Modeling and simulating lifting task of below-knee amputees

Abstract

Lifting is a common activity to below-knee amputees (BKA) in occupational and living occasions. Appropriate lifting posture is crucial to physical safety and health to those BKAs. Often healthy parts of BKAs might be hurt due to extra and asymmetric force exertion compensating for deficiency of disabled body parts. To prevent further hurt, a validated biomechanical model describing lifting is essential to analyze lifting behavior of those handicapped. In this study, twelve BKAs were recruited to lift 45 N weights from the floor. Subjects are asked to lift three levels of weights (0 N, 30 N, 60 N) by two postures: squat lifting and stoop lifting. Twelve non-BKAs were recruited as comparison group to study the variance caused by disability. Calculated forces based on Anybody were compared with EMG signals of body parts on spine and thigh. A framework of three-level constraints models were applied to adjust the difference between calculated forces and EMGs and the results validate the model.