Power Geek Question - EF and Pr: HR

Dino Sarti

I am reading Friel's newish book, "Power Meter Handbook".  I am vacation and running low on cycling mags.  It is interesting, sort of, but really just kind of a watered down version of Allen and Coggan's work, albeit way more digestable.

Anyhoo, he spends quite a bit of time talking about Efficiency Factor (EF) and decoupling (Pw:Hr), both of which are there, front and center on Training Peaks, but I never bothered to learn what they ment.

Friel suggests that both are a good indicators of aerobic endurance and he recommends a few  rides that will give you the indications these numbers reveal.  The rides are basically steady efforts  below threshold at an aerobic pace with little to no VI (sub 1.05) to get a good read on EF and Pw:HR.  EF is straight forward - simple ratio of power over HR.  The higher the ration, the better fitness.  A high VI ride will not give you the right data.  

Pw:HR is a little more complex, but similar in that it looks at the relationship of Power and Heart Rate, but does so splitting the ride.  It looks at EF for the first half and then EF for the second half.  It takes the diffence in the two and then divides that difference by the first half EF.  Bascially it tells you how much your HR drifted during the ride.  Meaning, as fatigue set in the backhalf, how did that compare EF to the first half.  Friel suggest a number of 5% or less is "good".

My question is - Is anyone paying attention to these numbers?  If so why, and what have you learned?

Al Truscott

Dino - No, and No (I don't pay attentiion, and thus have learned nothing). But you piqued my interest, so I read the relavent TP article by Friel, and calculated the numbers on several different rides:

• First, my last race rehearsal, when I felt as fit as ever in my life. My Power/HR for 1st/2nd half of the ride were: 1.28/1.233 with an Efficiency of 3.67%. So according to Friel, I was as fit as I felt. remember, this is a ride @ 0.67IF for nearly 6 hours, so any decoupling effects should have become apparent.
• For giggles, I then looked at the previous RR (actually, an Ironman leg) 4 weeks earlier, when I felt "less fit". My HR avg for each half was 116, 10 bpm higher than the RR above; my power for the first half was the same, for the second half, down by 10%. Efficiency was 8% excluding the final 12 miles, which are downhill, 9.4 % including the final downhill. So my feeling of fitness being not so good was borne out by the numbers. But I already knew that from my HR numbers alone.
• Today's FTP intervals 2 x 15' (4'). Looking at the intervals, my Power/HR for each were 202/129 and 202/127. Within the second interval (when any decoupling should have started to become apparent), the 1st/2nd halves were 1.6/1.54 for Efficiency of 3.75%.

I don't know what Friel would say about today's #s, as they were @ FTP, not the 65-75% of FTP he recommends. I guess it's possible there may be a use for this concept, e.g., if one's Efficiency stabilizes over a week or two in these intervals, then maybe it's time to re-test? OTOH, I'm in the phase of the OS (week 5) where the total work time of the FTP intervals is still rising. I think a better test would be to see what happens when I get to 40 minutes of work time, stable over 2-4 sessions, and see i I'm still under 5%. By then, according to the plan, it will be time to re-test anyway.

Interesting.

 

Dino Sarti

Thanks for the replay, Al. Based on the sound of the silence, I am guessing that you me and and Friel are the only ones that find this interesting.

Coach Rich

Friel came out with this decoupling thing a few years ago...maybe '09 or so. We had a good thread on it but it may be in the old, EN 3.0 forums, not sure. 

The short answer, in my opinion, is that your HR can high / low on any day for any number of reasons and that there was little usefulness to tracking this number. IMO, changes in fitness are best reflected in our ability to hold higher power numbers across a range of ride times. Tracking _that_ is more useful. 

Peter Wick

Okay, I'll re-open this thread. I've been searching for some HR & Wattage discussions here because I'm perplexed by something I saw in today's bike test.

