Lie on your back on an exercise mat. Your knees are bent to 90 degrees and your feet are flat on the mat. Your arms are placed along your sides, flat on the mat. Curl your pelvis forward slightly and raise your pelvis in the air, attempting to create a straight line from your shoulders to your knees. You'll feel a muscular contraction in your stomach muscles and gluteal muscles. Relax and return to the starting position.