Sport development index as a predictor of physical activity and aerobic fitness: evidence from Indonesian universities with regional contrasts. - Fikri, Muhammad Dzul; Sudijandoko, Andun; Purnomo, Mochamad; Kusuma, Donny Ardy; Özman, Cemal; Rusdiawan, Afif; Rohman, Mohammad Fathur; Srie Wardani, Aulia Putri; Sholikhah, Anindya Mar'atus; Firmansyah, Awang; Lestari, Bhekti; Ar Rasyid, Muhammad Labib Siena (Retos: Nuevas Perspectivas de Educación Física, Deporte y Recreación, 2026)