Start Position - Athlete has one foot on a box or bench, just high enough for a 90 degree bend in the knee. Arms at 90 degrees, same as proper running form.
Movement - Drive up with the bent leg and jump vertically above the box. As you reach your peak, switch leg position by bringing the ground leg up to be the landing leg. Return to the starting position and repeat. Make sure you have balance then repeat this movement on the same leg for the number of reps. required.
Repeat - If the workout calls for 10 reps. be sure each leg has made the explosive movement.