I was working out yesterday at a local gym and I saw several young athletes working out.....I always like to see dedication to your sport---the best indication of dedication is working out on your own (without a coach telling you to do it)....
I also saw something I don't like to see: they were spending too much time strengthening their arms and legs and not nearly enough time strengthening their cores! Big mistake young fellas (I got to talk to a few)!
The key to lessening your risk of injuries and maximizing your arm/leg strength and power is to strengthen and stabilize your core! A stronger core gives you stronger and more powerful arms and legs! A strong core also makes you faster for a longer period of time (speed endurance).
If your core is weak, you are not ready for high-speed, high-risk sport specific training!
Low back pain/injuries is the injury I see most with young athletes. Other injuries related to the core are also a big problem with young athletes. Many times, its related to lack of core training.
Even injuries that seem to be unrelated to the core, can originate with the core. For example, I have a friend who had a serious elbow and forearm injury. The cause of the injury was out-of-line shoulder blades. This caused his throwing motion to be flawed and it lead to his elbow/foreman injury. After months of rehab, he is back to about 85% but still not ready to pitch again in the minor leagues.
Young athletes need careful monitoring to make sure they are doing the exercises correctly. Don't skip the core training! That's why I only do 1-on-1 training for all clients. Core strength exercises should be emphasized first and not the highly glamourized plyometric training. Plyometrics should be introduced when the athlete has advanced to a level that allows she or he to handle this high level of training. I have seen more than one athlete with injuries because of inadequate core strength.
Foundational stability strength is critical for young athletes!