What is a good Efficiency Factor range?


I understand that Efficiency Factor is a ratio of internal (HR) load to external (power, speed) load, but what is the range of ratio that I should be aiming for? 1:1 or something else?

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@Prof Got a study for this question?

You want to be aiming to improve your own personal efficiency factor baseline. Just like heart rate ranges vary so does EF baselines. The higher your personal baseline the better, as for cycling it means you are putting out more power for the same heart rate. If your EF was 1:1 then at 200 bpm you’re putting out 200 watts, which would be limiting in terms of where you could go if 1:1 were optimal.

I’ve read (I think) that pro cyclist EFs are in the 2:1 ratio (maybe more)?


I have been monitoring my Efficiency Factor closely after returning to training after 9 months of inactivity. I am so far off my previous fitness progress has been slow , but I can see the EF slowly tick upward. It has been a useful motivational tool.
I can put in a hard run and kid myself my fitness is back, but you can’t force the EF, it tells the truth!

I suspect it is a good reflection of performance potential but a lot of individuality with actual value.


I’ll echo what the boys above have already said here.

Efficiency is your external output (watts or normalized grade pace) / internal effort (Heart rate) . If you can run with less internal effort (lower heart rate) at same speed as previously, then you are getting more efficient. You’re getting more efficient in your running / bicycling as you are putting out the same external output but with less internal effort.

Say for example that you have done your 5K TT run (or FTP) test with Athletica. Let’s throw in some random numbers:

  1. 22mins with average HR of 165.
  2. 225w with average HR of 155.
    If you go your merry way and train well (not overdoing it), and re-do the same tests after a few months, and your numbers are:
  3. 21:45 with average HR of 160 (you’ve incresed your EF)
  4. 225w with average of 150 (you’ve increased your EF)

BTW. arbitrary numbers but you get the point.
The point is to compare the same workouts over time, as obviously running on a hilly course would affect your internal effort (and your external output).

As you get fitter, you’re EF will rise.
Maybe it’s not this clear and simple, but I am sure @prof will chime in.


I think that was an excellent arbitrary example!