C-terminal agrin fragment is inversely related to neuromuscular fatigue in older men.

INTRODUCTION The aim of this study was to examine the relationship between serum C-terminal agrin fragment (CAF) concentrations and neuromuscular fatigue in older adults. METHODS Twenty-two healthy older men and women volunteered for this study. Resting fasted blood samples were collected and prepared for measurement of serum CAF concentration by a commercially available ELISA kit. The onset of neuromuscular fatigue was measured by monitoring electromyographic fatigue curves from the vastus lateralis muscle using the physical working capacity at fatigue threshold (PWCFT ) test. RESULTS A significant inverse correlation for men was observed between CAF and PWCFT (r = -0.602; P = 0.05), but not for women (r = 0.208; P = 0.54). After controlling for age and body mass index, significant correlations (r = -0.69; P = 0.042) remained for men, but not for women (r = 0.12; P = 0.76). CONCLUSIONS These data suggest that serum CAF concentrations were significantly related to the onset of neuromuscular fatigue independent of age and BMI in men only.