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Any thoughts for estimating calories burned biking on a trainer?

macgurlnet
macgurlnet Posts: 1,946 Member
edited November 29 in Social Groups
Figured I would ask here to see if anyone has an idea...

I just got an old road bike set up on a trainer. Pretty sure it's an older edition of this one: https://kurtkinetic.com/products/kinetic-road-machine/.

I have a Fitbit Flex, so no built-in HR monitor for me to potentially rely on for calorie burn. I've just been logging it as Spinning in the Fitbit app so far.

Any suggestions for equipment I could pick up to help get a better estimation of calorie burn here? It looks like the company sells a watt meter for ~$75, which isn't too expensive. Would that be worth getting (assuming my trainer is compatible with it)?

I'm a data junkie and I love toys, but figured I would see if anyone else has input here.

Thanks much!

~Lyssa

Replies

  • sarahmichelef
    sarahmichelef Posts: 127 Member
    I'd say bike computer so that you can log it as a regular cycling activity... the fitbit estimates for spinning are wayyyyy off (it gives me less of a burn from 45 minutes spinning than it does from 45 minutes walking, for example).
  • heybales
    heybales Posts: 18,842 Member
    edited February 2016
    Watt meter would be perfect and way accurate - well, if calibrated accurately.

    Watts shown to be supplied to say the tire are about 22-24% efficient for the body, so the watts your body expended are higher.

    So watts per hour delivered to measuring device / 0.22 = watts body expended.

    Watts x 0.8598 = calories.

    Some devices will assume that efficiency and already display watts your body is expending, not what the wheel is pushing.
    So just the last part of the math.

    Sadly a bike computer being used on stationary is also going to be wrong if it's estimating calories - it's assuming wind resistance, and hopefully asking for your weight to include rolling resistance, though unless it includes incline, knows nothing of gravity resistance.

    But all those values are bogus on indoor trainer where you pick the resistance not only by amount of pressure against roller - but also amount of resistance in selector that effects the roller.
    So the distance isn't correct.
    It is for literally how many inches the wheel traveled around, but without those other values, it's not a real outdoor matching distance - which the calorie formulas would be for.
    Unless you find a site specific to indoor trainer numbers.

    This could probably be tweaked to work correctly - tail wind matching average forward speed to cancel that out.
    http://www.bikecalculator.com/
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