Medicine Ball Suitcase Crunch
Begin by lying on your back on the floor. Your legs should be straight and your arms extended over your head holding a medicine ball.
Tuck the knees toward your chest, rotating your pelvis to lift your glutes from the floor. As you do so, flex the spine, bringing your arms back over your head to perform a simultaneous crunch motion. Pause for a second.
Return to the starting position and repeat the exercise according to the training plan.