Evaluating biomechanics of user-selected sitting and standing computer workstation

• Published in: Applied ergonomics 2017-11, Vol.65, p.382-388
• Main Authors: Lin, Michael Y., Barbir, Ana, Dennerlein, Jack T.
• Format: Article
• Language: English
• Subjects: Adult; Biomechanical Phenomena; Computers; Electromyography; Equipment Design; Ergonomics - methods; Female; Humans; Interior Design and Furnishings - instrumentation; Low Back Pain - etiology; Male; Muscle, Skeletal - physiology; Musculoskeletal Diseases - etiology; Musculoskeletal Diseases - physiopathology; Musculoskeletal disorders; Occupational Diseases - etiology; Occupational Diseases - physiopathology; Office work; Posture - physiology; Shoulder - physiology; Task Performance and Analysis; Upper Extremity - physiology; User-Computer Interface; Work - physiology; Workstation; Wrist - physiology
• ISSN: 0003-6870; 1872-9126
• DOI: 10.1016/j.apergo.2017.04.006

A standing computer workstation has now become a popular modern work place intervention to reduce sedentary behavior at work. However, user's interaction related to a standing computer workstation and its differences with a sitting workstation need to be understood to assist in developing recommendations for use and set up. The study compared the differences in upper extremity posture and muscle activity between user-selected sitting and standing workstation setups. Twenty participants (10 females, 10 males) volunteered for the study. 3-D posture, surface electromyography, and user-reported discomfort were measured while completing simulated tasks with each participant's self-selected workstation setups. Sitting computer workstation associated with more non-neutral shoulder postures and greater shoulder muscle activity, while standing computer workstation induced greater wrist adduction angle and greater extensor carpi radialis muscle activity. Sitting computer workstation also associated with greater shoulder abduction postural variation (90th–10th percentile) while standing computer workstation associated with greater variation for should rotation and wrist extension. Users reported similar overall discomfort levels within the first 10 min of work but had more than twice as much discomfort while standing than sitting after 45 min; with most discomfort reported in the low back for standing and shoulder for sitting. These different measures provide understanding in users' different interactions with sitting and standing and by alternating between the two configurations in short bouts may be a way of changing the loading pattern on the upper extremity. •Users adopt different shoulder and wrist postures between sitting and standing computer workstation.•Users had a more neutral shoulder posture when standing compared to sitting, but had greater wrist extension.•Electromyography also showed lower shoulder muscle load but greater wrist forearm extensor load when standing.•Postural variability for shoulder rotation and wrist extension was greater for standing.•While discomfort was similar at the beginning of the tasks after 45 minutes, users reported higher levels for standing.