We took DD to a sports trainer.. He trains track athletes and it has made a big difference for DD. We told him heavy on the core. He understands pitching and has her doing explosive type exercises. I haven't been to the gym in a few weeks to see her train. Thursday I stopped by and she is doing full pistol squats. 7 months ago she couldn't even do the first step in that exercise. She also had very bad back pain due to an undeveloped core. That has since been strengthened and the pain is gone! Devote as much time and resources to training your DD as you do to having her pitch!