## 4 Discussion
However, the increase in these hormones, especially testosterone, is less abrupt and reaches lower concentrations in females than in males [15], which could explain why the changes observed in the parameters associated with muscle development between groups are only found in some of these variables. In fact, when age was introduced to the model, significant differences were found in most of the variables related to muscle development, which supports this hypothesis. Based on the results of the present research, the muscle development parameter could be used with some certainty in the detection of sports talent in the growth stage, as the influence of maturation seems to be limited, as opposed to what is observed with adiposity and bone development. However, since there are no previous studies that have analyzed the influence of maturation on bone and muscle variables in the female population, this is a question that should be further investigated in the future. Another objective of the present research was to analyze differences in the physical fitness tests of female volleyball players according to their maturity group. Significant differences were found between groups in the medicine ball throw and CMJ power tests. Although there are no previous studies that have analyzed this aspect in female athletes, the results of the present research are in line with those found in male adolescents, in which it was found that the early maturer group had better results than average maturres and late maturres in all tests that were dependent on muscle strength and power [3]. This could be due to the fact that previous studies showed that physical performance in the kinds of specific tests that require the use of muscle strength and power, such as the long jump, medicine ball throw, CMJ, sprint or agility tests, were favored by higher values of muscle mass and lower values of fat mass, together with other factors such as hormonal and neural factors [48; 49; 50]. In this sense, while in males, early maturres have greater muscle development than average maturres and late maturres [3; 51], in the present research carried out with females, it was found that the group of early maturres had greater muscle development but also greater adiposity than average maturres and late maturres. It is therefore possible that the potential advantage of greater muscle development in these tests may be minimized by the increase in fat mass and by the fact that the increase in muscle mass is more gradual than that among late maturres [45]. In spite of these promising results, many questions remain unanswered. In addition, no differences were found between maturation groups in the results of flexibility tests. While no previous research has looked at this issue in females, research in males found similar results [18; 52]. This could be because while some muscle groups tend to shorten due to histological and biomechanical factors over the years [53; 54], extensibility seems to be sensitive to changes produced by training, improving it and producing morphological and neurological adaptations [40]. Previous studies have already pointed out that women volleyball players have lower joint ranges as a result of adaptations produced by training [55]. Therefore, training effects could be the reason for the absence of statistical differences in flexibility between the maturation groups. One interesting finding is that when age was included as a covariate in the analysis of the differences between groups in the physical fitness tests, it was found that early maturres achieved greater distances in the medicine ball throw than late maturres and that there were differences in CMJ power between all groups, with better results in groups whose maturity was more advanced, with no differences in the rest of the physical tests.