Giancarlo Stanton Adjustment to Swing Mechanics 
This is a great article on HittingDaily.com about Staton's change in swing mechanics. He breaks down his swing into fluid components that are all interconnected. To often, high school players release all of the swing elements at one time - essentially leading to spinning like a top. Hitting is about generating energy from the ground up. The load (hands) start with the hips and legs, then works up to the shoulders - all with the hands back. Hands then come straight through the ball leading to a full extension at contact point. Take a close look at the before and after comparison below. In the lower image, see how his hands load when his hips begin to fire. His hands are then triggered by the shoulder movement. Look at the differences in his contact point.