There a lot of people who’ve dubbed themselves “gurus” in the realm of pitching mechanics. Most of these people are just guys who have an opinion, a website, and great marketing (which lies in false promises). Not everything they say is incorrect but for the most part their philosophies do more harm then good.
One of the self-proclaimed pitching gurus is Dr. Mike Marshall. He had a mediocre career in the Major Leagues and then got his doctorate in kinesiology. Some of what Marshall says is correct. For instance he is a major proponent of pronation. But for the most part it ends there. Even his philosophy on pronation is pretty far from anything remotely called pitching. I just want to warn you against Marshall’s philosophy and those who teach it. I could spot off for days but I think nothing works better than showing you a video of how Mike Marshall wants you to throw. If you agree with this video, please come see me.
You all know I’m student of Ron Wolforth, so I listen to what he says and I have a bias towards his philosphies. The difference between Ron and most others is that every 3 months he throws out everything and recreates his program. He is not afraid to throw away an exercise or idea if it has been proven wrong, or if it is not supported. I think he’s come the closest to understanding the complex, complex biomechanical action that is pitching. That said, I don’t agree with everything he teaches.
You should do the same. Seek out mechanical advice and listen to the reasoning, but then scrutinize it harshly. If it stands up to that then add it to your own program. Then 3 months later, review everything and see if it all still stands up.