekly sessions of six to eight 30-s maximal upper-body double poling sprint-intervals (SIG, n = 8) or 45–75 min of continuous low-to-moderate intensity double poling on roller skis (CG, n = 9) were added to their training. Before and after the intervention, the participants were tested for physiological and kinematical responses during submaximal and maximal diagonal and double poling treadmill roller skiing. Additionally, we measured maximal upper-body strength (1RM) and average power at 40% 1RM in a poling-specific strength exercise. SIG improved absolute VO2max in diagonal skiing more than CG (8% vs 2%, p<0.05), and showed a tendency towards higher body-mass normalized VO2max (7% vs 2%, p = 0.07). Both groups had an overall improvement in double poling peak oxygen uptake (10% vs 6% for SIG and CG) (both p<0.01), but no group-difference was observed. SIG improved 1RM strength more than CG (18% vs 10%, p<0.05), while there was a tendency for difference in average power at 40% 1RM (20% vs 14%, p = 0.06). Oxygen cost and kinematics (cycle length and rate) in double poling and diagonal remained unchanged in both groups. In conclusion, our study demonstrates that adding upper-body sprint-interval training is more effective than continuous endurance training in improving upper-body maximal strength and VO2max. PMID:28241030

Predicting the Size and Timing of Sunspot Maximum for Cycle 24

NASA Technical Reports Server (NTRS)

Wilson, Robert M.

2010-01-01

For cycle 24, the minimum value of the 12-month moving average (12-mma) of the AA-geomagnetic index in the vicinity of sunspot minimum (AAm) appears to have occurred in September 2009, measuring about 8.4 nT and following sunspot minimum by 9 months. This is the lowest value of AAm ever recorded, falling below that of 8.9 nT, previously attributed to cycle 14, which also is the smallest maximum amplitude (RM) cycle of the modern era (RM = 64.2). Based on the method of Ohl (the preferential association between RM and AAm for an ongoing cycle), one expects cycle 24 to have RM = 55+/-17 (the +/-1 - sigma prediction interval). Instead, using a variation of Ohl's method, one based on using 2-cycle moving averages (2-cma), one expects cycle 23's 2-cma of RM to be about 115.5+/-8.7 (the +/-1 - sigma prediction interval), inferring an RM of about 62+/-35 for cycle 24. Hence, it seems clear that cycle 24 will be smaller in size than was seen in cycle 23 (RM = 120.8) and, likely, will be comparable in size to that of cycle 14. From the Waldmeier effect (the preferential association between the ascent duration (ASC) and RM for an ongoing cycle), one expects cycle 24 to be a slow-rising cycle (ASC > or equal to 48 months), having RM occurrence after December 2012, unless it turns out to be a statistical outlier.

Can common measures of core stability distinguish performance in a shoulder pressing task under stable and unstable conditions?

PubMed

Keogh, Justin W L; Aickin, Sam E; Oldham, Anthony R H

2010-02-01

The primary purpose of this study was to determine whether a range of static core stability (CS) measures could distinguish shoulder press performance in unstable vs. stable conditions. Thirty resistance-trained men gave informed consent to participate in this study. One-repetition maximum strength (from < 6 repetitions) was predicted in the seated shoulder dumbbell press performed in unstable (Swiss ball[SB]) and stable (back-support bench) environments. Three CS muscle endurance tests were performed, with 4 CS ratios also calculated. The degree of strength decrement, referred to as the instability strength level (ISL), was calculated by dividing the predicted 1RM Unstable score by the 1RM Stable score. All subjects were categorized as high (ISL > 0.90), moderate (0.85 < or = ISL < or = 0.90), or low (ISL < 0.85). Between-group differences for the high- and low-ISL groups were assessed using analysis of variance and effect sizes. Pearson product moment correlations were then performed to examine the relationships between the CS measures and the ISL for the entire group. No significant between-group differences (p = 0.132-0.999) or large effect sizes were observed for any of the CS measures. Trunk flexion endurance was the only CS measure significantly correlated to the ISL (r = 0.477). In line with muscular strength research, these results suggest that CS exhibits relatively high levels of task specificity and that CS performance in static single-joint exercises may not be highly related to that in more dynamic multijoint activities. Core stability training (with or without a SB) may therefore only lead to significant improvements in functional dynamic performance if the postures, mode and velocity of contraction performed in training, are similar to the competitive tasks.

Rest Interval Required for Power Training With Power Load in the Bench Press Throw Exercise.

PubMed

Hernández Davó, Jose L; Solana, Rafael Sabido; Sarabia Marín, Jose M; Fernández Fernández, Jaime; Moya Ramón, Manuel

2016-05-01

This study aimed to test the influence of various rest interval (RI) durations used between sets on power output performance and physiological and perceptual variables during a strength training session using 40% of the 1 repetition maximum (1RM) in the bench press throw exercise. Thirty-one college students (18 males and 13 females) took part in the study. The experimental protocol consists of 5 sets of 8 repetitions of the bench press throw exercise with a load representing 40% of 1RM. Subjects performed the experimental protocol on 3 different occasions, differing by the RI between sets (1, 2, or 3 minutes). During the sessions, power data (mean power and peak power), physiological (lactate concentration [La]) and perceptual (rating of perceived exertion) variables were measured. In addition, delayed onset muscular soreness was reported 24 and 48 hours after the training session. One-way repeated-measures analysis of variance showed that 1-minute RI entailed higher power decreases and greater increases in values of physiological and perceptual variables compared with both 2- and 3-minute RIs. Nevertheless, no differences were found between 2- and 3-minute RIs. Therefore, this study showed that, when training with 40% of 1RM in the bench press throw exercise, a 2-minute RI between sets can be enough to avoid significant decreases in power output. Consequently, training sessions' duration could be reduced without causing excessive fatigue, allowing additional time to focus on other conditioning priorities.

Perceived exertion responses to changing resistance training programming variables.

PubMed

Hiscock, Daniel J; Dawson, Brian; Peeling, Peter

2015-06-01

This study examined the influence of intensity (%1 repetition maximum [1RM]), tonnage (sets × repetitions × load), rate of fatigue (percentage decrement in repetitions from set to set), work rate (total tonnage per unit of time), rest interval (time between sets), time under load, and session duration on session rating of perceived exertion (sRPE: Borg's CR-10 scale). Here, participants performed a standardized lifting session of 5 exercises (bench press, leg press, lat pulldown, leg curl, and triceps pushdown) as either: (a) 3 sets × 8 repetitions × 3-minute recovery at 70% 1RM, (b) 3 sets × 14 repetitions × 3-minute recovery at 40% 1RM, (c) 3 sets × MNR (maximum number of repetitions) × 1-minute recovery at 70% 1RM, (d) 3 sets × MNR × 3-minute recovery at 70% 1RM, (e) 3 sets × MNR × 1-minute recovery at 40% 1RM, or (f) 3 sets × MNR × 3-minute recovery at 40% 1RM. The sRPE for session A (4 ± 1) was significantly higher than session B (2.5 ± 1), despite matched tonnage. Protocols involving MNR showed no significant difference in sRPE. Work rate was the only variable to significantly relate with sRPE (r = 0.45). Additionally, sRPE at 15-minute postexercise (5 ± 2) was not different to 30-minute postexercise (5 ± 2). In resistance training with matched tonnage and rest duration between sets, sRPE increases with intensity. In sets to volitional failure, sRPE is likely to be similar, regardless of intensity or rest duration between sets.

Relationship between traditional and ballistic squat exercise with vertical jumping and maximal sprinting.

PubMed

Requena, Bernardo; García, Inmaculada; Requena, Francisco; de Villarreal, Eduardo Sáez-Sáez; Cronin, John B

2011-08-01

The purpose of this study was to quantify the magnitude of the relationship between vertical jumping and maximal sprinting at different distances with performance in the traditional and ballistic concentric squat exercise in well-trained sprinters. Twenty-one men performed 2 types of barbell squats (ballistic and traditional) across different loads with the aim of determining the maximal peak and average power outputs and 1 repetition maximum (1RM) values. Moreover, vertical jumping (countermovement jump test [CMJ]) and maximal sprints over 10, 20, 30, 40, 60, and 80 m were also assessed. In respect to 1RM in traditional squat, (a) no significant correlation was found with CMJ performance; (b) positive strong relationships (p < 0.01) were obtained with all the power measures obtained during both ballistic and traditional squat exercises (r = 0.53-0.90); (c) negative significant correlations (r = -0.49 to -0.59, p < 0.05) were found with sprint times in all the sprint distances measured when squat strength was expressed as a relative value; however, in the absolute mode, no significant relationships were observed with 10- and 20-m sprint times. No significant relationship was found between 10-m sprint time and relative or absolute power outputs using either ballistic or traditional squat exercises. Sprint time at 20 m was only related to ballistic and traditional squat performance when power values were expressed in relative terms. Moderate significant correlations (r = -0.39 to -0.56, p < 0.05) were observed between sprint times at 30 and 40 m and the absolute/relative power measures attained in both ballistic and traditional squat exercises. Sprint times at 60 and 80 m were mainly related to ballistic squat power outputs. Although correlations can only give insights into associations and not into cause and effect, from this investigation, it can be seen that traditional squat strength has little in common with CMJ performance and that relative 1RM and power outputs for both squat exercises are statistically correlated to most sprint distances underlying the importance of strength and power to sprinting.

Effects of phosphatidic acid supplementation on muscle thickness and strength in resistance-trained men.

PubMed

Gonzalez, Adam M; Sell, Katie M; Ghigiarelli, Jamie J; Kelly, Christopher F; Shone, Edward W; Accetta, Matthew R; Baum, Jamie B; Mangine, Gerald T

2017-04-01

The purpose of this study was to investigate the effects of phosphatidic acid (PA) supplementation on muscle thickness and strength following an 8 week supervised resistance-training program. Fifteen resistance trained men (22.8 ± 3.5 years; 80.6 ± 8.7 kg; 178.1 ± 5.6 cm; 14.6% ± 8.8% body fat) were randomly assigned to a group that either consumed 750 mg of PA or a placebo (PL). Testing was carried out before (PRE) and after (POST) training/supplementation for muscle thickness and strength. Muscle thickness of the rectus femoris (RF), vastus lateralis (VL), biceps brachii (BB), and triceps brachii (TB) muscles were measured via ultrasonography, along with 1 repetition maximum (1RM) of squat, deadlift, and bench press. Analysis of covariance (ANCOVA), using PRE values as the covariate, did not reveal any group differences for measures of muscle thickness in the RF (PA: 3.6% ± 5.2%; PL: 3.2% ± 4.2%, p = 0.97), VL (PA: 23.4% ± 18.1%, PL: 12.5% ± 15.4%, p = 0.37), BB (PA: 3.7% ± 6.4%, PL: 9.6% ± 12.4%, p = 0.86), or TB (PA: 15.1% ± 17.9%, PL: 10.7% ± 19.3%, p = 0.79). Likewise, no group differences were observed in changes in squat (PA: 8.4% ± 4.1%, PL: 8.1% ± 4.2%, p = 0.79), deadlift (PA: 10.1% ± 10.1%, PL: 8.9% ± 9.5%, p = 0.66), or bench press (PA: 5.7% ± 5.5%, PL: 5.1% ± 3.0%, p = 0.76) exercises. Collectively, however, all participants experienced significant (p < 0.05) improvements in each measure of muscle thickness and strength. Results of this study suggest that PA supplementation, in combination with a 3 days·week -1 resistance-training program for 8 weeks, did not have a differential effect compared with PL on changes in muscle thickness or 1RM strength.

Heavy Resistance Training in Hypoxia Enhances 1RM Squat Performance

PubMed Central

Inness, Mathew W. H.; Billaut, François; Walker, Emily J.; Petersen, Aaron C.; Sweeting, Alice J.; Aughey, Robert J.

2016-01-01

Purpose: To determine if heavy resistance training in hypoxia (IHRT) is more effective at improving strength, power, and increasing lean mass than the same training in normoxia. Methods: A pair-matched, placebo-controlled study design included 20 resistance-trained participants assigned to IHRT (FIO2 0.143) or placebo (FIO2 0.20), (n = 10 per group). Participants were matched for strength and training. Both groups performed 20 sessions over 7 weeks either with IHRT or placebo. All participants were tested for 1RM, 20-m sprint, body composition, and countermovement jump pre-, mid-, and post-training and compared via magnitude-based inferences. Presentation of Results: Groups were not clearly different for any test at baseline. Training improved both absolute (IHRT: 13.1 ± 3.9%, effect size (ES) 0.60, placebo 9.8 ± 4.7%, ES 0.31) and relative 1RM (IHRT: 13.4 ± 5.1%, ES 0.76, placebo 9.7 ± 5.3%, ES 0.48) at mid. Similarly, at post both groups increased absolute (IHRT: 20.7 ± 7.6%, ES 0.74, placebo 14.1 ± 6.0%, ES 0.58) and relative 1RM (IHRT: 21.6 ± 8.5%, ES 1.08, placebo 13.2 ± 6.4%, ES 0.78). Importantly, the change in IHRT was greater than placebo at mid for both absolute [4.4% greater change, 90% Confidence Interval (CI) 1.0:8.0%, ES 0.21, and relative strength (5.6% greater change, 90% CI 1.0:9.4%, ES 0.31 (relative)]. There was also a greater change for IHRT at post for both absolute (7.0% greater change, 90% CI 1.3:13%, ES 0.33), and relative 1RM (9.2% greater change, 90% CI 1.6:14.9%, ES 0.49). Only IHRT increased countermovement jump peak power at Post (4.9%, ES 0.35), however the difference between IHRT and placebo was unclear (2.7, 90% CI –2.0:7.6%, ES 0.20) with no clear differences in speed or body composition throughout. Conclusion: Heavy resistance training in hypoxia is more effective than placebo for improving absolute and relative strength. PMID:27857693

The effect of heavy- vs. light-load jump squats on the development of strength, power, and speed.

PubMed

McBride, Jeffrey M; Triplett-McBride, Travis; Davie, Allan; Newton, Robert U

2002-02-01

The purpose of this investigation was to examine the effect of an 8-week training program with heavy- vs. light-load jump squats on various physical performance measures and electromyography (EMG). Twenty-six athletic men with varying levels of resistance training experience performed sessions of jump squats with either 30% (JS30, n = 9) or 80% (JS80, n = 10) of their one repetition maximum in the squat (1RM) or served as a control (C, n = 7). An agility test, 20-m sprint, and jump squats with 30% (30J), 55% (55J), and 80% (80J) of their 1RM were performed before and after training. Peak force, peak velocity (PV), peak power (PP), jump height, and average EMG (concentric phase) were calculated for the jumps. There were significant increases in PP and PV in the 30J, 55J, and 80J for the JS30 group (p

Feasibility of the Two-Point Method for Determining the One-Repetition Maximum in the Bench Press Exercise.

PubMed

García-Ramos, Amador; Haff, Guy Gregory; Pestaña-Melero, Francisco Luis; Pérez-Castilla, Alejandro; Rojas, Francisco Javier; Balsalobre-Fernández, Carlos; Jaric, Slobodan

2017-09-05

This study compared the concurrent validity and reliability of previously proposed generalized group equations for estimating the bench press (BP) one-repetition maximum (1RM) with the individualized load-velocity relationship modelled with a two-point method. Thirty men (BP 1RM relative to body mass: 1.08 0.18 kg·kg -1 ) performed two incremental loading tests in the concentric-only BP exercise and another two in the eccentric-concentric BP exercise to assess their actual 1RM and load-velocity relationships. A high velocity (≈ 1 m·s -1 ) and a low velocity (≈ 0.5 m·s -1 ) was selected from their load-velocity relationships to estimate the 1RM from generalized group equations and through an individual linear model obtained from the two velocities. The directly measured 1RM was highly correlated with all predicted 1RMs (r range: 0.847-0.977). The generalized group equations systematically underestimated the actual 1RM when predicted from the concentric-only BP (P <0.001; effect size [ES] range: 0.15-0.94), but overestimated it when predicted from the eccentric-concentric BP (P <0.001; ES range: 0.36-0.98). Conversely, a low systematic bias (range: -2.3-0.5 kg) and random errors (range: 3.0-3.8 kg), no heteroscedasticity of errors (r 2 range: 0.053-0.082), and trivial ES (range: -0.17-0.04) were observed when the prediction was based on the two-point method. Although all examined methods reported the 1RM with high reliability (CV≤5.1%; ICC≥0.89), the direct method was the most reliable (CV<2.0%; ICC≥0.98). The quick, fatigue-free, and practical two-point method was able to predict the BP 1RM with high reliability and practically perfect validity, and therefore we recommend its use over generalized group equations.

The Relationship Between Maximum Unilateral Squat Strength and Balance in Young Adult Men and Women

PubMed Central

McCurdy, Kevin; Langford, George

2006-01-01

The purpose of this study was to determine the relationship between unilateral squat strength and measures of static balance to compare balance performance between the dominant and non-dominant leg. Seventeen apparently healthy men (mean mass 90.5 ± 20.9 kg and age 21.7 ± 1.8 yrs) and 25 women (mean mass 62.2 ± 14.5 kg and age 21.9 ± 1.3 yrs) completed the study. Weight bearing unilateral strength was measured with a 1RM modified unilateral squat on the dominant and non-dominant leg. The students completed the stork stand and wobble board tests to determine static balance on the dominant and non-dominant leg. Maximum time maintained in the stork stand position, on the ball of the foot with the uninvolved foot against the involved knee with hands on the hips, was recorded. Balance was measured with a 15 second wobble board test. No significant correlations were found between the measurements of unilateral balance and strength (r values ranged between -0.05 to 0.2) for the men and women. Time off balance was not significantly different between the subjects’ dominant (men 1.1 ± 0.4 s; women 0.3 ± 0.1 s) and non-dominant (men 0.9 ± 0.3 s; women 0.3 ± 0.1 s) leg for the wobble board. Similar results were found for the time balanced during the stork stand test on the dominant (men 26.4 ± 6.3 s; women 24.1 ± 5.6 s) and non-dominant (men 26.0 ± 5.7 s; women 21.3 ± 4.1 s) leg. The data indicate that static balance and strength is unrelated in young adult men and women and gains made in one variable after training may not be associated with a change in performance of the other variable. These results also suggest that differences in static balance performance between legs can not be determined by leg dominance. Similar research is needed to compare contralateral leg balance in populations who participate in work or sport activities requiring repetitive asymmetrical use. A better understanding of contralateral balance performance will help practitioners make evaluative decisions during the rehabilitation process. Key Points 1RM unilateral squat strength is unrelated to measures of unilateral static balance in young adult men and women Static balance is similar between the dominant and non-dominant leg in young adult men and women Side-to-side differences in balance warrant assessment and training to correct imbalances prior to participation in activities that present a high risk for injury. PMID:24260001

The influence of isometric preload on power expressed during bench press in strength-trained men.

PubMed

Bartolomei, Sandro; Fukuda, David H; Hoffman, Jay R; Stout, Jeffrey R; Merni, Franco

2017-03-01

The purpose of this study was to compare the power expressed during the bench press exercise in resistance-trained men following different pre-activation conditions. Twenty-two trained men (age 24.1 ± 1.7 years, height 178.6 ± 6.1 cm, body mass 81.1 ± 10.6 kg) completed a maximal effort bench press (1-RM) test (100.0 kg ± 8.1 kg). In a subsequent assessment, each participant performed concentric bench press movements with loads of 20%, 30%, 40% and 50% of their 1-RM preceded by either a concentric contraction (CC), a low isometric preload (LIP; 70% 1-RM) or a high isometric preload (HIP; 100% 1-RM) conditions. All movements were performed in a Smith machine with a settable quick-release device. Participants performed all three conditions in randomized fashion. Results indicated that power outputs during the bench press exercise following HIP were significantly (p < 0.05) greater than CC at 20% 1-RM (+9%), 30% 1-RM (+16%) and 40% 1-RM (+14%), and LIP at 20% 1-RM (+4%), 30% 1-RM (+20%) and 40% 1-RM (+15%). No differences were found between conditions at 50% 1-RM. Area under the force-power curve with HIP was greater (p < 0.05) than with CC and LIP. In conclusion, results of this study indicate that the use of a HIP (100% 1-RM) in trained participants results in significantly greater power output during the concentric phase of a multi-joint exercise when compared to standard concentric movement.

Anthropometrical, physiological, and tracked power profiles of elite taekwondo athletes 9 weeks before the Olympic competition phase.

PubMed

Ball, Nick; Nolan, Emily; Wheeler, Keane

2011-10-01

Physiological, anthropometric, and power profiling data were retrospectively analyzed from 4 elite taekwondo athletes from the Australian National Olympic team 9 weeks from Olympic departure. Power profiling data were collected weekly throughout the 9-week period. Anthropometric skinfolds generated a lean mass index (LMI). Physiological tests included a squat jump and bench throw power profile, bleep test, 20-m sprint test, running VO2max test, and bench press and squat 3 repetition maximum (3RM) strength tests. After this, the athletes power, velocity, and acceleration profile during unweighted squat jumps and single-leg jumps were tracked using a linear position transducer. Increases in power, velocity, and acceleration between weeks and bilateral comparisons were analyzed. Athletes had an LMI of 37.1 ± 0.4 and were 173.9 ± 0.2 m and 67 ± 1.1 kg. Relatively weaker upper body (56 ± 11.97 kg 3RM bench press) compared to lower body strength (88 ± 2.89 kg 3RM squat) was shown alongside a VO2max of 53.29 ml(-1)·min(-1)·kg, and a 20-m sprint time of 3.37 seconds. Increases in all power variables for single-leg squat and squat jumps were found from the first session to the last. Absolute peak power in single-leg squat jumps increased by 13.4-16% for the left and right legs with a 12.9% increase in squat jump peak power. Allometrically scaled peak power showed greater increases for single-leg (right leg: 18.55%; left: 23.49%) and squat jump (14.49%). The athlete's weight did not change significantly throughout the 9-week mesocycle. Progressions in power increases throughout the weeks were undulating and can be related to the intensity of the prior week's training and athlete injury. This analysis has shown that a 9-week mesocycle before Olympic departure that focuses on core lifts has the ability to improve power considerably.

Effects of low-intensity bench press training with restricted arm muscle blood flow on chest muscle hypertrophy: a pilot study.

PubMed

Yasuda, Tomohiro; Fujita, Satoshi; Ogasawara, Riki; Sato, Yoshiaki; Abe, Takashi

2010-09-01

Single-joint resistance training with blood flow restriction (BFR) results in significant increases in arm or leg muscle size and single-joint strength. However, the effect of multijoint BFR training on both blood flow restricted limb and non-restricted trunk muscles remain poorly understood. To examine the impact of BFR bench press training on hypertrophic response to non-restricted (chest) and restricted (upper-arm) muscles and multi-joint strength, 10 young men were randomly divided into either BFR training (BFR-T) or non-BFR training (CON-T) groups. They performed 30% of one repetition maximal (1-RM) bench press exercise (four sets, total 75 reps) twice daily, 6 days week(-1) for 2 weeks. During the exercise session, subjects in the BFR-T group placed elastic cuffs proximally on both arms, with incremental increases in external compression starting at 100 mmHg and ending at 160 mmHg. Before and after the training, triceps brachii and pectoralis major muscle thickness (MTH), bench press 1-RM and serum anabolic hormones were measured. Two weeks of training led to a significant increase (P<0.05) in 1-RM bench press strength in BFR-T (6%) but not in CON-T (-2%). Triceps and pectoralis major MTH increased 8% and 16% (P<0.01), respectively, in BFR-T, but not in CON-T (-1% and 2%, respectively). There were no changes in baseline concentrations of anabolic hormones in either group. These results suggest that BFR bench press training leads to significant increases in muscle size for upper arm and chest muscles and 1-RM strength.

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.

Effects of adding a weekly eccentric-overload training session on strength and athletic performance in team-handball players.

PubMed

Sabido, Rafael; Hernández-Davó, Jose Luis; Botella, Javier; Navarro, Angel; Tous-Fajardo, Julio

2017-06-01

To investigate the influence of adding a weekly eccentric-overload training (EOT) session in several athletic performance's tests, 18 team-handball players were assigned either to an EOT (n = 11) or a Control (n = 7) group. Both groups continued to perform the same habitual strength training, but the EOT group added one session/week during a 7-week training programme consisting of four sets of eight repetitions for the bilateral half-squat and unilateral lunge exercises. The test battery included handball throwing velocity, maximum dynamic strength (1RM), countermovement jump (CMJ), 20 m sprint, triple hop for distance, and eccentric/concentric power in both the half-squat and lunge exercises. Data were analysed using magnitude-based inferences. Both groups improved their 1RM in the half squat, 20 m sprint time, and CMJ performance to a similar extent, but the EOT group showed a beneficial effect for both right [(42/58/0), possibly positive] and left [(99/1/0), very likely positive] triple hop for distance performance. In addition, the EOT group showed greater power output improvements in both eccentric and concentric phases of the half-squat (difference in percent of change ranging from 6.5% to 22.0%) and lunge exercises (difference in per cent of change ranging from 13.1% to 24.9%). Nevertheless, no group showed changes in handball throwing velocity. Selected variables related to team-handball performance (i.e. functional jumping performance, power output) can be improved by adding a single EOT session per week, highlighting the usefulness of this low-volume/high-intensity training when aiming at optimizing dynamic athletic performance.

Combined Aerobic/Strength Training and Energy Expenditure in Older Women

PubMed Central

Hunter, Gary R.; Bickel, C. Scott; Fisher, Gordon; Neumeier, William; McCarthy, John

2013-01-01

Purpose To examine the effects of three different frequencies of combined resistance and aerobic training on total energy expenditure (TEE) and activity related energy expenditure (AEE) in a group of older adults. Methods Seventy-two women, 60 – 74 years old, were randomly assigned to one of three groups: 1 day/week of aerobic and 1 day/week of resistance (1+1); 2 days/week of aerobic and 2 days/week resistance (2+2); or 3 days/week aerobic and 3 days/week resistance (3+3). Body composition (DXA), feeling of fatigue, depression, and vigor (questionnaire), strength (1RM), serum cytokines (ELISA), maximal oxygen uptake (progressive treadmill test), resting energy expenditure, and TEE were measured before and after 16 weeks of training. Aerobic training consisted of 40 minutes of aerobic exercise at 80% maximum heart rate and resistance training consisted of 2 sets of 10 repetitions for 10 different exercises at 80% of one repetition maximum. Results All groups increased fat free mass, strength and aerobic fitness and decreased fat mass. No changes were observed in cytokines or perceptions of fatigue/depression. No time by group interaction was found for any fitness/body composition variable. TEE and AEE increased with the 2+2 group but not with the other two groups. Non-exercise training AEE (NEAT) increased significantly in the 2+2 group (+200 kcal/day), group 1×1 showed a trend for an increase (+68 kcal/day) and group 3+3 decreased significantly (−150 kcal/day). Conclusion Results indicate that 3+3 training may inhibit NEAT by being too time consuming and does not induce superior training adaptations to 1+1 and 2+2 training. Key words: physical activity, older adults, total energy expenditure, maximum oxygen uptake. PMID:23774582

Effect of an herbal/botanical supplement on strength, balance, and muscle function following 12-weeks of resistance training: a placebo controlled study.

PubMed

Furlong, Jonathan; Rynders, Corey A; Sutherlin, Mark; Patrie, James; Katch, Frank I; Hertel, Jay; Weltman, Arthur

2014-01-01

StemSport (SS; StemTech International, Inc. San Clemente, CA) contains a proprietary blend of the botanical Aphanizomenon flos-aquae and several herbal antioxidant and anti-inflammatory substances. SS has been purported to accelerate tissue repair and restore muscle function following resistance exercise. Here, we examine the effects of SS supplementation on strength adaptations resulting from a 12-week resistance training program in healthy young adults. Twenty-four young adults (16 males, 8 females, mean age = 20.5 ± 1.9 years, mass = 70.9 ± 11.9 kg, stature = 176.6 ± 9.9 cm) completed the twelve week training program. The study design was a double-blind, placebo controlled parallel group trial. Subjects either received placebo or StemSport supplement (SS; mg/day) during the training. 1-RM bench press, 1-RM leg press, vertical jump height, balance (star excursion and center of mass excursion), isokinetic strength (elbow and knee flexion/extension) and perception of recovery were measured at baseline and following the 12-week training intervention. Resistance training increased 1-RM strength (p < 0.008), vertical jump height (p < 0.03), and isokinetic strength (p < 0.05) in both SS and placebo groups. No significant group-by-time interactions were observed (all p-values >0.10). These data suggest that compared to placebo, the SS herbal/botanical supplement did not enhance training induced adaptations to strength, balance, and muscle function above strength training alone.

Prediction of the Maximum Number of Repetitions and Repetitions in Reserve From Barbell Velocity.

PubMed

García-Ramos, Amador; Torrejón, Alejandro; Feriche, Belén; Morales-Artacho, Antonio J; Pérez-Castilla, Alejandro; Padial, Paulino; Haff, Guy Gregory

2018-03-01

To provide 2 general equations to estimate the maximum possible number of repetitions (XRM) from the mean velocity (MV) of the barbell and the MV associated with a given number of repetitions in reserve, as well as to determine the between-sessions reliability of the MV associated with each XRM. After determination of the bench-press 1-repetition maximum (1RM; 1.15 ± 0.21 kg/kg body mass), 21 men (age 23.0 ± 2.7 y, body mass 72.7 ± 8.3 kg, body height 1.77 ± 0.07 m) completed 4 sets of as many repetitions as possible against relative loads of 60%1RM, 70%1RM, 80%1RM, and 90%1RM over 2 separate sessions. The different loads were tested in a randomized order with 10 min of rest between them. All repetitions were performed at the maximum intended velocity. Both the general equation to predict the XRM from the fastest MV of the set (CV = 15.8-18.5%) and the general equation to predict MV associated with a given number of repetitions in reserve (CV = 14.6-28.8%) failed to provide data with acceptable between-subjects variability. However, a strong relationship (median r 2  = .984) and acceptable reliability (CV < 10% and ICC > .85) were observed between the fastest MV of the set and the XRM when considering individual data. These results indicate that generalized group equations are not acceptable methods for estimating the XRM-MV relationship or the number of repetitions in reserve. When attempting to estimate the XRM-MV relationship, one must use individualized relationships to objectively estimate the exact number of repetitions that can be performed in a training set.

Fluid-inclusion technique for determining maximum temperature in calcite and its comparison to the vitrinite reflectance geothermometer

USGS Publications Warehouse

Barker, C.E.; Goldstein, R.H.

1990-01-01

The hypothesis that aqueous fluid inclusions in calcite can be used to establish maximum temperature (Tpeak) is tested. Fluid inclusion Th, mean random vitrinite reflectance (Rm), and present-day Tpeak from 46 diverse geologic systems that have been at Tpeak from 104 to 106 yr have been compiled. Present Tpeak ranged from 65 to 345??C, Th modes and means ranged from 59 to 350??C, and Rm data ranged from 0.4% to 4.6%, spanning the temperature and thermal maturity range associated with burial diagenesis, hydrothermal alteration, and low-grade metamorphism. Plots of Th and Tpeak data for systems thought to be currently at maximum temperature demonstrate close agreement between Th and present Tpeak in sedimentary basins. The relation suggests that Th of aqueous fluid inclusions in calcite may be a useful measure of maximum temperature. This study also compared Th to mean random vitrinite reflectance (Rm). Th correlates well with Rm and results in a curve similar to Rm vs. Tpeak calibrations determined by other workers. Strong correlation between Tpeak and Rm in these systems suggests that maximum temperature is the major control on thermal maturation. -after Authors

The Effect of Aerobic or Aerobic-Strength Exercise on Body Composition and Functional Capacity in Patients with BMI ≥35 after Bariatric Surgery: a Randomized Control Trial.

PubMed

Hassannejad, Alireza; Khalaj, Alireza; Mansournia, Mohammad Ali; Rajabian Tabesh, Mastaneh; Alizadeh, Zahra

2017-11-01

Although previous studies suggested that bariatric surgery is the most effective and sustainable treatment method for morbid obesity in long term, but without changing in lifestyle, maintaining optimal weight loss is almost impossible. Sixty morbid obese patients (BMI ≥ 35) were evaluated before and after 12 weeks of bariatric surgery in order to compare the impact of two different exercise programs on body composition and functional capacity outcomes. Participants were divided into three groups: aerobic (A), aerobic-strength (AS), and control (C) group. Aerobic capacity was assessed with 12-min walk-run test (12MWRT). One-repetition maximum (1RM) test was performed to evaluation upper limb muscle strength. Lower extremity functional capacity was assessed by sit-to-stand test. Weight, percent body fat (PBF), and fat mass (FM) reduced greater in the trial groups in comparison to the C group (P < 0.05). In the AS group, the reduction of fat-free mass (FFM) was significantly lower than that in the other groups. Mean changes in 12MWRT increased significantly in the intervention groups. The mean change in the sit-to-stand scores was not statistically significant between the three groups. Comparing the intervention groups showed that mean changes in 1RM variables increased in AS group (P = 0.03). The data suggests a positive effect of exercise on weight and PBF decrease after surgery, and it leads to significant improvement on aerobic capacity. Moreover, doing resisted exercise caused greater preserving of lean mass.

The impact of strength level on adaptations to combined weightlifting, plyometric, and ballistic training.

PubMed

James, L P; Gregory Haff, G; Kelly, V G; Connick, M J; Hoffman, B W; Beckman, E M

2018-05-01

The purpose of this investigation was to determine whether the magnitude of adaptation to integrated ballistic training is influenced by initial strength level. Such information is needed to inform resistance training guidelines for both higher- and lower-level athlete populations. To this end, two groups of distinctly different strength levels (stronger: one-repetition-maximum (1RM) squat = 2.01 ± 0.15 kg·BM -1 ; weaker: 1.20 ± 0.20 kg·BM -1 ) completed 10 weeks of resistance training incorporating weightlifting derivatives, plyometric actions, and ballistic exercises. Testing occurred at pre-, mid-, and post-training. Measures included variables derived from the incremental-load jump squat and the 1RM squat, alongside muscle activity (electromyography), and jump mechanics (force-time comparisons throughout the entire movement). The primary outcome variable was peak velocity derived from the unloaded jump squat. It was revealed that the stronger group displayed a greater (P = .05) change in peak velocity at mid-test (baseline: 2.65 ± 0.10 m/s, mid-test: 2.80 ± 0.17 m/s) but not post-test (2.85 ± 0.18 m/s) when compared to the weaker participants (baseline 2.43 ± 0.09, mid-test. 2.47 ± 0.11, post-test: 2.61 ± 0.10 m/s). Different changes occurred between groups in the force-velocity relationship (P = .001-.04) and jump mechanics (P ≤ .05), while only the stronger group displayed increases in muscle activation (P = .05). In conclusion, the magnitude of improvement in peak velocity was significantly influenced by pre-existing strength level in the early stage of training. Changes in the mechanisms underpinning performance were less distinct. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Force-Velocity Relationship of Upper Body Muscles: Traditional Versus Ballistic Bench Press.

PubMed

García-Ramos, Amador; Jaric, Slobodan; Padial, Paulino; Feriche, Belén

2016-04-01

This study aimed to (1) evaluate the linearity of the force-velocity relationship, as well as the reliability of maximum force (F0), maximum velocity (V0), slope (a), and maximum power (P0); (2) compare these parameters between the traditional and ballistic bench press (BP); and (3) determine the correlation of F0 with the directly measured BP 1-repetition maximum (1RM). Thirty-two men randomly performed 2 sessions of traditional BP and 2 sessions of ballistic BP during 2 consecutive weeks. Both the maximum and mean values of force and velocity were recorded when loaded by 20-70% of 1RM. All force-velocity relationships were strongly linear (r > .99). While F0 and P0 were highly reliable (ICC: 0.91-0.96, CV: 3.8-5.1%), lower reliability was observed for V0 and a (ICC: 0.49-0.81, CV: 6.6-11.8%). Trivial differences between exercises were found for F0 (ES: < 0.2), however the a was higher for the traditional BP (ES: 0.68-0.94), and V0 (ES: 1.04-1.48) and P0 (ES: 0.65-0.72) for the ballistic BP. The F0 strongly correlated with BP 1RM (r: 0.915-0.938). The force-velocity relationship is useful to assess the upper body maximal capabilities to generate force, velocity, and power.

Effect of two different weight-loss rates on body composition and strength and power-related performance in elite athletes.

PubMed

Garthe, Ina; Raastad, Truls; Refsnes, Per Egil; Koivisto, Anu; Sundgot-Borgen, Jorunn

2011-04-01

When weight loss (WL) is necessary, athletes are advised to accomplish it gradually, at a rate of 0.5-1 kg/wk. However, it is possible that losing 0.5 kg/wk is better than 1 kg/wk in terms of preserving lean body mass (LBM) and performance. The aim of this study was to compare changes in body composition, strength, and power during a weekly body-weight (BW) loss of 0.7% slow reduction (SR) vs. 1.4% fast reduction (FR). We hypothesized that the faster WL regimen would result in more detrimental effects on both LBM and strength-related performance. Twenty-four athletes were randomized to SR (n = 13, 24 ± 3 yr, 71.9 ± 12.7 kg) or FR (n = 11, 22 ± 5 yr, 74.8 ± 11.7 kg). They followed energy-restricted diets promoting the predetermined weekly WL. All athletes included 4 resistance-training sessions/wk in their usual training regimen. The mean times spent in intervention for SR and FR were 8.5 ± 2.2 and 5.3 ± 0.9 wk, respectively (p < .001). BW, body composition (DEXA), 1-repetition-maximum (1RM) tests, 40-m sprint, and countermovement jump were measured before and after intervention. Energy intake was reduced by 19% ± 2% and 30% ± 4% in SR and FR, respectively (p = .003). BW and fat mass decreased in both SR and FR by 5.6% ± 0.8% and 5.5% ± 0.7% (0.7% ± 0.8% vs. 1.0% ± 0.4%/wk) and 31% ± 3% and 21 ± 4%, respectively. LBM increased in SR by 2.1% ± 0.4% (p < .001), whereas it was unchanged in FR (-0.2% ± 0.7%), with significant differences between groups (p < .01). In conclusion, data from this study suggest that athletes who want to gain LBM and increase 1RM strength during a WL period combined with strength training should aim for a weekly BW loss of 0.7%.

Effects of coffee and caffeine anhydrous on strength and sprint performance

PubMed Central

TREXLER, ERIC T.; SMITH-RYAN, ABBIE E.; ROELOFS, ERICA J.; HIRSCH, KATIE R.; MOCK, MEREDITH G.

