People who can jump high and run fast generally will have strong legs, minimal body fat, and good technique. Not to mention extra tendons......
Yeah, I hate those people with extra tendons. I tried buying some off ebay and I don't recommend the ones you are supposed to install yourself. Now, extra ligaments or bones, that is crazy. Never start a fight with a guy who has 207 bones. Big mistake.
Yeah, I can standing dunk because I have four hamstrings. What, you were born with just one? Sucks for you.