Superimposed electrical stimulation comfortably improves the endurance of maximal voluntary contractions

Abstract

Aim: Electrical stimulation has shown to improve muscle endurance in sub-maximal contractions but sessions were painful due to the electric stimuli parameters. Therefore, the present study tested the effects of the superimposed electrical stimulation technique using comfortable current on endurance in repetitions of maximal voluntary contraction.

Methods: Seventeen young healthy subjects performed fifty maximal voluntary contractions of the triceps brachii in two conditions of contraction (voluntary vs. voluntary + superimposed electrical stimulation).

Results: Peak force and force-time integral were consistently decreased in the voluntary muscular contraction condition after the 20th - 30th trials whereas they were maintained in the superimposed electrical stimulation condition (P<0.05) until the end of the fifty trials.

Conclusion: The superimposition of neuromuscular electrical stimulation extends the muscle ability to repeat maximal voluntary contractions. The present results also evidenced the ability of the superimposed electrical stimulation technique to make the mechanisms of muscle central fatigue inefficient.