Given names often turned into family names when people were identified by their father's name. For example, the first name Ahrend developed into the family name Ahrends by adding a genitive s-ending, as in Ahrend's son. Examples: Ahrends, Burkhard, Wulff, Friedrich, Benz.
OK the definition you have used for crouching associates it with stooping (which on Wikipedia redirects to bowing. Squatting essentially involves bending at the knees and hips. If there is any bending at the waist (and maybe lowering of the head) then that is considered stooping.
The Wall Squat. What is it: A squat performed whilst standing close to and facing the wall, with your hands against the wall but no other part of your body permitted to touch it. How to do it: Stand a foot's width (as opposed to a footâs length) away from the wall in a shoulder width stance.