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Can someone explain EF "efficiency factor" in TP in English?
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I'm looking at the EF calculation of some of my recent runs and don't understand the formula for coming up with this number, nor exactly what it means, nor a "scale" to compare similar to power / FTP / w:kg. I read the paper in TP http://home.trainingpeaks.com/...actor-and-decoupling and still don't quite get it.

Can someone explain in simple terms what this is, why a higher number is better and show a metrics scale of what a bad EF is compared to a good EF? Thanks.
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Re: Can someone explain EF "efficiency factor" in TP in English? [fishgo] [ In reply to ]
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So for cycling EF is basically power divided by heart rate; or in an oversimplified way, how many watts you get per heart beat.

The more watts you get per heart beat the better. You can track this over time as a proxy of your aerobic fitness.

If month after month, your EF factor increases, that suggests your fitness is also improving. Like an FTP test you'd need to do this test under repeatable conditions to be worthwhile.

You can also compare EF within a workout. If you've ever ridden in erg mode for an extended period of time, you'll probably have noticed that your heart rate steadily increases. There are a variety of reasons why your heart rate may increase (e.g. body temp rises, ambient temp rises, dehydration, lose mental focus and technique becomes sloppy, etc). Let's say you do a 3 hour erg workout on constant power, you can figure out EF for the first and second half. If your EF drops a lot in the second half you know there is a potential area of your game to work on.

Like FTP, you can use these measures to understand when your training plan is failing to provide performance improvements, although knowing what amendments to take requires some judgement.
Last edited by: dado0583: Feb 1, 16 9:42
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Re: Can someone explain EF "efficiency factor" in TP in English? [dado0583] [ In reply to ]
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Also just to note that your cadence selection can impact the EF calculation. Let's say you ride for an hour at 100rpm @ 180w, you might perceive it to be very easy. If you ride at 60rpm @ 180w you might perceive it to be harder even though your heart rate is likely to be lower. The latter is going to give you a better EF number, even though it might not match perceived effort.

And as another note, comparing EF between multiple people isn't going to be particularly useful. Let's say you are 20 yrs old and maintain your FTP at the same level until you 50 yrs old. Over (a long) time your heart rate is going to go lower for the same intensity and your EF will increase, but you're not really seeing any performance benefit from it. So it's best not to compare EF across people if possible. Even 2 people at the same age and same FTP may have different heart rates and their EF will be different, but you can't jump to the conclusion that the one with the higher EF is the 'better' athlete, as he may just have a naturally higher max HR rate and zones. Like all these tools they are useful and worth tracking, but not individually without any context.
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Re: Can someone explain EF "efficiency factor" in TP in English? [dado0583] [ In reply to ]
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dado0583 wrote:
Also just to note that your cadence selection can impact the EF calculation.

Also the absolute power output (since there is a negative intercept to the power-heart rate relationship, the ratio of power to heart rate automatically increases with increasing exercise intensity...something that I first pointed out at the 1st power-based training meeting in Philly >15 y ago).
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Re: Can someone explain EF "efficiency factor" in TP in English? [dado0583] [ In reply to ]
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Somehow EF is easier to understand on the cycling side of measurement. But what about on the running side, where I've noticed this (had a friend point it out to me)? EF must then simply be the pace of the run against the HR over a determined length of time (and elevation)? A higher EF would simply mean I'm either running faster at a given average HR or I'm running the same pace at a lower HR. The graph measurement isn't transferrable to other individuals, but higher = better, lower = worse.
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Re: Can someone explain EF "efficiency factor" in TP in English? [fishgo] [ In reply to ]
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fishgo wrote:
A higher EF would simply mean I'm either running faster at a given average HR or I'm running the same pace at a lower HR.

Exactly, both of those things are good when comparing against yourself over time. The same is true of cycling. It's not until you look at this number in the context of a given scenario that it becomes useful.

Example 1:

You're a 10k runner. Your EF goes up. You run at the same HR as previous races and the model predicts you'll be faster in the next race.

