" I ran, jumped, squatted and – of course – worked up a sweat during two hour-long boot camps. "

Too too funny  .-)
Two hour long "boot camps" .....

How be I show you a real work out - head into the bush first thing AM, with chain saw, axe, fuel mix ... work all day cutting timber or fire wood, manhandling a very dangerous tool, felling trees, dragging heavy branches, -20C, heavy work shirt, hard hat to keep your head safe from falling junk above, long johns & jeans, steel toed work boots ... camp fire to heat lunch .. then back at it until say 4 PM  .-)

I am now over 70 and can still do it ...... try to keep up  .-)