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.
Definition of stoop. intransitive verb. 1a : to bend the body or a part of the body forward and downward sometimes simultaneously bending the kneesb : to stand or walk with a forward inclination of the head, body, or shoulders. 2 : yield, submit. 3a : to descend from a superior rank, dignity, or statusb : to lower oneself morally stooped to lying.