I've been a runner and hiker for many years, and have known that one leg was longer than the other. Gradually, this has lead to pain and injury in my back, hip, and foot on the longer side, and kept me from pushing my limits as a runner. Now that I am experimenting with American Heeler's lifts, the back pain is improving, as are the other pains. If you also have symptoms like mine -- back pain and pain in one hip/foot and you think it is because of a difference in leg length, give this a try.