Tango, why is there a choice? What I mean is, if the goal is to simply "hide the ball" then ok. But if the goal is to hide the ball and use it as part of the motion/delivery, she SHOULD ultimately get even more power. I've said this on many video clips on both authorized and pirated on YouTube, and in my DVD's.. but, ONE of the major problems with swinging the arm back is, the glove hand in 99% of the cases stops at the legs and isn't used. So, swinging one arm back means, only one arm is going to be used to thrust off the rubber and deliver the pitch. Meanwhile, the glove hand does nothing to help with the arms leading the way in the thrust from the rubber. Think of it this way: if I said, stand still and broad jump as far forward as you can, would you swing only 1 arm back for momentum or both? (Hopefully you said both). So, it's the same principal. If she can swing both hands back (in many cases with ball in the glove) then she will push forward with BOTH hands leading the way. But, if she swings only 1 arm back, then she's only going to swing 1 arm forward. Personally, when I pitched at the height of my career, my hands came together at my side to hide the ball from the prying eyes of 3rd base coaches and 3rd base dugouts, then with the ball INSIDE my glove, I would swing both hands backward (in a negative motion) in order to get a much stronger POSITIVE motion as I would "shove the glove" towards the target. While the timing takes some getting used to, ultimately she will throw harder using both halves of her body pushing outward instead of only one arm swinging outward. On top of that, she will not only "hide the ball" but, she'll get more power from both halves, give a better chance of NOT locking her elbow during the backswing, AND drastically cut down the chances of the glove hand swimming... because the longer the ball/hand stays in the glove, the less chance it has to fly out and swim.
In my experience, pitchers who throw "harder" with the back arm swing are doing so because they're using muscle. The OVERWHELMING majority of girls who do this will tell you, if they're honest, that they get sore in the front of their shoulder from the tension and overuse of muscling the pitch. And lets be honest, no 12-14 year old should be sore from pitching!!! Sore means something is being overused. The girls who don't do this, MOST OF THE TIME, can pitch longer, more consecutive games, etc. because they're using their entire body, not the muscle in the shoulder to deliver the pitch.
I know there will be people who point to "Jane Doe" and say, she can pitch all day with a back arm swing, etc. Fine, there are always exceptions that prove the rule. But many of those exceptions are like Jennie Finch, Monica Abbott, etc. and stand 6'2 with long leverage, and dare I say it, are good not BECAUSE of what they do but despite of it.
Bill
Thanks coach, we bought your DVD's and have used them to really help my DD before ever seeing a PC. She doesn't swing back but has started kinda dangling the ball beside her hip. We started back working on keeping the ball in her glove and pushing her hands toward the target but she lost a little speed.