## 1 Introduction  
Visual impairment is a sensory disability that affects about 36 million people worldwide [1]. For equal participation in sport, people with visual impairment are categorizedunder three sections (B1, B2, B3). The B1 category includes people who have or do not have light perception and cannot recognize any items. Visual acuity is also stated with logMAR, which stands for the logarithm of the maximum angle of resolution (International Blind Sports Federation (IBSA), 2018), and it presents more than 2.6 points according to the IBSA classification system [2]. Previous studies have shown that visual impairment is associated with a low quality of life [3], as it causes a variety of difficulties in daily activities and limits interactions and independence. One significant problem that this particular population has faced is a sedentary lifestyle due to difficulties in transportation and mobility [4]. According to researchers [5], people with visual impairment who participated in sporting activities had a higher quality of life compared with those who had a sedentary lifestyle. Participation in sporting activities seems to reduce the sense of pain and, at the same time, improve mental health [3; 5]. Generally speaking, the improvement of physiological variables can help people with disabilities be healthier and more satisfied with their life [1]. Furthermore, the physical activity of people with visual impairment improves their social lives because, in most sports, and especially team ones, they socialize with other people [6]. As a result, this has a positive impact on their life satisfaction. There are many sports designed with rules adapted for this particular disability (visual impairment) (judo, wrestling, cycling and blind soccer five-a-side), but there are also sports that have their own unique set of rules, like goalball and beep baseball [6; 7]. There is a dearth of literature dedicated to people with visual impairment playing soccer. This can be concerning because of a variety of issues, for instance, the occurrence of injuries, the physical profile of soccer players, cardiorespiratory function, the effect of training on body composition, the internal and external workload that soccer players receive and the analysis of technical elements of the sport [6; 8; 9]. There are no specific data regarding all these issues, and generalizations are often made by other populations. Moreover, information on the maximum oxygen uptake of soccer players with visual impairment is very limited. Aerobic capacity can be improved with both continuing endurance training and high-intensity interval training [10]. Aerobic capacity is particularly important for the performance of soccer players. Previous studies have reported a correlation between the distance covered during the match and maximum oxygen uptake [11]. Nonetheless, in a recent study using global positioning system (GPS) technology, studies have shown that there is no correlation between the running distance covered by soccer players during the match and maximum oxygen uptake [12]. It has also been reported that an improvement of VO2 max by 6% may increase running performance during the match, the number of sprints and the number of actions with the ball [13]. In addition, high levels of aerobic capacity help soccer players cope with the demands and physical challenges of the match [14] and have faster recovery between intense actions during the match [15]. The studies that focus on the aerobic capacity of visually impaired people (soccer players and sedentary) are limited, and there are not enough data to compare these two populations. Also, a positive relationship (between VO2 max and match running performance) could affect soccer players' training and would help trainers estimate players' match running performance via laboratory measurements. However, no research to date has dealt with the relationship between the VO2 max index and covered distances of soccer players with visual impairment.