All of the weight is on your calf and thigh muscles. The knees will hurt from time to time but after years of doing it and working out, you just learn to play through the pain. Catchers do a lot of leg work outs and have extremely muscular legs. Technique is not as much of a factor in comfort on the legs. The Technique comes into play with blocking balls, throwing the ball (especially when trying to throw runners out), catching the ball itself, and moving around. Catchers do a lot of leg work outs and have extremely muscular legs.
You have to be really durable to be a catcher. They go through plenty of pain in their knees throughout the season. They just take good care of themselves.
with everything that everyone else said they are in great shape. and sometimes the catchers have pads on the back of their legs to sit on. but that is not necessarily the case all of the time. i might be wrong.
First, they don't sit, they crouch. Second, they don't crouch all the way down, at least not all the time. Third, they position their legs and feet so everything is in line. Fourth, they're in really good shape.
So, technique counts.
These guys are in great shape - you might just be unfit (and I'm not judging because I can't do it either).
I tried to sit like a baseball catcher for 30 seconds and my knees hurt really badly.
