https://www.theguardian.com/film/filmbl ... ilm-stuntsUndeterred, Keaton claimed that he never refused a stunt, however dangerous; in fact, he frequently doubled for other actors when they needed to take a fall. That’s because he was a pro, who had learned to land soft and withstand a few knocks from his childhood in vaudeville, playing The Little Boy Who Can’t Be Damaged in a family act. For Keaton, it was almost second nature to “land like a cat”, using the art he called “body control”.
Here's a clip I came across earlier today. Some obvious editing with the tree part, but still impressive stuff.