Pendular model of paraplegic swing-through crutch ambulation.

Kinematics of swing-through crutch ambulation for an individual with complete T11-T12 spinal cord injury was examined and quantitative aspects of the body-swing phase used to formulate and evaluate a 3-link pendular model. Model simulation parallels measured kinematics when shoulder motion is forced to follow the measured motion while hips and crutch tips are free pivots. Shoulder control contributes to increased ground clearance, influences timing and stride length, and gives flowing gait. Results indicate that mechanical work requirements during the body-swing phase are low. Metabolic energy demands exceed mechanical work requirements, due particularly to support of the body by the arms and shoulders. Exploiting low mechanical work requirements of the body-swing phase might be achieved through alternative mechanisms to assist ground clearance and to stabilize the wrists, arms, and shoulders while weight bearing.