The acute effects of an ascending squat protocol on performance during horizontal plyometric jumps.

The purpose of the present investigation was to examine the effects of a strength-power potentiation complex that involved performing a horizontal plyometric activity 5 minutes after the completion of an ascending back squat protocol. Twelve men who could back squat a minimum of 1.5 time body mass participated in a familiarization session and 2 randomly assigned testing sessions each separated by approximately 1 week. In the control session, the subject rested for 5 minutes and then performed the horizontal plyometric tests. In the potentiation session (POT), the subjects performed an ascending back squat protocol that consisted of 5 repetitions at 30% of 1 repetition maximum (1RM), 3 repetitions at 70% 1RM, and 3 repetitions at 90% 1RM. Five minutes after completing the ascending back squat protocol, the subjects undertook the horizontal plyometric test, which consisted of jumping over 5 hurdles that were separated by 45.7 cm and were set to a height of 65.2 +/- 4.0 cm. An accelerometer was used to assess peak power output (PP), velocity (PV), and force (PF) across the 5 jumps. The average PF generated across the 5 hurdles was significantly higher in the POT session (p = 0.01, d = 0.45). In addition, the maximum PP output (p = 0.05, d = 1.12) and PF (p = 0.004, d = 0.61) were higher in the POT trials. Individuals who were able to back squat approximately 2.0 +/- 0.1 times body mass exhibited a greater percent potentiation for average PP output (p = 0.001, eta = 0.68) and average PV (p = 0.02, eta = 0.61). The present data suggest only very strong individuals (back squat > or = 2.0 x body mass) exhibit a potentiation effect in a horizontal plyometric activity after performing an ascending back squat protocol.