I Tried Halle Berry's Infamous Fitness Friday Core Workout, and My Abs Wouldn't Stop Shaking

Grab a foam roller and place it on the ground. Come into a high plank position with both palms on top of the foam roller. For more stability, place your feet slightly further than hips-width apart. With control, begin to roll the foam roller forward with your palms. Go as far as you can while maintaining proper form. With control, roll the foam roller back to the starting position. Complete for 30 to 60 seconds.

If this is too advanced, you can perform a high plank or a body saw.