EFFECT OF ADDITIONAL ELECTRICAL STIMULATION OF MUSCLES ON MAXIMAL FORCE PRODUCTION

The effect of additional electrical stimulation (ES) of quadriceps femuris muscle on muscle force production was investigated during maximal voluntary isometric contraction (MVC). Eight sport students, all in good condition, participated in the study. ES consisted from the trains of impulses of different length (single impulse, 0.05 s, 0.10 s, 0.15 s, and 0.20 s) with the frequency of 100 Hz. After reaching the maximal voluntary force level, the ES was applied directly to the muscle. Results show the growing muscle force over the MVC level in all stimulating conditions reaching its plateau at 0.10 s of ES (24 % over the MVC). This suggests that the certain minimum time of the additional activation is needed to elicit the whole muscle force capacity. Results may help to elucidate the possible mechanical effects of the reflex activation of the muscles