Poster can be found in location 149.

INTRODUCTION: Sarcopenia is an age-related pathological condition characterized by loss of skeletal muscle mass and function and has a serious adverse impact on health for elderly. Recent clinical perspectives have emphasized the significance of muscle function for sarcopenia. Given that motor unit is the fundamental function unit of neuromuscular system, comprehensively understanding its firing characteristics would allow to further elucidate pathological mechanism underlying sarcopenia from the perspective of muscle function.

OBJECTS: Accordingly, the study aimed at clarifying firing characteristics of neuromuscular motor unit among sarcopenia populations and asymptomatic controls.

METHODS: A total of 30 sarcopenic participants (20 females; 67.2 (±7.1) years old) and 30 non-sarcopenic individuals (17 females; 65.1 (±9.8) years old) performed the Five Times Sit-to-Stand Test to acquire motor unit firing characteristics of vastus lateralis muscle. For each detected motor unit, its average firing rate and average motor unit action potential train amplitude were considered for analysis. Subsequently, the scale factor (an estimate of the average firing rate of the smaller motor unit) and decay constant (firing rate of decay as a function of motor unit action potential train amplitude) for each subject were determined by means of the exponential decay functions.

RESULTS: The preliminary results displayed higher scale factor (P = 0.001) and lower decay constant (P < 0.001) for detected motor units of the vastus lateralis muscle among sarcopenic participants, signifying that sarcopenic individuals would alter neuromuscular control strategies.

CONSUCLUSIONS: Considering the clinical relevance of muscle function, the motor unit firing characteristics may be used an early screening methodology for precise identifying sarcopenia