Analysis and measurement of neck loads.
Moroney-SP; Schultz-AB; Miller-JA
J Orthop Res 1988 Sep; 6(5):713-720
A biomechanical model developed to determine the loads imposed on the structures of the neck during the performance of various physical tasks was described. Fourteen healthy male and female adult subjects participated in the study. Each participant performed 30 quasistatic tasks stressing the neck musculature. Subject were seated with the trunk restrained and were fitted with electrodes mounted at the C4 level of the neck and a helmet equipped with attachments to permit the application of external loads. Series of tasks were performed that required the subject to resist the flexion moment created by an anteriorly directed force or to resist applied moments by twisting the neck to one side. A biomechanical model based upon 14 bilateral pairs of muscle equivalents crossing the C4 level was used to evaluate the contraction forces in the neck muscles and the compression and shear loads imposed upon the cervical spine during task performance. The mean voluntary neck strengths produced in the 14 subjects ranged from 3.6 to 25.9 newton meters depending upon the task, and the largest applied moment occurred during attempted extension. The mean neck strengths for the females were approximately 60 to 90 percent of those for the males for all tasks performed. The mean predicted motion segment reactions for the maximum voluntary exertions ranged from 0 to 125 newtons (N) for lateral shear, from - 2 to 135N for anteroposterior shear, and from 122 to 1,164N for compression. The largest lateral shear occurred during lateral bending, and the largest values for anteroposterior shear and compression were recorded for extension. The correlation coefficients between the predicted muscle forces and the myoelectric signals for the 30 tasks ranged from 0.29 to 0.85.
NIOSH-Publication; NIOSH-Grant; Mechanical-tests; Skeletal-stress; Simulation-methods; Skeletal-movement; Biomechanics; Analytical-models; Humans; Sex-factors; Spinal-cord; Musculoskeletal-system-disorders
Mechanical Engineering University of Michigan Dept of Mech. Engr Ann Arbor, Mich 48109
Journal of Orthopaedic Research
University of Michigan at Ann Arbor, Ann Arbor, Michigan