In the current obesogenic society dominated by sedentary lifestyles the government has launched various campaigns that aim to facilitate a more active society. Moreover, the benefits of regular physical activity, such as the regulation of body weight, improved insulin sensitivity, and reductions in hypertension have led to the inclusion of structured exercise interventions within various rehabilitation settings to help effective management of chronic health conditions. This chapter focuses on the importance of self-determined motivation to enhance physical activity uptake and adherence, using stealth approaches as an example of how this can be applied. A large body of research acknowledges the importance of being intrinsically motivated to sustain physical activity changes. However, traditional programmes, such as exercise referral schemes, often seem to depend on participant's extrinsic motivation, such as advice from the health professional, so sustainable behaviour change may be unlikely.