The Effects of Post-Activation Performance Enhancement on High Intensity Interval Training: A Comparison of Traditional and Cluster Set Protocols.

No significant differences in peak oxygen uptake (VO2peak) were found among the three HIIT conditions.

• Control VO2peak: 62.3 ± 5.1 mL·kg-1·min-1; PAPEtraditionalset: 61.6 ± 4.0 mL·kg-1·min-1; PAPEclusterset: 61.9 ± 3.7 mL·kg-1·min-1
• p = 0.198 across all three conditions
• Ten well-trained endurance athletes with VO2max of 63.3 ± 5.1 mL·kg-1·min-1 participated
• All three conditions used the same HIIT protocol (until failure: 1-min run at VO2max velocity + 1-min active recovery at 30% VO2max velocity)

Both PAPE protocols significantly increased time spent at ≥ 90% VO2max compared to control.

• Control: 6.21 ± 0.9 min; PAPEtraditionalset: 7.43 ± 1.2 min; PAPEclusterset: 8.11 ± 1.4 min
• Overall difference among conditions: p < 0.001
• PAPEclusterset resulted in significantly longer time at ≥ 90% VO2max compared to PAPEtraditionalset: p = 0.005
• The traditional set protocol used three sets of six repetitions of half-squat with 120 s rest between sets

Both PAPE protocols significantly increased total exercise (work) duration compared to control.

• Control: 12.0 ± 0.96 min; PAPEtraditionalset: 13.4 ± 1.54 min; PAPEclusterset: 14.4 ± 1.53 min
• Overall difference among conditions: p < 0.001
• PAPEclusterset resulted in significantly longer total work duration compared to PAPEtraditionalset: p = 0.043
• The cluster set protocol used three sets of 2+2+2 repetitions of half-squat with 20-s rest after each two-repetition cluster and 80-s rest between sets

The PAPE cluster set protocol produced superior outcomes compared to the PAPE traditional set protocol for both time at ≥ 90% VO2max and total work duration.

• Time at ≥ 90% VO2max was longer in PAPEclusterset (8.11 ± 1.4 min) versus PAPEtraditionalset (7.43 ± 1.2 min), p = 0.005
• Total work duration was longer in PAPEclusterset (14.4 ± 1.53 min) versus PAPEtraditionalset (13.4 ± 1.54 min), p = 0.043
• Both protocols employed half-squat exercises as the conditioning activity prior to HIIT
• The cluster set protocol distributed intra-set rest (20 s after each 2-repetition cluster) within the same total set volume as the traditional set

The study used a crossover design in which ten well-trained endurance athletes completed three separate HIIT sessions under different pre-conditioning conditions.

• Participants had a mean VO2max of 63.3 ± 5.1 mL·kg-1·min-1, classifying them as well-trained endurance athletes
• The three conditions were: (i) control (warm-up only: jogging and stretching), (ii) warm-up + traditional set half-squat PAPE, and (iii) warm-up + cluster set half-squat PAPE
• HIIT was performed until failure using 1-min intervals at VO2max velocity alternated with 1-min active recovery at 30% VO2max velocity
• Sample size was n = 10