A plank jack is like a normal plank except you’ll be using your legs to create a motion.
Start this exercise in the plank position with your arms extended up and hands under your shoulders, feet will be together.
Your body will be in a straight position and head to your heels.
Jump your feet out as wide as possibly avoiding straight while doing a horizontal jumping jack.
Keep your body in the plank position while bringing your legs back together as quickly as possibly.