By James R. Andrews, MD
Baseball is our American pastime and it has always been expected to be a safe and healthy sport. However since 2000, there has been a five- to seven-fold increase in youth baseball injuries. Injuries now have approached epidemic proportions. Moreover, many of the arm injuries of professional baseball pitchers have been documented to have had their origins at the youth level.
One of the missions of the USA Baseball Medical Safety & Advisory Committee has been to provide scientifically based information to its youth baseball members to reduce the risk of injury and maximize younger players’ abilities to perform at advanced to higher levels. Because of this support of USA Baseball, we at the American Sports Medicine Institute (ASMI) began to research the epidemic. 
Fatigue and joint pain
A major risk factor associated with injuries in youth baseball is excessive pitch counts. Research from ASMI indicates that if a youth baseball player pitches with fatigue, then there is a 36 to 1 times (3,600% increase) chance that he or she will injure their throwing shoulder and/or elbow. Pitching with fatigue means “event fatigue,” which is too many pitches in a game; “seasonal fatigue,” which is too many innings in a season; and “year-round fatigue,” which is too many innings year-round without rest. We have always recommended that a young thrower have at least 2 months, preferably 3 to 4 months, off each year where he or she is not participating in an overhead throwing sport.