MOTS-c Levels Linked to Lower-Body Strength, Not Aerobic Fitness
Background
The mitochondrial-derived peptide MOTS-c is a fascinating molecule known for its roles in metabolic regulation, insulin sensitivity, and cellular stress response. While its systemic effects are increasingly recognized, the specific relationship between circulating MOTS-c levels and different aspects of physical fitness, such as muscle strength versus aerobic capacity, remains less understood. This study aimed to clarify how MOTS-c serum concentrations correlate with lower-body muscle strength and maximal oxygen uptake in healthy individuals.
Results
The study revealed a significant positive correlation between MOTS-c serum concentrations and several measures of lower-body muscle strength. Specifically, MOTS-c levels showed a positive correlation with peak torque (a measure of rotational force) of knee extensors at 60°/s (r=0.34, p=0.017) and 180°/s (r=0.32, p=0.027). Similar positive correlations were observed for knee flexors at 60°/s (r=0.33, p=0.022) and 180°/s (r=0.30, p=0.038). The strongest correlation was observed between MOTS-c levels and knee extensor peak torque at 60°/s, suggesting a direct link between this peptide and muscle power. In contrast, no significant correlation was found between MOTS-c serum concentrations and maximal oxygen uptake (VO2max), with a correlation coefficient of r=0.09 (p=0.53), indicating MOTS-c's influence might be more specific to muscle strength rather than aerobic capacity.
Why It Matters
These findings are significant because they identify MOTS-c as a potential biomarker for lower-body muscle strength, independent of aerobic fitness. This specificity could make MOTS-c a valuable tool for assessing muscle health and performance, potentially offering insights beyond traditional fitness markers. Further research could explore MOTS-c as a therapeutic target or intervention to combat age-related muscle decline (sarcopenia), enhance athletic performance, or aid in rehabilitation programs. Future studies, including longitudinal and interventional human trials (e.g., Phase II), are warranted to confirm these correlational findings and investigate the causal mechanisms and clinical utility of MOTS-c.