Basic study on ages at which Japanese athletes begin playing sports

The question “At what stage in their physical growth and development should youths start playing a sport?” is of considerable interest to those involved in the fields of sports, education, medicine, and health. This is because the topic is expected to provide significant information not only on when youths should start playing a sport so that it contributes to their healthy physical growth and development but also on strategies for cultivating excellent sports players, how to prevent sports‒related physical damage and disease, and how physical education should be organized. In order to benefit from such information, we need reliable statistics on the ages for starting a sport. However, the current situation is such that reliable information on this issue is not available anywhere in the world. We conducted a literature search across various fields on “ages at which athletes start sports,” but the search did not reveal any documents containing statistical information relevant to this topic. This brief report was prepared to address this lack of information. In an earlier study, Osawa et al. (1994) collected longitudinal data on the development of athletes for the purpose of making comparisons between male and female athletes across various sports. In that process, we investigated the “ages at which athletes start sports.” This study was limited to the collection of data from athletes confirmed to have been playing sports from a young age up to the point of investigation. The reason for this was a reflection of the fact that many investigations on this topic record the age at which target athletes began a sport and then go on to discuss those cases without confirming whether the athletes in question had continued to play the sport thereafter. For example, data in this study indicating age 10 as the start of playing a sport does not include cases wherein a youth begins the sport at age 10 but stops it at 11. In contrast to longitudinal data, cross‒sectional data showing the frequency of sports played at a certain point in time is not able to provide a substantial answer to the question of at what point in their physical developmental process did a particular group begin a sport. The data in this study on the ages at which youths started a sport enables longitudinal observation while avoiding the inclusion of such incomplete information mentioned above. This study focused on the following three points: 1. At which ages do Japanese athletes start playing a spor