The concept is as you hint, very much one of continued leverage to prevent reverse movement with constant micro gains in forward distance.
Very much a parallel process with the same kind of force multiplication as any gear ratio mechanical advantage. Quite marvelous what the simple ability to "stick" can be translated into. Tremendous static holds equals tremendous kinetic force :-)
I'm pretty sure that our quadriceps could lift a one-ton weight, if attached to it, if only a few cm. That's amazing to me.