For carver_hk: a note for the physics experts (from Lind and Sanders - The Physics of Skiing). In Technote 10 there is a discussion of pumping in a turn. If a skier is in a turn, and moves his COM towards the center of the turn, his/her speed will increase. This is caused by the fact that the Kinetic Energy of Rotation does not change, but the radius that the COM is describing decreases. (I think someone else also suggested reading this).
So it is not necessary for the ski to bend more to pick up speed - thought it may also help. All that is required is that the skier move his/her COM toward to center of the turn, and speed will increase!!!. Conversely, if the COM moves out, the speed will go down.