## 4 Discussion
Among the players classified according to the previous classification system (C5/6-C8) there are significant differences between sport classes regarding the total distance covered in absolute terms, the same as occurs with the players classified according to the current system (FT1-FT3) with respect to the total distance covered in relative terms. These differences between sport classes could occur because C5/6, FT5/6, and FT1, regardless of the classification system used, are the sport classes with the greatest physical impairments to move due to diplegic, hemiplegia, ataxia, athetosis, dyskinesia or dystonia, unlike C8, FT8, and FT3, which are the sport classes with the least physical impairment and the greatest locomotion capacity. In relation to the distance covered in different speed ranges in absolute terms, only one study included in this review analyzes these variables dividing the sample by sport class [28]. The results showed that C8 players covered more distance above 23.04 km\(\cdot\)h\({}^{-1}\). Considering the correlation between the distance covered at high speeds and the effectiveness of attacking moves during the match [40], it appears that being able to go a greater distance at these speeds helps players become more competent in-game. On the other hand, an analysis of the distances covered at different speeds shows a disparity in the results obtained in relative terms [41]. While some studies show a relationship between the distance covered at high speeds and the degree of physical impairment of para-footballers [28], others show no such results [29; 31; 32]. The establishment of arbitrary values for the speed ranges may have influenced the results obtained by the different studies [42]. More studies are needed using individualized ranges in CP footballers, which allow us to obtain a clearer vision of the activity levels of the players in all-time motion analysis studies using GPS devices as occurs in conventional football [43]. To our knowledge, only the study of [PERSON] et al. [35] analyzed match responses in para-footballers using individualized thresholds, i.e., below 25%, between 25 and 50%, between 50 and 70%, between 70 and 90%, and above 90% of maximum speed. In addition to the relevance of recording the distance covered at high speeds, it is also necessary to pay attention to the maximum speed achieved by the players, since one of the most frequent actions preceded by goal situations in soccer is the sprint [44]. In the studies included in this review, the maximum speed values were 27.86 \(\pm\) 1.22 km\(\cdot\)h\({}^{-1}\). Previous studies have indicated that as the level of physical impairment decrease (i.e., C8, FT8, or FT3, depending on the classification system in force at the time of each investigation), maximum speed values tend to be higher [27; 30; 31]. This variable in football is closely associated with physical and locomotor performance [43; 45]. Therefore, players with less motor impairment are likely to generate force more efficiently and move at faster speeds. The intermittent nature of PC football underscores the importance of short-term high-intensity actions, such as accelerations, decelerations and change of direction [46; 47]. The intensity zones for the accelerations and decelerations are arbitrary and vary de pending on the authors. Different ranges have been proposed, including 1-2 m\(\cdot\)s\({}^{-2}\)[28], 1-2.78 m\(\cdot\)s\({}^{-2}\)[29; 30; 31; 32], 2-3 m\(\cdot\)s\({}^{-2}\)[28], >2.78 m\(\cdot\)s\({}^{-2}\)[29; 30; 31; 32], 3-4 and >4 m\(\cdot\)s\({}^{-2}\)[28]. Like the distance covered in different speed zones, there should be unanimity in the scientific community for the presentation of the results in the research studies that analyze the intensity zones of the external load variables collected by GPS devices and facilitate the understanding and comparison of the activity levels of athletes, as pointed out by [PERSON] et al. [48].