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. Equipment Used Stability Ball A stability or exercise ball is a ball constructed of soft elastic and filled with air until firm.Most stability balls range from a diameter of approximately 35 to 85 centimeters (14 to 34 inches). Bench A weight training bench is a piece of equipment that has a resemblance to a normal (e.g. park) bench, but is cushioned and designed for use in the weight room. Exercise Instructions Step 1 Start in a plank position on the ball with your feet up on the bench. Be sure to have your hips down and tucked, your back staright and your abdominals contracted and tight. Step 2 Slowly breath out and squeeze the muscles of your core as you push the stability ball out. Push the ball out as far as your abs will allow before your body tries to engage the muscles of the lower back to help support the weight of your body. Step 3 Pull you elbows back in to your body as you inhale you next breath of air and repeat action.