Embodiments of the disclosed technology are directed to classifying motion data collected by wearable sensors. Motion data collected by a first wearable motion sensor and a second wearable motion sensor during the performance of an activity can be obtained. The motion data from the first wearable motion sensor can include data associated with one or more first motion primitives and the second motion data collected by the second wearable motion sensor can include data associated with one or more second motion primitives. The first motion data and the second motion data can be synchronized based at least in part on time stamp information. Data associated with a signature motion classification associated with the activity can be determined based at least in part on the one or more first motion primitives and the one or more second motion primitives.