The story goes, the Greek physician Hippocrates would gives his patients animal skins filled with sand to throw around - essentially, healing them.
From Persian wrestlers and the ancient Greek athletes and physicians, to the Roman Gladiators, to Renaissance physicians, as well as the US Military Academy at West Point for over 200 years and "Hoover Ball", which was a game President Hoover's physician prescribed him to stay fit...
"As long as there have been athletes, there have been medicine balls." - Istvan Javorek.
"Exercises with the Medicine Ball" by William J. Cromie. 1906.
UND Volleyball throwing the healing ball around in the early morning hours.