Biomechanics in crutch assisted walking

Different diseases may require patients to use crutches in their daily life. While upper limbs fatigue is limited when a temporary impairment is considered, it may become an important issue when considering permanent impairments such as those due to stroke or multiple sclerosis. These situations are rather common and important today for the quality of life of persons with chronic locomotion impairments[1]. On the other hand, walking is a fundamental human activity and if impaired, people prioritize it as a goal of treatment. In Europe walking aids, such as crutches, are the most prescribed tools in case of central nervous system lesions [2,3]. Moreover active exoskeletons for spinal cord injured patients are commonly crutch assisted. In such cases, in which upper limbs must be preserved, specific training in crutch use is mandatory. On this basis, a pair of instrumented crutches was developed to measure both crutch load and orientation [4], and they were integrated with an optoelectronic motion capture system, an anthropometric volume scanner, and a biomechanical model, in the Bullet project [5]. Bullet biomechanical model, process the measurement data to obtain limbs loads with special attention to torques at shoulders [6]. The project focus is related to exoskeletons assisted walking but the approach is general and, in this paper, some preliminary results are presented for healthy subjects walking with crutches without exoskeletons. The main goal is to investigate differences in crutchassisted gait following the three points strategy - or parallel crutch use – and the two points strategy – or alternate crutch movement. Therefore, some results regarding crutch kinematics and loads for the two strategies are here presented.