Indirect biomechanics measurement on shoulder joint moments of walker-assisted gait

Abstract

The walker is a fundamental rehabilitation device and provides patient external mechanical support. A new measurement and analysis method was proposed to investigate the changes in shoulder joint moments that occur with the use of a front-wheeled walker. A strain gauge-based walker instrumentation system was developed to monitor the hand loads during walker-assisted walking and integrated with an upper extremity biomechanical model. Preliminary system data were collected for twelve subjects following informed consent. Bilateral upper extremity kinematic data were acquired with a six-camera motion analysis system. Internal joint moments at the shoulder were determined in the three clinical planes using the inverse dynamics method. Results showed that during a walker-assisted gait shoulder joint moments mainly distributed in the walker stance period. There was a noted demand on the shoulder adductor in the coronal plane with the greatest record as 0.431 Nldrm/kgldrm. An interesting ldquobare phaserdquo of mean shoulder joint moments was also found in phase angle [-240deg, 340deg] of gait cycle. Complete description of shoulder joint moments of walker-assisted gait may provide insight into walker use parameters and rehabilitative strategies.