Our work with elite athletes serves as the proving grounds for our methods. Most people don’t play professional sports. But if our methods help athletes at the highest levels, they can work for anyone.
That’s a tough issue to work through. All the videos that Kaitlin linked are perfect. I would also tell you can have adaptations at certain joints with high volumes of training at early ages. For instance, I work with a decent amount of baseball players that lack full elbow extension and full IR on their throwing arm. This is due to increased bone development in the elbow from years and years of throwing. This isn’t necessarily a big deal in their sport but when they try and do an overhead squat it kills them because they can’t lock out. If you work on this and realize that you aren’t making any improvements you may want to try and focus on the shoulder. The better your shoulder and upper back mobility is the more narrow of a position you can adopt on things like overhead squats/squat snatches.