“The Relationship Between Abdominal Muscle Strength And Trunk Flexibility With Heading Ability In Football” (2026) COMPETITOR: Jurnal Pendidikan Kepelatihan Olahraga, 18(1), pp. 0836–0845. Available at: https://competitor.idjournal.eu/index.php/competitor/article/view/565 (Accessed: 16 February 2026).