title: Sex differences in muscular load among house painters performing identical work tasks.
abstract: OBJECTIVE
  The present study aimed to estimate possible differences in upper body muscular load between male and female house painters performing identical work tasks. Sex-related differences in muscular load may help explain why women, in general, have more musculoskeletal complaints than men.
  
  
  METHODS
  In a laboratory setting, 16 male and 16 female house painters performed nine standardised work tasks common to house painters. Unilateral electromyography (EMG) recordings were obtained from the supraspinatus muscle by intramuscular electrodes and from the trapezius, extensor and flexor carpi radialis muscles by surface electrodes. Relative muscular loads in %EMGmax as well as exerted force in Newton, based on ramp calibrations, were assessed. Sex differences were tested using a mixed model approach.
  
  
  RESULTS
  Women worked at about 50% higher relative muscular loads than men in the supraspinatus and forearm muscles at all percentiles and in all tasks. Women exerted about 30% less force in the trapezius muscle at the 50th percentile.
  
  
  CONCLUSIONS
  Female house painters had a higher relative muscular load than their male colleagues without exerting more force. The effects of a higher relative muscular load accumulated over years of work may in part explain why musculoskeletal complaints in the upper body occur more frequently among women than men.
authors.affiliation: Department of Occupational and Environmental Medicine, Bispebjerg University Hospital, Bispebjerg Bakke 23, 2400, Copenhagen, Denmark, jmeyland@gmail.com.
authors.forename: Jacob
authors.initials: J
authors.lastname: Meyland
authors.forename: Thomas
authors.initials: T
authors.lastname: Heilskov-Hansen
authors.forename: Tine
authors.initials: T
authors.lastname: Alkjær
authors.forename: Henrik
authors.initials: H
authors.lastname: Koblauch
authors.forename: Sigurd
authors.initials: S
authors.lastname: Mikkelsen
authors.forename: Susanne Wulff
authors.initials: SW
authors.lastname: Svendsen
authors.forename: Jane Frølund
authors.initials: JF
authors.lastname: Thomsen
authors.forename: Gert-Åke
authors.initials: GÅ
authors.lastname: Hansson
authors.forename: Erik B
authors.initials: EB
authors.lastname: Simonsen
mesh_terms: D000328:Adult; D001132:Arm / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000502:physiology*; D059352:Musculoskeletal Pain / Q000453:epidemiology / Q000209:etiology; D009790:Occupations; D012737:Sex Factors