The Effects of Gender on Fatigue-Induced Changes in Electromechanical Efficiency and Torque

Electromechanical efficiency (efficiencyE-M) has been used to detect changes in neuromuscular function and track decreases in torque production as a result of muscle fatigue. No previous investigations, however, have applied efficiencyEM to examine gender-specific decreases in torque as a result of fatigue. Therefore, the purpose of the present investigation was to examine gender differences in the fatigue-related effects on efficiencyE-M (mechanomyographic amplitude ÷ electromyographic amplitude) during repeated, submaximal, concentric forearm flexion muscle actions. Eleven men and eleven women performed 50 consecutive submaximal (65% of concentric peak torque), concentric muscle actions of the forearm flexors at 60°·s. There were decreases in pretest versus posttest concentric peak torque for both the men (30.5%) and women (22.3%) as a result of the fatiguing exercise bout, but the decrease was greater for the men. During the fatiguing exercise bout, torque output remained unchanged at 65% of concentric peak torque, while efficiencyEM decreased for both the men and women. Thus, efficiencyE-M did not track torque production during the submaximal fatiguing protocol.