Calorie: Garmin vs Strava

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zill
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Calorie: Garmin vs Strava

Postby zill » Mon Feb 09, 2015 8:36 pm

Strava always gives a higher calorie number than the Garmin despite inputting all my personal information. Why is that and which one is more accurate?

Rex
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Re: Calorie: Garmin vs Strava

Postby Rex » Wed Feb 11, 2015 6:53 pm

Hunt through Strava Knowledge Base/Support and they give their explanation, which escapes me now.
Essentially, different algorithms between the two.

Unless you have a PWM & HRM the numbers really aren't accurate at all, but given that I always go with the Strava numbers which for me is always less.

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Alex Simmons/RST
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Re: Calorie: Garmin vs Strava

Postby Alex Simmons/RST » Wed Feb 11, 2015 7:32 pm

Rex wrote:Hunt through Strava Knowledge Base/Support and they give their explanation, which escapes me now.
Essentially, different algorithms between the two.

Unless you have a PWM & HRM the numbers really aren't accurate at all, but given that I always go with the Strava numbers which for me is always less.
An accurate power meter will get you the closest to knowing actual energy metabolised, with accuracy then being a matter of knowing your personal typical gross efficiency (which requires lab testing to establish).

HRMs and other means of estimating energy metabolised are usually not much more than light comic relief.

Put it this way, for such methods to be consistently right, it would mean they are as good as a power meter at measuring your power output.

CKinnard
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Re: Calorie: Garmin vs Strava

Postby CKinnard » Wed Feb 11, 2015 7:57 pm

Depends which garmin you are using. From the 800 onwards, garmin estimates got more accurate.

If you are not Calorie counting what you put in your mouth, there's no point estimating your energy expenditure.

zill
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Re: Calorie: Garmin vs Strava

Postby zill » Wed Feb 11, 2015 10:48 pm

CKinnard wrote:Depends which garmin you are using. From the 800 onwards, garmin estimates got more accurate.

If you are not Calorie counting what you put in your mouth, there's no point estimating your energy expenditure.

How is the 510?

Currently strictly calorie counting what is going in the mouth as well!

Think its going well since if I over indulge one day, the next day will start with the extra calories that accumulated the day before. It's like currency for food.
Last edited by zill on Thu Feb 12, 2015 6:49 am, edited 1 time in total.

zill
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Re: Calorie: Garmin vs Strava

Postby zill » Wed Feb 11, 2015 10:50 pm

Alex Simmons/RST wrote: An accurate power meter will get you the closest to knowing actual energy metabolised, with accuracy then being a matter of knowing your personal typical gross efficiency (which requires lab testing to establish).

You know a good place to get this tested in Melbourne?

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Re: Calorie: Garmin vs Strava

Postby Alex Simmons/RST » Thu Feb 12, 2015 1:29 pm

zill wrote:
Alex Simmons/RST wrote: An accurate power meter will get you the closest to knowing actual energy metabolised, with accuracy then being a matter of knowing your personal typical gross efficiency (which requires lab testing to establish).

You know a good place to get this tested in Melbourne?
I can't vouch for the quality of the testing (such tests are quite sensitive to protocols and quality of equipment calibration) but presumably the VIS would provide a start.

Not sure why you'd bother though.

Illuminate
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Re: Calorie: Garmin vs Strava

Postby Illuminate » Tue Mar 31, 2015 6:11 pm

I found when doing the audax alpine classic this year that the metres climbed value given on Strava far exceeded what was expected based on the course profiles/ others' rides on strava.

I use a mobile phone (sony xperia z3) to record my rides.

I suspect that the GPS is less accurate (not as pin point) as the Garmin GPS. Given that much of the terrain was very steep, the end result of the lack of precision a profile that zig zags upwards/downwards considerably (with a gradual climb up to Falls Creek, even through the gradient was actually quite smooth upwards with relatively few small downs/ups.

Given that Strava uses the recorded profile to calculate total calories consumed, I wouldn't be surprised if this throws the total calories consumed value WAY out.

Just my 2c worth.

