Analysis of neck and shoulder postures, and muscle activities relative to perceived pain during laptop computer use at a low-height table, sofa and bed.

BACKGROUND

Laptop computers are used in various places and situations. The number of laptop users experiencing musculoskeletal disorders (MSDs) has increased drastically due to, in part, inappropriate workstations.

OBJECTIVE

To investigate the neck and shoulder postures, and muscle activity relative to perceived pain when using the laptop at a low-height table, sofa, and bed.

METHODS

Twenty male participants aged 18-25 years were randomly assigned to perform laptop computer operation at 3 workstations for 10 minutes during which neck and shoulder angles, muscle activity, and pain were recorded by using an Electrogoniometer, Electromyography (EMG), and visual analog scale (VAS), respectively.

RESULTS

Neck flexions when working at the sofa (18.6°±12.2°) and bed (17.2°±10.5°) were significantly (p < 0.05) greater than that at the low-height table (7.8°±6.5°). However, shoulder flexion when working at the low-height table (28.2°±13.0°) was significantly (p < 0.05) greater than that at the sofa (13.8°±8.6°) and bed (10.91°±7.8°). Working at the low-height table caused the shoulder flexor muscle activity to be significantly (p < 0.05) higher than working at the sofa and bed. Neck pain was reported during laptop computer use at the sofa and bed, and upper back pain when working at the low-height table.

CONCLUSIONS

High neck flexion and pain were found while working at sofa and bed, whereas high muscle activity at shoulder and upper back pain were found while working at the low-height table.