title: Effect of two contrasting interventions on upper limb chronic pain and disability: a randomized controlled trial.
abstract: BACKGROUND
  Chronic pain and disability of the arm, shoulder, and hand severely affect labor market participation. Ergonomic training and education is the default strategy to reduce physical exposure and thereby prevent aggravation of pain. An alternative strategy could be to increase physical capacity of the worker by physical conditioning.
  
  
  OBJECTIVE
  To investigate the effect of 2 contrasting interventions, conventional ergonomic training (usual care) versus resistance training, on pain and disability in individuals with upper limb chronic pain exposed to highly repetitive and forceful manual work.
  
  
  METHODS
  Examiner-blinded, parallel-group randomized controlled trial with allocation concealment.
  
  
  METHODS
  Slaughterhouses located in Denmark, Europe.
  
  
  METHODS
  Sixty-six adults with chronic pain in the shoulder, elbow/forearm, or hand/wrist and work disability were randomly allocated to 10 weeks of specific resistance training for the shoulder, arm, and hand muscles for 3 x 10 minutes per week, or ergonomic training and education (usual care control group). Pain intensity (average of shoulder, arm, and hand, scale 0 - 10) was the primary outcome, and disability (Work module of DASH questionnaire) as well as isometric shoulder and wrist muscle strength were secondary outcomes.
  
  
  RESULTS
  Pain intensity, disability, and muscle strength improved more following resistance training than usual care (P < 0.001, P = 0.05, P <0.0001, respectively [corrected]). Pain intensity decreased by 1.5 points (95% confidence interval -2.0 to -0.9) following resistance training compared with usual care, corresponding to an effect size of 0.91 (Cohen's d).
  
  
  CONCLUSIONS
  Blinding of participants is not possible in behavioral interventions. However, at baseline outcome expectations of the 2 interventions were similar.
  
  
  CONCLUSIONS
  Resistance training at the workplace results in clinical relevant improvements in pain, disability, and muscle strength in adults with upper limb chronic pain exposed to highly repetitive and forceful manual work.
  
  
  BACKGROUND
  NCT01671267.
authors.affiliation: National Research Centre for the Working Environment,Copenhagen, Denmark.
authors.forename: Emil
authors.initials: E
authors.lastname: Sundstrup
authors.forename: Markus D
authors.initials: MD
authors.lastname: Jakobsen
authors.forename: Christoffer H
authors.initials: CH
authors.lastname: Andersen
authors.forename: Kenneth
authors.initials: K
authors.lastname: Jay
authors.forename: Roger
authors.initials: R
authors.lastname: Persson
authors.forename: Per
authors.initials: P
authors.lastname: Aagaard
authors.forename: Lars L
authors.initials: LL
authors.lastname: Andersen
mesh_terms: D000328:Adult; D059350:Chronic Pain / Q000503:physiopathology* / Q000534:rehabilitation*; D006233:Persons with Disabilities / Q000534:rehabilitation*; D006804:Ergonomics / Q000379:methods*; D005081:Exercise Therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D010147:Pain Measurement; D055070:Resistance Training / Q000379:methods*; D016037:Single-Blind Method; D016896:Treatment Outcome; D034941:Upper Extremity / Q000503:physiopathology