RChung

Bingo. This is what @asgelle was getting at. The only way to measure efficiency is by measuring what goes in and what comes out, and most of us have never actually had that measured: but when it does get measured, it appears that we optimize over something else entirely. The bottom line is that we should almost always avoid the use of the term "efficient" as a justification for what we do when we ride. This is particularly true for cadence but also about claims of "efficient" pedaling technique. When we ride, freely-choosing cadence or crank torque or work rate, we're optimizing something but it ain't efficiency -- and that's okay.