Physical activity determinants, 24-h movement behaviors, and cardiovascular fitness in young adults: an integrated theoretical model perspective

Purpose Guided by Social Cognitive Theory and the Transtheoretical Model, this study examined differences in physical activity (PA) determinants, 24-h movement behaviors, and cardiovascular fitness (CRF) across stages of change among Chinese college students. Associations between PA determinants, movement behaviors, and CRF were also examined. Methods Participants were 220 Chinese college students (105 males; M age = 20.15 ± 1.01 years). Students completed validated questionnaires assessing PA determinants (i.e., PA strategies, decisional balance, self-efficacy, social support, enjoyment, and perceived environment). One week of 24-h movement behaviors (sedentary time, light PA, moderate-to-vigorous PA [MVPA], sleep duration and sleep efficiency) was assessed using ActiGraph Link accelerometers. CRF was assessed using a standardized 3-min step test. Results Participants classified in higher stages of PA behavior change reported significantly more favorable PA determinants than those in lower stages, including higher self-efficacy ( p < 0.01, ƞ 2 = 0.12), decisional balance ( p < 0.01, ƞ 2 = 0.034), PA strategies ( p < 0.01, ƞ 2 = 0.05), friend support ( p < 0.01, ƞ 2 = 0.06), and enjoyment ( p < 0.01, ƞ 2 = 0.07). No significant stage-group differences were observed for accelerometry-derived measured movement behaviors or CRF. Regression analyses showed that MVPA ( t = 1.96, p = 0.05) and self-efficacy ( t = 1.84, p = 0.06) were the strongest contributors to CRF. Light PA ( t = 16.73, p < 0.01) positively predicted with MVPA, whereas sleep efficiency was negatively predicted with MVPA ( t = −2.00, p < 0.01). Additionally, MVPA and sedentary behavior ( t = −4.87, p < 0.01) were significant negative predictors for sleep efficiency. Conclusion College students with high stages of PA behavior change demonstrated more positive psychological determinants of PA, though objective activity levels and fitness did not differ. MVPA and self-efficacy emerged as key influences on CRF, highlighting the importance of motivational and behavioral regulation strategies in college-based PA promotion and support the development of stage-tailored, theory-informed PA interventions for college students.