Pick any profession. I bet if you were to watch someone at the top level in any field, you would be likely to learn something useful that you haven’t even realized you didn’t know. The way they talk, the way they walk, the way they handle themselves and the environment. Jedi masters of the world give the impression that they have been there, they have done that. “Oh, don’t bother trying that. I did that in 97. I didn’t work. But you might try this.” The best way to learn is by trial and error. No one said that the errors have to be your own.
Recently, I have been studying movement patterns. The work of Kelly Starret stands both in comprehensiveness and clarity. He brakes various exercises into so-called body archetypes. You can decompose each movement, no matter how complex, into a collection of patterns. And the same patterns repeat over and over again in various sports. This results from the fact human joints operate most efficiently in only one plane. If you deviate from the optimal plane of motion, you exert excessive stresses on the joint surface and risk the injury. The stress magnitude is inversely proportional to the area of a contact surface between bones. Thus, the stresses are the lowest, when the contact area is the greatest. The maximum contact surface area corresponds to the optimal plane of motion.
If you perform an exercise sloppily, the excessive stresses will break the cartilage. It takes up to seven days for cartilage tissue to heal. The symptoms include the feeling of swollen joints and a heating sensation. The interesting fact is that the cardiovascular system doesn’t supply cartilage tissue with nutrients. Cartilage responds best to low-intensity movement like walking. Mild physical activity causes circulation of synovial fluid which in turn delivers nutrients into the cartilage.