Article

OBJECTIVE: To investigate sex-related differences in the loss and recovery of
voluntary muscle strength after immobilization. DESIGN: Longitudinal, repeated
measures. SETTING: Research laboratory. PARTICIPANTS: Healthy men (n=5) and
healthy women (n=5). INTERVENTION: Three weeks of forearm immobilization. MAIN
OUTCOME MEASURES: Voluntary wrist flexion muscle strength was assessed at
baseline and weekly during the immobilization protocol and 1 week after cast
removal. Central activation was assessed before and after immobilization and
after 1 week of recovery to determine what percentage of the muscle could be
activated voluntarily. RESULTS: Men and women lost voluntary strength at a
similar rate during immobilization. However, after 1 week of recovery voluntary
strength had returned to within 1% of baseline in the men, but remained
approximately 30% less than baseline in the women (P=0.03). Both sexes displayed
reduced central activation after immobilization (P=0.02), but the decrease was
similar in both sexes (P=0.82). CONCLUSIONS: These findings suggest sex-dependent
adaptations to and recovery from limb immobilization, with voluntary strength
recovering slower in women. As such, sex-specific rehabilitation protocols may be
warranted, with women requiring additional or more intensive rehabilitation
programs after periods of disuse. Future work is needed to determine the extent
and mechanisms of these differences.

Langue : ANGLAIS