Key Takeaway
SIT produces a medium overall effect on physical performance (ES = 0.52), with the largest improvements in anaerobic outcomes (ES = 0.61), though small-study effects suggest some overestimation.
Summary
This systematic review and meta-analysis examined the effects of sprint interval training (SIT) on a broad range of physical performance outcomes. Drawing from 55 studies, the authors pooled data across aerobic, anaerobic, and body composition measures to quantify SIT's overall impact and identify which domains benefit most.
The analysis found a medium positive effect of SIT on physical performance overall (ES = 0.52), with anaerobic outcomes showing the largest effect sizes (ES = 0.61). Aerobic fitness measures such as VO2max also improved significantly but to a slightly lesser degree. The review confirmed SIT as a time-efficient training modality capable of producing meaningful adaptations across multiple fitness domains.
However, the authors flagged small-study effects in the literature, meaning that smaller studies tended to report larger effect sizes. This suggests some degree of publication bias and potential overestimation of SIT's true effect. The findings support SIT as an effective training strategy but highlight the need for larger, higher-quality trials.
Methods
Systematic review and meta-analysis of 55 studies examining SIT protocols (typically 20-30 second all-out sprints with recovery periods). Random-effects models were used to pool effect sizes across studies. Outcomes were categorized into aerobic performance, anaerobic performance, and body composition. Subgroup analyses and funnel plot asymmetry assessments were conducted to evaluate potential moderators and publication bias.
Key Results
- Overall pooled effect size for physical performance: ES = 0.52 (medium)
- Anaerobic outcomes showed the largest effect: ES = 0.61
- Aerobic outcomes (VO2max, endurance) also improved significantly
- Small-study effects detected, indicating potential publication bias and overestimation of effects in smaller trials
- SIT effective across different populations and protocol variations
Limitations
- Small-study effects suggest publication bias may inflate reported benefits
- Heterogeneity in SIT protocols (sprint duration, recovery, frequency) across studies
- Many included studies had small sample sizes
- Limited long-term follow-up data beyond typical 4-12 week interventions
- Variability in control group conditions (no exercise vs. moderate exercise)