2015-01-01

Caffeine and coffee are widely used among active individuals to enhance performance. The purpose of the current study was to compare the effects of acute coffee (COF) and caffeine anhydrous (CAF) intake on strength and sprint performance. Fifty-four resistance-trained males completed strength testing, consisting of one-rep max (1RM) and repetitions to fatigue (RTF) at 80% of 1RM for leg press (LP) and bench press (BP). Participants then completed five, ten-second cycle ergometer sprints separated by one minute of rest. Peak power (PP) and total work (TW) were recorded for each sprint. At least 48 hours later, participants returned and ingested a beverage containing CAF (300 mg flat dose; yielding 3–5 mg/kg bodyweight), COF (8.9 g; 303 mg caffeine), or placebo (PLA; 3.8 g noncaloric flavoring) 30 minutes before testing. LP 1RM was improved more by COF than CAF (p=0.04), but not PLA (p=0.99). Significant interactions were not observed for BP 1RM, BP RTF, or LP RTF (p>0.05). There were no sprint × treatment interactions for PP or TW (p>0.05). 95% confidence intervals revealed a significant improvement in sprint 1 TW for CAF, but not COF or PLA. For PLA, significant reductions were observed in sprint 4 PP, sprint 2 TW, sprint 4 TW, and average TW; significant reductions were not observed with CAF or COF. Neither COF nor CAF improved strength outcomes more than PLA, while both groups attenuated sprint power reductions to a similar degree. Coffee and caffeine anhydrous may be considered suitable pre-exercise caffeine sources for high-intensity exercise. PMID:26394649

Effects of coffee and caffeine anhydrous on strength and sprint performance.

PubMed

Trexler, Eric T; Smith-Ryan, Abbie E; Roelofs, Erica J; Hirsch, Katie R; Mock, Meredith G

2016-09-01

Caffeine and coffee are widely used among active individuals to enhance performance. The purpose of the current study was to compare the effects of acute coffee (COF) and caffeine anhydrous (CAF) intake on strength and sprint performance. Fifty-four resistance-trained males completed strength testing, consisting of one-rep max (1RM) and repetitions to fatigue (RTF) at 80% of 1RM for leg press (LP) and bench press (BP). Participants then completed five, 10-second cycle ergometer sprints separated by one minute of rest. Peak power (PP) and total work (TW) were recorded for each sprint. At least 48 hours later, participants returned and ingested a beverage containing CAF (300 mg flat dose; yielding 3-5 mg/kg bodyweight), COF (8.9 g; 303 mg caffeine), or placebo (PLA; 3.8 g non-caloric flavouring) 30 minutes before testing. LP 1RM was improved more by COF than CAF (p = .04), but not PLA (p = .99). Significant interactions were not observed for BP 1RM, BP RTF, or LP RTF (p > .05). There were no sprint × treatment interactions for PP or TW (p > .05). 95% confidence intervals revealed a significant improvement in sprint 1 TW for CAF, but not COF or PLA. For PLA, significant reductions were observed in sprint 4 PP, sprint 2 TW, sprint 4 TW, and average TW; significant reductions were not observed with CAF or COF. Neither COF nor CAF improved strength outcomes more than PLA, while both groups attenuated sprint power reductions to a similar degree. Coffee and caffeine anhydrous may be considered suitable pre-exercise caffeine sources for high-intensity exercise.

The influence of upper-body strength on flat-water sprint kayak performance in elite athletes.

PubMed

McKean, Mark R; Burkett, Brendan J

2014-07-01

Dry-land strength training is a fundamental component for elite kayak performance. The aims of this research were 3-fold: 1st, to determine the relationship between performance time and strength scores for elite kayakers; 2nd, to identify how strength changes (gains or losses) over 3 training y relate with changes in performance time for elite kayakers; and 3rd, to compare the progression in performance times for elite athletes with the top 3 performers from the national championships. The performance data for 15 elite male and 10 elite female kayakers were collected over 2 y. This group was reduced to 9 men and 8 women in the 3rd and final year. There were direct and significant correlations between strength scores and performance times across the 3 y. Bench-press 1RM increased by 34.8% for men and 42.3% for women. Over the 3 seasons, mean 1000-m time decreased by approximately 4.8%, 500-m times decreased by 7.3% (women), and 200-m times decreased by 9.1%. The women's 500-m changed from 11.9% difference from medalists to within 1.1% during the 3 y. During the 3 y of this study a change in 1-repetitionmaximum (1RM) bench press of 13% for men and 6.5% in women coincided with a change in performance times of 1%. For 1RM pull-up a change of 10% in men and 2.3% in women coincided with a change in performance times of 1%.

Effects of In-Season Explosive Strength Training on Maximal Leg Strength, Jumping, Sprinting, and Intermittent Aerobic Performance in Male Handball Athletes.

PubMed

Hermassi, Souhail; Chelly, Mohamed Souhaiel; Fieseler, Georg; Bartels, Thomas; Schulze, Stephan; Delank, Karl-Stefan; Shephard, Roy J; Schwesig, René

2017-09-01

Background  Team handball is an intense ball sport with specific requirements on technical skills, tactical understanding, and physical performance. The ability of handball players to develop explosive efforts (e. g. sprinting, jumping, changing direction) is crucial to success. Objective  The purpose of this pilot study was to examine the effects of an in-season high-intensity strength training program on the physical performance of elite handball players. Materials and methods  Twenty-two handball players (a single national-level Tunisian team) were randomly assigned to a control group (CG; n = 10) or a training group (TG; n = 12). At the beginning of the pilot study, all subjects performed a battery of motor tests: one repetition maximum (1-RM) half-squat test, a repeated sprint test [6 × (2 × 15 m) shuttle sprints], squat jumps, counter movement jumps (CMJ), and the Yo-Yo intermittent recovery test level 1. The TG additionally performed a maximal leg strength program twice a week for 10 weeks immediately before engaging in regular handball training. Each strength training session included half-squat exercises to strengthen the lower limbs (80 - 95 % of 1-RM, 1 - 3 repetitions, 3 - 6 sets, 3 - 4 min rest between sets). The control group underwent no additional strength training. The motor test battery was repeated at the end of the study interventions. Results  In the TG, 3 parameters (maximal strength of lower limb: η² = 0.74; CMJ: η² = 0.70, and RSA best time: η² = 0.25) showed significant improvements, with large effect sizes (e. g. CMJ: d = 3.77). A reduction in performance for these same 3 parameters was observed in the CG (d = -0.24). Conclusions  The results support our hypothesis that additional strength training twice a week enhances the maximal strength of the lower limbs and jumping or repeated sprinting performance. There was no evidence of shuttle sprints ahead of regular training compromising players' speed and endurance capacities. © Georg Thieme Verlag KG Stuttgart · New York.

Sex difference in the heat shock response to high external load resistance training in older humans.

PubMed

Njemini, Rose; Forti, Louis Nuvagah; Mets, Tony; Van Roie, Evelien; Coudyzer, Walter; Beyer, Ingo; Delecluse, Christophe; Bautmans, Ivan

2017-07-01

Literature reports on the effects of resistance training on heat shock protein70 (Hsp70) adaptation in older subjects are scarce. Moreover, the optimum training load required to obtain a beneficial adaptation profile is lacking. Therefore, the aim of this study was to determine the effects of resistance training at various external loads on extracellular Hsp70 (eHsp70) resting levels in older humans. Fifty-six community-dwelling older (68±5years) volunteers were randomized to 12weeks of resistance training (3×/week) at either high-resistance (HIGH, 8 males, 10 females, 2×10-15 repetitions at 80% 1RM), low resistance (LOW, 9 Males, 10 Females, 1×80-100 repetitions at 20% 1RM), or mixed low resistance (LOW+, 9 Males, 10 Females, 1×60 repetitions at 20% 1RM followed by 1×10-20 repetitions at 40% 1RM). Serum was available from 48 out of the 56 participants at baseline and after 12weeks for determination of eHsp70. Mid-thigh muscle volume (computed tomography), muscle strength (1RM & Biodex dynamometer) and physical functioning (including 6min walk distance [6MWD]) were assessed. There was a sex-related dichotomy in the heat shock response to high external load training. We observed a significant decrease in eHsp70 concentration in the HIGH group for female, but not male, subjects. At baseline, men had a larger muscle volume, leg press and leg extension 1RM compared to women (all p<0.001). Also, the 6MWD was significantly higher in men compared to women at baseline. However, this difference disappeared when correcting for height. Moreover, the overall functional performance and physical activity scores were similar in men and women. None of the participants' characteristics nor any of the outcome variables differed between groups at baseline. There was a significant increase in the strength and physical performance parameters in both men and women post-exercise (all p<0.05). Females in the HIGH group clearly demonstrated a larger gain in leg press 1RM and the isometric knee extensor strength compared to females in the LOW group (p=0.036 and p=0.044, respectively). More so, we found an inverse association between the change in eHsp70 levels and improvement in isometric knee extensor strength and 6MWD (r=-0.443, p=0.002 and r=-0.428, p=0.002; respectively) post exercise. Our results show that resistance training at high external load decreases the resting levels of eHsp70 in older females. Whether this reflects a better health status requires further investigation. Copyright © 2017 Elsevier Inc. All rights reserved.

Short- and Long-Term Effects of Concurrent Strength and HIIT Training in Octogenarians with COPD.

PubMed

Guadalupe-Grau, Amelia; Aznar-Laín, Susana; Mañas, Asier; Castellanos, Juan; Alcázar, Julián; Ara, Ignacio; Mata, Esmeralda; Daimiel, Rosa; García-García, Francisco José

2017-01-01

To investigate the short- and long-term effects of concurrent strength and high-intensity interval training (HIIT) on octogenarian COPD patients, nine males (age = 84.2 ± 2.8 years, BMI = 29.3 ± 2.3) with low to severe COPD levels (2.1 ± 1.5 BODE index) underwent a supervised 9-week strength and HIIT exercise program. Training had a significant (p < .05) impact on senior fitness test scores (23-45%), 30-m walking speed (from 1.29 ± 0.29-1.62 ± 0.33 m/s), leg and chest press 1RM (38% and 45% respectively), maximal isometric strength (30-35%), and 6-min walking test (from 286.1 ± 107.2-396.2 ± 106.5 m), and tended to increase predicted forced vital capacity by 14% (p = .07). One year after the intervention all training-induced gains returned to their preintervention values except for the chest press 1RM (p <.05). Short-term concurrent strength and HIIT training increases physical fitness in the oldest-old COPD patients, and has potential long-term benefits.

Effects of High-Velocity Resistance Training on Athletic Performance in Prepuberal Male Soccer Athletes.

PubMed

Negra, Yassine; Chaabene, Helmi; Hammami, Mehréz; Hachana, Younés; Granacher, Urs

2016-12-01

Negra, Y, Chaabene, H, Hammami, M, Hachana, Y, and Granacher, U. Effects of high-velocity resistance training on athletic performance in prepuberal male soccer athletes. J Strength Cond Res 30(12): 3290-3297, 2016-The aim of this study was to assess the effectiveness of a 12-week in-season low-to-moderate load high-velocity resistance training (HVRT) in addition to soccer training as compared with soccer training only on proxies of athletic performance in prepubertal soccer players. Twenty-four male soccer players performed 2 different protocols: (a) regular soccer training with 5 sessions per week (n = 11; age = 12.7 ± 0.3 years) and (b) regular soccer training with 3 sessions per week and HVRT with 2 sessions per week (n = 13; age = 12.8 ± 0.2 years). The outcome measures included tests for the assessment of muscle strength (e.g., 1 repetition maximum [1RM] half-squat tests), jump ability (e.g., countermovement jump, squat jump [SJ], standing long jump [SLJ], and multiple 5-bound tests [MB5s]), linear speed (e.g., 5-, 10-, 20-, and 30-m sprint tests), and change of direction (e.g., T-test and Illinois change of direction test). Results revealed significant group × test interactions for the SJ test (p ≤ 0.05, d = 0.59) and the SLJ test (p < 0.01, d = 0.83). Post hoc tests illustrated significant pre-post changes in the HVRT group (SJ: [INCREMENT]22%, p < 0.001, d = 1.26; SLJ: [INCREMENT]15%, p < 0.001, d = 1.30) but not in the control group. In addition, tendencies toward significant interaction effects were found for the 1RM half-squat (p = 0.08, d = 0.54) and the 10-m sprint test (p = 0.06, d = 0.57). Significant pre-post changes were found for both parameters in the HVRT group only (1RM: [INCREMENT]25%, p < 0.001, d = 1.23; 10-m sprint: [INCREMENT]7%, p < 0.0001, d = 1.47). In summary, in-season low-to-moderate load HVRT conducted in combination with regular soccer training is a safe and feasible intervention that has positive effects on maximal strength, vertical and horizontal jump and sprint performance as compared with soccer training only.

Muscular performance and body composition changes following multi-joint versus combined multi- and single-joint exercises in aging adults.

PubMed

Bezerra, Ewertton de Souza; Moro, Antônio Renato Pereira; Orssatto, Lucas Bet da Rosa; da Silva, Mariane Eichendorf; Willardson, Jeffrey Michael; Simão, Roberto

2018-06-01

The aim of the present study was to compare muscular performance and body composition changes following low-volume resistance-training programs consisting of multi-joint (MJ) exercises (cable chest press and seated row) versus a combination of multi- and single-joint (MJ+SJ) exercises (cable chest press, seated row, biceps curl, and triceps extension). Thirty untrained healthy aging adults were randomly assigned to 3 groups: MJ (n = 11), MJ+SJ (n = 11), and control (n = 8). Twelve-repetition maximums (12-RMs) for the cable chest press and seated row, localized muscular endurance for the elbow flexors handgrip strength, and body composition were assessed before and after the 8-week training program. All comparisons were analyzed via a mixed-model analysis with repeated measures (group × time) and the Bonferroni post hoc test (p < 0.05). The MJ and MJ+SJ groups increased performance in the 12-RM cable chest press (MJ = 61.5% ± 24.6% and MJ+SJ = 71.1% ± 25.6%), 12-RM seated row (MJ = 46.4% ± 26.3% and MJ+SJ = 51.5% ± 21.0%), localized muscular endurance (MJ = 24.7% ± 16.7% and MJ+SJ = 37.0% ± 11.4%), and handgrip strength (MJ = 9.3% ± 10.4% and MJ+SJ = 16.6% ± 25.3%) after the intervention. Body composition (i.e., trunk and upper limb fat and lean mass) did not change for any groups. No significant differences were observed between the MJ versus the MJ+SJ protocols after the intervention for any variables. In conclusion, for aging adults, either MJ or MJ+SJ low-volume resistance training resulted in similar increases in 12-RM, localized muscular endurance, and handgrip strength, without changes in body composition after 8 weeks of training.

A Comparison of Load-Velocity and Load-Power Relationships Between Well-Trained Young and Middle-Aged Males During Three Popular Resistance Exercises.

PubMed

Fernandes, John F T; Lamb, Kevin L; Twist, Craig

2018-05-01

Fernandes, JFT, Lamb, KL, and Twist, C. A comparison of load-velocity and load-power relationships between well-trained young and middle-aged males during 3 popular resistance exercises. J Strength Cond Res 32(5): 1440-1447, 2018-This study examined the load-velocity and load-power relationships among 20 young (age 21.0 ± 1.6 years) and 20 middle-aged (age 42.6 ± 6.7 years) resistance-trained males. Participants performed 3 repetitions of bench press, squat, and bent-over-row across a range of loads corresponding to 20-80% of 1 repetition maximum (1RM). Analysis revealed effects (p < 0.05) of group and load × group on barbell velocity for all 3 exercises, and interaction effects on power for squat and bent-over-row (p < 0.05). For bench press and bent-over-row, the young group produced higher barbell velocities, with the magnitude of the differences decreasing as load increased (ES; effect size 0.0-1.7 and 1.0-2.0, respectively). Squat velocity was higher in the young group than the middle-aged group (ES 1.0-1.7) across all loads, as was power for each exercise (ES 1.0-2.3). For all 3 exercises, both velocity and 1RM were correlated with optimal power in the middle-aged group (r = 0.613-0.825, p < 0.05), but only 1RM was correlated with optimal power (r = 0.708-0.867, p < 0.05) in the young group. These findings indicate that despite their resistance training, middle-aged males were unable to achieve velocities at low external loads and power outputs as high as the young males across a range of external resistances. Moreover, the strong correlations between 1RM and velocity with optimal power suggest that middle-aged males would benefit from training methods which maximize these adaptations.

Closed-kinetic chain upper-body training improves throwing performance of NCAA Division I softball players.

PubMed

Prokopy, Max P; Ingersoll, Christopher D; Nordenschild, Edwin; Katch, Frank I; Gaesser, Glenn A; Weltman, Arthur

2008-11-01

Closed-kinetic chain resistance training (CKCRT) of the lower body is superior to open-kinetic chain resistance training (OKCRT) to improve performance parameters (e.g., vertical jump), but the effects of upper-body CKCRT on throwing performance remain unknown. This study compared shoulder strength, power, and throwing velocity changes in athletes training the upper body exclusively with either CKCRT (using a system of ropes and slings) or OKCRT. Fourteen female National Collegiate Athletic Association Division I softball player volunteers were blocked and randomly placed into two groups: CKCRT and OKCRT. Blocking ensured the same number of veteran players and rookies in each training group. Training occurred three times weekly for 12 weeks during the team's supervised off-season program. Olympic, lower-body, core training, and upper-body intensity and volume in OKCRT and CKCRT were equalized between groups. Criterion variables pre- and posttraining included throwing velocity, bench press one-repetition maximum (1RM), dynamic single-leg balance, and isokinetic peak torque and power (PWR) (at 180 degrees x s(-1)) for shoulder flexion, extension, internal rotation, and external rotation (ER). The CKCRT group significantly improved throwing velocity by 2.0 mph (3.4%, p < 0.05), and the OKCRT group improved 0.3 mph (0.5%, NS). A significant interaction was observed (p < 0.05). The CKCRT group improved its 1RM bench press to the same degree (1.9 kg) as the OKCRT group (p < 0.05 within each group). The CKCRT group improved all measures of shoulder strength and power, whereas OKCRT conferred little change in shoulder torque and power scores. Although throwing is an open-chain movement, adaptations from CKCRT may confer benefits to subsequent performance. Strength coaches can incorporate upper-body CKCRT without sacrificing gains in maximal strength or performance criteria associated with an athletic open-chain movement such as throwing.

Validity and reliability of a novel iPhone app for the measurement of barbell velocity and 1RM on the bench-press exercise.

PubMed

Balsalobre-Fernández, Carlos; Marchante, David; Muñoz-López, Mario; Jiménez, Sergio L

2018-01-01

The purpose of this study was to analyse the validity and reliability of a novel iPhone app (named: PowerLift) for the measurement of mean velocity on the bench-press exercise. Additionally, the accuracy of the estimation of the 1-Repetition maximum (1RM) using the load-velocity relationship was tested. To do this, 10 powerlifters (Mean (SD): age = 26.5 ± 6.5 years; bench press 1RM · kg -1  = 1.34 ± 0.25) completed an incremental test on the bench-press exercise with 5 different loads (75-100% 1RM), while the mean velocity of the barbell was registered using a linear transducer (LT) and Powerlift. Results showed a very high correlation between the LT and the app (r = 0.94, SEE = 0.028 m · s -1 ) for the measurement of mean velocity. Bland-Altman plots (R 2  = 0.011) and intraclass correlation coefficient (ICC = 0.965) revealed a very high agreement between both devices. A systematic bias by which the app registered slightly higher values than the LT (P < 0.05; mean difference (SD) between instruments = 0.008 ± 0.03 m · s -1 ). Finally, actual and estimated 1RM using the app were highly correlated (r = 0.98, mean difference (SD) = 5.5 ± 9.6 kg, P < 0.05). The app was found to be highly valid and reliable in comparison with a LT. These findings could have valuable practical applications for strength and conditioning coaches who wish to measure barbell velocity in the bench-press exercise.

Neither load nor systemic hormones determine resistance training-mediated hypertrophy or strength gains in resistance-trained young men.

PubMed

Morton, Robert W; Oikawa, Sara Y; Wavell, Christopher G; Mazara, Nicole; McGlory, Chris; Quadrilatero, Joe; Baechler, Brittany L; Baker, Steven K; Phillips, Stuart M

2016-07-01

We reported, using a unilateral resistance training (RT) model, that training with high or low loads (mass per repetition) resulted in similar muscle hypertrophy and strength improvements in RT-naïve subjects. Here we aimed to determine whether the same was true in men with previous RT experience using a whole-body RT program and whether postexercise systemic hormone concentrations were related to changes in hypertrophy and strength. Forty-nine resistance-trained men (23 ± 1 yr, mean ± SE) performed 12 wk of whole-body RT. Subjects were randomly allocated into a higher-repetition (HR) group who lifted loads of ∼30-50% of their maximal strength (1RM) for 20-25 repetitions/set (n = 24) or a lower-repetition (LR) group (∼75-90% 1RM, 8-12 repetitions/set, n = 25), with all sets being performed to volitional failure. Skeletal muscle biopsies, strength testing, dual-energy X-ray absorptiometry scans, and acute changes in systemic hormone concentrations were examined pretraining and posttraining. In response to RT, 1RM strength increased for all exercises in both groups (P < 0.01), with only the change in bench press being significantly different between groups (HR, 9 ± 1, vs. LR, 14 ± 1 kg, P = 0.012). Fat- and bone-free (lean) body mass and type I and type II muscle fiber cross-sectional area increased following training (P < 0.01) with no significant differences between groups. No significant correlations between the acute postexercise rise in any purported anabolic hormone and the change in strength or hypertrophy were found. In congruence with our previous work, acute postexercise systemic hormonal rises are not related to or in any way indicative of RT-mediated gains in muscle mass or strength. Our data show that in resistance-trained individuals, load, when exercises are performed to volitional failure, does not dictate hypertrophy or, for the most part, strength gains. Copyright © 2016 the American Physiological Society.

Influence of recreational activity and muscle strength on ulnar bending stiffness in men

NASA Technical Reports Server (NTRS)

Myburgh, K. H.; Charette, S.; Zhou, L.; Steele, C. R.; Arnaud, S.; Marcus, R.

1993-01-01

Bone bending stiffness (modulus of elasticity [E] x moment of inertia [I]), a measure of bone strength, is related to its mineral content (BMC) and geometry and may be influenced by exercise. We evaluated the relationship of habitual recreational exercise and muscle strength to ulnar EI, width, and BMC in 51 healthy men, 28-61 yr of age. BMC and width were measured by single photon absorptiometry and EI by mechanical resistance tissue analysis. Maximum biceps strength was determined dynamically (1-RM) and grip strength isometrically. Subjects were classified as sedentary (S) (N = 13), moderately (M) (N = 18), or highly active (H) (N = 20) and exercised 0.2 +/- 0.2; 2.2 +/- 1.3; and 6.8 +/- 2.3 h.wk-1 (P < 0.001). H had greater biceps (P < 0.0005) and grip strength (P < 0.05), ulnar BMC (P < 0.05), and ulnar EI (P = 0.01) than M or S, who were similar. Amount of activity correlated with grip and biceps strength (r = 0.47 and 0.49; P < 0.001), but not with bone measurements, whereas muscle strength correlated with both EI and BMC (r = 0.40-0.52, P < 0.005). EI also correlated significantly with both BMC and ulnar width (P < 0.0001). Ulnar width and biceps strength were the only independent predictors of EI (r2 = 0.67, P < 0.0001). We conclude that levels of physical activity sufficient to increase arm strength influence ulnar bending stiffness.

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).

The effects of polyethylene glycosylated creatine supplementation on anaerobic performance measures and body composition.

PubMed

Camic, Clayton L; Housh, Terry J; Zuniga, Jorge M; Traylor, Daniel A; Bergstrom, Haley C; Schmidt, Richard J; Johnson, Glen O; Housh, Dona J

2014-03-01

The purpose of this study was to examine the effects of 28 days of polyethylene glycosylated creatine (PEG-creatine) supplementation (1.25 and 2.50 g·d) on anaerobic performance measures (vertical and broad jumps, 40-yard dash, 20-yard shuttle run, and 3-cone drill), upper- and lower-body muscular strength and endurance (bench press and leg extension), and body composition. This study used a randomized, double-blind, placebo-controlled parallel design. Seventy-seven adult men (mean age ± SD, 22.1 ± 2.5 years; body mass, 81.7 ± 10.8 kg) volunteered to participate and were randomly assigned to a placebo (n = 23), 1.25 g·d of PEG-creatine (n = 27), or 2.50 g·d of PEG-creatine (n = 27) group. The subjects performed anaerobic performance measures, muscular strength (one-repetition maximum [1RM]), and endurance (80% 1RM) tests for bench press and leg extension, and underwater weighing for the determination of body composition at day 0 (baseline), day 14, and day 28. The results indicated that there were improvements (p < 0.0167) in vertical jump, 20-yard shuttle run, 3-cone drill, muscular endurance for bench press, and body mass for at least one of the PEG-creatine groups without changes for the placebo group. Thus, the present results demonstrated that PEG-creatine supplementation at 1.25 or 2.50 g·d had an ergogenic effect on lower-body vertical power, agility, change-of-direction ability, upper-body muscular endurance, and body mass.

Comparison of Powerlifting Performance in Trained Men Using Traditional and Flexible Daily Undulating Periodization.

PubMed

Colquhoun, Ryan J; Gai, Christopher M; Walters, Jeoffrey; Brannon, Andrew R; Kilpatrick, Marcus W; DʼAgostino, Dominic P; Campbell, Bill I

2017-02-01

Colquhoun, RJ, Gai, CM, Walters, J, Brannon, AR, Kilpatrick, MW, D'Agostino, DP, and Campbell, WI. Comparison of powerlifting performance in trained men using traditional and flexible daily undulating periodization. J Strength Cond Res 31(2): 283-291, 2017-Daily undulating periodization (DUP) is a growing trend, both in practice and in the scientific literature. A new form of DUP, flexible daily undulating periodization (FDUP), allows for athletes to have some autonomy by choosing the order of their training. The purpose of this study was to compare an FDUP model to a traditional model of DUP on powerlifting performance in resistance-trained men. Twenty-five resistance-trained men were randomly assigned to one of 2 groups: FDUP (N = 14) or DUP (N = 11). All participants possessed a minimum of 6 months of resistance training experience and were required to squat, bench press, and deadlift 125, 100, and 150% of their body mass, respectively. Dependent variables assessed at baseline and after the 9-week training program included bench press 1 repetition maximum (1RM), squat 1RM, deadlift 1RM, powerlifting total, Wilks Coefficient, fat mass, and fat-free mass (FFM). Dependent variables assessed during each individual training session were motivation to train, Session Rating of Perceived Exertion (Session RPE), and satisfaction with training session. After the 9-week training program, no significant differences in intensity or volume were found between groups. Both groups significantly improved bench press 1RM (FDUP: +6.5 kg; DUP: +8.8 kg), squat 1RM (FDUP: +15.6 kg; DUP: +18.0 kg), deadlift 1RM (FDUP: +14.8 kg; DUP: +13.6 kg), powerlifting total (FDUP: +36.8 kg; DUP: +40.4 kg), and Wilks Coefficient (FDUP: +24.8; DUP: +26.0) over the course of study (p = <0.001 for each variable). There was also a significant increase in FFM (FDUP: +0.8 kg; DUP: +0.8 kg) for both groups (p = 0.003). There were no differences in motivation to train, session RPE, or satisfaction with training session measurements between groups (p = 0.369-0.702, respectively). In conclusion, FDUP seems to offer similar resistance training adaptations when compared with a traditional DUP in resistance-trained men.

Effect of an herbal/botanical supplement on strength, balance, and muscle function following 12-weeks of resistance training: a placebo controlled study

PubMed Central

2014-01-01

Background StemSport (SS; StemTech International, Inc. San Clemente, CA) contains a proprietary blend of the botanical Aphanizomenon flos-aquae and several herbal antioxidant and anti-inflammatory substances. SS has been purported to accelerate tissue repair and restore muscle function following resistance exercise. Here, we examine the effects of SS supplementation on strength adaptations resulting from a 12-week resistance training program in healthy young adults. Methods Twenty-four young adults (16 males, 8 females, mean age = 20.5 ± 1.9 years, mass = 70.9 ± 11.9 kg, stature = 176.6 ± 9.9 cm) completed the twelve week training program. The study design was a double-blind, placebo controlled parallel group trial. Subjects either received placebo or StemSport supplement (SS; mg/day) during the training. 1-RM bench press, 1-RM leg press, vertical jump height, balance (star excursion and center of mass excursion), isokinetic strength (elbow and knee flexion/extension) and perception of recovery were measured at baseline and following the 12-week training intervention. Results Resistance training increased 1-RM strength (p < 0.008), vertical jump height (p < 0.03), and isokinetic strength (p < 0.05) in both SS and placebo groups. No significant group-by-time interactions were observed (all p-values >0.10). Conclusions These data suggest that compared to placebo, the SS herbal/botanical supplement did not enhance training induced adaptations to strength, balance, and muscle function above strength training alone. PMID:24910543

The Effects of Eccentric, Velocity-Based Training on Strength and Power in Collegiate Athletes

PubMed Central

DOLEZAL, SAMANTHA M.; FRESE, DEREK L.; LLEWELLYN, TAMRA L.

2016-01-01

The purpose of this study was to determine if combining velocity-based training with eccentric focus (VEB) and velocity-based training (VBT) results in power and strength gains. Nineteen men and women collegiate track and field athletes participated in this study. The subjects completed a 12-week intervention with either a VEB program or a VBT program. To determine the effectiveness of each program, the subjects completed four exercise tests before and after the training period: vertical jump, medicine ball put test, 1RM projected bench press and 1RM projected squat. There were no significant differences between the VBT results and the VEB results. However, there were significant improvements between the pre-test and post-test measures for each group. There were increases in 1RM projected squat for VEB men, VBT men, and VBT women. There were also significant improvements in the VEB male vertical jump and medicine ball put test pre- to post-intervention. For track and field athletes, both programs may result in strength and power gains, however, the results cannot be used to conclude that one resistance training program is superior. PMID:27990226

The Effects of Eccentric, Velocity-Based Training on Strength and Power in Collegiate Athletes.

PubMed

Dolezal, Samantha M; Frese, Derek L; Llewellyn, Tamra L

2016-01-01

The purpose of this study was to determine if combining velocity-based training with eccentric focus (VEB) and velocity-based training (VBT) results in power and strength gains. Nineteen men and women collegiate track and field athletes participated in this study. The subjects completed a 12-week intervention with either a VEB program or a VBT program. To determine the effectiveness of each program, the subjects completed four exercise tests before and after the training period: vertical jump, medicine ball put test, 1RM projected bench press and 1RM projected squat. There were no significant differences between the VBT results and the VEB results. However, there were significant improvements between the pre-test and post-test measures for each group. There were increases in 1RM projected squat for VEB men, VBT men, and VBT women. There were also significant improvements in the VEB male vertical jump and medicine ball put test pre- to post-intervention. For track and field athletes, both programs may result in strength and power gains, however, the results cannot be used to conclude that one resistance training program is superior.

Low- and High-Resistance Exercise: Long-Term Adherence and Motivation among Older Adults.

PubMed

Van Roie, Evelien; Bautmans, Ivan; Coudyzer, Walter; Boen, Filip; Delecluse, Christophe

2015-01-01

In terms of motivation and long-term adherence, low-resistance exercise might be more suitable for older adults than high-resistance exercise. However, more data are needed to support this claim. The objective was to investigate the effect of low- and high-resistance exercise protocols on long-term adherence and motivation. This study was designed as an exploratory 24-week follow-up of a randomized 12-week resistance training intervention in older adults. Participants were free to decide whether or not they continued resistance training at their own expense following the intervention. Fifty-six older adults were randomly assigned to HIGH [2 × 10-15 repetitions at 80% of one repetition maximum (1RM)], LOW (1 × 80-100 repetitions at 20% of 1RM), or LOW+ (1 × 60 repetitions at 20% of 1RM + 1 × 10-20 repetitions at 40% 1RM). Motivation, self-efficacy and the perceived barriers for continuing resistance exercise were measured after cessation of each supervised intervention and at follow-up, while long-term adherence was probed retrospectively at follow-up. Participants reported high levels of self-determined motivation before, during, and after the supervised intervention, with no differences between groups (p > 0.05). Nevertheless, only few participants continued strength training after the intervention: 17% in HIGH, 21% in LOW+, and 11% in LOW (p > 0.05). The most commonly reported barriers for continuing resistance exercise were perceived lack of time (46%), being more interested in other physical activities (40%), seasonal reasons (40%), and financial cost (28%). The results suggest no difference in long-term adherence after the end of a supervised exercise intervention at high or low external resistances. Long-term adherence was limited despite high levels of self-determined motivation during the interventions. These findings highlight the importance of further research on developing strategies to overcome barriers of older adults to adhere to resistance exercise without supervision. © 2015 S. Karger AG, Basel.

Impact of resistance exercise during bed rest on skeletal muscle sarcopenia and myosin isoform distribution

NASA Technical Reports Server (NTRS)

Bamman, M. M.; Clarke, M. S.; Feeback, D. L.; Talmadge, R. J.; Stevens, B. R.; Lieberman, S. A.; Greenisen, M. C.

1998-01-01

Because resistance exercise (REx) and bed-rest unloading (BRU) are associated with opposing adaptations, our purpose was to test the efficacy of REx against the effects of 14 days of BRU on the knee-extensor muscle group. Sixteen healthy men were randomly assigned to no exercise (NoEx; n = 8) or REx (n = 8). REx performed five sets of leg press exercise with 80-85% of one repetition maximum (1 RM) every other day during BRU. Muscle samples were removed from the vastus lateralis muscle by percutaneous needle biopsy. Myofiber distribution was determined immunohistochemically with three monoclonal antibodies against myosin heavy chain (MHC) isoforms (I, IIa, IIx). MHC distribution was further assessed by quantitative gel electrophoresis. Dynamic 1-RM leg press and unilateral maximum voluntary isometric contraction (MVC) were determined. Maximal neural activation (root mean squared electromyogram) and rate of torque development (RTD) were measured during MVC. Reductions (P < 0.05) in type I (15%) and type II (17%) myofiber cross-sectional areas were found in NoEx but not in REx. Electrophoresis revealed no changes in MHC isoform distribution. The percentage of type IIx myofibers decreased (P < 0.05) in REx from 9 to 2% and did not change in NoEx. 1 RM was reduced (P < 0.05) by 9% in NoEx but was unchanged in REx. MVC fell by 15 and 13% in NoEx and REx, respectively. The agonist-to-antagonist root mean squared electromyogram ratio decreased (P < 0.05) 19% in REx. RTD slowed (P < 0.05) by 54% in NoEx only. Results indicate that REx prevented BRU-induced myofiber atrophy and also maintained training-specific strength. Unlike spaceflight, BRU did not induce shifts in myosin phenotype. The reported benefits of REx may prove useful in prescribing exercise for astronauts in microgravity.

Acute effects of heavy-load squats on consecutive squat jump performance.

PubMed

Weber, Kurt R; Brown, Lee E; Coburn, Jared W; Zinder, Steven M

2008-05-01

Postactivation potentiation (PAP) and complex training have generated interest within the strength and conditioning community in recent years, but much of the research to date has produced confounding results. The purpose of this study was to observe the acute effects of a heavy-load back squat [85% 1 repetition maximum (1RM)] condition on consecutive squat jump performance. Twelve in-season Division I male track-and-field athletes participated in two randomized testing conditions: a five-repetition back squat at 85% 1RM (BS) and a five-repetition squat jump (SJ). The BS condition consisted of seven consecutive squat jumps (BS-PRE), followed by five repetitions of the BS at 85% 1RM, followed by another set of seven consecutive squat jumps (BS-POST). The SJ condition was exactly the same as the BS condition except that five consecutive SJs replaced the five BSs, with 3 minutes' rest between each set. BS-PRE, BS-POST, SJ-PRE, and SJ-POST were analyzed and compared for mean and peak jump height, as well as mean and peak ground reaction force (GRF). The BS condition's mean and peak jump height and peak GRF increased 5.8% +/- 4.8%, 4.7% +/- 4.8%, and 4.6% +/- 7.4%, respectively, whereas the SJ condition's mean and peak jump height and peak GRF decreased 2.7% +/- 5.0%, 4.0% +/- 4.9%, and 1.3% +/- 7.5%, respectively. The results indicate that performing a heavy-load back squat before a set of consecutive SJs may enhance acute performance in average and peak jump height, as well as peak GRF.

Resistance Training with Single vs. Multi-joint Exercises at Equal Total Load Volume: Effects on Body Composition, Cardiorespiratory Fitness, and Muscle Strength.

PubMed

Paoli, Antonio; Gentil, Paulo; Moro, Tatiana; Marcolin, Giuseppe; Bianco, Antonino

2017-01-01

The present study aimed to compare the effects of equal-volume resistance training performed with single-joint (SJ) or multi-joint exercises (MJ) on VO 2 max, muscle strength and body composition in physically active males. Thirty-six participants were divided in two groups: SJ group ( n = 18, 182.1 ± 5.2, 80.03 ± 2.78 kg, 23.5 ± 2.7 years) exercised with only SJ exercises (e.g., dumbbell fly, knee extension, etc.) and MJ group ( n = 18, 185.3 ± 3.6 cm, 80.69 ± 2.98 kg, 25.5 ± 3.8 years) with only MJ exercises (e.g., bench press, squat, etc.). The total work volume (repetitions × sets × load) was equated between groups. Training was performed three times a week for 8 weeks. Before and after the training period, participants were tested for VO 2 max, body composition, 1 RM on the bench press, knee extension and squat. Analysis of covariance (ANCOVA) was used to compare post training values between groups, using baseline values as covariates. According to the results, both groups decreased body fat and increased fat free mass with no difference between them. Whilst both groups significantly increased cardiorespiratory fitness and maximal strength, the improvements in MJ group were higher than for SJ in VO 2 max (5.1 and 12.5% for SJ and MJ), bench press 1 RM (8.1 and 10.9% for SJ and MJ), knee extension 1 RM (12.4 and 18.9% for SJ and MJ) and squat 1 RM (8.3 and 13.8% for SJ and MJ). In conclusion, when total work volume was equated, RT programs involving MJ exercises appear to be more efficient for improving muscle strength and maximal oxygen consumption than programs involving SJ exercises, but no differences were found for body composition.

Effects of arachidonic acid supplementation on training adaptations in resistance-trained males

PubMed Central

Roberts, Michael D; Iosia, Mike; Kerksick, Chad M; Taylor, Lem W; Campbell, Bill; Wilborn, Colin D; Harvey, Travis; Cooke, Matthew; Rasmussen, Chris; Greenwood, Mike; Wilson, Ronald; Jitomir, Jean; Willoughby, Darryn; Kreider, Richard B

2007-01-01

Background To determine the impact of AA supplementation during resistance training on body composition, training adaptations, and markers of muscle hypertrophy in resistance-trained males. Methods In a randomized and double blind manner, 31 resistance-trained male subjects (22.1 ± 5.0 years, 180 ± 0.1 cm, 86.1 ± 13.0 kg, 18.1 ± 6.4% body fat) ingested either a placebo (PLA: 1 g·day-1 corn oil, n = 16) or AA (AA: 1 g·day-1 AA, n = 15) while participating in a standardized 4 day·week-1 resistance training regimen. Fasting blood samples, body composition, bench press one-repetition maximum (1RM), leg press 1RM and Wingate anaerobic capacity sprint tests were completed after 0, 25, and 50 days of supplementation. Percutaneous muscle biopsies were taken from the vastus lateralis on days 0 and 50. Results Wingate relative peak power was significantly greater after 50 days of supplementation while the inflammatory cytokine IL-6 was significantly lower after 25 days of supplementation in the AA group. PGE2 levels tended to be greater in the AA group. However, no statistically significant differences were observed between groups in body composition, strength, anabolic and catabolic hormones, or markers of muscle hypertrophy (i.e. total protein content or MHC type I, IIa, and IIx protein content) and other intramuscular markers (i.e. FP and EP3 receptor density or MHC type I, IIa, and IIx mRNA expression). Conclusion AA supplementation during resistance-training may enhance anaerobic capacity and lessen the inflammatory response to training. However, AA supplementation did not promote statistically greater gains in strength, muscle mass, or influence markers of muscle hypertrophy. PMID:18045476

Inter-relationships between machine squat-jump strength, force, power and 10 m sprint times in trained sportsmen.

