An Evaluation Strategy for the Symmetry and Consistency of Lower Limb Segments During Upper Limb Loading

Weight-bearing is one of the common daily behaviors. Evaluating the gait symmetry during weight-bearing is helpful to reveal the health status and pathological characteristics of the human body. The purpose of this paper is to propose and verify a regression angle offset model (RAOM). Symmetry classification rules were established by using the offset angles of different weight-bearing patterns, and the movement consistency was measured by the range of offset in multiple experiments. Eight healthy subjects performed flat walking experiments under five weight-bearing patterns, and the gait data on the left and right sides of the shanks and thighs were modeled. The results showed that 87.5% of subjects had a left-leaning gait on the shanks, whereas 75% had a right-leaning gait on the thighs during normal walking. The movement consistency of the thighs amounts to 90%, 12.5% higher than that of the shanks. When walking with a weight held in the right hand or in the left hand, the symmetry of the thighs increased by 25% and 12.5%, respectively, compared with the shanks. The overall evaluation results of symmetry showed that 87.5% of subjects had a constant or better symmetry on the thighs relative to the shanks, and symmetry levels on the thighs improved 12.5% relative to the shanks. The evaluation strategy for symmetry and consistency based on multiple sensors can analyze subtle differences in complete lower limb movement, which can be applied to wearable assistive device control or biofeedback gait retraining.