The Effects of Post-Activation Performance Enhancement on High Intensity Interval Training: A Comparison of...

The present study aimed to examine the effects of post-activation performance enhancement (PAPE) protocols employing half-squat exercises, performed using either a traditional set (PAPE_{traditionalset}) or a cluster set (PAPE_clusterset), on peak oxygen uptake ( $\dot{V}$ O_2peak), the time spent at ≥ 90% maximal oxygen uptake ( $\dot{V}$ O_2max), and total exercise duration during high-intensity interval training (HIIT) in trained athletes. Ten well-trained endurance athletes involved in endurance sport ( $\dot{V}$ O_2max: 63.3 ± 5.1 mL·kg^-1∙min^-1) completed three HIIT sessions (until failure x (1-min run at $\dot{V}$ O_2max velocity + 1-min active recovery at 30% $\dot{V}$ O_2max velocity)) under different conditions: (i) control (warm-up only: jogging and stretching), (ii) warm-up + three sets of six repetitions of the half-squat (traditional set; 120 s of rest between sets), and (iii) warm-up + three sets of 2 + 2 + 2 repetitions of half-squat (cluster set; 20-s rest after each two-repetition cluster and 80-s rest between sets). No significant differences were found in $\dot{V}$ O_2peak responses among the three HIIT protocols (control: 62.3 ± 5.1 mL·kg^-1·min^-1; PAPE_{traditionalset}: 61.6 ± 4.0 mL·kg^-1·min^-1; PAPE_clusterset: 61.9 ± 3.7 mL·kg^-1·min^-1; p = 0.198). However, both PAPE protocols increased time at ≥ 90% $\dot{V}$ O_2max (control: 6.21 ± 0.9 min; PAPE_{traditionalset}: 7.43 ± 1.2 min; PAPE_clusterset: 8.11 ± 1.4 min; p < 0.001) and total work duration (control: 12.0 ± 0.96 min; PAPE_{traditionalset}: 13.4 ± 1.54 min; PAPE_clusterset: 14.4 ± 1.53 min; p < 0.001) compared with control. Additionally, the PAPE_clusterset resulted in a significantly longer time spent at ≥ 90% $\dot{V}$ O_2max (p = 0.005) and total work duration compared with the PAPE_{traditionalset} (p = 0.043). PAPE protocols, especially using cluster sets, increase time ≥ 90% $\dot{V}$ O_2max and total work duration during HIIT, potentially enhancing endurance performance.