Study on the impact of multiple factors on 4-year physical fitness test results of undergraduate students at a Chinese comprehensive university: based on the mediating role of exercise habits

This study employed a 4-year longitudinal tracking design with 1,154 undergraduate students at a comprehensive university in northern China as research subjects, and systematically explored the pathways through which multiple factors are associated with physical fitness and health via exercise habits using structural equation modeling and cross-lagged panel analysis. The research findings revealed: the Physical Fitness Composite Index (PFCI) decreased from 73.26 points at enrollment to 68.52 points at graduation, while exercise habit intensity decreased from 4.82 to 3.54 over the same period; exercise habits served as a statistically significant partial mediator in the process through which individual factors (self-efficacy, exercise motivation, health beliefs), social factors (peer support, family influence), and environmental factors (facility accessibility, time management) were associated with physical fitness and health, with indirect effects accounting for 39.2–60.9% of the total effects; exercise self-efficacy was the strongest individual predictor ( β = 0.46), while time management pressure showed a significant negative association ( β = −0.21); initial exercise habit intensity was significantly associated with long-term changes in physical fitness and health, with the high exercise habit group showing an annual average decline of 0.94 points, significantly lower than the 2.27 points in the low exercise habit group; the second semester of sophomore year and the first semester of junior year were identified as critical turning points for the decline in exercise habits. Grade-level moderation analysis further revealed that the predictive strength of exercise habits on PFCI increased progressively across academic years, and that peer support emerged as the dominant predictor during the critical transition periods. The research results suggest that stable exercise habits may represent an important factor associated with college students’ physical fitness and health levels, and that the construction of systematic approaches from multiple dimensions including individual cognitive reinforcement, social support cultivation, and environmental condition optimization may warrant consideration, with particular attention to targeted interventions during critical periods and differentiated support for high-risk groups.