Power & Heartrate comparison (personal experince)

[carbon2329]

I am planning on getting an SRM for a THM M3 crankset I have purchased already.

Over the past 7 years I have trained pretty intensivly for various cycing goals/races:
(as much as possible with a full time career)
-I had a personal coach for 3-4 years (An M.D. who is a coach for BMC currently & other pros)
-Trained 12-18 hrs a week of training on the bike during summer
-Trained 10-12 hrs a week of training on the bike and gym in winter
(just giving context, not trying to "boast" in any way)

I have used Heart Rate as my system of measurment for training. It has been pretty accurate in my opinion. I have become very comfortable and good and using it. It seems to work well. I havent' seen dramatic variences due to hydration, temp, etc...
(in short, it has wroked well for me)

My question is:
1-Who has used both (extensivly)?

2-Has (in reality) a change from Heart Rate to Power increased you abilites due to it's differences and "more accuracy/concistancy".

Small disclaimer:
I am planning on getting the SRM, but in the back of my mind I wonder if I will just end up using the Heart Rate (from the PC7) as my "Barometer" and the Power will just be "just something else on the dash board" (and yes that is up to me to use it, or not)

I just wonder if having the power is a real benifit, if I am very used to the Heart Rate and it has worked well?(perhaps this is a case of something "I don't know, that I don't know") However, something new may bring some fun and a fresh look at things.

I know this is not a new topic, but perhaps, in this context, it will add to the subject.

[Tapeworm]

I have used both extensively. I continue to use both. However HR is only ever a guide now if used at all. For non-cycling efforts the HR is handy for quantifying the effort into the easy, medium and hard range. That's it. For training involving power the HR is recorded more for observation of any unusual HR readings (extremely high or low). Otherwise it's power all the way.

The reason about why power is an excellent tool has been written about extensively. The Wattage google group is an excellent resource.

Personally I love the clinical accuracy of power. The easy efforts are now truly easy. Hard is really hard. Energy expenditure is now accurately recorded. And overall training stress is easily recorded.

[carbon2329]

For non-cycling efforts the HR is handy for quantifying the effort into the easy, medium and hard range. That's it. For training involving power the HR is recorded more for observation of any unusual HR readings (extremely high or low).

Personally I love the clinical accuracy of power. The easy efforts are now truly easy. Hard is really hard. Energy expenditure is now accurately recorded. And overall training stress is easily recorded.

Thank you Tape, Can you go into greater detail regarding how "Energy expeduture is now accurately recorded".
That is the exact thing I am looking for.
For example: with Power, are you saying when trying to obtain a specific "effort", the Power is more cosistant so the effort might not be so "up and down" with variences in road (ie.small inclines vs. flats etc...)

The reason about why power is an excellent tool has been written about extensively.

Very true, we don't need another thread like that. I am hoping for a very narrow, description of how others use the Power data, and how it's accuracy separates if from the (apparent), broadness of Heart-Rate.

Does that make sense?

(I have searched, but the results are totally random.)

[2002SaecoReplica]

I've used/raced/trained using both for years. Last year I ditched the HR all together and go off of straight power.

There are a lot of things that can influence your heart rate. Stress level, caffeine, not enough sleep or poor quality of sleep, dehydration, ect, ect. With power you know absolutely what you're doing. For me personally, during the base and transition periods I've benefited greatly from being able to do specific work outs at target wattage. So if I need to go ride a 15 minute transition intervals at 280-290watt average I know that I've getting all of that intensity where as with HR on a downhill section your HR could stay high while you're not actually going as hard as you should be. Or, if you start to get fatigued you'll see some cardiac drift.

The major thing is knowing how to train with a power meter otherwise it just becomes a really expensive cycling computer. I personally thing that a power meter along with some quality coaching will really help you improve. The number of hours trained is semi-irrelevant. What's more important is how many hours at what intensity?. Again, I think quality coaching in tandem with a power meter can help you the most.

[chase196126]

A power meter is recording the exact amount of energy that your body is putting into the pedals of the bike, rather than measuring a physical symptom that is reactionary to the power output. Your HR can vary for a given power for so many different reasons that it is only a rough estimate of what you might be doing.

The advantage of using power is that you can immediately find the zone that you should be training and stick precisely in that zone for the allotted time. With HR you have to wait on the lag for the BPM to go up, which makes it almost worthless for short intervals. Using power will allow you to avoid over working in the first part of an interval, as well as learning how to maintain a constant effort no matter what terrain you are riding (for example, many people are terrible at sustaining a set effort on rolling terrain). The PM will also help ensure that your easy days are really easy, rather than a little bit too hard to really let your body recover.

The power meter records the energy you are expending as KiloJoules (KJ), which roughly translate to calories expended. Depending on how efficient you body is 1 KJ can equal between 1 Kilo Calorie and 1.2 Kilo calories. You can use this to monitor food intake for weight loss, eating on the bike, etc.

[carbon2329]

So if I need to go ride a 15 minute transition intervals at 280-290watt average I know that I've getting all of that intensity where as with HR on a downhill section your HR could stay high while you're not actually going as hard as you should be. Or, if you start to get fatigued you'll see some cardiac drift.

