INTRODUCTION: Over a century ago the Douglas Bag method was introduced for determining the respiratory exchange in human (Douglas, 1911). Although many types of electronic measurement systems have been introduced since, the Douglas Bag method is still considered as the Golden Standard for this type of measurements. The aim of this work was to create a portable Douglas Bag system for use in, for example, measuring the oxygen uptake of cross-country skiers. METHOD: The Douglas Bag (120 L) was made of PU coated fabric and equipped with ball valve and a sampling tube for measurement of gas concentrations (C Fritze Consulting, Svedala, Sweden). The Bag was mounted on the back of the subject on a carrying system (modified back protector made for alpine skiing) with a simple coupling that makes it possible to easily switch between different bags. The system has a three-way valve placed on the athletes chest, specially designed for the system and 3D-printed in ABS material (uPRINT SE PLUS, Stratasys, USA) and a timer to measure the sampling sequence. The system uses the same type of hoses and breathing valve as used for electronic systems. The complete system weighs 2.7 kg, which is less than a Biathlon rifle. Step 1. Before the sampling starts the exhaled air flows through the three-way valve and into the atmosphere. Step 2. By pushing the valve into the sampling position the timer starts and the exhaled air is directed into the Douglas Bag. Step 3. The valve is pushed back in the first position, shuts off the flow to Douglas Bag and stop the timer. RESULTS: Figure 1 shows a cross-country skier during a testing session with the portable Douglas Bag system. DISCUSSION: The portable Douglas Bag system has been tested for cross-country skiers during roller skiing and skiing on snow in order to determine maximal oxygen uptake. These tests show that the skiers experiencing system easy to carry and that it does not hinder them in their performance. CONCLUSION: The portable Douglas Bag system can be used for collection of expiratory gases both in the field and in the laboratory. The system is particularly well suited for activities such as walking, Nordic walking, running and cross-country skiing. ACKNOWLEDGEMENT: The authors would like to thank Peak Innovation and the European Union´s regional development fund, which provided financial support for this project. --- The hosting University of Jyväskylä is planning to publish conference proceedings "Science and Nordic Skiing III". In case you are interested in this publication please contact the editors (Anni Hakkarainen anni.s.j.hakkarainen@jyu.fi) to become registered for the book.
© Copyright 2015 3rd International Congress on Science and Nordic Skiing - ICSNS 2015. 5-8 June 2015, Vuokatti, Finland. Veröffentlicht von University of Jyväskylä; University of Salzburg. Alle Rechte vorbehalten. / Übersetzt mit https://www.DeepL.com/Translator