PubMed

Harris, Nigel K; Cronin, J B; Hopkins, W G; Hansen, K T

2010-03-01

Strength and conditioning practitioners appear focussed on developing maximal strength based on the premise that it underpins explosive muscular performance. Investigation into the relationship between strength and a multitude of explosive power measures is limited though. Furthermore, the relationship of explosive force and power with functional performance is unclear. We examined the inter-relationships between maximal strength and explosive measures of force and power at different loads. Also investigated were the relationships between explosive measures and 10-m sprinting ability. Forty elite-level well-trained rugby union and league athletes performed 10-m sprints followed by bilateral concentric-only machine squat-jumps at 20 and 80%1RM. The magnitudes of the inter-relationships between groups of force measures, power measures and sprint times were interpreted using Pearson correlation coefficients, which had uncertainty (90% confidence limits) of approximately +/-0.25. Measures investigated included peak force, peak power, rate of force development, and some of Zatsiorsky's explosive measures, all expressed relative to body mass. The relationship between maximal strength and peak power was moderate at 20 %1RM (r=0.32) but trivial at 80 %1RM (r=-0.03). Practically no relationship between any of the explosive measures and 10-m sprint ability was observed (r=-0.01 to 0.06). Although correlations do not imply cause and effect, we speculate that the common practice of focussing on high levels of maximal strength in a machine squat to improve power output may be misguided. Our results also cast doubt on the efficacy of increasing explosive force and power in a machine squat-jump with the intention of improving sprint ability in well-trained athletes.

Differences in physical fitness and throwing velocity among elite and amateur male handball players.

PubMed

Gorostiaga, E M; Granados, C; Ibáñez, J; Izquierdo, M

2005-04-01

This study compared physical characteristics (body height, body mass [BM], body fat [BF], and free fatty mass [FFM]), one repetition maximum bench-press (1RM (BP)), jumping explosive strength (VJ), handball throwing velocity, power-load relationship of the leg and arm extensor muscles, 5- and 15-m sprint running time, and running endurance in two handball male teams: elite team, one of the world's leading teams (EM, n = 15) and amateur team, playing in the Spanish National Second Division (AM, n = 15). EM had similar values in body height, BF, VJ, 5- and 15-m sprint running time and running endurance than AM. However, the EM group gave higher values in BM (95.2 +/- 13 kg vs. 82.4 +/- 10 kg, p < 0.05), FFM (81.7 +/- 9 kg vs. 72.4 +/- 7 kg, p < 0.05), 1RM (BP) (107 +/- 12 kg vs. 83 +/- 10 kg, p < 0.001), muscle power during bench-press (18 - 21 %, p < 0.05) and half squat (13 - 17 %), and throwing velocities at standing (23.8 +/- 1.9 m . s (-1) vs. 21.8 +/- 1.6 m . s (-1), p < 0.05) and 3-step running (25.3 +/- 2.2 m . s (-1) vs. 22.9 +/- 1.4 m . s (-1), p < 0.05) actions than the AM group. Significant correlations (r = 0.67 - 0.71, p < 0.05 - 0.01) were observed in EM and AM between individual values of velocity at 30 % of 1RM (BP) and individual values of ball velocity during a standing throw. Significant correlations were observed in EM, but not in AM, between the individual values of velocity during 3-step running throw and the individual values of velocity at 30 % of 1RM (BP) (r = 0.72, p < 0.05), as well as the individual values of power at 100 % of body mass during half-squat actions (r = 0.62, p < 0.05). The present results suggest that more muscular and powerful players are at an advantage in handball. The differences observed in free fatty mass could partly explain the differences observed between groups in absolute maximal strength and muscle power. In EM, higher efficiency in handball throwing velocity may be associated with both upper and lower extremity power output capabilities, whereas in AM this relationship may be different. Endurance capacity does not seem to represent a limitation for elite performance in handball.

The Impact of a Multidimensional Exercise Intervention on Physical and Functional Capacity, Anxiety, and Depression in Patients With Advanced-Stage Lung Cancer Undergoing Chemotherapy.

PubMed

Quist, Morten; Adamsen, Lis; Rørth, Mikael; Laursen, Jørgen H; Christensen, Karl B; Langer, Seppo W

2015-07-01

Patients with advanced-stage lung cancer face poor survival and experience co-occurring chronic physical and psychosocial symptoms. Despite several years of research in exercise oncology, few exercise studies have targeted advanced lung cancer patients undergoing chemotherapy. The aim of the present study was to investigate the benefits of a 6-week supervised group exercise intervention and to outline the effect on aerobic capacity, strength, health-related quality of life (HRQoL), anxiety, and depression. VO2peak was assessed using an incremental exercise test. Muscle strength was measured with one repetition maximum test (1RM). HRQoL, anxiety, and depression were assessed using Functional Assessment of Cancer Therapy-Lung (FACT-L) scale and the Hospital Anxiety and Depression Scale (HADS). One hundred and forthteen patients with advanced stage lung cancer were recruited. Forty-three patients dropped out. No serious adverse events were reported. Exercise adherence in the group training was 68%. Improvements in VO2peak (P < .001) and 6-minute walk distance (P < .001) and muscle strength measurements (P < .05) were seen. There was a reduction in anxiety level (P = .0007) and improvement in the emotional well-being parameter (FACT-L) but no statistically significant changes in HRQoL were observed. The results of the present study show that during a 6-week hospital-based supervised, structured, and group-based exercise program, patients with advanced-stage lung cancer (NSCLC IIIb-IV, ED-SCLC) improve their physical capacity (VO2peak, 1RM), functional capacity, anxiety level, and emotional well-being, but not their overall HRQoL. A randomized controlled trial testing the intervention including 216 patients is currently being carried out. © The Author(s) 2015.

The effect from maximal bench press strength training on work economy during wheelchair propulsion in men with spinal cord injury.

PubMed

Tørhaug, T; Brurok, B; Hoff, J; Helgerud, J; Leivseth, G

2016-10-01

To assess the effect from maximal bench press strength training (MST) on wheelchair propulsion work economy (WE). Pretest-posttest case-control group design. St Olavs Hospital, Trondheim, Norway. Seventeen male individuals with spinal cord injury (SCI) paraplegia were allocated to either MST bench press (n=11) or the control group (CG) (n=7). The MST group trained bench press three times per week, for 6 weeks, starting at 85-95% of their pretest bench press one-repetition maximum (1RM). For calculation of WE during wheelchair propulsion, oxygen uptake (VO 2 ) measurements were collected during wheelchair ergometry (WCE) at submaximal workload of 50 W. Similarly, peak oxygen uptake (VO 2peak ) and peak power output (W) were measured during WCE. Individuals in the MST regimen significantly improved WE compared with the CG by 17.3 % (mean between-group differences: 95% confidence interval) of 2.63 ml kg -1  min -1 : (-4.34, -0.91) (P=0.007). Between pretest and posttest, the increase in bench press 1RM was by 17% higher in the MST group compared with the CG. At peak testing, the MST group generated significantly higher peak power compared with the CG. All other physiological variables were comparable within and between groups. A 6-week MST bench press regimen significantly improved WE during wheelchair propulsion at 50 W workload. These preliminary data support a possible beneficial role for MST to reduce the energy cost of wheelchair propulsion for SCI individuals.

Plasma boron and the effects of boron supplementation in males.

PubMed Central

Green, N R; Ferrando, A A

1994-01-01

Recently, a proliferation of athletic supplements has been marketed touting boron as an ergogenic aid capable of increasing testosterone. The effect of boron supplementation was investigated in male bodybuilders. Ten male bodybuilders (aged 20 to 26) were given a 2.5-mg boron supplement, while nine male bodybuilders (aged 21 to 27) were given a placebo for 7 weeks. Plasma total and free testosterone, plasma boron, lean body mass, and strength measurements were determined on day 1 and day 49 of the study. A microwave digestion procedure followed by inductively coupled argon plasma spectroscopy was used for boron determination. Twelve subjects had boron values at or above the detection limit with median value of 25 ng/ml (16 ng/ml lower quartile and 33 ng/ml upper quartile). Of the ten subjects receiving boron supplements, six had an increase in their plasma boron. Analysis of variance indicated no significant effect of boron supplementation on any of the other dependent variables. Both groups demonstrated significant increases in total testosterone (p < 0.01), lean body mass (p < 0.01), and one repetition maximum (RM) squat (p < 0.001) and one RM bench press (p < 0.01). The findings suggest that 7 weeks of bodybuilding can increase total testosterone, lean body mass, and strength in lesser-trained bodybuilders, but boron supplementation affects these variables not at all. PMID:7889885

Effects of oral ATP supplementation on anaerobic power and muscular strength.

PubMed

Jordan, Alexander N; Jurca, Radim; Abraham, Edward H; Salikhova, Anna; Mann, Julia K; Morss, Gina M; Church, Timothy S; Lucia, Alejandro; Earnest, Conrad P

2004-06-01

We examined 14 d of oral adenosine 5'-triphosphate (ATP) supplementation on indices of anaerobic capacity and muscular strength. Twenty-seven healthy males successfully completed the trial, after randomly receiving in a double-blind manner an oral dose of low dose (150 mg) or high dose (225 mg) ATP, or matched placebo. To improve absorption characteristics, the ATP was enterically coated. Total blood ATP (whole blood and plasma ATP) concentrations, two Wingate anaerobic power tests (30 s), and muscular strength (1RM and three sets of repetitions to fatigue at 70% of 1RM) were measured under three conditions: (i) baseline; (ii) acutely (7d later, no prior supplementation and 75 min after ATP ingestion); and (iii) after 14 d of daily ingestion (post). Statistical analyses showed no significant between or within group treatment effects for whole blood ATP or plasma ATP concentrations for any treatment condition. We also did not observe any treatment effects for any Wingate testing parameter including peak PO, total work, average PO for 30 s, or post-Wingate lactate accumulation. Overall, we observed no significant between group treatment effects for any muscular strength parameter. We did observe several within group differences for the group ingesting the high ATP dosage including 1RM (6.6%; P < 0.04) and repetitions to fatigue during set 1 of posttesting (18.5%; P < 0.007) and total lifting volume at post (22%; P < 0.003). We conclude that enterically coated oral ATP supplementation may provide small ergogenic effects on muscular strength under some treatment conditions.

Potentiation: Effect of Ballistic and Heavy Exercise on Vertical Jump Performance.

PubMed

Hester, Garrett M; Pope, Zachary K; Sellers, John H; Thiele, Ryan M; DeFreitas, Jason M

2017-03-01

Hester, GM, Pope, ZK, Sellers, JH, Thiele, RM, and DeFreitas, JM. Potentiation: Effect of ballistic and heavy exercise on vertical jump performance. J Strength Cond Res 31(3): 660-666, 2017-The purpose of this study was to compare the acute effects of heavy and ballistic conditioning protocols on vertical jump performance in resistance-trained men. Fourteen resistance-trained men (mean ± SD: age = 22 ± 2.1 years, body mass = 86.29 ± 9.95 kg, and height = 175.39 ± 9.34 cm) with an average relative full squat of 2.02 ± 0.28 times their body mass participated in this study. In randomized, counterbalanced order, subjects performed two countermovement vertical jumps before and 1, 3, 5, and 10 minutes after either performing 10 rapid jump squats or 5 heavy back squats. The back squat protocol consisted of 5 repetitions at 80% one repetition maximum (1RM), whereas the jump squat protocol consisted of 10 repetitions at 20% 1RM. Peak jump height (in centimeters) using a jump mat, along with power output (in Watts) and velocity (in meters per second) through a linear transducer, was recorded for each time interval. There was no significant condition × time interaction for any of the dependent variables (p = 0.066-0.127). In addition, there was no main effect for condition for any of the dependent variables (p = 0.457-0.899). Neither the ballistic nor heavy protocol used in this study enhanced vertical jump performance at any recovery interval. The use of these protocols in resistance-trained men to produce postactivation potentiation is not recommended.

Spectroscopic Classification of ASASSN-15rm as a Type Ia Supernova

NASA Astrophysics Data System (ADS)

Zheng, W.; Halevi, G.; Shivvers, I.; Yuk, H.; Filippenko, A. V.

2015-10-01

We report that inspection of a CCD spectrum (range 350-1050 nm) of ASASSN-15rm (ATel #8192), obtained on Oct. 20.50 UT with the Shane 3-m reflector (+ Kast spectrograph) at Lick Observatory, shows that the object is a normal Type Ia supernova roughly 1 week past maximum brightness.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Friedman, B.; DuCharme, G.

We present a semi-empirical scaling law for non-resonant ion–atom single charge exchange cross sections for collisions with velocities frommore » $${10}^{7}\\,{\\rm{t}}{\\rm{o}}\\,{10}^{9}\\,\\mathrm{cm}\\,{{\\rm{s}}}^{-1}$$ and ions with positive charge $$q\\lt 8$$. Non-resonant cross sections tend to have a velocity peak at collision velocities $$v\\lesssim 1\\ {\\rm{a}}{\\rm{u}}$$ with exponential decay around this peak. We construct a scaling formula for the location of this peak then choose a functional form for the cross section curve and scale it. The velocity at which the cross section peaks, v m, is proportional to the energy defect of the collision, $${\\rm{\\Delta }}E$$, which we predict with the decay approximation. The value of the cross section maximum is proportional to the charge state q, inversely proportional to the target ionization energy I T, and inversely proportional to v m. For the shape of the cross section curve, we use a function that decays exponentially asymptotically at high and low velocities. We scale this function with parameters $${v}_{{\\rm{m}}},{I}_{{\\rm{T}}},{Z}_{{\\rm{T}}},\\mathrm{and}\\ {Z}_{{\\rm{P}}}$$, where the $${Z}_{{\\rm{T}},{\\rm{P}}}$$ are the target and projectile atomic numbers. In conclusion, for the more than 100 cross section curves that we use to find the scaling rules, the scaling law predicts cross sections within a little over a factor of 2 on average.« less

Effects of instability versus traditional resistance training on strength, power and velocity in untrained men.

PubMed

Maté-Muñoz, José Luis; Monroy, Antonio J Antón; Jodra Jiménez, Pablo; Garnacho-Castaño, Manuel V

2014-09-01

The purpose of this study was compare the effects of a traditional and an instability resistance circuit training program on upper and lower limb strength, power, movement velocity and jumping ability. Thirty-six healthy untrained men were assigned to two experimental groups and a control group. Subjects in the experimental groups performed a resistance circuit training program consisting of traditional exercises (TRT, n = 10) or exercises executed in conditions of instability (using BOSU® and TRX®) (IRT, n = 12). Both programs involved three days per week of training for a total of seven weeks. The following variables were determined before and after training: maximal strength (1RM), average (AV) and peak velocity (PV), average (AP) and peak power (PP), all during bench press (BP) and back squat (BS) exercises, along with squat jump (SJ) height and counter movement jump (CMJ) height. All variables were found to significantly improve (p <0.05) in response to both training programs. Major improvements were observed in SJ height (IRT = 22.1%, TRT = 20.1%), CMJ height (IRT = 17.7%, TRT = 15.2%), 1RM in BS (IRT = 13.03%, TRT = 12.6%), 1RM in BP (IRT = 4.7%, TRT = 4.4%), AP in BS (IRT = 10.5%, TRT = 9.3%), AP in BP (IRT = 2.4%, TRT = 8.1%), PP in BS (IRT=19.42%, TRT = 22.3%), PP in BP (IRT = 7.6%, TRT = 11.5%), AV in BS (IRT = 10.5%, TRT = 9.4%), and PV in BS (IRT = 8.6%, TRT = 4.5%). Despite such improvements no significant differences were detected in the posttraining variables recorded for the two experimental groups. These data indicate that a circuit training program using two instability training devices is as effective in untrained men as a program executed under stable conditions for improving strength (1RM), power, movement velocity and jumping ability. Key PointsSimilar adaptations in terms of gains in strength, power, movement velocity and jumping ability were produced in response to both training programs.Both the stability and instability approaches seem suitable for healthy, physically-active individuals with or with limited experience in resistance training.RPE emerged as a useful tool to monitor exercise intensity during instability strength training.

Effects of Instability Versus Traditional Resistance Training on Strength, Power and Velocity in Untrained Men

PubMed Central

Maté-Muñoz, José Luis; Monroy, Antonio J. Antón; Jodra Jiménez, Pablo; Garnacho-Castaño, Manuel V.

2014-01-01

The purpose of this study was compare the effects of a traditional and an instability resistance circuit training program on upper and lower limb strength, power, movement velocity and jumping ability. Thirty-six healthy untrained men were assigned to two experimental groups and a control group. Subjects in the experimental groups performed a resistance circuit training program consisting of traditional exercises (TRT, n = 10) or exercises executed in conditions of instability (using BOSU® and TRX®) (IRT, n = 12). Both programs involved three days per week of training for a total of seven weeks. The following variables were determined before and after training: maximal strength (1RM), average (AV) and peak velocity (PV), average (AP) and peak power (PP), all during bench press (BP) and back squat (BS) exercises, along with squat jump (SJ) height and counter movement jump (CMJ) height. All variables were found to significantly improve (p <0.05) in response to both training programs. Major improvements were observed in SJ height (IRT = 22.1%, TRT = 20.1%), CMJ height (IRT = 17.7%, TRT = 15.2%), 1RM in BS (IRT = 13.03%, TRT = 12.6%), 1RM in BP (IRT = 4.7%, TRT = 4.4%), AP in BS (IRT = 10.5%, TRT = 9.3%), AP in BP (IRT = 2.4%, TRT = 8.1%), PP in BS (IRT=19.42%, TRT = 22.3%), PP in BP (IRT = 7.6%, TRT = 11.5%), AV in BS (IRT = 10.5%, TRT = 9.4%), and PV in BS (IRT = 8.6%, TRT = 4.5%). Despite such improvements no significant differences were detected in the posttraining variables recorded for the two experimental groups. These data indicate that a circuit training program using two instability training devices is as effective in untrained men as a program executed under stable conditions for improving strength (1RM), power, movement velocity and jumping ability. Key Points Similar adaptations in terms of gains in strength, power, movement velocity and jumping ability were produced in response to both training programs. Both the stability and instability approaches seem suitable for healthy, physically-active individuals with or with limited experience in resistance training. RPE emerged as a useful tool to monitor exercise intensity during instability strength training. PMID:25177170

Validity of Various Methods for Determining Velocity, Force, and Power in the Back Squat.

PubMed

Banyard, Harry G; Nosaka, Ken; Sato, Kimitake; Haff, G Gregory

2017-10-01

To examine the validity of 2 kinematic systems for assessing mean velocity (MV), peak velocity (PV), mean force (MF), peak force (PF), mean power (MP), and peak power (PP) during the full-depth free-weight back squat performed with maximal concentric effort. Ten strength-trained men (26.1 ± 3.0 y, 1.81 ± 0.07 m, 82.0 ± 10.6 kg) performed three 1-repetition-maximum (1RM) trials on 3 separate days, encompassing lifts performed at 6 relative intensities including 20%, 40%, 60%, 80%, 90%, and 100% of 1RM. Each repetition was simultaneously recorded by a PUSH band and commercial linear position transducer (LPT) (GymAware [GYM]) and compared with measurements collected by a laboratory-based testing device consisting of 4 LPTs and a force plate. Trials 2 and 3 were used for validity analyses. Combining all 120 repetitions indicated that the GYM was highly valid for assessing all criterion variables while the PUSH was only highly valid for estimations of PF (r = .94, CV = 5.4%, ES = 0.28, SEE = 135.5 N). At each relative intensity, the GYM was highly valid for assessing all criterion variables except for PP at 20% (ES = 0.81) and 40% (ES = 0.67) of 1RM. Moreover, the PUSH was only able to accurately estimate PF across all relative intensities (r = .92-.98, CV = 4.0-8.3%, ES = 0.04-0.26, SEE = 79.8-213.1 N). PUSH accuracy for determining MV, PV, MF, MP, and PP across all 6 relative intensities was questionable for the back squat, yet the GYM was highly valid at assessing all criterion variables, with some caution given to estimations of MP and PP performed at lighter loads.

Effect of creatine supplementation and drop-set resistance training in untrained aging adults.

PubMed

Johannsmeyer, Sarah; Candow, Darren G; Brahms, C Markus; Michel, Deborah; Zello, Gordon A

2016-10-01

To investigate the effects of creatine supplementation and drop-set resistance training in untrained aging adults. Participants were randomized to one of two groups: Creatine (CR: n=14, 7 females, 7 males; 58.0±3.0yrs, 0.1g/kg/day of creatine+0.1g/kg/day of maltodextrin) or Placebo (PLA: n=17, 7 females, 10 males; age: 57.6±5.0yrs, 0.2g/kg/day of maltodextrin) during 12weeks of drop-set resistance training (3days/week; 2 sets of leg press, chest press, hack squat and lat pull-down exercises performed to muscle fatigue at 80% baseline 1-repetition maximum [1-RM] immediately followed by repetitions to muscle fatigue at 30% baseline 1-RM). Prior to and following training and supplementation, assessments were made for body composition, muscle strength, muscle endurance, tasks of functionality, muscle protein catabolism and diet. Drop-set resistance training improved muscle mass, muscle strength, muscle endurance and tasks of functionality (p<0.05). The addition of creatine to drop-set resistance training significantly increased body mass (p=0.002) and muscle mass (p=0.007) compared to placebo. Males on creatine increased muscle strength (lat pull-down only) to a greater extent than females on creatine (p=0.005). Creatine enabled males to resistance train at a greater capacity over time compared to males on placebo (p=0.049) and females on creatine (p=0.012). Males on creatine (p=0.019) and females on placebo (p=0.014) decreased 3-MH compared to females on creatine. The addition of creatine to drop-set resistance training augments the gains in muscle mass from resistance training alone. Creatine is more effective in untrained aging males compared to untrained aging females. Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of creatine supplementation on oxidative stress profile of athletes

PubMed Central

2012-01-01

Background Creatine (Cr) supplementation has been widely used among athletes and physically active individuals. Secondary to its performance-enhancing ability, an increase in oxidative stress may occur, thus prompting concern about its use. The purpose of this study is to investigate the effects of Cr monohydrate supplementation and resistance training on muscle strength and oxidative stress profile in healthy athletes. Methods A randomized, double-blind, placebo-controlled method was used to assess twenty-six male elite Brazilian handball players divided into 3 groups: Cr monohydrate supplemented group (GC, N = 9), placebo group (GP, N = 9), no treatment group (COT, N = 8) for 32 days. All subjects underwent a resistance training program. Blood samples were drawn on 0 and 32 days post Cr supplementation to analyze the oxidative stress markers, thiobarbituric acid reactive species (TBARS), total antioxidant status (TAS), and uric acid. Creatine phosphokinase, urea, and creatinine were also analyzed, as well. Fitness tests (1 repetition maximum - 1RM and muscle endurance) were performed on the bench press. Body weight and height, body fat percentage (by measuring skin folds) and upper muscular area were also evaluated. Statistical analysis was performed using ANOVA. Results Only GC group showed increase in 1RM (54 ± 9 vs. 63 ± 10 kg; p = 0.0356) and uric acid (4.6 ± 1.0 vs. 7.4 ± 1.6 mg/dl; p = 0.025), with a decrease in TAS (1.11 ± 0.34 vs. 0.60 ± 0.19 mmol/l; p = 0.001). No differences (pre- vs. post-training) in TBARS, creatine phosphokinase, urea, creatinine, body weight and height, body fat percentage, or upper muscular area were observed in any group. When compared to COT, GC group showed greater decrease in TAS (−0.51 ± 0.36 vs. -0.02 ± 0.50 mmol/l; p = 0.0268), higher increase in 1RM (8.30 ± 2.26 vs. 5.29 ± 2.36 kg; p = 0.0209) and uric acid (2.77 ± 1.70 vs. 1.00 ± 1.03 mg/dl; p = 0.0276). Conclusion We conclude that Cr monohydrate supplementation associated with a specific resistance program promoted a meaningful increase in muscle strength without inducing changes in body composition. The observed significant increase in uric acid and the decrease in TAS suggest that creatine supplementation, despite promoting acute effects on muscle strength improvement, might induce oxidative stress and decreases total antioxidant status of subjects. PMID:23259853

Benefits of Resistance Training with Blood Flow Restriction in Knee Osteoarthritis.

PubMed

Ferraz, Rodrigo Branco; Gualano, Bruno; Rodrigues, Reynaldo; Kurimori, Ceci Obara; Fuller, Ricardo; Lima, Fernanda Rodrigues; DE Sá-Pinto, Ana Lúcia; Roschel, Hamilton

2018-05-01

Evaluate the effects of a low-intensity resistance training (LI-RT) program associated with partial blood flow restriction on selected clinical outcomes in patients with knee osteoarthritis (OA). Forty-eight women with knee OA were randomized into one of the three groups: LI-RT (30% one repetition maximum [1-RM]) associated (blood flow restriction training [BFRT]) or not (LI-RT) with partial blood flow restriction, and high-intensity resistance training (HI-RT, 80% 1-RM). Patients underwent a 12-wk supervised training program and were assessed for lower-limb 1-RM, quadriceps cross-sectional area, functionality (timed-stands test and timed-up-and-go test), and disease-specific inventory (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]) before (PRE) and after (POST) the protocol. Similar within-group increases were observed in leg press (26% and 33%, all P < 0.0001), knee extension 1-RM (23% and 22%; all P < 0.0001) and cross-sectional area (7% and 8%; all P < 0.0001) in BFRT and HI-RT, respectively, and these were significantly greater (all P < 0.05) than those of LI-RT. The BFRT and HI-RT showed comparable improvements in timed-stands test (7% and 14%, respectively), with the latter showing greater increases than LI-RT. Timed-up-and-go test scores were not significantly changed within or between groups. WOMAC physical function was improved in BFRT and HI-RT (-49% and -42%, respectively; all P < 0.05), and WOMAC pain was improved in BFRT and LI-RT (-45% and -39%, respectively; all P < 0.05). Four patients (of 16) were excluded due to exercise-induced knee pain in HI-RT. Blood flow restriction training and HI-RT were similarly effective in increasing muscle strength, quadriceps muscle mass, and functionality in knee OA patients. Importantly, BFRT was also able to improve pain while inducing less joint stress, emerging as a feasible and effective therapeutic adjuvant in OA management.

Effects of coffee and caffeine anhydrous intake during creatine loading

PubMed Central

Trexler, Eric T.; Smith-Ryan, Abbie E.; Roelofs, Erica J.; Hirsch, Katie R.; Persky, Adam M.; Mock, Meredith G.

2015-01-01

The purpose of this study was to determine the effect of 5 d of creatine (CRE) loading alone or in combination with caffeine anhydrous (CAF) or coffee (COF) on upper and lower body strength and sprint performance. Physically active males (n=54; Mean ± SD; Age = 20.1 ± 2.1 yrs; Weight = 78.8 ± 8.8 kg) completed baseline testing, consisting of one-repetition maximum (1RM) and repetitions to fatigue (RTF) with 80% 1RM for bench press (BP) and leg press (LP), followed by a repeated sprint test of five, 10 s sprints separated by 60 s rest on a cycle ergometer to determine peak power (PP) and total power (TP). At least 72 hr later, subjects were randomly assigned to supplement with CRE (5 g creatine monohydrate, 4 times*d−1; n=14), CRE+CAF (CRE + 300 mg*d−1 of CAF; n=13), CRE+COF (CRE + 8.9 g COF, yielding 303 mg caffeine; n=13), or placebo (PLA; n=14) for 5 d. Serum creatinine (CRN) was measured prior to and following supplementation and on day six, participants repeated pre-testing procedures. Strength measures were improved in all groups (p<0.05), with no significant time × treatment interactions. No significant interaction or main effects were observed for PP. For TP, a time × sprint interaction was observed (p<0.05), with no significant interactions between treatment groups. A time × treatment interaction was observed for serum CRN values (p<0.05) that showed increases in all groups except PLA. Four subjects reported mild gastrointestinal discomfort with CRE+CAF, with no side effects reported in other groups. These findings suggest that neither CRE alone, nor in combination with CAF or COF, significantly affected performance compared to PLA. PMID:26439785

Resistance training intensity and volume affect changes in rate of force development in resistance-trained men.

PubMed

Mangine, Gerald T; Hoffman, Jay R; Wang, Ran; Gonzalez, Adam M; Townsend, Jeremy R; Wells, Adam J; Jajtner, Adam R; Beyer, Kyle S; Boone, Carleigh H; Miramonti, Amelia A; LaMonica, Michael B; Fukuda, David H; Ratamess, Nicholas A; Stout, Jeffrey R

2016-12-01

To compare the effects of two different resistance training programs, high intensity (INT) and high volume (VOL), on changes in isometric force (FRC), rate of force development (RFD), and barbell velocity during dynamic strength testing. Twenty-nine resistance-trained men were randomly assigned to either the INT (n = 15, 3-5 RM, 3-min rest interval) or VOL (n = 14, 10-12 RM, 1-min rest interval) training group for 8 weeks. All participants completed a 2-week preparatory phase prior to randomization. Measures of barbell velocity, FRC, and RFD were performed before (PRE) and following (POST) the 8-week training program. Barbell velocity was determined during one-repetition maximum (1RM) testing of the squat (SQ) and bench press (BP) exercises. The isometric mid-thigh pull was used to assess FRC and RFD at specific time bands ranging from 0 to 30, 50, 90, 100, 150, 200, and 250 ms. Analysis of covariance revealed significant (p < 0.05) group differences in peak FRC, FRC at 30-200 ms, and RFD at 50-90 ms. Significant (p < 0.05) changes in INT but not VOL in peak FRC (INT: 9.2 ± 13.8 %; VOL: -4.3 ± 10.2 %), FRC at 30-200 ms (INT: 12.5-15.8 %; VOL: -1.0 to -4.3 %), and RFD at 50 ms (INT: 78.0 ± 163 %; VOL: -4.1 ± 49.6 %) were observed. A trend (p = 0.052) was observed for RFD at 90 ms (INT: 58.5 ± 115 %; VOL: -3.5 ± 40.1 %). No group differences were observed for the observed changes in barbell velocity. Results indicate that INT is more advantageous than VOL for improving FRC and RFD, while changes in barbell velocity during dynamic strength testing are similarly improved by both protocols in resistance-trained men.

The Effect of Rest Interval Length on Repetition Consistency and Perceived Exertion During Near Maximal Loaded Bench Press Sets.

PubMed

Scudese, Estevão; Willardson, Jeffrey M; Simão, Roberto; Senna, Gilmar; de Salles, Belmiro F; Miranda, Humberto

2015-11-01

The purpose of this study was to compare different rest intervals between sets on repetition consistency and ratings of perceived exertion (RPE) during consecutive bench press sets with an absolute 3RM (3 repetition maximum) load. Sixteen trained men (23.75 ± 4.21 years; 74.63 ± 5.36 kg; 175 ± 4.64 cm; bench press relative strength: 1.44 ± 0.19 kg/kg of body mass) attended 4 randomly ordered sessions during which 5 consecutive sets of the bench press were performed with an absolute 3RM load and 1, 2, 3, or 5 minutes of rest interval between sets. The results indicated that significantly greater bench press repetitions were completed with 2, 3, and 5 minutes vs. 1-minute rest between sets (p ≤ 0.05); no significant differences were noted between the 2, 3, and 5 minutes rest conditions. For the 1-minute rest condition, performance reductions (relative to the first set) were observed commencing with the second set; whereas for the other conditions (2, 3, and 5 minutes rest), performance reductions were not evident until the third and fourth sets. The RPE values before each of the successive sets were significantly greater, commencing with the second set for the 1-minute vs. the 3 and 5 minutes rest conditions. Significant increases were also evident in RPE immediately after each set between the 1 and 5 minutes rest conditions from the second through fifth sets. These findings indicate that when utilizing an absolute 3RM load for the bench press, practitioners may prescribe a time-efficient minimum of 2 minutes rest between sets without significant impairments in repetition performance. However, lower perceived exertion levels may necessitate prescription of a minimum of 3 minutes rest between sets.

Increasing arsenic sorption on red mud by phosphogypsum addition.

PubMed

Lopes, G; Guilherme, L R G; Costa, E T S; Curi, N; Penha, H G V

2013-11-15

Mining by-products have been tested as adsorbents for arsenic in order to reduce As bioavailability. This study evaluated a red mud (RM) treated with or without phosphogypsum (G) in order to improve its As retention. Red mud and G samples and their mixtures were chemically and mineralogically characterized to gather information concerning their composition, which is key for a better understanding of the adsorbent properties. Phosphogypsum was added to RM in the following proportions: 0, 1, 2, 5, 10, and 25% by weight. These mixtures were subjected to As adsorption and desorption and tested for their maximum adsorption capacity of As (AsMAC). Arsenic adsorption increased upon increasing the proportion of G added to RM. The AsMAC at pure RM reached 909 mg kg(-1), whereas the 75%-RM+25%-G mixture sorbed up to 3333 mg kg(-1) of As, i.e., a 3.5-fold increase in AsMAC. Using G in mixtures with RM increases the efficiency of As adsorption due to the presence of Ca(2+), which alters the charge balance of the adsorbent, leading to the formation of ternary complexes. Addition of G to RM is thus a promising technique to improve As retention, while providing additional value to both by-products, G and RM. Copyright © 2012 Elsevier B.V. All rights reserved.

Effect of different pushing speeds on bench press.

PubMed

Padulo, J; Mignogna, P; Mignardi, S; Tonni, F; D'Ottavio, S

2012-05-01

The purpose of this study was to investigate the effect on muscular strength after a 3-week training with the bench-press at a fixed pushing of 80-100% maximal speed (FPS) and self-selected pushing speed (SPS). 20 resistance-trained subjects were divided at random in 2 groups differing only regarding the pushing speed: in the FPS group (n=10) it was equal to 80-100% of the maximal speed while in the SPS group (n=10) the pushing speed was self-selected. Both groups were trained twice a week for 3 weeks with a load equal to 85% of 1RM and monitored with the encoder. Before and after the training we measured pushing speed and maximum load. Significant differences between and within the 2 groups were pointed out using a 2-way ANOVA for repeated measures. After 3 weeks a significant improvement was shown especially in the FPS group: the maximum load improved by 10.20% and the maximal speed by 2.22%, while in the SPS group the effect was <1%. This study shows that a high velocity training is required to increase the muscle strength further in subjects with a long training experience and this is possible by measuring the individual performance speed for each load. © Georg Thieme Verlag KG Stuttgart · New York.

Effects of Coffee and Caffeine Anhydrous Intake During Creatine Loading.

PubMed

Trexler, Eric T; Smith-Ryan, Abbie E; Roelofs, Erica J; Hirsch, Katie R; Persky, Adam M; Mock, Meredith G

2016-05-01

The purpose of this study was to determine the effect of 5 days of creatine (CRE) loading alone or in combination with caffeine anhydrous (CAF) or coffee (COF) on upper-body and lower-body strength and sprint performance. Physically active males (n = 54; mean ± SD; age = 20.1 ± 2.1 years; weight = 78.8 ± 8.8 kg) completed baseline testing, consisting of 1 repetition maximum (1RM) and repetitions to fatigue with 80% 1RM for bench press and leg press, followed by a repeated sprint test of five, 10-second sprints separated by 60-second rest on a cycle ergometer to determine peak power (PP) and total power (TP). At least 72 hours later, subjects were randomly assigned to supplement with CRE (5 g of CRE monohydrate, 4 times per day; n = 14), CRE + CAF (CRE +300 mg·d of CAF; n = 13), CRE + COF (CRE +8.9 g of COF, yielding 303 mg of CAF; n = 13), or placebo (PLA; n = 14) for 5 days. Serum creatinine (CRN) was measured before and after supplementation, and on day 6, participants repeated pretesting procedures. Strength measures were improved in all groups (p ≤ 0.05), with no significant time × treatment interactions. No significant interaction or main effects were observed for PP. For TP, a time × sprint interaction was observed (p ≤ 0.05), with no significant interactions among treatment groups. A time × treatment interaction was observed for serum CRN values (p ≤ 0.05) that showed increases in all groups except PLA. Four subjects reported mild gastrointestinal discomfort with CRE + CAF, with no side effects reported in other groups. These findings suggest that neither CRE alone nor in combination with CAF or COF significantly affected performance compared with PLA.

Validation and Reliability of a Novel Test of Upper Body Isometric Strength.

PubMed

Bellar, David; Marcus, Lena; Judge, Lawrence W

2015-09-29

The purpose of the present investigation was to examine the association of a novel test of upper body isometric strength against a 1RM bench press measurement. Forty college age adults (n = 20 female, n = 20 male; age 22.8 ± 2.8 years; body height 171.6 ± 10.8 cm; body mass 73.5 ± 16.3 kg; body fat 23.1 ± 5.4%) volunteered for the present investigation. The participants reported to the lab on three occasions. The first visit included anthropometric measurements and familiarization with both the upper body isometric test and bench press exercise. The final visits were conducted in a randomized order, with one being a 1RM assessment on the bench press and the other consisting of three trials of the upper body isometric assessment. For the isometric test, participants were positioned in a "push-up" style position while tethered (stainless steel chain) to a load cell (high frequency) anchored to the ground. The peak isometric force was consistent across all three trials (ICC = 0.98) suggesting good reliability. Multiple regression analysis was completed with the predictors: peak isometric force, gender, against the outcome variable 1RM bench press. The analysis resulted in a significant model (r2 = 0.861, p≤0.001) with all predictor variables attaining significance in the model (p<0.05). Isometric peak strength had the greatest effect on the model (Beta = 5.19, p≤0.001). Results from this study suggest that the described isometric upper body strength assessment is likely a valid and reliable tool to determine strength. Further research is warranted to gather a larger pool of data in regard to this assessment.

Validation and Reliability of a Novel Test of Upper Body Isometric Strength

PubMed Central

Bellar, David; Marcus, Lena; Judge, Lawrence W.

2015-01-01

The purpose of the present investigation was to examine the association of a novel test of upper body isometric strength against a 1RM bench press measurement. Forty college age adults (n = 20 female, n = 20 male; age 22.8 ± 2.8 years; body height 171.6 ± 10.8 cm; body mass 73.5 ± 16.3 kg; body fat 23.1 ± 5.4%) volunteered for the present investigation. The participants reported to the lab on three occasions. The first visit included anthropometric measurements and familiarization with both the upper body isometric test and bench press exercise. The final visits were conducted in a randomized order, with one being a 1RM assessment on the bench press and the other consisting of three trials of the upper body isometric assessment. For the isometric test, participants were positioned in a “push-up” style position while tethered (stainless steel chain) to a load cell (high frequency) anchored to the ground. The peak isometric force was consistent across all three trials (ICC = 0.98) suggesting good reliability. Multiple regression analysis was completed with the predictors: peak isometric force, gender, against the outcome variable 1RM bench press. The analysis resulted in a significant model (r2 = 0.861, p≤0.001) with all predictor variables attaining significance in the model (p<0.05). Isometric peak strength had the greatest effect on the model (Beta = 5.19, p≤0.001). Results from this study suggest that the described isometric upper body strength assessment is likely a valid and reliable tool to determine strength. Further research is warranted to gather a larger pool of data in regard to this assessment. PMID:26557203

Effect of strength training with blood flow restriction on muscle power and submaximal strength in eumenorrheic women.