In the VO2max 5' test I had an average of 337 watts and a HR of 177. I went out way too hard and really suffered to hold whatever level I could. Then I did the 20' test after a 10 minute rest and averaged 259 watts. My HR was at 170 within the first 2 minutes and just steadily inched up to 176-178 by the end of the test.

Shouldn't the VO2max HR be higher? Or, am I working harder than a true FTP level effort? Is it just what it is for me?

Al Truscott

 Peter...maybe five minutes @120% of FTP is not long enough to reach maximum steady state HR?

Peter Wick

My max HR on the bike is in the high 180's but I only get there on hill climbs. I also did this 5' test poorly so maybe the HR would have gone higher if I had not gone out so hard in the first minute and saved the surge for the final minute. On some of the local hills the effort is a couple of minutes or so and the tops go up over 15%. When I'm trying to make a Strava statement I do manage to get a bigger number but I know that is solidly in the anaerobic zone.

Coach Rich

I don't think it's very useful to track HR or try to analyze it too much on these FTP and VDot tests, especially considering that you're likely testing and training indoors vs the outdoor training you'll do later in the year. 

Looking at HR will be more valuable in your long rides later in the season, as you observe changes and trends with regards to watts, fatigue, temperature, cadence, and any number of other variables. These training trends and observations will be what you'll use to make decisions on race day.

For now, in the OS, just push the watts and observe HR, but don't try to interpret too much from it.

William Jenks

I think Friel would probalby say that his decoupling measure is more useful for low intensity work and also that he means it to be useful for people doing his "normal" periodization. His original logic was that you had to be able to do the aerobic work for X amount of time with low decoupling before eaning the right to do "fast" work. That philosophy is pretty much backwards to ours, which is one reason I pretty much ignore it. I'm sensitive enough to figure out when I feel like crap at the end of a ride. :-)

new2703

Wouldn't EF be a good indicator of possible IM success? Especially for someone like me, who is new to training. One thing I learned this fall in marathon training is my Z1 pace and HR were way off. To run @ 8:40 min/mile my "easy/recovery " pace my heart rate was up around 140-145. This is well above my 65% heart rate. This tells me I'm not very efficient and after a while I will probably drop off in pace, bonk or cramp. This also tells me that maybe I need to focus more on long slow distances.

Al Truscott

@ John - For What It's Worth, the HR I see on my best IM marathons, when I'm hitting about 10s/mi slower than my EP and keeping even splits, is in the range of 75-77% of my max, not 65%. I really doubt anyone who is performing well, and is well trained, is running at an HR down that low during an IM marathon. Anyone with that experience, meaning you've run an IM marathon @ close to your EP, kept a steady pace, yet kept your HR well below 75% of max?

new2703

@Al, that's good to know. I'm curious what others HRs have been during IM marathons and how that correlated to pace

Pina

 @John, Running the 26.2 during IM at my EP to 15s slower min/mile pace my HR is 76-80%. Not for the faint of heart, but doable with optimal training and mentally going after it in execution.

rmiller

@John - when you say your 140-145 is well above 65%, what are you basing your 65% off of? Reason I ask is that the traditional formula (220-age) for determining HR zones would put my 65% at 120, and my typical LRP HR of 140-145 (same as yours) is closer to 78% of the max provided by that formula. In short - I see the same behavior in my HR with LRP's that you do.

On the other hand, using the Karvonen formula, which takes into account resting HR, puts my 65% HR at 137 - something much closer to what I'd expect based on exertion level (assuming all other factors that influence HR are kept reasonably equal).

Back to the OP - I think what William mentioned is true - the whole decoupling thing is based on steady state effort throughout an entire workout. The EN workouts, outside of perhaps race rehearsal rides, simply don't work that way. For more detail, check out episode 61 of the tri-talk podcast (http://tri-talk.com/podcasts.asp), where the whole concept is described. The best part about that podcast series is that there are a few times when the caster specifically mentions our own William Jenks a few times as someone who wrote in to keep the podcaster honest with his scientific analysis