Development of a method for quantifying biomechanical risk factors associated with manual and mechanically assisted patient handling

"This project developed methods for estimating biomechanical risk associated with patient handling activities, and trialed these approaches for objectively comparing use of a slider sheet (manual) with use of an overhead lift (mechanically assisted) for repositioning patients in bed. Two biomechanical approaches were developed, using either measurement of forces beneath the caregiver's feet (ground reaction forces - force platform method) or forces at the caregiver's hands (hand reaction forces - force matching method) as input variables to a linked segment model of the human body. The dynamic position of each body segment was captured using an eight-camera digital motion analysis system. Both approaches provide an estimate of compressive and shear loading of the lumbar spine, which are indicators of injury risk to the back. Under the conditions of this project, the use of hand reaction forces underestimated peak compressive loads at the spine by 6% to 32%; however, this approach also provided an indication of injury risk to the shoulder by estimating shoulder moments. In addition to peak tissue loads, the cumulative load was estimated by integrating the load magnitude by the duration of the activity. Larger cumulative loads have been associated with increased risk for back injury"--Executive summary.