mox,

i agree with the whole "just because tiger says so" does not mean it is correct.

that being said, I do believe that there is a SLIGHT dowward force (probly less than .001psi) but I don't think that force that pinches against the ground has any effect on the ball.

the main purpose to hit down on the ball is so that you hit the ball 1st and the ground next. the reason you get more distance from hitting down on it has nothing to do with pinching, and little to do with delofting, but mostly it is from pure contact with the ball vs, turf slowing of club a bit then ball. as you said with sand, you can swing full blast but because you get sand between the club and ball you don't hit it very far at all.

btw, when i spoke of hitting the ball out of the sand and how the ball does not depress into the sand (once that ball does move .000001mm down in the sand, the groves and loft roll the ball up the face as brians link show) and it goes up and out like in that post i was refering to fairway bunkers, not greenside bunkers, where you want to hit the ball 1st before the sand via a descending blow so that you get maximum contact and power transfer and good spin and high launch if there is a big lip in front of you.

i agree it is a good swing thought, but that fact that the "pinching" actually adds to the distance.... that is one thing I would need to see some seroius research to prove that. but does it actaull impart a downward force (no matter how small or insignificant)? yes, i believe it does