Neuromuscular adaptations to low-frequency stimulation training in a patient with chronic heart failure.

Electrical myostimulation (EMS) has recently been proposed as an interesting rehabilitation tool in patients with chronic heart failure (CHF). Although its beneficial effects on exercise capacity and muscle strength have been demonstrated, the neuromuscular adaptations responsible for improved performance are not well understood. This preliminary case report was therefore planned to investigate the neural and muscular adaptations to a 5-wk EMS program in one patient. An increase in maximal strength (10.5%) was accompanied by increased twitch torque (13.9%) and slowing of muscle contractile properties (half-relaxation time, time to peak torque, and maximal rate of relaxation increased by 7.1, 31.1, and 16.6%, respectively) without changes in muscle activation. This preliminary case report therefore shows that in a highly deconditioned patient, EMS training improved strength through muscular adaptations rather than by neural changes, suggesting that EMS may be valuable for counterbalancing loss of muscle strength and function common in CHF patients.