Originally Posted by
Carbonfiberboy
Here's the problem with that:
The efficiency of a system is related to the energy input and the useful energy output.
The definition of efficiency is In the case of a cyclist, it's food energy in vs. kilojoules output at the pedals. It should be obvious that pedaling style doesn't change this ratio (much). However, it should be noted that it's possible due to internal friction of our muscles that using more muscles might very slightly reduce this measure of efficiency. This is what fuels the ridiculous flats vs. clips debate as to efficiency.
In another way of looking at efficiency, we could say that mph is the output and watts at the pedals in the input. Again it should be obvious that pedaling style doesn't influence how fast we go compared to what our watt meter says. However bike position and touring load certainly does.
You are trying to separate that which can't be separated. If, at the end of the day, you have used less muscle energy as measured by muscle fatigue, then your energy efficiency...i.e. your energy output to energy input...is greater. The extra internal friction of the muscles from
not using clipless is still part of that energy balance.
Energy lost as friction is still energy that is input into the system without getting energy output. In other words, wasted energy and decrease efficiency.