Ron Ward, Master Personal Trainer: Gym Smarts: Advanced Core Exercises Today we gonna show you how to train the core muscle. And we are gonna use the free motions machines to demonstrate that. We gonna start by, first you would put down a comfortable weight for yourself. And then, we are gonna grab the cables pulling them together by the chin bring your left leg outward or your right leg bend it slightly. Bring the straps to your chin and downward motion hold for three, two, and one, and back up. Down again hold, three, two, and one. The improper way to do this would be to move in a jerking motion and not stop the motion. That would be an improper way to do a standing crunch.