With the widespread adoption of smartphones, mobile phone addiction has increasingly gained prominence among Chinese college students, exerting a profound and detrimental impact on their learning engagement. This study employs self-determination theory as a framework to examine the mechanisms through which mobile phone addiction affects students’ learning engagement. Specifically, it examines the mediating effects of physical activity and academic self-efficacy in this relationship. This study was conducted from March to June 2024, using the Mobile Phone Addiction Scale, Learning Engagement Scale, Physical Activity Scale, and Academic Self-Efficacy Scale among college students from eight universities in Shaanxi Province. The survey was conducted using the Chinese online questionnaire platform “Questionnaire Star,”and 4,562 valid questionnaires were finally obtained. SPSS 29.0 and AMOS 29.0 were used for data analysis and structural equation model testing. The results revealed significant negative correlations between mobile phone addiction and learning engagement (r = -0.434, p < 0.01), physical activity (r = -0.732, p < 0.01), and academic self-efficacy (r = -0.338, p < 0.01). Conversely, there were significant positive correlations between learning engagement and physical activity (r = 0.335, p < 0.01), and academic self-efficacy (r = 0.717, p < 0.01). The study’s hypothesized model demonstrated a good overall fit, with indices including χ²/df = 4.213, RMSEA = 0.040, and GFI, AGFI, NFI, and CFI all exceeding 0.90. Mobile phone addiction was found to directly impact learning engagement (point estimate = -0.150, p < 0.001) and indirectly through three mediated pathways: physical activity (point estimate = -0.068, p < 0.001), academic self-efficacy (point estimate = -0.298, p < 0.001), and their chained effect (point estimate = -0.377, p < 0.001). This research has expanded the theoretical framework and intervention approaches regarding the inter-relationship between mobile phone addiction and learning engagement. Increasing individuals’ physical activity levels and fostering their academic self-efficacy offers a means to alleviate the detrimental impact of mobile phone addiction on the learning engagement of college students.

Objective: To explore the effect of problematic mobile phone use on college students’ physical activity and their relationships. Methods: A cross-sectional study was conducted among 3980 college students from three universities in Jiangsu province by random cluster sampling. The International Physical Activity Questionnaire Short (IPAQ-SF) measured college students’ physical activity. The Mobile Phone Addiction Tendency Scale for College Students (MPATS) measured problematic mobile phone use tendencies. College students’ physical activity was measured by the International Physical Activity Questionnaire Short (IPAQ-SF), and the Mobile Phone Addiction Tendency Scale measured their mobile phone addiction tendency for College Students (MPATS). Results: (1) The proportions of the low-, medium-, and high-intensity physical activity were 83.5%, 10.7%, and 5.8%, respectively, with gender differences; The score of problematic mobile phone use tendency was 38.725 ± 15.139. (2) There were significant differences in problematic mobile phone use tendency among college students with different physical activity intensity (F = 11.839, p < 0.001, η² = 0.007). (3) The level of physical activity was significantly correlated with the tendency of problematic mobile phone use (r = −0.173, p < 0.001). (4) Physical activity of college students could significantly predict the tendency of problematic mobile phone use (F (3,3605) = 11.296, p < 0.001). Conclusions: The physical activity of college students was mainly moderate to low intensity, while the tendency of problematic mobile phone use was high. College students’ physical activity level was one of the important constraints of problematic mobile phone use tendency.