Differences In Power And Velocity During The Back Squat In Resistance-trained Men And Women.

Abstract

Muscular power is vital to success across sport and competitive level. Determination of the load that optimizes power varies by exercise, gender, and training status. For example, the load that maximized peak power for the power clean in men has been proposed to occur at 80% one-repetition maximum (1RM); whereas the ideal load for the squat is equivocal. Further, one study reported differences between men and women in peak power at differing loads during ballistic exercise. However, few data exist on the differences in men and women relative to power and velocity, and no study has examined the squat, a primary exercise for lower body power development. PURPOSE: To determine whether differences exist between resistance-trained (RT) men and women in regard to the loads that maximize average power (AP), peak power (PP), average velocity (AV), and peak velocity (PV) in the back squat (BS). METHODS: Forty-one RT (n = 41) men (m = 20; 21 ± 1 y; 183.0 ± 7.8 cm; 82.5 ± 8.0 kg) and women (w = 21; 20 ± 1 y; 166.5 ± 6.9 cm; 63.1 ± 7.7 kg) had their 1RM determined (m: 147.0 ± 28.0 kg; f: 89.1 ± 12.3 kg). On a second day, they performed two repetitions at BS loads corresponding to 30%, 40%, 50%, 60%, 70%, 80%, and 90% 1RM as explosively as possible for determination of AV, PV, AP and PP. The repetition with the highest value was used for comparison. Repeated measures analysis of variance for AV, PV, AP, and PP were run. RESULTS: Men were older (p = 0.022), taller (p < 0.001), heavier (p < 0.001), stronger (p < 0.001), and had a greater 1RM to body weight ratio (m: 1.8 ± 0.3; w: 1.4 ± 0.1; p < 0.001). Men also produced higher velocities (PV, AV) and power (PP, AP) across all loads. The highest PP occurred at 90%1RM for both, though no difference was noted between 80%1RM and 90%1RM in either sex. The highest AP occurred at 70%1RM in men, though AP at 60% and 80%1RM were not different. The highest AP in women was observed at 80%1RM, though no difference was noted between that intensity and 50% - 70%RM. AV and PV occurred at the lowest intensity (30%1RM) in both sexes. CONCLUSION: These data suggest that load for PP, PV, and AV does not differ. However, differences did exist in the load that resulted in the highest AP. Whether this would be observed across all sports is unknown. Further study is required to determine if sex differences exist in load among different sports and training status.