A cyclist will have the pedal spindle somewhere under the front part of their foot, usually around or just behind the ball of the foot. This means that the ankle is part of the driving movement - at a minimum, holding itself in a single position while the other muscles apply torque to the pedals, so the 'ankle muscles' are acting as a static stabilising force; or in some riders the ankle position changes throughout the pedal stroke, possibly helping to apply force around more of the pedal circle, possibly helping around the 'dead spots' where the pedals are at the 12 and 6 o'clock positions. This video illustrates it very well, from 3m08s: https://www.youtube.com/watch?v=E7K8VcBXUM4#t=3m08s
Are there any machines designed to utilise a similar mechanism? Off the top of my head something like a steam train doesn't, it uses the fewest, simplest parts to enable the linear movement of a piston to be translated to the circular movement of the wheels.
What would be the advantages/disadvantages of such a mechanical setup?