Grab an exercise ball.

Interlace your fingers and place your forearms on the top of the ball.

Extend your legs out so that only your toes are touching the floor.

Straighten your body out. Hold this position for as long as possible.

Repeat for desired reps.

Exercise Tips:

Make the exercise ball plank harder by resting one foot on top of the other and only leaving one foot on the floor.

You can also do this exercise with your hand on the ball instead of elbows/forearms.