Originally Posted by Squirrelfighter
Yeah, its pretty common among baseball catchers. Some have to have several knee surgeries during their career as a stop-gap to minimize the process that wears away at the cartillage until eventually there's none left.
Ah, ok, I've googled some pictures and I think the difference is that Asian people squat flat footed like little kids do, while baseball catchers squat rather on the balls of their feet, probably to be more agile while catching the ball. So Asian people basically "hang down" from their lower legs with their knees almost above their feet and no tension on the femoral muscles which they don't need as for them it's a very stational position and baseball catchers rather sit "on" their lower legs with a lot of tension in their femoral muscles and their knees before their feet which combined puts a lot of pressure on the knees.