It's often been said that arm strength is something one is born with and cannot be really improved upon but, over the past few years I've seen a few QBs that have improved their arm strength dramatically after the offseason. Velocity, deep ball, deep ball accuracy, and all just seemed to improve. One example is Kyle Orton, if you look at his tape from the 2009 season, he really couldn't stretch the field and he had a horrendous deep ball, the offense was pretty much based upon what the receivers could do after the catch and not really vertical routes. this year he was throwing all over defenses and looked to have a lot more zip on his passes plus his deep ball was actually pretty decent. He also credited his better performances to some off season training program he did that helped improve his arm strength. My question is.... If arm strength can be somewhat serviced what is stopping teams from grabbing up QBs that are very smart, accurate passers but, don't really have the best arm strength(Ponder &Mcelroy)?