Design and Implementation of a Smartphone Application for Estimating Foot Clearance during Walking

Maximum Foot Clearance (MaxFC) is the maximal foot height during the swing phase relative to the ground, and is a gait variable that is highly associated with tripping and falling. An iPhone mobile application is designed to analyze the MaxFC in real time using the iPhone’s built-in accelerometer and gyroscope to collect data when the phone is attached to the shank of the leg. Our method is based on double integration and drift cancellation of foot acceleration signals. An optical motion capture system was used as gold standard, and the results show the mean error over all strides is less than 10.3%. The findings illustrate the feasibility of using an iPhone application to estimate MaxFC. The application is designed and implemented to display the foot clearance results conveniently. A user study was conducted and feedbacks indicate that this application can be suitable to self-monitor risk of falls to prevent falling.