Every human should be able to do a flat-footed squat
(www.survivalandserenity.com)
Stamina jogging sounds like an excellent survival skill! It took me a while to work up to a full squat but I would do the "2×4 under my heels" trick while I watched videos and now I squat all the time; shopping, gardening, building things, cleaning; it is very useful to be able to use the floor as a table!