| The purpose of this study was to investigate the effects of heavy deadlifts on vertical jump performance. Fifteen experienced men (age, 23.9 +/- 4.2 years; height, 176.3 +/- 8.6 cm; mass, 76.1 +/- 16.3 kg) participated in the study. Participants completed three testing sessions each separated by at least 48 hours. On the first testing session, height, weight, and one repetition max (1-RM) in the deadlift was collected. Subjects then performed one of two experimental sessions in a random order and counter-balanced design: a control session (no deadlift) and a deadlift (5 repetition using 85% 1-RM). On each day, subjects began with a dynamic warm-up, followed by a five minute rest, then performed a single maximal counter-movement jump without an arm swing (CMJ), then either performed five repetitions of the deadlift using 85% of their 1-RM or were told to stand still for ten seconds (control). Following either condition, subjects performed a single CMJ at the following intervals: 15 seconds, 2, 4, 6, 8, 10, 12, 14, and 16 minutes post condition. Peak vertical jump (VJ) height and peak ground reaction forces (GRF) were measured using a force plate. Two separate 2 x 10 (condition x time) repeated measures ANOVAs were used to assess VJ height and peak GRF. Results showed that for the deadlift condition, there was a significant (p < 0.05) negative effect on VJ height immediately following lifting. Performance of five repetitions of deadlifting did not affect GRF. Rest duration may have influenced the fatigue vs. potentiating effects. We speculate that if longer rest durations were given following the stimulus, subjects may have exhibited a potentiating effect or overcome the effects of fatigue. |
