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. Obliques Many people put a lot of focus on working their abs but forget their surrounding neighbors; the oblique muscles. Obliques serve as stabilizers, and are used in almost every physical activity. Exercising your obliques should be a very important part of your workout program. Exercise Instructions Step 1 Pull your knee in towards your chest and cross your body over so your elbow is touching your knee. Step 2 Extend your other leg out towards the floor. Step 3 Pull your leg back up to the starting position and repeat.