Jerry L. Mayhew

The Accuracy of Prediction Equations for Estimating 1-rm Performance in the Bench Press, Squat, and Deadlift

This study was done to determine the accuracy of 7 equations for predicting a 1-RM from repetitions to fatigue for the bench press, squat, and deadlift. Subjects, 67 untrained college students (40 M, 27 F) who were enrolled in weight training classes, participated in four 45-min practice sessions to learn proper lifting technique and determine the amount of weight to lift for the 1-RM test. All correlation coefficients between predicted and achieved 1-RM lifts were high (r > 0.95). For the bench press, however, the average differences between achieved and predicted weights were significantly different from zero in all but 2 equations. For the squat, the average difference was significantly different from zero in all but 1 equation. All equations significantly underestimated the deadlift despite high correlations.

Effect of Compression Stockings on Running Performance in Men Runners

Kemmler, W, von Stengel, S, Köckritz, C, Mayhew, J, Wassermann, A, and Zapf, J. Effect of compression stockings on running performance in men runners. J Strength Cond Res 23(1): 101-105, 2009-The purpose of this study was to determine the effect of below-knee compression stockings on running performance in men runners. Using a within-group study design, 21 moderately trained athletes (39.3 ± 10.9 years) without lower-leg abnormities were randomly assigned to perform a stepwise treadmill test up to a voluntary maximum with and without below-knee compressive stockings. The second treadmill test was completed within 10 days of recovery. Maximum running performance was determined by time under load (minutes), work (kJ), and aerobic capacity (ml·kg−1·min−1). Velocity (km·h−1) and time under load were assessed at different metabolic thresholds using the Dickhuth et al. lactate threshold model. Time under load (36.44 vs. 35.03 minutes, effect size [ES]: 0.40) and total work (422 vs. 399 kJ, ES: 0.30) were significantly higher with compression stockings compared with running socks. However, only slight, nonsignificant differences were observed for &OV0312;o2max (53.3 vs. 52.2 ml·kg−1·min−1, ES: 0.18). Running performance at the anaerobic (minimum lactate + 1.5 mmol·L−1) threshold (14.11 vs. 13.90 km·h−1, ES: 0.22) and aerobic (minimum lactate + 0.5 mmol·L−1) thresholds (13.02 vs. 12.74 km·h−1, ES: 0.28) was significantly higher using compression stockings. Therefore, stockings with constant compression in the area of the calf muscle significantly improved running performance at different metabolic thresholds. However, the underlying mechanism was only partially explained by a slightly higher aerobic capacity.

Characteristics of sprint performance in college football players.

Brechue, WF, Mayhew, JL, and Piper, FC. Characteristics of sprint performance in college football players. J Strength Cond Res 24(5): 1169-1178, 2010-To investigate sprinting strategy, acceleration and velocity patterns were determined in college football players (n = 61) during performance of a 9.1-, 36.6-, and 54.9-m sprints. Acceleration and velocity were determined at 9.1-m intervals during each sprint. Lower-body strength and power were evaluated by 1 repetition maximum (1-RM) squat, power clean, jerk, vertical jump, standing long jump, and standing triple jump. Sprint times averaged 1.78 ± 0.11 seconds (9.1 m), 5.18 ± 0.35 seconds (36.6 m), and 7.40 ± 0.53 seconds. Acceleration peaked at 9.1 m (2.96 ± 0.44 m·s−2), was held constant at 18.3 m (3.55 ± 0.0.94 m·s−2), and was negative at 27.4 m (−1.02 ± 0.72 m·s−2). Velocity peaked at 18.3 m (8.38 ± 0.65 m·s−1) and decreased slightly, but significantly at 27.4 m (7.55 ± 0.66 m·s−1), associated with the negative acceleration. Measures of lower-body strength were significantly related to acceleration, velocity, and sprint performance only when corrected for body mass. Lower-body strength/BM and power correlated highest with 36.6-m time (rs = −0.55 to −0.80) and with acceleration (strength r = 0.67-0.49; power r = 0.73-0.81) and velocity (strength r = 0.68-0.53; power r = 0.74-0.82) at 9.1 m. Sprint times and strength per body mass were significantly lower in lineman compared with linebackers-tight ends and backs. The acceleration and velocity patterns were the same for each position group, and differences in sprint time were determined by the magnitude of acceleration and velocity at 9.1 and 18.3 m. Sprint performance in football players is determined by a rapid increase in acceleration (through 18.3 m) and a high velocity maintained throughout the sprint and is independent of position played. The best sprint performances (independent of sprint distance) appear to be related to the highest initial acceleration (through 18.3 m) and highest attained and maintained velocity. Strength relative to body mass and power appears to impact initial acceleration and velocity (through 18.3 m) in contribution to sprint performance.

