Impact of Accommodating Resistance in Potentiating Horizontal-Jump Performance in Professional Rugby League Players.

Abstract

This study investigated the efficacy of deadlifts and box squats, with a combination of traditional and accommodating resistance, as a postactivation potentiating stimulus of standing broad jumps (SBJ) in a multiple-set contrast protocol. Twelve professional rugby league players (21.4 [2.5]y; 181.3 [8.3]cm, 91.9 [8.8]kg; 1-repetition-maximum [1RM] back squat/body mass 1.59 [0.21]; 1RM deadlift/body mass 2.11 [0.25]; ≥3-y resistance-training experience) performed baseline SBJ before a contrast postactivation potentiating protocol involving 2 repetitions of 85% 1RM box squat or deadlifts, loaded with a combination of traditional barbell weight (70% 1RM) and elastic-band resistance (∼15% 1RM), followed by 2 SBJs. Exercises were separated by 90 s, and 4 contrast pairs were performed in total. Using a repeated-measures design, all subjects performed the squat followed by the deadlift and finally the control (SBJ only) condition in the same order across consecutive weeks. Changes from baseline in SBJ distance were moderate for the box squat (effect size [ES] = 0.64-1.03) and deadlift (ES = 0.80-0.96) and trivial in the control condition (ES = 0.02-0.11). The magnitude of differences in postactivation potentiating effect were considered moderate (d = 0.61) for set 1, trivial for set 2 (d = 0.10) and set 3 (d = 0.05) in favor of box squats, and moderate for set 4 (d = 0.58) in favor of deadlifts. Accommodating resistance in either box squats or deadlifts is an effective means of potentiating SBJ performance across multiple sets of a contrast protocol with only 90-s rest.