Originally Posted by waterrockets

This thread is too long for the subject. I stopped reading around post 18.

Pro sprinters do intentionally swing the bike. They are increasing pedal force by pulling the bars away from the pedal during the downstroke. It's like how you would tear carpet once a rip has started, using a foot and a hand.

It's just plain more powerful to swing the bike if you do it right. Here's a video I added a while back, with Robbie illustrating the technique. Notice how he pulls away with each pedal stroke.