2011/8/15 skew 41 <ske...@googlemail.com>
>
> > for the MET depending for example on speed and incline (and these can be
>> > calculated from the GPS data). A quick search provided this:
>> > http://www.exrx.net/Calculators/WalkRunMETs.html
>> >
>> > This calculator demonstrates also that MET depends on speed and incline
>> > (grade).
>> >
>> > There is no formula written there, but it can be derived from the
>> JavaScript
>> > code. I did not check the references he provides. Maybe a formula can be
>> > found there.
>>
>> It would be great if you can provide mentioned formula.
>>
> I could. But there are some coefficients, which I do not know what they
> mean. Probably they are related to different systems of units (miles/km,
> etc.). If not really understanding such a formula, I would prefer not to
> introduce it into a software. I propose to ask the author of this website
> for a reference.
>
I think the formula is just a linear interpolation of some known values. At
least I do not see any other reason for the coefficients to be like this.
Here is a function calculating MET for running:
def met_running(SpeedValue, Grade, NG):
SpeedUnit=16.6666 # if speed is given as km/h
#SpeedUnit=1 # if speed is given as m/min
Speed=SpeedValue*SpeedUnit
#NG=0 # 0 for new, 3.5 for gross
#FWVO= 21.11 - 0.3593 * Speed + 0.0030 * Speed * Speed + 0.018 * Grade *
Speed - 3.5 + NG
RVO= 0.2 * Speed + 0.009 * Grade * Speed + NG
MET = RVO/3.5
return MET
Using the following conversion function, we can illustrate this:
def mph2kmh(mph):
return mph*1.60934
for mph in [4 .. 14]:
print mph, "\t", mph2kmh(mph), "\t", met_running(mph2kmh(mph), 0, 0)
The result is:
mph MET
4 6.13079452434286
5 7.66349315542857
6 9.19619178651429
7 10.7288904176000
8 12.2615890486857
9 13.7942876797714
10 15.3269863108571
11 16.8596849419429
12 18.3923835730286
13 19.9250822041143
14 21.4577808352000
For comparison, the values given at
https://sites.google.com/site/compendiumofphysicalactivities/Activity-Categories/running
are:
mph MET
*4 6.0
5 8.3
**6 9.8
**7 11.0
**8 11.8
**9 12.8
**10 14.5
**11 16.0
**12 19.0
**13 19.8
**14 23.0
There are differences, but roughly they coincide. Since two different
sources provide similar values, I guess one can believe roughly in
these values.
Note that the above calculation is done with NG=0, which corresponds
to "net" on the form of the website. I am not sure what this means.
Please note the following line from
http://www.exrx.net/Calculators/walkrunmets.js
*<!-- Do not copy any part of this script without permission; James T.
Griffing, MS, BS; http://www.exrx.net //--><!--
One should contact the author before implementing this in pytrainer.
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