Impacts of frequency and posture on body mass index in manual handling tasks

Abstract

Workspace design plays an important role in ensuring workers' safety and welfare. The issue is more pressing in the manufacturing industry, where many workers must remain in a standing position, assume awkward postures, and perform repetitive tasks for extended periods of time. In this research, an electromyographic measurement technique was used to measure activity of four back muscles: the trapezius p. descendens, the deltoideus p. scapularis, the infraspinatus, and the latissimus dorsi. The results showed a statistically significant (p < 0.05) impact of left versus right side of the body, the degree of rotation to the right side of the body (0, 30, and 60 degrees rotation to the mid-sagittal plane), body mass index level (normal weight [<25 kg/m2] vs. overweight [≥25 kg/m2]), and tasks (high vs. low frequency). In this study, the role that workers and workspace variation play is clearly associated with an increase in the amplitude of electromyography at the targeted back muscles. © 2009 Wiley Periodicals, Inc.