Group heterogeneity in the relationship between physical health level and psychological depression in college students

Due to their different majors and the gradual diversification and complexity of the things they encounter, students' thinking gradually matures, and the differences in mental health levels among individuals become obvious in the university stage. This study explores the group heterogeneity of the relationship between different physical health types of college students and their psychological depression, in order to provide scientific basis and methodological reference for alleviating students' psychological depression and ensuring their psychological health. A random sampling method was used to conduct a questionnaire survey on 1,367 students in their first year of college in Shandong Province, China, which included basic information such as students' gender and The Centerfor Epidemiological Studies Depression Scale (CES-D). Discriminant analysis, K-means cluster analysis and analysis of variance were used to subdivide and cluster college students' physical fitness test scores, and to explore the heterogeneity of the relationship between each type of clustering and psychological depression. (1) The physical fitness level of college students can be clustered and subdivided into 4 types: Physique-Functional Type, Cardio-Resilient Type, All-Around Elite Type and Speed-Endurance Hybrid Type. (2) Significant differences (p < 0.05) were found among the four different types of college students in terms of gender, as well as depressed affect, somatic and retarded activity, and interpersonal depression dimensions and overall depression levels. (3) Psychological depression levels of college students in All-Around Elite Type and Speed-Endurance Hybrid Type were significantly lower than Physique-Functional Type and Cardio-Resilient Type. There are heterogeneity differences in the depression levels among college students with different physical health types. It might be possible to predict their own psychological depression levels based on their different physical health types, with the aim of taking differentiated improvement methods as early as possible to intervene or improve the psychological depression levels of college students. Firstly, for students with more severe psychological depression, it might be possible to improve their depression levels by prioritizing the provision of targeted training programs that enhance explosive power, endurance, and cardio-pulmonary function. Secondly, for students with relatively stable psychological depression but poor physical fitness, combined with aerobic exercises, training aimed at improving physical functions should be provided. Finally, for students who have already shown excellent overall performance, efforts should be made to maintain and further enhance their comprehensive physical abilities.