power meter vs. heartrate monitor



Randyforriding

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Nov 30, 2012
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Power meters have gotten pretty popular, but they cost a ton and I'm sceptical about their value. I still feel that a simple and inexpensive heart rate monitor is a better indicator of how hard your body is working and therefore more valuable in making choices regarding equipment, technique, training etc. I think the power meter can actually be misleading. I think it is posible for the power meter to show you are producing more power at the same time your heart rate is increased. I think it is the heartrate you need to worry about.
Suppose you have your bike mounted on an exercise stand. Keeping the resistance constant, gearing, and speed constant, a change you make that results in a lower heart rate is good and any change you make that increases heartrate is bad. Or keeping speed constant, but changing gearing, you can determine what an efficient cadence is for you, based on your heart rate. If going up a gear increased your heartrate, that is a bad change.
Crank lenght is probably a good example of how the power meter could be misleading. I think a change in crank length could show an increase in both power and heartrate. The power meter would be saying the change is good, but the heart rate monitor is saying the change is bad. It is the heart rate monitor you should be listening to. It is showing how hard you are having to work.


Randy
 
Originally Posted by Randyforriding .

Power meters have gotten pretty popular, ... I'm sceptical about their value. ...
Clearly.

Use whatever works for you and leads you to the results you're after, many of us who've trained and raced with both measurement devices over the years are less skeptical and have used power meters to gain insight and objective training and racing data that neither HR nor RPE alone can give us.

The arguments have been made here and elsewhere countless times and aren't really worth repeating. Search the archives or search the web for this discussion played out many, many times over the past decade or so. But in the end it's your cycling, your training, and your results so follow whichever path you like and see where it takes you.

Good luck,
-Dave
 
Originally Posted by Randyforriding .

Power meters have gotten pretty popular, but they cost a ton and I'm sceptical about their value. I still feel that a simple and inexpensive heart rate monitor is a better indicator of how hard your body is working and therefore more valuable in making choices regarding equipment, technique, training etc. I think the power meter can actually be misleading. I think it is posible for the power meter to show you are producing more power at the same time your heart rate is increased. I think it is the heartrate you need to worry about.
Suppose you have your bike mounted on an exercise stand. Keeping the resistance constant, gearing, and speed constant, a change you make that results in a lower heart rate is good and any change you make that increases heartrate is bad. Or keeping speed constant, but changing gearing, you can determine what an efficient cadence is for you, based on your heart rate. If going up a gear increased your heartrate, that is a bad change.
Crank lenght is probably a good example of how the power meter could be misleading. I think a change in crank length could show an increase in both power and heartrate. The power meter would be saying the change is good, but the heart rate monitor is saying the change is bad. It is the heart rate monitor you should be listening to. It is showing how hard you are having to work.


Randy
I wish I'd known this before I spent heaps of $ on 2 powermeters! Any truth to the rumour about a new book hitting the shelves called "Training and Racing with a Heart rate monitor"/img/vbsmilies/smilies/ROTF.gif
 
Originally Posted by Randyforriding .

Power meters have gotten pretty popular, but they cost a ton and I'm sceptical about their value.
Entertaining post /img/vbsmilies/smilies/smile.gif

So were my cycling buddies that are mostly 30 years veterans of cycling and some of them former competitors that were once dropping me with ease. The have seen and experienced the results of me training with the aide of a PM as a guide. Even though I am still the only one in my group with a PM, they are a bit less skeptical since I caught up to their level in a pretty short time span.

Now I am answering a lot more questions about training during the warm up miles rather than them mentoring me.
 
The comparison is bogus, since they measure different things. It's like saying we don't need speedometers in cars if we've got a temperature gauge on the engine. An HRM may give us an indication of how hard we're working, but it says nothing about the load and output we're producing. Sure, if we only rode on flat tracks under indoor conditions, like speedskaters or swimmers, lap times would be a pretty good proxy for load and output, but that's not the case at all when cycling on the roads.

Knowing power output on the bike is much better for training than just knowing speed. I'll bet not many of us train without measuring speed and distance traveled and ride time as a crude indicator of what we've done. If we have GPS we can measure elevation gain too, which tells a lot about the work required on the ride. A PM is just a more accurate way of knowing what we've done.

