Introduction:
A countermovement jump (CMJ) is a common explosive activity used to measure lower body power. Determining an optimal rest interval may be beneficial in creating a training program to improve performance.

Aim of the study:
To investigate the post-activation potentiation (PAP) effect of different low-load, high-intensity CMJs on subsequent bodyweight CMJs.

Material and methods:
On four different occasions, eighteen athletes (age:19.61±0.98y; height: 177.69±11.35cm; mass: 80.22±11.96kg) completed one baseline CMJ followed by a series of low-load, high-intensity CMJs (0%, 10%, and 20% of their back squat one-repetition maximum [1RM]) and one control condition without a CMJ (NJ). For each low-load intervention, participants completed 1 set of 6 CMJs, except NJ where participants stood for 20-seconds. Then, participants performed single CMJs at 8 different rest intervals following the experimental and control conditions. Three, 4 x 9 (condition [NJ, 0%, 10%, and 20%] x time [baseline, 0.5-min, 1-min, 2-min, 4-min, 6-min, 8-min, 10-min, and 12-min,]) and three, 4 × 2 (condition x time [baseline and peak]) repeated measures analysis of variance were used to analyze jump height (JH), estimated power (eP), and flight time (FT) via a jump mat.

Results:
There were no protocol×time interactions. However, there was a significant (p<0.05) main effect for time for FT, where FT was longer at 2-min than 10-min, and FT was longer at 4-min than 8-, 10-, and 12-min. Peak JH, eP, and FT values were all significantly greater than baseline.

Conclusions:
A single warm-up jump may enhance jump performance and other low-loads investigated in this study. The effectiveness of a low-load PAP response may be highly dependent upon the individuals. Thus, a greater focus on individualized PAP programming is needed.