title: Restoration of voluntary muscle strength after 3 weeks of cast immobilization is suppressed in women compared with men.
abstract: OBJECTIVE
  To investigate sex-related differences in the loss and recovery of voluntary muscle strength after immobilization.
  
  
  METHODS
  Longitudinal, repeated measures.
  
  
  METHODS
  Research laboratory.
  
  
  METHODS
  Healthy men (n=5) and healthy women (n=5).
  
  
  METHODS
  Three weeks of forearm immobilization.
  
  
  METHODS
  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.
authors.affiliation: Interdisciplinary Institute for Neuromusculoskeletal Research, Department of Biomedical Sciences, Ohio University, Athens, OH 45701, USA. clarkb2@ohio.edu
authors.forename: Brian C
authors.initials: BC
authors.lastname: Clark
authors.forename: Todd M
authors.initials: TM
authors.lastname: Manini
authors.forename: Richard L
authors.initials: RL
authors.lastname: Hoffman
authors.forename: David W
authors.initials: DW
authors.lastname: Russ
mesh_terms: D000222:Adaptation, Physiological; D000293:Adolescent; D000328:Adult; D005260:Female; D005542:Forearm; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D053580:Muscle Strength; D009133:Muscular Atrophy / Q000209:etiology / Q000534:rehabilitation*; D020127:Recovery of Function; D012046:Rehabilitation / Q000379:methods*; D012149:Restraint, Physical; D012737:Sex Factors; D055815:Young Adult