Effects of high-intensity interval training on aerobic capacity and athletic performance in trained athletes: a systematic review and meta-analysis

This study conducted a systematic review with meta-analysis to investigate the effects of high-intensity interval training (HIIT) on aerobic capacity and performance in trained athletes. The data sources utilized were PubMed, EBSCO, and Web of Science. Eligibility included trained athletes, encompassing amateur, elite, or professional male and female participants, with no age restrictions. Outcome measures include aerobic capacity and performance. Methodological quality was assessed using the Cochrane, Bias risk assessment tool. The search identified 4,289 titles, with 18 articles eligible for the review and meta-analysis. The results showed that HIIT significantly improved VO2max (SMD: 1.11, 95% CI: 0.48, 1.74; heterogeneity p < 0.1) and VO2peak (MD: 0.52, 95% CI: 0.08, 0.97; heterogeneity p < 0.1) in trained athletes, indicating a remarkable effect of HIIT in enhancing aerobic capacity. In terms of athletic performance, HIIT significantly improved speed (MD: -0.72, 95% CI: -1.41, -0.03; heterogeneity p < 0.1) and agility (MD: -0.93, 95% CI: -1.79, -0.06; heterogeneity p < 0.1). However, no significant effects of HIIT were observed on HRmax, jump, and power, suggesting that its main advantages are focused on cardiopulmonary endurance and efficiency-related indicators rather than maximal strength or explosive power.