A recent study in the American Journal of Sports Medicine suggests that young pitchers (boys, age 9-14) pitching more than 100 innings per year are at significantly higher risk of serious injury. It is important for parents and coaches to keep in mind always the delicate balance between improving strength and skills, on the one hand, and potentially career ending injuries on the other.

Here is the link for anyone who want to read more: http://ajs.sagepub.com/content/39/2/253