Evaluation of Working Postures and Musculoskeletal Disorders Among Color Mixing Workers in a Plastic Manufacturing Facility

Abstract

This study aimed to evaluate the ergonomic risks of color mixing workers in a plastic injection molding factory using the Rapid Entire Body Assessment (REBA) technique, and to analyze the relationship between working postures and musculoskeletal disorders (MSDs). The sample consisted of four male workers with a mean age of 35 ± 7.16 years, a mean body weight of 59.5 ± 9 kilograms, and an average height of 165.75 ± 11.79 centimeters. The survey revealed that 75% of workers experienced pain in the neck, lower back, and knees in the past six months, and 50% reported symptoms in the lower back and knees in the last seven days. The REBA assessment showed that posture 1 (lifting plastic pellets) posed the highest ergonomic risk (55%), primarily due to neck tilting, arm elevation, and force exertion exceeding 22 pounds. Posture 3 (removing pellets from the machine) had a high risk of 25%, while posture 4 (bagging plastic pellets) posed a moderate risk (20%). Pearson's correlation analysis revealed a strong positive correlation between posture 1 and knee disorders (r = 0.962, p = 0.038), and a strong negative correlation between posture 3 and wrist/hand disorders (r = -0.977, p = 0.023). The study concludes that workers are at significant risk of MSDs due to repetitive tasks and excessive force, and recommends improvements such as lifting aids and ergonomically designed workstations to reduce health risks.