Electromyographic activity of the pectoralis major and anterior deltoid muscles during three upper-body lifts.

The purpose of this study was to examine the differences in activation levels and times of activation for the pectoralis major and anterior deltoid when performing the concentric phase of 3 upper-body lifts. Twelve college-age men and women with various degrees of lifting experience performed 3 repetitions using the 6 repetition maximum in a barbell bench press, dumbbell bench press, and dumbbell fly while being monitored for electromyographic activity in both muscles. Motor unit activation of both muscles was not significantly different during all 3 lifts. However, dumbbell flys had significantly less relative time of activation than did barbell or dumbbell bench presses. Therefore, dumbbell flys may be better suited as an auxiliary lift, whereas barbell and dumbbell bench presses may be used interchangeably in training programs. The compatibility of the barbell and dumbbell bench presses may aid lifters in overcoming training plateaus by alternating exercises for the same muscle groups.

Exercise, Body Composition, and Functional Ability: A Randomized Controlled Trial

CONTEXT In women, age and the menopausal transition contribute to an increase of body fat and a reduction of lean body mass associated with functional decline, affecting independent living. BACKGROUND Sarcopenia and adiposity in the elderly has been associated with increased mortality and functional decline affecting independent living. PURPOSE This study was conducted to determine the effect of a multipurpose exercise program on the body composition and functional ability of elderly women living in a community. DESIGN An 18-month single-blinded RCT comparing participants in an exercise program with an active control group was conducted from May 2005 through December 2007. Analyses were conducted from January 2008 to July 2008. SETTING/PARTICIPANTS Two hundred forty-six women (aged 69.1+/-4.0 years) living independently in the area of Erlangen-Nürnberg (Germany) participated in the study. INTERVENTION Subjects (n=123) performed a multipurpose exercise program with special emphasis on exercise intensity but with low-level requirements for training facilities and materials. The 123 women in the control group focused primarily on well-being. MAIN OUTCOME MEASURES Body composition was assessed by dual-energy x-ray absorptiometry. Further, strength was evaluated using isometric techniques for the back and legs. Aerobic fitness was determined from a progressive-intensity treadmill test. RESULTS After 18 months, significant effects in favor of the exercise program for body composition were increases in appendicular skeletal muscle mass and lean body mass along with reductions in abdominal fat and total body fat. Significant performance effects also favored the exercise program and included enhanced isometric maximum trunk-extensor and leg press strength, leg press power, timed up-and-go test, and aerobic fitness. CONCLUSIONS A high-intensity multipurpose exercise program produced significant improvements in body composition and functional ability in a cohort of elderly women living in a community.

