Force; Power; Jump
Post activation potentiation (PAP) is a phenomenon where performance in power or speed movements increases after a performing high force conditioning exercise. The most common PAP observation is an increase in jump height after performing a weighted squat. In contrast, few studies have observed PAP in the upper body and it is unknown if upper and lower body muscles experience a similar PAP response. This has potential applications for athletes who use their upper body such as shot putters or boxers. In this study, we examined the effects of PAP in the lower extremity by seeing if a weighted squat can improve vertical jump (VJ) performance and in the upper extremities by seeing if a bench press can improve bench press throw (BT) performance. To test the research question, 9 strength trained (maximum squat > 1.5 time body weight and maximum bench press > 1.25 times body weight) participants took part in upper and lower body PAP testing in which they performed a power exercise (VJ or BT), a heavy conditioning exercise (weighted squat or bench press) and then repeated the power exercise. VJ and BT were performed on a force plate with ground reaction forces measured at 200 Hz and performance was assessed by calculating peak power output, peak velocity, and peak force from force plate data. The conditioning activities were 1 set of 3 reps at 85% of maximum load on both the bench press and squat lift respectively. A paired t-test was used to compare pre and post conditioning exercise performance in the VJ and BT. Results indicated a PAP in the BT as peak force significantly increased after the conditioning exercise (Δ63.2 ± 48.7 N; p = 0.003). However, BT peak velocity (Δ-0.14 ± 0.33 m/s; p = 0.228) and BT peak power (Δ147 ± 288 W; p = 0.141) did not significantly change. No PAP response was seen in the VJ where peak force non-significantly decreased after the conditioning exercise (Δ-49 ± 202 N; p = 0.438) and peak velocity (Δ0.12 ± 0.27 m/s; p = 0.179) and peak power (Δ 261 ± 456 W; p = 0.141) non-significantly increased after the conditioning exercise. Contrary to previous works we did not observe a VJ-PAP response and in fact saw a non-significant decrease in performance in some variables. In contrast, we did observe a significant PAP response in the BT. PAP responses seem to differ on a case-by-case basis, possibly depending on muscle fiber distribution and history of training. Determining so called “responders” and “non-responders” within athletes will determine whether PAP could be used practically in upper and lower body movements.