The Dmax method is a valid procedure to estimate physical working capacity at fatigue threshold

Introduction: The purpose of this study was to determine the validity of the maximal distance–electromyography (Dmax-EMG) method for estimating physical working capacity at fatigue threshold (PWC_FT). Methods: Twenty-one men and women (age 22.9 ± 3.0 years) volunteered to perform 12 sessions of high-intensity interval training (HIIT) over 4 weeks. Before and after HIIT training, a graded exercise test (GXT) was used to estimate PWC_FT using the Dmax method and the original (ORG) method. Results: There was a significant increase in PWC_FT for both ORG (+10.6%) and Dmax (+12.1%) methods, but no significant difference in the change values between methods. Further, Bland–Altman analyses resulted in non-significant biases (ORG–Dmax) between methods at pre-HIIT (–6.4 ± 32.5 W; P > 0.05) and post-HIIT (–4.2 ± 33.1 W; P > 0.05). Conclusion: The Dmax method is sensitive to training and is a valid method for estimating PWC_FT in young men and women. Muscle Nerve 55: 344–349, 2017.