The aim of this thesis is to produce a substantive grounded theory of junior-to-senior transition and as a result of this work, to provide knowledge and guidance for coaches, sport psychologists and other personnel supporting young aspirant athletes. Underpinned by a social constructionist philosophy, the research programme was designed to capture and interpret the social world of the participants and to interpret the perceptions derived from their own lived experience of the transition. The thesis consists of three studies which, in a concatenated programme of research, are predicated one upon another. In order that understanding in social research can be advanced, the development of theory requires several rounds of fieldwork, analysis an...