WhyFi

I think that it's fairly common to have imbalance at different outputs or fatigue levels, as well; for instance, someone with a 50/50 balance at tempo may be 42/58 at sprint outputs, etc, so even a blanket adjustment may not tell the whole story. As always, though, whether or not that's important depends on what you intend to do with that info.

procrit

I think the balance is usually reversed. You might see 45/55 for zone 2 but I think most people get much closer to 50/50 once they go above tempo.

Carbonfiberboy 

That's sorta true. One can watch the rate of HR rise, which is also good information. The HRM will tell you about your more or less average effort, which is still good information. HR will also tell you things that power does not. I trained with just HR for 25 years, didn't get power until late '19. Training with power has made it mentally easier, but I don't think it has had any great effect on my average speed on hilly rides.

tempocyclist

I totally understand. It's why I got one! 😁

tempocyclist

Yep I definitely notice an imbalance difference at different outputs and fatigue levels. Pretty much spot on 50/50 when fresh and below threshold. Head into VO2 territory and it swings to 48/52 balance or "worse" if I'm tired. What do I do with this L/R balance information? Nothing. I'm actually not sure if there is anything I can do about it. 🤷‍♂️

Seattle Forrest

​​​​​​L/R balance and Platform Center Offset are both hugely valuable to me. My form also breaks down with fatigue. I have a 3 year old tendon injury in my feet and ankles. I make it worse when there's too much pressure on the tendons I injured. It's healing up and giving me less pain, but I can sort of come close to reinjuring it. When my L/R B shows that I'm starting to unconsciously favor the less injured foot, and PCO says I'm applying force through the injured tendons (by supinating on the pedals) I take a few days off and wear shoes that give me the most protection off the bike.

Dancing Skeleton

Favero Assioma.
I've got Duo on one bike, Uno on another.
Reasonably priced, easy to use, easy to switch between bikes, great battery life.
I have several pairs of shoes, some with Look Keo grey cleats, some with Favero's own cleats.
All work well.

cyclezen

Actually, in your scenario HR is exactly what you need to make good decisions on how to ride what's ahead, especially where the efforts are extended, like a climb or hard, long tempo.
Yes, there is a slight delay in how your system/heart reacts to efforts, but it's just a sec or 2 delay.
Your HR tells you where you are within your own capabilities. If you're already into the red zone, knowing what your power level is, is academic. Because it's certainly not going to rise or hold for very long. Push further in the red zone and the inevitable 'blow up' will happen. Power numbers mean nothing if they aren't placed into some definition of the standing of your system.
Key to using any of these tools is knowing and defining yourself within the parameters and metrics each system provides. If that hasn't happened, then the numbers are just numbers.
Having both systems and defining/ knowing how you line up within both, is the best of scenarios.
If on your hypothetical 1/2 mile hill, you find yourself well into your anaeroblic zone, then how much power you're producing or think you can produce is, again, academic.
If, however, you're not yet fully Red, then digging deeper for more power, might be possible.
There are constant reminders of this, watching the Pro races. Very often riders get 'dropped' (actually holding their current effort and not reacting to jumps) and find their way back to those who dropped them. Not because their power was inadequate, but because they know themselves enough to not be tempted to go Red and blow up. Marc Soler showed exactly that, very clearly, in his recent win in the Vuelta, and in more than one stage.
HR has much to tell a rider, if properly understood, used and defined - as does Power. If one doesn't put them into a well defined personal framework, they're just numbers.
Ride On
Yuri

waters60

I am fairly sure it has made me slower on 100 mile / 10,000’ rides! By limiting my power output on hills I keep at a pace I know is slower but I also don’t want to blow up. HR is important in its own right, especially after big rides when the next day you have a hard time getting out of Z2

Carbonfiberboy 

Before I had the PM, I did those hills by HR and of course my pace got slower near the top. Strava had good info from me, so with the PM I just used the average Strava power on those same long climbs, worked fine, but same result for time. Now I watch both. HR is really good at seeing when your blood sugar is dropping (HR drops at same power, apparent effort increases) and when you're dehydrated (HR rises at same power). Of course I don't really need the PM to notice those things, but it helps. Yeah, next day HR is totally in the toilet so I just do a short Z1 (power) on the rollers. Even 15' helps. I couldn't go the next day, even when I was a kid.

terrymorse 

The heart rate response delay is much longer than 1-2 seconds. Coggan says it’s on the order of 1 minute.

cyclezen

LOL!, not likely... a one minute delay would have humans constantly passing out. ... or not being able to do any physical exertion, as the other option. You either deliver O2 to both muscles or brain, or one area suffers greatly.
if you watch you're own heart rate change to any sizeable change in activity - 1 to 2 secs at most.
Ride On
Yuri

mschwett 

this is really valuable for me; my main metric of "how i'm doing" is actually the relationship of heart rate to power. 99% of my riding exists in a range between 90 and 130BPM, and if the pretty tight correlation between power and HR (for a steady state over a few minutes) is off i know that something is "wrong," so to speak - or on occasion extra right. on the really wrong days i know to just throttle back and have an easy cruise, and the "extra right" days where an extra 20 watts came from the sky at the same heart rate, breathing is good, the bike is quiet, it's time to go for some PRs.

terrymorse 

I think Andy Coggan knows quite well how the heart responds to exercise:

"However, while theoretically sound the use of HR [heart rate] to quantify training intensity does have certain practical limitations. One is that although HR is closely correlated with exercise intensity in a laboratory-type setting, this relationship is not nearly as strong while cycling outdoors (Fig. 1). This is due to the wide variety of factors that can influence HR during exercise. For example, altitude, heat, hypohydration/dehydration, recent illness or infection, lack of sleep, and large fluctuations in power output (e.g., in a group ride setting, or in hilly terrain) all tend to increase HR during exercise at a given intensity, whereas acute overreaching has the opposite effect. In addition, the relationship of HR to power can differ between individuals, even if normalized in some manner, e.g., to the HR measured during a time trial (TT), or to maximal HR measured at the end of an incremental exercise test. As a result of such factors, the actual demands imposed by training can differ considerably between workouts or between individuals even if HR or relative HR is kept the same. Moreover, since HR responds relatively slowly (half-life = ~30 s) to changes in exercise intensity, HR monitoring cannot be used to regulate the intensity of shorter efforts, such as brief intervals aimed at enhancing anaerobic capacity or sprints designed to increase neuromuscular power."

