Hi All, It’s been a while since my last post. Very busy lately. Chandler I agree with Roger, Because you lack early momentum, you stall over the rubber never getting the lower half going. Something else I see as well and that is your drive leg foot position on the rubber. When you place half of your foot on the rubber, it causes you to turn your knee in causing early rotation. This is why you stall over the rubber, tilt your upper body back, and only push your hip out at hand break. You do not use ground force correctly to get you driving down the mound.The whole purpose of leading with the hips is to create early momentum in the leg/load phase of the delivery. That momentum is then used to assist a powerful back leg drive, which is then converted to explosive rotational power. Where does this all start, your bottom foot.
Think of it this way, If you put a force plate under your back foot, just in front of the rubber you would want to generate the largest, most sustainable ground reaction force possible under your back leg. When a pitcher uses only their heel, the ball of their foot, or in your case putting pressure on the inside of your foot, you can not generate the ground force necessary to drive properly down the mound. I teach my pitchers to use their entire foot. When you use the mound as you do, it causes internal rotation of the knee (your knee should be in a vertical position) and poor head tilt (your chin should be over your bellybutton). Look at Marcus Stroman at hand break. Notice his bottom foot, vertical knee, sitting into his drive, and head over bellybutton.