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slitzenberger69
01-15-2007, 06:48 PM
Dear all!
Though it has been a while ago - here are the summarized responses to my
question:

> Dear all!
>
> being absolutely new on the subject of ergospirometric measurements, i
> was wondering whether it is possible to calculate the inner power
> production of a subject and thus being able to reliably calculate the
> human efficiency (mechanical power (e.g. cycle-ergometer) vs inner
> power production).
>
> Literature I´ve cross-read so far speaks of an average 5 kcal/l O2,
> (5,1 for carbohydrates, and 4,6 for fat).
>
> Maybe you could suggest some literature where my questions will be
> answered.
>
> Thanks for your help
>
> regards from Vienna
> stefan

Thank you for your contribution and help it is highly appreciated.

regards from Vienna

stefan
------------------------------------
replies:

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Merel Brehm, VU medisch centrum, Amsterdam:

Innner power production can be calculated by measuring metabolic oxygen
consumption and carbon dioxide production (VO2 and VCO2).I guess, in
your particular matter, during riding on a cylce ergometer, but it can
also be measured during walking. This can be done by using stationairy
or portable gas-analysis sytems. From the measurements, energy
expenditure can be calculated by taking into account the relative
contributions of carbohydrates (5.1) and lipids (4.6), denoted by the
respiratory exchange ratio (RER). (ref 1)

I shall add some references which micht be usefull for you:

1) Garby L, Astrup A. The relationship between the respiratory quotient
and the energy equivalent of oxygen during simultaneous glucose and
lipid oxidation and lipogenesis. Acta Physiol Scand 1987; 129: 443–4.

2) Brehm MA, Harlaar J, Groepenhoff H. The validation of the portable
VmaxST system for oxygen-uptake measurement. Gait Posture 2004; 20: 67-73.

3) Brehm MA, Nollet F, Harlaar J. The energy demands of walking in
individuals with postpoliomyelitis syndrome: relationship with muscle
strength and reproducibility Arch Phys Med Rehabil 2006; 87: 136-40.
----------

ir. P. de Jong, TNO Industrie&Techniek, 5600 HE Eindhoven (NL):

Helpful article in this:
Umberger et al: A model of human muscel energy expenditure, computational methods biomech, biomed, engin, 2003, 6(2), 99-111

Bhargava et al. a phenomenological model for estimatin gmetabolic energy consumption in muscle contraction, j biomech, 2004, 37(1), 81-88
----------
Rodger Kram, Univ. of Colorado, Boulder, CO 80309-0354

try George Brooks textbook, Exercise Physiology.
i prefer 20.1 J/mlO2
kcal are a rather ancient unit.
----------
Andrew Sims, PhD student, University of New South Wales

I found the following useful (it is translated from the French

from memory)
Amar, J., The Human Motor or The Scientific Foundations of Labour and
Industry. 1920, George Routeledge & Sons Ltd: London.
-----------

Ted Andresen, St. Petersburg, Florida
I have two leads that may help you. One is a "wattage"
group that recently moved to Google.
http://groups-beta.google.com/group/wattage This is a discussion group
for cyclists who train with power meters. There are a few researchers in
the group that may be able to help you. The other lead is a paper by
Lance Armstrong's doctor, Edward F. Coyle, titled
Improved Muscular Efficiency Displayed As Tour De France Champion Matures
J. Appl Physiol 98: 2191–2196, 2005
------------

J.Paul. MICALLEF, Directeur de Recherche INSERM, Montpellier
See at
http://jeanfrederic.brun.free.fr/antonia_substrats.pdf and
http://jeanfrederic.brun.free.fr/

and in pubmed at Brun JF, Mercier J,
Metabolism. 2005

Nov;54(11):1411-9.
Substrate oxidation during exercise at moderate and
hard intensity in middle-aged and young athletes vs sedentary men.*
*

-----------
Todd Carver, Biomechanics Laboratory, Boulder Center for Sports Medicine

What you are looking for is a chart of caloric equivalents and RER
values. The RER is the respiratory exchange ratio and is the ratio between
oxygen consumption and carbon dioxide production. You cannot just go off of
fat and carbohydrates. You need to convert according to the RER. If you
just want to assume a mixed fuel usage, you can use an RER of 0.85, which I
beleive gives you a caloric conversion factor of 4.82 kcal/L O2
-----------

Randall Jensen, PhD, FACSM, Dept. Health Physical Education &
Recreation, Northern Michigan

In addition to what the foodstuff is, whether the energy is from aerobic
or anaerobic sources also might make a difference. Thus if the intensity
is high and the energy source mainly anaerobic, the cost may be
underestimated. Most studies avoid anaerobic levels, by keeping the
intensity low (below lactate threshold or Onset of Blood Lactate
Accumulation, also known as OBLA) but, for some types of exercise that
is not possible.

I’ve attached a paper that I published that has some references
referring to that problem and how to deal with it. In particular the
ones by Cerrelli & Binzoni, 1990; Margaria et al., 1963; and di Prampero
et al., 1971 may be of interest. Also the papers by di Prampero, 1981
and Gladden & Welch; 1978 might be helpful as they speak to efficiency
in more general terms and for different types of activity (the former
especially). ------------------

---

DI (FH) Stefan Litzenberger
Fachhochschule Technikum Wien
University of Applied Sciences
Sportgerätetechnik / Sports Equipment Technology
Höchstädtplatz 5
A-1200 Vienna
Austria
Tel: ++43 1 3334077 - 377
Fax: ++43 1 3334077 - 369
mailto:litzenberger@technikum-wien.at