PubMed

Gil, Ana L S; Neto, Gabriel R; Sousa, Maria S C; Dias, Ingrid; Vianna, Jeferson; Nunes, Rodolfo A M; Novaes, Jefferson S

2017-03-01

Blood flow restriction (BFR) training stimulates muscle size and strength by increasing muscle activation, accumulation of metabolites and muscle swelling. This method has been used in different populations, but no studies have evaluated the effects of training on muscle power and submaximal strength (SS) in accounted for the menstrual cycle. The aim of this study was to analyse the effect of strength training (ST) with BFR on the muscle power and SS of upper and lower limbs in eumenorrheic women. Forty untrained women (18-40 years) were divided randomly and proportionally into four groups: (i) high-intensity ST at 80% of 1RM (HI), (ii) low-intensity ST at 20% of 1RM combined with partial blood flow restriction (LI + BFR), (iii) low-intensity ST at 20% of 1RM (LI) and d) control group (CG). Each training group performed eight training sessions. Tests with a medicine ball (MB), horizontal jump (HJ), vertical jump (VJ), biceps curls (BC) and knee extension (KE) were performed during the 1st day follicular phase (FP), 14th day (ovulatory phase) and 26-28th days (luteal phase) of the menstrual cycle. There was no significant difference among groups in terms of the MB, HJ, VJ or BC results at any time point (P>0·05). SS in the KE exercise was significantly greater in the LI + BFR group compared to the CG group (P = 0·014) during the LP. Therefore, ST with BFR does not appear to improve the power of upper and lower limbs and may be an alternative to improve the SS of lower limbs of eumenorrheic women. © 2015 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Effects of intra-session exercise sequence during water-based concurrent training.

PubMed

Pinto, S S; Cadore, E L; Alberton, C L; Zaffari, P; Bagatini, N C; Baroni, B M; Radaelli, R; Lanferdini, F J; Colado, J C; Pinto, R S; Vaz, M A; Bottaro, M; Kruel, L F M

2014-01-01

The aim was to investigate the effects of the intra-session exercise order during water-based concurrent training on the neuromuscular adaptations in young women. 26 women (25.1±2.9 years) were placed into 2 groups: resistance prior to (RA) or after (AR) aerobic training. Subjects performed resistance (sets at maximal effort) and aerobic training (exercises at heart rate corresponding to the second ventilatory threshold) twice a week over 12 weeks, performing both exercise types in the same training session. Upper (elbow flexion) and lower-body (knee extension) one-repetition maximum test (1RM) and peak torque (PT) were evaluated. The muscle thickness (MT) of upper (sum of MT of biceps brachii and brachialis) and lower-body (sum of MT of vastus lateralis, vastus medialis, vastus intermedius, and rectus femoris) was determined by ultrasonography. Moreover, the maximal electromyographic activity (EMG) of upper (biceps brachii) and lower-body (sum of EMG of vastus lateralis and rectus femoris) was measured. Both RA and AR groups increased the upper and lower-body 1RM and PT, while the lower-body 1RM increases observed in the RA was greater than AR (43.58±14.00 vs. 27.01±18.05%). RA and AR showed MT increases in all muscles evaluated, while the lower-body MT increases observed in the RA were also greater than AR (10.24±3.11 vs. 5.76±1.88%). There were increases in the maximal EMG of upper and lower-body in both RA and AR, with no differences between groups. Performing resistance prior to aerobic exercise during water-based concurrent training seems to optimize the lower-body strength and hypertrophy. © Georg Thieme Verlag KG Stuttgart · New York.

Nonlinear Analysis of an Unstable Bench Press Bar Path and Muscle Activation.

PubMed

Lawrence, Michael A; Leib, Daniel J; Ostrowski, Stephanie J; Carlson, Lara A

2017-05-01

Lawrence, MA, Leib, DJ, Ostrowski, SJ, and Carlson, LA. Nonlinear analysis of an unstable bench press bar path and muscle activation. J Strength Cond Res 31(5): 1206-1211, 2017-Unstable resistance exercises are typically performed to improve the ability of stabilizing muscles to maintain joint integrity under a load. The purpose of this study was to examine the effects of an unstable load (as provided by a flexible barbell and a load suspended by elastic bands) on the bar path, the primary musculature, and stabilizing musculature while bench pressing using nonlinear analyses. Fifteen resistance-trained men (age 24.2 ± 2.7 years, mass 84.1 ± 12.0 kg, height 1.77 ± 0.05 m, 9.9 ± 3.4 years of lifting experience, and bench press 1 repetition maximum (RM) 107.5 ± 25.9 kg) volunteered for this study. Subjects pressed 2 sets of 5 repetitions in both stable (total load 75% 1RM) and unstable (total load 60% 1RM) conditions using a standard barbell and a flexible Earthquake bar, respectively. Surface electromyography was used to detect muscle activity of primary movers (pectoralis major, anterior deltoid, and triceps) and bar stabilizing musculature (latissimus dorsi, middle and posterior deltoid, biceps brachii, and upper trapezius). During the unstable condition, the bar moved in more ways and was less predictable in the mediolateral and anteroposterior directions. However, the muscle activation patterns of all muscles were more constrained with the unstable barbell. These findings suggest that the unstable condition was more challenging to control, but subjects controlled the instability by contracting their muscles in a more stable pattern or "staying tight" throughout the exercise.

Benefits of combined aerobic/resistance/inspiratory training in patients with chronic heart failure. A complete exercise model? A prospective randomised study.

PubMed

Laoutaris, Ioannis D; Adamopoulos, Stamatis; Manginas, Athanassios; Panagiotakos, Demosthenes B; Kallistratos, Manolis S; Doulaptsis, Costas; Kouloubinis, Alexandros; Voudris, Vasilis; Pavlides, Gregory; Cokkinos, Dennis V; Dritsas, Athanasios

2013-09-01

We hypothesised that combined aerobic training (AT) with resistance training (RT) and inspiratory muscle training (IMT) could result in additional benefits over AT alone in patients with chronic heart failure (CHF). Twenty-seven patients, age 58 ± 9 years, NYHA II/III and LVEF 29 ± 7% were randomly assigned to a 12-week AT (n=14) or a combined AT/RT/IMT (ARIS) (n=13) exercise program. AT consisted of bike exercise at 70-80% of max heart rate. ARIS training consisted of AT with RT of the quadriceps at 50% of 1 repetition maximum (1RM) and upper limb exercises using dumbbells of 1-2 kg as well as IMT at 60% of sustained maximal inspiratory pressure (SPI(max)). At baseline and after intervention patients underwent cardiopulmonary exercise testing, echocardiography, evaluation of dyspnea, muscle function and quality of life (QoL) scores. The ARIS program as compared to AT alone, resulted in additional improvement in quadriceps muscle strength (1RM, p=0.005) and endurance (50%1 RM × number of max repetitions, p=0.01), SPI(max) (p<0.001), exercise time (p=0.01), circulatory power (peak oxygen consumption × peak systolic blood pressure, p=0.05), dyspnea (p=0.03) and QoL (p=0.03). ARIS training was safe and resulted in incremental benefits in both peripheral and respiratory muscle weakness, cardiopulmonary function and QoL compared to that of AT. The present findings may add a new prospective to cardiac rehabilitation programs of heart failure patients whilst the clinical significance of these outcomes need to be addressed in larger randomised studies. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Semi-empirical scaling for ion–atom single charge exchange cross sections in the intermediate velocity regime

DOE PAGES

Friedman, B.; DuCharme, G.

2017-05-11

We present a semi-empirical scaling law for non-resonant ion–atom single charge exchange cross sections for collisions with velocities frommore » $${10}^{7}\\,{\\rm{t}}{\\rm{o}}\\,{10}^{9}\\,\\mathrm{cm}\\,{{\\rm{s}}}^{-1}$$ and ions with positive charge $$q\\lt 8$$. Non-resonant cross sections tend to have a velocity peak at collision velocities $$v\\lesssim 1\\ {\\rm{a}}{\\rm{u}}$$ with exponential decay around this peak. We construct a scaling formula for the location of this peak then choose a functional form for the cross section curve and scale it. The velocity at which the cross section peaks, v m, is proportional to the energy defect of the collision, $${\\rm{\\Delta }}E$$, which we predict with the decay approximation. The value of the cross section maximum is proportional to the charge state q, inversely proportional to the target ionization energy I T, and inversely proportional to v m. For the shape of the cross section curve, we use a function that decays exponentially asymptotically at high and low velocities. We scale this function with parameters $${v}_{{\\rm{m}}},{I}_{{\\rm{T}}},{Z}_{{\\rm{T}}},\\mathrm{and}\\ {Z}_{{\\rm{P}}}$$, where the $${Z}_{{\\rm{T}},{\\rm{P}}}$$ are the target and projectile atomic numbers. In conclusion, for the more than 100 cross section curves that we use to find the scaling rules, the scaling law predicts cross sections within a little over a factor of 2 on average.« less

Time course for arm and chest muscle thickness changes following bench press training

PubMed Central

Ogasawara, Riki; Thiebaud, Robert S.; Loenneke, Jeremy P.; Loftin, Mark

2012-01-01

The purpose of this study was to investigate the time course of hypertrophic adaptations in both the upper arm and trunk muscles following high-intensity bench press training. Seven previously untrained young men (aged 25 ± 3 years) performed free-weight bench press training 3 days (Monday, Wednesday and Friday) per week for 24 weeks. Training intensity and volume were set at 75% of one repetition maximum (1-RM) and 30 repetitions (3 sets of 10 repetitions, with 2−3 min of rest between sets), respectively. Muscle thickness (MTH) was measured using B-mode ultrasound at three sites: the biceps and triceps brachii and the pectoralis major. Measurements were taken a week prior to the start of training, before the training session on every Monday and 3 days after the final training session. Pairwise comparisons from baseline revealed that pectoralis major MTH significantly increased after week-1 (p = 0.002), triceps MTH increased after week-5 (p = 0.001) and 1-RM strength increased after week-3 (p = 0.001) while no changes were observed in the biceps MTH from baseline. Significant muscle hypertrophy was observed earlier in the chest compared to that of the triceps. Our results indicate that the time course of the muscle hypertrophic response differs between the upper arm and chest. PMID:24265879

Comparison of the effects of an eight-week push-up program using stable versus unstable surfaces.

PubMed

Chulvi-Medrano, Iván; Martínez-Ballester, Esteban; Masiá-Tortosa, Laura

2012-12-01

Recently, the trend among physical training and rehabilitation professionals is the use of resistance exercise on unstable equipment in order to increase the effort of the agonist and stabilizing muscles. It is unknown if performing exercises on unstable surfaces provides a greater training stimulus as compared to training on a stable training surface. Therefore, the purpose of this research was to compare the effect that push-up training on stable and unstable surfaces had on strength performance in healthy young men. Thirty subjects with experience in resistance training participated in push-up training two days per week for eight weeks on one of three different surfaces: the floor (Tp), the T-Bow® (TBp) or the BOSU® (Bp). Strength, as measured by one repetition maximum (1-RM) and muscle endurance, as measured by number of pushups performed did not improve significantly (p>0.05) for any of the intervention groups. The addition of unstable surfaces in push-up training does not provide greater improvement in muscular strength and endurance than push up training performed on a stable surface in young men. 3b.

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.

Inhibition of seedling survival under Rhododendron maximum (Ericaceae): could allelopathy be a cause?

PubMed

Nilsen, E T; Walker, J F; Miller, O K; Semones, S W; Lei, T T; Clinton, B D

1999-11-01

In the southern Appalachian mountains a subcanopy species, Rhododendron maximum, inhibits the establishment and survival of canopy tree seedlings. One of the mechanisms by which seedlings could be inhibited is an allelopathic effect of decomposing litter or leachate from the canopy of R. maximum (R.m.) on seed germination, root elongation, or mycorrhizal colonization. The potential for allelopathy by R.m. was tested with two bioassay species (lettuce and cress), with seeds from four native tree species, and with three ectomycorrhizal fungi. Inhibitory influences of throughfall, fresh litter, and decomposed litter (organic layer) from forest with R.m. (+R.m. sites) were compared to similar extractions made from forest without R.m. (-R.m. sites). Throughfall and leachates of the organic layer from both +R.m. and -R.m. sites stimulated germination of the bioassay species above that of the distilled water control, to a similar extent. There was an inhibitory effect of leachates of litter from +R.m. sites on seed germination and root elongation rate of both bioassay species compared with that of litter from -R.m. sites. Native tree seed stratified in forest floor material from both forest types had a slightly higher seed germination rate compared with the control. A 2-yr study of seed germination and seedling mortality of two tree species, Quercus rubra and Prunus serotina, in field plots showed no significant influence of litter or organic layer from either forest type. Incorporating R.m. leaf material into the growth medium in vitro depressed growth of one ectomycorrhizal species but did not affect two other species. Leaf material from other deciduous tree species depressed ectomycorrhizal growth to a similar or greater extent as leaf material from R.m. In conclusion, R.m. litter can have an allelopathic effect on seed germination and root elongation of bioassay species as well as some ectomycorrhizal species. However, this allelopathic affect is not manifest in field sites and is not likely to be an important cause for the inhibition of seedling survival within thickets of R.m.

Free-Weight Augmentation With Elastic Bands Improves Bench Press Kinematics in Professional Rugby Players.

PubMed

García-López, David; Hernández-Sánchez, Sonsoles; Martín, Esperanza; Marín, Pedro J; Zarzosa, Fernando; Herrero, Azael J

2016-09-01

García-López, D, Hernández-Sánchez, S, Martín, E, Marín, PJ, Zarzosa, F, and Herrero, AJ. Free-weight augmentation with elastic bands improves bench press kinematics in professional rugby players. J Strength Cond Res 30(9): 2493-2499, 2016-This study aimed to investigate the effects of combining elastic bands to free weight resistance (EB + FWR) on the acceleration-deceleration and velocity profiles of the bench press in professional rugby players and recreationally trained subjects. Sixteen male subjects (8 rugby players and 8 recreationally trained subjects) were randomly assigned to complete 2 experimental conditions in a crossover fashion: EB + FWR and FWR. In both conditions, subjects performed 1 bench press set to volitional exhaustion with a load equivalent to the 85% of 1 repetition maximum (1RM). In the EB + FWR condition, the contribution of elastic resistance was approximately 20% of the selected load (85% 1RM). Results indicate that EB + FWR condition increased significantly the range of concentric movement in which the barbell is accelerated. This increase was significantly higher in rugby players (35%) in comparison with recreationally trained subjects (13%). Maximal velocity was also increased in EB + FWR (17%), when compared with FWR condition. These results suggest that when combined with variable resistance (i.e., EB), the external resistance seems to be more evenly distributed over the full range of motion, decreasing the need for dramatic deceleration at the end of the concentric phase. The present data also indicate that the kinematic benefits of an EB + FWR approach seems to be more prominent in athletes from modalities in which high level of strength and power are required (i.e., rugby players).

Tear Strength and Tensile Strength of Model Filled Elastomers.

DTIC Science & Technology

1980-04-10

X4PWQ Approved for public release; distribution unlimited 17. DISTRIUUTIO" STATEMENT (of Cho abm ,.. uo lm 8016401 Stock ". If 1eral b Rd~M) 0S...5011 Eisenhower Ave. Rm 8N4-2 Alexandria, VA 22333Naval Sea Sytems Command 1 Washington, D.C. 20362 Att : Mr. R. Beauregard SEA 64E Commander 1Naval

Trunk muscle activation during dynamic weight-training exercises and isometric instability activities.

PubMed

Hamlyn, Nicolle; Behm, David G; Young, Warren B

2007-11-01

The purpose of this study was to examine the extent of activation in various trunk muscles during dynamic weight-training and isometric instability exercises. Sixteen subjects performed squats and deadlifts with 80% 1 repetition maximum (1RM), as well as with body weight as resistance and 2 unstable calisthenic-type exercises (superman and sidebridge). Electromyographic (EMG) activity was measured from the lower abdominals (LA), external obliques (EO), upper lumbar erector spinae (ULES), and lumbar-sacral erector spinae (LSES) muscle groups. Results indicated that the LSES EMG activity during the 80% 1RM squat significantly exceeded 80% 1RM deadlift LSES EMG activity by 34.5%. The LSES EMG activity of the 80% 1RM squat also exceeded the body weight squat, deadlift, superman, and sidebridge by 56, 56.6, 65.5, and 53.1%, respectively. The 80% 1RM deadlift ULES EMG activity significantly exceeded the 80% 1RM squat exercise by 12.9%. In addition, the 80% 1RM deadlift ULES EMG activity also exceeded the body weight squat, deadlift, superman, and sidebridge exercises by 66.7, 65.5, 69.3, and 68.6%, respectively. There were no significant changes in EO or LA activity. Therefore, the augmented activity of the LSES and ULES during 80% 1RM squat and deadlift resistance exercises exceeded the activation levels achieved with the same exercises performed with body weight and selected instability exercises. Individuals performing upright, resisted, dynamic exercises can achieve high trunk muscle activation and thus may not need to add instability device exercises to augment core stability training.

Effects of Pre-exhaustion on the Patterns of Muscular Activity in the Flat Bench Press.

PubMed

Gołaś, Artur; Maszczyk, Adam; Pietraszewski, Przemyslaw; Stastny, Petr; Tufano, James J; Zając, Adam

2017-07-01

Gołaś, A, Maszczyk, A, Pietraszewski, P, Stastny, P, Tufano, JJ, and Zając, A. Effects of pre-exhaustion on the patterns of muscular activity in the flat bench press. J Strength Cond Res 31(7): 1919-1924, 2017-Pre-exhaustion (PE) has been applied in resistance training (RT) to manipulate the order of performing 2 resistance exercises, a single-joint exercise to momentary exhaustion, followed by a multi-joint movement that includes the same muscle group. This method ensures greater recruitment of muscles or muscle groups in the multi-joint exercise to further increase muscle strength and overcome strength plateaus. The purpose of the present study was to investigate muscle activity by electromyography during high-intensity (95% of 1 repetition maximum [RM]) bench press (BP), before and after PE of the pectoralis major (PM), anterior deltoid (AD), and triceps brachii (TB) muscles to determine the effects of PE of the prime movers. Eight healthy athletes, experienced in RT, participated in the study. There were 4 sessions in the experiment. Session 1 was aimed at determination of 1RM during a flat BP. Sessions 2, 3, and 4 consisted of performing a BP after PE of the muscles studied by the incline dumbbell fly, front deltoid raise, and lying triceps extension exercise. Peak concentric TB activation after TB PE (mean ± SD, 147.76 ± 18.6%) was significantly greater by analysis of variance (η = 0.82, F = 5.45, p = 0.004) compared with peak TB activation (114.77 ± 19.4%) before TB PE. The statistical analysis for PM and AD did not show any significant differences. Coaches should not expect the usefulness of PE protocol to elicit higher PM or AD activity or fatigue, but they can use it to increase TB activity before high-intensity BP exercise.

Multimodal high-intensity interval training increases muscle function and metabolic performance in females.

PubMed

Buckley, Stephanie; Knapp, Kelly; Lackie, Amy; Lewry, Colin; Horvey, Karla; Benko, Chad; Trinh, Jason; Butcher, Scotty

2015-11-01

High-intensity interval training (HIIT) is a time-efficient method of improving aerobic and anaerobic power and capacity. In most individuals, however, HIIT using modalities such as cycling, running, and rowing does not typically result in increased muscle strength, power, or endurance. The purpose of this study is to compare the physiological outcomes of traditional HIIT using rowing (Row-HIIT) with a novel multimodal HIIT (MM-HIIT) circuit incorporating multiple modalities, including strength exercises, within an interval. Twenty-eight recreationally active women (age 24.7 ± 5.4 years) completed 6 weeks of either Row-HIIT or MM-HIIT and were tested on multiple fitness parameters. MM-HIIT and Row-HIIT resulted in similar improvements (p < 0.05 for post hoc pre- vs. post-training increases for each group) in maximal aerobic power (7% vs. 5%), anaerobic threshold (13% vs. 12%), respiratory compensation threshold (7% vs. 5%), anaerobic power (15% vs. 12%), and anaerobic capacity (18% vs. 14%). The MM-HIIT group had significant (p < 0.01 for all) increases in squat (39%), press (27%), and deadlift (18%) strength, broad jump distance (6%), and squat endurance (280%), whereas the Row-HIIT group had no increase in any muscle performance variable (p values 0.33-0.90). Post-training, 1-repetition maximum (1RM) squat (64.2 ± 13.6 vs. 45.8 ± 16.2 kg, p = 0.02), 1RM press (33.2 ± 3.8 vs. 26.0 ± 9.6 kg, p = 0.01), and squat endurance (23.9 ± 12.3 vs. 10.2 ± 5.6 reps, p < 0.01) were greater in the MM-HIIT group than in the Row-HIIT group. MM-HIIT resulted in similar aerobic and anaerobic adaptations but greater muscle performance increases than Row-HIIT in recreationally active women.

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.

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.

Velocity Loss as a Variable for Monitoring Resistance Exercise.

PubMed

González-Badillo, Juan José; Yañez-García, Juan Manuel; Mora-Custodio, Ricardo; Rodríguez-Rosell, David

2017-03-01

This study aimed to analyze: 1) the pattern of repetition velocity decline during a single set to failure against different submaximal loads (50-85% 1RM) in the bench press exercise; and 2) the reliability of the percentage of performed repetitions, with respect to the maximum possible number that can be completed, when different magnitudes of velocity loss have been reached within each set. Twenty-two men performed 8 tests of maximum number of repetitions (MNR) against loads of 50-55-60-65-70-75-80-85% 1RM, in random order, every 6-7 days. Another 28 men performed 2 separate MNR tests against 60% 1RM. A very close relationship was found between the relative loss of velocity in a set and the percentage of performed repetitions. This relationship was very similar for all loads, but particularly for 50-70% 1RM, even though the number of repetitions completed at each load was significantly different. Moreover, the percentage of performed repetitions for a given velocity loss showed a high absolute reliability. Equations to predict the percentage of performed repetitions from relative velocity loss are provided. By monitoring repetition velocity and using these equations, one can estimate, with considerable precision, how many repetitions are left in reserve in a bench press exercise set. © Georg Thieme Verlag KG Stuttgart · New York.

Using Growth and Arrest of Richtmyer-Meshkov Instabilities and Lagrangian Simulations to Study High-Rate Material Strength

NASA Astrophysics Data System (ADS)

Prime, Michael; Vaughan, Diane; Preston, Dean; Oro, David; Buttler, William

2013-06-01

Rayleigh-Taylor instabilities have been widely used to study the deviatoric (flow) strength of solids at high strain rates. More recently, experiments applying a supported shock through mating surfaces (Atwood number = 1) with geometrical perturbations have been proposed for studying strength at strain rates up to 107/sec using Richtmyer-Meshkov (RM) instabilities. Buttler et al. [J. Fluid Mech., 2012] recently reported experimental results for RM instability growth but with an unsupported shock applied by high explosives and the geometrical perturbations on the opposite free surface (Atwood number = -1). This novel configuration allowed detailed experimental observation of the instability growth and arrest. We present results and detailed interpretation from numerical simulations of the Buttler experiments on copper. Highly-resolved, two-dimensional simulations were performed using a Lagrangian hydrocode and the Preston-Tonks-Wallace (PTW) strength model. The model predictions show good agreement with the data in spite of the PTW model being calibrated on lower strain rate data. The numerical simulations are used to 1) examine various assumptions previously made in an analytical model, 2) to estimate the sensitivity of such experiments to material strength and 3) to explore the possibility of extracting meaningful strength information in the face of complicated spatial and temporal variations of stress, pressure, and temperature during the experiments.

Effects of Modified Pyramid System on Muscular Strength and Hypertrophy in Older Women.

PubMed

Dos Santos, Leandro; Ribeiro, Alex S; Cavalcante, Edilaine F; Nabuco, Hellen C; Antunes, Melissa; Schoenfeld, Brad J; Cyrino, Edilson S

2018-06-26

This study aimed to analyze the effects of a pyramid system performed with two repetition zones on muscular strength and skeletal muscle mass (SMM) in older women. Thirty-nine physically independent older women (67.8±5.4 years) were randomly assigned into one of two of groups that performed an 8-week resistance training program in an ascending pyramid fashion. Both groups performed 3 sets: a narrow repetition zone (NPR, n=20) with 12/10/8 repetitions, and a wide repetition zone (WPR, n=19) with 15/10/5 repetitions. The program consisted of 8 whole-body exercises, performed 3 times a week. Dual-energy X-ray absorptiometry was used to measure SMM, and muscular strength was evaluated by one-repetition maximum (1RM). Both groups increased (P<0.05) SMM (NPR=+ 4.7%, effect size=+ 0.34; WPR=+ 8.4%, effect size=+ 0.77), and total strength (NPR=+ 11.3%, effect size=+ 0.80; WPR=+ 13.8%, effect size=0.84), without statistical differences between them. Results suggest that both zones of repetitions in a pyramid system are effective strategies to improve muscular strength and muscle growth in older women. © Georg Thieme Verlag KG Stuttgart · New York.

Dietary intake habits and controlled training on body composition and strength in elite female volleyball players during the season.

PubMed

Mielgo-Ayuso, Juan; Zourdos, Michael C; Calleja-González, Julio; Urdampilleta, Aritz; Ostojic, Sergej M

2015-08-01

The purpose of this study was to assess dietary intake of elite female volleyball players (EFVPs, n = 22) during the first 11 weeks of the competitive season. Further, we compared findings for total energy intake and specific macronutrient distribution with the established recommendations for high-intensity athletes. Subjects also engaged in periodized training and we assessed changes in body composition (BC) and strength. Twenty-two EFVPs had dietary intake (7-day dietary recall and food-frequency questionnaire), BC (body mass index (BMI), body fat percentage, fat mass, muscle mass), and 1-repetition maximum (1RM) strength (bench press, military press, back squat, power clean, clean and jerk, pull-over) assessed at baseline (T0, before preseason) and 11 weeks later (T11). Athletes consumed less total kilocalories and carbohydrates (CHO) compared with established recommendations (total kilocalories: 40.7 ± 5.2 kcal/(kg · day)(-1) vs. 50-80 kcal/(kg · day)(-1); CHO: 4.3 ± 0.6 g/(kg · day)(-1) vs. 5-8 g/(kg · day)(-1)). Further, subjects consumed greater protein (2.1 ± 0.4 g/(kg · day)(-1)) compared with recommendations (1.6-1.8 g/(kg · day)(-1)) and greater fat (36.1 ± 4.6% of total kilocalories) than recommendations (20%-35% of total kilocalories). There were improvements (p < 0.05) in BC from T0-T11 (body fat percentage: 17.9% ± 4.2%-16.8% ± 3.6%, -4.7% ± 7.4%; fat mass: 12.7 ± 4.2-11.9 ± 3.8 kg, -4.0% ± 9.2%; muscle mass: 42.8% ± 3.4%-43.3% ± 3.0%, +1.3 ± 3.1%) and 1RM strength (bench press: 39.1 ± 4.5-43.4 ± 4.9 kg; +11.4% ± 9.3%; clean and jerk: 29.7 ± 6.3-34 ± 5.8 kg; +17.7% ± 23.8%); however, there was no change (p > 0.05) in BMI or military press and pull-over. Back squat (p = 0.054; +33.0% ± 83.7%) and power clean (p = 0.056; +26.2% ± 49.0%) increases approached significance. Our findings indicate that EFVPs improved BC and strength despite a dietary intake different from recommendations. This is possibly due to different substrate utilization during exercise in females versus males, thus new recommendations should be considered for high-intensity athletes, which are sex-specific.

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.

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.

Chronic effect of static stretching on strength performance and basal serum IGF-1 levels.

PubMed

Borges Bastos, Carmen L; Miranda, Humberto; Vale, Rodrigo Gomes de Souza; Portal, Maria de Nazaré; Gomes, M Thiago; Novaes, Jefferson da Silva; Winchester, Jason B

2013-09-01

Improving the process of how physical performance is enhanced is one of the main topics evaluated by physiologists. This process often involves athletes and nonathletic populations. The purpose of this study was to assess the chronic response to 10 weeks of static stretching exercises carried out before and during a strength training program for 8 exercises on an 8 repetition maximum (8RM) test performance, and basal serum insulinlike growth factor (IGF-1) levels. Thirty recreationally trained volunteers were randomly assigned to 1 of 3 training groups: (a) SBST (performed a warm-up with a static stretching protocol before each strength training session); (b) SDST (before each training set, a static stretching exercise was performed); and (c) OST (entire session was performed without any type of stretching exercise). Strength and IGF-1 levels were collected at the beginning (pretest) and end (posttest) of the entire experimental procedure. All the exercises showed a significant increase in muscle strength for the OST group. However, the results revealed a significant increase in the muscle strength for only a few exercises in the SBST (LP, LE) and SDST (LP) experimental conditions. Significant statistical differences were found between SBST and SDST for all the exercises in the OST experimental condition. Furthermore, the IGF-1 expression showed no significant differences in the intragroup analysis. However, the OST group showed higher values (p < 0.05) in the posttest when compared with those of the other groups (increased significantly only in the OST experimental condition). It has been concluded that, although all the groups showed an increase in muscular strength, the strength training performed without any type of stretching exercise, regardless of whether the stretching is performed before or during the lifting session, can more effectively increase muscle strength and basal serum IGF-1 levels. It was concluded that strength training, with or without the use of stretching exercises, increased muscular strength in the studied groups, and can induce an increase in IGF-1 levels.

Contribution of vertical strength and power to sprint performance in young male athletes.

PubMed

Meylan, C M P; Cronin, J; Oliver, J L; Hopkins, W G; Pinder, S

2014-08-01

The purpose of this study was to assess the possible contribution of 1RM leg-press strength and jump peak power to 20-m sprint time in young athletes in three maturity groups based on age relative to predicted age of peak height velocity (PHV): Pre (- 2.5 to -1.0 years; n=25), Mid (- 1.0 to 0.5 years; n=26) and Post (0.5 to 2.0 years; n=15). Allometric scaling factors, representing percent difference in 20-m time per percent difference in strength and peak power, were derived by linear regression and were similar in the three maturity groups (-0.16%/% and -0.20%/% for strength and peak power, respectively). The moderate increase in sprint performance Pre to Mid PHV (5.7%) reduced to small (1.9%) and trivial but unclear (0.9%) magnitudes after adjustment for 1RM and peak power, while the moderate increase Mid to Post PHV (4.6%) were still moderate (3.4 and 3.0%) after adjustment. Thus percent differences in strength or power explained most of the maturity-related improvements in sprint performance before PHV age but only some improvements after PHV age. Factors in addition to strength and power should be identified and monitored for development of speed in athletes during puberty. © Georg Thieme Verlag KG Stuttgart · New York.

Effects of 18-week in-season heavy-resistance and power training on throwing velocity, strength, jumping, and maximal sprint swim performance of elite male water polo players.

PubMed

Ramos Veliz, Rafael; Requena, Bernardo; Suarez-Arrones, Luis; Newton, Robert U; Sáez de Villarreal, Eduardo

2014-04-01

We examined the effects of 18 weeks of strength and high-intensity training on key sport performance measures of elite male water polo (WP) players. Twenty-seven players were randomly assigned to 2 groups, control (in-water training only) and strength group, (strength training sessions [twice per week] + in-water training). In-water training was conducted 5 d·wk. Twenty-meter maximal sprint swim, maximal dynamic strength 1-repetition maximum (1RM) for upper bench press (BP) and lower full squat (FS) body, countermovement jump (CMJ), and throwing velocity were measured before and after the training. The training program included upper and lower body strength and high-intensity exercises (BP, FS, military press, pull-ups, CMJ loaded, and abs). Baseline-training results showed no significant differences between the groups in any of the variables tested. No improvement was found in the control group; however, meaningful improvement was found in all variables in the experimental group: CMJ (2.38 cm, 6.9%, effect size [ES] = 0.48), BP (9.06 kg, 10.53%, ES = 0.66), FS (11.06 kg, 14.21%, ES = 0.67), throwing velocity (1.76 km·h(-1), 2.76%, ES = 0.25), and 20-m maximal sprint swim (-0.26 seconds, 2.25%, ES = 0.29). Specific strength and high-intensity training in male WP players for 18 weeks produced a positive effect on performance qualities highly specific to WP. Therefore, we propose modifications to the current training methodology for WP players to include strength and high-intensity training for athlete preparation in this sport.

Searching for the fastest dynamo: laminar ABC flows.

PubMed

Alexakis, Alexandros

2011-08-01

The growth rate of the dynamo instability as a function of the magnetic Reynolds number R(M) is investigated by means of numerical simulations for the family of the Arnold-Beltrami-Childress (ABC) flows and for two different forcing scales. For the ABC flows that are driven at the largest available length scale, it is found that, as the magnetic Reynolds number is increased: (a) The flow that results first in a dynamo is the 2 1/2-dimensional flow for which A=B and C=0 (and all permutations). (b) The second type of flow that results in a dynamo is the one for which A=B≃2C/5 (and permutations). (c) The most symmetric flow, A=B=C, is the third type of flow that results in a dynamo. (d) As R(M) is increased, the A=B=C flow stops being a dynamo and transitions from a local maximum to a third-order saddle point. (e) At larger R(M), the A=B=C flow reestablishes itself as a dynamo but remains a saddle point. (f) At the largest examined R(M), the growth rate of the 2 1/2-dimensional flows starts to decay, the A=B=C flow comes close to a local maximum again, and the flow A=B≃2C/5 (and permutations) results in the fastest dynamo with growth rate γ≃0.12 at the largest examined R(M). For the ABC flows that are driven at the second largest available length scale, it is found that (a) the 2 1/2-dimensional flows A=B,C=0 (and permutations) are again the first flows that result in a dynamo with a decreased onset. (b) The most symmetric flow, A=B=C, is the second type of flow that results in a dynamo. It is, and it remains, a local maximum. (c) At larger R(M), the flow A=B≃2C/5 (and permutations) appears as the third type of flow that results in a dynamo. As R(M) is increased, it becomes the flow with the largest growth rate. The growth rates appear to have some correlation with the Lyapunov exponents, but constructive refolding of the field lines appears equally important in determining the fastest dynamo flow.

The effects of phosphatidic acid supplementation on strength, body composition, muscular endurance, power, agility, and vertical jump in resistance trained men.

PubMed

Escalante, Guillermo; Alencar, Michelle; Haddock, Bryan; Harvey, Phillip

2016-01-01

Phosphatidic acid (PA) is a lipid messenger that has been shown to increase muscle protein synthesis via signaling stimulation of the mammalian target of rapamycin (mTOR). MaxxTOR® (MT) is a supplement that contains PA as the main active ingredient but also contains other synergistic mTOR signaling substances including L-Leucine, Beta-Hydroxy-Beta-Methylbutyrate (HMB), and Vitamin D3. Eighteen healthy strength-trained males were randomly assigned to a group that either consumed MT (n = 8, 22.0 +/- 2.5 years; 175.8 +/- 11.5 cm; 80.3 +/- 15.1 kg) or a placebo (PLA) (n = 10, 25.6 +/- 4.2 years; 174.8 +/- 9.0 cm; 88.6 +/- 16.6 kg) as part of a double-blind, placebo controlled pre/post experimental design. All participants volunteered to complete the three day per week resistance training protocol for the eight week study duration. To determine the effects of MT, participants were tested on one repetition maximum (1RM) leg press strength (LP), 1RM bench press strength (BP), push-ups to failure (PU), vertical jump (VJ), pro-agility shuttle time (AG), peak power output (P), lean body mass (LBM), fat mass (FM), and thigh muscle mass (TMM). Subjects were placed and monitored on an isocaloric diet consisting of 25 protein, 50 carbohydrates, and 25 % fat by a registered dietitian. Separate two-way mixed factorial repeated measures ANOVA's (time [Pre, Post] x group [MT and PLA] were used to investigate strength, body composition, and other performance changes. Post-hoc tests were applied as appropriate. Analysis were performed via SPSS with significance at (p ≤ 0.05). There was a significant main effect (F(1,16) = 33.30, p < 0.001) for LBM where MT significantly increased LBM when compared to the PLA group (p < 0.001). Additionally, there was a significant main effect for LP (F(1,16) = 666.74, p < 0.001) and BP (F(1,16) = 126.36, p < 0.001) where both increased significantly more in MT than PLA group (p < 0.001). No significant differences between MT and PLA were noted for FM, TMM, VJ, AG, P, or PU. The results of this eight week trial suggest that the addition of MaxxTOR® to a 3-day per week resistance training program can positively impact LBM and strength beyond the results found with exercise alone.

The effect of boron supplementation on lean body mass, plasma testosterone levels, and strength in male bodybuilders

NASA Technical Reports Server (NTRS)

Ferrando, A. A.; Green, N. R.

1993-01-01

The effect of boron supplementation was investigated in 19 male bodybuilders ages 20-27 years. Ten were given a 2.5-mg boron supplement while 9 were given a placebo every day for 7 weeks. Plasma total and free testosterone, plasma boron, lean body mass, and strength measurements were determined on Days 1 and 49 of the study. Plasma boron values were significantly (p < 0.05) different as the experimental group increased from (+/- SD) 20.1 +/- 7.7 ppb pretest to 32.6 +/- 27.6 ppb posttest, while the control group mean decreased from 15.1 +/- 14.4 ppb pretest to 6.3 +/- 5.5 ppb posttest. Analysis of variance indicated no significant effect of boron supplementation on any of the dependent variables. Both groups demonstrated significant increases in total testosterone, lean body mass, 1-RM squat, and 1-RM bench press. The findings suggest that 7 weeks of bodybuilding can increase total testosterone, lean body mass, and strength in lesser trained bodybuilders, and that boron supplementation had no effect on these measures.

The effect of boron supplementation on lean body mass, plasma testosterone levels, and strength in male bodybuilders.

PubMed

Ferrando, A A; Green, N R

1993-06-01

The effect of boron supplementation was investigated in 19 male bodybuilders ages 20-27 years. Ten were given a 2.5-mg boron supplement while 9 were given a placebo every day for 7 weeks. Plasma total and free testosterone, plasma boron, lean body mass, and strength measurements were determined on Days 1 and 49 of the study. Plasma boron values were significantly (p < 0.05) different as the experimental group increased from (+/- SD) 20.1 +/- 7.7 ppb pretest to 32.6 +/- 27.6 ppb posttest, while the control group mean decreased from 15.1 +/- 14.4 ppb pretest to 6.3 +/- 5.5 ppb posttest. Analysis of variance indicated no significant effect of boron supplementation on any of the dependent variables. Both groups demonstrated significant increases in total testosterone, lean body mass, 1-RM squat, and 1-RM bench press. The findings suggest that 7 weeks of bodybuilding can increase total testosterone, lean body mass, and strength in lesser trained bodybuilders, and that boron supplementation had no effect on these measures.

