Abstract: A system is disclosed for selecting and integrating music received from a user's personal music library into an exercise routine. The system includes a music analyzer software module that characterizes rhythmic qualities of each song in the music library, creating a rhythmically quantified collection of the user's music which serves as one input to a song selection module. Other inputs to the selection module include target workout parameters and user defined data that include the user's physical metrics and the user's preferences for song selection and repetition. Real time data associated with the user's physical activity can also be supplied to the selection module, which associates particular songs with the user's physical activity. The song selection module supplies the selected songs in a sequential fashion to a personal music device worn by the user while the user is engaged in a structured type of physical exertion.