## 4 Discussion  
The aim of this study was to analyze the joint characteristics of the foot and ankle in junior and young adult competitive swimmers and their relationship with muscular pain during training. Research on injuries in swimming has mainly focused on the upper limb [20], although from previous studies, it is known that leg kicking improves propulsion and speed by 31% [21], demonstrating that leg movement and muscle work is three to five times greater than arm movement [15]. To our knowledge, this is the first study to report joint characteristics of the feet and ankles of elite swimmers. On the prevalence of muscle pain, several researchers sustain that women tend to injure themselves more often [2; 4], possibly due to their shorter limb length, which implies a greater cadence [22]. On the other hand, [PERSON] et al. [23] suggest that men are more likely to be injured. We agree with [PERSON] et al. [24] and [PERSON] [25], as no significant differences were observed between men and women. Several studies have indicated that men exhibit a higher incidence of injuries compared to women in various sports, including swimming, due to differences in biomechanics, body composition, and levels of strength and flexibility [1]. Specifically, research has reported that male swimmers may be exposed to greater muscular loads in the lower limbs, which could influence the prevalence of  
Figure 1: Graph showing the group comparison resulting from the two-stage cluster analysis. muscle discomfort and injuries in this population [26]. The hannstrings are a frequent area of injury in athletes [27]. Lack of flexibility of the gastrocnemius muscles has an impact on pathologies related to the ankle and foot [28], hallux rigidus, plantar arch stiffness, and plantar fascitis. Tightness in the posterior musculature limits the dorsal flexion of the ankle and has an impact on the appearance of muscular pain, maybe due to the maintained position in plantar flexion that swimmers adopt. [PERSON] et al. [27] state that maintaining a greater degree of plantar flexion and ankle inversion increases speed by 29.3% and makes the swimmer more effective. There are several studies that express the importance of maintaining ankle and foot posture in PF on swimming speed [29]. [PERSON] [30] states that more experienced swimmers work with a smaller joint angle than more novice swimmers. The present study confirmed this finding, as the adult swimmers had a smaller joint angle than the junior swimmers. Both junior and adult swimmers showed a decrease in ankle dorsal flexion below values considered normal (15-20 degrees with the knee extended) [31]. In this study, participant classification was based on age category, as the main objective was to evaluate the differences between junior and adult swimmers in relation to plantar characteristics and the presence of muscle discomfort. Previous studies have indicated that, in competitive swimmers, biomechanical differences between men and women may be less pronounced due to sports adaptation and the similarity in training loads [4; 21]. Regarding the distribution of muscle pain, our results showed no significant differences between sexes (\(p\) = 0.587), suggesting that gender was not a determining factor in this variable within our sample. This finding aligns with previous studies that have analyzed the prevalence of injuries in high-performance swimmers and have not found clear differences between men and women [17; 18]. With regard to the characteristics of the first ray in swimmers, as well as the dorsal flexion of the first MPJ, previous research has shown that the etiology of the plantarflexed first ray may be due to muscular misbalance [32]. The results of this work show an increase in plantar flexion of the first ray. This could be due to a shortening of the posterior musculature and possibly of the plantar musculature because of the maintained plantarflexed position of the foot and ankle during the sports activity.