Bending left arm in backswing .. dont do it . Or at least try and feel like you arent

Have a look at the extensor action thread espeically the drill with the string/rope. http://www.golf-tuition-online.com/g...wrist-cup.html (Extensor Action and left wrist cup)

The left arm should maintain the radius between the club and your left shoulder. Its all physcis. The wider and more extended the left arm, the more this radius is maintained and the faster you will swing

I like to feel like my left arm is almost pulling my left shoulder out of its socket. Similar to the work Greg did with a pupil in that thread. This to me is maximum width and from there you can really climb into the ball. This also keeps you from overswinging since that left arm and wrist cant collapse. Tight and Wide

http://www.iseekgolf.com/golfschool/...es.php?gs_id=4