Your comments and article are accepted but I am not sure if you grasped my point.
More specifically, I am interested in looking at my efficiency factor when -
- I am doing an 0.5 - 1.5 hr TR indoor workout (which I have repeated many times)
- On my bike which has a static set up
I also tend to eat & drink the same things during those workouts so most of the variables above arent really variables, and the ones that are variables are most definitely of interest (eg level of recovery and lingering illness) to my performance on the bike.
My point was that efficency factor is a good metric to bear in mind considering the other variables you mentioned as it is a “measure of aerobic efficiency specifically on low intensity aerobic rides” Joe Friel also provides more detailed reasons for this metric in the “Power Meter Handbook” which is worth a read.
So personally after 4 years of TR rides training with power and just under 1400 rides on trainerroad, I have started looking at power efficiency on workouts I have repeated many times over several seasons. Please note this isnt a big data exercise its just me logging and looking at my rides on excel. From my data, efficiency factor appears to give me a good indication of my condition at that point in time which work with the FTP tests as these are only done every 4-6 weeks on most TR plans. I assume Joe Friel also found it of use during coaching as he has included it with training peaks as a metric.
Normalised power isnt a good metric to measure your condition on a base level ride if heart rate isnt included because of the variables you mentioned above. For example, caffeine and my motivation level will increase normalised power but they also increase heart rate accordingly so dont seem to impact efficiency factor. Recovery from illness or too much TSS will drop my normalised power relative to heart rate so will reduce efficiency factor.
So for example Nates efficiency factor on Baxter (a workout he repeats many times) would give him a good measure of his condition at that point in time and an indication of the success of any experiment he was running to try and improve his performance. In my experience it would also give him an indication of whether he was due an uplift or reduction in FTP at his next test.
Anyway that was my point on efficiency factor but if you want more details on the metric have a look at Friels book or Training peaks etc.
One final comment linked in with efficiency factor is that although the TR software is excellent, one issue is that it has no ongoing measure of an athletes current (daily) condition. A TR rider may need to back off training if they are coming down or recovering from illness, have too much TSS or an experiment on nutrition isnt working etc. Therefore the athlete has to find a way to evaluate their condition (perhaps by measure resting heart rate, heart rate variability, qualitative feeling or efficiency factor on a ride) to know when to back off or ramp up training. Effectively the TR rider has to self coach in these areas as there is no TR metric for guidance.
However, I did notice Training peaks has started to link with heart rate variability software. My experience to date measuring heart rate variability is that it is a bit hit and miss as it often appears to me to be a lagging rather than a leading indicator. HRV and the best ways to self evaluate condition during training between FTP tests could probably make a good podcast topic by the way.
Anyway keep up the good work.