The energy expenditure monitoring system of trail hiking using smart phones

In this study, a mobile-based system for monitoringenergy expenditure of the level and gradient walking was developed. A smart phone embedded with GPS and motion detectorswas adopted to detect the locations and altitudes of trail paths for calculating energy expenditure in real-time manner. Unlike other simple applications which cannot be fittedin outdoor environments, the system we designed considers various conditions reported inprevious investigations bycombiningthe advantages of smart phones and features of different terrains.Thelocations and altitudes ofa trailwere digitized and overlapped on the Google map for trail guiding. The recorded information was then used to calculate energy expenditure for real-time display during hiking.The energy expenditure was calculated based onheight, weight, and gender of the user. In order to reduce the computational time, several constants and features were calculated in advance and store in the mobile memory for real-time application. Future studies will focus on improving the accuracy of detectinga location and altitude, especially in the mountain areas.