2024. Do exercise for 4 weeks using rubber to increase the speed of gyaku tsuki karate punches gokasi karate athletes aged 16-20 years? . Jurnal SPORTIF : Jurnal Penelitian Pembelajaran. 10, 3 (Dec. 2024), 390–404. DOI:https://doi.org/10.29407/js_unpgri.v10i3.23115.