Maximum Core Stiffness
In this video, Dr. Stuart McGill works with elitefts™ team member Brian Carroll. As you watch, pay attention to Brian's torso and hip hinge movement. This exercise is not intended to train the legs, but to train the core. Remember, when you think of core, think of the quadratus lumborum, erectors, lats, and glutes. The point of this exercise is to reinforce staying tight and as locked in as possible.
This should also be VERY similar to the way you start the descent in the squat.