Variation in upper trapezius and wrist extensor EMG among office workers during sit-stand table use in a real work setting

• Background: Computer work is generally associated with constrained postures and low muscular demands. Sit-stand tables have been suggested as an effective initiative to change working postures during computer work, but the effect of this intervention on muscle activation has rarely been studied. The aim of this study was to document variation in shoulder-arm muscle activation among office workers using sit-stand tables.Methods: Twenty-four office workers (16 females, 8 males; age 41±9 years) participated. At entry, workers received sit-stand tables and ergonomics information, and then used the table for two months. Muscle activity of right and left upper trapezius and wrist extensors (RUT, LUT, RWE and LWE, respectively) was recorded during three consecutive days (two hours each day) in the last week of sit-stand table usage. Periods of computer work in sitting and standing positions (CWsit and CWstand, respectively) were identified by on-site observation, and synchronized with the EMG recordings. Variability (min-min SD across 1-minute bins, %MVE) was calculated for each EMG recording in CWsit and CWstand.Results: During the 62 minutes of EMG recorded during computer work, CWsit was performed for 72% and CWstand for 28% of the time. The mean minute-to-minute variability of trapezius EMG was larger (P<0.05) during CWsit (RUT 3.9 (SD between workers 1.6) %MVE; LUT 3.9 (SD 2.3) %MVE) than CWstand (RUT 3.0 (SD 1.5) %MVE; LUT 3.2 (SD 1.9) %MVE). The mean minute-to minute variability in RWE was also larger during CWsit (3.3 (SD 1.4) %MVE) than CWstand (2.9 (SD 1.3) %MVE). For LWE, variability did not differ between CWsit and CWstand.Conclusion: Sitting and standing computer work was associated with different extents of variation in shoulder-arm muscle activity. Thus, sit-stand tables may introduce beneficial exposure variation into the work of office employees.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Hälsovetenskap -- Arbetsmedicin och miljömedicin (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Health Sciences -- Occupational Health and Environmental Health (hsv//eng)

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Digital shapeshifting

Digital shapeshifting

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