The present research programme had three objectives. First, to develop a conceptual framework through which the psychophysical effects of music could be studied. Second, to design and validate an instrument for assessing the motivational qualities of music: The Brunel Music Inventory (BMRI). Third, to test affective and psychophysical responses to motivational and oudeterous (neutral) music conditions during a running task. The conceptual model to predict psychophysical responses to asynchronous music addressed the relationship between the constituents of music (music factors), the functionality of music (whether it is coordinated with the activity) and the mediating effect of personal factors (sociocultural upbringing and preferences) in predicting mood states, ratings of perceived exertion and arousal levels. The model was used to formulate the initial item pool for the BMRI. Exploratory factor analysis revealed a four factor solution accounting for 59.2% of the variance. The factors were labelled, Association, Popular Impact, Musicality, and Rhythm Response. The factor structure was tested using Confirmatory Factor Analysis (CFA) and exhibited acceptable fit indices. The factor structure was cross-validated using multisample CFA, demonstrating that the BMRI possessed acceptable psychometric properties. Criterion validity was also demonstrated. Next, 40 pieces of music of similar tempi were selected to represent a broad spectrum of popular music. These selections were rated using the BMRI and the tracks ranking 1-10 for their motivational qualities comprised a motivating music condition while tracks 21-30 comprised an oudeterous (neutral) condition. Thirty-four participants were exposed to each music condition plus a no-music control during submaximal treadmill running. The dependent measures were heart rate, the Profile of Mood States-C (POMS-C: Terry, Keohane, & Lane, 1996) the Feeling Scale (FS: Rejeski, 1985) and Ratings of Perceived Exertion (RPE: Borg, 1982). Results indicated that the motivational music had the most positive effect (Pillais9,25 = .72, p < .05) in terms of the FS, RPE, and the Vigour component of mood, although as expected, no differences were evidenced for heart rate. 'The differences were evidenced primarily between the motivational and control conditions with no differences between the oudeterous and control conditions. The contribution made by this research programme is that it has demonstrated how carefully selected asynchronous music can improve the exercise experience.