The purpose of the present study was to identify the characteristics of music used to accompany physical exercise and investigate the effects of such music using a qualitative approach. This work underpins the further development of a theoretical structure that is still relatively new. Semi-structured interviews were conducted with a sample of exercise participants (N = 13), seven males and six females, all with at least two years' experience of exercising to music. An inductive content analysis of the interview data was undertaken and results contrasted with the conceptual model developed by Karageorghis et al. (1999) which describes the effects of musical and cultural factors with reference to psychophysical outcomes. The findings demonstrated the importance of musical (e.g. rhythm, lyrics, bass), contextual (e.g. time of day) and individual factors (e.g. background, personality) in determining both short-term (e.g. mood, imagery) and long-term (e.g. heightened work-rate, endurance) outcomes. The findings point towards a more expansive conceptual framework. In particular, facets of the response to music such as flow state, cognitive responses, rhythm response and anticipation are discussed. Music perceived to be motivating could lead to increases in exercise intensity and endurance during performance of self-regulated tasks. These findings have implications for the use of music in physical education settings. (Contains 1 table and 1 figure.)