Yeah, I ask way too many questions. Anyhow, I was reading on prosthetic legs and I noticed that one runner said he had to run on the balls of his feet with the prosthesis on. Having done this and suffered tendinitis due to too much tension when running, I thought about trying to make a prosthetic leg that tries to act as more of a shock absorber, to sort of relieve the pressure and make it easier to run and lower chances of injury. This is what i was thinking of http://img40.imageshack.us/img40/2817/p7190652.jpg [Broken] Possibly minus the bottom low spring constant springs. I was thinking of making it for the experience, try to get a better understanding of mechanics. Essentially, the top part is stuck in the bottom part because of the triangles on the side. It rests on a high tension spring, so that the spring absorbs some of the shock from landing, but doesn't fold in. Any advice on this? If it comes to anything I might try entering it in a science fair, but I'm not sure. Mainly I want the experience, so thanks for any advice!