"The calories are now calculated based on the following data: body
measurements (height, weight, age, gender), sport, distance, time, speed and
heart rate. The more data you provide the more accurate we can calculate
your calories burned.
The calculation methods are based on CPA: ‘The compendium of physical activity’
http://sites.google.com/site/compendi.. .
and Keytel LR, Goedecke JH, Noakes TD, Hiiloskorpi H, Laukkanen R, van der Merwe L, Lambert
EV. Prediction of energy expenditure from heart rate monitoring during
submaximal exercise. J Sports Sci. 2005 Mar;23(3):289-97. PubMed PMID:
15966347. "
measurements (height, weight, age, gender), sport, distance, time, speed and
heart rate. The more data you provide the more accurate we can calculate
your calories burned.
The calculation methods are based on CPA: ‘The compendium of physical activity’
http://sites.google.com/site/compendi.. .
and Keytel LR, Goedecke JH, Noakes TD, Hiiloskorpi H, Laukkanen R, van der Merwe L, Lambert
EV. Prediction of energy expenditure from heart rate monitoring during
submaximal exercise. J Sports Sci. 2005 Mar;23(3):289-97. PubMed PMID:
15966347. "
The google sites link is broken. Here's the info on the cited exercise study:
Abstract here: http://www.ncbi.nlm.nih.gov/pubmed/15966347
Uh oh- Endomondo isn't using the results of this study precisely. The title says: "Prediction of energy expenditure from heart rate monitoring during submaximal exercise." It does not say "Prediction of energy expenditure from height, weight, age, gender, sport, distance, time, speed and heart rate." But that's what Endo says they are doing.
Oh! I just found the correct site for "The compendium of physical activity." Here it is: https://sites.google.com/site/compendiumofphysicalactivities/
So, for running at 7 mph (8.5 min/mile), activity code 12070. The MET equivalent is.... 11.0 MET. What in the world is a MET? Um... the ratio of work metabolic rate to resting metabolic rate. Sitting quietly has a rate of 1 MET (1 kcal/kg/hr). While running at 8.5 min/mile is 11 kcal/kg/hr. So running burns 11 times as much energy per hour as sitting quietly. Here comes the next calculation:
MET * (weight in lbs/2.2) * (minutes + seconds/60)/60 per hour = 11.0 * (200/2.2) * (41 + 39/60)/60 = Drumroll please........ Louder, Drumroll please.....
694 calories for Thursday's run. (But now that I have a handy chart with MET equivalents, I can just compare the MET for running to the MET for cycling.)
The MET for cycling, activity code 01040, at 15 mph (Friday's workout) is 10.0 kcal/kg/hr. But I wasn't exactly cycling, I was riding a mountain bike with knobby tires on an asphalt trail. So maybe it was a bit more, maybe, say, 10% more difficult than regular cycling, so the MET is somewhere around 11.0. That seems familiar, like that was the same MET equivalent for... Thursday's run.
So can I just say right now that using all of these tables and equivalents and such is much less precise than I would expect? There must be an easier way to do this. I guess I need to find a copy of the Keytal et al. article and see what it says. On we go...
You've done some research, which is more than I care to (other than read your research of course!) :)
ReplyDeleteThe thing is, i'm pretty sure that a fit person isn't just fitter, but their muscles and efficiency of doing a excercise movement is itself using less energy. So, lets say two people are just as fit as each other at say rowing, but one does running, the other does cycling as their seconds sports, and ceteris paribus, you might find that there actual outputs differ? (Iow, at the same weight, same heart rate, and they are twins, you might find one is going faster in cycling than the other, even though in rowing they are identical, meaning their energy burnt is different? Or is it... I dont know)