Thank you for the tips! Her injury was to her hip on her front leg side caused by her landing straight legged. She felt the pain in her lower back on that side. She only felt it when she landed. 6 mos no pitching, chiropractors and physical therapy got her back. Then we worked with Stephanie Beane to "soften" the landing thus triggering front side resistance. Her speed was improving but lately I noticed it's declining. She may be falling into previous bad habits. I'll definitely look at some slo mo videos because I do believe she's opening early. Thank you for the suggestion on what to look for!Maybe you already learned this, but that back foot isn't the cause. It's the symptom. Insufficient drive mechanics is the culprit. Typically, the back leg is down because the body is lagging. You'll likely notice the front foot leg below the knee is pretty much vertical at the time she lands.
When things are correct, you'll see that front leg come down in an arc. That means she's still moving forward at the time she plants, which will trigger that front side resistance. If you see that landing correct, you'll see that back foot mostly or completely on the toe. That loss of momentum caused by the insufficient drive causes everything to drop. Front leg collapses and she has to plant, squat, and restabilize, which you'll usually see manifested in her springing UP and extend the leg right at the piont of release. ZOOM. High pitch. Some girls compensate well or manage to get rid of the ball before they spring back up, but there's speed and stability loss there. A lot of times the bad front side resistance throwers will fall to the right as well. Posture and stability are very compromised.
A good way to see how things are progressing is to take slo-mo video and check the drive leg when her arm is at the 3:00 position. Ideally, her body is still moving straight out, and that back leg is all or mostly extended, and there is no load on it. The toe should be just starting to turn over onto the top side of the shoe. If she's an early opener, you'll still want to see if there's any weight remaining on that drive foot despite it being or starting to be sideways.