# Effects of Two Nights of Severe vs. Mild Sleep Restriction on Vertical Jump Performance in Physically Active Female Students

## TL;DR

This study found that two nights of severe sleep restriction may reduce vertical jump performance in physically active female students.

## Contribution

The study explores the effects of severe versus mild sleep restriction on vertical jump performance in female students.

## Key findings

- Severe sleep restriction significantly decreased SJ performance with a large effect size.
- CMJ performance showed a non-significant decrease with a moderate effect size.
- Between-group comparisons showed no significant differences in jump performance.

## Abstract

Partial sleep deprivation is common in sports, particularly before competitions. This study examined whether two nights of severe sleep restriction (<4 h/night), compared with mild sleep restriction (control), are associated with changes in SJ and CMJ in physically active female students. Twenty-three female students (n = 12 experimental; n = 11 control) were randomly assigned to their respective groups. The experimental group underwent two nights of severe sleep restriction (<4 h/night), while the control group experienced mild sleep restriction. Differences between groups were analyzed using Quade’s nonparametric ANCOVA (sleep duration as covariate), and within-group pre–post changes were evaluated using paired-samples t-tests. No significant differences were found between groups after two nights in CMJ (p = 0.92) or SJ (p = 0.73) performance. Within the experimental group, SJ performance significantly decreased from the initial to the final assessment (p = 0.02), with a large effect size (d = −0.81). CMJ performance in the experimental group showed a non-significant decrease with a moderate effect size (d = −0.45). No significant differences or notable effect sizes were found in the control group (d = 0.01 to 0.23). Within-group results suggest that SJ decreased after severe sleep restriction, while CMJ changes were smaller and not statistically significant; between-group comparisons were not significant, and results appear sensitive to the analytical approach. These exploratory findings suggest that monitoring sleep before power-related tasks may be warranted. Coaches may consider monitoring sleep duration before high-intensity power training, as two nights of severe sleep restriction may be associated with reduced SJ performance.