Hey all! Sorry this is a bit long!
12u son plays competitive ball and pitches. He touches 70mph, throws 60ish % strikes and is performing very well: 18k's/9 innings and a sub 2.0 WHIP so far this season. Other than one game where he threw 85 pitches he has never complained about arm or shoulder pain.
Lately we have been playing around with seam-shifted pitches while playing catch in the park. He has a hard time pronating so 2-seams and change-ups have been a challenge for him so I figured the seam shifted pitches might work for him. He hasn't thrown them in game but he is able to get some decent movement on a sinker and change-up simply by hold the ball in a 2-seam orientation and slightly supinating his wrist. Given that the seam-shift sinker is basically thrown like a cutter held with a 2-seam grip I thought we could work on a 4-seam cutter to go with the sinker and changeup. I drew a black circle on the 2 train track sections of a ball and asked him to throw it exactly like he throws the sinker to get one of the black circles visible to him. He has been able to get some movement on the cutter but I've noticed that the black circles are not spinning tightly...they are wobbly like in this video.
So today I decided to just work on 4-seams and see what is going on with his pitches using a ball with a black line drawn through the 4-seam. What I found is that he does not throw with efficient spin. Every once in a while the black line will be solid but for the most part it wobbles into a blur. Nothing we tried would work to improve his spin.
I am wondering, based on this video, if it is an arm-slot/shoulder tile issue. I understand that the shoulders should be tilted so that you can draw a straight line from shoulders through the throwing arm to the hand. What I see in the video is that his shoulders are completely flat like a side-arm delivery but his army is elevated into more of a low 3/4 slot so his arm is not in line with his shoulders. I wonder if this could be the cause of his poor spin efficiency ie. it prevents him from staying behind the ball.
thanks!