Acute effects of fast eccentric contractions with different load on the postactivation potentiation

Background: This study aimed to investigate the acute effects of fast eccentric contractions with different load on the postactivation potentiation (PAP). Methods: Potentiation was performed using 3 sets of 3 repetitions with dynamic contractions (EC90%) at 90% of one repetition maximum (1RM), fast eccentric contractions at 60% (ECC60%), and 40% (ECC40%) 1RM on a sample of 21 students. The procedure was carried out in four sessions with a 7-day rest between sessions. Anthropometric measurements and 1RM assessment using the barbell squat on the Smith machine were conducted in the first session. Acute PAP effects were assessed based on kinematic parameters (h - maximal jump height) using pretest and posttest Countermovement Jump (CMJ) tests in the second, third, and fourth sessions. The rest period between the potentiation stimulus and CMJ was 6 minutes for all conditions. Results: Repeated measures ANOVA showed significant differences in jump height after all three types of potentiation (p < .001). Bonferroni post-hoc analysis revealed significant differences between EC90% (2.91 ± 1.1 cm) and ECC60% (2.56 ± 0.9 cm) potentiation (p < .005). Additionally, jump height after EC90% and ECC60% was significantly higher compared to ECC40% (1.01 ± 0.3 cm). Conclusions: The results suggest that dynamic loads of 90% 1RM, along with 60% and 40% via fast eccentric contractions, can be used for acute increases in CMJ height after 6 minutes of rest. Furthermore, potentiation with fast eccentric contractions and moderate load shows similar effects on CMJ height as dynamic submaximal loads, a valuable finding for strength and conditioning coaches.