Ball Plank Show Video Show All Exercises     Primary Muscle Group: Core Muscles Muscle groups worked in this exercise: Abdominus Rectus, Internal and External Obliques Preparation: Kneel on the floor with the ball about a foot in front of you. Both forearms are placed upon the top of the ball, palms together and fingers interlaced. Pull your navel up close to your spine. Breathing: Exhale as you lift your knees, Inhale when you return knees to the floor. Breathe normally while holding the plank position. Execution: As you lift your knees and straighten your legs, you'll be balancing on your forearms and balls of your feet. If you'd like to make this a little harder, place your legs closer together. Hold for up to 1 minute as you breathe normally. Here are a few suggested alternative exercises: Ab Crunch Ab Crunch Obliques Ball Crunch Traditional Double Crunch Dumbbell Side Bends Lateral Bend with Barbell