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Discussion Starter · #1 ·
I'm 48, started mountain-biking about 18 months ago and have lost 35lbs since I started. I raced about half of last season in the Sports class, finishing mid-pack and I intend to race in the Vets this year.
I've decided that the best improvement I can make to my race speed would be to continue to lose weight. I've targeted a further 15lbs which will bring me to 180lbs which is realistically as low as I can go given my build (ex rugby player type!!). I intend to lose this weight before the 1st National race in April.
I've decided that the most sensible way for me to measure my training effort is by using the calories function on my Garmin. I've set myself a weekly target of burning 5000-6000 calories while cycling and I feel that, along with cutting out the crap in my diet, this will achieve the results I'm looking for. Since the New Year I've taken this approach and so far I'm well ahead of target! I ride 3/4 times a week with my local club - mainly 2 hour non-stop XC training spins.
What do people think of this approach?
 

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What do people think of this approach?
i think the calories thing on garmins aren't very reliable. i've done 2hr mtb rides that are almost exclusively downhill...and it shows me burning 1000+ calories. compared to an hour ride on my road bike on the flats where i'll go close to all out and barely be able to stand up when i walk through my door.....and it'll show 1000 calories burned.

with that said...
Since the New Year I've taken this approach and so far I'm well ahead of target!
if it ain't broke. don't fix it.
 

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I started riding (again) 3 years ago and lost 77lbs the first year.

I still find that watching calorie counter on long rides is a motivation factor, reliable or not!

Keep it up.

:thumbsup:
 

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Discussion Starter · #4 ·
nomit said:
i think the calories thing on garmins aren't very reliable. i've done 2hr mtb rides that are almost exclusively downhill...and it shows me burning 1000+ calories. compared to an hour ride on my road bike on the flats where i'll go close to all out and barely be able to stand up when i walk through my door.....and it'll show 1000 calories burned.
I think "calories" on a Garmin are measured as a function of time and heart-rate so I would expect an easy two hour MTB ride to use roughly the same amount of calories as a one hour intense road spin?
 

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RichardL said:
I think "calories" on a Garmin are measured as a function of time and heart-rate so I would expect an easy two hour MTB ride to use roughly the same amount of calories as a one hour intense road spin?
it's not a function of heart rate - it'll calculate calories for you if you leave your HR monitor at home. and even if it did factor in HR, it still wouldn't be that accurate, since everyone's max/resting/lactate threshold heart rates vary by wide margins. probably some time/distance/elevation equation....which obviously doesn't factor in rolling resistance, wind, and overall effort. ....think pedaling a 40lb DH bike vs. a carbon fiber road bike on the same 10 mile road loop. if you go the same speed with both, the garmin will say you burned the same amount of calories. but in reality it'll take a lot more effort (and thus calories) with the DH bike because of the suspension, weight and huge tires.
 

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Discussion Starter · #6 ·
Thanks Nomit - thats dissapointing!!
So are you saying that if I was to ride 10kms on a flat road and 10kms uphill offroad, both at the same speed, then my Garmin would reckon the same calories for both rides?
 

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My impression is that the Garmin is a relatively accurate reflection of effort...it is definitely harder to ride 3.5 mi uphill from the close busstop than 11 mi (down & then flatter) to the far busstop, and the calories show higher on the shorter uphill ride. I think some combo of elevation, speed & time may be used to calculate it. But it will not account for other things that may make it harder, like a headwind or snowy slippery roads, so don't take it too literally.
 

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RichardL said:
Thanks Nomit - thats dissapointing!!
So are you saying that if I was to ride 10kms on a flat road and 10kms uphill offroad, both at the same speed, then my Garmin would reckon the same calories for both rides?
i believe it would say that the uphill ride burned more calories....since the garmin is able to factor elevation into whatever math it uses to calculate calories burned...

i just don't think its that accurate overall - there's simply too many unknowns for it to come up with a reliable number every time. if you use it on the same bike, with the same person, on the same type of terrain...you could probably still use the information to compare ride to ride how taxing a specific ride is on your body. but the calories burned may be 20% higher than reality, or 20% lower....and just looking at your ride profile (speed/elevation gain) and HR data and figuring in your own PE (perceived exertion).....you should be able to make a decent guess anyway.
 

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I can not remember where I got this (Friel or Charmical maybe)
What I use is a unit called work. you take the total time you
ride in each heart rate zone and multiply it by the zone:

10 in zone 1 equals 10
10 in zone 2 equals 20
10 in zone 3 equals 30
10 in zone 4 equals 40
10 in zone 5 equals 50
total work: 150

and add it all up, and that is the total amount of work
Set up your garmin with your max heart rate in the zone setting.
and when you down load to your pc you can see all the zone times
in the totals tab

While I record time, mileage and calories, "work" is the one I use
to judge what I do.

Bigmark
 

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I think the way that you are quantifying your training is totally fine, because it is consistent.

While kilojoules on a powermeter might me more precise, for your purposes, using the Garmin/Trainingpeaks kcal measurement will give you a consistent measure of how much work you are doing, even if it might not be the precise amount of kcal's burned.
 

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^^^^^^^^

This

The units we use to quantify exertion are really arbitrary anyways (Watts, Joules, beats/min, whatever), it's how consistently quantify them that matters. Power is favoured because of how repeatable the measurement is, whereas something like heart rate (or anything derived from it) is going to be more variable due to physiological state that day, the lag that occurs, ability to recover, etc. As long as you aren't using the calories burned to change your caloric intake, it is a perfectly suitable measure to gauge your workouts by.
 

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Discussion Starter · #12 ·
Many thanks for all the helpful advice guys - I appreciate it.
I am not concerned as to whether my Garmin measures accurately how many calories I have burned but whether the number it gives me is a fair reflection of the effort I've expended on a particular ride as compared to other sessions. I'm very surprised that the Garmin can't do this given that it measures heart-rate, distance, speed, elevation and it has my weight, age etc programmed into it!
Anyway it's far more important to use what I have and get on with it so here goes .....
 
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