• Sit on stability ball facing partner who’s holding med ball

• As he tosses med ball to you, catch it, twist to right, twist to left and then perform crunch

• At top of crunch, throw ball back to partner with chest pass

Form matters: “When you twist to the right, twist until you can touch your right elbow to the stability ball and vice versa twisting to the left.”

Why he does it: “This also works reaction and stabilization, but adds rotational core strength since you twist in each direction.”