Dynamic and Energetic Analysis of Impacts in Crutch Locomotion

Crutch walking is a widespread type of gait among elderly and injured people. The main problem of crutch locomotion is its high energy consumption which is between two and three times that of normal walking in terms of metabolic cost [1]. Furthermore, it is highly demanding for the upper-body muscles, which are not suited for such efforts. Despite these inconveniences, the psychological importance for the subjects of being able to stand and walk on their own makes this type of locomotion very common. The swing-through crutch gait consists of four phases: crutch-stance phase, heel strike, footstance phase and crutch strike. In this work, we pay particular attention on the crutch strike that occurs at the end of foot-stance. This has been reported to be an important cause of energy loss during motion [2]. A four-segmental planar model of the human body is used to analyze various dynamic aspects of the crutch impact, e.g., kinetic energy redistribution, velocity change and the magnitude of contact impulses. The model and coordinates used are shown in Fig. 1, body segment parameters are based on anthropometric data.