The purpose of this study was to evaluate the difference between positions for absolute and relative isokinetic leg flexion and extension strength as well as ipsilateral and bilateral ratios of NCAA Division II university football players. Fifty-five players (19.8 ± 1.4 years) volunteered to be measured using a Cybex IP dynamometer at 180 and 300°/sec. The players were grouped into four positions: offensive backs and receivers (OB), offensive linemen (OL), defensive linemen (DL), and defensive backs (DB). One-way ANOVA with Scheffe post hoc comparisons indicated that for absolute flexion and extension strength the linemen (OL and DL) tended to be stronger than the backs (06 and DB); however, these relationships were reversed (backs were stronger than linemen) when differences in body weight were considered (peak torque/body weight). There were no significant (p < 0.05) differences between positions for ipsilateral comparisons at 180 or 300°/sec. However, the magnitude of the ratio was specific to the speed of contraction. Significant differences between positions were found for bilateral strength ratios measured at 180°/sec; however, all values were within 7% of equity and therefore were of little physiological consequence.

J Orthop Sports Phys Ther 1988;9(11):365-369.

Previous studies have indicated an age effect in the strength of high school wrestlers. The purpose of this investigation was to quantify horizontal abduction and adduction strengths at the shoulder in high school wrestlers and to examine the age effect for these movements. Seventy-nine high school wrestlers (age = 16.28 ± 1.26 yrs) were stratified into four groups corresponding to the ages of the wrestlers during their freshman, sophomore, junior, and senior years. The subjects were tested for horizontal abduction and adduction strength at the shoulder at 30, 180, and 300°/sec. Body composition was determined from underwater weighing. The results of this study indicated that absolute peak torque and peak torque divided by body weight or fat-free weight increased across age at 30°/sec for abduction and adduction as well as at 180°/sec for adduction. No significant differences in absolute or relative strength across age were noted at 180°/sec for abduction or at 300°/sec for abduction and adduction. These results suggest an age effect for muscular strength development in high school wrestlers that is independent of increases in body weight and fat-free weight. In addition, these results provide normative data for comparisons with other athletes and nonathletes and may be used for assessing readiness to return to activity after in jury.

J Orthop Sports Phys Ther 1992;15(4):183-186.

Key Words: body composition, shoulder strength, wrestling

STUDY DESIGN: Repeated-measures experi­mental design. OBJECTIVE: To examine the acute effects of static stretching on peak torque, the joint angle at peak torque, mean power output, and electromyo­graphic and mechanomyographic amplitudes and mean power frequency of the vastus lateralis and rectus femoris muscles during maximal eccentric isokinetic muscle actions. BACKGROUND: A bout of static stretching may impair muscle strength during isometric and concentric muscle actions, but it is unclear how static stretching may affect eccentric force production. METHODS AND MEASURES: Fifteen men (mean 6 SD age, 23.4 6 2.4 years) performed maximal eccentric isokinetic muscle actions of the dominant and nondominant knee extensor muscles at 60°·s–1 and 180°·s–1 on an isokinetic dynamometer, while electromyographic and mech­anomyographic amplitudes (root-mean-square) and mean power frequency were calculated for the vastus lateralis and rectus femoris muscles. Peak torque (Nm), the joint angle at peak torque (°), and mean power output (W) values were recorded by the dynamometer. Subsequently, the dominant lower extremity knee extensors underwent static stretching exercises, then the assessments were repeated. RESULTS: There were no stretching-related changes in peak torque, the joint angle at peak torque, mean power output, electromyographic or mechanomyographic amplitude, or mean power frequency (P>.05). However, there were expected velocity-related, limb-related, and muscle-related differences (P≤.05) that were unrelated to the stretching intervention. CONCLUSION: These results suggest that static stretching does not affect maximal eccentric isokinetic torque or power production, nor does it change muscle activation.  

J Orthop Sports Phys Ther. 2007;37(3):130-139. doi:10.2519/jospt.2007.2389 

KEY WORDS: EMG, muscle activation, muscle stiffness, stretching-induced force deficit