2 | 55 A new life stage, a new sport activity? Similar to children leaving home, a competitive club sport is relatively well suited to life after retirement, as retirement increases leisure time availability and social resources diminish. Once again, note that we must obviously take age into consideration when we test this expectation, as people mostly retire at older ages when sport participation is less common. Our hypothesis here is the following: Retirement increases the odds of starting a competitive club sport, compared to starting a sport in some other organisational form. METHODS Data To answer the research questions, we used individual life course data from the Sporters Monitor 2010 (Van den Dool, 2010). The reporting on this Sporters Monitor was done by the Mulier Institute, at the request of the NOC*NSF. The Mulier Institute conducts fundamental and practice-focused research on sport and monitors developments within the Dutch sport sector. The Dutch ConsumerJury Panel of GfK, the fourth largest market research organisation in the world, was used as the sampling frame for the SportersMonitor 2010. This panel is representative of the Dutch population aged 15 and older with respect to the characteristics age, sex, region of residence and educational level. In total, 4031 persons completed the questionnaire during the fieldwork period, for a net response rate of 67.2%. The Sporters Monitor 2010 was administered via a computer-assisted web interviewing (CAWI) questionnaire. For the current study, we analysed the sport careers of persons aged 18 years and older. Of the 3540 adult respondents, 2707 (76.5%) were asked retrospective questions about their sport activity. This concerned persons who during their lifetime had participated in at least one sport regularly (i.e., at least once every 14 days), or did so intensively (i.e., at least four days per year for a large part of the day) in a specific period of the year (e.g., seasonal sports like sailing in the summertime, of skiing in the winter). We removed from the dataset the 833 adult respondents who reported