In collaboration with Dr. Jack Callaghan, Canada Research Chair in Spine Biomechanics and Injury Prevention at the University of Waterloo and Dr. Kayla Fewster, Assistant Professor in School of Kinesiology at the University of British Columbia, Drs. Chad Gooyers and Rob Parkinson (Senior Biomechanical Experts at 30 Forensic Engineering) have recently published one of the first studies to document the peak lumbar spine forces and motion experienced by human volunteers during simulated low speed rear-end collisions.
Twelve males and twelve females between the ages of 18-35, free from any prior low back or neck injury spine injury, experienced simulated collisions conducted on a custom-built collision simulation sled (Figure 1). The participants were exposed to rear-end collision severities of approximately 8 km/h, consistent with the vehicle speeds observed in parking lot collisions and bumper-to-bumper traffic, which is below published thresholds associated with soft tissue neck injury. Prior to any testing, ethics approval for research involving human participants was obtained from the Office for Research Ethics at the University of Waterloo.
Figure 1: Photograph of the custom-built collision simulation sled. Participants were seated and belted in the automotive seat. The seat assembly was then released from the top of the ramp and rolled back to impact 4 springs.
A motion capture system was used to measure the position of the thorax and pelvis, while seat back forces were estimated using a pressure measurement system installed on the seat back and the seat pan. The data gathered was incorporated into a 3D biomechanical model to estimate the forces occurring within the lumbar spine.
Consistent with prior research using cadavers and crash test dummies, we found that the peak spine forces were low and were well below the forces that are considered safe for repeated lifting tasks in the workplace (Figure 2) and were insufficient to cause injury to the lumbar spine.
Figure 2: Average peak compression and shear reaction force across all conditions in comparison to current threshold limit values for occupational lifting. SD bars are displayed. NIOSH indicates National Institute of Occupational Safety and Health.
Citation: Fewster, K.M., Zehr, J.D., Gooyers, C.E., Parkinson, R.J., & Callaghan, J.P. (2022). Characterizing lumbar spine kinematics during simulated low-speed rear impact collisions. Journal of Applied Biomechanics, 38: 155-163.
Full-text paper can be accessed here.
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