Functional assessment for prediction of lifting capacity.
Wheeler-DL; Graves-JE; Miller-GJ; O'Connor-P; MacMillan-M
Spine 1994 May; 19(9):1021-1026
The assessment of function for prediction of lifting capacity was investigated. Peak isometric lumbar torques were measured in 26 normal, healthy subjects aged 18 to 39 years. Isometric lumbar extension torque was measured at seven angles of trunk flexion through a 72 degree (deg) arc of motion (0, 12, 24, 36, 48, 60, and 72deg) using a lumbar extension machine. Functional lifting mechanics were recorded using two dimensional kinetic analysis. In the lifting task, subjects were asked to squat and lift a submaximal weight (2.3 kilograms (kg) for women, and 6.8kg for men), from the floor to a standing position. The video based kinetic system calculated velocities and accelerations of body segments from changes in positional locations, and estimated joint reaction forces and moments as well as muscle forces. The lumbar-5/sacral-1 (L5/S1 torque was calculated for the submaximal lift. The model developed was tested starting with weights that were 80% of predicted maximal weight, and incrementally increased until the subject could not lift the load, or it was deemed unsafe by the physical therapist. Multiple regression analysis was used to determine whether gender or body weight influenced the prediction of maximum functional lifting capacity (LOAD). Results showed that the relationship between maximum actual LOAD and maximum predicted LOAD had a slope of 1.05. Mean values were not significantly different (50.03kg and 48.5kg, respectively). The correlation coefficient was high (0.96), and total error of prediction was 10.5%. The authors conclude that the new functional assessment model accurately predicts a subject's maximum functional lifting capacity.
NIOSH-Publication; NIOSH-Grant; Musculoskeletal-system-disorders; Back-injuries; Biomechanics; Ergonomics; Job-stress; Mathematical-models; Physical-stress; Manual-lifting; Body-mechanics
Orthopaedic Surgery University of Florida Box J-246 Jhmhc Gainesville, FL 32610
University of Florida, Gainesville, Florida