Here is a video of my son James pitching. He is 12 years old…
If you have a video at normal speed it would be easier to analyze. One of the first thing I look at is a pitchers overall rhythm and tempo. I look to see if it is fluid and smooth or stiff/mechanical and slow. Very hard to tell in slo motion.
Second thing I look at is early momentum. Is there early weight shift while getting gathered and loaded. In your sons case, no. What I look for is a pitcher generating ground force and using that ground force to start moving his core down the mound before hand break. In other words his center of gravity and hips should lead the delivery. At hand break, your son gets stuck over his back foot.
I would suggest working on drills to help create early momentum towards his target. I like to see my pitchers accelerate into pitch release with a powerful back leg drive. Your back leg including your back foot also has a big impact on your direction and control.
There are some other small issues I see as well like opening up too early, but I would work on early momentum out of hand break first. I really do like his finish. Nice forward trunk tilt, good stable landing foot, and hip rotation.
I included some images below so you can visually see what I am talking about
Steve thanks so much! Really appreciate your time. Here is the motion at regular speed. Really appreciate any feedback you can give at this speed. Thanks again!
I can see a lot more at regular speed. What I did was loop the video and watched it over and over. One of the biggest issues I see with pitchers is a tendency to move too slowly in their deliveries especially in the beginning of the delivery at leg lift and hand separation. When a pitcher moves too slowly and more deliberately or stiff and mechanical, not only does the pitcher lose momentum and power, but it makes it more difficult to pitch with good timing and rhythm in their delivery.
That is what I noticed with James. His timing and rhythm are are slower in the beginning of his delivery (weight over his back foot) at leg lift and hand break because of a lack of early momentum at leg lift. What I like to see is a pitcher starting to shift his front hip away from the rubber prior to hand break using ground force while his support knee stays over his support foot. When you throw off this timing portion of the delivery you throw off the timing of the kinetic chain. When the kinetic chain timing is off then arm action and hip/shoulder separation are off as well.
Good new is, there are many drills James can do to help him gain early weight shift. And, if you are like the part of the country I live in, all sports have shut down because of the CoronaVirus. Now would be a great time to practice forward momentum before hand break. Some of the drills I like to get a pitcher moving prior to hand break is the Wall Drill, Rocker Drill, and Step Behinds. Take a look at the video below. I pared my son with your son. You can see how much work was put in to get my son to this point.
I agree with Steve - too slow into front foot strike. Put a stopwatch on him and time him from first movement to front foot strike. Ideally you want him around 0.95 seconds.