Example 2:

You're training for a marathon and have blown up in previous races. Your EF goes up. You run at the same pace (or more precisely NGP) and the model suggests you'll be running at a lower heart rate and less likely to blow up (altho you may still blow up, just later than previously!).

In both examples you'll see 'progress' but I don't know of any models you can plug EF into to predict performance. watts/kg and watts/cda can be used to model your speed on a bike in certain conditions. However I don't believe EF can be used in a similar manner.

One potential usage, which a friend of mine uses for cycling. Let's say you take a winter break, or get an injury and you're out for a while. You know you've lost fitness but not how much. You come back and want to take it easyish and get in some 'base' training before you do max intervals again. You can monitor EF for some workouts and compare that to before the break/injury. Once it's within a certain range, that might be the trigger for when you start throwing hard intervals and FTP tests back into the equation.
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Re: Can someone explain EF "efficiency factor" in TP in English? [dado0583] [ In reply to ]
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Hi,
So how do I see EF tracked over time in TP?
x
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Re: Can someone explain EF "efficiency factor" in TP in English? [Boomwhacker1] [ In reply to ]
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Boomwhacker1 wrote:
Hi,
So how do I see EF tracked over time in TP?
x

Don't think you can. WKO4 has a chart but it shows all rides regardless of length and intensity so it's hard to make heads or tails out of it.

Geoff from Indy
http://www.tlcendurance.com
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Re: Can someone explain EF "efficiency factor" in TP in English? [Boomwhacker1] [ In reply to ]
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I keep it simple: put EF X.XX in the description of your endurance ( Z1/2 )training and use search on EF to get a list.
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Re: Can someone explain EF "efficiency factor" in TP in English? [fishgo] [ In reply to ]
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Yes.

Running EF has units of yards (or meters) per beat. I really think this makes more physical sense than watts per beat. How far to you travel every time your heart goes bump-thump?

As Dr Coggan points out there is some non-linearity in EF (both bike and run). Harder efforts will naturally exhibit a higher EF. So, it is most useful for comparing within a training zone. I don't find this effect to be very pronounced until you get into high z3+ territory. From high z1 to low z3, I find it useful for keeping me honest.

I use it mainly to compare similar efforts over time to "normalize out" minor variations in intensity. It's easy to just go run a little faster today... And be fooled into thinking you got more FIT. Obviously, that's a self limiting thing. You can't just run faster every day.

For me personally, I find the EF metric allows me to stay focused on "the plan" rather than chase a faster pace. Drifting to the top of z2 just to say I went faster doesn't change my EF. But, if I can run faster at the same or lower heart rate... that's where it's at. So, can I eek out 5s/mile at the same 151 bpm?

Another note that since bpm is so heavily influenced by heat index, you still have to compare to similar conditions. You will have a much different EF for lunch runs in the summer, than a morning run in winter.
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Re: Can someone explain EF "efficiency factor" in TP in English? [dado0583] [ In reply to ]
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There is a related metric that shows you your EF drift within a workout or interval:

Pa:hr or pw:hr

Pa= pace , Pw=power

These show the change in EF in the first half of an interval to the EF in the second half in percentage. The general rule of thumb is that a constant effort should have a pa:hr of 5% or less. More than that is indicative of something to work on. Exactly what depends on what isn't holding constant (hr or power/pace).

HR rising at constant effort might mean hydration issues.

HR falling at constant effort (or slowly decreasing effort) might mean a lack of specific endurance... Or improper pacing.
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Re: Can someone explain EF "efficiency factor" in TP in English? [FrankTT] [ In reply to ]
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Genius!
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Re: Can someone explain EF "efficiency factor" in TP in English? [Boomwhacker1] [ In reply to ]
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Non-runner question.......could you use this EF as a proxy for your running economy in terms of your stride, posture, etc.....

It looks like your EF could go up while working on technique while not making any heart related aerobic improvements.
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Re: Can someone explain EF "efficiency factor" in TP in English? [burnthesheep] [ In reply to ]
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Yes, it's the ratio between speed and hr. So if you're becoming more efficient due to better mechanics then ef will rise.
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