[12 piece bucket]

HB - I think that going from a bent knee position in the downswing to a straight left leg position at impact is nothing more than the O factor principle - as described by Robert Baker in his swing video lesson. It simply depends on how much of a positive O factor one wants to acquire at impact. Some golfers like Tiger Woods have a very straight left leg at impact (which is partially responsible for his left knee damage) while other golfers keep their left knee slightly flexed at impact.

See -http://www.golf.com/golf/video/artic...595277,00.html

I agree with Robert Baker that it is a good idea to have a positive O factor at impact, but greater amounts of O factor do not necessarily correlate with increased clubhead speed. One only needs enough O factor to get secondary axis tilt that allows the right shoulder to move downplane, which allows for the correct in-to-square-to-in clubhead swingpath when PA#4 releases the left arm into impact.

Jeff.

Interesting stuff in regards to extension and flex.