Abstract
The primary purpose of the present investigation was to examine sex-related differences
as a result of fatiguing eccentric muscle actions on torque, muscle blood flow, electromyography,
and mechanomyography. Eighteen men and 18 women performed peak torque trials prior
to (pretest), immediately after (posttest), and 5-min after (recovery) completing
50 submaximal (60% of eccentric peak torque), eccentric, isokinetic (180°·s
−1) muscle actions of the elbow flexors. Electromyographic and mechanomyographic responses
were simultaneously recorded from the biceps brachii muscle, and muscle blood flow
was measured at pretest, posttest and recovery. There were sex- and mode-specific
responses for torque, but there were no sex-specific muscle blood flow or neuromuscular
responses. From pretest to posttest, torque decreased (80.0–88.2% of pretest) for
both the men and women. At recovery concentric peak torque recovered to a greater
extent in women (95.0% of pretest) than men (88.0% of pretest), while eccentric peak
torque recovered to a greater extent in men (88.9% of pretest) than women (86.9% of
pretest). The sex-specific torque responses were not associated with different motor
control strategies or differences in the occlusion of muscle blood flow between the
men and women. For both men and women, eccentric fatiguing exercise is manifested
similarly during isometric muscle actions, but not during eccentric and concentric
muscle actions.
Key words
blood flow - motor control - isokinetic - muscle fatigue - gender - EMG - MMG
