Effect of brief daily resistance training on occupational neck/shoulder muscle activity in office workers with chronic pain: randomized controlled trial.
OBJECTIVE
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 (n = 15) or in control receiving weekly email-based information on general health (n = 15). 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% (P < 0.05) and decreased neck/shoulder pain intensity by 40% (P < 0.01). 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.


CONCLUSIONS
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.
National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen Ø, Denmark.
Mark
M
Lidegaard
National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen Ø, Denmark.
Rene B
RB
Jensen
National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen Ø, Denmark.
Christoffer H
CH
Andersen
Gait Analysis Laboratory, Copenhagen University Hospital Hvidovre, Kettegaard Alle 30, 2650 Hvidovre, Denmark.
Mette K
MK
Zebis
Research Group in Sport and Health, Laboratory of Physical Activity and Health, University of Valencia, 46010 Valencia, Spain.
Juan C
JC
Colado
Department of Rehabilitation Medicine, The Sixth Affiliated Hospital of Sun Yat-sen University, No. 26, Yuancun 2nd Cross Road, Guangzhou 510655, China.
Yuling
Y
Wang
Department of Occupational and Environmental Medicine, Bispebjerg University Hospital, Bispebjerg Bakke 23, 2400 Copenhagen NV, Denmark.
Thomas
T
Heilskov-Hansen
National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen Ø, Denmark.
Lars L
LL
Andersen
D000328:Adult; D059350:Chronic Pain / Q000473:pathology / Q000628:therapy*; D005260:Female; D006801:Humans; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000473:pathology; D009333:Neck / Q000473:pathology; D055070:Resistance Training; D012782:Shoulder / Q000473:pathology