This week we are going to focus on your core. I like this simple exercise because it works all of your abdominal muscles: inner/outer, upper/lower, and sides. That said, this is not a cardiovascular exercise so make sure you add it in with other moves that will get your heart rate up.
Begin on your back with your knees bent, feet on the floor. Pull your belly in toward your spine, relax your neck, and put your hands palms-down on the floor. Now, place a ball (preferable a weighted ball) between your knees and press your legs together to hold the ball in place; you should feel this activate your inner thigh muscles. Keeping this position, lift your feet off the ground slightly to begin your Ab Circles. Pretend you are going to draw a circle with your knees, bringing the ball to the left, up into your chest, to the right, and back to an inch off the floor. To really get the most out of this exercise, really twist your hips to each side and draw as big of a circle as possible. Do 10-20 circles counter-clockwise, then 10-20 circles clockwise. Repeat 1-2 more times.