Abstract
The aim of this study was to validate a computerized metabolic system with mixing
chamber (Oxycon Pro, Erich Jaeger GmbH, Hoechberg, Germany) against the Douglas bag
method (1) over a large range of ventilations and (2) for drift during shorter (25-min
time trial) and longer (∼ three months) test periods. Eighteen well-trained/elite
cyclists performed graded exercise tests, maximal oxygen uptake tests and time trial
tests on an electromagnetic braked cycle ergometer. Respiratory variables were measured
simultaneously, once or several times in every test by the Oxycon Pro and the Douglas
bag method. (1) Overall, oxygen uptake was 0.8 % (0.03 l · min-1) lower with the Oxycon Pro than with the Douglas bag method with a coefficient of
variation of 1.2 % (n = 802) (p < 0.05). (2) During the time trials, oxygen uptake
measured with the Oxycon Pro gradually decreased from 0.5 % (0.02 l) lower than the
Douglas bag method at 5 min to 1.0 % (0.05 l) lower at 25 min (p < 0.05). Over the
period of three months of testing, oxygen uptake measured with the Oxycon Pro gradually
increased from 1.1 % (0.04 l) lower than the Douglas bag method at the start to 0.5
% (0.02 l) lower at the end (p < 0.05). This study demonstrates that a computerized
metabolic system with mixing chamber is an accurate system for measuring oxygen uptake.
This applies to testing over a large range of ventilations and for stability both
during shorter and longer test periods.
Key words
Oxycon Pro - Douglas bag method - reproducibility - drift
- 1
Bassett Jr D R, Howley E T, Thompson D L, King G A, Strath S J, Mclaughlin J E, Parr B B.
Validity of inspiratory and expiratory methods of measuring gas exchange with a computerized
system.
J Appl Physiol.
2001;
91
218-224
- 2
Beaver W L, Wasserman K, Whipp B J.
On-line computer analysis and breath-by-breath graphical display of exercise function
tests.
J Appl Physiol.
1973;
34
128-132
- 3
Bland J M, Altman D G.
Statistical methods for assessing agreement between two methods of clinical measurement.
Lancet.
1986;
1
307-310
- 4
Carter J, Jeukendrup A E.
Validity and reliability of three commercially available breath-by-breath respiratory
systems.
Eur J Appl Physiol.
2002;
86
435-441
- 11
Foss Ø, Hallén J.
The most economical cadence increases with increasing workload.
Eur J Appl Physiol.
2004;
92
443-451
- 5
Gore C J, Clark R J, Shipp N J, van der Ploeg G E, Withers R T.
CPX/D underestimates V·O2 in athletes compared with an automated Douglas bag system.
Med Sci Sports Exerc.
2003;
35
1341-1347
- 6
Jentjens R L, Moseley L, Waring R H, Harding L K, Jeukendrup A E.
Oxidation of combined ingestion of glucose and fructose during exercise.
J Appl Physiol.
2004;
96
1277-1284
- 7
Proctor D N, Beck K C.
Delay time adjustments to minimize errors in breath-by-breath measurement of V·O2 during exercise.
J Appl Physiol.
1996;
81
2495-2499
- 8
Rietjens G J, Kuipers H, Kester A D, Keizer H A.
Validation of a computerized metabolic measurement system (Oxycon-Pro) during low
and high intensity exercise.
Int J Sports Med.
2001;
22
291-294
- 9
Salminen R, Aunola S, Malkia E, Vuori I.
Computerized breath-by-breath analysis of respiratory variables during exercise.
Med Prog Technol.
1982;
9
27-32
Jostein Hallén
Norwegian University of Sport and Physical Education
PO Box 4014, Ullevål Stadion
0806 Oslo
Norway
Phone: + 4723262314
Fax: + 47 23 26 24 51
Email: jostein.hallen@nih.no
