Pikes of Death
For this exercise you will need a wheel that can be put on your feet and a BOSU balancer. This can also be done with a stability ball in place of the wheel. Make sure you securely strap your feet into the wheel straps and go right into a full body plank (push-up position). Once you are stable and holding that plank, push your buttocks toward the ceiling and form a Letter-A. Hold that position for a few seconds, then release back to a full body plank. Do this exercise for three sets of 30 repetitions. On your last repetition perform another Isometric hold (hold while flexing) in the Letter-A position for 30 seconds.
Sit-Up to Squat with 10lb Medicine Ball
This last exercise is going to get your heart racing. From a sit-up start position, have someone hold your feet/ankles. I usually don't recommend someone holding your feet, but if you are extremely in shape and have no lower back or knee problems, then this will be OK.
Place the medicine ball at your chest and come up as fast as you can with momentum. When you are going up, start activating your quadriceps, gluteus muscles and hamstrings to bring you into a standing position. Once you are almost in a full standing position your spotter can let go of your feet and let you come down by yourself with the medicine ball.
This is an advanced exercise, so if you need to break it up into several sets, please do so. Do this for three sets of 20 repetitions. It is OK for the medicine ball to come off your chest for momentum, but the stronger you get the closer the medicine ball will stay against your body.
Tone up your abs. Find a core class.