title: Electromyography as a measure of peak and cumulative workload in intermediate care and its relationship to musculoskeletal injury: an exploratory ergonomic study.
abstract: Injury rates in Intermediate Care (IC) facilities are high and the factors related to these injuries are unclear. The objectives of this exploratory sub-study, which is part of a large multi-faceted study in 8 IC facilities are to: (1) evaluate EMG measured over a full-shift in the back and shoulders of 32 care aides (CAs) as an indicator of peak and cumulative workload (n = 4 x 8 facilities); investigate the relationship between EMG measures and injury indicators; and explore the relationship between EMG measures and other workload measurements. Lumbar EMG was converted to predicted cumulative spinal compression and ranged in CAs from 11.7 to 22.8 MNs with a mean of 16.4 MNs. Average compression was significantly different during different periods of the day (p < 0.001) with highest compression during pre-breakfast when CAs assist most with activities of daily living. Significant differences were found in average compression between low and high injury facilities for 3 of 5 periods of the day (p < 0.010). Peak compressions exceeding 3400 N occurred for very little of the workday (e.g. 11.25s during the 75 min period pre-breakfast). Peak neck/shoulder muscle activity is low (99% APDF ranged from 8.33% to 28% MVC). Peak and cumulative spinal compression were significantly correlated with lost-time and musculoskeletal injury rates as well as with total tasks observed in the CAs (p < 0.01). Perceived exertion was only correlated with peak compressions (p < 0.01). Facilities with low injury rates provided significantly more CAs (p < 0.01) to meet resident needs, and subsequently CAs performed fewer tasks, resulting in less peak and cumulative spinal loading over the day.
authors.affiliation: School of Occupational and Environmental Hygiene, University of British Columbia (UBC), Vancouver, BC, Canada. village@interchange.ubc.ca
authors.forename: J
authors.initials: J
authors.lastname: Village
authors.forename: M
authors.initials: M
authors.lastname: Frazer
authors.forename: M
authors.initials: M
authors.lastname: Cohen
authors.forename: A
authors.initials: A
authors.lastname: Leyland
authors.forename: I
authors.initials: I
authors.lastname: Park
authors.forename: A
authors.initials: A
authors.lastname: Yassi
mesh_terms: D001415:Back / Q000503:physiopathology; D019567:Back Injuries / Q000175:diagnosis* / Q000503:physiopathology; D001955:British Columbia; D004576:Electromyography / Q000379:methods; D006804:Ergonomics / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009140:Musculoskeletal Diseases / Q000175:diagnosis* / Q000503:physiopathology; D009728:Nursing Assistants; D009784:Occupational Diseases / Q000175:diagnosis* / Q000503:physiopathology; D012307:Risk Factors; D012782:Shoulder / Q000503:physiopathology; D000070599:Shoulder Injuries; D018582:Sick Leave; D016526:Workload