Table 1_Does learning burnout link physical exercise and problematic short-video use? Evidence from a three-wave random-intercept cross-lagged panel model and supplementary machine-learning analysis among Chinese high school students.docx

Supplementary ridge regression and extreme gradient boosting models, using nested cross-validation and a holdout test set, examined the incremental predictive value of physical exercise and learning burnout for later problematic short-video use.</p>Results<p>At the between-person level, higher long-term physical exercise was associated with lower learning burnout and problematic short-video use, whereas higher learning burnout was associated with higher problematic short-video use.

At the within-person level, higher-than-usual physical exercise predicted lower subsequent learning burnout and problematic short-video use. Learning burnout and problematic short-video use showed positive reciprocal associations over time, and both predicted lower subsequent physical exercise. The longitudinal indirect association from physical exercise to later problematic short-video use through learning burnout was statistically significant but small.

In supplementary machine-learning analyses, the best holdout R² was 0.311, but adding physical exercise and learning burnout did not improve prediction beyond prior problematic short-video use. SHAP results from the extended XGBoost model were therefore interpreted as exploratory feature attributions.</p>Conclusion<p>Physical exercise, learning burnout, and problematic short-video use showed interconnected longitudinal associations among Chinese high school students.

Learning burnout may represent one small longitudinal indirect pathway linking physical exercise to later problematic short-video use, while recent problematic short-video use provides the most informative signal for future risk. These findings may inform the development and evaluation of school-based health-promotion strategies that support physical exercise, address learning burnout, and respond to recent problematic-use symptoms.</p>