## 4 Discussion  
Although the physiology and aetiology of injuries in the world of women's football have been studied extensively, genetics remains a field that deserves more interest, and the author is presenting, for the first time, a study on the association between muscle injury-related genes and the epidemiology of injuries in women's amateur football players during a whole season. The aim of this study was to examine the association between muscle injury-related genes, injury risk and injury aetiology in women's amateur football players. The main finding is the correlation between genotype frequencies and different injury characteristics, with the C allele of the _AMPD1_ c.34C>T polymorphism, suggesting some kind of benefit related to injury prevention, especially for protection against tendon/ligament injuries and severity, as well as with the C allele of the _ACTN3_ c.1729C>T polymorphism. The morphological characteristics of women football players may increase the risk of injuries such as stress fractures, and affect their overall strength and power on the pitch, as well as expose them to higher risks to certain types of injuries, as shown in previous studies on the Spanish League [15; 33]. In recent years, the demands of training and matches have increased considerably in women's football, even for amateurs [34]. The overall epidemiology of injuries is similar to that of men's football, although the proportion of severe injuries is higher in women football players [2; 35], totalling 17.2% in this study, showing a higher frequency of injuries than previously reported in men football players [36], which could be associated with significant costs [37]. The risk of severe knee injuries and ankle grains is at least twice as high in women as in men football players, regardless of exposure or level of participation [38; 39], which is consistent with the data presented in this study. Genetics may influence the risk of muscle injury in women football players, with a focus on tendon and ligament injuries. A recent study found that variations in the _COLSA1_ rs13946 polymorphism were associated with increased risks of ACL tears and muscle injuries in women's football players. These variations were associated with differences in ligament laxity between genders, making women football players more susceptible to these injuries [22]. In this regard, the _AMPD1_ c.34C>T polymorphism in this cohort of women's amateur football players showed different injury aetiology characteristics from previous studies in men's professional football players [18]. The CC genotype was more frequent in non-injured players (53.2%) compared to players with the TT genotype (14.3%), an aspect that could present the CC genotype as a protector genotype in tendon and ligament injuries. This is the first time that these results have been presented for women's football, also showing an association with the severity of injuries in the TT genotype (75.9%), as has been presented in men's professional football players [18]. Other studies have found that variations in the _ACTN3_ gene are associated with an increased risk of muscle injury. Specifically, individuals with the TT genotype in the _ACTN3_ c.1729C>T polymorphism could have an increased risk of muscle strains and tears, which are common injuries in women football players [25; 40]. The results presented in this study show a lower severity of injuries in the CC genotype compared to the TT genotype, similar to the data found previously in men's professional football players [18]. There was an association between match and training injuries in muscle damage genes, such as the _CKM_ c.*800A>G polymorphism, in which, when comparing training and match injuries, it was shown that the GG genotype and G allele lead to higher risks of training injuries in women's amateur football players. These data differ from those found in a recent study in which no association was found between this polymorphism and the risk of training and match injuries in men's professional football players [19].