A study on the activation of forearm muscles during gripping by handle thickness

Abstract

[Purpose] This study examined the muscle activation when subjects gripped a handle with a circumference equal to 0%, 25%, 50%, 75%, or 100% of their hand length to determine the size that can be gripped most stably relative to the hand length. [Subjects and Methods] The muscle activation of 34 subjects was measured using electromyography. To make a cylinder proportionate to the hand length, multiple pencils were combined and the circumference was measured with a tape measure. The cylinders were made with circumferences of 0%, 25%, 50%, 75%, and 100% of the hand length. [Results] The largest muscle activation was observed at handle circumferences of 50% and 75% of the hand length in the wrist extensor bundle and at 75% of the hand length in the flexor digitorum superficialis. [Conclusion] Therefore, circumferences of the middle range of hand length seems to be most appropriate for hammer handles and handles with high resistance which require large strength at industrial sites.