Now I'm going to demonstrate a Swiss ball jackknife, placing it from your hands to feet. It's definitely a little bit more of an advanced exercise but one of my favorites.
I'm going to lie back with my hands behind my head, straight out. My legs lift off the floor. Then I reach, place the ball in between my ankles, and I straighten back down, stretching the torso. You're working your upper and lower abdominals when you do this, and then accepting the ball back into the hands.
Take this nice and slow until you get the hang of it. Remember, keep the back flat on the floor so you're not arching the back. You're stretching out, really getting a nice stretch, then coming up the same exact time so you can accept the ball back with the hands. Exhale as you come up. Place the ball between the feet, stomach tight so you work the upper and lower abdominals, reaching to get the ball again.
I'd do probably about 10 to 15 repetitions until you really grasp the form of this exercise. It's definitely, like I said, one of the more advance exercises. You do it properly, and you'll see amazing results. That's how you do a Swiss jackknife hands to feet.