Andrew R. Coggan, Ph.D., Training and racing using a power meter: an introduction, 25 March 2003 (revised)

RChung

Andy's talking about something related but slightly different: an initial "impulse" in power has a HR response that's quite quick but it has a HR response that lasts a long(ish) time. You can see that if you look at power and HR traces: HR jumps up faster than it falls (i.e., the response is asymmetric).


As a historical oddity, it's kind of amusing whenever I see a reference to that March 2003 version. Not many people had access to pdf-generating software in 2003, so Andy sent me the original Word document and I converted it. Like many Word docs, I had to fiddle with a couple of the graphics to make them fit. I still have Andy's original .doc file.

Carbonfiberboy 

Of course Coggan is correct. However, his use of the word "response" is sloppy. I see a response in seconds. However say one is doing a 3 X 3' X 1.5' Z5 interval set and has a PM and HRM. Going by power, HR will probably take the whole first interval to reach steady state, if it even gets there. Second interval, it'll come up quicker, 3rd interval maybe at 1.5'. Which depends to some extent on conditioning. The better one's condition, the slower it comes up IME. So HR actually responds very quickly, it's just that it takes time to reach steady state at steady power. The experienced HRM user allows for this and can guess at the steady state number by the rate of response.

Say you're going to do 10' hill repeats on a steady grade with just an HRM. You guess at the effort and watch the numbers. When you reach your goal HR, you look at your speed. Next interval you just hit that speed right away and then adjust speed to hold the desired HR. This time you notice how far you got up the hill. On succeeding intervals you start with speed then hold HR steady. When you notice that, going by HR, you haven't gotten as far up the hill as on previous intervals, you maybe do one more, maybe not, but you know you've tired. So there's a different philosophy that's being applied. With power, you just hold power steady and ignore HR.

Thus over the set, if it's long and hard enough, you'll be changing HR zones, which will mean that you're also changing the percentages of what you're burning to create that power. Thus using power or using HR, one may not be getting exactly the same training effect. On long climbs, holding HR or holding power, it can happen that the PM rider will blow up and the HR rider will not. I use both. Doing hill repeats, I hold power steady and quit when my HR changes zones. Maybe I'm a wimp.

cyclezen

He's wrong.
Very simple to try and observe yourself.
With a decent HRM, bring yourself up to a steady effort, steady bpm reading, good to be at 140 ish bpm. Get up and sprint or any other much HARDER effort (climb, whatever).
You will see the bpms rise within 7-10 secs or less.
On my VDO HRM with wahoo kickr strap, I see the displayed rise in bpm starting within 5 sec. there is a delay due to equipment and wireless.
On my recent purchase Garmin Edge 130 and Kickr the display starts noting in 7-8 sec.
try it.
Ride On
Yuri

asgelle

It seems like you're talking past each other. You're talking about the initial change from baseline with an increase in effort. Coggan is talking about the time it takes to reach a new pseudo-steady state at the new intensity. Both can be true.

merlinextraligh

Basically adds up to HR alone has limitations, including the lag in response, and drift from fatigue, dehydration etc.

Use HR, power, and perceived effort, together and you’ve got more insight than HR alone

terrymorse 

Yes, I think this is the case. I’ve noticed my HR starts to rise about 10 seconds after increasing the power, but HR doesn’t level off to a new level until at least 30 seconds later.

In the other direction, the HR response seems even slower. If I reduce my power, it seems to take forever for HR to drop back to the “lower power” value. Not forever, of course. But it’s definitely longer.

terrymorse 

I remember receiving the PDF when Andy was asking for comments.

The amusing meta info from that March 2003 document (Distiller 4, Word 9):

waters60

Yesterday I did a ride I have done for years. 106 miles, 10,000’ climbing. Of course at 62 I don’t go as fast as when I was 30. In fact I strategize how to come back in one piece and enjoy the ride. Whopping 12.9 mph avg HR 123. I used HR for years before I got PM pedals so I make a habit of watching HR. I can tell without looking what my HR is. It varies but I know how it responds. There are some very painful hills on this ride. What PM does so much better than HR is tell me exactly when I want to shift on hills that have a rapidly increasing series of pitches.On short rides this concern about conserving energy is not as important but I don’t want to make the call of shame 50 miles from home!

RChung

There's a story about that, too. March 2003 was a pretty wild time: we'd invaded Iraq. In early June I was producing a pdf of one of my own papers when it occurred to me to check the metadata for the pdf I'd produced from Andy's .doc. It still had my default metadata, so I had to re-generate that pdf, and I gave it those fields. As yet another aside, he used North American month-day-year date format. That "Revised 25 March 2003" on the front page was added by me to let people know the June re-generation was the same content as the previous version, it just had different metadata.

kyle13

I've been looking at watches that I might upgrade to, and have been comparing the Garmin 955 to the 255. One feature of the 955 that's interesting is the Advanced Cycling Dynamics. Are Power2max, Favero, or any other non-Garmin power meters compatible with that?

jackyharuhiko

Favero Assioma pedals are compatible with advanced cycling dynamics except for pedal offset. All others are supported.