Descriptive statistics.

Background
Participation in youth sports is a major determinant of current and future health, yet participation rates are declining. It is of great importance to examine the factors that potentially influence adolescents’ levels of participation in organised sports.
Aim
First, we examined change in participation over two years from the start of secondary education. Second, we examined whether a combination of factors (i.e. motives, barriers, perceived competence, encouragement and motor skills) based on the Youth Physical Activity Promotion model was associated with participation after one year. Third, we examined whether the associations between each of the factors and participation in organised sports changed over time.
Methods
Data were collected on three occasions between October 2020 and November 2022 using questionnaires, motor skill test items and anthropometric measurements. We analysed data from 204 Dutch adolescents (11 to 14 years) using dependent t tests, Cochran’s Q test and multilevel linear fixed effects regression models.
Results
First, participation in organised sports was stable during the first years of secondary education. Second, adolescents who reported higher motives, higher perceptions of competence and more encouragement spent more time in organised sports one year later. Barriers and motor skills did not predict participation. Third, relationships of each of the six factors with participation remained stable over time.
Conclusion
Although participation in organised sports is often considered to decline during the first years of secondary education, it can be stable for a significant portion of the population. Motives, perceived competence, and encouragement seem crucial to stimulate adolescents’ participation in organised sports.

研究背景
青少年体育参与是当前与未来健康的重要决定因素，然而当前有组织体育活动（organised sports）参与率正呈下降趋势。因此，探究潜在影响青少年参与该类活动水平的相关因素，具有重要的研究价值。

研究目的
其一，探究中等教育起始阶段后两年内青少年体育参与情况的变化趋势；其二，基于青少年身体活动促进模型（Youth Physical Activity Promotion model），检验动机、参与障碍、感知运动能力、外界鼓励与运动技能这一系列因素的组合，是否与一年后的有组织体育活动参与情况存在关联；其三，分析各因素与有组织体育活动参与之间的关联是否随时间推移发生变化。

研究方法
本研究于2020年10月至2022年11月期间，通过问卷调研、运动技能测试项目与人体测量指标采集，分三次完成数据收集。最终纳入204名年龄在11至14岁的荷兰青少年作为研究对象，并采用配对t检验、科克伦Q检验（Cochran’s Q test）以及多层线性固定效应回归模型对数据进行分析。

研究结果
其一，中等教育初期阶段的有组织体育活动参与情况整体保持稳定；其二，报告更高运动动机、更强运动能力感知以及获得更多外界鼓励的青少年，在一年后投入有组织体育活动的时长更长；而参与障碍与运动技能无法有效预测体育参与情况；其三，上述六项因素与体育参与之间的关联均未随时间发生显著变化。

研究结论
尽管学界普遍认为中等教育初期阶段的有组织体育活动参与率会出现下降，但本研究发现该群体中相当比例人群的参与情况可保持稳定。运动动机、感知运动能力与外界鼓励，似乎是推动青少年参与有组织体育活动的关键因素。