Russo, Luca, Johnny Padulo, Francesco Oliva, and Nicola Maffulli. 2021. “Letter to Editor Concerning ‘Push Up, Explosive Push up and Free Fall Tests to Evaluate the Upper Body Power: A Preliminary Study in Aerobic gymnastics’”. Journal of Human Sport and Exercise 16 (4):996-99. https://www.jhse.ua.es/article/view/2021-v16-n4-letter-editor-push-explosive-push-free-fall-tests-ev.