The Dmax method is a valid procedure to estimate physical working capacity at fatigue threshold.
Riffe JJ, Stout JR, Fukuda DH, Robinson EH, Miramonti AA, Beyer KS, Wang R, Church DD, Muddle TW, Hoffman JR. The Dmax method is a valid procedure to estimate physical working capacity at fatigue threshold. Muscle Nerve. 2017 03; 55(3):344-349.