Apparatuses and methods are disclosed for identifying with a single, small, intelligent activity monitor a particular type of activity from among a plurality of different activities. The monitor may include a multi-axis accelerometer and microcontroller configured to combine and process accelerometer data so as to generate features representative of an activity. The features may be processed to identify a particular activity (e.g., running, biking, swimming) from among a plurality of different activities that may include activities not performed by a human subject. An intelligent activity monitor may be configured to operate as a versatile sensor, or to operate in combination with a versatile sensor, to further receive and process physiological data and compute a fitness metric for a subject.