High-Dimensional Exploratory Item Factor Analysis by a Metropolis-Hastings Robbins-Monro Algorithm

ERIC Educational Resources Information Center

Cai, Li

2010-01-01

A Metropolis-Hastings Robbins-Monro (MH-RM) algorithm for high-dimensional maximum marginal likelihood exploratory item factor analysis is proposed. The sequence of estimates from the MH-RM algorithm converges with probability one to the maximum likelihood solution. Details on the computer implementation of this algorithm are provided. The…

Variants of the ankyrin repeat domain 6 gene (ANKRD6) and muscle and physical activity phenotypes among European-derived American adults.

PubMed

Van Deveire, Katherine N; Scranton, Sarah K; Kostek, Mathew A; Angelopoulos, Theodore J; Clarkson, Priscilla M; Gordon, Paul M; Moyna, Niall M; Visich, Paul S; Zoeller, Robert F; Thompson, Paul D; Devaney, Joseph M; Gordish-Dressman, Heather; Hoffman, Eric P; Maresh, Carl M; Pescatello, Linda S

2012-07-01

Ankyrin repeat domain 6 (ANKRD6) is a ubiquitous protein that associates with early development in mammals and is highly expressed in the brain, spinal cord, and heart of humans. We examined the role of 8 ANKRD6 single-nucleotide polymorphisms (SNPs) on muscle performance and habitual physical activity (PA). Single-nucleotide polymorphisms were 545 T>A (rs9362667), 485 M>L (rs61736690), 233 T>M (rs2273238), 128 I>L (rs3748085), 631 P>L (rs61739327), 122 Q>E (rs16881983), 197805 G>A (rs9344950), and 710 L>X (NOVEL). This study consisted of 922 healthy, untrained, European-derived American men (n = 376, 23.6 ± 0.3 years, 25.0 ± 0.2 kg·m(-2)) and women (n = 546, 23.2 ± 0.2 years, 24.0 ± 0.2 kg·m(-2)). Muscle strength (maximum voluntary contraction [MVC] and 1 repetition maximum [1RM]) and size (cross-sectional area [CSA]) were assessed before and after 12 weeks of unilateral resistance training (RT). A subsample (n = 536, 23.4 ± 0.2 years, 24.6 ± 0.2 kg·m(-2)) completed the Paffenbarger Physical Activity Questionnaire. Associations among ANKRD6 genotypes and muscle phenotypes were tested with repeated measure analysis of covariance (ANCOVA) and PA phenotypes with multivariate ANCOVA, with age and body mass index as covariates. ANKRD6 122 Q>E was associated with increased baseline biceps CSA. ANKRD6 545 A>T and ANKRD6 710 L>X were associated with increased 1RM and MVC in response to RT, respectively. ANKRD6 631 P>L was associated with increased biceps CSA response to RT and time spent in moderate-intensity PA among the total sample and women. ANKRD6 genetic variants were associated with the muscle size and strength response to RT and habitual PA levels. Further research is needed to validate our results and explore mechanisms for the associations we observed.

Comparison of hydrodynamic simulations with two-shockwave drive target experiments

NASA Astrophysics Data System (ADS)

Karkhanis, Varad; Ramaprabhu, Praveen; Buttler, William

2015-11-01

We consider hydrodynamic continuum simulations to mimic ejecta generation in two-shockwave target experiments, where metallic surface is loaded by two successive shock waves. Time of second shock in simulations is determined to match experimental amplitudes at the arrival of the second shock. The negative Atwood number (A --> - 1) of ejecta simulations leads to two successive phase inversions of the interface corresponding to the passage of the shocks from heavy to light media in each instance. Metallic phase of ejecta (solid/liquid) depends on shock loading pressure in the experiment, and we find that hydrodynamic simulations quantify the liquid phase ejecta physics with a fair degree of accuracy, where RM instability is not suppressed by the strength effect. In particular, we find that our results of free surface velocity, maximum ejecta velocity, and maximum ejecta areal density are in excellent agreement with their experimental counterparts, as well as ejecta models. We also comment on the parametric space for hydrodynamic simulations in which they can be used to compare with the target experiments.

Differences in the Load-Velocity Profile Between 4 Bench-Press Variants.

PubMed

García-Ramos, Amador; Pestaña-Melero, Francisco Luis; Pérez-Castilla, Alejandro; Rojas, Francisco Javier; Haff, Guy Gregory

2018-03-01

To compare the load-velocity relationship between 4 variants of the bench-press (BP) exercise. The full load-velocity relationship of 30 men was evaluated by means of an incremental loading test starting at 17 kg and progressing to the individual 1-repetition maximum (1RM) in 4 BP variants: concentric-only BP, concentric-only BP throw (BPT), eccentric-concentric BP, and eccentric-concentric BPT. A strong and fairly linear relationship between mean velocity (MV) and %1RM was observed for the 4 BP variants (r 2  > .96 for pooled data and r 2  > .98 for individual data). The MV associated with each %1RM was significantly higher in the eccentric-concentric technique than in the concentric-only technique. The only significant difference between the BP and BPT variants was the higher MV with the light to moderate loads (20-70%1RM) in the BPT using the concentric-only technique. MV was significantly and positively correlated between the 4 BP variants (r = .44-.76), which suggests that the subjects with higher velocities for each %1RM in 1 BP variant also tend to have higher velocities for each %1RM in the 3 other BP variants. These results highlight the need for obtaining specific equations for each BP variant and the existence of individual load-velocity profiles.

Effects of resistance training using known vs unknown loads on eccentric-phase adaptations and concentric velocity.

PubMed

Hernández-Davó, J L; Sabido, R; Behm, D G; Blazevich, A J

2018-02-01

The aims of this study were to compare both eccentric- and concentric-phase adaptations in highly trained handball players to 4 weeks of twice-weekly rebound bench press throw training with varying loads (30%, 50% and 70% of one-repetition maximum [1-RM]) using either known (KL) or unknown (UL) loads and to examine the relationship between changes in eccentric- and concentric-phase performance. Twenty-eight junior team handball players were divided into two experimental groups (KL or UL) and a control group. KL subjects were told the load prior each repetition, while UL were blinded. For each repetition, the load was dropped and then a rebound bench press at maximum velocity was immediately performed. Both concentric and eccentric velocity as well as eccentric kinetic energy and musculo-articular stiffness prior to the eccentric-concentric transition were measured. Results showed similar increases in both eccentric velocity and kinetic energy under the 30% 1-RM but greater improvements under 50% and 70% 1-RM loads for UL than KL. UL increased stiffness under all loads (with greater magnitude of changes). KL improved concentric velocity only under the 30% 1-RM load while UL also improved under 50% and 70% 1-RM loads. Improvements in concentric movement velocity were moderately explained by changes in eccentric velocity (R 2 =.23-.62). Thus, UL led to greater improvements in concentric velocity, and the improvement is potentially explained by increases in the speed (as well as stiffness and kinetic energy) of the eccentric phase. Unknown load training appears to have significant practical use for the improvement of multijoint stretch-shortening cycle movements. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Improving fitness of elite handball players: small-sided games vs. high-intensity intermittent training.

PubMed

Iacono, Antonio Dello; Eliakim, Alon; Meckel, Yoav

2015-03-01

The present study was designed to compare the effects of high-intensity intermittent training (HIIT) and small-sided games (SSGs) training on fitness variables of elite handball players. Eighteen highly trained players (mean age ± SD: 25.6 ± 0.5 years) were assigned to either HIIT or SSGs group training protocols twice per week for 8 weeks. The HIIT consisted of 12-24 × 15 seconds of high-intensity runs interspersed by 15 seconds of recovery. The SSGs training consisted of 3 against 3 small-sided handball games. Both training methods were matched for exercise duration and recovery at each training session. Before and after 8-week training, the following fitness variables were assessed-speed: 10- and 20-m sprint time, agility: handball agility specific test (HAST), upper arm strength: 1 repetition maximum (1RM) bench press test, lower limb power: counter-movement jump tests with (CMJarm) and without (CMJ) arm movement, and aerobic fitness (yo-yo intermittent recovery test level 1 [YYIRTL1]). Significant improvement was found in the YYIRTL1 (23.3 and 26.3%, respectively), 10-m sprint (2.3 and 4.1%, respectively) and 20-m sprint (2.1 and 4%, respectively), HAST (1.1 and 2.2%, respectively), 1RM bench press (6.8 and 12.3%, respectively), CMJ (7.4 and 10.8%, respectively), and CMJarm (6.4 and 8.9%, respectively) following training in both groups (p ≤ 0.05 for all). There was a significantly greater improvement in 10- and 20-m sprint, HAST, 1RM, CMJ, and CMJarm following the SSGs training compared with the HIIT (p ≤ 0.05 for all). These results indicated that both HIIT and SSGs are effective training methods for fitness development among elite adult handball players. However, SSGs training may be considered as the preferred training regimen for improving handball-specific fitness variables during the in-season period.

Comparison of Olympic vs. traditional power lifting training programs in football players.

PubMed

Hoffman, Jay R; Cooper, Joshua; Wendell, Michael; Kang, Jie

2004-02-01

Twenty members of an National Collegiate Athletic Association Division III collegiate football team were assigned to either an Olympic lifting (OL) group or power lifting (PL) group. Each group was matched by position and trained 4-days.wk(-1) for 15 weeks. Testing consisted of field tests to evaluate strength (1RM squat and bench press), 40-yard sprint, agility, vertical jump height (VJ), and vertical jump power (VJP). No significant pre- to posttraining differences were observed in 1RM bench press, 40-yard sprint, agility, VJ or in VJP in either group. Significant improvements were seen in 1RM squat in both the OL and PL groups. After log10-transformation, OL were observed to have a significantly greater improvement in Delta VJ than PL. Despite an 18% greater improvement in 1RM squat (p > 0.05), and a twofold greater improvement (p > 0.05) in 40-yard sprint time by OL, no further significant group differences were seen. Results suggest that OL can provide a significant advantage over PL in vertical jump performance changes.

Suppression of ectomycorrhizae on canopy tree seedlings in Rhododendron maximum (Eriqceae) thickets in the southern Appalachians

Treesearch

John F. Walker; Orson K. Miller; Tom Lei; Shawn Semones; Erik Nilsen; B.D. Clinton

1999-01-01

Thickets of Rhododendron maximum (Ericaceae) (Rm) is the southern Appalachians severely limit regeneration of hardwood and coniferous seedlings. Experimental blocks were established in and out of Rm thickets in a mature, mixed hardwood/conifer forest in Macon County, N.C. Litter and organic layer substrates were removed, cornposited and...

Evaluative Testing of Sheep Ranching Site 5LA2316, 5LA2366, and 5LA2359 on the Pinon Canyon Maneuver Site, Las Animas County, Colorado

DTIC Science & Technology

2009-06-01

postcard. Sincerely, Steven L. De Vore, Archeologist (402) 437-5392 Ext. 141 steve_de_vore@nps.gov Enclosures Federal laws protect the resources on...known Coulomb equation, S = c + • tan D Where S is shear strength (in units of stress), c is cohesion, is normal stress, and U is the angle of...1 9 9 9 9 - H H h- _; J _J J 0 J y :> ^ K 00 •~r. 3 Q i -a c in de te rm ir in de te rm ir al co ho l w in do w g in de te rm ir ^ ite

The acute potentiating effects of back squats on athlete performance.

PubMed

Crewther, Blair T; Kilduff, Liam P; Cook, Christian J; Middleton, Matt K; Bunce, Paul J; Yang, Guang-Zhong

2011-12-01

Crewther, BT, Kilduff, LP, Cook, CJ, Middleton, MK, Bunce, PJ, and Yang, G-Z. The acute potentiating effects of back squats on athlete performance. J Strength Cond Res 25(12): 3319-3325, 2011-This study examined the acute potentiating effects of back squats on athlete performance with a specific focus on movement specificity and the individual timing of potentiation. Nine subelite male rugby players performed 3 protocols on separate occasions using a randomized, crossover, and counterbalanced design. Each protocol consisted of performance testing before a single set of 3 repetition maximum (3RM) back squats, followed by retesting at ∼15 seconds, 4, 8, 12, and 16 minutes. The 3 tests were countermovement jumps (CMJs), sprint performance (5 and 10 m), and 3-m horizontal sled pushes with a 100-kg load. Relationships between the individual changes in salivary testosterone and cortisol concentrations and performance were also examined. The 3RM squats significantly (p < 0.001) improved CMJ height at 4 (3.9 ± 1.9%), 8 (3.5 ± 1.5%), and 12 (3.0 ± 1.4%) minutes compared with baseline values, but no temporal changes in sprinting and sled times were identified. On an individual level, the peak relative changes in CMJ height (6.4 ± 2.1%, p < 0.001) were greater than the 3-m sled (1.4 ± 0.6%), 5-m (2.6 ± 1.0%), and 10-m sprint tests (1.8 ± 1.0%). In conclusion, a single set of 3RM squats was found effective in acutely enhancing CMJ height in the study population, especially when the recovery period was individualized for each athlete. The study results also suggest that the potentiating effects of squats may exhibit some degree of movement specificity, being greater for those exercises with similar movement patterns. The current findings have practical implications for prescribing warm-up exercises, individualizing training programs, and for interpreting postactivation potentiation research.

Resistance Training Improves Muscle Function and Cardiometabolic Risks But Not Quality of Life in Older People With Type 2 Diabetes Mellitus: A Randomized Controlled Trial.

PubMed

Hsieh, Ping-Lun; Tseng, Chin-Hsiao; Tseng, Yufeng Jane; Yang, Wei-Shiung

In older people with type 2 diabetes mellitus (T2DM), the effects of aging and T2DM may compromise the function of skeletal muscle, deteriorate metabolic status, and jeopardize physical performance, aerobic capacity, and quality of life (QoL). The purpose of this study was to investigate the effects of 12 weeks of resistance training (RT) on muscle function, physical performance, cardiometabolic risks, and QoL in older people with T2DM. This study was a randomized controlled trial that employed block randomization, assessor blinding, and the intention-to-treat principle. Thirty people 65 years or older with a diagnosis of T2DM were randomly assigned to either an exercise group or a control group and were further stratified by gender. The exercise group performed 8 RT exercises in 3 sets of 8 to 12 repetitions at 75% 1-repetition maximum (1-RM) 3 times per week for 12 weeks. The control group received usual care and maintained their daily activities and lifestyle. Muscle function (1-RM and muscle oxygenation responses), physical performance (5-repetition sit-to-stand test and Timed Up and Go test), cardiometabolic risks (aerobic capacity, blood pressure, body composition, glycemic control, lipids levels, and high-sensitivity C-reactive protein levels), and QoL (Audit of Diabetes-Dependent Quality of Life 19) were assessed at baseline (week 0) and after the 12-week interventions (week 12). The 1-RM chest-press and leg-press strength and physical performance in 5-repetition sit-to-stand test were significantly improved in the exercise group compared with the controls after the interventions. The exercise group had significantly lower resting systolic blood pressure (by -12.1 mm Hg, P = 0.036) than did the controls after 12 weeks of RT, without any significant within-group change in either group after intervention. The waist circumference, fasting glucose levels, and peak diastolic blood pressure tended to favor RT over usual care after the interventions. Twelve weeks of RT increased the maximal strength in chest-press and leg-press tests, and improved 5-repetition sit-to-stand performance in older people with T2DM. Our study demonstrated that supervised, structured RT was able to promote muscle function and alleviate cardiometabolic risks in people with T2DM 65 years or older.

Effects of Exercise Modality During Additional "High-Intensity Interval Training" on Aerobic Fitness and Strength in Powerlifting and Strongman Athletes.

PubMed

Androulakis-Korakakis, Patroklos; Langdown, Louis; Lewis, Adam; Fisher, James P; Gentil, Paulo; Paoli, Antonio; Steele, James

2018-02-01

Androulakis-Korakakis, P, Langdown, L, Lewis, A, Fisher, JP, Gentil, P, Paoli, A, and Steele, J. Effects of exercise modality during additional "high-intensity interval training" on aerobic fitness and strength in powerlifting and strongman athletes. J Strength Cond Res 32(2): 450-457, 2018-Powerlifters and strongman athletes have a necessity for optimal levels of muscular strength while maintaining sufficient aerobic capacity to perform and recover between events. High-intensity interval training (HIIT) has been popularized for its efficacy in improving both aerobic fitness and strength but never assessed within the aforementioned population group. This study looked to compare the effect of exercise modality, e.g., a traditional aerobic mode (AM) and strength mode (SM), during HIIT on aerobic fitness and strength. Sixteen well resistance-trained male participants, currently competing in powerlifting and strongman events, completed 8 weeks of approximately effort- and volume-matched HIIT in 2 groups: AM (cycling, n = 8) and SM (resistance training, n = 8). Aerobic fitness was measured as predicted V[Combining Dot Above]O2max using the YMCA 3 minutes step test and strength as predicted 1 repetition maximum from a 4-6RM test using a leg extension. Both groups showed significant improvements in both strength and aerobic fitness. There was a significant between-group difference for aerobic fitness improvements favoring the AM group (p ≤ 0.05). There was no between-group difference for change in strength. Magnitude of change using within-group effect size for aerobic fitness and strength was considered large for each group (aerobic fitness, AM = 2.6, SM = 2.0; strength, AM = 1.9, SM = 1.9). In conclusion, our results support enhanced strength and aerobic fitness irrespective of exercise modality (e.g., traditional aerobic and resistance training). However, powerlifters and strongman athletes wishing to enhance their aerobic fitness should consider HIIT using an aerobic HIIT mode.

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.

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.

Effects of systemic hypoxia on human muscular adaptations to resistance exercise training

PubMed Central

Kon, Michihiro; Ohiwa, Nao; Honda, Akiko; Matsubayashi, Takeo; Ikeda, Tatsuaki; Akimoto, Takayuki; Suzuki, Yasuhiro; Hirano, Yuichi; Russell, Aaron P.

2014-01-01

Abstract Hypoxia is an important modulator of endurance exercise‐induced oxidative adaptations in skeletal muscle. However, whether hypoxia affects resistance exercise‐induced muscle adaptations remains unknown. Here, we determined the effect of resistance exercise training under systemic hypoxia on muscular adaptations known to occur following both resistance and endurance exercise training, including muscle cross‐sectional area (CSA), one‐repetition maximum (1RM), muscular endurance, and makers of mitochondrial biogenesis and angiogenesis, such as peroxisome proliferator‐activated receptor‐γ coactivator‐1α (PGC‐1α), citrate synthase (CS) activity, nitric oxide synthase (NOS), vascular endothelial growth factor (VEGF), hypoxia‐inducible factor‐1 (HIF‐1), and capillary‐to‐fiber ratio. Sixteen healthy male subjects were randomly assigned to either a normoxic resistance training group (NRT, n =7) or a hypoxic (14.4% oxygen) resistance training group (HRT, n =9) and performed 8 weeks of resistance training. Blood and muscle biopsy samples were obtained before and after training. After training muscle CSA of the femoral region, 1RM for bench‐press and leg‐press, muscular endurance, and skeletal muscle VEGF protein levels significantly increased in both groups. The increase in muscular endurance was significantly higher in the HRT group. Plasma VEGF concentration and skeletal muscle capillary‐to‐fiber ratio were significantly higher in the HRT group than the NRT group following training. Our results suggest that, in addition to increases in muscle size and strength, HRT may also lead to increased muscular endurance and the promotion of angiogenesis in skeletal muscle. PMID:24907297

Influence of variable resistance loading on subsequent free weight maximal back squat performance.

PubMed

Mina, Minas A; Blazevich, Anthony J; Giakas, Giannis; Kay, Anthony D

2014-10-01

The purpose of the study was to determine the potentiating effects of variable resistance (VR) exercise during a warm-up on subsequent free-weight resistance (FWR) maximal squat performance. In the first session, 16 recreationally active men (age = 26.0 ± 7.8 years; height = 1.7 ± 0.2 m; mass = 82.6 ± 12.7 kg) were familiarized with the experimental protocols and tested for 1 repetition maximum (1RM) squat lift. The subjects then visited the laboratory on 2 further occasions under either control or experimental conditions. During these conditions, 2 sets of 3 repetitions of either FWR (control) or VR (experimental) squat lifts at 85% of 1RM were performed; during the experimental condition, 35% of the load was generated from band tension. After a 5-minute rest, 1RM, 3D knee joint kinematics, and vastus medialis, vastus lateralis, rectus femoris, and semitendinosus electromyogram (EMG) signals were recorded simultaneously. No subject increased 1RM after FWR, however, 13 of 16 (81%) subjects increased 1RM after VR (mean = 7.7%; p < 0.01). Lower peak and mean eccentric (16-19%; p ≤ 0.05) and concentric (12-21%; p ≤ 0.05) knee angular velocities were observed during the 1RM following VR when compared with FWR, however, no differences in knee flexion angle (1.8°; p > 0.05) or EMG amplitudes (mean = 5.9%; p > 0.05) occurred. Preconditioning using VR significantly increased 1RM without detectable changes in knee extensor muscle activity or knee flexion angle, although eccentric and concentric velocities were reduced. Thus, VR seems to potentiate the neuromuscular system to enhance subsequent maximal lifting performance. Athletes could thus use VR during warm-up routines to maximize squat performance.

Effect of Resistance Training Frequency on Gains in Muscular Strength: A Systematic Review and Meta-Analysis.

PubMed

Grgic, Jozo; Schoenfeld, Brad J; Davies, Timothy B; Lazinica, Bruno; Krieger, James W; Pedisic, Zeljko

2018-05-01

Current recommendations on resistance training (RT) frequency for gains in muscular strength are based on extrapolations from limited evidence on the topic, and thus their practical applicability remains questionable. To elucidate this issue, we conducted a systematic review and meta-analysis of the studies that compared muscular strength outcomes with different RT frequencies. To carry out this review, English-language literature searches of the PubMed/MEDLINE, Scopus, and SPORTDiscus databases were conducted. The meta-analysis was performed using a random-effects model. The meta-analysis models were generated with RT frequencies classified as a categorical variable as either 1, 2, 3, or 4+ times/week, or, if there were insufficient data in subgroup analyses, the training frequencies were categorized as 1, 2, or 3 times/week. Subgroup analyses were performed for potential moderators, including (1) training volume; (2) exercise selection for the 1 repetition maximum (RM) test (for both multi-joint and single-joint exercises); (3) upper and lower body strength gains; (4) training to muscular failure (for studies involving and not involving training to muscular failure); (5) age (for both middle-aged/older adults and young adults); and (6) sex (for men and for women). The methodological quality of studies was appraised using the modified Downs and Black checklist. A total of 22 studies were found to meet the inclusion criteria. The average score on the Downs and Black checklist was 18 (range 13-22 points). Four studies were classified as being of good methodological quality, while the rest were classified as being of moderate methodological quality. Results of the meta-analysis showed a significant effect (p = 0.003) of RT frequency on muscular strength gains. Effect sizes increased in magnitude from 0.74, 0.82, 0.93, and 1.08 for training 1, 2, 3, and 4+ times per week, respectively. A subgroup analysis of volume-equated studies showed no significant effect (p = 0.421) of RT frequency on muscular strength gains. The subgroup analysis for exercise selection for the 1RM test suggested a significant effect of RT frequency on multi-joint (p < 0.001), but not single-joint, 1RM test results (p = 0.324). The subgroup analysis for upper and lower body showed a significant effect of frequency (p = 0.004) for upper body, but not lower body, strength gains (p = 0.070). In the subgroup analysis for studies in which the training was and was not carried out to muscular failure, no significant effect of RT frequency was found. The subgroup analysis for the age groups suggested a significant effect of training frequency among young adults (p = 0.024), but not among middle-aged and older adults (p = 0.093). Finally, the subgroup analysis for sex indicated a significant effect of RT frequency on strength gains in women (p = 0.030), but not men (p = 0.190). The results of the present systematic review and meta-analysis suggest a significant effect of RT frequency as higher training frequencies are translated into greater muscular strength gains. However, these effects seem to be primarily driven by training volume because when the volume is equated, there was no significant effect of RT frequency on muscular strength gains. Thus, from a practical standpoint, greater training frequencies can be used for additional RT volume, which is then likely to result in greater muscular strength gains. However, it remains unclear whether RT frequency on its own has significant effects on strength gain. It seems that higher RT frequencies result in greater gains in muscular strength on multi-joint exercises in the upper body and in women, and, finally, in contrast to older adults, young individuals seem to respond more positively to greater RT frequencies. More evidence among resistance-trained individuals is needed as most of the current studies were performed in untrained participants.

Concordance and discordance between two measures of lower extremity function: 400 meter self-paced walk and SPPB.

PubMed

Sayers, Stephen P; Guralnik, Jack M; Newman, Anne B; Brach, Jennifer S; Fielding, Roger A

2006-04-01

The purpose of the study was to assess the concurrent validity of the 400 meter self-paced walk test (400-m W) against the commonly used short physical performance battery (SPPB). A secondary purpose was to determine whether the 400-m W could better discriminate physical performance among high functioning older adults by examining the distribution of 400-m W scores. 101 men and women (80.8+/-0.4 years) were recruited to participate in the study. The 400-mW and SPPB assessed lower extremity function. Lower extremity muscle strength, power, and contraction velocity was assessed using bilateral leg press (LP). Health history was obtained with questionnaire. 400-m W demonstrated moderate correlations with SPPB (Pearson r=0.74; p< 0.001). In 36 high functioning individuals (SPPB score= 10, 11, 12), participants above the median 400-m W performance time (n=20) had more medical conditions (2.8+/-0.4 vs 1.7+/-0.3; p=0.038), more reported falls (0.80+/-0.2 vs 0.19+/-0.1; p=0.016), more medications (3.7+/-0.4 vs 1.8+/-0.4; p=0.001), had lower LP power at 70% of the one repetition maximum (1RM) (336+/-45 W vs 663+/-78 W; p=0.001) and 40% 1RM (329+/-43 W vs 580+/-75 W; p=0.005), and had slower LP contraction velocity at 40% 1RM (77+/-5.5 m/s vs 112+/-8.4 m/s; p=0.001) compared with those below the median (n=16). A substantial number of apparently well functioning older adults demonstrated some limitations in the ability to walk 400 meters. Use of the 400-m W may be justified to obtain information to better discriminate among high functioning elderly.

Hematological and Hemodynamic Responses to Acute and Short-Term Creatine Nitrate Supplementation

PubMed Central

Dalton, Ryan L.; Sowinski, Ryan J.; Grubic, Tyler J.; Collins, Patrick B.; Coletta, Adriana M.; Reyes, Aimee G.; Sanchez, Brittany; Koozehchian, Majid; Rasmussen, Christopher; Greenwood, Mike; Murano, Peter S.; Kreider, Richard B.

2017-01-01

In a double-blind, crossover, randomized and placebo-controlled trial; 28 men and women ingested a placebo (PLA), 3 g of creatine nitrate (CNL), and 6 g of creatine nitrate (CNH) for 6 days. Participants repeated the experiment with the alternate supplements after a 7-day washout. Hemodynamic responses to a postural challenge, fasting blood samples, and bench press, leg press, and cycling time trial performance and recovery were assessed. Data were analyzed by univariate, multivariate, and repeated measures general linear models (GLM). No significant differences were found among treatments for hemodynamic responses, clinical blood markers or self-reported side effects. After 5 days of supplementation, one repetition maximum (1RM) bench press improved significantly for CNH (mean change, 95% CI; 6.1 [3.5, 8.7] kg) but not PLA (0.7 [−1.6, 3.0] kg or CNL (2.0 [−0.9, 4.9] kg, CNH, p = 0.01). CNH participants also tended to experience an attenuated loss in 1RM strength during the recovery performance tests following supplementation on day 5 (PLA: −9.3 [−13.5, −5.0], CNL: −9.3 [−13.5, −5.1], CNH: −3.9 [−6.6, −1.2] kg, p = 0.07). After 5 days, pre-supplementation 1RM leg press values increased significantly, only with CNH (24.7 [8.8, 40.6] kg, but not PLA (13.9 [−15.7, 43.5] or CNL (14.6 [−0.5, 29.7]). Further, post-supplementation 1RM leg press recovery did not decrease significantly for CNH (−13.3 [−31.9, 5.3], but did for PLA (−30.5 [−53.4, −7.7] and CNL (−29.0 [−49.5, −8.4]). CNL treatment promoted an increase in bench press repetitions at 70% of 1RM during recovery on day 5 (PLA: 0.4 [−0.8, 1.6], CNL: 0.9 [0.35, 1.5], CNH: 0.5 [−0.2, 0.3], p = 0.56), greater leg press endurance prior to supplementation on day 5 (PLA: −0.2 [−1.6, 1.2], CNL: 0.9 [0.2, 1.6], CNH: 0.2 [−0.5, 0.9], p = 0.25) and greater leg press endurance during recovery on day 5 (PLA: −0.03 [−1.2, 1.1], CNL: 1.1 [0.3, 1.9], CNH: 0.4 [−0.4, 1.2], p = 0.23). Cycling time trial performance (4 km) was not affected. Results indicate that creatine nitrate supplementation, up to a 6 g dose, for 6 days, appears to be safe and provide some ergogenic benefit. PMID:29244743

Effect of instruction, surface stability, and load intensity on trunk muscle activity.

PubMed

Bressel, Eadric; Willardson, Jeffrey M; Thompson, Brennan; Fontana, Fabio E

2009-12-01

The aim of this study was to assess the effect of verbal instruction, surface stability, and load intensity on trunk muscle activity levels during the free weight squat exercise. Twelve trained males performed a free weight squat under four conditions: (1) standing on stable ground lifting 50% of their 1-repetition maximum (RM), (2) standing on a BOSU balance trainer lifting 50% of their 1-RM, (3) standing on stable ground lifting 75% of their 1-RM, and (4) receiving verbal instructions to activate the trunk muscles followed by lifting 50% of their 1-RM. Surface EMG activity from muscles rectus abdominis (RA), external oblique (EO), transversus abdominis/internal oblique (TA/IO), and erector spinae (ES) were recorded for each condition and normalized for comparisons. Muscles RA, EO, and TA/IO displayed greater peak activity (39-167%) during squats with instructions compared to the other squat conditions (P=0.04-0.007). Peak EMG activity of muscle ES was greater for the 75% 1-RM condition than squats with instructions or lifting 50% of 1-RM (P=0.04-0.02). The results indicate that if the goal is to enhance EMG activity of the abdominal muscles during a multi-joint squat exercise then verbal instructions may be more effective than increasing load intensity or lifting on an unstable surface. However, in light of other research, conscious co-activation of the trunk muscles during the squat exercise may lead to spinal instability and hazardous compression forces in the lumbar spine.

Maximal Strength Performance and Muscle Activation for the Bench Press and Triceps Extension Exercises Adopting Dumbbell, Barbell, and Machine Modalities Over Multiple Sets.

PubMed

Farias, Déborah de Araújo; Willardson, Jeffrey M; Paz, Gabriel A; Bezerra, Ewertton de S; Miranda, Humberto

2017-07-01

Farias, DdA, Willardson, JM, Paz, GA, Bezerra, EdS, and Miranda, H. Maximal strength performance and muscle activation for the bench press and triceps extension exercises adopting dumbbell, barbell and machine modalities over multiple sets. J Strength Cond Res 31(7): 1879-1887, 2017-The purpose of this study was to investigate muscle activation, total repetitions, and training volume for 3 bench press (BP) exercise modes (Smith machine [SMBP], barbell [BBP], and dumbbell [DBP]) that were followed by a triceps extension (TE) exercise. Nineteen trained men performed 3 testing protocols in random order, which included: (P1) SMBP + TE; (P2) BBP + TE; and (P3) DBP + TE. Each protocol involved 4 sets with a 10-repetition maximum (RM) load, immediately followed by a TE exercise that was also performed for 4 sets with a 10RM load. A 2-minute rest interval was adopted between sets and exercises. Surface electromyographic activity was assessed for the pectoralis major (PM), anterior deltoid (AD), biceps brachii (BB), and triceps brachii (TB). The results indicated that significantly higher total repetitions were achieved for the DBP (31.2 ± 3.2) vs. the BBP (27.8 ± 4.8). For the TE, significantly greater volume was achieved when this exercise was performed after the BBP (1,204.4 ± 249.4 kg) and DBP (1,216.8 ± 287.5 kg) vs. the SMBP (1,097.5 ± 193 kg). The DBP elicited significantly greater PM activity vs. the BBP. The SMBP elicited significantly greater AD activity vs. the BBP and DBP. During the different BP modes, the SMBP and BBP elicited significantly greater TB activity vs. the DBP. However, the DBP elicited significantly greater BB activity vs. the SMBP and BBP, respectively. During the succeeding TE exercise, significantly greater activity of the TB was observed when this exercise was performed after the BBP vs. the SMBP and DBP. Therefore, it seems that the variation in BP modes does influence both repetition performance and muscle activation patterns during the TE when these exercises are performed in succession.

Relationships among peak power output, peak bar velocity, and mechanomyographic amplitude during the free-weight bench press exercise.

PubMed

Stock, Matt S; Beck, Travis W; Defreitas, Jason M; Dillon, Michael A

2010-10-01

The purpose of this study was to examine the relationships among mechanomyographic (MMG) amplitude, power output, and bar velocity during the free-weight bench press exercise. Twenty-one resistance-trained men [one-repetition maximum (1-RM) bench press = 125.4+18.4 kg] performed bench press muscle actions as explosively as possible from 10% to 90% of the 1-RM while peak power output and peak bar velocity were assessed with a TENDO Weightlifting Analyzer. During each muscle action, surface MMG signals were detected from the right and left pectoralis major and triceps brachii, and the concentric portion of the range of motion was selected for analysis. Results indicated that power output increased from 10% to 50% 1-RM, followed by decreases from 50% to 90% 1-RM, but MMG amplitude for each of the muscles increased from 10 to 80% 1-RM. The results of this study indicate that during the free-weight bench press exercise, MMG amplitude was not related to power output, but was inversely related to bar velocity and directly related to the external load being lifted. In future research, coaches and sport scientists may be able to estimate force/torque production from individual muscles during multi-joint, dynamic constant external resistance muscle actions.

Vortex Flux Pinning in Type-Ii Superconductors

NASA Astrophysics Data System (ADS)

Hasan, Mohammad-Khair A. M.

1995-01-01

Rotational magnetization vector measurements on polycrystalline samples of rm YBa_2Cu _3O_7 (YBCO) and (Ba, K)BiO _3 at various fixed fields (H) and temperatures (T) reveal that the vortex flux density (B) in a rotational state consists of a component B_{rm R}, which rotates rigidly with sample rotation, and a B_{rm F} component, which stays at a fixed frictional angle (theta _{rm F}) relative to H. Also, B_{rm R} decreases and ultimately vanishes with increasing H, while B _{rm F} grows monotonically, implying that the vortex pinning strength have a broad distribution. This has been confirmed by the measurements on YBCO of the remanent flux density B^ {rm rm} which can be decomposed analogously into B_{R} ^{} and B_ {F}^{} at angle theta_{F}^{} relative to H. The quantity Hsin theta_{rm F},, which at equilibrium equals tau_{rm p}/mu (the average pinning torque per vortex of moment mu) decreases with increasing high H. This result and the distribution in the strength of the pinning are shown to be consistent with the collective pinning process of vortex bundling. At fixed H, tau_{rm p} decreases rapidly with increasing T, varying approximately as T^{-0.8} for both samples. For polycrystalline YBCO at 4.2 K, B_ {rm R} and B_{ rm F} are found to relax differently with time. The negative creep sign of B_ {rm R} indicates that the number of rotational vortices decreases with time, whereas B _{rm F} shows a positive creep with a negative change in theta_ {rm F}, which indicates that more frictional vortices enter the sample with a tendency of alignment in the direction of H. For grain-oriented YBCO at 4.2 K, the vortex creep measurements of B along the c-axis at different fields showed that: whenever the hysteretic changes of H are reversed in sign, the vortex flux creep (dB/dlogt) decreases very rapidly to zero, where it lingers before changing sign. At the same turning values of H, (dB/dH) also goes to zero. These properties are attributable to the reversals of the vortex motion which occur at the turning values of H and cause a reversal of frictional pinning forces.

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

Exercises with partial vascular occlusion in patients with knee osteoarthritis: a randomized clinical trial.

PubMed

Bryk, Flavio Fernandes; Dos Reis, Amir Curcio; Fingerhut, Deborah; Araujo, Thomas; Schutzer, Marcela; Cury, Ricardo de Paula Leite; Duarte, Aires; Fukuda, Thiago Yukio

2016-05-01

The objective of this study was to evaluate whether women with knee osteoarthritis performing a rehabilitation programme consisting of low-load exercises combined with PVO exhibited the same results in changes in quadriceps strength, pain relief, and functional improvement when compared to women receiving a programme consisting of high-load exercises without PVO. Thirty-four women (mean age, 61 years) with a diagnosis of knee osteoarthritis were randomly assigned to a conventional or occlusion group. The women in the conventional group (n = 17) performed a 6-week quadriceps strengthening and stretching programme using a load around 70 % of the 1-repetition maximum (RM). The women in the occlusion group (n = 17) performed the same programme, however, only using a load around 30 % of the 1-RM, while PVO was induced. The PVO was achieved using a pressure cuff applied to the upper third of the thigh and inflated to 200 mmHg during the quadriceps exercise. An 11-point Numerical Pain Rating Scale (NPRS), the Lequesne questionnaire, the Timed-Up and Go (TUG) test, and muscle strength measurement using a hand-held dynamometer were used as outcome measures at baseline (pretreatment) and at the end of the 6-week of treatment. Pain, using the NPRS, was also assessed when performing the quadriceps exercises during the exercise sessions. At baseline, demographic, strength, pain, and functional assessment data were similar between groups. Patients from both the conventional and occlusion groups had a higher level of function (Lequesne and TUG test), less pain (NPRS), and higher quadriceps strength at the 6-week evaluation when compared to baseline (all P < 0.05). However, the between-group analysis showed no differences for all outcomes variables at posttreatment (n.s.). Patients in the occlusion group experienced less anterior knee discomfort during the treatment sessions than those in the high-load exercise group (P < 0.05). A rehabilitation programme that combined PVO to low-load exercise resulted in similar benefits in pain, function, and quadriceps strength than a programme using high-load conventional exercise in patients with knee osteoarthritis. However, the use of PVO combined with low-load exercise resulted in less anterior knee pain during the training sessions. I.

The Acute Effect of Upper-Body Complex Training on Power Output of Martial Art Athletes as Measured by the Bench Press Throw Exercise

PubMed Central

Liossis, Loudovikos Dimitrios; Forsyth, Jacky; Liossis, Ceorge; Tsolakis, Charilaos

2013-01-01

The purpose of this study was to examine the acute effect of upper body complex training on power output, as well as to determine the requisite preload intensity and intra-complex recovery interval needed to induce power output increases. Nine amateur-level combat/martial art athletes completed four distinct experimental protocols, which consisted of 5 bench press repetitions at either: 65% of one-repetition maximum (1RM) with a 4 min rest interval; 65% of 1RM with an 8 min rest; 85% of 1RM with a 4 min rest; or 85% of 1RM with an 8 min rest interval, performed on different days. Before (pre-conditioning) and after (post-conditioning) each experimental protocol, three bench press throws at 30% of 1RM were performed. Significant differences in power output pre-post conditioning were observed across all experimental protocols (F=26.489, partial eta2=0.768, p=0.001). Mean power output significantly increased when the preload stimulus of 65% 1RM was matched with 4 min of rest (p=0.001), and when the 85% 1RM preload stimulus was matched with 8 min of rest (p=0.001). Moreover, a statistically significant difference in power output was observed between the four conditioning protocols (F= 21.101, partial eta2=0.913, p=0.001). It was concluded that, in complex training, matching a heavy preload stimulus with a longer rest interval, and a lighter preload stimulus with a shorter rest interval is important for athletes wishing to increase their power production before training or competition. PMID:24511352

Gamow-Teller Strength for the Mixed Ground State of ARGON-35 via the (proton, Neutron) Reaction.

