Abstract
This paper presents the results from two biomechanical studies that examined the effects of loading on the L5/S1 area of the lower spine. The objective of these exploratory studies was to determine whether subject, cardiovascular, and isometric and isotonic strength variables could be used to determine a worker's risk potential for back injury. The first study examined trunk velocity and torque developed in movement against a 30 lb. resistive load for two groups of people: (1) normals (no back pathology), and (2) abnormals (people with physician-diagnosed back pathology). Significant differences were found between these two groups for back torque and velocity measures. People with back pathology developed less torque and were slower in their movements. Discriminant analysis provided an 82% correct classification for normals and abnormals using velocity and torque measurements. The second investigation studied only people with back pathology and its objective was to explore the sensitivity of the testing procedure to distinguish between different degrees of back pathology. The purpose of these studies was to develop measures that could be used to screen and place people in jobs so they would not be at risk for back injury. Further work will aim at: (1) improving the discriminant function used in the first study, (2) searching for additional measures predictive of back injury risk potential, (3) reducing the resistive loads used in testing, and (4) studying non-symmetrical loading effects on the spine.
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