Assessment of shoulder loads and postures experienced by automotive seat frame assembly workers in relation to shoulder pain

The thesis documented peak and cumulative kinetic shoulder exposure experienced by seat frame assembly workers, and examined the relation between exposure and shoulder pain reported. One hundred ten employees were recruited to participate in the study. Two participants were fired before data collection began, two participants decided not to participate, and twenty-seven participants had incomplete data sets. The remaining seventy-nine participants (34 males and 45 females) filled out a questionnaire and were video-taped while performing various job tasks. 3DMatch software was used to catalogue the postures seen in the video of each task cycle, as well as hand loads and forces. These data were used by 3DMatch to calculate the cumulative and peak loads and percent time spent in neutral and non-neutral postures for each task cycle. These values were then extrapolated to an entire work shift and used for analysis.;The thesis provides peak and cumulative shoulder exposures experienced in a manufacturing industry. Despite reported literature linking cumulative and peak loading to the development of low back pain, a similar hypothesis for the shoulder was not supported by the results of this study. Differences in cumulative exposure revealed between sexes, jobs, and work shifts provide interesting avenues for further research given the absence of a relationship to shoulder pain. The lack of a clear relationship between biomechanical loading and pain suggests that pain may not be the best metric for the "response" component of the dose-response relationship.;Nearly half of the participants reported shoulder pain, however there were no significant differences between the pain/no pain groups for peak moments and forces acting on the shoulder. There was a mild correlation found between pain severity and both cumulative posterior shear and caudal shear for the left shoulder. Although there was no significant difference between sexes for report of shoulder pain, there were significant differences between sexes for peak and cumulative load variables. Females spent significantly more time in mild right shoulder flexion than males, when all jobs were combined. The day shift experienced significantly greater anterior shear than the night shift for both the right and left shoulder. Finally, there were significant correlations between some cumulative loading variables and postures used.