1. Vertical Toe Touches
Lie on your back with your legs extended straight up. Use your abdomen muscles to lift your torso off the floor as you reach your hands towards your toes. Return to starting position, and repeat.
2. Mountain Climbers
Start in push-up position. Bend on leg and bring the knee to the opposite elbow. Return to push-up position, then switch legs and repeat. Try to avoid bowing up your back.
3. Windshield Wipers
Lie on your back, legs extended vertically in the air, arms resting on the floor in T position. Keeping your back on the ground as much as possible, lower your legs together down to one side. Return up to center, and then lower to the other side. Repeat.