## 4 Discussion  
The results of the present study confirm the hypothesis that soccer players with visual impairment have higher VO\({}_{\text{2 max}}\) than nonathletes. Also, the second hypothesis was confirmed, as no correlation of VO\({}_{\text{2 max}}\) with the running performance of the players in the matches was observed. Relationship of VO\({}_{\text{2 max}}\) with Total Match Running Distance and Other Physiological Parameters  
This is the only study that investigates the relation of VO\({}_{\text{2 max}}\) to the distance covered during a soccer match for people with visual impairment. The findings showed that there were no correlations with the total running distance covered in soccer matches by athletes. In the literature, there is no study to compare with this study's findings in soccer players with visual impairment (about the correlation between VO\({}_{\text{2 max}}\) and match running performance). However, in a study performed on soccer players without visual impairment [12] that tested the relationship between VO\({}_{\text{2 max}}\) and match running performance (measured by GPS), no correlations were mentioned. At all levels and kinds of soccer matches, the tactical role, individual playing position, opponent and stimulus degree of motivation can affect the correlation between VO\({}_{\text{2 max}}\) and match running performance. It has been shown that some contextual variables can affect external load, such as match running distance [6]. However, [PERSON] et al., (2020) [22] in a tournament for individuals with visual impairment showed a similar match running distance (1416 to 1877 m). The position played by the players and the tactics applied by the team affect not only the distance covered by the players but also the characteristics of these distances. For example, it is well known that lateral midfielders perform more and bigger sprints than central midfielders. In soccer players without visual impairment, the values of VO\({}_{\text{2 max}}\) are between 55 and 65 mL/kg/min [23]. These values are high since players must be able to cope with the demands of the sport, but they are not like the values in endurance sports that exceed 70 mL/kg/min [24]. Coaches do not seek to maximize VO\({}_{\text{2 max}}\) as they prefer to devote the time they would spend for this purpose to training technical-tactical elements. Additionally, no correlations were observed between VO\({}_{\text{2 max}}\) and other physiological parameters like heart rate or median and maximum velocity of the players during a soccer match. However, a study by [PERSON], et al. (2020) [22] on soccer players with visual impairment from three different countries (Spain, Italy and Czech Republic) showed lower heart rate average values (-145 beats/min) during matches than the present study. Similar results were presented in a more recent study by the same laboratory [6] that was performed \begin{table}
\begin{tabular}{c c c c c c c c c} \hline  & \multicolumn{3}{c}{**Soccer Players**} & \multicolumn{3}{c}{**Sedentary People**} & \\  & \multicolumn{3}{c}{**Percentiles**} & \multicolumn{3}{c}{**Percentiles**} & \\  & **Median** & **25 th** & **75 th** & **Median** & **25 th** & **75 th** & **\(p\)** & \(\eta^{2}\) \\ \hline HRmax (b/min) & 161 & 144 & 186 & 162 & 147 & 176 & 0.995 & \(<\)0.001 \\ RER & 1.05 & 1.00 & 1.10 & 1.05 & 0.98 & 1.10 & 0.841 & \(<\)0.001 \\ VO\({}_{\text{2 max}}\) (L/min) & 2.90 & 2.63 & 3.17 & 2.77 & 2.60 & 3.05 & 0.157 & 0.149 \\ VO\({}_{\text{2 max}}\) (mL/kg/min) & 41.15 & 36.93 & 43.93 & 33.95 & 30.18 & 41.78 & 0.002 & 0.755 \\ Relative to body mass & & & & & & & & \\ VO\({}_{\text{2 max}}\) (mL/kg/min) & 51.06 & 47.48 & 55.29 & 44.97 & 41.82 & 51.66 & 0.004 & 0.674 \\ Relative to lean body mass & & & & & & & & \\ \hline \end{tabular}  
* Level of significance \(p\) \(<\) 0.05; \(\eta^{2}\)—partial eta square; partial eta squared classification as small (0.01 to 0.058), medium (0.059 to 0.137) or large (0.138 or higher).  
\end{table} 
Table 3: The values of participants’ cardiorespiratory parameters.