Exploration of the Relative Age Effect and Participation Experiences of Middle School Students in the 365+ Physical Education Activity Program

Purpose: The purpose of this study is to investigate the effect of the 365+ physical education activity program on the relative age effect among middle school students and to analyze the participation experiences of students enrolled in the program. Method: A mixed-methods approach was employed, involving 188 third-grade middle school students (born in 2009) from a rural area in Gyeonggi-do. For the quantitative analysis, a two-way repeated- measures ANOVA was conducted to examine changes in physical fitness achievement according to birth quarter (Q1–Q4). For the qualitative analysis, an inductive category analysis was performed using researcher field notes and students’ open-ended questionnaires to capture the depth of their participation experiences. Results: First, the 365+ physical education activity program significantly attenuated disparities in physical fitness performance evaluation scores across birth quarters. Second, the implementation of the program, adapted to specific school conditions and student characteristics, fostered positive experiences and encouraged autonomous participation in exercise. Third, the findings highlighted the necessity for schools to reorganize physical education policies and curricula to address the inherent developmental inequalities caused by relative age effect. Conclusion: This study demonstrates that the 365+ physical education activity program effectively reduces disparities in students’ athletic ability and foundational physical fitness. Furthermore, it confirms that the relative age effect can be moderated through deliberate instructional design. These results provide a meaningful basis for establishing more equitable physical education environments that account for innate developmental differences.