title: Gender differences in fatigability and muscle activity responses to a short-cycle repetitive task.
abstract: OBJECTIVE
  Epidemiological research has identified women to be more susceptible to developing neck-shoulder musculoskeletal disorders when performing low-force, repetitive work tasks. Whether this is attributable to gender differences in fatigability and motor control is currently unclear. This study investigated the extent to which women differ from men in fatigability and motor control while performing a short-cycle repetitive task.
  
  
  METHODS
  113 healthy young adults (58 women, 55 men) performed a standardized repetitive pointing task. The task was terminated when the subject's perceived exertion reached 8 on the Borg scale. The time to task termination, and changes in means and cycle-to-cycle variabilities of surface electromyography signals from start to end of the task, were compared between women and men, for the upper trapezius, anterior deltoid, biceps and triceps muscles.
  
  
  RESULTS
  Women and men terminated the task after 6.5 (SD 3.75) and 7 (SD 4) min on average (p > 0.05). All four muscles showed an increase of 25-35 % in average muscle activity with fatigue (no significant sex differences). However, men exhibited a higher increase than women in trapezius muscle variability with fatigue (31 vs. 7 %; p < 0.05), and a decrease in biceps muscle variability where women had an increase (-23 vs. 12 %; p < 0.05).
  
  
  CONCLUSIONS
  Our results suggest that women and men may not differ in the ability to perform repetitive tasks at low-to-moderate force levels. However, differences in motor control strategies employed in task performance may explain gender differences in susceptibility to developing musculoskeletal disorders when performing repetitive work for prolonged periods in occupational life.
authors.affiliation: Department of Occupational and Public Health Sciences, Centre for Musculoskeletal Research, University of Gavle, 801 76, Gavle, Sweden. sdivya1@vt.edu.|Grado Department of Industrial and Systems Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24060, USA. sdivya1@vt.edu.
authors.forename: Divya
authors.initials: D
authors.lastname: Srinivasan
authors.affiliation: McGill University, 475 Pine Avenue West, Montreal, QC, H2W 1S4, Canada.|CRIR Research Centre, Jewish Rehabilitation Hospital, 3205 Alton Goldbloom Place, Laval, QC, H7V-1R2, Canada.
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: Sinden
authors.affiliation: Department of Occupational and Public Health Sciences, Centre for Musculoskeletal Research, University of Gavle, 801 76, Gavle, Sweden.
authors.forename: Svend Erik
authors.initials: SE
authors.lastname: Mathiassen
authors.affiliation: McGill University, 475 Pine Avenue West, Montreal, QC, H2W 1S4, Canada.|CRIR Research Centre, Jewish Rehabilitation Hospital, 3205 Alton Goldbloom Place, Laval, QC, H7V-1R2, Canada.
authors.forename: Julie N
authors.initials: JN
authors.lastname: Côté
mesh_terms: D000328:Adult; D005221:Fatigue / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D009068:Movement; D009119:Muscle Contraction; D018763:Muscle Fatigue; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000503:physiopathology*; D005082:Physical Exertion; D011597:Psychomotor Performance; D012737:Sex Factors
keywords: Cycle-to-cycle variability; Motor control; Motor variability; Multi-jointed movements; Pointing movement; Shoulder–elbow coordination