Associations of Serum MOTS-c with Exercise Capacity and Antioxidant Markers in Young Males: A Cross-Sectional Study

Mitochondrial-derived peptide MOTS-c is an exercise-responsive mitokine, yet its associations with exercise capacity and antioxidant markers remain unclear. This cross-sectional study examined serum MOTS-c across three stratified groups of 30 healthy young males aged 18 to 25 years: elite track and field athletes (n = 10), recreationally active individuals (n = 10), and sedentary controls (n = 10). Measurements included serum MOTS-c, SOD, post-exercise MDA, VO2max, forced vital capacity, vertical jump height, handgrip strength, back muscle endurance, and post-fatigue back muscle force. Serum MOTS-c increased progressively across groups (athletes: 507.51 ± 67.42 pg/mL; active: 440.32 ± 32.83 pg/mL; sedentary: 319.31 ± 99.07 pg/mL; p < 0.001; Hedges’ g = 2.13 for athlete vs. sedentary comparison). Serum MOTS-c was strongly correlated with absolute VO2max (r = 0.892), SOD (r = 0.847), post-exercise MDA (r = −0.910), back muscle endurance (r = 0.725), and post-fatigue back muscle force (r = 0.812) (all p < 0.001). In exploratory hierarchical regression, post-exercise MDA remained significantly associated with serum MOTS-c after adjustment for VO2max, whereas SOD was not independently associated. Handgrip strength showed no significant correlation with MOTS-c (r = 0.315, p = 0.090). These findings suggest that serum MOTS-c is associated with exercise capacity and circulating antioxidant markers in young males, although the cross-sectional design precludes causal inference.