That is interesting. It sounds like using power "filters" some of the less effective training time out, in a way, by it's inherent (and consistant) accuracy, as compared to HT (heart rate).

Perhaps there has been some inacuracies with HR, I have just not recognized, which I have contributed to other things. As with a PM these inefficient training sections could be reduced or elimiated (that sounds dramatic )

Chase,
The KJ vs. KC is a conection I didn't consider. I do not need to loose weight (I'm 125lbs), but for recovery and comparison between similar workouts, that could be valuable.

Would you say you depend, primarily on PM (compared to HR) or would you say you use HT in conjuction with PM? (if that makes sence)

[chase196126]

Would you say you depend, primarily on PM (compared to HT) or would you say you use HT in conjunction with PM? (if that makes sence)

Personally I train with only Power, I haven't used a heart rate monitor in several years. If you are going to wear a HR strap you should still train with the power rather than heart rate, but looking at the data afterwards can show you how well your HR correlates to certain wattages, how fast your HR responds to efforts, how much cardiac drift you get for a given effort, etc. A vastly different HR for a given effort can potentially indicate when you need rest or when you have become significantly fitter, but the same thing can be deduced from field testing and perceived exertion compared to power output.

I know that Golden Cheetah has a Power/HR "Decoupling" metric that can show how fit you are over time (I don't know much about this metric... You would have to read their website to get a better explanation)

In short, train by power and use HR as an interesting side metric.

[Chiva]

I've been training w/ power for several years now. This last year I ditched the HR strap and use only power. The HR was redundant and if anything misleading. At the Tour of the Gila TT last year I tried to avg about 300 watts. My corresponding HR was about 10-15 beats under my supposed TT HR. If I would have gone by HR I would have blown up early, but b/c I used only power, my pacing was great and rode one of the best TT's of my life. HR is a mute metric when you have power. Plus, the HR strap weighs several ounces:)

[Tinea Pedis]

The power meter records the energy you are expending as KiloJoules (KJ), which roughly translate to calories expended. Depending on how efficient you body is 1 KJ can equal between 1 Kilo Calorie and 1.2 Kilo calories. You can use this to monitor food intake for weight loss, eating on the bike, etc.

Very interesting.

So my ride yesterday, of 4358kJ, would equate to (using the ave, 1.1 kCal) 4794kCal burned? Which for us on the metric system, would mean close to 20,000 kJ burned?


Also, OP, fwiw I second everything that everyone else has said about power.



Edit: also popped it in 'training', a little more appropriate.

[Tapeworm]

I think your follow up questions to me have been answered!

In relation to the energy used this is not just about weight loss - it is also to help correct fuel replacement - highly valuable in certain situations - especially when you weight is very low!

It can also be used as another metric to track in terms of training load.

And TP, yes.

It's why when doing "pro" miles folks you need to eat big. Do that sort of training and eat like a bird and bad things will happen.

Additionally, The temperature readings on the PC7 are as just important in my mind as well as HR. Thermal stress is the "next big thing" in terms of sports science, as its management within the body can greatly limit performance. If only it took core temp readings too....

The only other tidbit I would add is that you train with power and not by it. If each ride becomes an effort to beat the numbers on the display from last time or ride within a mere watt of target wattage etc this will lead to failure. To quote Dr Coggan, "...the zones are descriptive, not prescriptive." Most (but definitely not all!) of the benefits are post race/ride analysis.

[Geoff]

The one thing I will add is that power will allow you to do Intervals better.

If there is one thing that we have learned, it is at Periodization is the key to structured performance. One of the building blocks of Periodization is the use of Intervals to stress the body repeatedly in a known way to make it respond with adaptations. There is no other way of regularly and reliably testing the body, using that data to craft a series of repeatable workouts that create the stresses necessary for the desired adaptations to occur, then recording and analyzing those workouts objectively.

With HR, 107% of your then-MAP always looks the same. The difference is that your early-season and peak-season form results in a different load being required. With power, you can really push yourself with higher loads than you think you can do simply by feel or HR, simply by knowing empirically your body can do it.

[carbon2329]

Edit: also popped it in 'training', a little more appropriate.

Tinea,
Thanks for moving it. I realized the same thing, as soon as I posted it.

With HR, 107% of your then-MAP always looks the same. The difference is that your early-season and peak-season form results in a different load being required. With power, you can really push yourself with higher loads than you think you can do simply by feel or HR, simply by knowing empirically your body can do it.

I wondered about that as well:
With improvements in fitness through the year; is a PM more accurate over time? (When HR will change, but less accuratly).

[boots2000]

I have been training with power for about 11 years.
I use both heartrate and power data.
If you throw out the heartrate- you don't always know how hard you are going to produce X power. You may be right on on some days- you might be busting a gut to hold that number on others.
I agree about not letting power or heartrate hold you back in races though- except for tt start. If you can avoid starting too hard it will likely help your pacing.

[Chiva]

The other thing I wouls add is that training w/ power has made my hard days harder and my easy days easier if that makes any sense.

[carbon2329]

That makes perfect sense.

It seems with HT an easy day is not that easy. Hard days are hare (of cousrse), but with HR it seems an easy day is an "up & down day". (if that makes sense)