strengthening her core
As you all know there is no magic pill to pick up 3-4 MPH. Only hard work and effort. If mechanics are good then make them great. If legs are weak then make them strong. I disagree with the statement that core strength doesn't help speed. While it may not directly correlate if a girl has a weak core she will get injured pushing to 100% over and over. Happened to my kid.
Long toss, strength and conditioning training, running, max pitches, drills you name it. They all help but like anything you have to do them long enough to see results and like many of us who try to quit smoking, etc.. human tendency is to stop right before the breakthrough takes place.
Not sure we're thinking the same here Gunner...There is no correlation between core strength and pitch velocity.