“The Relationship Between Interval Training Frequency and Aerobic Endurance Level Among Futsal Extracurricular Students at SMPN 3 Ungaran” (2025) COMPETITOR: Jurnal Pendidikan Kepelatihan Olahraga, 17(2), pp. 1909–1916. Available at: https://competitor.idjournal.eu/index.php/competitor/article/view/97 (Accessed: 19 March 2026).