this makes me think of that scene in The Holy Grail when the monks go walking by chanting in Latin and hitting themselves in the forehead with a wooden board at the end of each verse.....

so yes, folks do it but its really not my thing and I don't really get it ;-)
especially given my age and the "low torque, high rev" sort of knees that I've always had. Beefier folks probably do better.

but hey, its all "bike" so its cool.