Intrinsic Motoneuron Excitability Differentiates Sarcopenic, Nonsarcopenic and Athletic Ageing Phenotypes.

Abstract

The mechanisms underlying sarcopenia-related physical decline remain poorly understood, particularly with respect to neural contributions. Muscle atrophy has traditionally been viewed as the primary driver, but growing evidence suggests that neuromuscular impairments-especially reduced intrinsic motoneuron excitability-may play a central role. This intrinsic excitability, which is critical for modulating motoneuron discharge rates, likely contributes to age-related weakness and mobility loss. We investigated whether intrinsic motoneuron excitability differs across older adults with sarcopenia, nonsarcopenic controls and masters athletes and whether these differences relate to physical function.