Test-retest reliability and circadian performance variability of a 15-s Wingate Anaerobic Test

The purpose of this study was to examine the test-retest reliability and circadian variability of an abbreviated, 15-s version of the Wingate Anaerobic Test (WAnT₁₅). A total of 35 healthy, physically-active subjects (20.2 + 3.6 years) performed two WAnT₁₅ tests, 24 h apart (Reliability phase; n = 18), and on a different occasion performed morning and evening WAnT₁₅ tests, (Circadian phase; n = 17). In the reliability phase, tests 1-2 differences and intra class correlations for peak power output (PPO) and mean power output (MPO) were 0.22% and 0.997 and 0.38% and 0.996, respectively. The fatigue index (FI) was not found reliable. In the circadian phase, only PPO significantly changed between morning and evening sessions (3.0%, p = 0.021). These findings suggest that the shortened WAnT₁₅ is a highly reliable anaerobic power test with circadian variability 550% that reported for the original, 30-s WAnT, in previous studies.