[Looseness]

Check this guy out on his backside tuberiding, he does thsi elbow drag in the face that makes total sense to me. If you use your arm it puts a lot of pressure at what feels to me and un-natural angle on the shoulder. By using the elbow it seems like you can use more muscle to keep the shoulder stabilized whiel you deal with the pressure of the dragging elbow.
http://www.surfline.com/video/locals/local-fire-sage-huls_45760

[little_nasty]

interesting.  only thing is that sometimes your arm gets "caught" in the wave and drags you off balance.  I still like using a hand.

[ankleslapper]

looks just like my backside tuberiding.  I know I'll do an awful job explaining this, but looks like with the elbow in the wave like that there's so much less "margin" before the pressure is exerted on your shoulder (elbow gets caught, boom, the force moves to shoulder in an instant).  totally hear loose's logic about 'muscling it' but seems like the play of a trailing hand offers a tiny bit more time/flexibility/transfer of force before the impact pull hits the shoulder.  maybe my understanding of the physics is assbackwards, but with such a short distance btwn elbow & shoulder, I can't watch that vid without imagining my arm getting ripped out of the socket (having had should/dislocation issues).

[ya_bloody_wanka]

i always thought the leg drag was the sickest technique for backside tube riding