HAMSTRING ELECTROMYOGRAPHIC RESPONSE OF THE BACK SQUAT AT DIFFERENT KNEE ANGLES DURING CONCENTRIC AND ECCENTRIC PHASES

Abstract

This study examined mean I-EMG for the hamstring group, during eccentric vs. concentric phases of the back squat at knee angles of 160-150, 140-130, 120-110 and 100-90. A 2X4 Repeated Measures ANOVA of the I-EMG hamstring activity revealed a significant interaction of contraction phase by angle (p<.05), but not for main effects of contraction phase or angle (p>.05). Closer analysis of each contraction phase via a One-way (angle) Repeated Measures ANOVA showed hamstring I-EMG during the eccentric contraction at 120-110 and 100-90 to be greater than 160-150 (p<.05), but not different from 140-130 (p>.05). In addition, there was no difference between 160-150 and 140-130 during the eccentric phase (p>.05). Furthermore, there were no differences found between mean I-EMG activity for any of the angles during concentric knee extension (p>.05).