The 3-min all-out test in cycling: a systematic review and meta-analysis on its reliability and validity

The 3-min all-out test is considered a time-efficient alternative for estimating critical power (CP) and curvature constant (W'), by means of endtest power (EP) and work done above endtest power (WEP), respectively. This review aims to assess its reliability and validity with respect to methodology. Following the PRISMA 2020 guidelines, a systematic literature search was conducted on June 20th 2025, using a specified search term in PubMed and Web of Science. Included studies were English-language, peer-reviewed original articles, that provided empirical data on the 3-min all-out test in cycling and used appropriate protocols for assessing reliability/validity. Quality of studies was assessed using a modified critical appraisal tool. Meta-analysis for validity was done using pooled Hedge's g_z with random effects synthesis and 95%prediction intervals. Twenty studies comprising N = 284 participants met all inclusion criteria. Thereof, 15 studies examined validity, 8 reliability and 3 both. Included studies demonstrated methodological heterogeneity and small sample sizes (n = 6-21). Test-retest reliability demonstrated 'good' to 'excellent' agreement for EP (ICC = 0.89-0.99) and WEP (ICC = 0.76-0.98). EP systematically overestimates CP (g_z= 0.408 [0.024, 0.792]) while WEP underestimates W' (g_z= -0.389 [-0.954, 0.176]). Whereas the 3-min all-out test provides reliable results for EP and WEP if tests are conducted within three weeks, its validity seems to largely depend on the methodological approach. Certain power profiles and/or isokinetic 3-min tests lead to better estimates of CP, while the variability of WEP does not allow to accurately estimate W'. Familiarisation trials and proper verbal encouragement during the 3-min test are mandatory.