NASA Astrophysics Data System (ADS)

Wagner, Anthony James

1988-12-01

Early asymmetry measurements of the mixed beta-decay of the ground state of ^{35}Ar to the ground state of ^{35}Cl showed an "anomalous" value of G_{rm V}. This anomalous value surprisingly would infer that unitary symmetry, believed to be spontaneously broken in nature, has been restored in this singular case. From the definition of rho^2, this "anomalous" value also infers a "anomalous" value for B(GT)/B(F). When the half-life data is used instead without the results of the asymmetry experiment, one obtains a different ("normal") value of B(GT)/B(F). The quantity rho^2 derived from the early asymmetry experiments is considered suspect. It has recently been shown that the (p,n) reaction at intermediate energies provides a strong interaction probe of the identical B(GT)/B(F) nuclear strength ratio that can be measured in beta-decay. The value of G_{rm A}/G _{rm V} has been determined very accurately from the beta -decay of the neutron. Thus, (p,n) can be used to determine via a totally independent measurement the value of B(GT)/B(F). The global proportionality constant E _{rm O} = 55 +/- 0.4 MeV is used to analyze the results of a 160 MeV Polarimeter experiment to distinguish between the normal and anomalous value. The results showed more spin-flip probability than was expected. A 120 MeV cross section experiment was required to check whether there was additional spin-flip probability due to a non-negligible DeltaL = 2 component. The results showed a negligible DeltaL = 2 component. The specific proportionality ({ sigma}_{rm GT} (Ground State) = {sigma} _{rm GT} (Excited State)) was then used to reanalyze the results of both experiments. The results showed a B(GT)/B(F) = 0.058 +/- 0.007. The specific proportionality gave a global proportionality constant of E_{rm O} = 32.2 +/- 1.9 MeV. The reason for this deviation in E_{rm O} is not understood.

Effect of loading on peak power of the bar, body, and system during power cleans, squats, and jump squats.

PubMed

McBride, Jeffrey M; Haines, Tracie L; Kirby, Tyler J

2011-08-01

Nine males (age 24.7 ± 2.1 years, height 175.3 ± 5.5 cm, body mass 80.8 ± 7.2 kg, power clean 1-RM 97.1 ± 6.36 kg, squat 1-RM = 138.3 ± 20.9 kg) participated in this study. On day 1, the participants performed a one-repetition maximum (1-RM) in the power clean and the squat. On days 2, 3, and 4, participants performed the power clean, squat or jump squat. Loading for the power clean ranged from 30% to 90% of the participant's power clean 1-RM and loading for the squat and jump squat ranged from 0% to 90% of the participant's squat 1-RM, all at 10% increments. Peak force, velocity, and power were calculated for the bar, body, and system (bar + body) for all power clean, squat, and jump squat trials. Results indicate that peak power for the bar, body, and system is differentially affected by load and movement pattern. When using the power clean, squat or jump squat for training, the optimal load in each exercise may vary. Throwing athletes or weightlifters may be most concerned with bar power, but jumpers or sprinters may be more concerned with body or system power. Thus, the exercise type and load vary according to the desired stimulus.

The Chronic Effects of Low- and High-Intensity Resistance Training on Muscular Fitness in Adolescents

PubMed Central

Assunção, Ari R.; Bottaro, Martim; Ferreira-Junior, João B.; Izquierdo, Mikel; Cadore, Eduardo L.; Gentil, Paulo

2016-01-01

To compare the effects of high-load, low-repetition maximum (LRM) and low-load, high-repetition maximum (HRM) resistance training regimens on muscular fitness in untrained adolescents. Forty-five untrained adolescents of both sexes (13.7±0.8 years; 161.3±7.5 cm, 56.8±13.4 kg) were randomly assigned into one of three groups: 1) LRM (n = 17): volunteers performed three sets of 4-6-repetition maximum (RM); 2) HRM (n = 16): volunteers performed three sets of 12–15 RM; and 3) control (CON, n = 12). Training was performed two times a week for 9 weeks. After training, there were significant increases in 1 RM chest press (LRM = 14.8% and HRM = 14.2%, p<0.05) and squat (LRM = 26.4% and HRM = 25.7%, p<0.05), with no differences between the LRM and HRM groups (p>0.05). Additionally, muscular endurance increased significantly for the chest press (LRM = 14.5% and HRM = 21.8%, p<0.05) and squat test (LRM = 31.4% and HRM = 32.4%, p<0.05) following resistance training, with no difference between the LRM and HRM groups (p>0.05). These results suggest that both high-load, low-repetition and moderate-load, high-repetition resistance training can be prescribed to improve muscular fitness in untrained adolescents. PMID:27509050

Seasonal Strength Performance and Its Relationship with Training Load on Elite Runners

PubMed Central

Balsalobre-Fernández, Carlos; Tejero-González, Carlos M.; del Campo-Vecino, Juan

2015-01-01

The aim of this study was to analyze the time-course of force production of elite middle and long-distance runners throughout an entire season and at the end of the off-season, as well as its relationships with training load and hormonal responses. Training load was recorded daily throughout an entire season by measuring and evaluating the session distance (km), training zone and session-RPE in a group of 15 elite middle and long-distance runners (12 men, 3 women; age = 26.3 ± 5.1yrs, BMI = 19.7 ± 1.1). Also, basal salivary-free cortisol levels were measured weekly, and 50-metre sprints, mean propulsive velocity (MPV), mean propulsive power (MPP), repetition maximum (RM) and peak rate of force development (RFD) of half-squats were measured 4 times during the season, and once more after the off-season break. There were no significant variations in force production during the season or after the off-season break, except for the RFD (-30.2%, p = 0.005) values, which changed significantly from the beginning to the end of the season. Significant correlations were found between session-RPE and MPV (r = -0.650, p = 0.004), MPP (r = -0.602, p = 0.009), RM (r = -0.650, p = 0.004), and the 50-metre sprint (r = 0.560, p = 0.015). Meanwhile, salivary-free cortisol correlated significantly with the 50-metre sprint (r = 0.737, p < 0.001) and the RM ( r = -0.514, p = 0.025). Finally, the training zone correlated with the 50-metre sprint (r = -0.463, p = 0.041). Session-RPE, training zone and salivary-free cortisol levels are related to force production in elite middle and long-distance runners. Monitoring these variables could be a useful tool in controlling the training programs of elite athletes. Key points Session-RPE, training zone and salivary free cortisol levels correlate significantly with strength-related variables in middle and long-distance elite runners. A month of active rest during the off-season break is enough to prevent decreases in force production of such athletes. Monitoring training loads through session-RPE is a suitable and simple method for controlling the training process in elite middle and long-distance runners. PMID:25729283

Exertional Rhabdomyolysis in a 21-Year-Old Healthy Woman: A Case Report.

PubMed

McKay, Brianna D; Yeo, Noelle M; Jenkins, Nathaniel D M; Miramonti, Amelia A; Cramer, Joel T

2017-05-01

McKay, BD, Yeo, NM, Jenkins, NDM, Miramonti, AA, and Cramer, JT. Exertional rhabdomyolysis in a 21-year-old healthy woman: a case report. J Strength Cond Res 31(5): 1403-1410, 2017-The optimal resistance training program to elicit muscle hypertrophy has been recently debated and researched. Although 3 sets of 10 repetitions at 70-80% of the 1 repetition maximum (1RM) are widely recommended, recent studies have shown that low-load (∼30% 1RM) high-repetition (3 sets of 30-40 repetitions) resistance training can elicit similar muscular hypertrophy. Incidentally, this type of resistance training has gained popularity. In the process of testing this hypothesis in a research study in our laboratory, a subject was diagnosed with exertional rhabdomyolysis after completing a resistance training session that involved 3 sets to failure at 30% 1RM. Reviewed were the events leading up to and throughout the diagnosis of exertional rhabdomyolysis in a healthy recreationally-trained 21-year-old woman who was enrolled in a study that compared the acute effects of high-load low-repetition vs. low-load high-repetition resistance training. The subject completed a total of 143 repetitions of the bilateral dumbbell biceps curl exercise. Three days after exercise, she reported excessive muscle soreness and swelling and sought medical attention. She was briefly hospitalized and then discharged with instructions to take acetaminophen for soreness, drink plenty of water, rest, and monitor her creatine kinase (CK) concentrations. Changes in the subject's CK concentrations, ultrasound-determined muscle thickness, and echo intensity monitored over a 14-day period are reported. This case illustrates the potential risk of developing exertional rhabdomyolysis after a low-load high-repetition resistance training session in healthy, young, recreationally-trained women. The fact that exertional rhabdomyolysis is a possible outcome may warrant caution when prescribing this type of resistance exercise.

Strength and Power Correlates of Throwing Velocity on Subelite Male Cricket Players.

PubMed

Freeston, Jonathan L; Carter, Thomas; Whitaker, Gary; Nicholls, Owen; Rooney, Kieron B

2016-06-01

Throwing velocity is an important aspect of fielding in cricket to affect run-outs and reduce the opponent's run-scoring opportunities. Although a relationship between strength and/or power and throwing velocity has been well established in baseball, water polo, and European handball, it has not been adequately explored in cricket. Consequently, this study aimed to determine the relationship between measures of strength and/or power and throwing velocity in cricket players. Seventeen male cricket players (mean ± SD; age, 21.1 ± 1.6 years; height, 1.79 ± 0.06 m; weight, 79.8 ± 6.4 kg) from an elite athlete program were tested for maximal throwing velocity from the stretch position and after a 3-meter shuffle. They were also assessed for strength and power using a range of different measures. Throwing velocity from the stretch position (30.5 ± 2.4 m·s) was significantly related to dominant leg lateral-to-medial jump (LMJ) distance (r = 0.71; p < 0.01), dominant shoulder internal rotation (IR) strength (r = 0.55; p ≤ 0.05), and dominant (r = 0.73; p < 0.01) and nondominant (r = 0.54; p ≤ 0.05) medicine ball rotation (MB Rot) throw velocity and medicine ball chest pass (MB CP) distance (r = 0.67; p < 0.01). A nonsignificant trend was observed for vertical jump (VJ) height (p = 0.06), whereas no significant relationships were observed for nondominant LMJ distance (p = 0.97), nondominant shoulder IR strength (p = 0.80), 1 repetition maximum (RM) squat strength (p = 0.57), 1RM bench press strength (p = 0.90), height (p = 0.33), or weight (p = 0.29). Multiple regression analysis revealed that dominant MB Rot and MB CP explained 66% of the variance. The results were similar for velocity after a shuffle step (31.8 ± 2.1 m·s); however, VJ height reached statistical significance (r = 0.51; p ≤ 0.05). The multiple regression was also similar with MB Rot and MB CP explaining 70% of the variance. The cricketers in this study threw with greater velocity than elite junior and subelite senior cricketers but with lower velocities than elite senior cricketers and collegiate level and professional baseball players. This is the first study to demonstrate a link between strength and/or power and throwing velocity in cricket players and highlight the importance of power development as it relates to throwing velocity. Exercises that more closely simulated the speed (body weight jumps and medicine ball throws) or movement pattern (shoulder IR) of overhead throwing were greater predictors of throwing velocity. Strength and conditioning staff should assess and develop power to enhance throwing performance in cricket players. Exercises with greater movement and speed specificity to throwing should be used in preference over exercises that are slower and have less movement specificity to the throwing motion. Cricket players should engage in power training to bridge the gap in performance between them and baseball players.

Mind-muscle connection training principle: influence of muscle strength and training experience during a pushing movement.

PubMed

Calatayud, Joaquin; Vinstrup, Jonas; Jakobsen, Markus D; Sundstrup, Emil; Colado, Juan Carlos; Andersen, Lars L

2017-07-01

To investigate the effect of different attentional focus conditions on muscle activity during the push-up exercise and to assess the possible influence of muscle strength and training experience. Eighteen resistance-trained men performed 1RM bench press testing and were familiarized with the procedure during the first session. In the second session, three different conditions were randomly performed: regular push-up and push-up focusing on using the pectoralis major and triceps brachii muscles, respectively. Surface electromyography (EMG) was recorded and analyzed (EMG normalized to max; nEMG) for the triceps brachii and pectoralis major muscles. Participants had on average 8 (SD 6) years of training experience and 1RM of 1.25 (SD 0.28) kg per kg bodyweight. Focusing on using pectoralis major increased activity in this muscle by 9% nEMG (95% CI 5-13; Cohen's d 0.60) compared with the regular condition. Triceps activity was not significantly influenced by triceps focus although borderline significant, with a mean difference of 5% nEMG (95% CI 0-10; Cohen's d 0.30). However, years of training experience was positively associated with the ability to selectively activate the triceps (β = 0.41, P = 0.04), but not the pectoralis. Bench press 1RM was not significantly associated with the ability to selectively activate the muscles. Pectoralis activity can be increased when focusing on using this muscle during push-ups, whereas the ability to do this for the triceps is dependent on years of training experience. Maximal muscle strength does not appear to be a decisive factor for the ability to selectively activate these muscles.

Using the Inflection Points and Rates of Growth and Decay to Predict Levels of Solar Activity

NASA Technical Reports Server (NTRS)

Wilson, Robert M.; Hathaway, David H.

2008-01-01

The ascending and descending inflection points and rates of growth and decay at specific times during the sunspot cycle are examined as predictors for future activity. On average, the ascending inflection point occurs about 1-2 yr after sunspot minimum amplitude (Rm) and the descending inflection point occurs about 6-7 yr after Rm. The ascending inflection point and the inferred slope (including the 12-mo moving average (12-mma) of (Delta)R (the month-to-month change in the smoothed monthly mean sunspot number (R)) at the ascending inflection point provide strong indications as to the expected size of the ongoing cycle s sunspot maximum amplitude (RM), while the descending inflection point appears to provide an indication as to the expected length of the ongoing cycle. The value of the 12-mma of (Delta)R at elapsed time T = 27 mo past the epoch of RM (E(RM)) seems to provide a strong indication as to the expected size of Rm for the following cycle. The expected Rm for cycle 24 is 7.6 +/- 4.4 (the 90-percent prediction interval), occurring before September 2008. Evidence is also presented for secular rises in selected cycle-related parameters and for preferential grouping of sunspot cycles by amplitude and/or period.

The validity and reliability of a customized rigid supportive harness during Smith machine back squat exercise.

PubMed

Scott, Brendan R; Dascombe, Ben J; Delaney, Jace A; Elsworthy, Nathan; Lockie, Robert G; Sculley, Dean V; Slattery, Katie M

2014-03-01

Although the back squat exercise is commonly prescribed to both athletic and clinical populations, individuals with restricted glenohumeral mobility may be unable to safely support the bar on the upper trapezius using their hands. The aims of this study were to investigate the validity and reliability of a back squat variation using a rigid supportive harness that does not require unrestricted glenohumeral mobility for quantifying 1 repetition maximum (1RM). Thirteen young men (age = 25.3 ± 4.5 years, height = 179.2 ± 6.9 cm, and body mass = 86.6 ± 12.0 kg) with at least 2 years resistance training experience volunteered to participate in the study. Subjects reported to the lab on 3 occasions, each separated by 1 week. During testing sessions, subjects were assessed for 1RM using the traditional back squat (session 1) and harness back squat (HBS; sessions 2 and 3) exercises. Mean 1RM for the traditional back squat, and 2 testing sessions of the HBS (HBS1 and HBS2) were 148.4 ± 25.0 kg, 152.5 ± 25.7 kg, and 150.4 ± 22.6 kg, respectively. Back squat and mean HBS 1RM scores were very strongly correlated (r = 0.96; p < 0.001). There were no significant differences in 1RM scores between the 3 trials. The test-retest 1RM scores with the HBS demonstrated high reliability, with an intraclass correlation coefficient of 0.98 (95% confidence interval [CI] = 0.93-0.99), and a coefficient of variation of 2.6% (95% CI = 1.9-4.3). Taken together, these data suggest that the HBS exercise is a valid and reliable method for assessing 1RM in young men with previous resistance training experience and may be useful for individuals with restricted glenohumeral mobility.

Relationships between salivary testosterone and cortisol concentrations and training performance in Olympic weightlifters.

PubMed

Crewther, B T; Christian, Cook

2010-09-01

This study examined the relationships between salivary testosterone (Sal-T) and cortisol (Sal-C) concentrations and training performance in Olympic weightlifters. Four male and four female Olympic weightlifters each provided saliva samples before and after four workouts during a four-week training period. Training involved the same three exercises; snatch, clean and jerk, and front squat with the one repetition maximum (1RM) calculated for each exercise during each workout. Significant (P < 0.05-0.01) training improvements in 1RM performance (4.0-5.2%) were noted during the snatch and clean and jerk exercises, along with the Olympic total lift. For male participants only, the pre-workout concentrations of Sal T were significantly (P < 0.05-0.01) correlated with the snatch (r = 0.70) and clean and jerk 1RM (r = 0.62), and the Olympic total lift (r = 0.66). A short period of training improved the 1RM performance of Olympic weightlifters in two exercises (snatch and clean and jerk) and the Olympic total. For male participants, their Sal-T concentrations before each workout was also related to 1RM performance during these exercises, thereby highlighting one possible short-term causative mechanism. Limitations of this study include the short duration of hormonal monitoring, the limited number of workouts assessed and the small number of participants recruited. Also, correlations between the outcome variables still only reflect casual associations.

Skeletal Adaptations to Different Levels of Eccentric Resistance Following Eight Weeks of Training

NASA Technical Reports Server (NTRS)

English, Kirk L.; Loehr, James A.; Lee, Stuart M. C.; Maddocks, Mary J.; Laughlin, Mitzi S.; Hagan, R. Donald

2007-01-01

Coupled concentric-eccentric resistive exercise maintains bone mineral density (BMD) during bed rest and aging. PURPOSE: We hypothesized that 8 wks of lower body resistive exercise training with higher ratios of eccentric to concentric loading would enhance hip and lumbar BMD. METHODS: Forty untrained male volunteers (34.9+/-7.0 yrs, 80.9+/-9.8 kg, 178.2+/-7.1 cm; mean+/-SD) were matched for leg press (LP) 1-Repetition Maximum (1-RM) strength and randomly assigned to one of 5 training groups. Concentric load (% 1-RM) was constant across groups, but each group trained with different levels of eccentric load (0, 33, 66, 100, or 138% of concentric) for all training sessions. Subjects performed a periodized supine LP and heel raise (HR) training program 3 d wk-1 for 8 wks using a modified Agaton Fitness System (Agaton Fitness AB, Boden, Sweden). Hip and lumbar BMD (g/sq cm) was measured in triplicate pre- and post-training using DXA (Hologic Discovery ). Pre- and post-training means were compared using the appropriate ANOVA and Tukey's post hoc tests. Within group pre- to post-training BMD was compared using paired t-tests with a Bonferroni adjustment. RESULTS: There was a main effect of training on L1, L2, L3, L4, total lumbar, and greater trochanter BMD, but there were no differences between groups. CONCLUSION: Eights wks of lower body resistive exercise increased greater trochanter and lumbar BMD. Inability to detect group differences may have been influenced by a potentially osteogenic vibration associated with device operation in the 0, 33, and 66% groups.

Biological reference materials for extracellular vesicle studies.

PubMed

Valkonen, S; van der Pol, E; Böing, A; Yuana, Y; Yliperttula, M; Nieuwland, R; Laitinen, S; Siljander, P R M

2017-02-15

Extracellular vesicles (EVs) mediate normal physiological homeostasis and pathological processes by facilitating intercellular communication. Research of EVs in basic science and clinical settings requires both methodological standardization and development of reference materials (RM). Here, we show insights and results of biological RM development for EV studies. We used a three-step approach to find and develop a biological RM. First, a literature search was done to find candidates for biological RMs. Second, a questionnaire was sent to EV researchers querying the preferences for RM and their use. Third, a biological RM was selected, developed, characterized, and evaluated. The responses to the survey demonstrated a clear and recognized need for RM optimized for the calibration of EV measurements. Based on the literature, naturally occurring and produced biological RM, such as virus particles and liposomes, were proposed as RM. However, none of these candidate RMs have properties completely matching those of EVs, such as size and refractive index distribution. Therefore, we evaluated the use of nanoerythrosomes (NanoE), vesicles produced from erythrocytes, as a potential biological RM. The strength of NanoE is their resemblance to EVs. Compared to the erythrocyte-derived EVs (eryEVs), NanoE have similar morphology, a similar refractive index (1.37), larger diameter (70% of the NanoE are over 200nm), and increased positive staining for CD235a and lipids (Di-8-ANEPPS) (58% and 67% in NanoE vs. 21% and 45% in eryEVs, respectively). Altogether, our results highlight the general need to develop and validate new RM with similar physical and biochemical properties as EVs to standardize EV measurements between instruments and laboratories. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Return to work of cancer patients after a multidisciplinary intervention including occupational counselling and physical exercise in cancer patients: a prospective study in the Netherlands.

PubMed

Leensen, Monique C J; Groeneveld, Iris F; Heide, Iris van der; Rejda, Tomas; van Veldhoven, Peter L J; Berkel, Sietske van; Snoek, Aernout; Harten, Wim van; Frings-Dresen, Monique H W; de Boer, Angela G E M

2017-06-15

To support return to work (RTW) among cancer patients, a multidisciplinary rehabilitation programme was developed which combined occupational counselling with a supervised physical exercise programme during chemotherapy. The aim was to investigate RTW rates of cancer patients and to evaluate changes in work-related quality of life and physical outcomes. Longitudinal prospective intervention study using a one-group design. Two hospitals in the Netherlands. Of the eligible patients, 56% participated; 93 patients with a primary diagnosis of cancer receiving chemotherapy and on sick leave were included. Patients completed questionnaires on RTW, the importance of work, work ability (WAI), RTW self-efficacy, fatigue (MFI), and quality of life (EORTC QLQ C-30) at baseline and 6, 12 and 18 months follow-up. Before and after the exercise programme 1-repetition maximum (1RM) muscle strength and cardiorespiratory fitness (VO 2 peak) were assessed. Six months after the start of a multidisciplinary rehabilitation programme that combined occupational counselling with a supervised physical exercise programme, 59% of the cancer patients returned to work, 86% at 12 months and 83% at 18 months. In addition, significant improvements (p<0.05) in the importance of work, work ability, RTW self-efficacy, and quality of life were observed, whereas fatigue levels were significantly reduced. After completing the exercise programme, 1RM muscle strength was significantly increased but there was no improvement in VO 2 peak level. RTW rates of cancer patients were high after completion of the multidisciplinary rehabilitation programme. A multidisciplinary rehabilitation programme which combines occupational counselling with a supervised physical exercise programme is likely to result in RTW, reduced fatigue and increased importance of work, work ability, and quality of life. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Return to work of cancer patients after a multidisciplinary intervention including occupational counselling and physical exercise in cancer patients: a prospective study in the Netherlands

PubMed Central

Leensen, Monique C J; Groeneveld, Iris F; van der Heide, Iris; Rejda, Tomas; van Veldhoven, Peter L J; van Berkel, Sietske; Snoek, Aernout; van Harten, Wim; Frings-Dresen, Monique H W; de Boer, Angela G E M

2017-01-01

Objectives To support return to work (RTW) among cancer patients, a multidisciplinary rehabilitation programme was developed which combined occupational counselling with a supervised physical exercise programme during chemotherapy. The aim was to investigate RTW rates of cancer patients and to evaluate changes in work-related quality of life and physical outcomes. Design Longitudinal prospective intervention study using a one-group design. Setting Two hospitals in the Netherlands. Participants Of the eligible patients, 56% participated; 93 patients with a primary diagnosis of cancer receiving chemotherapy and on sick leave were included. Patients completed questionnaires on RTW, the importance of work, work ability (WAI), RTW self-efficacy, fatigue (MFI), and quality of life (EORTC QLQ C-30) at baseline and 6, 12 and 18 months follow-up. Before and after the exercise programme 1-repetition maximum (1RM) muscle strength and cardiorespiratory fitness (VO2 peak) were assessed. Results Six months after the start of a multidisciplinary rehabilitation programme that combined occupational counselling with a supervised physical exercise programme, 59% of the cancer patients returned to work, 86% at 12 months and 83% at 18 months. In addition, significant improvements (p<0.05) in the importance of work, work ability, RTW self-efficacy, and quality of life were observed, whereas fatigue levels were significantly reduced. After completing the exercise programme, 1RM muscle strength was significantly increased but there was no improvement in VO2 peak level. Conclusions RTW rates of cancer patients were high after completion of the multidisciplinary rehabilitation programme. A multidisciplinary rehabilitation programme which combines occupational counselling with a supervised physical exercise programme is likely to result in RTW, reduced fatigue and increased importance of work, work ability, and quality of life. PMID:28619770

Knee Joint Kinetics in Relation to Commonly Prescribed Squat Loads and Depths

PubMed Central

Cotter, Joshua A.; Chaudhari, Ait M.; Jamison, Steve T.; Devor, Steven T.

2014-01-01

Controversy exists regarding the safety and performance benefits of performing the squat exercise to depths beyond 90° of knee flexion. Our aim was to compare the net peak external knee flexion moments (pEKFM) experienced over typical ranges of squat loads and depths. Sixteen recreationally trained males (n = 16; 22.7 ± 1.1 yrs; 85.4 ± 2.1 kg; 177.6 ± 0.96 cm; mean ± SEM) with no previous lower limb surgeries or other orthopedic issues and at least one year of consistent resistance training experience while utilizing the squat exercise performed single repetition squat trials in a random order at squat depths of above parallel, parallel, and below parallel. Less than one week before testing, one repetition maximum (1RM) values were found for each squat depth. Subsequent testing required subjects to perform squats at the three depths with three different loads: unloaded, 50% 1RM, and 85% 1RM (nine total trials). Force platform and kinematic data were collected to calculate pEKFM. To assess differences among loads and depths, a two-factor (load and depth) repeated-measures ANOVA with significance set at the P < 0.05 level was used. Squat 1RM significantly decreased 13.6% from the above parallel to parallel squat and another 3.6% from the parallel to the below parallel squat (P < 0.05). Net peak external knee flexion moments significantly increased as both squat depth and load were increased (P ≤ 0.02). Slopes of pEKFM were greater from unloaded to 50% 1RM than when progressing from 50% to 85% 1RM (P < 0.001). The results suggest that that typical decreases in squat loads used with increasing depths are not enough to offset increases in pEKFM. PMID:23085977

CHANGES IN MUSCLE DAMAGE MARKERS IN FEMALE BASKETBALL PLAYERS

PubMed Central

Moreira, A.; Nosaka, K.; Nunes, J.A.; Viveiros, L.; Jamurtas, A.Z.

2014-01-01

The aim of the present study was to investigate changes in muscle soreness, blood muscle damage markers, muscle strength and agility following an official basketball match. Eleven elite female professional basketball players (27.4 ± 4.8 years, 179.5 ± 5.5 cm, 72.0 ± 7.8 kg) of a team participated in this study. The official match was the seventh match of the season in the first phase of the Brazilian National Female Basketball Championship. Muscle soreness, plasma creatine kinase activity (CK), and myoglobin concentration (Mb) were determined before and after the match (post-match, 24 and 48 hours after the match). The 1RM strength for bench press and leg press, and the agility T test were assessed before and at 24 and 48 hours after the match. Significant increases in muscle soreness, CK and Mb were observed at 24 and 48 hours post-match (p<0.05). No significant changes in the 1RM strength and T test were detected during recovery (24 and 48 hours after the match). These results suggest that a basketball match induced limited muscle damage with minimal effect on performance during recovery. The small increase in muscle damage markers following a basketball match did not affect strength and agility performance. PMID:24917683

Changes in muscle damage markers in female basketball players.

PubMed

Moreira, A; Nosaka, K; Nunes, J A; Viveiros, L; Jamurtas, A Z; Aoki, M S

2014-03-01

The aim of the present study was to investigate changes in muscle soreness, blood muscle damage markers, muscle strength and agility following an official basketball match. Eleven elite female professional basketball players (27.4 ± 4.8 years, 179.5 ± 5.5 cm, 72.0 ± 7.8 kg) of a team participated in this study. The official match was the seventh match of the season in the first phase of the Brazilian National Female Basketball Championship. Muscle soreness, plasma creatine kinase activity (CK), and myoglobin concentration (Mb) were determined before and after the match (post-match, 24 and 48 hours after the match). The 1RM strength for bench press and leg press, and the agility T test were assessed before and at 24 and 48 hours after the match. Significant increases in muscle soreness, CK and Mb were observed at 24 and 48 hours post-match (p<0.05). No significant changes in the 1RM strength and T test were detected during recovery (24 and 48 hours after the match). These results suggest that a basketball match induced limited muscle damage with minimal effect on performance during recovery. The small increase in muscle damage markers following a basketball match did not affect strength and agility performance.

Comparison of shuttle and straight repeated-sprint ability tests and their relationship to anthropometrics and explosive muscular performance of lower limb in elite handball players.

PubMed

Hermassi, Souhail; Schwesig, René; Wollny, Rainer; Fieseler, Georg; van den Tillaar, Roland; Fernandez-Fernandez, Jaime; Shephard, Roy J; Chelly, Mohamed S

2017-06-21

This study assessed inter-relationships between shuttle and straight repeated-sprint ability tests and the relationship of each measure to anthropometric and explosive lower limb performance data in elite handball players. Twenty-two elite male handball players (18.9 ± 0.2 years; body mass: 83.3 ± 1.1 kg, height: 1.79 ± 2.30 m, body fat: 12.8 ± 0.2%) completed tests that included a lower limb force-velocity test of peak power (Wpeak), jumping ability (squat and counter-movement jumps; SJ, CMJ), 1 repetition maximum (1-RM) half back squat, average sprint velocity over 5 m (V-5 m), peak velocity between 25-30 m (Vmax), and Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1), and anthropometric determinations of cross-sectional areas and muscle volumes for leg and thigh muscles. Data were compared with performance on 2 repeated sprint tests; the straight test [6 × 30 m (RSA30)] and the intermittent test [6 x (2 x 15 m) shuttle sprints (RSA15)]. V-5 m; 1-RM; and thigh and leg muscle cross-sectional areas and volumes showed relevant relationships to the shuttle RSA test (r2≥0.5). The Yo-Yo IR1 explained the largest percentage of variance in RSA15 total time (60%), and V-5 m also explained 56% of the variance in RSA15 total time. RSA15% fatigue was only related to 1-RM (explained variance: 58%), and the RSA30 test showed no useful correlations with any of the investigated predictors. Multiple-regression analyses using all physical tests explained 91% of the variance in RSA15 total time (p<0.001). The volume of the leg muscles seems important to power production and repeated sprints over distances of 15 m or less. RSA15 is related to muscular power, maximal strength, speed and endurance performance; however, the straight repeated sprint ability test is not, and thus does not seem relevant for the testing of handball players.

Full Range of Motion Induces Greater Muscle Damage Than Partial Range of Motion in Elbow Flexion Exercise With Free Weights.

PubMed

Baroni, Bruno M; Pompermayer, Marcelo G; Cini, Anelize; Peruzzolo, Amanda S; Radaelli, Régis; Brusco, Clarissa M; Pinto, Ronei S

2017-08-01

Baroni, BM, Pompermayer, MG, Cini, A, Peruzzolo, AS, Radaelli, R, Brusco, CM, and Pinto, RS. Full range of motion induces greater muscle damage than partial range of motion in elbow flexion exercise with free weights. J Strength Cond Res 31(8): 2223-2230, 2017-Load and range of motion (ROM) applied in resistance training (RT) affect the muscle damage magnitude and the recovery time-course. Because exercises performed with partial ROM allow a higher load compared with those with full ROM, this study investigated the acute effect of a traditional RT exercise using full ROM or partial ROM on muscle damage markers. Fourteen healthy men performed 4 sets of 10 concentric-eccentric repetitions of unilateral elbow flexion on the Scott bench. Arms were randomly assigned to partial-ROM (50-100°) and full-ROM (0-130°) conditions, and load was determined as 80% of 1 repetition maximum (1RM) in the full- and partial-ROM tests. Muscle damage markers were assessed preexercise, immediately, and 24, 48, and 72 hours after exercise. Primary outcomes were peak torque, muscle soreness during palpation and elbow extension, arm circumference, and joint ROM. The load lifted in the partial-ROM condition (1RM = 19.1 ± 3.0 kg) was 40 ± 18% higher compared with the full-ROM condition (1RM = 13.7 ± 2.2 kg). Seventy-two hours after exercise, the full-ROM condition led to significant higher soreness sensation during elbow extension (1.3-4.1 cm vs. 1.0-1.9 cm) and smaller ROM values (97.5-106.1° vs. 103.6-115.7°). Peak torque, soreness from palpation, and arm circumference were statistically similar between conditions, although mean values in all time points of these outcomes have suggested more expressive muscle damage for the full-ROM condition. In conclusion, elbow flexion exercise with full ROM seems to induce greater muscle damage than partial-ROM exercises, even though higher absolute load was achieved with partial ROM.

Postactivation potentiation: effect of various recovery intervals on bench press power performance.

PubMed

Ferreira, Sandra Lívia de Assis; Panissa, Valéria Leme Gonçalves; Miarka, Bianca; Franchini, Emerson

2012-03-01

Postactivation potentiation (PAP) is a strategy used to improve performance in power activities. The aim of this study was to determine if power during bench press exercise was increased when preceded by 1 repetition maximum (1RM) in the same exercise and to determine which time interval could optimize PAP response. For this, 11 healthy male subjects (age, 25 ± 4 years; height, 178 ± 6 cm; body mass, 74 ± 8 kg; bench press 1RM, 76 ± 19 kg) underwent 6 sessions. Two control sessions were conducted to determine both bench press 1RM and power (6 repetitions at 50% 1RM). The 4 experimental sessions were composed of a 1RM exercise followed by power sets with different recovery intervals (1, 3, 5, and 7 minutes), performed on different days, and determined randomly. Power values were measured via Peak Power equipment (Cefise, Nova Odessa, São Paulo, Brazil). The conditions were compared using an analysis of variance with repeated measures, followed by a Tukey test. The significance level was set at p < 0.05. There was a significant increase in PAP in concentric contractions after 7 minutes of recovery compared with the control and 1-minute recovery conditions (p < 0.05). Our results indicated that 7 minutes of recovery has generated an increase in PAP in bench press and that such a strategy could be applied as an interesting alternative to enhance the performance in tasks aimed at increasing upper-body power performance.

Factors and values of willingness to pay for improved construction waste management--a perspective of Malaysian contractors.

PubMed

Begum, Rawshan Ara; Siwar, Chamhuri; Pereira, Joy Jacqueline; Jaafar, Abdul Hamid

2007-01-01

Malaysia is facing an increase in the generation of waste and of accompanying problems with the disposal of this waste. In the last two decades, extensive building and infrastructure development projects have led to an increase in the generation of construction waste material. The construction industry has a substantial impact on the environment, and its environmental effects are in direct relation to the quality and quantity of the waste it generates. This paper discusses general characteristics of the construction contractors, the contractors' willingness to pay (WTP) for improved construction waste management, determining factors which affect the amount of their willingness to pay, and suggestions and policy implications in the perspective of construction waste management in Malaysia. The data in this study is based on contractors registered with the construction industry development board (CIDB) of Malaysia. Employing the open ended contingent valuation method, the study assessed the contractors' average maximum WTP for improved construction waste management to be RM69.88 (1US$=3.6 RM) per tonne of waste. The result shows that the average maximum WTP is higher for large contractors than for medium and small contractors. The highest average maximum WTP value is RM88.00 for Group A (large contractors) RM78.25 for Group B (medium-size contractors) and RM55.80 for Group C (small contractors). One of the contributions of this study is to highlight the difference of CIDB registration grade in the WTP for improved construction waste management. It is found that contractors' WTP for improved waste collection and disposal services increases with the increase in contractors' current paid up capital. The identified factors and determinants of the WTP will assist the formulation of appropriate policies in addressing the construction waste problem in Malaysia and indirectly improve the quality of construction in the country.

Peak power, force, and velocity during jump squats in professional rugby players.

PubMed

Turner, Anthony P; Unholz, Cedric N; Potts, Neill; Coleman, Simon G S

2012-06-01

Training at the optimal load for peak power output (PPO) has been proposed as a method for enhancing power output, although others argue that the force, velocity, and PPO are of interest across the full range of loads. The aim of this study was to examine the influence of load on PPO, peak barbell velocity (BV), and peak vertical ground reaction force (VGRF) during the jump squat (JS) in a group of professional rugby players. Eleven male professional rugby players (age, 26 ± 3 years; height, 1.83 ± 6.12 m; mass, 97.3 ± 11.6 kg) performed loaded JS at loads of 20-100% of 1 repetition maximum (1RM) JS. A force plate and linear position transducer, with a mechanical braking unit, were used to measure PPO, VGRF, and BV. Load had very large significant effects on PPO (p < 0.001, partial η² = 0.915); peak VGRF (p < 0.001, partial η² = 0.854); and peak BV (p < 0.001, partial η² = 0.973). The PPO and peak BV were the highest at 20% 1RM, though PPO was not significantly greater than that at 30% 1RM. The peak VGRF was significantly greater at 1RM than all other loads, with no significant difference between 20 and 60% 1RM. In resistance trained professional rugby players, the optimal load for eliciting PPO during the loaded JS in the range measured occurs at 20% 1RM JS, with decreases in PPO and BV, and increases in VGRF, as the load is increased, although greater PPO likely occurs without any additional load.

Arsenic sorption by red mud-modified biochar produced from rice straw.

PubMed

Wu, Chuan; Huang, Liu; Xue, Sheng-Guo; Huang, Yu-Ying; Hartley, William; Cui, Meng-Qian; Wong, Ming-Hung

2017-08-01

Red mud-modified biochar (RM-BC) has been produced to be utilized as a novel adsorbent to remove As because it can effectively combine the beneficial features of red mud (rich metal oxide composition and porous structure) and biochar (large surface area and porous structure properties). SEM-EDS and XRD analyses demonstrated that red mud had loaded successfully on the surface of biochar. With the increasing of pH in solution, arsenate (As(V)) adsorption on RM-BC decreased while arsenite (As(III)) increased. Arsenate adsorption kinetics process on RM-BC fitted the pseudo-second-order model, while that of As(III) favored the Elovich model. All sorption isotherms produced superior fits with the Langmuir model. RM-BC exhibited improved As removal capabilities, with a maximum adsorption capacity (Q max ) for As(V) of 5923 μg g -1 , approximately ten times greater than that of the untreated BC (552.0 μg g -1 ). Furthermore, it has been indicated that the adsorption of As(V) on RM-BC may be strongly associated with iron oxides (hematite and magnetite) and aluminum oxides (gibbsite) by X-ray absorption near-edge spectroscopy (XANES), which was possibly because of surface complexation and electrostatic interactions. RM-BC may be used as a valuable adsorbent for removing As in the environment due to the waste materials being relatively abundant.

