title: Influence of frequency and duration of strength training for effective management of neck and shoulder pain: a randomised controlled trial.
abstract: BACKGROUND
  Specific strength training can reduce neck and shoulder pain in office workers, but the optimal combination of exercise frequency and duration remains unknown. This study investigates how one weekly hour of strength training for the neck and shoulder muscles is most effectively distributed.
  
  
  METHODS
  A total of 447 office workers with and without neck and/or shoulder pain were randomly allocated at the cluster-level to one of four groups; 1×60 (1WS), 3×20 (3WS) or 9×7 (9WS) min a week of supervised high-intensity strength training for 20 weeks, or to a reference group without training (REF). Primary outcome was self-reported neck and shoulder pain (scale 0-9) and secondary outcome work disability (Disability in Arms, Shoulders and Hands (DASH)).
  
  
  RESULTS
  The intention-to-treat analysis showed reduced neck and right shoulder pain in the training groups after 20 weeks compared with REF. Among those with pain ≥3 at baseline (n=256), all three training groups achieved significant reduction in neck pain compared with REF (p<0.01). From a baseline pain rating of 3.2 (SD 2.3) in the neck among neck cases, 1WS experienced a reduction of 1.14 (95% CI 0.17 to 2.10), 3WS 1.88 (0.90 to 2.87) and 9WS 1.35 (0.24 to 2.46) which is considered clinically significant. DASH was reduced in 1WS and 3WS only.
  
  
  CONCLUSIONS
  One hour of specific strength training effectively reduced neck and shoulder pain in office workers. Although the three contrasting training groups showed no statistical differences in neck pain reduction, only 1WS and 3WS reduced DASH. This study suggests some flexibility regarding time-wise distribution when implementing specific strength training at the workplace.
authors: National Research Centre for the Working Environment, Copenhagen, Denmark. cha@nrcwe.dk
authors: Christoffer H
authors: CH
authors: Andersen
authors: Lars L
authors: LL
authors: Andersen
authors: Bibi
authors: B
authors: Gram
authors: Mogens Theisen
authors: MT
authors: Pedersen
authors: Ole Steen
authors: OS
authors: Mortensen
authors: Mette Kreutzfeldt
authors: MK
authors: Zebis
authors: Gisela
authors: G
authors: Sjøgaard
mesh_terms: D016000:Cluster Analysis; D006233:Persons with Disabilities; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology; D019547:Neck Pain / Q000534:rehabilitation*; D010349:Patient Compliance; D055070:Resistance Training / Q000379:methods*; D020069:Shoulder Pain / Q000503:physiopathology / Q000534:rehabilitation*; D013997:Time Factors; D016896:Treatment Outcome