You know, it occurred to to me that the OP could answer performance related questions such as the one in this thread, and the one in the Low gear or stand up thread, for himself. All it would take is a cycling ergometer that measured power and heartrate. Such ergometers, such as those of the Lifecycle brand, are commonly found in gyms and health clubs.

In both questions the heart of the question is efficiency: the amount of useful work done relative to the amount of energy required to perform it. An ergometer measures the useful work performed directly, and heartrate is an indicator of the energy required to perform it. So, the experiment to evaluate foot position might go as follows:

1) Warm up for ten minutes or so

2) Start using foot position A, set the resistance and control cadence to achieve a steady power output of 150 Watts. (The subject should pick a power level that they can sustain comfortably for the duration of the experiment.)

3) Start recording heart rate every minute

4) Ride for 30 minutes using foot postion A.

Save the recorded heart rate and power level set point.

5) On another day perform the same experiment, using the same power level set point, and making the same heart rate recordings using foot position B.

6) Repeat A and B sessions on several days across several weeks

The foot position that results in the lower average heart rate is the more efficient one.

Speedo