Electromyography (EMG) and Hand Gripping Force During Standing and Sitting

Musculoskeletal disorders reduced the motion and strength of upper limb muscle, especially when doing a task repeatedly. Evaluation of upper limb muscle strength has been commonly conducted using hand grip strength measurement. Previous studies had explored Electromyography (EMG) and hand grip strength but when studies related body postures, only hand grip strength method was considered. However, previous studies involved the effect of body postures on upper limb muscle strength only focused on hand grip strength method, not EMG. The aim of this study is to investigate the effect of EMG time domain during standing and sitting while gripping in order to identify the postures that are riskier for musculoskeletal injuries. Three feature extraction namely root mean square (RMS), mean absolute variance (MAV), and variance (VAR) were used to represent the EMG. Based on the result, the responses of 0.118 μV, 0.0613 μV, and 0.0139 μV were recorded at sitting position while 0.1455 μV, 0.0843 μV, and 0.0148 μV were recorded at standing position, for respective feature extractions. It shows that the response value of EMG changed for different body postures. To conclude, the body posture is crucial when conducting the upper limb studies for both hand grip strength measurement and EMG.