Precor Elliptical: Watts vs Cyclist's?

I've started doing 1-hour sessions on Precor's 100i elliptical
machine.

http://www.bodyconcept.com/family/6133/display.html

I'm using "Calories Per Minute" to measure myself.

Currently, my cruising speed seems tb about 17 calories per
minute or 1020 calories per hour.

But the conversion factor to watts that I see is 860 calories per
hour (859.8452), which gives me an output in watts of a little
under 1.2. (1.1816) http://tinyurl.com/2x3833


My understanding is that competitive cyclists put out from 150 to
300 watts.

1.2...... 150.... seems like an awfully big diff.

Am I calculating something incorrectly? Maybe dropping a
decimal point....

Or is my capacity really that pitiful?
--
PeteCresswell

"(PeteCresswell)" writes:

1.2...... 150.... seems like an awfully big diff.

Am I calculating something incorrectly? Maybe dropping a
decimal point....

Probably your machine's "calories" are actually kilocalories whereas
your conversion uses actual calories which would make the result off
by a factor of 1000. Then again, 1200 W sounds superhuman for a
long-term effort, so I would guess that it displays something the
energy you consume rather the energy that would be used for locomotion
(making the comparable figure something between 240 W and 300 W), or
that the meter just shows some random numbers with some positive
correlation to actual energy expenditure (I have had one piece of
fitness equipment with such a feature).

"(PeteCresswell)" wrote in message
...
I've started doing 1-hour sessions on Precor's 100i elliptical
machine.

http://www.bodyconcept.com/family/6133/display.html

I'm using "Calories Per Minute" to measure myself.

Currently, my cruising speed seems tb about 17 calories per
minute or 1020 calories per hour.

But the conversion factor to watts that I see is 860 calories per
hour (859.8452), which gives me an output in watts of a little
under 1.2. (1.1816) http://tinyurl.com/2x3833


My understanding is that competitive cyclists put out from 150 to
300 watts.

1.2...... 150.... seems like an awfully big diff.

Am I calculating something incorrectly? Maybe dropping a
decimal point....

Or is my capacity really that pitiful?
--
PeteCresswell

3 things, 1.2 should be 1200w (kilocalories v calories) and the numbers
quoted for your burn rate assume a 25% efficiency. That is, your actual
useable output would be 1200/4 = 300 watts. These machines are usally
pitifully inaccurate. 300 watts for cruising should see you with a pro
contract :-)

Phil H



Phil H

Per Phil Holman:
3 things, 1.2 should be 1200w (kilocalories v calories) and the numbers
quoted for your burn rate assume a 25% efficiency. That is, your actual
useable output would be 1200/4 = 300 watts. These machines are usally
pitifully inaccurate. 300 watts for cruising should see you with a pro
contract :-)

So... suspicions confirmed: No actual relationship to reality....

The big thing to me is that it's repeatable and, maybe,
comparable (i.e. I can sneak a glance at the guy next to me and
see how I'm doing compared to him....)

But I suspect that even the "comparable" aspect is suspect. Seems
to me like I can game the system - higher resistance settings
produce higher calorie readings with less perceived effort than
lower settings. And, of course, a lot of people just hop on the
thing and start booking - without punching in their body
weight.... so they're getting artificially low readings unless
they're quite light.
--
PeteCresswell