Effect Of Accentuated Eccentric Loading Tempo On Post Activation Performance Enhancement During A Back Squat

PURPOSE: Accentuated eccentric loading (AEL) has gained popularity due to its potential to enhance eccentric force production compared to traditional resistance training. However, most research has used loads ranging between 120-80% 1-repetition maximum (1RM). To our knowledge, no research has investigated the effect of AEL while using a light load (40% 1RM) during the concentric portion of the movement. Therefore, the purpose of this study is to examine the effect of tempo during an AEL back squat with a light concentric load on lower body power output. METHODS: Nine male participants in a randomized cross-over design study separated by seven days. The participants completed a 5x3 back squat protocol with 100% 1RM on the eccentric portion and 40% 1RM during the concentric portion of the movement with a 1 second eccentric (FT) or 3 second eccentric tempo (ST). After each set, the participant passively rested for three minutes and then performed two countermovement jumps arms akimbo. Jumps were performed on force plates and were analyzed using a customized Excel spreadsheet to extract jump height (JH), peak power output (PPO), concentric and eccentric impulse, reactive strength index-modified (RSImod), and time to takeoff. Repeated-measures ANOVA were performed to determine differences between tempo and across sets. Cohen’s d effect sizes were calculated to determine magnitude of differences. Alpha level was set a p < 0.05. RESULTS: Results indicated that JH (0.43 ± 0.07 m vs. 0.41 ± 0.07 m) and PPO (4875 ± 763 W vs. 4577 ± 744 W) decreased during the FT condition (p < 0.05) but did not during the ST condition. CONCLUSIONS: It appears that FT leads to a decrement in lower body power output via a decrease in eccentric impulse. This may be from limited tension that is generated by the muscle during the FT. Practitioners should investigate different tempos to see if lower body power is enhanced to a greater extent when doing a light concentric load during AEL protocols.