Jules Keller “The Upside Down Man” was a handbalancing star attraction in the early 1900’s. We have long said that the regular practice of handbalancing will build unusual strength and development in the forearms and this example is certainly case in point. Supporting the entire bodyweight on the wrists and using the fingertips to maintain balance trains the lower arm musculature in ways that no other method can match.
Keep in mind, Mr. Keller only weighed 150 pounds, has there ever been a more impressive display of the development of that muscle group? (even a hundred years later?)