# Comparison of post-activation performance enhancement in the lower limbs of short sprinters based on two velocity loss thresholds

## TL;DR

This study compares how two different velocity loss thresholds affect explosive lower-limb performance in sprinters after resistance training.

## Contribution

The study identifies optimal velocity loss thresholds and recovery times for maximizing post-activation performance enhancement in sprinters.

## Key findings

- A 5% velocity loss improved jump height, power, and sprint performance at 8 minutes with fewer repetitions.
- A 15% velocity loss improved sprint performance at 8 minutes but did not enhance jump performance.
- The 5% condition required fewer squat repetitions to achieve performance improvements.

## Abstract

The present study examined the effects of post-activation performance enhancement (PAPE) induced by different velocity loss (VL) thresholds on lower-limb explosive performance in sprinters under velocity-based resistance training (VBT). A secondary aim was to identify the optimal VL thresholds (5% and 15%) and recovery time points (PRE, 4, 8, 12, and 16 min) for maximizing PAPE responses.

Using a randomized crossover design, fifteen male sprinters completed two PAPE protocols consisting of deep squats performed at 85% 1RM with two VL thresholds (5% and 15%). Countermovement jump (CMJ) performance (jump height, relative power, and vertical impulse) and 30 m sprint performance (total time used and average speed) were assessed at each time point. The total number of squat repetitions completed under each VL condition was also recorded.

In the 5% VL condition, significant improvements were observed in CMJ jump height (P = 0.01), relative power (P = 0.009), vertical impulse (P = 0.016) at 8 min post-intervention. In addition, both total sprint time and mean speed showed significant changes at 4 min (P = 0.014; P = 0.030) and 8 min (P = 0.011; P = 0.006). In contrast, no significant changes in CMJ variables were found at any time point in the 15% VL condition. However, total sprint time and mean speed were significantly improved at 8 min post-intervention (P = 0.002; P = 0.004). The total number of squat repetitions was significantly lower in the 5% VL condition compared with the 15% VL condition (P = 0.003 vs. P = 0.042).

Under two sets of deep squats at 85% 1RM, 5% VL was associated with CMJ improvement at 8 min and 30 m sprint improvement at 4 and 8 min with fewer repetitions, whereas 15% VL improved sprint performance mainly at 8 min with no clear CMJ enhancement.