Cheers,

BenGr
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Re: Calorie: Garmin vs Strava

Postby BenGr » Tue Mar 31, 2015 10:02 pm

Mobiles will often only use GPS altitude, which is less accurate than horizontal positions (http://gpsinformation.net/main/altitude.htm" onclick="window.open(this.href);return false;). I believe things like strava often try to correct this using map data, but it isn't perfect. Cycle computers often use a barometric altimeter.

https://www.strava.com/activities/155327242" onclick="window.open(this.href);return false; That was using a phone. It has overestimated the climb by about 50%, and the gradient fluctuates far too much. Other rides I did overestimated the climbing by a similar amount.

Interestingly enough on recent rides with a mate his gain using a phone has been comparable to my barometric cycle computer, so Strava might be using a phones barometric sensor now.

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Calorie: Garmin vs Strava

Postby kb » Tue Mar 31, 2015 10:19 pm

Illuminate wrote: I use a mobile phone (sony xperia z3) to record my rides.

I suspect that the GPS is less accurate (not as pin point) as the Garmin GPS. Given that much of the terrain was very steep, the end result of the lack of precision a profile that zig zags upwards/downwards considerably
That'll be Strava's height data + smoothing method. If your device isn't recognised as a device with a barometer, they calculate the elevation themselves. I guess GPS accuracy comes into it to the extent that they probably don't snap to road, so you'll get interesting artefacts near drop-offs :-)
Illuminate wrote: Given that Strava uses the recorded profile to calculate total calories consumed, I wouldn't be surprised if this throws the total calories consumed value WAY out.
Huh, cool. I hadn't realised they used their power estimates for that.

[edit: beaten to the punch :-)]
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CKinnard
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Re: Calorie: Garmin vs Strava

Postby CKinnard » Thu Apr 02, 2015 4:59 pm

The 510 came after the 800 so it is more accurate.


zill wrote:
CKinnard wrote:Depends which garmin you are using. From the 800 onwards, garmin estimates got more accurate.

If you are not Calorie counting what you put in your mouth, there's no point estimating your energy expenditure.

How is the 510?

Currently strictly calorie counting what is going in the mouth as well!

Think its going well since if I over indulge one day, the next day will start with the extra calories that accumulated the day before. It's like currency for food.

durianrider
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Re: Calorie: Garmin vs Strava

Postby durianrider » Sat Apr 18, 2015 12:14 pm

Get a power meter if you want to get close to knowing what cals you are really chewing thru.

HR varies too much and the other methods garmin and strava use are vague at best.

A PM is the best part one can buy for their bike, assuming they already have a saddle.

I have them on all my most used bikes. I can afford any product on the market but found the Stages the lightest, stiffest and easiest to slap on my friends bikes in a few minutes.

*I don't sell or work for any power meter company. Nor am I sponsored. 100% unbiased.
Vegan since 2001.

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zill
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Re: Calorie: Garmin vs Strava

Postby zill » Sat Apr 18, 2015 2:06 pm

durianrider wrote:Get a power meter if you want to get close to knowing what cals you are really chewing thru.

HR varies too much and the other methods garmin and strava use are vague at best.

A PM is the best part one can buy for their bike, assuming they already have a saddle.

I have them on all my most used bikes. I can afford any product on the market but found the Stages the lightest, stiffest and easiest to slap on my friends bikes in a few minutes.

*I don't sell or work for any power meter company. Nor am I sponsored. 100% unbiased.

Got Stages, the thing is for people who are right handed, their right leg is dominant as well so do you think Stages tend to underestimate power for right side dominated people or is the inherent level of variation in the Stages PM large enough to render this issue insignificant?

Also when out walking or running, what is the best way to measure calories burned? I have been recording walks on the Garmin then upload on Strava and specify that it's a walk. Stava then calculates calories burned. Is that way accurate? Are there more accurate ways of measuring calories burned when walking and running?

zill
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Re: Calorie: Garmin vs Strava

Postby zill » Sat Apr 18, 2015 9:34 pm

Have finally "verified" for both walking and running that Strava includes all calories burned such as the basal metabolic rate.

When riding, Gramin does not count the basal metabolic energy spent. It also assumes that the body burns a little over 4 times the amount of energy spent on pushing the cranks. In other words the body is a little under 25% efficient at transferring energy to the cranks.

Note that I use a Stages power meter.

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