Compound Muscle Action Potential Parameters of the Extensor Digitorum Brevis in Sprinters and Sedentary Individuals:...

Background: Compound muscle action potential (CMAP) parameters provide objective information on peripheral neuromuscular function, yet comparisons between track athletes and sedentary individuals remain limited, particularly when stratified by sex. This exploratory study examined whether CMAP parameters differ between sprinters and sedentary controls, with a secondary descriptive analysis of female middle-distance runners. Methods: A total of 48 participants (27 females, 21 males) aged 15 to 28 years were recruited by convenience from a restricted-access athletic population. The main comparisons focused on sprinters versus sex-matched sedentary controls, analyzed separately in females (9 sprinters, 10 controls) and males (10 sprinters, 11 controls). Female middle-distance runners (n = 8) were retained as an exploratory subgroup. Bilateral peroneal nerve conduction studies were performed in the extensor digitorum brevis. Outcomes included latency, amplitude, nerve conduction velocity, and CMAP duration. Main comparisons used Welch's t-tests, supplemented by Mann-Whitney U tests. Effect sizes (Hedges' g) and 95% confidence intervals were reported. A BMI-adjusted model examined whether the main female finding remained after accounting for BMI. Results: Female sprinters showed significantly higher right-sided CMAP amplitude than sedentary females (Welch p = 0.017; Hedges' g = 1.32; 95% CI of the mean difference, 0.68 to 5.44 mV), supported by non-parametric testing (p = 0.025). The group effect remained significant after BMI adjustment. No other comparisons reached statistical significance. In males, no significant differences were observed. Conclusions: The main finding was a higher right-sided CMAP amplitude in female sprinters compared with sedentary controls, reasonably consistent across complementary parametric, non-parametric, and BMI-adjusted analyses. Given the small sample and exploratory design, these findings warrant cautious interpretation and replication in larger studies.