MUSCLES ENGAGED Abdominals The abdominal muscles (abs) provide movement and support to your core area. The deeper and closer to the spine the particular abdominal muscle is, the more effect over body posture it will have, and this often contributes significantly to a healthy back. Exercise Instructions Step 1 Start on your back with your hands to your side and both feet raised off the ground. Step 2 Start fludder kicking your feet. Step 3 Complete the recommended number of reps or duration of time.