The study aimed to determine the acute effects of subtetanic neuromuscular
electrical stimulation (NMES) combined with active recovery between sprint
exercises on blood lactate accumulation, sprint performance, and muscle fatigue.
Sixteen healthy young individuals [23(4) years, 10 males] underwent a 1-min rest
followed by sprint interval training consisting of four 15-sec maximal sprint
exercises with three 5-min active cycling sessions. Participants engaged in
voluntary cycling at 40% of peak oxygen consumption, with or without NMES (VOLES
or VOL; interventions). Blood lactate concentration ([La]b) was
assessed at the end of the rest and each intervention periods. Mean power was
assessed during each sprint exercise session. Maximum voluntary contraction
(MVC) of the knee extensor was measured before and after sprint interval
training to evaluate muscle fatigue. The [La]b was significantly
higher in VOLES than in VOL (main effect, P=0.037). Mean power did not differ
between conditions (main effect and interaction, P>0.050). MVC after sprint
interval exercise was significantly lower in VOLES than in VOL (interaction,
P<0.001). Subtetanic NMES combined with voluntary cycling enhanced blood
lactate accumulation and induced greater voluntary fatigue but resulted in
similar peripheral muscle fatigue and sprint exercise performance compared with
voluntary cycling without NMES.