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BioMed Research International
Volume 2013 (2013), Article ID 262386, 11 pages
http://dx.doi.org/10.1155/2013/262386
Research Article

Effect of Brief Daily Resistance Training on Occupational Neck/Shoulder Muscle Activity in Office Workers with Chronic Pain: Randomized Controlled Trial

1National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen Ø, Denmark
2Gait Analysis Laboratory, Copenhagen University Hospital Hvidovre, Kettegaard Alle 30, 2650 Hvidovre, Denmark
3Research Group in Sport and Health, Laboratory of Physical Activity and Health, University of Valencia, 46010 Valencia, Spain
4Department of Rehabilitation Medicine, The Sixth Affiliated Hospital of Sun Yat-sen University, No. 26, Yuancun 2nd Cross Road, Guangzhou 510655, China
5Department of Occupational and Environmental Medicine, Bispebjerg University Hospital, Bispebjerg Bakke 23, 2400 Copenhagen NV, Denmark

Received 2 October 2013; Revised 19 November 2013; Accepted 4 December 2013

Academic Editor: Brad J. Schoenfeld

Copyright © 2013 Mark Lidegaard 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

Purpose. This study investigates the acute and longitudinal effects of resistance training on occupational muscle activity in office workers with chronic pain. Methods. 30 female office workers with chronic neck and shoulder pain participated for 10 weeks in high-intensity elastic resistance training for 2 minutes per day ( ) or in control receiving weekly email-based information on general health ( ). Electromyography (EMG) from the splenius and upper trapezius was recorded during a normal workday. Results. Adherence to training and control interventions were 86% and 89%, respectively. Compared with control, training increased isometric muscle strength 6% ( ) and decreased neck/shoulder pain intensity by 40% ( ). The frequency of periods with complete motor unit relaxation (EMG gaps) decreased acutely in the hours after training. By contrast, at 10-week follow-up, training increased average duration of EMG gaps by 71%, EMG gap frequency by 296% and percentage time below 0.5%, and 1.0% EMGmax by 578% and 242%, respectively, during the workday in m. splenius. Conclusion. While resistance training acutely generates a more tense muscle activity pattern, the longitudinal changes are beneficial in terms of longer and more frequent periods of complete muscular relaxation and reduced pain.