A study compared the drawing in method to a maximal abdominal contraction method, and it showed that the maximal abdominal contraction method produced significantly more recruitment of all abdominal muscles over the drawing in method. So, how can we get better recruitment of all the abdominal muscles? Work the max abdominal contraction method! To do the maximal abdominal contraction method, they had subjects lie on their back with knees bent. They were asked to squeeze a ball between their knees