@article{Stefanov_2022, title={Comparison between determination of second anaerobic threshold by respiratory compensating point and X-method in rowers}, volume={26}, url={https://sportpedagogy.org.ua/index.php/ppcs/article/view/1884}, DOI={10.15561/26649837.2022.0204}, abstractNote={<p><em>Background and Study Aim.</em> The aim of this study is to verify the X-method for determining the second anaerobic threshold in rowers.<br><em>Material and Methods.</em> Twelve male athletes from the national rowing team of Bulgaria were tested. Participants performed a one-time graded incremental exercise test to exhaustion on a rowing ergometer. The workload were conducted on rowing ergometer system Concept 2, and spirometry system Clark C5. We obtained ventilatory indices, intensity and heart rate bred-by-bred for each participant, for each test stage. The anaerobic threshold was determined by two methods: 1) by the localization of the respiratory compensation point visually, after polynomial regression analysis of the trends for the dynamics of the ventilatory variables related to time and 2) by the X-method using the change in the ratio between heart rate and pulmonary ventilation. We compared the heart rate corresponding to the anaerobic threshold determined by both methods.<br><em>Results</em>. We found similar values for heart rate at the respiratory compensation point and the anaerobic threshold determined by the X-method for each of the investigated. The Shapiro-Wilk test showed a normal distribution of the two samples with a significance level of α = 0.05. Thus, the t-test for two paired samples showed a p-value of 0.202 at α = 0.05. We found a correlation coefficient r = 0.973 between the heart rate at the anaerobic threshold (determined by X-method) and the heart rate at the anaerobic threshold (detected at the respiratory compensation point). The Blant-Altman analysis showed that 95% of the points in the scatter plot lie within the confidence interval.<br><em>Conclusions</em>. The two methods give similar results and can be applied alternatively in the investigation of rowers in the age group 18.3 ± 1.07 years. The X-method always gives a reliable intersection point, which in our studies is close to the second anaerobic threshold. Comparative studies are also needed in other contingents for the wider use of the X-method.</p>}, number={2}, journal={Pedagogy of Physical Culture and Sports}, author={Stefanov, Lachezar G.}, year={2022}, month={Apr.}, pages={101–110} }