Effects of a heavy resistance conditioning activity on post-activation potentiation and subsequent drop jump performance

Abstract

This investigation was conducted to examine the extent to which a low volume heavy resistance conditioning activity could induce post-activation potentiation, and consequently augment the performance of subsequent drop jumps completed over a 30 min recovery period. Thirteen male, national league rugby players performed drop jumps at baseline, 15 s, 10, 20, and 30 min following completion of one set of a three-repetition maximum back squat exercise. All drop jumps were performed from a 40 cm plyometric box onto a portable force platform (1000 Hz) which determined reactive strength index, ground contact time (s) and maximum jump height (m). Means and standard deviations for all variables were calculated and compared with baseline drop jump values. A repeated-measures one-way analysis of variance was employed to test for statistical significance (P < 0.05), and revealed that significant changes occurred in reactive strength index, ground contact time and maximum jump height during drop jumps performed throughout the 30 min recovery period. Furthermore, a Tukey Honestly Significant Difference post hoc test revealed significant improvement in reactive strength index (12.51%), and a positive but non-significant change in ground contact time (3.59%) and maximum jump height (10.10%) between drop jumps performed at baseline and 15 s post conditioning activity. However, little or no improvement in performance was recognised during the remainder of the 30 min recovery period. It was concluded that employment of a low volume heavy resistance conditioning activity had potential post-activation potentiation benefits for drop jumps performed following 15 s recovery period, but following longer recovery periods, the conditioning activity may in fact be detrimental to performance.