UNIDENT

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The Great Stationary Cycling Experiment

Saturday, September 22, 2012

In yet another experiment borne of message board discussions, the question arose as to whether your body weight actually does make much difference in stationary cycling. One poster said that it does, because Spark gives significantly different burn rates for heavier people for the same workout. Others said that the resistance is entirely magnetic and your individual body weight is irrelevant.

So the experiment...

Using myself as an estimation, therefore pretty identical actual HRs during the two bouts, so the only variable is the weight plugged into the device...

10 mins stationary cycling at 18mph, with the weights of 250lbs and 120lbs plugged into the Bike and the HRM.

Spark Stationary = stationary cycling,vigorous, greater-than 15mph

Calories burned at 250lbs:
Bike: 95
HRM: 97
Spark Stationary: 219

Calories burned at 120lbs
Bike: 84
HRM: 81
Spark Stationary: 83

Results:

The bike and the HRM reported similar but only slightly lower burn rates for the lighter person, given the same HR recorded over the durations. Spark, which doesn't ask for HR, indicated an incredibly significantly higher burn for the heavier person, and a burn more matching the other devices for the lighter person.

Notice that Spark's figure of 219 for 10 minutes of exercise for the obese person is 22 cals per minute - which is pretty much physically impossible. Exercise almost never gets above 14 cpm, and most exercise is 6-12cpm depending on intensity and your weight. Given cycling is a very low intensity lower-body-only activity, it's incredibly unlikely that it would realistically be anywhere near 22 cpm even for the most grossly overweight of individuals.

Conclusion:

Spark erroneously takes your weight into consideration when calculating burn on a magnetic resistance device. Neither the device, nor my HRM, report that the burn would be significantly different for a heavier person, but Spark reports a phenominal difference - more than 2.5 times the burn.

Therefore I would STRONGLY caution AGAINST using Spark's estimates for any magnetic resistance workout, and instead use an HRM, or the machine reported figure, or seek an average from other online sources.
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Member Comments About This Blog Post
  • UNIDENT
    UPDATE!!!

    Spark have updated their calories burned calculation for the elliptical and it is much more reasonable and less dependent on your own body weight.

    They say the exercycle update is coming, too...
    2638 days ago
  • KPILVER
    I often find myself entering less minutes than I actually spent on the eliptical machine into the tracker because sparks calorie estimate is higher than what the machine says I actually burned.
    2679 days ago
  • GRACEFULIFE
    Most of the burn calculators are wrong, hence I've been suggesting getting cardio calorie burn from a chest strap style HRM for many years.

    There is a closer calculator out there that takes into account VO2max, which there are several ways to estimate. My HRM does it, and there are time trial methods for many endurance activities.

    Cycling can be higher intensity depending on how you go about it. I agree that magnetic resistance units don't really create high intensity - I think I could pedal my rim-drive trainer on top resistance in top gear on my MTB forever. By the same token, I can easily entirely exhaust myself in 5 minutes or ~3 intervals on my spin bike (with felt pad friction mechanism). When I do so, it's also much more full-body because the core and arms become involved when I stand and sprint, or if I try to simulate pro riders' aero positions. But, yes, it still doesn't approach the XC ski machine or Air-Dyne (or even a Concept2 rower) for maximum muscle use.

    None of which remotely approaches the intensity of a limit 5-set of squats or deadlifts.
    2828 days ago
  • JADOMB
    Thanks, I'm always learning more. Who says you can't teach and old dog new tricks. ;-)
    2833 days ago
  • ROSINVN
    Interesting. I have this dilemma too, as the spark count is one think, the machine count is another and I have a heart rate monitor and it gives me a third figure all highly different. Not sure which one to believe as i am on BP medicine that affects the heart rate which probably why the monitor gives me such very low cal burn readings, or maybe its true? who knows?

    2840 days ago
  • HOLLYBERRY005
    Interesting!
    2841 days ago
  • NANCYANNE55
    Very interesting! I wasn't aware that Sparks calculator took the individuals weight into consideration at all- I assumed it thought we all were 150 lb females. And even at that, I thought the calories burned was too high.

    Thank you for taking the time to do this.
    2842 days ago
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    Disclaimer: Weight loss results will vary from person to person. No individual result should be seen as a typical result of following the SparkPeople program.
 

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