The app will make use of the iPhone 5s’ co-processor and CoreMotion APIs in iOS 7, essentially allowing the app to track your movements more reliably and accurately while collecting data in the background. Best of all, this can be done even when the phone is asleep and will help contribute to more efficient battery use. The data collected by the phone will then be converted into NikeFuel, which is basically a metric used by Nike to gauge how active you are which can also be used to compare against friends or other Nike+ Move users. This is similar to how the Nike FuelBand works so if you don’t want to spend extra money on the FuelBand, your iPhone 5s should do the trick.