Position box on a non-slip surface. Start about 6 inches away and step on top of the box making full contact with the surface. Pull your body up through the heel of the foot that is up on the box. Power your opposite leg up by driving your knee forward. Explode up through heels for a brief hop & land softly on balls of feet. Lower yourself back down to the floor with full control. Repeat this movement for all reps and then switch legs.