Long-term exercise training in persons with spinal cord injury: effects on strength, arm ergometry performance and psychological well-being.

PubMed

Hicks, A L; Martin, K A; Ditor, D S; Latimer, A E; Craven, C; Bugaresti, J; McCartney, N

2003-01-01

Randomized controlled trial of exercise training in persons with spinal cord injury. The purpose of this study was to examine the effects of 9 months of twice-weekly exercise training on strength, arm ergometry performance, and indices of psychological well-being and quality of life. Centre for Health Promotion and Rehabilitation, McMaster University, Hamilton, Ontario, Canada. Thirty-four men and women (aged 19-65 years) with traumatic spinal cord injury (C4-L1; ASIA A-D) of 1-24 years duration volunteered to participate, and were randomized into exercise (EX; n=21) and control (CON; n=13) groups. Twenty-three subjects (11 EX; 12 CON) successfully completed the 9-month study. Subjects were assessed for one repetition maximum (1RM) strength, arm ergometry performance, and several indices of quality of life and psychological well-being at baseline, 3, 6, and 9 months. At baseline, there were no significant differences between groups in age, submaximal arm ergometry performance, muscle strength, or psychological well-being. Following training, the EX group had significant increases in submaximal arm ergometry power output (81%; P<0.05), and significant increases in upper body muscle strength (19-34%; P<0.05); no significant changes occurred in CON. Participants in EX reported significantly less pain, stress and depression after training, and scored higher than CON in indices of satisfaction with physical function, level of perceived health and overall quality of life (P<0.05). Exercise adherence (per cent of prescribed sessions attended) in those subjects who completed the 9 months of training was 82.5%. These results demonstrate that long-term twice-weekly exercise training in this population is feasible, and results in significant gains in both physical and psychological well-being.

Impact of 10-Minute Interval Roller Massage on Performance and Active Range of Motion.

PubMed

Hodgson, D D; Quigley, P J; Whitten, J H D; Reid, J C; Behm, David G

2017-11-16

Hodgson, DD, Quigley, PJ, Whitten, JHD, Reid, JC, and Behm, DG. Impact of 10-minute interval roller massage on performance and active range of motion. J Strength Cond Res XX(X): 000-000, 2017-Roller massage (RM) has been shown to increase range of motion (ROM) without subsequent performance deficits. However, prolonged static stretching (SS) can induce performance impairments. The objective of this study was to examine the effects of combining SS and RM with and without subsequent RM on ROM and neuromuscular performance. Subjects (n = 12) participated in 5 sessions: (a) SS only (SS_rest), (b) SS + RM (SS + RM_rest), (c) SS with RM at 10 and 20 minutes after stretch (SS_RM), (d) SS + RM with RM at 10 and 20 minutes after stretch (SS + RM_RM), and (e) control. For the SS conditions, the quadriceps and hamstrings received passive SS for 2 × 30 seconds each. For the SS + RM conditions, SS was applied to the quadriceps and hamstrings for 30 seconds each, and RM was performed for 30 seconds per muscle. SS_RM and SS + RM_RM conditions received an additional 30-second RM at 10 and 20 minutes after warm-up, whereas sessions without additional RM rested for the same duration. Testing measures included hip flexion (HF) and knee flexion (KF) active and passive ROM, hurdle jump height and contact time, countermovement jump height, and maximal voluntary isometric contraction force. Initial KF and HF ROM improvements provided by SS_RM and SS + RM_RM were sustained up to 30 minutes after intervention. Furthermore, SS_RM exhibited greater ROM compared with sessions lacking additional RM in active and passive HF as well as active and passive KF. Similarly, SS + RM_RM elicited greater KF and HF ROM improvements than SS_rest. In conclusion, active KF and HF ROM improvements were prolonged by additional RM, whereas neuromuscular performance remained relatively unaffected.

Relationship between Physiological Off-Ice Testing, On-Ice Skating, and Game Performance in Division I Women's Ice Hockey Players.

PubMed

Boland, Michelle; Miele, Emily M; Delude, Katie

2017-10-07

The purpose was to identify off-ice testing variables that correlate to skating and game performance in Division I collegiate women ice hockey players. Twenty female, forward and defensive players (19.95 ± 1.35 yr) were assessed for weight, height, percent fat mass (%FAT), bone mineral density, predicted one repetition maximum (RM) absolute and relative (REL%) bench press (BP) and hex bar deadlift (HDL), lower body explosive power, anaerobic power, countermovement vertical jump (CMJ), maximum inspiratory pressure (MIP), and on-ice repeated skate sprint (RSS) performance. The on-ice RSS test included 6 timed 85.6 m sprints with participants wearing full hockey equipment; fastest time (FT), average time (AT) and fatigue index (FI) for the first length skate (FLS; 10 m) and total length skate (TLS; 85.6 m) were used for analysis. Game performance was evaluated with game statistics: goals, assists, points, plus-minus, and shots on goal (SOG). Correlation coefficients were used to determine relationships. Percent fat mass was positively correlated (p < 0.05) with FLS-FI and TLS-AT; TLS-FT was negatively correlated with REL%HDL; BP-RM was negatively correlated with FLS-FT and FLS-AT; MIP positively correlated with assists, points, and SOG; FLS-AT negatively correlated with assists. Game performance in women ice hockey players may be enhanced by greater MIP, repeat acceleration ability, and mode-specific training. Faster skating times were associated with lower %FAT. Skating performance in women ice hockey players may be enhanced by improving body composition, anaerobic power, and both lower and upper body strength in off-ice training.

Short rest interval lengths between sets optimally enhance body composition and performance with 8 weeks of strength resistance training in older men.

PubMed

Villanueva, Matthew G; Lane, Christianne Joy; Schroeder, E Todd

2015-02-01

To determine if 8 weeks of periodized strength resistance training (RT) utilizing relatively short rest interval lengths (RI) in between sets (SS) would induce greater improvements in body composition and muscular performance, compared to the same RT program utilizing extended RI (SL). 22 male volunteers (SS: n = 11, 65.6 ± 3.4 years; SL: n = 11, 70.3 ± 4.9 years) were assigned to one of two strength RT groups, following 4 weeks of periodized hypertrophic RT (PHRT): strength RT with 60-s RI (SS) or strength RT with 4-min RI (SL). Prior to randomization, all 22 study participants trained 3 days/week, for 4 weeks, targeting hypertrophy; from week 4 to week 12, SS and SL followed the same periodized strength RT program for 8 weeks, with RI the only difference in their RT prescription. Following PHRT, all study participants experienced increases in lean body mass (LBM) (p < 0.01), upper and lower body strength (p < 0.001), and dynamic power (p < 0.001), as well as decreases in percentage body fat (p < 0.05). Across the 8-week strength RT phase, SS experienced significantly greater increases in LBM (p = 0.001), flat machine bench press 1-RM (p < 0.001), bilateral leg press 1-RM (p < 0.001), narrow/neutral grip lat pulldown (p < 0.01), and Margaria stair-climbing power (p < 0.001), compared to SL. This study suggests 8 weeks of periodized high-intensity strength RT with shortened RI induces significantly greater enhancements in body composition, muscular performance, and functional performance, compared to the same RT prescription with extended RI, in older men. Applied professionals may optimize certain RT-induced adaptations, by incorporating shortened RI.

Bench press exercise: the key points.

PubMed

Padulo, J; Laffaye, G; Chaouachi, A; Chamari, K

2015-06-01

The bench press exercise (BPE) is receiving increasing interest as a field testing, training/therapeutic modality to improve neuromuscular performance or to increase bone mass density. Several studies have been performed using BPE as a standard for increasing upper-limb strength. For this purpose, the position of the bar, the loads, the sets, the number of repetitions, the recovery time in-between sets, the movement speed, the muscular work and the use of the determination of the one repetition maximum (1-RM) are the classical tools investigated in the literature that have been shown to affect the BPE effect on neuromuscular. The goal of the present short review is to make a picture of the current knowledge on the bench press exercise, which could be very helpful for a better understanding of this standard movement and its effects. Based on the related literature, several recommendations on these key points are presented here.

Dynamic versus isometric electromechanical delay in non-fatigued and fatigued muscle: A combined electromyographic, mechanomyographic, and force approach.

PubMed

Smith, Cory M; Housh, Terry J; Hill, Ethan C; Johnson, Glen O; Schmidt, Richard J

2017-04-01

This study used a combined electromyographic, mechanomyographic, and force approach to identify electromechanical delay (EMD) from the onsets of the electromyographic to force signals (EMD E-F ), onsets of the electromyographic to mechanomyogrpahic signals (EMD E-M ), and onsets of mechanomyographic to force signals (EMD M-F ). The purposes of the current study were to examine: (1) the differences in EMD E-F , EMD E-M , and EMD M-F from the vastus lateralis during maximal, voluntary dynamic (1 repetition maximum [1-RM]) and isometric (maximal voluntary isometric contraction [MVIC]) muscle actions; and (2) the effects of fatigue on EMD E-F , EMD M-F , and EMD E-M . Ten men performed pretest and posttest 1-RM and MVIC leg extension muscle actions. The fatiguing workbout consisted of 70% 1-RM dynamic constant external resistance leg extension muscle actions to failure. The results indicated that there were no significant differences between 1-RM and MVIC EMD E-F , EMD E-M , or EMD M-F. There were, however, significant fatigue-induced increases in EMD E-F (94% and 63%), EMD E-M (107%), and EMD M-F (63%) for both the 1-RM and MVIC measurements. Therefore, these findings demonstrated the effects of fatigue on EMD measures and supported comparisons among studies which examined dynamic or isometric EMD measures from the vastus lateralis using a combined electromyographic, mechanomyographic, and force approach. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of training level and blood flow restriction on thermal parameters: Preliminary study

NASA Astrophysics Data System (ADS)

Sampaio, Lucas; Bezerra, Ewertton; Paladino, Kayo; dos Santos, João Otacílio Libardoni; Priego Quesada, Jose I.; Rossato, Mateus

2016-11-01

Training with blood flow restriction could lead to an effect on skin temperature. Additionally, this effect could be higher in people with lower physical fitness level due to their lower capacity of heat loss. The aim of this preliminary study was therefore to evaluate the effects of training experience on the acute and chronic thermal skin responses after performing exercise with and without blood flow restriction. The study included ten men, of these, five were trained. All subjects performed tests and re-tests for maximum strength (1 repetition maximum) through unilateral leg extensions (right thigh at 45 ± 6.7 kg and left thigh at 45.5 ± 8.1 kg, p > 0.05). The protocol consisted of four sets to concentric failure, with one-minute rest intervals between sets at an intensity corresponding to 40% of 1 RM. There were 7-day intervals between experimental sessions (150 mmHg versus unrestricted flow restriction). The thermal images were made before the protocol (pre), immediately after the end of the series (post), and 24 h afterward (post 24 h). When comparing temperature variation (Δ exercise and Δ 24 h) between groups, it was observed that the trained participants showed a greater drop in temperature 24 h after exercise with 150 mmHg restriction (confidence interval: 95% of Δ 24 h [-0.2 to -0.9 °C]) compared to untrained subjects (p = 0.006 and ES > 1.5, confidence interval: 95% Δ 24 h [-0.1 to 0.6 °C].) In conclusion, this preliminary study showed that training experience interferes with the chronic cutaneous thermal temperature of the anterior thigh when strength training associated with blood flow restriction 150 mmHg was performed.

Effects of Insect Protein Supplementation during Resistance Training on Changes in Muscle Mass and Strength in Young Men.

PubMed

Vangsoe, Mathias T; Joergensen, Malte S; Heckmann, Lars-Henrik L; Hansen, Mette

2018-03-10

During prolonged resistance training, protein supplementation is known to promote morphological changes; however, no previous training studies have tested the effect of insect protein isolate in a human trial. The aim of this study was to investigate the potential effect of insect protein as a dietary supplement to increase muscle hypertrophy and strength gains during prolonged resistance training in young men. Eighteen healthy young men performed resistance training four day/week for eight weeks. Subjects were block randomized into two groups consuming either an insect protein isolate or isocaloric carbohydrate supplementation within 1 h after training and pre-sleep on training days. Strength and body composition were measured before and after intervention to detect adaptions to the resistance training. Three-day weighed dietary records were completed before and during intervention. Fat- and bone- free mass (FBFM) improved significantly in both groups (Mean (95% confidence interval (CI))), control group (Con): (2.5 kg (1.5, 3.5) p < 0.01), protein group (Pro): (2.7 kg (1.6, 3.8) p < 0.01) from pre- to post-. Leg and bench press one repetition maximum (1 RM) improved by Con: (42.0 kg (32.0, 52.0) p < 0.01) and (13.8 kg (10.3, 17.2) p < 0.01), Pro: (36.6 kg (27.3, 45.8) p < 0.01) and (8.1 kg (4.5, 11.8) p < 0.01), respectively. No significant differences in body composition and muscle strength improvements were found between groups. In young healthy men, insect protein supplementation did not improve adaptations to eight weeks of resistance training in comparison to carbohydrate supplementation. A high habitual protein intake in both Con and Pro may partly explain our observation of no superior effect of insect protein supplementation.

Effects of Insect Protein Supplementation during Resistance Training on Changes in Muscle Mass and Strength in Young Men

PubMed Central

Vangsoe, Mathias T.; Joergensen, Malte S.

2018-01-01

During prolonged resistance training, protein supplementation is known to promote morphological changes; however, no previous training studies have tested the effect of insect protein isolate in a human trial. The aim of this study was to investigate the potential effect of insect protein as a dietary supplement to increase muscle hypertrophy and strength gains during prolonged resistance training in young men. Eighteen healthy young men performed resistance training four day/week for eight weeks. Subjects were block randomized into two groups consuming either an insect protein isolate or isocaloric carbohydrate supplementation within 1 h after training and pre-sleep on training days. Strength and body composition were measured before and after intervention to detect adaptions to the resistance training. Three-day weighed dietary records were completed before and during intervention. Fat- and bone- free mass (FBFM) improved significantly in both groups (Mean (95% confidence interval (CI))), control group (Con): (2.5 kg (1.5, 3.5) p < 0.01), protein group (Pro): (2.7 kg (1.6, 3.8) p < 0.01) from pre- to post- leg and bench press one repetition maximum (1 RM) improved by Con: (42.0 kg (32.0, 52.0) p < 0.01) and (13.8 kg (10.3, 17.2) p < 0.01), Pro: (36.6 kg (27.3, 45.8) p < 0.01) and (8.1 kg (4.5, 11.8) p < 0.01), respectively. No significant differences in body composition and muscle strength improvements were found between groups. In young healthy men, insect protein supplementation did not improve adaptations to eight weeks of resistance training in comparison to carbohydrate supplementation. A high habitual protein intake in both Con and Pro may partly explain our observation of no superior effect of insect protein supplementation. PMID:29534456

Effects of combined linear and nonlinear periodic training on physical fitness and competition times in finswimmers.

PubMed

Yu, Kyung-Hun; Suk, Min-Hwa; Kang, Shin-Woo; Shin, Yun-A

2014-10-01

The purpose of this study was to investigate the effect of combined linear and nonlinear periodic training on physical fitness and competition times in finswimmers. The linear resistance training model (6 days/week) and nonlinear underwater training (4 days/week) were applied to 12 finswimmers (age, 16.08± 1.44 yr; career, 3.78± 1.90 yr) for 12 weeks. Body composition measures included weight, body mass index (BMI), percent fat, and fat-free mass. Physical fitness measures included trunk flexion forward, trunk extension backward, sargent jump, 1-repetition-maximum (1 RM) squat, 1 RM dead lift, knee extension, knee flexion, trunk extension, trunk flexion, and competition times. Body composition and physical fitness were improved after the 12-week periodic training program. Weight, BMI, and percent fat were significantly decreased, and trunk flexion forward, trunk extension backward, sargent jump, 1 RM squat, 1 RM dead lift, and knee extension (right) were significantly increased. The 50- and 100-m times significantly decreased in all 12 athletes. After 12 weeks of training, all finswimmers who participated in this study improved their times in a public competition. These data indicate that combined linear and nonlinear periodic training enhanced the physical fitness and competition times in finswimmers.

Beating the Futures Conference Game.

ERIC Educational Resources Information Center

Simmonds, W. H. Clive

1983-01-01

Conference survival tips include: (1) noting the different kinds of speakers, their strengths and weaknesses; (2) discovering the reasons for often apparent cross-talk and misunderstanding; and (3) using the concept of futuring to gain ideas as to what can be done after the conference ends. (RM)

Effects of Phase Transformations and Dynamic Material Strength on Hydrodynamic Instability Evolution in Metals

NASA Astrophysics Data System (ADS)

Opie, Saul

Hydrodynamic phenomena such as the Rayleigh-Taylor (RT) and Richtmyer-Meshkov (RM) instabilities can be described by exponential/linear growth of surface perturbations at a bimaterial interface when subjected to constant/impulsive acceleration. A challenge in designing systems to mitigate or exploit these effects is the lack of accurate material models at large dynamic strain rates and pressures. In particular, little stress-strain constitutive information at large strain rates and pressures is available for transient material phases formed at high pressures, and the continuum effect the phase transformation process has on the instability evolution. In this work, a phase-aware isotropic strength model is developed and partially validated with a novel RM-based instability experiment in addition to existing data from the literature. With the validated material model additional simulations are performed to provide insight into to the role that robust material constitutive behavior (e.g., pressure, temperature, rate dependence) has on RM instability and how RM instability experiments can be used to characterize and validated expected material behavior. For phase aware materials, particularly iron in this work, the simulations predict a strong dependence on the Atwood number that single phase materials do not have. At Atwood numbers close to unity, and pressures in the high pressure stability region, the high pressure phase dominates the RM evolution. However, at Atwood numbers close to negative one, the RM evolution is only weakly affected by the high-pressure phase even for shocks well above the phase transformation threshold. In addition to RM evolution this work looks at the closely related shock front perturbation evolution. Existing analytical models for isentropic processes in gases and liquids are modified for metal equation of states and plastic behavior for the first time. It is found that the presence of a volume collapsing phase transformation with increased pressure causes shock front perturbations to decay sooner, while plastic strength has the opposite effect which is significantly different from the effect viscosity has. These results suggest additional experimental setups to validate material models, or relevant material parameters that can be optimized for system design objectives, e.g., minimize feed through perturbations in inertial confinement fusion capsules.

Shear Bond Strength of Metal Brackets to Zirconia Conditioned with Various Primer-Adhesive Systems

DTIC Science & Technology

2016-07-01

Reynolds, 1979 ). Bonding orthodontic brackets to ceramic restorative materials poses a unique challenge. Abu et al. measured the strength between...forth by Reynolds and 34 others (Reynolds, 1979 ). The pertinent question is the following: should brackets be chemically bonded to zirconia...conditioned with a new silane coupling agent. Eur J Orthod. 2013 Feb;35(1):103-9. 40 Giannini M, Soares CJ, de Carvalho RM. Ultimate tensile

Influence of Knee-to-Feet Jump Training on Vertical Jump and Hang Clean Performance.

PubMed

Stark, Laura; Pickett, Karla; Bird, Michael; King, Adam C

2016-11-01

Stark, L, Pickett, K, Bird, M, and King, AC. Influence of knee-to-feet jump training on vertical jump and hang clean performance. J Strength Cond Res 30(11): 3084-3089, 2016-From a motor learning perspective, the practice/training environment can result in positive, negative, or neutral transfer to the testing conditions. The purpose of this study was to examine the training effect of a novel movement (knee-to-feet [K2F] jumps) and whether a 6-week training program induced a positive transfer effect to other power-related movements (vertical jump and hang clean [HC]). Twenty-six intercollegiate athletes from power-emphasized sports were paired and counter-balanced into a control (i.e., maintained their respective sport-specific lifting regimen) or an experimental group (i.e., completed a 6-week progressive training program of K2F jumps in addition to respective lifting regimen). A pre- and posttest design was used to investigate the effect of training on K2F jump height and transfer effect to vertical jump height (VJH) and 2-repetition maximum (RM) HC performance. A significant increase in K2F jump height was found for the experimental group. Vertical jump height significantly increased from pre- to posttest but no group or interaction (group × time) effect was found, and there were nonsignificant differences for HC. Posttest data showed significant correlations between all pairs of the selected exercises with the highest correlation between K2F jump height and VJ H (R = 0.40) followed by VJH and 2RM HC (R = 0.38) and 2RM HC and K2F jump height (R = 0.23). The results suggest that K2F jump training induced the desired learning effect but was specific to the movement in that no effect of transfer occurred to the other power-related movements. This finding is value for strength and condition professionals who design training programs to enhance athletic performance.

U.S. Immigration Policy and the National Interest.

ERIC Educational Resources Information Center

Fauriol, Georges

1984-01-01

The national security of the United States depends upon its domestic strength and international stability. This strength requires an ability to control national borders, the maintenance of an independent foreign policy, a prosperous economy, and a cohesive domestic political environment. Uncontrolled migration is undermining this strength. (RM)

Reliability of the Load-Velocity Relationship Obtained Through Linear and Polynomial Regression Models to Predict the One-Repetition Maximum Load.

PubMed

Pestaña-Melero, Francisco Luis; Haff, G Gregory; Rojas, Francisco Javier; Pérez-Castilla, Alejandro; García-Ramos, Amador

2017-12-18

This study aimed to compare the between-session reliability of the load-velocity relationship between (1) linear vs. polynomial regression models, (2) concentric-only vs. eccentric-concentric bench press variants, as well as (3) the within-participants vs. the between-participants variability of the velocity attained at each percentage of the one-repetition maximum (%1RM). The load-velocity relationship of 30 men (age: 21.2±3.8 y; height: 1.78±0.07 m, body mass: 72.3±7.3 kg; bench press 1RM: 78.8±13.2 kg) were evaluated by means of linear and polynomial regression models in the concentric-only and eccentric-concentric bench press variants in a Smith Machine. Two sessions were performed with each bench press variant. The main findings were: (1) first-order-polynomials (CV: 4.39%-4.70%) provided the load-velocity relationship with higher reliability than second-order-polynomials (CV: 4.68%-5.04%); (2) the reliability of the load-velocity relationship did not differ between the concentric-only and eccentric-concentric bench press variants; (3) the within-participants variability of the velocity attained at each %1RM was markedly lower than the between-participants variability. Taken together, these results highlight that, regardless of the bench press variant considered, the individual determination of the load-velocity relationship by a linear regression model could be recommended to monitor and prescribe the relative load in the Smith machine bench press exercise.

A comparison of peak power in the shoulder press and shoulder throw.

PubMed

Dalziel, W M; Neal, R J; Watts, M C

2002-09-01

The ability to generate peak power is central for performance in many sports. Currently two distinct resistance training methods are used to develop peak power, the heavy weight/slow velocity and light weight/fast velocity regimes. When using the light weight/fast velocity power training method it was proposed that peak power would be greater in a shoulder throw exercise compared with a normal shoulder press. Nine males performed three lifts in the shoulder press and shoulder throw at 30% and 40% of their one repetition maximum (1RM). These lifts were performed identically, except for the release of the bar in the throw condition. A potentiometer attached to the bar measured displacement and duration of the lifts. The time of bar release in the shoulder throw was determined with a pressure switch. ANOVA was used to examine statistically significant differences where the level of acceptance was set at p < 0.05. Peak power was found to be significantly greater in the shoulder throw at 30% of 1 RM condition [F, (1, 23) = 2.325 p < 0.051 and at 40% of 1 RM [F, (1, 23) = 2.905 p < 0.05] compared to values recorded for the respective shoulder presses. Peak power was also greater in the 30% of 1 RM shoulder throw (510 +/- 103W) than in the 40% of 1 RM shoulder press (471 +/- 96W). Peak power was produced significantly later in the shoulder throw versus the shoulder press. This differing power reflected a greater bar velocity of the shoulder throw at both assigned weights compared with the shoulder press.

The effects of training volume and competition on the salivary cortisol concentrations of Olympic weightlifters.

PubMed

Crewther, Blair T; Heke, Taati; Keogh, Justin W L

2011-01-01

This study examined the effects of training volume and competition on the salivary cortisol (Sal-C) concentrations of Olympic weightlifters. Male (n = 5) and female (n = 4) Olympic weightlifters provided saliva samples across a 5-week experimental = period. The first aim was to assess the weekly effects of high (≥ 200 sets) and low (≤ 100 sets) training volume on Sal-C. The second aim was to compare Sal-C concentrations and 1 repetition maximum (1RM) performance during 2 simulated and 2 actual competitions. Performance was assessed using the snatch, clean and jerk, and the Olympic total lift. Data from each competition setting were pooled before analysis. There were no significant weekly changes in Sal-C levels (p > 0.05). The actual competitions produced higher (128-130%) Sal-C concentrations (p < 0.001) and superior 1RM lifts (1.9-2.6%) for the clean and jerk, and the Olympic total, than the simulated competitions (p < 0.05). Individual Sal-C concentrations before the simulated competitions were positively correlated to all of the 1RM lifts (r = 0.48-0.49, p < 0.05). In conclusion, actual competitions produced greater Sal-C responses than simulated competitions, and this appeared to benefit the 1RM performance of Olympic weightlifters. Individuals with higher Sal-C concentrations also tended to exhibit superior 1RM lifts during the simulated competitions. Given these findings, greater emphasis should be placed upon the monitoring of C to establish normative values, training standards and to assist with performance prediction.

Validity of the Myotest® in measuring force and power production in the squat and bench press.

PubMed

Comstock, Brett A; Solomon-Hill, Glenn; Flanagan, Shawn D; Earp, Jacob E; Luk, Hui-Ying; Dobbins, Kathryn A; Dunn-Lewis, Courtenay; Fragala, Maren S; Ho, Jen-Yu; Hatfield, Disa L; Vingren, Jakob L; Denegar, Craig R; Volek, Jeff S; Kupchak, Brian R; Maresh, Carl M; Kraemer, William J

2011-08-01

The purpose of this study was to verify the concurrent validity of a bar-mounted Myotest® instrument in measuring the force and power production in the squat and bench press exercises when compared to the gold standard of a computerized linear transducer and force platform system. Fifty-four men (bench press: 39-171 kg; squat: 75-221 kg) and 43 women (bench press: 18-80 kg; squat: 30-115 kg) (age range 18-30 years) performed a 1 repetition maximum (1RM) strength test in bench press and squat exercises. Power testing consisted of the jump squat and the bench throw at 30% of each subject's 1RM. During each measurement, both the Myotest® instrument and the Celesco linear transducer of the directly interfaced BMS system (Ballistic Measurement System [BMS] Innervations Inc, Fitness Technology force plate, Skye, South Australia, Australia) were mounted to the weight bar. A strong, positive correlation (r) between the Myotest and BMS systems and a high correlation of determination (R2) was demonstrated for bench throw force (r = 0.95, p < 0.05) (R2 = 0.92); bench throw power (r = 0.96, p < 0.05) (R2 = 0.93); squat jump force (r = 0.98, p < 0.05) (R2 = 0.97); and squat jump power (r = 0.91, p < 0.05) (R2 = 0.82). In conclusion, when fixed on the bar in the vertical axis, the Myotest is a valid field instrument for measuring force and power in commonly used exercise movements.

The biomechanical and perceptual influence of chain resistance on the performance of the olympic clean.

PubMed

Berning, Joseph M; Coker, Cheryl A; Briggs, Doug

2008-03-01

Proponents of chain training suggest that using chains hung from the ends of barbells rather than using conventional barbells alone enhances strength, power, and neuromuscular adaptations. The purpose of this study was to determine whether a conventional barbell with chains compared to a conventional barbell without chains would affect the performance of an Olympic Clean. The subjects were also asked regarding their perception of how chains affected their lifting. Four male and 3 female competitive weightlifters who used chains as part of their training participated in the study. The testing protocol compared the subjects' lifting 80% and 85% of their 1 repetition maximum (1RM) using conventional barbells and their lifting 80% and 85% of their 1RM using chains (75% conventional barbells + 5% chains and 80% conventional barbells + 5% chains, respectively). Video analysis evaluated the bar's vertical displacement and velocity and the rate of force production. Vertical ground reaction forces for the first-pull, unweighting, and second-pull phases of the lift were evaluated by using a force plate. After testing, the subjects completed a 2-item questionnaire asking individual perception of the effects of the chains. The results showed no significant difference for condition for any of the variables examined. In contrast, all subjects perceived that the chains required a greater effort. In conclusion, the results indicated that the addition of chains provided no greater value over lifting conventional barbells alone in the performance of the Olympic Clean, although the subjects perceived the chains to have a positive effect.

Predicting the Size of Sunspot Cycle 24 on the Basis of Single- and Bi-Variate Geomagnetic Precursor Methods

NASA Technical Reports Server (NTRS)

Wilson, Robert M.; Hathaway, David H.

2009-01-01

Examined are single- and bi-variate geomagnetic precursors for predicting the maximum amplitude (RM) of a sunspot cycle several years in advance. The best single-variate fit is one based on the average of the ap index 36 mo prior to cycle minimum occurrence (E(Rm)), having a coefficient of correlation (r) equal to 0.97 and a standard error of estimate (se) equal to 9.3. Presuming cycle 24 not to be a statistical outlier and its minimum in March 2008, the fit suggests cycle 24 s RM to be about 69 +/- 20 (the 90% prediction interval). The weighted mean prediction of 11 statistically important single-variate fits is 116 +/- 34. The best bi-variate fit is one based on the maximum and minimum values of the 12-mma of the ap index; i.e., APM# and APm*, where # means the value post-E(RM) for the preceding cycle and * means the value in the vicinity of cycle minimum, having r = 0.98 and se = 8.2. It predicts cycle 24 s RM to be about 92 +/- 27. The weighted mean prediction of 22 statistically important bi-variate fits is 112 32. Thus, cycle 24's RM is expected to lie somewhere within the range of about 82 to 144. Also examined are the late-cycle 23 behaviors of geomagnetic indices and solar wind velocity in comparison to the mean behaviors of cycles 2023 and the geomagnetic indices of cycle 14 (RM = 64.2), the weakest sunspot cycle of the modern era.

Effect of cluster set warm-up configurations on sprint performance in collegiate male soccer players.

PubMed

Nickerson, Brett S; Mangine, Gerald T; Williams, Tyler D; Martinez, Ismael A

2018-06-01

The purpose of this study was to determine if back squat cluster sets (CS) with varying inter-repetition rest periods would potentiate greater sprint performance compared with a traditional set parallel back squat in collegiate soccer players. Twelve collegiate male soccer players (age, 21.0 ± 2.0 years; height, 180.0 ± 9.0 cm; body mass, 79.0 ± 9.5 kg) performed a 20-m sprint prior to a potentiation complex and at 1, 4, 7, and 10 min postexercise on 3 separate, randomized occasions. On each occasion, the potentiation complex consisted of 1 set of 3 repetitions at 85% 1-repetition maximum (1RM) for the traditional parallel back squat. However, on 1 occasion the 3-repetition set was performed in a traditional manner (i.e., continuously), whereas on the other 2 occasions, 30s (CS 30 ) and 60 s (CS 60 ) of rest were allotted between each repetition. Repeated-measures ANOVA revealed greater (p = 0.022) mean barbell velocity on CS 60 compared with the traditional set. However, faster (p < 0.040) 20-m sprint times were observed for CS 30 (3.15 ± 0.16 s) compared with traditional (3.20 ± 0.17 s) only at 10 min postexercise. No other differences were observed. These data suggest that a single cluster set of 3 repetitions with 30-s inter-repetition rest periods at 85% 1RM acutely improves 20-m sprinting performance. Strength and conditioning professionals and their athletes might consider its inclusion during the specific warm-up to acutely improve athletic performance during the onset (≤10 min) of training or competition.

Acute Effects of Elastic Bands on Kinetic Characteristics During the Deadlift at Moderate and Heavy Loads.

PubMed

Galpin, Andrew J; Malyszek, Kylie K; Davis, Kyle A; Record, Shaina M; Brown, Lee E; Coburn, Jared W; Harmon, RoQue A; Steele, Jeff M; Manolovitz, Adam D

2015-12-01

Loading a barbell with variable resistance positively alters kinetic characteristics during the back squat and bench press but has never been studied during the deadlift. The purpose of this project was to examine the acute effects of combining elastic bands and free weights during the deadlift at moderate and heavy loads. Twelve trained men (age: 24.08 ± 2.35 years, height: 175.94 ± 5.38 cm, mass: 85.58 ± 12.49 kg, deadlift 1 repetition maximum (RM): 188.64 ± 16.13 kg) completed 2 variable resistance (B1 and B2) and 1 traditional free-weight (NB) condition at both 60 and 85% 1RM on a force plate. B1 had 15% resistance from bands, with the remaining 85% from free weights. B2 had 35% bands and 65% free weights. NB used free weights only. Average resistance was equated for all conditions. Power and velocity generally increased, whereas force decreased with the addition of bands. The amount of band tension (B1 or B2) had little impact on power when lifting at 60% 1RM. However, greater resistance from bands resulted in greater peak and relative power when lifting at 85% 1RM. Adding elastic bands decreased time to peak force (PF), time between PF and peak power (PP), and time between PF and peak velocity (PV) when compared with NB at 60% 1RM (NB > B1 > B2). These differences only reached significance for NB > B2 when lifting at 85% 1RM. These same differences existed for time between PP and PV. Thus, the amount of tension from bands has less impact on interpeak variables at heavier absolute loads. Practitioners should consider using heavy bands when prescribing the deadlift for speed or power, but not maximal force.

Validity and Reliability of the PUSH Wearable Device to Measure Movement Velocity During the Back Squat Exercise.

PubMed

Balsalobre-Fernández, Carlos; Kuzdub, Matt; Poveda-Ortiz, Pedro; Campo-Vecino, Juan Del

2016-07-01

Balsalobre-Fernández, C, Kuzdub, M, Poveda-Ortiz, P, and Campo-Vecino, Jd. Validity and reliability of the PUSH wearable device to measure movement velocity during the back squat exercise. J Strength Cond Res 30(7): 1968-1974, 2016-The purpose of this study was to analyze the validity and reliability of a wearable device to measure movement velocity during the back squat exercise. To do this, 10 recreationally active healthy men (age = 23.4 ± 5.2 years; back squat 1 repetition maximum [1RM] = 83 ± 8.2 kg) performed 3 repetitions of the back squat exercise with 5 different loads ranging from 25 to 85% 1RM on a Smith Machine. Movement velocity for each of the total 150 repetitions was simultaneously recorded using the T-Force linear transducer (LT) and the PUSH wearable band. Results showed a high correlation between the LT and the wearable device mean (r = 0.85; standard error of estimate [SEE] = 0.08 m·s) and peak velocity (r = 0.91, SEE = 0.1 m·s). Moreover, there was a very high agreement between these 2 devices for the measurement of mean (intraclass correlation coefficient [ICC] = 0.907) and peak velocity (ICC = 0.944), although a systematic bias between devices was observed (PUSH peak velocity being -0.07 ± 0.1 m·s lower, p ≤ 0.05). When measuring the 3 repetitions with each load, both devices displayed almost equal reliability (Test-retest reliability: LT [r = 0.98], PUSH [r = 0.956]; ICC: LT [ICC = 0.989], PUSH [ICC = 0.981]; coefficient of variation [CV]: LT [CV = 4.2%], PUSH [CV = 5.0%]). Finally, individual load-velocity relationships measured with both the LT (R = 0.96) and the PUSH wearable device (R = 0.94) showed similar, very high coefficients of determination. In conclusion, these results support the use of an affordable wearable device to track velocity during back squat training. Wearable devices, such as the one in this study, could have valuable practical applications for strength and conditioning coaches.

Plasma hormones, muscle mass and strength in resistance-trained postmenopausal women.

PubMed

Orsatti, Fabio L; Nahas, Eliana A P; Maesta, Nailza; Nahas-Neto, Jorge; Burini, Roberto C

2008-04-20

To associate changes of body composition, muscle strength (MS) and plasma hormones (PH) in resistance-training protocol in sedentary postmenopausal women (PMW). This randomized controlled trial, Brazilian 43 PMW (45-70-year-old) able for physical exercises were selected after they have accomplished medical and ethical criteria. They were assigned in two groups: RT, resistance training (n=22); and CT, not trained control (n=21); with supervision sessions of two to three exercise for large and one exercise for smaller groups in three series of 8-12 rep. (60-80%1RM) for each exercise. The training period lasted 16 weeks and was preceded by low-load exercise (40-50%1RM) adaptation period of 4 weeks (3/(times week)). Body weight, height, body mass index (BMI), and composition (BIA) along with fast-PH (FSH, LH, estradiol, cortisol, IGF-1 and testosterone) were assessed before (M0) and after (M16) the 4 weeks period with the MS (1RM) determined also at 8 weeks (M8). The values were correlated by Person's test and the means compared by Student's t-test and ANOVA. At baseline both groups were similar in age, time of PMW, body composition, MS and fast-PH. However after 16 weeks, RT presented higher BMI (2.1%), IGF-1 (37.8%) and MM gain (1.8+/-0.8 kg) than CT. MM correlated positively with IGF-1 (r=0.45, p<0.05) and MS progressively increased in all exercise greater in pectoral than legs and upper arms. Former sedentary postmenopausal women submitted to resistance training gained MM and MS irrespectively of fat mass changes but significantly associated with IGF-1 increase.

Effects of Strength vs. Ballistic-Power Training on Throwing Performance

PubMed Central

Zaras, Nikolaos; Spengos, Konstantinos; Methenitis, Spyridon; Papadopoulos, Constantinos; Karampatsos, Giorgos; Georgiadis, Giorgos; Stasinaki, Aggeliki; Manta, Panagiota; Terzis, Gerasimos

2013-01-01

The purpose of the present study was to investigate the effects of 6 weeks strength vs. ballistic-power (Power) training on shot put throwing performance in novice throwers. Seventeen novice male shot-put throwers were divided into Strength (N = 9) and Power (n = 8) groups. The following measurements were performed before and after the training period: shot put throws, jumping performance (CMJ), Wingate anaerobic performance, 1RM strength, ballistic throws and evaluation of architectural and morphological characteristics of vastus lateralis. Throwing performance increased significantly but similarly after Strength and Power training (7.0-13.5% vs. 6.0-11.5%, respectively). Muscular strength in leg press increased more after Strength than after Power training (43% vs. 21%, respectively), while Power training induced an 8.5% increase in CMJ performance and 9.0 - 25.8% in ballistic throws. Peak power during the Wingate test increased similarly after Strength and Power training. Muscle thickness increased only after Strength training (10%, p < 0.05). Muscle fibre Cross Sectional Area (fCSA) increased in all fibre types after Strength training by 19-26% (p < 0.05), while only type IIx fibres hypertrophied significantly after Power training. Type IIx fibres (%) decreased after Strength but not after Power training. These results suggest that shot put throwing performance can be increased similarly after six weeks of either strength or ballistic power training in novice throwers, but with dissimilar muscular adaptations. Key points Ballistic-power training with 30% of 1RM is equally effective in increasing shot put performance as strength training, in novice throwers, during a short training cycle of six weeks. In novice shot putters with relatively low initial muscle strength/mass, short-term strength training might be more important since it can increase both muscle strength and shot put performance. The ballistic type of power training resulted in a significant increase of the mass of type IIx muscle fibres and no change in their proportion. Thus, this type of training might be used effectively during the last weeks before competition, when the strength training load is usually reduced, in order to increase muscle power and shot put performance in novice shot putters. PMID:24149736

Effects of Strength vs. Ballistic-Power Training on Throwing Performance.

