A Biomechanical Analysis of the iWALK Hands-Free Crutch on Upper Leg Musculature: Modeling Muscle Activation in Above-the-Knee Amputees

The iWALK hands-free single leg crutch (HFSC) is a mobility device designed as a substitute for traditional crutches when a patient has a below-the-knee injury. Its purpose is to remove weight bearing from the lower leg and increase the patient's mobility and comfortability in comparison to traditional crutches. It can also be used to explore possible differences in muscle activation between legs providing insight into possible muscle imbalances of above-the-knee amputees. While the HFSC has slowly been implemented as an alternative to traditional crutches, there has been minimal research done to determine the impacts on muscle activation with use of this new style of crutch. The purpose of this study was to explore muscle activation differences between use of the HFSC and without (normal walking) across a 20 meter distance. By comparing these two conditions, we can model the gait of an above-the-knee amputee, therefore quantifying the potential shift in muscle activation in the rectus femoris and biceps femoris using surface electromyography sensors (EMGs). Our hypothesis is that as a person walks with the HFSC, their muscle activation increases to adjust to using the device due to the loss of the kinetic chain that is the entire leg, similarly to an above-the-knee amputee.