Arm strength

Arm strength can be built on field through a managed long toss program. Off the field my son has had success with the Throwers Ten exercises, a series of band and very light weight exercises designed to build and maintain shoulder strength in pitchers, but would apply to all. Google Throwers Ten and you can download the routine. Key to this is light weight, 2 - 4 lb dumbells, and repetition. Start at lighter weight.

+1 on throwers 10. My son had some arm soreness a few years ago. Pysical therapist put him thru throwers 10. End result was a nice increase in strength and no more pain. Nice thing is that it can be done indoors during the winter.

This fall as long as you can get outside, I would consider a long toss program as well. Good luck.

Realistically, the thing that will increase his strength most is just getting older and bigger. Of course there is benefit to a throwing and conditioning program - although it should be something that focuses on injury prevention more than just increasing velocity.

I would say at your son's age that you should focus more on accuracy and good transfer mechanics. Take the focus away from the pop time and put it on catch to release time while using proper mechanics. Work on the things that can be corrected, and let nature work on increasing velocity.

Remember also that a 2.9 on the bag is better than a 2.6 to a bad spot.