title: Neck-shoulder muscle activity in general and task-specific resting postures of symptomatic computer users with chronic neck pain.
abstract: Past research on work-related musculoskeletal disorders (WMSD) has frequently examined the activity of neck-shoulder muscles such as upper trapezius (UT) and cervical erector spinae (CES) during typing tasks. Increased electromyographic activity in these postural stabilising muscles has been consistently found in chronic neck pain patients under different physically stressful conditions. The present study compared muscle activity when female office workers with chronic neck pain (n=39) and asymptomatic controls (n=34) adopted two resting postures: (1) with hands on laps versus; and (2) hands on a keyboard. Resting hands on keyboard elicited significantly increased muscle activity in the right UT of subjects with high discomforts (n=22), similar to that observed during actual typing. In contrast, the asymptomatic controls showed no difference in muscle activity between the resting postures. This result suggested that altered muscle activation patterns were triggered by some anticipatory task demand associated with a task-specific position in some individuals.
authors.affiliation: Department of Rehabilitation Sciences, Hong Kong Polytechnic University, Hong Kong SAR, China. rsgszeto@polyu.edu.hk
authors.forename: Grace Pui Yuk
authors.initials: GP
authors.lastname: Szeto
authors.forename: Leon Melville
authors.initials: LM
authors.lastname: Straker
authors.forename: Peter Bruce
authors.initials: PB
authors.lastname: O'Sullivan
mesh_terms: D000328:Adult; D002574:Cervical Vertebrae / Q000502:physiology*; D002908:Chronic Disease; D003201:Computers; D004185:Disability Evaluation; D004576:Electromyography / Q000379:methods; D005260:Female; D006801:Humans; D008875:Middle Aged; D009334:Neck Muscles / Q000502:physiology*; D019547:Neck Pain / Q000175:diagnosis / Q000503:physiopathology*; D009784:Occupational Diseases / Q000175:diagnosis / Q000503:physiopathology*; D011187:Posture; D016059:Range of Motion, Articular; D013647:Task Performance and Analysis; D016526:Workload