Running on a rebounder, also known as a mini trampoline, is a great option for enhancing running fitness in a way that complements running outdoors and provides a low cost, convenient means of training indoors during bad weather or just for a fun change. The soft surface will allow for adding more miles with no pounding, and when it's hot out, being inside will likely result in more overall training. The plyometric element strengthens muscles, tendons, and ligaments in a different way from outdoor running.