PubMed

Zaras, Nikolaos; Spengos, Konstantinos; Methenitis, Spyridon; Papadopoulos, Constantinos; Karampatsos, Giorgos; Georgiadis, Giorgos; Stasinaki, Aggeliki; Manta, Panagiota; Terzis, Gerasimos

2013-01-01

The purpose of the present study was to investigate the effects of 6 weeks strength vs. ballistic-power (Power) training on shot put throwing performance in novice throwers. Seventeen novice male shot-put throwers were divided into Strength (N = 9) and Power (n = 8) groups. The following measurements were performed before and after the training period: shot put throws, jumping performance (CMJ), Wingate anaerobic performance, 1RM strength, ballistic throws and evaluation of architectural and morphological characteristics of vastus lateralis. Throwing performance increased significantly but similarly after Strength and Power training (7.0-13.5% vs. 6.0-11.5%, respectively). Muscular strength in leg press increased more after Strength than after Power training (43% vs. 21%, respectively), while Power training induced an 8.5% increase in CMJ performance and 9.0 - 25.8% in ballistic throws. Peak power during the Wingate test increased similarly after Strength and Power training. Muscle thickness increased only after Strength training (10%, p < 0.05). Muscle fibre Cross Sectional Area (fCSA) increased in all fibre types after Strength training by 19-26% (p < 0.05), while only type IIx fibres hypertrophied significantly after Power training. Type IIx fibres (%) decreased after Strength but not after Power training. These results suggest that shot put throwing performance can be increased similarly after six weeks of either strength or ballistic power training in novice throwers, but with dissimilar muscular adaptations. Key pointsBallistic-power training with 30% of 1RM is equally effective in increasing shot put performance as strength training, in novice throwers, during a short training cycle of six weeks.In novice shot putters with relatively low initial muscle strength/mass, short-term strength training might be more important since it can increase both muscle strength and shot put performance.The ballistic type of power training resulted in a significant increase of the mass of type IIx muscle fibres and no change in their proportion. Thus, this type of training might be used effectively during the last weeks before competition, when the strength training load is usually reduced, in order to increase muscle power and shot put performance in novice shot putters.

The effects of pre versus post workout supplementation of creatine monohydrate on body composition and strength

PubMed Central

2013-01-01

Background Chronic supplementation with creatine monohydrate has been shown to promote increases in total intramuscular creatine, phosphocreatine, skeletal muscle mass, lean body mass and muscle fiber size. Furthermore, there is robust evidence that muscular strength and power will also increase after supplementing with creatine. However, it is not known if the timing of creatine supplementation will affect the adaptive response to exercise. Thus, the purpose of this investigation was to determine the difference between pre versus post exercise supplementation of creatine on measures of body composition and strength. Methods Nineteen healthy recreational male bodybuilders (mean ± SD; age: 23.1 ± 2.9; height: 166.0 ± 23.2 cm; weight: 80.18 ± 10.43 kg) participated in this study. Subjects were randomly assigned to one of the following groups: PRE-SUPP or POST-SUPP workout supplementation of creatine (5 grams). The PRE-SUPP group consumed 5 grams of creatine immediately before exercise. On the other hand, the POST-SUPP group consumed 5 grams immediately after exercise. Subjects trained on average five days per week for four weeks. Subjects consumed the supplement on the two non-training days at their convenience. Subjects performed a periodized, split-routine, bodybuilding workout five days per week (Chest-shoulders-triceps; Back-biceps, Legs, etc.). Body composition (Bod Pod®) and 1-RM bench press (BP) were determined. Diet logs were collected and analyzed (one random day per week; four total days analyzed). Results 2x2 ANOVA results - There was a significant time effect for fat-free mass (FFM) (F = 19.9; p = 0.001) and BP (F = 18.9; p < 0.001), however, fat mass (FM) and body weight did not reach significance. While there were trends, no significant interactions were found. However, using magnitude-based inference, supplementation with creatine post workout is possibly more beneficial in comparison to pre workout supplementation with regards to FFM, FM and 1-RM BP. The mean change in the PRE-SUPP and POST-SUPP groups for body weight (BW kg), FFM (kg), FM (kg) and 1-RM bench press (kg) were as follows, respectively: Mean ± SD; BW: 0.4 ± 2.2 vs. 0.8 ± 0.9; FFM: 0.9 ± 1.8 vs. 2.0 ± 1.2; FM: -0.1 ± 2.0 vs. −1.2 ± 1.6; Bench Press 1-RM: 6.6 ± 8.2 vs. 7.6 ± 6.1. Qualitative inference represents the likelihood that the true value will have the observed magnitude. Furthermore, there were no differences in caloric or macronutrient intake between the groups. Conclusions Creatine supplementation plus resistance exercise increases fat-free mass and strength. Based on the magnitude inferences it appears that consuming creatine immediately post-workout is superior to pre-workout vis a vis body composition and strength. PMID:23919405

The effects of pre versus post workout supplementation of creatine monohydrate on body composition and strength.

PubMed

Antonio, Jose; Ciccone, Victoria

2013-01-01

Chronic supplementation with creatine monohydrate has been shown to promote increases in total intramuscular creatine, phosphocreatine, skeletal muscle mass, lean body mass and muscle fiber size. Furthermore, there is robust evidence that muscular strength and power will also increase after supplementing with creatine. However, it is not known if the timing of creatine supplementation will affect the adaptive response to exercise. Thus, the purpose of this investigation was to determine the difference between pre versus post exercise supplementation of creatine on measures of body composition and strength. Nineteen healthy recreational male bodybuilders (mean ± SD; age: 23.1 ± 2.9; height: 166.0 ± 23.2 cm; weight: 80.18 ± 10.43 kg) participated in this study. Subjects were randomly assigned to one of the following groups: PRE-SUPP or POST-SUPP workout supplementation of creatine (5 grams). The PRE-SUPP group consumed 5 grams of creatine immediately before exercise. On the other hand, the POST-SUPP group consumed 5 grams immediately after exercise. Subjects trained on average five days per week for four weeks. Subjects consumed the supplement on the two non-training days at their convenience. Subjects performed a periodized, split-routine, bodybuilding workout five days per week (Chest-shoulders-triceps; Back-biceps, Legs, etc.). Body composition (Bod Pod®) and 1-RM bench press (BP) were determined. Diet logs were collected and analyzed (one random day per week; four total days analyzed). 2x2 ANOVA results - There was a significant time effect for fat-free mass (FFM) (F = 19.9; p = 0.001) and BP (F = 18.9; p < 0.001), however, fat mass (FM) and body weight did not reach significance. While there were trends, no significant interactions were found. However, using magnitude-based inference, supplementation with creatine post workout is possibly more beneficial in comparison to pre workout supplementation with regards to FFM, FM and 1-RM BP. The mean change in the PRE-SUPP and POST-SUPP groups for body weight (BW kg), FFM (kg), FM (kg) and 1-RM bench press (kg) were as follows, respectively: Mean ± SD; BW: 0.4 ± 2.2 vs. 0.8 ± 0.9; FFM: 0.9 ± 1.8 vs. 2.0 ± 1.2; FM: -0.1 ± 2.0 vs. -1.2 ± 1.6; Bench Press 1-RM: 6.6 ± 8.2 vs. 7.6 ± 6.1. Qualitative inference represents the likelihood that the true value will have the observed magnitude. Furthermore, there were no differences in caloric or macronutrient intake between the groups. Creatine supplementation plus resistance exercise increases fat-free mass and strength. Based on the magnitude inferences it appears that consuming creatine immediately post-workout is superior to pre-workout vis a vis body composition and strength.

Does extensive on-water rowing increase muscular strength and endurance?

PubMed

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

2012-01-01

The purpose of this study was to compare changes in aerobic condition, strength, and muscular endurance following 8 weeks of endurance rowing alone or in combination with weight-training. Twenty-two elite rowers were assigned to (1) rowing (n = 10, 250-270 km · week⁻¹) or (2) rowing (n = 12, 190-210 km · week⁻¹) plus four weight-training sessions each week. Pre and post mean and standardized effect-size (ES) differences in aerobic condition (watts at 4 mmol · L⁻¹) and strength (isometric pull, N), prone bench-pull (6-repetition maximum, 6-RM), 5- and 30-repetition leg-press and 60-repetition seated-arm-pull (J, performed on a dynamometer) normalized by body mass and log-transformed were analysed, after adjusting for gender. The standardized differences between groups were trivial for aerobic condition (ES [±90% CI] = 0.15; ±0.28, P = 0.37) and prone bench-pull (ES = 0.27; ±0.33, P = 0.18), although a moderate positive benefit in favour of rowing only was observed for the seated-arm-pull (ES = 0.42; ±0.4, P = 0.08). Only the weight-training group improved isometric pull (12.4 ± 8.9%, P < 0.01), 5-repetition (4.0 ± 5.7%, P < 0.01) and 30-repetition (2.4 ± 5.4%, P < 0.01) leg-press. In conclusion, while gains in aerobic condition and upper-body strength were comparable to extensive endurance rowing, weight-training led to moderately greater lower-body muscular-endurance and strength gains.

Comparison of hydrodynamic simulations with two-shockwave drive target experiments

NASA Astrophysics Data System (ADS)

Karkhanis, Varad; Ramaprabhu, Praveen; Buttler, William

2015-11-01

We consider hydrodynamic continuum simulations to mimic ejecta generation in two-shockwave target experiments, where metallic surface is loaded by two successive shock waves. Time of second shock in simulations is determined to match experimental amplitudes at the arrival of the second shock. The negative Atwood number A --> - 1 of ejecta simulations leads to two successive phase inversions of the interface corresponding to the passage of the shocks from heavy to light media in each instance. Metallic phase of ejecta (solid/liquid) depends on shock loading pressure in the experiment, and we find that hydrodynamic simulations quantify the liquid phase ejecta physics with a fair degree of accuracy, where RM instability is not suppressed by the strength effect. In particular, we find that our results of free surface velocity, maximum ejecta velocity, and maximum ejecta areal density are in excellent agreement with their experimental counterparts, as well as ejecta models. We also comment on the parametric space for hydrodynamic simulations in which they can be used to compare with the target experiments. This work was supported in part by the (U.S.) Department of Energy (DOE) under Contract No. DE-AC52-06NA2-5396.

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.

Does insulin-like growth factor 1 genotype influence muscle power response to strength training in older men and women?

PubMed

Sood, Suchi; Hanson, Erik D; Delmonico, Matthew J; Kostek, Matthew C; Hand, Brian D; Roth, Stephen M; Hurley, Ben F

2012-02-01

The CA-repeat polymorphism in the insulin-like growth factor 1 (IGF1) gene promoter region has been associated with strength and circulating IGF-I protein levels. The purpose of the study was to determine if the IGF1 CA-repeat polymorphism influences muscle power at baseline and in response to ST in older adults. Knee extensor peak power (PP) was measured at 50, 60, and 70% of 1-RM strength before and after 10 weeks of unilateral knee extensor ST in older adults, aged 50-85 years, to determine the changes in absolute and relative PP with ST. Subjects (N = 114) were genotyped for the IGF1 CA-repeat polymorphism and grouped as homozygous for the 192 allele, heterozygous, or non-carriers of the 192 allele. The 192 homozygotes had significantly lower baseline PP at 50, 60, and 70% of 1-RM strength than the non-carriers when age, sex, and baseline fat-free mass were covaried (all P < 0.05). This same relationship was observed when the highest PP within these ranges was compared (e.g., 317.6 ± 13.5 for 192 homozygotes and 380.2 ± 16.3 for non-carriers of the 192 allele, P < 0.05). Both absolute and relative PP increased significantly with ST in all genotype groups as expected, but there were no significant relationships among IGF1 genotypes and any of the PP changes. Despite a significant relationship between IGF1 genotype and knee extensor peak power at baseline, IGF1 genotype does not appear to influence changes in knee extensor peak power with ST.

The effects of a 6-month resistance training and dried plum consumption intervention on strength, body composition, blood markers of bone turnover, and inflammation in breast cancer survivors.

PubMed

Simonavice, Emily; Liu, Pei-Yang; Ilich, Jasminka Z; Kim, Jeong-Su; Arjmandi, Bahram; Panton, Lynn B

2014-06-01

The purpose of this study was to examine the effects of resistance training (RT) and dried plum (DP) consumption on strength, body composition, blood markers of bone, and inflammation in breast cancer survivors (BCS). Twenty-three BCS (RT, n = 12; RT+DP, n = 11), aged 64 ± 7 years, were evaluated at baseline and after 6 months of intervention on the following: muscular strength (chest press and leg extension) via 1-repetition maximums (1RMs); body composition, specifically bone mineral density (BMD) by dual energy X-ray absorptiometry; biochemical markers of bone turnover (bone-specific alkaline phosphatase (BAP), tartrate resistant acid phosphatase (TRAP-5b)); and inflammation (C-reactive protein (CRP)). Target RT prescription was 2 days/week of 10 exercises, including 2 sets of 8-12 repetitions at ∼60%-80% of 1RM. RT+DP also consumed 90 g of DP daily. There were no baseline differences between groups or any group-by-time interactions for any of the variables. BCS increased upper (p < 0.05) (RT: 64 ± 14 to 80 ± 17 kg; RT+DP: 72 ± 23 to 91 ± 20 kg) and lower (p < 0.05) (RT: 69 ± 20 to 87 ± 28 kg; RT+DP: 78 ± 19 to 100 ± 21 kg) body strength. Body composition and BMD improvements were not observed. TRAP-5b decreased in the RT group (p < 0.05) (4.55 ± 1.57 to 4.04 ± 1.63 U/L) and the RT+DP group (p = 0.07) (5.10 ± 2.75 to 4.27 ± 2.03 U/L). Changes in BAP and CRP were not observed. RT was effective for improving biochemical markers of bone turnover and muscular strength in BCS. A longer and higher intensity intervention may be needed to reveal the true effects of RT and DP on body composition and biochemical markers of inflammation.

Effect of acute exposure to moderate altitude on muscle power: hypobaric hypoxia vs. normobaric hypoxia.

PubMed

Feriche, Belén; García-Ramos, Amador; Calderón-Soto, Carmen; Drobnic, Franchek; Bonitch-Góngora, Juan G; Galilea, Pedro A; Riera, Joan; Padial, Paulino

2014-01-01

When ascending to a higher altitude, changes in air density and oxygen levels affect the way in which explosive actions are executed. This study was designed to compare the effects of acute exposure to real or simulated moderate hypoxia on the dynamics of the force-velocity relationship observed in bench press exercise. Twenty-eight combat sports athletes were assigned to two groups and assessed on two separate occasions: G1 (n = 17) in conditions of normoxia (N1) and hypobaric hypoxia (HH) and G2 (n = 11) in conditions of normoxia (N2) and normobaric hypoxia (NH). Individual and complete force-velocity relationships in bench press were determined on each assessment day. For each exercise repetition, we obtained the mean and peak velocity and power shown by the athletes. Maximum power (Pmax) was recorded as the highest P(mean) obtained across the complete force-velocity curve. Our findings indicate a significantly higher absolute load linked to P(max) (∼ 3%) and maximal strength (1 RM) (∼ 6%) in G1 attributable to the climb to altitude (P<0.05). We also observed a stimulating effect of natural hypoxia on P(mean) and P(peak) in the middle-high part of the curve (≥ 60 kg; P<0.01) and a 7.8% mean increase in barbell displacement velocity (P<0.001). No changes in any of the variables examined were observed in G2. According to these data, we can state that acute exposure to natural moderate altitude as opposed to simulated normobaric hypoxia leads to gains in 1 RM, movement velocity and power during the execution of a force-velocity curve in bench press.

Effect of Acute Exposure to Moderate Altitude on Muscle Power: Hypobaric Hypoxia vs. Normobaric Hypoxia

PubMed Central

Feriche, Belén; García-Ramos, Amador; Calderón-Soto, Carmen; Drobnic, Franchek; Bonitch- Góngora, Juan G.; Galilea, Pedro A.; Riera, Joan; Padial, Paulino

2014-01-01

When ascending to a higher altitude, changes in air density and oxygen levels affect the way in which explosive actions are executed. This study was designed to compare the effects of acute exposure to real or simulated moderate hypoxia on the dynamics of the force-velocity relationship observed in bench press exercise. Twenty-eight combat sports athletes were assigned to two groups and assessed on two separate occasions: G1 (n = 17) in conditions of normoxia (N1) and hypobaric hypoxia (HH) and G2 (n = 11) in conditions of normoxia (N2) and normobaric hypoxia (NH). Individual and complete force-velocity relationships in bench press were determined on each assessment day. For each exercise repetition, we obtained the mean and peak velocity and power shown by the athletes. Maximum power (Pmax) was recorded as the highest Pmean obtained across the complete force-velocity curve. Our findings indicate a significantly higher absolute load linked to Pmax (∼3%) and maximal strength (1RM) (∼6%) in G1 attributable to the climb to altitude (P<0.05). We also observed a stimulating effect of natural hypoxia on Pmean and Ppeak in the middle-high part of the curve (≥60 kg; P<0.01) and a 7.8% mean increase in barbell displacement velocity (P<0.001). No changes in any of the variables examined were observed in G2. According to these data, we can state that acute exposure to natural moderate altitude as opposed to simulated normobaric hypoxia leads to gains in 1RM, movement velocity and power during the execution of a force-velocity curve in bench press. PMID:25474104

Fatigue effects upon sticking region and electromyography in a six-repetition maximum bench press.

PubMed

van den Tillaar, Roland; Saeterbakken, Atle Hole

2013-01-01

The aim of the study was to examine the sticking region and concomitant neuromuscular activation of the prime movers during six-repetition maximum (RM) bench pressing. We hypothesised that both peak velocities would decrease and that the electromyography (EMG) of the prime movers (deltoid, major pectoralis and triceps) would increase during the pre-sticking and sticking region during the six repetitions due to fatigue. Thirteen resistance-trained males (age 22.8 ± 2.2 years, stature 1.82 ± 0.06 m, body mass 83.4 ± 7.6 kg) performed 6-RM bench presses. Barbell kinematics and EMG activity of pectoralis major, deltoid anterior, and triceps brachii during the pre-, sticking and post-sticking region of each repetition in a 6-RM bench press were analysed. For both the sticking as the post-sticking region, the time increased significantly from the first to the sixth repetition. Vertical barbell height at the start of sticking region was lower, while the height at the end of the sticking region and post-sticking region did not change during the six repetitions. It was concluded that in 6-RM bench pressing performance, the sticking region is a poor mechanical force region due to the unchanged barbell height at the end of the sticking region. Furthermore, when fatigue occurs, the pectoralis and the deltoid muscles are responsible for surpassing the sticking region as indicated by their increased activity during the pre- and sticking region during the six-repetitions bench press.

Thermo-Acidic Pretreatment of Beach Macroalgae from Rügen to Optimize Biomethane Production—Double Benefit with Simultaneous Bioenergy Production and Improvement of Local Beach and Waste Management

PubMed Central

Barbot, Yann Nicolas; Thomsen, Laurenz; Benz, Roland

2015-01-01

Eutrophication is a phenomenon which can rapidly generate masses of marine macroalgae, particularly in areas with high nutrient pollution. Washed ashore, this biomass impairs coastal tourism and negatively affects the coastal ecosystem. The present study evaluates the biochemical methane potential (BMP) of a macroalgae mix (Rügen-Mix, RM (RM = Rügen-Mix)) originating from Rügen, Germany. To improve biomethane recovery, thermo-acidic pretreatment was applied to the biomass prior to biomethanation to disintegrate the biomass macrostructure. Acid hydrolysis was successfully triggered with 0.2 M industry-grade HCl at 80 °C for a 2 h period, increasing biomethane recovery by +39%, with a maximum BMP of 121 mL·g−1 volatile solids (VS). To reduce the necessity for input material, HCl was replaced by the acidic waste product flue gas condensate (FGC). Improved performance was achieved by showing an increase in biomethane recovery of +24% and a maximum BMP of 108 mL·g−1 VS. Continuous anaerobic digestion trials of RM were conducted for three hydraulic retention times, showing the feasibility of monodigestion. The biomethane recovery was 60 mL and 65 mL·g−1 VS·d−1 for thermophilic and mesophilic operation, respectively. The quality of biomethanation performance aligned to the composition of the source material which exhibited a low carbon/nitrogen ratio and an increased concentration of sulfur compounds. PMID:26404327

Thermo-Acidic Pretreatment of Beach Macroalgae from Rügen to Optimize Biomethane Production--Double Benefit with Simultaneous Bioenergy Production and Improvement of Local Beach and Waste Management.

PubMed

Barbot, Yann Nicolas; Thomsen, Laurenz; Benz, Roland

2015-09-03

Eutrophication is a phenomenon which can rapidly generate masses of marine macroalgae, particularly in areas with high nutrient pollution. Washed ashore, this biomass impairs coastal tourism and negatively affects the coastal ecosystem. The present study evaluates the biochemical methane potential (BMP) of a macroalgae mix (Rügen-Mix, RM (RM = Rügen-Mix)) originating from Rügen, Germany. To improve biomethane recovery, thermo-acidic pretreatment was applied to the biomass prior to biomethanation to disintegrate the biomass macrostructure. Acid hydrolysis was successfully triggered with 0.2 M industry-grade HCl at 80 °C for a 2 h period, increasing biomethane recovery by +39%, with a maximum BMP of 121 mL·g(-1) volatile solids (VS). To reduce the necessity for input material, HCl was replaced by the acidic waste product flue gas condensate (FGC). Improved performance was achieved by showing an increase in biomethane recovery of +24% and a maximum BMP of 108 mL·g(-1) VS. Continuous anaerobic digestion trials of RM were conducted for three hydraulic retention times, showing the feasibility of monodigestion. The biomethane recovery was 60 mL and 65 mL·g(-1) VS·d(-1) for thermophilic and mesophilic operation, respectively. The quality of biomethanation performance aligned to the composition of the source material which exhibited a low carbon/nitrogen ratio and an increased concentration of sulfur compounds.

The Acute Effects of Back Squats on Vertical Jump Performance in Men and Women

PubMed Central

Witmer, Chad A.; Davis, Shala E.; Moir, Gavin L.

2010-01-01

The aim of the present study was to investigate the acute effects of performing back squats on subsequent performance during a series of vertical jumps in men and women. Twelve men and 12 women were tested on three separate occasions, the first of which was used to determine their 1-repetition maximum (1-RM) parallel back squat. Following this, subjects performed a potentiation and a control treatment in a counterbalanced order. The potentiation treatment culminated with subjects performing parallel back squats with a load equivalent to 70% 1- RM for three repetitions, following which they performed one countermovement vertical jump (CMJ) for maximal height every three minutes for a total of 10 jumps. During the control treatment, subjects performed only the CMJs. Jump height (JH) and vertical stiffness (VStiff) were calculated for each jump from the vertical force signal recorded from a force platform. There were no significant changes in JH or VStiff following the treatments and no significant differences in the responses between men and women (p > 0.05). Correlations between normalized 1-RM back squat load and the absolute change in JH and VStiff were small to moderate for both men and women, with most correlations being negative. Large variations in response to the back squats were noted in both men and women. The use of resistance exercises performed prior to a series of vertical jumps can result in improvements in performance in certain individuals, although the gains tend to be small and dependent upon the mechanical variable measured. There does not seem to be any differences between men and women in the response to dynamic potentiation protocols. Key points Substantial individual responses were noted in both men and women in response to the PAP protocol used in the present study. The choice of dependent variable influences the ef-ficacy of the PAP protocol, with JH and VStiff demonstrating disparate responses in individual sub-jects.Such individual responses may render such PAP protocols impractical for strength and conditioning practitioners as the protocols are likely to require in-dividualizing to each athlete. PMID:24149687

The acute effects of back squats on vertical jump performance in men and women.

PubMed

Witmer, Chad A; Davis, Shala E; Moir, Gavin L

2010-01-01

The aim of the present study was to investigate the acute effects of performing back squats on subsequent performance during a series of vertical jumps in men and women. Twelve men and 12 women were tested on three separate occasions, the first of which was used to determine their 1-repetition maximum (1-RM) parallel back squat. Following this, subjects performed a potentiation and a control treatment in a counterbalanced order. The potentiation treatment culminated with subjects performing parallel back squats with a load equivalent to 70% 1- RM for three repetitions, following which they performed one countermovement vertical jump (CMJ) for maximal height every three minutes for a total of 10 jumps. During the control treatment, subjects performed only the CMJs. Jump height (JH) and vertical stiffness (VStiff) were calculated for each jump from the vertical force signal recorded from a force platform. There were no significant changes in JH or VStiff following the treatments and no significant differences in the responses between men and women (p > 0.05). Correlations between normalized 1-RM back squat load and the absolute change in JH and VStiff were small to moderate for both men and women, with most correlations being negative. Large variations in response to the back squats were noted in both men and women. The use of resistance exercises performed prior to a series of vertical jumps can result in improvements in performance in certain individuals, although the gains tend to be small and dependent upon the mechanical variable measured. There does not seem to be any differences between men and women in the response to dynamic potentiation protocols. Key pointsSubstantial individual responses were noted in both men and women in response to the PAP protocol used in the present study.The choice of dependent variable influences the ef-ficacy of the PAP protocol, with JH and VStiff demonstrating disparate responses in individual sub-jects.Such individual responses may render such PAP protocols impractical for strength and conditioning practitioners as the protocols are likely to require in-dividualizing to each athlete.

Efficacy Of The Repetitions In Reserve-Based Rating Of Perceived Exertion For The Bench Press In Experienced And Novice Benchers.

PubMed

Ormsbee, Michael J; Carzoli, Joseph P; Klemp, Alex; Allman, Brittany R; Zourdos, Michael C; Kim, Jeong-Su; Panton, Lynn B

2017-03-13

Autoregulation (AR) is the practice of adjusting training variables in response to athlete feedback. One component of AR postulated to enhance resistance training adaptations involves implementing a resistance training-specific rating of perceived exertion (RPE) scale measuring repetitions in reserve (RIR). The purpose of this study was to examine the efficacy of this method using the bench press exercise. Twenty-seven college-aged men were assigned to one of two groups based upon training age: experience benchers (EB) (n=14, training age: 4.7±2.0 yrs) and novice benchers (NB) (n=13, training age: 1.1±0.6 yrs). Subjects performed one-repetition maximum (1RM) followed by single-repetition sets with loads corresponding to 60, 75, and 90% of 1RM and an 8-repetition set at 70% 1RM. Subjects reported a corresponding RPE, based on RIR, for every set. Average velocity was recorded for each single-repetition set along with the first and last repetitions of the 8-repetition set at 70% 1RM. Average velocity at 100% of 1RM in EB was slower (0.14±0.04 m[BULLET OPERATOR]s) compared to NB (0.20±0.05 m[BULLET OPERATOR]s) (p<0.001). EB recorded greater RPE than NB at 1RM (EB: 9.86±0.14 vs. NB: 9.35±0.36) (p=0.011). No between-group differences existed for average velocity or RPE at any other intensity. Both EB (r=0.85, p<0.001) and NB (r=0.85, p<0.001) had strong inverse significant correlations between average velocity and RPE at all intensities. Our findings suggest that the RIR-based RPE scale may be an efficacious approach for AR of bench press training load and volume in college-aged men.

Effect of a self-adhesive coating on the load-bearing capacity of tooth-coloured restorative materials.

PubMed

Bagheri, R; Palamara, Jea; Mese, A; Manton, D J

2017-03-01

The aim of this study was to compare the flexural strength and Vickers hardness of tooth-coloured restorative materials with and without applying a self-adhesive coating for up to 6 months. Specimens were prepared from three resin composites (RC), two resin-modified glass-ionomer cements (RM-GIC) and two conventional glass-ionomer cements (CGIC). All materials were tested both with and without applying G-Coat Plus (GCP). Specimens were conditioned in 37 °C distilled deionized water for 24 h, and 1, 3 and 6 months. The specimens were strength tested using a four-point bend test jig in a universal testing machine. The broken specimen's halves were used for Vickers hardness testing. Representative specimens were examined under an environmental scanning electron microscope. Data analysis showed that regardless of time and materials, generally the surface coating was associated with a significant increase in the flexural strength of the materials. Applying the GCP decreased the hardness of almost all materials significantly (P < 0.05) and effect of time intervals on hardness was material dependent. The load-bearing capacity of the restorative materials was affected by applying self-adhesive coating and ageing. The CGIC had significantly higher hardness but lower flexural strength than the RM-GIC and RC. © 2016 Australian Dental Association.

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.

Proton Resonance Spectroscopy in CALCIUM-40.

NASA Astrophysics Data System (ADS)

Warthen, Barry Joseph

1987-09-01

The differential cross sections for the ^{39}K(p,p_{ rm o})^{39}K and ^{39}K(p,alpha_ {rm o})^{36}Ar reactions have been measured for E_{ rm p} = 1.90 to 4.02 MeV at laboratory angles theta = 90^ circ, 108^circ, 150^circ and 165^ circ. Data were taken with the Triangle Universities Nuclear Laboratory (TUNL) KN Van de Graaff accelerator and the associated high resolution system. The targets consisted of 1-2 mug/cm^2 of potassium carbonate (K_2CO _3), enriched to 99.97% ^{39}K, evaporated onto gold coated carbon backings. Excitation functions were measured in proton energy steps varying from 100 to 400 eV. The energy region studied corresponds to an excitation energy range in the ^{40}Ca nucleus of E_{rm x} = 10.2 to 12.3 MeV. A multi-level multi-channel R-matrix based computer code was used to fit the experimental excitation functions. Resonance parameters obtained include resonance energy, spin, parity, partial widths, and channel spin and orbital angular momentum mixing ratios. Of the 248 resonances observed in the proton channel, 148 were also observed in the alpha channel. A fit to the observed level density yielded a nuclear temperature of 1.5 MeV. The data were compared with predictions of statistical theories of energy levels for both level spacing and reduced width distributions. The alpha reduced widths agree with the Porter-Thomas distribution and suggest that only 5-10% of the states with alpha widths were not observed. The summed strength in each of the alpha channels represents a significant fraction of the Wigner limit for these channels. The proton channels, on the other hand, generally have much smaller fractions. The two proton s-wave strength functions are equal and thus show no evidence for spin-exchange forces in the nucleon-nucleus interaction.

Muscle activation when performing the chest press and shoulder press on a stable bench vs. a Swiss ball.

PubMed

Uribe, Brandon P; Coburn, Jared W; Brown, Lee E; Judelson, Daniel A; Khamoui, Andy V; Nguyen, Diamond

2010-04-01

The aim of this study was to examine the effects of a stable surface (bench) vs. an unstable surface (Swiss ball) on muscle activation when performing the dumbbell chest press and shoulder press. Sixteen healthy men (24.19 +/- 2.17 years) performed 1 repetition maximum (1RM) tests for the chest press and shoulder press on a stable surface. A minimum of 48 hours post 1RM, subjects returned to perform 3 consecutive repetitions each of the chest press and shoulder press at 80% 1RM under 4 different randomized conditions (chest press on bench, chest press on Swiss ball, shoulder press on bench, shoulder press on Swiss ball). Electromyography was used to assess muscle activation of the anterior deltoid, pectoralis major, and rectus abdominus. The results revealed no significant difference in muscle activation between surface types for either exercise. This suggests that using an unstable surface neither improves nor impairs muscle activation under the current conditions. Coaches and other practitioners can expect similar muscle activation when using a Swiss ball vs. a bench.

Effect of Bench Press Load Knowledge on Repetitions, Rating of Perceived Exertion, and Attentional Focus.

PubMed

Beaudoin, Christina M; Cox, Zachary; Dundore, Tyler; Thomas, Tayler; Kim, Johnathon; Pillivant, Daniel

2018-02-01

Beaudoin, CM, Cox, Z, Dundore, T, Thomas, T, Kim, J, and Pillivant, D. Effect of bench press load knowledge on repetitions, rating of perceived exertion, and attentional focus. J Strength Cond Res 32(2): 514-519, 2018-Few studies have examined the role of the teleoanticipation during resistance training. The purpose of this study was to examine the effect of bench press (BP) load knowledge on repetitions completed, ratings of perceived exertion (RPEs), and attentional focus (% associative). Thirty-six recreationally active resistance-trained men (n = 25) and women (n = 11) participated in this study (age = 20.97 ± 1.87 years; ht = 174.12 ± 9.41 cm; and mass = 80.14 ± 14.03 kg). All subjects completed 3 testing sessions: (a) 1 repetition maximum (1RM) BP determination; (b) submaximal BP repetitions to fatigue known load (KL); and (c) submaximal BP repetitions to fatigue unknown load (UL). Known load and UL sessions were randomized and counterbalanced and both completed at 70% 1RM. An estimated weight ratio was computed using the subject's estimate of the UL weight relative to the KL weight. An independent samples t-test revealed no significant testing order difference for the estimated weight ratio. Two-way repeated-measures analysis of variances revealed no significant differences in the number of repetitions (p = 0.63), RPE (p = 0.18), or attentional focus (% associative) (p = 0.93) between the KL and UL conditions. Pearson correlations found a moderate positive association between KL repetitions completed and % associative focus when the UL was completed before the KL. Load knowledge did not influence the number of repetitions, RPE, or attentional focus while completing the BP. Further research examining the use of pacing strategies, RPE, and attentional focus during KL and UL conditions are warranted.

The Reliability of Individualized Load-Velocity Profiles.

PubMed

Banyard, Harry G; Nosaka, K; Vernon, Alex D; Haff, G Gregory

2017-11-15

This study examined the reliability of peak velocity (PV), mean propulsive velocity (MPV), and mean velocity (MV) in the development of load-velocity profiles (LVP) in the full depth free-weight back squat performed with maximal concentric effort. Eighteen resistance-trained men performed a baseline one-repetition maximum (1RM) back squat trial and three subsequent 1RM trials used for reliability analyses, with 48-hours interval between trials. 1RM trials comprised lifts from six relative loads including 20, 40, 60, 80, 90, and 100% 1RM. Individualized LVPs for PV, MPV, or MV were derived from loads that were highly reliable based on the following criteria: intra-class correlation coefficient (ICC) >0.70, coefficient of variation (CV) ≤10%, and Cohen's d effect size (ES) <0.60. PV was highly reliable at all six loads. Importantly, MPV and MV were highly reliable at 20, 40, 60, 80 and 90% but not 100% 1RM (MPV: ICC=0.66, CV=18.0%, ES=0.10, standard error of the estimate [SEM]=0.04m·s -1 ; MV: ICC=0.55, CV=19.4%, ES=0.08, SEM=0.04m·s -1 ). When considering the reliable ranges, almost perfect correlations were observed for LVPs derived from PV 20-100% (r=0.91-0.93), MPV 20-90% (r=0.92-0.94) and MV 20-90% (r=0.94-0.95). Furthermore, the LVPs were not significantly different (p>0.05) between trials, movement velocities, or between linear regression versus second order polynomial fits. PV 20-100% , MPV 20-90% , and MV 20-90% are reliable and can be utilized to develop LVPs using linear regression. Conceptually, LVPs can be used to monitor changes in movement velocity and employed as a method for adjusting sessional training loads according to daily readiness.

Development of an Integrated Countermeasure Device for Use in Long-Duration Space Flight

NASA Technical Reports Server (NTRS)

Streeper, Tim; Cavanagh, Peter R.; Hanson, Andrea M.; Carpenter, Dana; Saeed, Isra; Kornak, John; Frassetto, Lynda; Grodsinsky, Carlos; Funk, Justin; Lee, Stuart M. C.;

The development, retention and decay rates of strength and power in elite rugby union, rugby league and American football: a systematic review.

PubMed

McMaster, Daniel Travis; Gill, Nicholas; Cronin, John; McGuigan, Michael

2013-05-01

Strength and power are crucial components to excelling in all contact sports; and understanding how a player's strength and power levels fluctuate in response to various resistance training loads is of great interest, as it will inevitably dictate the loading parameters throughout a competitive season. This is a systematic review of training, maintenance and detraining studies, focusing on the development, retention and decay rates of strength and power measures in elite rugby union, rugby league and American football players. A literature search using MEDLINE, EBSCO Host, Google Scholar, IngentaConnect, Ovid LWW, ProQuest Central, ScienceDirect Journals, SPORTDiscus and Wiley InterScience was conducted. References were also identified from other review articles and relevant textbooks. From 300 articles, 27 met the inclusion criteria and were retained for further analysis. STUDY QUALITY: Study quality was assessed via a modified 20-point scale created to evaluate research conducted in athletic-based training environments. The mean ± standard deviation (SD) quality rating of the included studies was 16.2 ± 1.9; the rating system revealed that the quality of future studies can be improved by randomly allocating subjects to training groups, providing greater description and detail of the interventions, and including control groups where possible. Percent change, effect size (ES = [Post-Xmean - Pre-Xmean)/Pre-SD) calculations and SDs were used to assess the magnitude and spread of strength and power changes in the included studies. The studies were grouped according to (1) mean intensity relative volume (IRV = sets × repetitions × intensity; (2) weekly training frequency per muscle group; and (3) detraining duration. IRV is the product of the number of sets, repetitions and intensity performed during a training set and session. The effects of weekly training frequencies were assessed by normalizing the percent change values to represent the weekly changes in strength and power. During the IRV analysis, the percent change values were normalized to represent the percent change per training session. The long-term periodized training effects (12, 24 and 48 months) on strength and power were also investigated. Across the 27 studies (n = 1,015), 234 percent change and 230 ES calculations were performed. IRVs of 11-30 (i.e., 3-6 sets of 4-10 repetitions at 74-88% one-repetition maximum [1RM]) elicited strength and power increases of 0.42% and 0.07% per training session, respectively. The following weekly strength changes were observed for two, three and four training sessions per muscle region/week: 0.9%, 1.8 % and 1.3 %, respectively. Similarly, the weekly power changes for two, three and four training sessions per muscle group/week were 0.1%, 0.3% and 0.7 %, respectively. Mean decreases of 14.5% (ES = -0.64) and 0.4 (ES = -0.10) were observed in strength and power across mean detraining periods of 7.2 ± 5.8 and 7.6 ± 5.1 weeks, respectively. The long-term training studies found strength increases of 7.1 ± 1.0% (ES = 0.55), 8.5 ± 3.3% (ES = 0.81) and 12.5 ± 6.8% (ES = 1.39) over 12, 24 and 48 months, respectively; they also found power increases of 14.6% (ES = 1.30) and 12.2% (ES = 1.06) at 24 and 48 months. Based on current findings, training frequencies of two to four resistance training sessions per muscle group/week can be prescribed to develop upper and lower body strength and power. IRVs ranging from 11 to 30 (i.e., 3-6 sets of 4-10 repetitions of 70-88% 1RM) can be prescribed in a periodized manner to retain power and develop strength in the upper and lower body. Strength levels can be maintained for up to 3 weeks of detraining, but decay rates will increase thereafter (i.e. 5-16 weeks). The effect of explosive-ballistic training and detraining on pure power development and decay in elite rugby and American football players remain inconclusive. The long-term effects of periodized resistance training programmes on strength and power seem to follow the law of diminishing returns, as training exposure increases beyond 12-24 months, adaptation rates are reduced.