Table 2.

Reliability and CFA evidence

Measure/model	n	α or χ²/df	CFI	TLI	RMSEA	SRMR
Future anxiety (DFS)	1271	α = 0.803	—	—	—	—
Physical activity habit automaticity (SRBAI-PA)	1271	α = 0.819	—	—	—	—
Brooding rumination (BR)	1271	α = 0.860	—	—	—	—
Academic burnout (SBI)	1254	α = 0.904	—	—	—	—
Harman single-factor PCA	1254	First factor = 29.61%; eigenvalues > 1 = 4	—	—	—	—
Four-factor model	1254	1.180	0.997	0.996	0.012	0.022
3-factor: FA + BR combined	1254	7.722	0.870	0.855	0.073	0.078
2-factor: FA + BR + AB combined	1254	16.238	0.703	0.672	0.110	0.114
Single-factor model	1254	22.624	0.576	0.534	0.131	0.134

CFA and reliability for academic burnout were estimated using item-complete cases (n = 1254), whereas the main regression models used available-item mean scoring and a complete-item sensitivity analysis was also conducted. CFA was estimated using maximum-likelihood estimation in Python 3.11

CFA confirmatory factor analysis, RMSEA  root mean square error of approximation, SRMR  standardized root mean square residual