How do cycle computers calculate calories / cadence, etc.

General
1

I don’t care so much about how the calculation is reached. I care more about whether that calculation is valid for unicycles.

I’ve been using the iPhone app “Cyclemeter”, which uses GPS positioning to calculate speed, distance and plots a map of your ride. If you provide your weight, it also calculates calories burned.

But, if the app assumes I’m bicycling, is that calculation valid? How does it come up with that number?

Also, if I get some of the neat toys from Wahoo (or similar), I could track heart rate, cadence, and a more accurate gauge of speed. I understand heart rate and speed. But does cadence translate on a uni? How about a Schlumpf?

My guess for cadence is that you’ll get a set of numbers that look different from a bike at similar speeds. But as long as you are tracking against yourself and possibly other unicyclists, it can still be a valid way of tracking your performance.

I want to acknowledge that stuff like this, at least for me, is 50% about improving my performance and 50% about playing with toys.

http://www.wahoofitness.com/Products/Products.asp

-------Stats from my most recent ride. Cadence and heart rate are zero because I dont have the toys-------

Route: New Route
Activity: Cycle
Started: Aug 30, 2012 5:05:55 PM
Ride Time: 1:32:04
Stopped Time: 0:00
Distance: 16.94 miles
Average Speed: 11.04 mph
Fastest Speed: 14.31 mph
Ascent: 174 feet
Descent: 257 feet
Calories: 839
Average Heart Rate: 0 bpm
Maximum Heart Rate: 0 bpm
Average Cadence: 0 rpm
Maximum Cadence: 0 rpm

2

Nick-

You can’t have it both ways.

I think that the calculation is probably invalid for both a bicycle and a unicycle. There is far too much that is not taken into consideration even for the case of a bike. It doesn’t know about wind speed or wind direction. It doesn’t know about rider posture. It can’t possibly know about the rider’s metabolism.

3

Well, I don’t really care about how the calculation is done. But if it helps me understand whether the result is valid, then I’m interested. :slight_smile:

I guess it’s all about margin of error. Clearly, whatever math it’s doing is a gross oversimplification. But I’m wondering if the accuracy is the same between bike and unicycle. Or, is it “kind of accurate” for bikes while being “not even close” for unicyclists.

Is the general consensus that those calculations aren’t worth looking at to begin with? I can’t really see why cadence is important, but getting a general idea of calories burned on a ride could come in handy.