The acute effect of a plyometric stimulus on jump performance in professional rugby players.

Post-activation potentiation (PAP) is the increase of motor output to a higher level in response to a conditioning stimulus. Extensive research exists examining the PAP effect following a heavy resistance exercise. Although, research examining the PAP effect following a plyometric stimulus is lacking. The authors designed this study to examine whether a plyometric stimulus could produce a PAP effect similar to that usually reported with a heavy resistance protocol. Notably, they hypothesized that the PAP effect would exist without the same levels of acute fatigue resulting from a heavy stimulus, thus allowing improvement in performance within a short rest interval range.

Twenty professional rugby players were recruited for the study. Subjects performed two countermovement jumps (CMJs) at baseline and at 1, 3 and 5 minutes after a plyometric stimulus consisting of 40 jumps. Two separate one-way repeated measures ANOVA were conducted to compare the dependent variables CMJ height and peak force at the four time points. Results of the bonferroni adjusted pairwise comparisons indicated that jump height and peak force pre-plyometric exercises, were significantly lower than all other time points (p < 0.01). The study’s primary finding suggests that a series of plyometric exercises causes a significant acute enhancement in CMJ height (p < 0.01) and peak force (p < 0.01) throughout the rest interval range of 1-5 minutes. The plyometric series induced an improvement in CMJ height comparable to that reported elsewhere following a heavy lifting stimulus but without the need for a prolonged rest interval. Performing repeated series of plyometric jumps appears to be an efficient method of taking advantage of the PAP phenomenon thus possibly eliminating the need for a complex training protocol.