The purpose of this research was to investigate the effects of eccentric phase
duration on concentric outcomes at 60% and 80% of one-repetition maximum (1RM) in
the squat and bench press. Sixteen resistance-trained males completed four laboratory
visits as follows: Day 1- 1RM testing; Day 2- establishment of normative eccentric
durations; Days 3 and 4- randomized fast (0.75 times) or slow (2 times) eccentric
duration variations, which were controlled by visual and auditory metronomes. Eccentric
duration was significantly and inversely correlated with average concentric velocity
(ACV) at 60% (r = 0.408) and 80% (r = -0.477) of 1RM squat and at 100% of 1RM
bench press. At 60% of 1RM squat, both fast and slow eccentric conditions produced
greater (p<0.001) peak concentric velocity (PCV) than normative duration with fast also
producing greater PCV than slow (p=0.044). Therefore, fast eccentric durations may
benefit concentric velocity.