I have had 9 catching related knee surgeries. I have a replaced knee that got done when I was 43. I played before the knee savers came around. I see them as a terrible idea. My son is a soph catcher and has caught his whole life. I would never let him wear them. I never let the kids I've coached wear them. My reasons have nothing to do with blocking, resting, getting lazy, high target, etc. I'm no doctor but sitting down on a wedge between the back of your thigh and the top of your calf has to put a strain on the front part of your knee, In science terms, a wedge is piece of material used to separate or split objects apart. Sitting on a wedge has to put extra pressure on your ligaments to keep your knee tight. The other possibility that I think of is a slight separation in the knee joint (spreading apart) that would create a greater chance for cartilage damage. I may be wrong, but I've spent many a day behind the ol dish. I have lots of scars to prove it. Have a good weekend everyone! Hit 'em where they aint!