Abstract Yang, Y-R, Wang, H-J, Lin, C-Y, Lin, Y-D, and Cheng, C-F. Reliability and validity of critical force estimated from a 3-minute all-out squat test. J Strength Cond Res XX(X): 000–000, 2026—This study aimed to develop a 3-minute all-out squat test (3MST) to determine critical force (CF) in the squat exercise and to evaluate its reliability and validity. Fifteen trained men participated in the study and completed a maximal strength test, 3 repetitions-to-exhaustion tests to estimate CF and F′ , and 2 3MSTs to assess end-test force (EF) and work above EF (WEF). Heart rate (HR) and changes in deoxyhemoglobin concentration (ΔHHb) were recorded during the 3MSTs. Blood lactate concentration (La) was collected 5 minutes after the 3MSTs. Both EF (intraclass correlation coefficient ICC = 0.975–0.980, p 0.05). However, WEF was significantly greater than F′ estimated from the 3 models ( p 0.05), as did La. These results indicated that the 3MST is a valid and reliable tool for estimating CF in squat exercise and may be used to identify anchor intensity before prescribing a resistance training program.
Yang et al. (Fri,) studied this question.