Alterations in cervical muscle activity in functional and stressful tasks in female office workers with neck pain.
This study determined differences between computer workers with varying levels of neck pain in terms of work stressors, employee strain, electromyography (EMG) amplitude and heart rate response to various tasks. Participants included 85 workers (33, no pain; 38, mild pain; 14, moderate pain) and 22 non-working controls. Work stressors evaluated were job demands, decision authority, and social support. Heart rate was recorded during three tasks: copy-typing, typing with superimposed stress and a colour word task. Measures included electromyography signals from the sternocleidomastoid (SCM), anterior scalene (AS), cervical extensor (CE) and upper trapezius (UT) muscles bilaterally. Results showed no difference between groups in work stressors or employee strain measures. Workers with and without pain had higher measured levels of EMG amplitude in SCM, AS and CE muscles during the tasks than controls (all P < 0.02). In workers with neck pain, the UT had difficulty in switching off on completion of tasks compared with controls and workers without pain. There was an increase in heart rate, perceived tension and pain and decrease in accuracy for all groups during the stressful tasks with symptomatic workers producing more typing errors than controls and workers without pain. These findings suggest an altered muscle recruitment pattern in the neck flexor and extensor muscles. Whether this is a consequence or source of the musculoskeletal disorder cannot be determined from this study. It is possible that workers currently without symptoms may be at risk of developing a musculoskeletal disorder.
Johnston
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V
Physiotherapy Division, School of Health and Rehabilitation Sciences, The University of Queensland, Level 7, Therapies Building 84A, St Lucia, QLD 4072, Australia. v.johnston@shrs.uq.edu.au
Jull
G
G
Darnell
R
R
Jimmieson
N L
NL
Souvlis
T
T
D000328:Adult; D003201:Computers; D003430:Cross-Sectional Studies; D003657:Decision Making; D004185:Disability Evaluation; D004576:Electromyography; D005260:Female; D019416:Head Movements; D006339:Heart Rate; D006801:Humans; D008875:Middle Aged; D009334:Neck Muscles / Q000503:physiopathology*; D019547:Neck Pain / Q000503:physiopathology* / Q000523:psychology; D009784:Occupational Diseases / Q000503:physiopathology* / Q000523:psychology; D010147:Pain Measurement; D012720:Severity of Illness Index; D012944:Social Support; D013315:Stress, Psychological / Q000503:physiopathology*; D011795:Surveys and Questionnaires; D015443:Word Processing; D016526:Workload