So I am gonna demonstrate for you how to do a jack knives on a Swiss ball. This is a very advance abdominal exercise so I would definitely start out with something more basic. If you are not too sure you could do something like this may be do a prone plank, progress from their to a two point plank. its stability, its strength and its also a lot of core involved in this. So! jack knives! we are gonna start out with the ball behind us. You are gonna get to a plank position on your hands. You are gonna control the ball using your foot here. You want both feet on the ball. So I would recommend using a ball about this size because if the ball is higher you are gonna have A, more trouble stabilizing and B, you don't want your hips being too high when you are doing this exercise. You want it kinda be level as if you were you body was like a surf boat.
So one ball, one foot is on the ball other foot now unstable. I feel safe! I am ready to rock! jack knives!
So you are gonna bring your knees into your belly and back out. I am gonna back a little bit just because I want to get more ranger motion. So knees! back out! knees in! back out!. So I don't wanna see your hip is dropping too low, you are not bending the arms, arms are locked!. All you are doing here is bending you knees in towards you rolling the ball with the movement coming in with your knees. So the ball is rolling inward and then I am pushing it back out. Inward! pushing it back out!. So as you can see its a pretty challenging ab exercise but its great, its one of my favorites. It's definitely good because it works stability and strength as well as all the front abs as well as your internal external obliques and that's how do you do jack knives this was all.