Avg Power From Run Analysis

[Fasterhorses]

I zipped down the tcx file and attached it. I hope I did it right because it does not show in the preview window.

This is a bike run, not mine, that I put into TopoFusion, Run Analysis, used 80kg for weight and got average power of 655w and gain of 4396 ft. Then I corrected the elevations and got a gain of 6827 ft.

That gain correction does not seem right. Also I do not understand the power number. Someone told me that 655w was nonsense. Am I using the program incorrectly or what? Thanks for any help.

Don Huston

[ScottMorris]

I can take a look at your file, but I just want to make sure you know that Run Analysis tools are for  foot running.  If you plug a bike ride into it, you will get impossibly high power numbers because it is assuming you ran that fast.

As for the gain, I looked at the file and 4200 seems reasonable for that ride.  You are right that it goes up when corrected.  Not sure why right now.

In general it is not possible to accurate generate power numbers for bike riding, after the fact.  The problem?  Coasting.

With running (or horse riding) there is no coasting -- you are always doing work if moving.  Not so on a bike.  So equations for run/horse do not apply to bicycling.

[Fasterhorses]

Thank you Scott.
So then the calories are also not correct for a bike run?
I have been recommending TopoFusion to some bike riders. Is there a way for them to use TF?
It is working great for training my horse.

Don Huston

[ScottMorris]

Yes, the calories would be off if you fed a bike ride into "run analysis."  

There is a lot TF can do for bike riders!  I'm one.    No software can compute power numbers for a bike ride based on a GPS track, though.  It's just not possible. 

But if someone does have a power meter, there is a bunch of stuff TF can do with that power data.  It's just not in "run analysis."  Read this page for more about using power in TF:

http://topofusion.com/power.php

And of course all the other cycling related functions...

[Fasterhorses]

Thanks for clearing up that mess I made on the Garmin forum with those power numbers. I really have no concept for power since I am not the athlete, my horse is. 

That gain upward adjustment on that bike track was strange. All my tracks with my 705 recorded on the horse always adjust down, less gain.

Don Huston

[ScottMorris]

On some mountain roads the elevation correction can make the gain go up.  E.G. heavily cut in roads, or if the road ride goes across a lot of bridges -- it will give you credit for dropping into the canyon and climbing back out.

So, the elevation correction is a lot more reliable for trails than (major paved) roads.