To do the Plyo Jack, start standing tall with your feet together and your arms down by your sides. Then just slightly squat, pushing your butt back, to load your glutes so you can explode up off the ground.
You will then perform the same movement as with the Basic Jumping Jack, but instead of jumping your feet out wide on the ground, you will want to explode up off the ground as you jump your feet out wide. As you jump up off the ground, raising your legs up to the sides as you jump, you will swing your arms out to the sides and up overhead.
To land, bring your feet back together and sink back into a little squat. You want to squat a little as you land to help load your legs for the next jump while also landing softly to protect your knees. Bring your arms back down to your sides as you land and then repeat, jumping back up.
The bigger your jump and the quicker you do the reps back to back, the harder this move will be. To make the move a little easier, pause between jumps.