This is a great plyo exercise for developing power by adding weight to the plyo jump. You gotta tighten your core and really stabilize your body to complete this jump. I also try to hold the ball away from my body as I explode on to the box adding a balancing element to the exercise.
The bugger the ball the more challenging it is!
*Make sure your tighten your core throughout the exercise
*Snap your knees as you jump to the top of the box
*Think "explode up, land softly"