A profile of the late Jack LaLanne, “the greatest gym teacher of all time,” who was as responsible as anyone for America’s fitness craze in the latter half of the 20th century.

In the British sport of “ferret legging,” underwear-less competitors tie their trousers at the ankles, stuff a pair of the carnivores down there, and hold on for as long as possible. Reg Mellor is the world’s best.