HOW: For this exercise begin in a plank position with your body parallel to the floor with your elbows under your shoulders and your feet hip width apart. From here, pretend you are performing a jumping jack by quickly spreading your feet farther apart, landing on your toes, and then bringing your feet quickly back together to the starting position. Perform for the given amount of reps.
FEEL: You should feel your core musculature, shoulder muscles and glute and quad muscles engage while you perform this exercise.
COMPENSATION: Avoid arching through your back when performing this exercise. Keep your core engaged and strong as you perform the jumping jack motion.