According to Dr. Susan Brown in her OsteoBlast newsletter, hopping 100 times a day will help bones get stronger, making them less susceptible to injury:
Remember jumping rope and playing hop scotch as a kid? Well, it’s time to think about those activities again, because hopping and jumping are great bone builders. As it turns out, bone strengthens in response to the load placed upon it, and high-impact activities like jumping load bone much more than low-impact activities like walking. Studies among children and adults show the bone benefits of this simple form of high impact exercise. Ten to 15 minutes of heel drops, hopping, or jumping three days a week helps to increase bone density and strength.
Coaches – you can help your athletes get 100 hops in by setting up return stations and drills that incorporate jumping, bounding,