I need a new bag.

[Sithdarth]

Again, I'm speaking long term. We aren't talking 25lbs on a joint, we aren't even talking 255lbs on a joint, we are talking about taking your current load bearing responsibilities and multiplying it with the force of gravity.

Running up the stairs? I'm cool with that, you are lifting basically 255lbs and the joint CAN deal with that, but running down the stairs will amplify that force, the quicker you go the faster repetition on the joints so it's still going to wear.

I'm talking about not having knee replacements when you hit 45-60, and saving a lot of aches up until then.

Yeah you see this right there its a load of crap. It takes exactly as much force to lift something as it does to keep it from falling. There is no amplifying effect here. I mean if you hit the stairs straight legged and don't do anything at all to absorb the impact then you can stress the joint. However, if you bend through the same distance when you step down as when you step up the stresses are identical. Things aren't magically heavier because they are going downwards. It takes exactly as much energy to lift something up one stair as it does to stop something that has fallen the distance of one stair. If you also spread the stop over the same distance as the lift the forces encountered are absolutely identical. That's how physics works. Anybody that insists the landing part of a jump is any harder than the jumping part on your body is simply landing wrong and not taking full advantage of their limbs or the physics involved.

Beyond that human joints where never meant to last 45 years. They certainly weren't meant to last 60. I might as well make use of my knees while I have them instead of waiting for them to deteriorate on their own. Besides it's not like I'm not taking preventive measures or anything. Karate and any other hard martial art is tough on the joints so I've been taking joint supplements for awhile. I'm not saying I'm not worried about the future I'm saying I'll deal with it when the time comes. If my knees hurt then they hurt. Pain never killed anyone. I actually fell off the back of the truck and banged one of my knees pretty good. That was years ago and the doctor said there was no sign of one of the ligaments that runs down the back of the knee when they took the MRI. You know what his advice was? You'll be fine without it just strengthen the muscles around the knee and they'll compensate for it and the pain will go away. You know what happened? I worked like crazy and strengthened my knees and now they are better than ever and no pain. I think I'll trust medical science and physics. I know how to take the stress off my knees by using my foot first then my whole leg to absorb and dissipate the shock, I do this running barefoot, so that I feel more stress on the way up the stairs than the way down the stairs.