The relationship between load and elasticity in the power squat

The purpose of this study was to examine the relationship between load and musculoskeletal elasticity in the power squat. Eight male subjects experienced in the power squat participated in this study (mean height: 1.756±0.072 m; mean mass: 77.5±10.4 kg). Subjects were videotaped performing a countermovement squat (CMS) and a purely concentric squat (PCS). Both the CMS and PCS were performed at four load percentages (40%, 55%, 70%, and 85%) of the subject's tested one repetition maximum (mean maxima1 166.9±51.9 kg). Segmental data were digitized, reduced to selected mechanical variables, and analyzed with repeated measures ANOVAs (a=0.05). Results for concentric time indicated significant main effects for condition (CMS or PCS) and load percentage and a significant interaction between condition and load. Lifters required greater amounts of concentric time in the PCS and at higher loads. The interaction indicated that the subjects required exponentially greater amounts of time at heavier PCS loads than heavier CMS loads. Average concentric work and average concentric power had significant main effects for both condition and load percentage; average work and power were greater in the CMS condition and less at the heaviest load. A significant main effect for load percentage was found for maximum concentric velocity, net concentric work on the system, and energy; velocities decreased with increased relative loads; network increased as load percentage increased; and energy increased with increasing load