The effect of walking while typing on neck/shoulder patterns
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This project aimed to quantify the effects of modifying computer work posture on neck/shoulder patterns during a prolonged typing task.
Twenty healthy participants completed a 90-min typing task while sitting or walking on a treadmill. Electromyography (EMG) was recorded from eight upper body muscles and laser Doppler flowmetry (LDF) from two upper body sites. Effects of Time and Posture were assessed for EMG amplitude (RMS), variability (CoV), normalized mutual information (NMI), LDF and upper limb discomfort.
Upper limb discomfort was higher during sitting and increased with time, from 0.86 ± 1.3 to 3.7 ± 3.1 out of 10. Interaction effects showed that EMG amplitude decreased over time for the lumbar erector spinae (LES) (from 6.3 ± 2.9 to 5.6 ± 3.2 % MIVC) and wrist extensor (from 12.4 ± 2.7 to 11.3 ± 3.5 % MIVC) during walking, but increased during sitting. Anterior Deltoid EMG amplitude was 64 % lower during walking while External Oblique EMG amplitude (43 %) and Lower Trapezius EMG variability (65 %) were higher during walking. Interaction effects showed higher LES CoV during walking compared to sitting (p = 0.019) in the beginning but not at the end of the task, and higher neck/shoulder NMI (p = 0.050) towards the end of the task during sitting compared to walking.
Results suggest that walking while performing computer work may be effective in inducing healthier muscular patterns, possibly explaining the lower level of discomfort compared to sitting.
KeywordsDiscomfort Computer work EMG Treadmill Neck/shoulder Blood flow
Analysis of variance
Adjusted words per minute
Cervical erector spinae
Coefficient of variation
Forearm laser Doppler flowmetry
Laser Doppler flowmetry
Lumbar erector spinae
Maximum isometric voluntary contractions
Normalized mutual information
Perceived stress scale
Shoulder laser Doppler flowmetry
Work-related musculoskeletal disorder
In addition to the participants in the study, the authors wish to thank David Antle, Amanda Farias and Zach Weber for their assistance in data collection and analyses. This research was supported by grant Grants from the Canadian Foundation for Innovation and the Institut de Recherche Robert-Sauvé en Santé etenSécurité du Travail (IRSST). Julie Côté holds a Gender, Work and HealthResearch Chair from the Canadian Institutes for HealthResearch and the IRSST.
Conflict of interest
No author has financial or personal conflicts of interest that could inappropriately influence their work.
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