Single Leg Step Hop
This exercise is best performed whilst working on the same leg throughout the movement, then changing to the opposite leg.
Stadium stairs will offer a good platform to work off, however make sure the stairs are strong and secure enough to support a heavy pounding.
If the steps are close together you can make a number of small jumps at speed to reach your desired number of repetitions, or alternatively you may decide to explode upwards skipping one or even two steps with each hop, however this will depend upon athletic ability.
Focus on keeping the time on the ground with the jumping foot to a minimum whilst maintaining a fixed ankle and slightly bent leg position.