Systems and methods are disclosed for categorizing a device use case for on foot motion with a portable device. Motion sensor data corresponding to motion of the portable device may be obtained, such as from a sensor assembly of the device. The motions sensor data is processed. Further, a use case characteristic may be determined from the processed and/or raw motion sensor data, an effective frequency may be determined from the processed and/or raw motion sensor data and/or an Eigen use case may be determined. The device use case may then be classified using the processed and/or raw motion sensor data and at least one of the use case characteristic, the effective frequency and the Eigen use case.