People who use telemark skis in which the heel is free from the binding as opposed to downhill skiing with which the heel is locked into the binding. Thus, these types of skiers have to drag there knee on the ground to make the tight turns which come so easily to the downhill skier.
"My telemark skiis are like, wayy sicker than your alpine set-up." "Shut up, stupid knee dragger."
A person that rides a motorcycle, particularly on a race track, that is able to turn in such a way, and at such a velocity, at such a low height, that their knee drags against the ground.
Casey Stoner, a professional MotoGP racer, is able to drag a knee through his turns. This is an example of a knee dragger.