HOW: You can do this exercise both as a static or dynamic workout. Most effective is the dynamic motion which requires both strength and coordination; Lean forward on a chair with wheels and assume the plank position, lower arms resting firmly on the cushion and upper arms in vertical position. Let the chair roll forward away from you as far as you can manage and then pull it back towards you again. Repeat! It’s a very effective workout and you will instantly feel your abs getting a full rundown.
It’s easier as a static workout. Then you just lean forward in a plank position and hold for as long as you can. You can also do this on a chair without wheels.