Determination of the key workposture and muscle fatigue measurements for the ergonomic design of coconut grater using SEMG

Abstract

This study aims to ergonomically validate the most commonly used coconut graters that are available in the Indian market. The study mainly evaluates the muscle loading in the upper limb during the coconut grinding process at different working posture using surface electromyography (SEMG). Twelve volunteers participated in the experimental trial and performed coconut grinding operations using three different commercially available graters. During the trial, their hand muscle activities are recorded using EMG sensors at two commonly adopted work posture (sitting and squatting). Mean power frequency (MPF) and root mean square (RMS) values are extracted from EMG signals to find the muscle fatigue and engagement during the grating process. Results revealed that grater 3 showed less muscle fatigue and muscle loading compared to graters 1 and 2. Sitting posture is more effective than squatting posture in terms of reducing muscle fatigue. Flexor carpi radialis (FCR) right and left are more engaged during the coconut grating process compared to extensor carpi radialis (ECR) right and left.