Validity and reliability of the 3-min all-out running test to measure critical velocity in hot environments

This study’s aim was to investigate the test–retest reliability of the 3-min all-out running test (3MRT) in hot environments. Twelve male sprinters (age 21.2 ± 1.8 years; height 1.78 ± 0.01 m; weight 71.0 ± 1.6 kg; VO_2max 55.0 ± 1.0 mL kg⁻¹ min⁻¹) performed an incremental exercise test in a laboratory, during which the first and second ventilatory thresholds (VT₁ and VT₂) and VO_2max were determined. In addition, they performed two 3MRTs on an outdoor track in a hot environment, during which the critical velocity (CV) and anaerobic capacity (D′) were estimated. Significant reproducibility was found in CV and D′ (ICC = 0.74 and 0.61, P < 0.05). The average CV in 3MRTs (3.09 ± 0.13 m s⁻¹) correlated significantly with VT₁ (3.13 ± 0.07 m s⁻¹, P < 0.05). The 3MRT is a reliable tool for measuring CV and D′, while CV from 3MRT in a hot environment was identical to VT₁.