Is the Ability to Maximally Activate the Dorsiflexors in Men and Women Affected by Indwelling Electromyography Needles?

Brown RE, Bruce SH, Jakobi JM. Is the ability to maximally activate the dorsiflexors in men and women affected by indwelling electromyography needles?ObjectivesTo determine whether maximal force is similar between conditions with and without a microelectrode, and to evaluate potential sex differences when using invasive procedures.DesignCrossover trial.SettingUniversity laboratory.ParticipantsYoung men (n=8; mean ± SD age, 20.3±2.0y) and young women (n=8; mean age ± SD, 19.8±0.4y).InterventionsNot applicable.Main Outcome MeasuresSubjects 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.ResultsMen were ∼39% stronger than women, and contractile properties were ∼11% faster, but maximal voluntary activation was similar between sexes (∼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.ConclusionsThis 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.