ECCENTRIC MUSCLE ACTIONS PRODUCE 36% TO 154% LESS ACTIVATION THAN CONCENTRIC MUSCLE ACTIONS

This study evaluated the differences in eccentric and concentric phase muscle activation of variety of muscles during lower body resistance training exercises. Surface electromyography data (EMG) from 12 subjects was analyzed for the eccentric and concentric phases of the squat, deadlift, step-up, and lunge. Data from the test exercises were averaged for the eccentric and concentric phase for each muscle group to produce a comprehensive measure of activation differences between the eccentric and concentric phases. A paired samples t-test revealed differences between eccentric and concentric phase activation for all muscles assessed (p ≤ 0.05). Results demonstrated that during lower body multi-joint exercises the eccentric phase produced 36% to 154% less muscle activation that the concentric phase.