I have been watching film clips of one of the greatest performers of the 20th century, Donald O'Connor. Born and raised in Vaudeville, he could sing, dance, act, do acrobatics, and was a master at comedy. Here is his famous "Make them laugh" number from the 1952 musical film, "Singin' in the Rain". Watch to the end. The only time I have ever seen anyone run up a wall and do a back flip.