## 1 Introduction
Such differences in the motor development of blind children undoubtedly affect the morphofunctional state of the blind adult, including his or her body posture, movement skills, and motor abilities. This may be particularly evident when the blind are subjected to specialized sports training, which always affects biomechanical adaptation in body posture, as has been shown among both able-bodied and disabled athletes. Physical activity, including sport for the visually impaired, is an antidote to the sedentary lifestyle imposed by disability and the lack of naturally acquired skills to support their development. Scientific studies have shown a low level of physical activity among people with visual impairments, which is related to internal barriers (fear and reluctance to exercise) and external barriers, including architectural and urban barriers. As already mentioned, a specific group consists of people with visual impairments who practice sports. A particular challenge for this disability group is practicing team sports, where the essence is competing against an opponent and working together as a team while overcoming individual limitations. For many years, the only game for the blind and visually impaired was goalball. It is a Paralympic sport in which players compete in teams of six (three on field, three substitutes) and their goal is to hit a 1.25 kg rubber ball with metal bells embedded inside it into the opponent's goal [17,18]. During the attack, players usually take a few steps of run-up or turn, followed by a throw. In defense, players assume a low position, moving to a fall on the side with arms stretched above the head and legs straight. The variability of body position during the game and its dynamics are a challenge for players and can cause injuries that generate musculoskeletal pain. Authors argue that goalball is a high-injury risk sport [19,20]. [PERSON] et al. [21] showed that during the London Paralympic Games (2012), goalball was the sport with the third highest injury rate (injury rating level 19.5), thus generating musculoskeletal pain. While there have been studies on visually impaired athletes, there are no studies that have considered the influence of both disability and sports training as variables influencing body posture and musculoskeletal pain. Given the gap in research assessing both the variability in posture due to blindness (intrinsic compensatory mechanism) and goalball practice (adaptation to the sport and induction of an extrinsic compensatory mechanism), the study aimed to examine the relationship between musculoskeletal pain in elite Polish goalball players and selected physique and postural characteristics. Therefore, the operational objectives of our study of elite Polish goalball players were: (1) determination of the incidence and locations of musculoskeletal pain; (2) assessment of body structure and composition; and (3) identification of the presence of biomechanical changes in posture (amount of anteroposterior curvature of the spine, pelvic alignment). It was assumed that adaptation to sport is a factor that generates biomechanical compensations in posture and body physique, which may vary due to visual impairment and affect habitual posture and, consequently, the occurrence of musculoskeletal pain.