“The Effect of Arm Power Training On Upper Service Ability In Volleyball Games of Extracurricular Students of Palu Salvation Army Christian Junior High School”. COMPETITOR: Jurnal Pendidikan Kepelatihan Olahraga 17, no. 2 (August 6, 2025): 1792–1800. Accessed August 24, 2025. https://competitor.idjournal.eu/index.php/competitor/article/view/260.