Forearm muscle activity by object property and hand posture

The objective of this study was to evaluate forearm muscles activity by commonly used object property and hand posture in manufacturing company and ethology test. A total 10 males of undergraduate and graduate students were recruited in the experiment. The activity (%MVC) of nine forearm muscles was measured using sEMG. The independent variable were hand postures of five levels (2 fingers pinch, 3 fingers pinch 4 fingers pinch, 5 fingers pinch, and 5 fingers grasp), object size of four levels (2, 4, 6, and 8 cm), and object weight of fours level (0.4, 0.8, 1.2, and 1.6 kg). ANOVA showed that hand posture, object size, and weight were statistically significant for all the forearm muscles (p <; 0.001). However, object shape was not statistically significant for all the forearm muscles. The 2 fingers pinch (thumb and index) had a larger muscle activity than the other hand postures for stable pinch. The activities of flexor and extensor muscles increased according to increase object size and weight due to stably grasp. The forearm muscle activity depends on the hand posture and object property. This result can direct future research on hand posture.