Just my opinion….
Overusing a catcher is more of just “wearing him out” rather than doing damage to his body. The way a catcher uses his legs is very different that the way a pitcher uses his arm. A great amount of damaging force is being put on a pitcher’s arm when he pitches whereas muscle fatigue is the culprit of the catcher. I feel as if knee problems aren’t necessarily the result of catching but I’m sure if there is a problem with the knees it would be aggravated by the continual flexing of the knee. Knee savers do distribute the weight more evenly and allow the catcher to “relax” his muscles and joints more while squatting. When my son first started catching he would have soreness in the groin, legs, and knees, but only because his body was not conditioned. The more he caught the better his legs felt. Keeping the body hydrated is also important. Catchers’ bodies lose a tremendous amount of fluids while catching which will lead to muscle cramps and soreness. So how much is too much? In my opinion a catcher in “game shape”, even a pre-high schooler, should be able to catch a game a day without any problems...but...a double header behind the plate, especially in hot weather, is asking too much from a kid.
Fungo