The chapter discusses in more detail models of intervention and the associated evidence in this area of physical activity promotion in primary care and the community. It focuses on primary health care as the setting or the means of accessing physical activity interventions, and the relatively recent move to more community settings. The chapter recognises the need for controlled research of effectiveness and cost-effectiveness, and advocates the use of pragmatic randomised controlled trials(RCTs) where usual processes are not manipulated at the expense of external validity. Quantitative research confirms that those who complete schemes have associated physical health benefits. Therefore, qualitative research is important to help in understanding what supports patients to engage and complete ERS. The two commonly-used behaviour change interventions used in primary care include Motivational Interviewing (MI) and Behaviour Change Counselling (BCC). Qualitative data also provide insight regarding the physical, mental, social, and behavioural effects of ERS.