ACCURACY OF PREDICTION EQUATIONS FOR DETERMINING ONE REPETITION MAXIMUM BENCH PRESS IN WOMEN BEFORE AND AFTER RESISTANCE TRAINING

Mayhew, JL, Johnson, BD, LaMonte, MJ, Lauber, D, and Kemmler, W. Accuracy of prediction equations for determining one repetition maximum bench press in women before and after resistance training. J Strength Cond Res 22(5): 1570-1577, 2008-Repetitions to fatigue (RTF) using less than a 1 repetition maximum (1RM) load (RepWt) have been shown to be a good predictor of 1RM strength in men, but such information is scarce in women. The purpose of this study was to evaluate the accuracy of current prediction equations to estimate 1RM bench press performance and to determine whether resistance training changes the capability to predict 1RM from muscular endurance repetitions in young women. Members (n = 103) of a required wellness course were measured for 1RM bench press and RTF using randomly assigned percentages between 60% and 90% of the 1RM (RepWt) before and after 12 weeks of progressive resistance training. The %1RM used to perform RTF remained the same for each individual after training (75.6% ± 10.3%) as before. One repetition maximum bench press increased significantly after training (28% ± 21%). Although the change in the group average for RTF (0.6 ± 6.1) was not significant, the correlation between pretraining and posttraining RTF was moderate (r = 0.66; p < 0.01), and individual differences in percentage change in RTF were substantial (27% ± 99%). The percentage change in 1RM was not significantly related to initial 1RM (r = −0.05), but it was negatively related to the change in RTF (r = −0.40; p < 0.01). Prediction equations were more accurate in the pretraining and posttraining conditions, in which fewer than 10 RTF were used. Resistance training may alter the relationship between strength and muscle endurance across a wide range of RTF in young women without compromising the accuracy of predicting maximal strength.

Familiarization and reliability of one repetition maximum strength testing in older women.

Abstract Amarante do Nascimento, M, Januário, RSB, Gerage, AM, Mayhew, JL, Cheche Pina, FL, and Cyrino, ES. Familiarization and Reliability of one repetition maximum Strength Testing in Older Women. J Strength Cond Res 27(6): 1636–1642, 2013—Strength is a fundamental component of physical fitness, and therefore should be precisely assessed. The purpose of this study was to analyze the number of testing sessions required to achieve consistent 1 repetition maximum (1RM) strength measurements in untrained older women. Forty-five untrained older women were measured for 1RM in bench press machine (BP), leg extension (LE) machine, and free weight arm curl (AC). Reliability coefficients for trials 1 and 2 for BP (intraclass correlation coefficient [ICC] = 0.973) and LE (ICC = 0.976) were higher than for AC (ICC = 0.953). Percent change from trial 1 to 2 for BP (3.5 ± 10.9%) and AC (3.8 ± 8.1%) was less than for LE (5.4 ± 6.2%), but all were significant increases between trials (p < 0.05). Trial differences were reduced to nonsignificant levels (p > 0.05) in the third trial for BP (0.0 ± 0.0%), LE (1.2 ± 3.0%) and AC (2.7 ± 5.9%). Reliability coefficients rose for BP and LE (ICC = 0.999) and AC (ICC = 0.963) when a third trial was performed. Bland and Altman plotting showed very small bias and limits of agreement (LoA) for both the exercises (BP: bias = 0 kg, limits of agreement = 0 kg; LE: bias = −0.16 kg, LoA = 2.21 kg; AC: bias = −0.11 kg, LoA = 1.72 kg). This approach to determine 1RM strength values produced rapid lifting technique familiarization resulting in a need of 2 to 3 test sessions to achieve consistent 1RM measurements in untrained older women.

Effects of Whole-body Electromyostimulation on Resting Metabolic Rate, Body Composition, and Maximum Strength in Postmenopausal Women: the Training and Electrostimulation Trial

