Differences in whole-body angular momentum between below-knee amputees and non-amputees across walking speeds

• Published in: Journal of biomechanics 2011-02, Vol.44 (3), p.379-385
• Main Authors: Silverman, A.K, Neptune, R.R
• Format: Article
• Language: English
• Subjects: Amputation; Amputees; Angular momentum; Biological and medical sciences; Biomechanical Phenomena; Biomechanics; Biomechanics. Biorheology; Braking; Control; Falling; Fundamental and applied biological sciences. Psychology; Gait; Gait - physiology; Ground reaction forces; Hip joint; Humans; Knee; Knee - physiology; Knee Joint - physiology; Locomotion; Medical sciences; Middle Aged; Orthopedic surgery; Physical Medicine and Rehabilitation; Planes; Prostheses; Risk; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Tissues, organs and organisms biophysics; Transtibial amputee; Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports; Walking; Walking - physiology
• ISSN: 0021-9290; 1873-2380
• DOI: 10.1016/j.jbiomech.2010.10.027

Abstract Unilateral, below-knee amputees have an increased risk of falling compared to non-amputees. The regulation of whole-body angular momentum is important for preventing falls, but little is known about how amputees regulate angular momentum during walking. This study analyzed three-dimensional, whole-body angular momentum at four walking speeds in 12 amputees and 10 non-amputees. The range of angular momentum in all planes significantly decreased with increasing walking speed for both groups. However, the range of frontal-plane angular momentum was greater in amputees compared to non-amputees at the first three walking speeds. This range was correlated with a reduced second vertical ground reaction force peak in both the intact and residual legs. In the sagittal plane, the amputee range of angular momentum in the first half of the residual leg gait cycle was significantly larger than in the non-amputees at the three highest speeds. In the second half of the gait cycle, the range of sagittal-plane angular momentum was significantly smaller in amputees compared to the non-amputees at all speeds. Correlation analyses suggested that the greater range of angular momentum in the first half of the amputee gait cycle is associated with reduced residual leg braking and that the smaller range of angular momentum in the second half of the gait cycle is associated with reduced residual leg propulsion. Thus, reducing residual leg braking appears to be a compensatory mechanism to help regulate sagittal-plane angular momentum over the gait cycle, but may lead to an increased risk of falling.