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 #1 reason why people find deep squatting difficult. What is the Deep Squat? The deep squat describes a position in which one is resting in full flexion of the hips, knees and ankles with the feet on the ground. The deep squat is a comfortable resting position which is more stable than standing because of the low center of gravity.