Garmin Edge 305

[KlapperKnop]

I have a technical question regarding an Edge 305.

 

How does Garmin calculate the energy consumption?

I took my Edge 305 yesterday in the car, travelling from PTA to JHB ... According to the data, I have consumed 1545 calories?? How could that be possible? or is the calculation based on an assumed energy expenditure?

[IanJ]

Is is calculated, based on your weight, distance travelled, speed and ascent. Obviously not very accurate but at least it is a guide line.

 

In your case it was assuming you were riding your bike not cheating and using the car .

 

 

[KlapperKnop]

thanks Ian, I would have thought it would also use your heart rate as an input to the calculation, which in my case should have been 0 ...

[NotSoBigBen]

Yip must agree with IanJ, interesting though that if you use it on a both a road and MTB surely it gives different values for a similar time and effort spent due to the much less distance on an MTB?

[IanJ]

True I think it does, you have a point.

 

Maybe in the absence of HR it just uses the other factors because theoretically it can still calculate it based on speed and gradient etc.

[scotty]

Switched mine on when travelling back from CT on the train, the unit was displaying more calories consumed than i was drinking beer (calories)

 

That's one way to do it

[NotSoBigBen]

I know for sure that when I import my data into SportTracks from my Forerunner 301 that it always gives calories spent with or without my HR belt on. Guess it's clevererer than we thought ............

As IanJ says it assumes you're on your bike and not your cage on the highway!

[KlapperKnop]

I think that Polar uses HR as an input to calculate energy expenditure .... anyway suppose Garmin is not going to change the way they calculate energy expenditure ....

[KlapperKnop]

In fact now that I am thinking of it, the calculation is will always be incorrect if they use speed plus gradient as primary factors to calculate ...

 

For example, 2 riders, both same weight doing the same course ... surely they will have different energy consumption, due to their fitness and physique ...

[IanJ]

No the energy expenditure remains the same. To move the same mass the same distance at the same speed would require the same amount of work.

 

The fitter guy would just feel better at the end of it.

 

[niterider]

 

No the energy expenditure remains the same. To move the same mass the same distance at the same speed would require the same amount of work.

 

The fitter guy would just feel better at the end of it.

 

 

The only possible difference would arise from the slightly different efficiencies we have in performing the work. Some people's engines are more efficient and they can do more work for the same energy consumption, or the same work for less energy used.

 

[NotSoBigBen]

No the energy expenditure remains the same. To move the same mass the same distance at the same speed would require the same amount of work.

 

The fitter guy would just feel better at the end of it.

 

The only possible difference would arise from the slightly different efficiencies we have in performing the work. Some people's engines are more efficient and they can do more work for the same energy consumption' date=' or the same work for less energy used.
[/quote']

 

I could be wrong but I doubt my Garmin would notice that, yours IanJ?

[niterider]

 

No the energy expenditure remains the same. To move the same mass the same distance at the same speed would require the same amount of work.

 

The fitter guy would just feel better at the end of it.

 

 

The only possible difference would arise from the slightly different efficiencies we have in performing the work. Some people's engines are more efficient and they can do more work for the same energy consumption' date=' or the same work for less energy used.

[/quote']

 

I could be wrong but I doubt my Garmin would notice that, yours IanJ?

 

Definitely wouldn't. You'd only figure out the efficiencies in the lab.

 

[IanJ]

[

I could be wrong but I doubt my Garmin would notice that' date= yours IanJ?

[/quote]

 

Oh no mine does, it knows me intimately it is perfectly in tune with my riding style etc. .

 

You must have bought a cheaper model BB.

 

 

[NotSoBigBen]

'riding style' - Ahhhhhh IanJ therein lies the answer, should one have no riding style how can it get to know you

 

So of to the LBS to see if I can buy it along with some of that 'flow' stuff that LittleBen keeps telling me I'm missing!

 

Yes it iss a mere 301 not the superior in number as well as feature 305 model I'm afraid

[KlapperKnop]

No the energy expenditure remains the same. To move the same mass the same distance at the same speed would require the same amount of work.

 

The fitter guy would just feel better at the end of it.

 

 

Correct, if both cyclist have the identical spec of bikes etc. However, this is never the case ... assuming me and u are the same weight .. but or bikes are different and over the same distance, your average heart rate is also different as you are fitter .... that means my heart had more heart beats than you, I used more oxygen to my leg muscles, which I would want to think that my leg musles consumed more energy for the same distance, because our total weight (body plus bicycle etc.) was different? I have worked harder ....