Here's fitness guru Jack LaLanne in the 1950s, balancing on a chair. LaLanne typically wore ballet slippers on his workout show. According to a 2010 blog post on his site, "In those days tennis shoes were not popular, and only used to play tennis in... Most show business people and Hand Balancers wore ballet slippers, and Jack being a Hand Balancer, that was what he wore!"
Jack LaLanne, according to Barbend.com, "regularly practiced hand balancing — basically, performing stunts like push-ups, distance walks, and timed holds all while in a handstand. All that time upside-down helped [him] build chiseled shoulders and arms, along with strong, tight abs." Now you know!