Article

OBJECTIVES: To determine whether maximal force is similar between conditions with
and without a microelectrode, and to evaluate potential sex differences when
using invasive procedures. DESIGN: Crossover trial. SETTING: University
laboratory. PARTICIPANTS: Young men (n=8; mean +/- SD age, 20.3+/-2.0y) and young
women (n=8; mean age +/- SD, 19.8+/-0.4y). INTERVENTIONS: Not applicable. MAIN
OUTCOME MEASURES: Subjects randomly performed 5 ankle dorsiflexion maximal
voluntary contractions (MVCs) with an indwelling microelectrode in the tibialis
anterior and 5 MVCs with the twitch interpolation technique without a
microelectrode. Strength and contractile properties were measured. No visual or
oral feedback was provided. When the greatest MVCs from each condition differed
by more than 5%, 3 additional attempts were given with feedback in the lesser of
the 2 conditions. RESULTS: Men were approximately 39% stronger than women, and
contractile properties were approximately 11% faster, but maximal voluntary
activation was similar between sexes ( approximately 95%). However, in men and
women, the greatest MVC did not differ between the microelectrode and activation
conditions (P=.87). In 9 of the 16 subjects, MVC was about 5% less in 1 of 2
conditions. Five of these 9 subjects were able to match or exceed their highest
MVC with the aid of visual feedback. CONCLUSIONS: This suggests that muscle
strength and contractile properties differ between men and women. Indwelling
microelectrodes do not hinder the ability to achieve MVC, but adequate feedback
is necessary to achieve the highest force.

Langue : ANGLAIS