
16. Plank Jacks
Planks are already a pretty hardcore exercise that strengthens your core, and it not only improves stability but also puts your back muscles to work. Adding a medicine ball changes how planks work. However, it adds an unstable surface to engage your core muscles further. But before you start doing medicine ball plank jacks, you should first master plank jacks since they’re not easy to do. Plank jacks are where you do a plank and then jump to spread your legs apart. Think of bouncing back, but you’re horizontal and only moving your legs.
To start doing a medicine ball plank jack, get into a kneeling position on the ground. Your hands should be cupped around the medicine ball on the floor to find your center of balance. Tighten up your abdominals and glutes, and stretch your legs out behind you in a straight line. Straighten your arms to be in a pushup position on the medicine ball. Tighten your core, jump your feet to a shoulder-width apart, and then jump back together. Continue this motion without letting your body bounce too much.