Squat-based post-activation potentiation improves the vertical jump of elite female volleyball players

The purpose of this study was to confirm if a squat-based conditioning activity was effective in generating post-activation potentiation (PAP), and, as a consequence of this activation, improve the vertical jump (VJ) performance of national female volleyball players. Eleven trained volleyball players (22.6 ± 3.5 years) were randomly divided into two groups: an experimental group (N=6) and a control group (N=5). They completed 2 sessions. In the first session, a back squat one-repetition maximum (1RM) was determined for the experimental group by using an optoelectronic encoder and an incremental protocol until reaching the maximum load lifted for each subject. On the second day, the experimental group performed a PAP procedure consisting of three repetitions of 90% of 1RM. Before and after performing the activation protocol, both groups completed a countermovement jump (CMJ) to verify whether any improvements were accomplished in the VJ. The height of the vertical jump was estimated by using a jump mat. The data obtained were analysed using an ANOVA test to determine the significant differences intra-group and between groups. The pre-PAP test did not establish any differences between the results of the control group (31.35±4.28 cm) and that of the experimental group (34.08±3.98cm), Therefore, the groups were, at first, homogeneous. On the other hand, there were significant differences in the CMJ percentage of improvement between the experimental and control groups in the post-PAP test F(1,9)=6.074; p=0.036; ▢2=0.40. The control group presented a loss in jump height in the CMJ, thus obtaining negative values in the improvement percentage (-5.36%). The experimental group improved its jump height (4.11%). These differences between groups were statistically significant F(1,9)=6.673; p=0.030; ▢2=0.43. Finally, no significant differences were found intragroup between the pre and post-PAP test in both groups. To conclude, squat-based PAP protocols can generate positive effects on the vertical jump performance of elite female volleyball players. It may therefore be relevant to introduce these activation methods in the warm-up protocols of volleyball players.This study was supported by a pre-doctoral grant (ACIF/2018/209) from the Generalitat Valenciana, Spain, and vice-rectorate program of research and knowledge transfer for the promotion of R+D+I at the University of Alicante (Ref. GRE18-19)