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BioMed Research International
Volume 2016 (2016), Article ID 4137918, 11 pages
http://dx.doi.org/10.1155/2016/4137918
Clinical Study

Strength Training Improves Fatigue Resistance and Self-Rated Health in Workers with Chronic Pain: A Randomized Controlled Trial

1National Research Centre for the Working Environment, Copenhagen, Denmark
2Department of Sports Science and Clinical Biomechanics, SDU Muscle Research Cluster, University of Southern Denmark, Odense, Denmark
3Physical Activity and Human Performance Group, SMI, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
4The Carrick Institute, Clinical Neuroscience and Rehabilitation, Cape Canaveral, FL 32920, USA

Received 6 July 2016; Revised 13 September 2016; Accepted 20 September 2016

Academic Editor: Leonardo F. Ferreira

Copyright © 2016 Emil Sundstrup et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Chronic musculoskeletal pain is widespread in the working population and leads to muscular fatigue, reduced work capacity, and fear of movement. While ergonomic intervention is the traditional approach to the problem, physical exercise may be an alternative strategy. This secondary analysis of a randomized controlled trial investigates the effect of strength training on muscular fatigue resistance and self-rated health among workers with chronic pain. Sixty-six slaughterhouse workers with chronic upper limb pain and work disability were randomly allocated to 10 weeks of strength training or usual care ergonomic training (control). At baseline and follow-up, participants performed a handgrip muscular fatigue test (time above 50% of maximal voluntary contraction force) with simultaneous recording of electromyography. Additionally, participants replied to a questionnaire regarding self-rated health and pain. Time to fatigue, muscle strength, hand/wrist pain, and self-rated health improved significantly more following strength training than usual care (all ). Time to fatigue increased by 97% following strength training and this change was correlated to the reduction in fear avoidance (Spearman’s rho ; ). In conclusion, specific strength training improves muscular fatigue resistance and self-rated health and reduces pain of the hand/wrist in manual workers with chronic upper limb pain. This trial is registered with ClinicalTrials.gov NCT01671267.