Kemmler, W, Schliffka, R, Mayhew, JL, and von Stengel, S. Effects of whole-body electromyostimulation on resting metabolic rate, body composition, and maximum strength in postmenopausal women: the Training and ElectroStimulation Trial. J Strength Cond Res 24(7): 1880-1887, 2010-We evaluated the effect of whole-body electromyostimulation (WB-EMS) during dynamic exercises over 14 weeks on anthropometric, physiological, and muscular parameters in postmenopausal women. Thirty women (64.5 ± 5.5 years) with experience in physical training (>3 years) were randomly assigned either to a control group (CON, n = 15) that maintained their general training program (2 × 60 min·wk−1 of endurance and dynamic strength exercise) or to an electromyostimulation group (WB-EMS, n = 15) that additionally performed a 20-minute WB-EMS training (2 × 20 min·10 d−1). Resting metabolic rate (RMR) determined from spirometry was selected to indicate muscle mass. In addition, body circumferences, subcutaneous skinfolds, strength, power, and dropout and adherence values. Resting metabolic rate was maintained in WB-EMS (−0.1 ± 4.8 kcal·h−1) and decreased in CON (−3.2±5.2 kcal·h−1, p = 0.038); although group differences were not significant (p = 0.095), there was a moderately strong effect size (ES = 0.62). Sum of skinfolds (28.6%) and waist circumference (22.3%) significantly decreased in WB-EMS whereas both parameters (1.4 and 0.1%, respectively) increased in CON (p = 0.001, ES = 1.37 and 1.64, respectively), whereas both parameters increased in CON (1.4 and 0.1%, respectively). Isometric strength changes of the trunk extensors and leg extensors differed significantly (p ≤ 0.006) between WB-EMS and CON (9.9% vs. −6.4%, ES = 1.53; 9.6% vs. −4.5%, ES = 1.43, respectively). In summary, adjunct WB-EMS training significantly exceeds the effect of isolated endurance and resistance type exercise on fitness and fatness parameters. Further, we conclude that for elderly subjects unable or unwilling to perform dynamic strength exercises, electromyostimulation may be a smooth alternative to maintain lean body mass, strength, and power.

Comparison Between Hand and Electronic Timing of 40-yd Dash Performance in College Football Players

Mayhew, JL, Houser, JJ, Briney, BB, Williams, TB, Piper, FC, and Brechue, WF. Comparison between hand and electronic timing of 40-yd dash performance in college football players. J Strength Cond Res 24(2): 447-451, 2010-The purpose of this study was to determine the difference between hand and electronic timing of 40-yd dashes in college football players. National Collegiate Athletic Association Division II players (n = 59) were measured during a 40-yd sprint by electronic timing and simultaneously by 7 experienced hand timers using digital stopwatches. Electronic times were initiated by lifting the hand from a switch mat and stopped by the torso passing through an infrared beam. Hand timers initiated timing on first movement of the player from a 3-point stance. To establish performance and timing reliabilities, 32 players completed a second trial. Interrater reliability for hand timing was intraclass correlation coefficient (ICC) = 0.987 (p < 0.001). Five of the 7 timers did not differ significantly (p > 0.05) in their timing. The maximum difference among the hand timers on any given trial was 0.19 ± 0.14 seconds, with a 95% confidence interval (CI) of −0.08 to 0.41 seconds. Hand timing (4.85 ± 0.28 seconds) was significantly faster (p < 0.001) than electronic timing (5.16 ± 0.28 seconds), producing an average difference of 0.31 ± 0.07 seconds (6.0 ± 1.3%) and a 95% CI on the average difference of −0.44 to −0.18 seconds. The correlation between electronic timing and hand timing was ICC = 0.985 (p < 0.001). Practically speaking, electronic timing produces the best measurement of 40-yd dash speed, and using the hand timing produces consistently but significantly faster times.

Prediction of bench press lifting ability from submaximal repetitions before and after training

The purpose of this study was to determine the accuracy of predicting maximal bench press lifting strength from submaximal bench press repetitions before and after a training program. College students (70 men; 101 women) were tested to determine their one repetition maximum (1‐RM) bench press lifting strength before and after 14 weeks of training. Several days after an initial maximum lift determination, each subject was randomly assigned a submaximal load corresponding to 55 to 95% of the 1‐RM and required to perform as many bench press repetitions as possible in 1 minute. The same percent 1‐RM was used following training, as was used before training, to test lifting capacity at a defined percent of the initial 1‐RM for a given individual. Men had a significantly greater 1‐RM bench press strength and absolute integrated submaximal weightlifting ability than women but were not significantly different in percent 1‐RM and repetitions. The exponential relationship between percent 1‐RM and repetitions before ...