Biomechanics question: most efficient way to mount steps?

Question

What is the most efficient way to walk up steps under your own power? By efficient I mean creating the least stress on the knee and least muscle exertion. I assume no use of hand rails or walking devices. I have had knee surgery, and have "discovered" two ways of walking up steps. One is the "normal" (plant and lift). The other I couldn't describe, but it has to do with more hinge-ing motion in the knee, and feels less strenuous. This is why I ask the question in these terms. I should think robotics researchers might have considered this, as well as physical therapists.

Answer 1

Having had knee surgery myself I suspect what you have found is that if the knee is "locked" so the movement action is pivoting at the hip, it puts less strain on the knee. It requires that the body be moving at roughly the angle of the stairs and have enough momentum so that when the foot hits a step, the body "rides" up and over on the lever formed by the leg (like an old fashioned pole vaulter before the poles became so springy.) The problem is that while this works great on curbs and 2-3 step rises, it is very hard to maintain velocity up more steps and the lifting process takes over.
It also requires considerable eye-leg coordination, which makes it really tricky to carry out with a robot, most of which like to keep something planted firmly while moving the lifting method.`