###### Abstract  
The aim of this systematic review was twofold: to identify the main trends and issues that are being addressed by researchers in the context of physical fitness and sports performance in deaf and hard-of-hearing (D/HH) athletes and to indicate the needs and future directions that should be implemented in the training process of athletes with hearing impairments. The methodology of this systematic review was planned according to PRISMA guidelines. A search of electronic databases (PubMed, EBSCO, Scopus) was conducted to identify all studies on physical fitness, sports performance and participation, and D/HH athletes from 2003 to 2024. In total, 87 full-text articles were assessed to determine eligibility, while 34 studies met the inclusion criteria and were subjected to detailed analysis and assessment of their methodological quality. The presented systematic review indicates evidence that D/HH athletes are characterized by a similar or higher level in selected motor abilities compared to hearing athletes. Moreover, it seems that hearing impairment is not a barrier in the development of an athlete's physical fitness, including aerobic capacity, muscular strength and power or speed of reaction. Furthermore, inclusion in sports participation and specific tools (i.e., communication aids) appear to be crucial factors for performance enhancement. VO2 max; sports training: muscular strength; aerobic capacity; postural control; inclusion; physical fitness; Deaflympics; physiological profile +
Footnote †: journal: Medical  
As disability is a multidimensional concept [8], three main athletic movements can be indicated: (1) the Paralympic Games; (2) Deaflympics; and (3) the Special Olympics. Each of them is characterized by a long tradition; however, only deaf sports are confined to a small sample of the population of people with impairments [9]. Therefore, the uniqueness of sports for people with deafness gives them multiple opportunities, especially in the context of socializing with those who have similar social needs; nevertheless, at the same time, there are multiple challenges that should be taken into consideration, including communication [10]. Moreover, deaf and hard-of-hearing athletes seem to experience a different level of sports participation [11], which can be related mostly to the intrinsic differences in their morpho-functional development [12], which requires coaches to have special skills and the ability to adequately adapt methods and forms of training to the individual needs of the deaf athlete. One of the most challenging issues in the context of deaf sports is to deal with the effects of the intrinsic disturbances of the somatosensory and vestibular systems on athletic performance [13]. As was indicated by [PERSON] et al. [14], the hearing and balance organs of the human body are closely related; thus, an impairment of the abovementioned systems impacts the muscular coordination mainly by reducing motor function and decreasing balance. However, in the context of the Deaflympics, among the athletes that are eligible to compete in this event, there are no restrictions except for the loss of at least 55 dB in the better ear [15]. Compared to the Paralympic Games, there are not as many adaptations required for a single sports discipline as there are for multiple physical, visual or intellectual impairments [16]. This may affect the development of a unique sporting environment, in which only D/HH athletes can integrate and interact with the population of people with hearing impairments. It should also be admitted that deaf sports should be seen as a phenomenon that impacts both the social and physical aspects of people with deafness and the hard of hearing. To date, several qualitative analyses concerning the population of people with deafness or hardness of hearing have been undertaken [17; 18; 19]; however, it is difficult to find a systematic analysis that has analyzed the issue of deaf sports.