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

Area of Science:

• Exercise Physiology
• Biomedical Engineering
• Sports Science

Background:

• Estimating physical working capacity at fatigue threshold (PWCFT) is crucial for assessing exercise performance.
• The maximal distance-electromyography (Dmax-EMG) method offers a potential alternative for PWCFT estimation.

Purpose of the Study:

• To validate the Dmax-EMG method against the original (ORG) method for estimating PWCFT.
• To assess the sensitivity of the Dmax-EMG method to changes in PWCFT following high-intensity interval training (HIIT).

Main Methods:

• Twenty-one healthy adults underwent 12 HIIT sessions over 4 weeks.
• Physical working capacity at fatigue threshold (PWCFT) was assessed using both Dmax-EMG and ORG methods before and after the HIIT intervention.
• Graded exercise tests (GXT) were employed for PWCFT estimation.

Main Results:

• Both ORG and Dmax-EMG methods showed significant increases in PWCFT post-HIIT (+10.6% and +12.1%, respectively).
• No significant differences were found in the magnitude of PWCFT changes between the two methods.
• Bland-Altman analysis revealed non-significant biases between the ORG and Dmax-EMG methods at both pre- and post-HIIT stages.

Conclusions:

• The Dmax-EMG method is a valid and reliable tool for estimating PWCFT in young men and women.
• The Dmax-EMG method demonstrates sensitivity to training-induced adaptations in physical working capacity.