I want to get opinions on a particular exercise the high school had my son doing in upper body workouts. He is 15 years old and had pitched on Saturday and Sunday in a tournament for a total of 8 innings. Two days later they were doing an exercise involving 5 pound weights in each hand and jumping up and down. As you go up you extend your shoulder and elbows over your head and as you come down your arms come back down with the elbows in the flexed position. The exercise is repeated quickly for whatever number of reps you are doing. In this case it was 30. The issue is that while he had no shoulder pain or history of prior to this, he now has pain in his throwing shoulder and can't pitch.