I don't have a PM on my bike, but do enjoy using one on the Cybex trainers at the Y. With the ability to set the load level (resistance) precisely, and look at my cadence, power output (and HR) continuously, I can get a consistent load and workout. They have a couple of the Lemond Spinning bikes in the gym as well. These set the load using a knob which tensions a strap against the flywheel but without the ability to set and monitor a consistent load. I don't use them, or take the Spinning classes, as I'm not motivated to workout without knowing what I'm doing in terms of load. I do weight training there as well, and always want to know what load I'm setting on the machine or picking up. What if none of the weights were marked, and random sizes?
 
Originally Posted by Randyforriding .

Power meters have gotten pretty popular, but they cost a ton and I'm sceptical about their value.
Your post would be far more compelling if you had actually trained with both a power meter and a heart rate monitor for a significant period of time. But, it sounds to me as though you have never owned a PM. So, my basic question is, "What leads you to believe you are qualified to comment on this subject?"
 
Originally Posted by Randyforriding .
Many people misuse power meters and/or heart rate monitors. Either one alone is better than neither. Both together are better than either.

If I use my power meter and a watch, I pretty much know what my heart rate is doning.

If I use my heart rate and a watch, I pretty much know what my power output is doing.

There are situations where power data is worthless. There are situations where heart rate data is worthless.

I know how much my power output changes as the temperature changes. I know how long I can hold my power output at a given level. I know what power output is too high for me to eat or drink effectively. I can same about my heart rate.

I can look at my power output and determine if I am getting sick or being lazy. I can look at my heart rate and tell the same.
 
Originally Posted by Randyforriding .

I think a change in <snip insert whatever that change might be> could show an increase in both power and heartrate. The power meter would be saying the change is good, but the heart rate monitor is saying the change is bad.
You are going to have a hard time explaining how being able to produce more power is a bad thing.



Quote: Originally Posted by Randyforriding .

It is the heart rate monitor you should be listening to. It is showing how hard you are having to work.


Well since a HRM only measures the rate your heart beats, then no, it doesn't. The only thing that can measure work is something that measures the rate at which energy used or transferred, and time.

Granted a HRM can be used as an indicator of intensity, but it does have some limitations in that role, e.g. cardiac drift, cardiac response lag, only helpful in sub (aerobic) maximal work and not much help when effort becomes more variable.

A power meter can also be used as an indicator of intensity and does not suffer the same limitations as a HRM.

But the main difference is that's about the limit of the use of a HRM. Fortunately a power meter can be used for many more things to aid in improving performance than just as a guide to exercise intensity.
 
Originally Posted by Alex Simmons .

But the main difference is that's about the limit of the use of a HRM. Fortunately a power meter can be used for many more things
Yeah. You can use an expensive power meter as a cheap altimeter.
 
Isn't a power meter that thing inside the metal box attached to the outside of my house...?
 
Sorry Randy been there done that, did well I might add, but HR is soooooooo much more misleading than power!!! P.S. if your wife is giving you a hard time about buying a power meter put the effort in convincing her that you need one vs convincing yourself that you don't ;)
 
Originally Posted by Conan .

Isn't a power meter that thing inside the metal box attached to the outside of my house...?
Yes, and they measure the same thing - rate of energy use and total energy consumption. Household power meters often however only display cumulative energy use up to a given point in time, and don't give second by second data in order to better examine how and when you used the power (which is what our bicycle power meters do). Perhaps more modern house meters may provide this feature but not where I live.
 
Originally Posted by Alex Simmons .


Yes, and they measure the same thing - rate of energy use and total energy consumption. Household power meters often however only display cumulative energy use up to a given point in time, and don't give second by second data in order to better examine how and when you used the power (which is what our bicycle power meters do). Perhaps more modern house meters may provide this feature but not where I live.
C'mon Alex, I was mocking the OP... it wasn't a serious question! Besides, a meter box strapped to your bike would be pretty un-aero!/img/vbsmilies/smilies/smile.gif
 
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