Aufar, Reza Fadhlillah, Soegiyanto Soegiyanto, and Tri Rustiadi. 2019. “Plyometric Exercises and Concentration Levels on the Swim-Start Jump of Female Athletes in Metro Lampung”. Journal of Physical Education and Sports 8 (4), 8-14. https://journal.unnes.ac.id/sju/jpes/article/view/31356.