Force-Exertion Postures with External Bracing in Industrial Tasks: Data from an Automotive Assembly Plant

During one-handed tasks, individuals will often support their body mass using the contralateral hand or other body region. It is hypothesized that bracing postures are adopted to reduce and/or change the tasks demands, allowing the individual to assume a more optimal posture or reduce spinal loading. Accurate representation of such task postures is essential for accurate assessment of worker capability (Chaffin & Erig, 1991). It is especially critical given that the risk of injury is greatly increased when job strength requirements exceed worker capabilities (Chaffin, et al., 1978). Biomechanical analyses of supported or externally braced tasks are difficult to analyze because the upper body support is statically indeterminate. As an initial step to understanding bracing behaviors, a plant survey was conducted to investigate the prevalence of such bracing postures adopted during automotive assembly tasks. Video data from 436 occurrences of externally braced task postures from 20 automotive assembly operations were analyzed. Categorical analysis identified postural strategies associated with externally supported exertion tasks.