"Photo of  Navajo Canyon, Mesa Verde National Park"

Note: although this is called Navajo Canyon,
it has recently been asserted that the cliff dwellers were NOT Navajo, but Puebloan
by the current Puebloan people.

I included this photo to illustrate the intensely harsh environment
 where the cliff dwellings are found

snow at 8.000 ft up in winter would have been regularly occurring

Moving around to get water, food and visit other villages developed super-fit bodies
(no need for fitness centers in these communities!)