Thumbs Up Core Crusher
Sit on the floor and scoot back to create tension on the tubes. Keep your legs in front with your, knees bent 90-degrees and close together. Hold the tubes securely in each hand in the thumbs up position. Create tension on the tubes and lean back slightly. Lift your chest so your torso and legs form a V shape, bracing your abdominal wall to engage your core. Individually extend one heel out and retract it back, then alternate to the other heel. At the same time, flutter the tubes vertically and rhythmically without letting them hit the ground. The Core Crusher method is total engagement of the rectus abdominis, and oblique system.