Energetics of ambulation with spring-loaded crutches

Habitual users of underarm crutches may suffer severe shoulder and wrist pain. Our aim is to investigate the effect of using spring-loaded crutches on mechanical efficiency by comparing its performance with standard crutches through a biomechanical approach. In our experiments, seven male subjects were instructed to walk around a track on crutches for 5 minutes under 4 controlled conditions. The externally-loaded and segmental work involved with the motions was computed based on ground reaction forces and centre of motion trajectories. Simultaneously, portable gas analysis machinery was used to collect the metabolic parameters of subjects to work out mechanical efficiency, the ratio of mechanical to metabolic work. It was found that the mechanical efficiency was significantly higher when subjects walked with spring-loaded crutches than when they walked with standard crutches.