Implementation of Physical Exercise at the Workplace (IRMA06) - Slaughterhouse Workers (IRMA)

The prevalence of pain in the shoulder, arm and hand is high among slaughterhouse workers, allegedly due to the substantial load of these body regions during work. Work disability is a common consequence of these pains. Lowering the physical exposure through ergonomic intervention may be a strategy to reduce the workload. An alternative strategy could be to increase the physical capacity through strength training of the shoulder-, arm- and hand-muscles. This study investigates the effect of two contrasting interventions, i.e. load reduction (ergonomic intervention) versus training of physical capacity (strength training) on pain and work disability in slaughterhouse workers. The main hypothesis is that strength training intervention for 10 weeks compared with ergonomic intervention results in reduced pain of the shoulder, arm and hand.

The change in "pain intensity during the last week" (average value of shoulder, elbow and hand) from baseline to 10 week follow-up between the strength training group and ergonomic group. The ergonomic group will be considered the reference group. 2-way analysis of variance (Proc Mixed of SAS) with repeated measures will be used, with time and group as fixed factors and subject as random factor.

Disability of the arm, shoulder and hand questionnaire (DASH). Only the work-module of DASH will be included. Analyzed the same way as the primary outcome.

Pressure pain threshold of the muscle of the forearm, external rotators of the shoulder, and tibialis anterior of the leg (reference muscle).

change in examiner-verified tenderness of the muscles of the shoulder, arm and hand. Scale of "no", "a little", "moderate" and "severe" tenderness. Summed up to a total tenderness score (Andersen LL 2011, PMID: 21177034)

Inclusion Criteria: Slaughterhouse worker the pain should have lasted at least 3 months pain intensity during the last three months of >= 3 (scale 0-10) in the shoulder, elbow or hand the pain should be frequent (at least 3 days per week) Exclusion Criteria: life threatening disease pregnancy

Sundstrup E, Jakobsen MD, Brandt M, Jay K, Aagaard P, Andersen LL. Strength Training Improves Fatigue Resistance and Self-Rated Health in Workers with Chronic Pain: A Randomized Controlled Trial. Biomed Res Int. 2016;2016:4137918. doi: 10.1155/2016/4137918. Epub 2016 Oct 17.

Sundstrup E, Jakobsen MD, Andersen CH, Jay K, Persson R, Aagaard P, Andersen LL. Effect of two contrasting interventions on upper limb chronic pain and disability: a randomized controlled trial. Pain Physician. 2014 Mar-Apr;17(2):145-54. Erratum In: Pain Physician. 2014 May-Jun;17(3):E275.

Sundstrup E, Jakobsen MD, Andersen CH, Jay K, Persson R, Aagaard P, Andersen LL. Participatory ergonomic intervention versus strength training on chronic pain and work disability in slaughterhouse workers: study protocol for a single-blind, randomized controlled trial. BMC Musculoskelet Disord. 2013 Feb 21;14:67. doi: 10.1186/1471-2474-14-67.