Characterizing Lumbar Spine Kinematics and Kinetics During Simulated Low-Speed Rear Impact Collisions.

Abstract

Recent work has demonstrated that low back pain is a common complaint following low-speed collisions. Despite frequent pain reporting, no studies involving human volunteers have been completed to examine the exposures in the lumbar spine during low-speed rear impact collisions. Twenty-four participants were recruited and a custom-built crash sled simulated rear impact collisions, with a change in velocity of 8km/h. Randomized collisions were completed with and without lumbar support. Inverse dynamics analyses were conducted, and outputs were used to generate estimates of peak L4/L5 joint compression and shear. Average (SD) peak L4/L5 compression and shear reaction forces were not significantly different without lumbar support (compression = 498.22N [178.0N]; shear = 302.2N [98.5N]) compared to with lumbar support (compression = 484.5N [151.1N]; shear = 291.3N [176.8N]). Lumbar flexion angle at the time of peak shear was 36° (12°) without and 33° (11°) with lumbar support. Overall, the estimated reaction forces were 14% and 30% of existing National Institute of Occupational Safety and Health occupational exposure limits for compression and shear during repeated lifting, respectively. Findings also demonstrate that, during a laboratory collision simulation, lumbar support does not significantly influence the total estimated L4/L5 joint reaction force.