Effects of Shoulder, Low Back, or Knee Strength Degradation on Motion Control Strategies and Injury Risk during Manual Materials Handling

摘要

The objective of this research grant was to systematically investigate if and how dynamic (isokinetic) muscular strengths in three major body joints (the shoulder, low back, and knee) affect injury risk associated with manual materials-handling. Our long-term goal is to develop quantitative tools and guidelines that integrate the measurable strength and movement information for the recognition, prediction, and prevention of occupational musculoskeletal injuries. We first evaluated the dynamic (isokinetic) strengths of human subjects, and established a sizable dynamic strength databases with various stratification schemes; we designed and conducted a unique simulated manual materials-handling experiment to investigate subjects' batch-assorting strategy and lifting kinematics under various task conditions created by varying load-handled, body symmetry, and knowledge of strength. We identified a relationship between dynamic isokinetic strength and the batch-assorting strategy. This was done to initiate a manual materials-handling task and an effect of self-knowledge of the strength on that relationship. We also discovered that relative strength between the back and knees can differentiate and predict lifting biomechanics: persons with back strength greater than their total knee strength tended to use a back lift strategy, and vice versa.