Wills M.C.1, Louw Q.1
1University of Stellenbosch, Physiotherapy, Cape Town, South Africa
Background: Persistent upper quadrant musculoskeletal pain and disability are common among female computer workers; they are associated with a complex relationship between individual, work-related and psychosocial factors. Upper quadrant musculoskeletal dysfunction has been associated with reduced work performance. Although there is lack of evidence for an adjustable office chair on computer workers' upper quadrant dysfunction and productivity, an adjustable office chair may provide a platform to change the computer workstation set-up and thereby have an effect on upper quadrant musculoskeletal structures.
Purpose: The aim of this explorative single-study (n=1) was to determine whether an adjustable ergonomic office chair was associated with improvement in self-reported chronic upper quadrant musculoskeletal dysfunction and work productivity among female computer workers, when compared to a less adjustable ergonomic office chair.
Methods: Two single-subject (n=1) withdrawal studies (ABACA) were conducted over a 20 week period. Thereafter, a follow-up phase was conducted five months later. The aim of a single-subject design is to monitor the course of clinical change of the individual between the baseline and intervention phases, with participants acting as their own controls. Self-reported outcome measures included: visual analogue scale (measuring intensity and frequency of upper quadrant musculoskeletal pain and muscle tension), Neck Disability Index and Work Productivity and Impairment questionnaire. As this study focused on individual clinical changes in a real-life work environment, it is more appropriate to measure subjective outcomes than physiological outcomes for upper quadrant musculoskeletal dysfunction.
The intervention study and placebo ergonomic office chairs were blinded and randomly allocated to each participant during each intervention phase. No changes were made to workstations, other than to adjustable features of intervention ergonomic office chairs. Data was analysed visually, descriptive statistics (mean and standard deviation) were applied to each participant per phase.
Results: Results found a clinically meaningful short-term reduction in both participants self-reported upper quadrant pain and perceived muscle tension. One participants results showed a clinically meaningful reduction in self-reported neck disability and work impairment, resulting from upper quadrant musculoskeletal dysfunction. The other participants baseline values for these outcomes were too low for meaningful comparison.
Conclusion(s): Study findings indicate that in the short term a height adjustable ergonomic office chair reduced upper quadrant musculoskeletal dysfunction in two female computer workers with chronic upper quadrant work related musculoskeletal dysfunction. The reduction in self-reported pain intensity on the visual analogue scale was clinically meaningful for both participants, during the study and the follow-up period, five months after study completion.
Implications: The findings from this explorative study can be used as a foundation for further studies to include larger samples of computer workers, with greater work impairments, in different work environments and over a longer time period. It is recommended that future research should further investigate the association between work related upper quadrant musculoskeletal dysfunction and adjustable chair features. The implications could contribute to future recommendations for computer workers regarding office chair adjustability, to reduce work related upper quadrant musculoskeletal dysfunction.
Funding acknowledgements: The intervention chairs were funded by the Harry Crossley foundation
Topic: Occupational health & ergonomics
Ethics approval: Ethics approval was obtained from the Committee for Human Research at Stellenbosch University.
All authors, affiliations and abstracts have been published as submitted.
