Muscular and cold strain of female workers in meatpacking work

Abstract

The purpose of this cross-sectional study was to investigate muscular strain and thermal responses of female workers during meatpacking work in cooled departments in a large meat processing factory. The measurements were performed among 18 healthy women during their normal work tasks at a temperature of 4–10 °C. Muscular strain in upper extremities and the shoulder region was measured by continuous electromyography (EMG). Relative muscular strain was calculated from EMG activity during work in relation to maximal EMG activity measured during maximal voluntary contraction. Skin and rectal temperatures were measured continuously. The results showed that muscular strain was the highest in wrist extensor muscles (m. extensor digitorum), being 16–18% of the maximal EMG activity (% MEMG), while the respective values in wrist flexor muscles (m. flexor carpi radialis) were 8–12% MEMG and in the shoulder region, 6–7% MEMG in the medial part of m. deltoideus and 8–14% MEMG in the descending part of m. trapezius. Working in cooled departments decreased skin temperatures most in the shoulder region, fingers and lower extremities. However, the association between skin temperatures and muscular strain was not statistically significant. It can be concluded that muscular strain was mainly related to the intensity of repetitive work movements. Relevance to industry The results suggests that in industries where repetitive manual work and cold are combined, preventive measures such as improvements in cold protective clothing and ergonomic interventions in repetitive work tasks might be considered to prevent cooling and to reduce upper extremity muscular strain.