“Improving Learning Outcomes of Underwear Passing In Volleyball Through The Use of Plastic Ball Media For Grade IV Students of SD Inpres Mare”. COMPETITOR: Jurnal Pendidikan Kepelatihan Olahraga, vol. 17, no. 3, Oct. 2025, pp. 2937-51, https://doi.org/10.26858/cjpko.v17i3.418.