“I love pitching but struggle to throw fast.”
This means you are normal! You fall in the median range for all people.
The way Velo works is completely genetic with any mechanics you employ.
It’s the percentage difference between Fast twitch (type2) muscle fiber and slow twitch (type1) muscle fiber that dictates how fast you move in any compounded Kinetic chain. We can improve it just slightly by mechanical manipulations and sport specific fitness.
“I know there must have a separation between hips and shoulders.”
Only if performed after the Humerus is fully outwardly rotated and ready to throw!
If you perform hip/shoulder separation while your arm is not ready to throw (inwardly rotated at the back) it is wasted (shortening the muscles that you previously separated) into transitioning your Humerus and not used to forwardly throw like in all traditional throwers and pitchers.
“Are all “floors” (or segments, maybe a better term) rotating “actively” or some are “passive” ? When I’m talking with these terms, I want to say “forcefully rotated” (active) and rotated by the previous segment (passive).”
It’s both, voluntary conscious rotation is how you should practice. When competition starts, it’s proprioceptive performed without a thought of it.
“Some people talk of pushing against the rubber (the “King of the hill” tool seems to be OK with that) and some say to not do It.”
Most pitching coaches do it because they love it, not because they are experts in Kinesiology, in fact Kinesiologists are degraded by all who coach because it is threatening to them when an actual expert tells them they have had it wrong from the start.
With the traditional approach, nothing is gained in forwards momentum if the ball is not also simultaneously making forwards movement. Pushing hard of the rubber is a waste of effort and perturbs the lengthening process. All forwards momentum from falling or pushing in is halted by a complete stop in forwards momentum when the glove leg plants because the Humerus is still inwardly rotated, you are still at 0 velo.
“Here we do not really have pitching coaches “
This puts you in an advanced situation. We also do not have pitching coaches. We have pushers of past info still trying to justify a pathomechanical force application.
“it’s very difficult to have a real teaching of basics mechanics behind pitching.”
Touche, here also. Like I said, here everybody is not an expert and are on a guessing tour that results in novice explanations that become alternative facts.
“Is it possible to help me please ?”
You will only see gains up to your genetic potential unfortunately! This does not mean you can not enjoy pitching in competitive games or improve a little in Velo. You are not in the MLB, so get off of that thinking and go enjoy!
“Consider you explain pitching mechanics to a child”
Go to Dr. Mike Marshall and read that information, this is what I have all my clients and their parents do first. By the way, the children all understand it if taught, it is only the adults that have problems.
Don’t worry that he recommends not lifting your leg! You can still uselessly lift your leg if you want to, so you can look like all the rest, but it will not help you in any way.
Any question feel free to ask.