We rewound Fielder over and over. Commenting how sudden he was. How short he was. How it looked like he wasn't even swinging hard. Then just a couple minutes later I think it was Kruk that said "man, these guys have such short swings."
Just stare at the ball on Fielder's and Pederson's gif. You don't even see any movement in your peripheral, then SNAP the balls gone. It's like they look like they can just wait so long and POP, balls 440 feet away.
Look at each and see how violent the resistance on the back leg is after it has to yield. I think all but one demonstrate the front foot off of the ground at ball release as the core is loading.