Note: Only attempt this modified plank if you have been working with the previous exercises to build your core strength. Do not attempt to do a plank if you feel your core is still weak, or if you do not yet know how to target your transverse abdominal muscles.
Start in a forearm plank position, knees on the ground, feet in towards your seat. During the time you are holding this plank, focus on bringing your belly button in towards your spine and holding it there, all while breathing deeply and engaging your inner transverse abdominal muscles.