Evaluation of Shoulder Risk Factors in the Repetitive Task of Slaughterhouse

Abstract

Repetitive movements and the speed of upper limbs increase the risk of musculoskeletal disorders. This study aimed to analyse the risk of shoulder injuries in repetitive tasks by evaluating the humerus angle, angular velocity, and angular acceleration during simulated chicken wing cutting. The study was conducted in a laboratory simulating a real environment. Thirty-six healthy right-handed volunteers were assessed using an electromagnetic tracking device, TrakSTAR, integrated with MotionMonitor™ (Innovative Sports Training, Inc. Chicago, IL) and software to collect 3-D kinematic data developed in the research centre. The equipment measured the angles performed by the upper limbs during the entire movement. The humerus angles were automatically transformed into angular velocity (°·s−1) and angular acceleration (°·s−2). Maximum angular velocities were 27.39°·s−1 (men, right humerus) and 22.39°·s−1 (women, left humerus), both below the safe limit. Maximum accelerations were 25.32°·s−2 (men, left side) and 28.94°·s−2 (women, left side); safety values for these accelerations are not established. Monotony is a risk factor, especially for the dominant side. Future studies should evaluate risk factors simultaneously in repetitive tasks. Repetitiveness exceeds the safe limit according to the OCRA method.

Keywords

• humerus angle
• angular velocity
• angular acceleration
• repetitive movements