This thesis began with practitioner observations in a specialist personal training practice, where anecdotal themes were noted from middle-aged clients (45-65 years old). Sedentary, exercise-averse individuals reported poor experiences of physical education in secondary school, whereas active clients gave a different narrative. These themes suggested differing life course trajectories that could result in ‘corporeal dissociation’ (CD), a term, defined here to describe a state of physical detachment that might result in adult inactivity. ‘Lives lived’ were investigated through a lifecourse theoretical perspective, within a pragmatic paradigm. Methodological Bricolage employed both qualitative and quantitative multi-methods to look at the research questions from differing perspectives. In Study 1, 10 practitioners were interviewed qualitatively to see if the original observations were replicated in other practices within the same geographical area. Data was analysed using content and emergent thematic analysis and it was found to be so. In Study 2, 800 middle-aged men and women across England completed a quantitative online survey that covered 63 experiences, grouped thematically, between the ages of 11-16: ‘home’, ‘about me’, ‘school’, ‘friends and leisure activities’. Data was statistically analysed using Principal Component Analysis followed by ANOVA and 16 significant dispositions and experiences centred around PE emerged as signifiers of corporeal dissociation in middle age. Study 3 took a sample of 8 men and 8 women from Study 2. It used narrative inquiry and established lifecourse themes of activity and inactivity that link adolescence and middle-age, with the individual’s relationship with their PE teacher being the biggest signifier and influence on later physical activity. Results show that corporeal dissociation can be found in practice and its origins in PE experience identified. Tentative life path signifiers have been determined and have been mapped between school and middle age. The outcome of the study is an understanding and definition of corporeal dissociation and a scalable tool for the practitioner to identify corporeal dissociation in new clients to help aid initial exercise adherence by prescribing suitable exercise programming