28 | Chapter 1 respondents, from within-developments in respondent’s life courses. The analyses indicate that respondents who leave full-time education, begin to work, enter and/or formalise a relationship, and become a parent, participate less frequently in sport than those who do not (between-person differences). Moreover, the sport frequency decreases after experiencing these events (within-person changes). Additionally, all events except beginning to work have a negative impact on the number of sports practised. This is reflected in both between-person differences and within-person changes in the number of sports practised after leaving full-time education, entering an intimate relationship, and becoming a parent. Formalising a relationship through cohabitation or marriage only results in a between-person difference. Further, those who enter an intimate relationship are more likely to switch from a “heavy” club-sport setting to a “lighter”, more individualised setting and to stop practising sport altogether, compared to those who stay single. Those who leave full-time education and start working are more likely to continue sport in a club setting, compared to those who continue education and do not start working. Career, family and sport participation: a simultaneous exhibition? A study of narratives on the impact of major life events during the transition to adulthood (chapter 5) The results from the quantitative studies (chapters 2, 3 and 4) show that major life events marking the transition to adulthood affect sport participation. However, insights regarding the explanatory mechanisms behind the effects are given only by assumption and not investigated directly. Therefore, in this last empirical chapter I aim to open this “black box” with narrative data in response to the question: why and how do people change their sport participation during the transition to adulthood, specifically when major life events occur? I focus on major life events that mark this transition within two life domains: the professional career (e.g., entering high/secondary school and higher education, graduation or leaving fulltime education, starting a job) and the family domain (e.g., engaging in an intimate relationship, cohabitation, marriage, becoming a parent: birth, 1st child, 2nd child, etc.). The rationale for this particular focus is that, based on the previous empirical chapters, I identify the transition to adulthood as a threat to sustainable sport participation, and these life domains as being important areas of personal development in general and