actually i think weight training helps tremendously for pitchers. See Billy Wagner and his legs...yes i think its fine for their arms as well from what I have seen. Guys dont lose their flexibility as once believed....unless they are on the juice and have some abnormal size muscles for their frame and not too many pitchers have that. They need a solid base ... look at fat Bartolo Colon... very durable. Same with David Wells before his back problems. What about CC Sabbathia? lol i think pitchers who work out their upper bodies as well as lower with above average (lifting) weight do just fine. Its the smaller ones who seem to break down that don't throw everyday all day like we did when we were growing up...but i am not medical expert.