From The Ergoweb® Learning Center

Upper Extremity Symptoms/Clinical Findings Occur in Proportion to Ergonomic Stressor Index

Exposure to combined high ergonomic stressors leads to a greater risk of developing upper extremity symptoms, says a new study. In the study of 790 automobile manufacturing workers, those exposed to the highest ergonomic stressors had three times the chance of developing an upper extremity condition compared to workers exposed to the least ergonomic stressors.

Researchers collected baseline questionnaire data of each subject’s job including exposure to non-neutral postures, work pace, vibration, manual forces to handle tools and parts, and mechanical pressure concentrations from handheld tools.  Each subject’s responses were added to create an index of overall upper extremity ergonomic exposures.  The range of all subjects’ exposure indexes were used to create categories of very low, low, moderate and high exposure levels.  Subjects also reported upper extremity symptoms and were examined for upper extremity clinical findings at baseline.

After one year, the subjects were interviewed again regarding ergonomic stressors and evaluated for upper extremity symptoms and clinical findings.

Sixty-eight new symptom cases (14 percent) and 62 new clinical finding cases (12 percent) were found.  While controlling for confounders, the incidence of new cases increased with exposure level intensity to create an exposure/response trend.  Also, subjects who switched to jobs with a high exposure index had greater incidence of new symptoms/clinical findings while subjects who switched to very low exposure index jobs had less incidence.


Punnett L, Gold J, Katz JN, Gore R, and Wegman DH. “Ergonomic Stressors and Upper Extremity Musculoskeletal Disorders in Automobile Manufacturing: A One Year Follow Up Study.” Occupational and Environmental Medicine 61:668-674, 2004.


This article originally appeared in The Ergonomics Report™ on 2004-11-02.