WR, I think what the op was asking, was why isn't rocking the hips outside of sprinting good if rocking the bike while sprinting is, and why is it bad if he feels more powerful...
I see.
Originally Posted by
gregf83
The bike moving from side to side is not inefficient.
Yes, it is. Stand next to your bike and shake it side to side for 15 minutes. Compare how tired you are with how much faster you're moving.
This minor inefficiency is worth it, because it allows you to increase pedal force and essentially pedal with your arms and legs at the same time.