REPRODUCIBILITY OF AN INCREMENTAL TREADMILL _ VO 2 MAX TEST WITH GAS EXCHANGE ANALYSIS FOR RUNNERS THIAGO FERNANDO LOURENC xO, 1 LUIZ EDUARDO BARRETO MARTINS, 2 LUCAS SAMUEL TESSUTTI, 1 RENE BRENZIKOFER, 3 AND DENISE VAZ MACEDO 1 1 Laboratory of Exercise Biochemistry (LABEX), Biochemistry Department, Biology Institute, State University of Campinas-UNICAMP, Campinas, Sa˜o Paulo, Brazil; 2 Laboratory of Instrumentation for Physiology, Faculty of Physical Education (FEF), State University of Campinas-UNICAMP, Campinas, Sa˜o Paulo, Brazil; and 3 Laboratory of Instrumentation for Biomechanics (LIB), Faculty of Physical Education (FEF), State University of Campinas-UNICAMP, Campinas, Sa˜o Paulo, Brazil ABSTRACT Lourenc xo, TF, Martins, LEB, Tessutti, LS, Brenzikofer, R, and Vaz Macedo, D. Reproducibility of an incremental treadmill _ VO 2 max test with gas exchange analysis for runners. J Strength Cond Res 25(7): 1994–1999, 2011—The evaluation of perfor- mance through the application of adequate physical tests during a sportive season may be a useful tool to evaluate training adaptations and determine training intensities. For runners, treadmill incremental _ VO 2 max tests with gas exchange analysis have been widely used to determine maximal and submaximal parameters such as the ventilatory threshold (VT) and respiratory compensation point (RCP) running speed. However, these tests often differ in methodological character- istics (e.g., stage duration, grade, and speed increment size), and few studies have examined the reproducibility of their protocol. Therefore, the aim of this study was to verify the reproducibility and determine the running speeds related to maximal and submaximal parameters of a specific incremental maximum effort treadmill protocol for amateur runners. Eleven amateur male runners underwent 4 repetitions of the protocol (25-second stages, each increasing by 0.3 kmÁh 21 in running speed while the treadmill grade remained fixed at 1%) after 3 minutes of warm-up at 8–8.5 kmÁh 21 . We found no significant differences in any of the analyzed parameters, including VT, RCP, and _ VO 2 max during the 4 repetitions (p . 0.05). Further, the results related to running speed showed high within-subject reproducibility (coefficient of variation , 5.2%). The typical error (TE) values for running speed related to VT (TE = 0.62 kmÁh 21 ), RCP (TE = 0.35 kmÁh 21 ), and _ VO 2 max (TE = 0.43 kmÁh 21 ) indicated high sensitivity and reproducibility of this protocol. We conclude that this _ VO 2 max protocol facilitates a clear determination of the running speeds related to VT, RCP, and _ VO 2 max and has the potential to enable the evaluation of small training effects on maximal and submaximal parameters. KEY WORDS ventilatory threshold, respiratory compensation point, physical evaluation, maximal effort protocol, running INTRODUCTION T he main adaptation to endurance training is an increased oxidative capacity because of mitochon- drial biogenesis and increased fatty acid use as fuel (13). Evaluating performance through the applica- tion of adequate physical tests during a sportive season may be a useful tool to indirectly evaluate these training adaptations and also for the prescription of training intensities (11). Treadmill incremental _ VO 2 max tests with gas exchange analysis have been widely used during training programs for runners to evaluate program effects and to determine target intensities. However, these tests often differ in their methodological characteristics, such as stage duration, grade, and speed increment size (1,2,10,20,23). Even with the availability of treadmills with computational speed control, classical protocols using grade variations to adjust exercise intensity during tests are still commonly used and can hinder the practical application of laboratory information (20). To be applicable for runners, a _ VO 2 max test protocol should approximate actual training and outdoor race conditions to unequivocally determine maximal (and also submaximal) parameters such as the ventilatory threshold (VT) and respiratory compensation point (RCP). Determining the speeds related to these parameters facilitates the definition of 3 exercise intensity domains for training prescription: moderate (below VT), heavy (between VT and RCP), and severe (above RCP) (2,20,25). Previous studies have shown that speeds related to VT (sVT) and _ VO 2 max (s _ VO 2 max) can Address correspondence to Denise V. de Macedo, labex@unicamp.br. 25(7)/1994–1999 Journal of Strength and Conditioning Research Ó 2011 National Strength and Conditioning Association 1994 Journal of Strength and Conditioning Research the TM Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited.