Use of accelerometers as an ergonomic assessment method for arm acceleration - a large-scale field trial

Ergonomists need easy-to-use, quantitative job evaluation methods to assess risk factors for upper extremity work-related musculoskeletal disorders in field-based epidemiology studies. One device that may provide an objective measure of exposure to arm acceleration is a wrist-worn accelerometer or a ctivity monitor. A field trial was conducted to evaluate the performance of a single-axis accelerometer using an industrial population (n = 158) known to have diverse upper limb motion characteristics. The second phase of the field trial involved an examination of the relationship between more tradi tional observation-based ergonomic exposure measures and the monitor output among a group of assembly-line production employees (n = 48) performing wo rk tasks with highly stereotypic upper limb motion patterns. As expected, t he linear acceleration data obtained from the activity monitor showed stati stically significant differences between three occupational groups known ob servationally to have different upper limb motion requirements. Among the a ssembly-line production employees who performed different short-cycle assem bly work tasks, statistically significant differences were also observed. S everal observation-based ergonomic exposure measures were found to explain differences in the acceleration measure among the production employees who performed different jobs: hand and arm motion speed, use of the hand as a h ammer, and, negatively, resisting forearm rotation from the torque of a pow er tool. The activity monitors were found to be easy to use and non-intrusi ve, and to be able to distinguish arm acceleration among groups with divers e upper limb motion characteristics as well as between different assembly j ob tasks where arm monitors were performed repeatedly at a fixed rate.