#258--Most leg length discrepancies are FUNCTIONAL rather than MECHANICAL. That is, the leg appears different in length due to the effects of either weak muscles or strong muscles. For example, a weak glute medius on the right side will allow the pelvis to deviate to the right and elevate the right hip. This gives the impression of a shorter left leg. Yet this same person could lie down and the right leg would appear shorter due to the pull of the lateral abdominal muscles. Either way, the faulty posture is not driven by the bones and, thus, is not mechanical in origin. So putting a lift in the shoe "fix" the problem may actually just perpetuate the problem. Addressed in this fashion, the lift could actually contribute to a permanent shortening of the leg in question as muscles held in a shortened position will drop sarcomeres and be more difficult to return to their normal resting length. So if a doctor tells you that you have a leg length discrepancy, pass on the lift suggestion and stretch the tight muscles acting on the leg and pelvis, and strengthen the weak ones.