Hip drive is one of the magic keys to the kingdom in the Olympic lifts. If you can figure outhow to do it well, it’ll drastically increase the speed and power of your movement.
When the bar passes your knees, drive your hips into it.
The extension of the hips must be extremely violent, and the legs should continue pushing against the floor until it’s completed. The hips need to come into contact with the bar—in no instance should a lifter finish a pull without the bar being in full contact with the hips (or upper thighs in the clean).
This final extension of the hips is extremely quick and the hips snapping into the bar violently allows a faster reversal into the pull and squat under the bar. However, this has to be balanced with the need to not push the bar forward. The farther forward the hips reach to the bar without contacting it, the farther the bar will get pushed out.In other words, we want to keep the bar and body as close as possible until they contact each other at the hips, avoiding excessive distance.