[Hennybogan]

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.

What makes you believe that straightening the legs at the right time has no effect on clubhead speed. Can you explain that biomechanically?

What does "not necessarily" mean. Hitting the driver far is not all about clubhead speed. Launch conditions.....

Do guys that hit drivers far and high tend towards straighter or more bent legs at impact and beyond?

I would be really careful about using any Robert Baker beyond positive O factor at impact or beyond.