# Injury Incidence and Pattern in Elite Young Male and Female Trail Runners
## 4 Discussion
Additionally, more than half of acute sudden onset injuries are to the ankle, while the second most affected area, the knee, is usually by repetitive sudden onset or repetitive gradual onset. During the competition, the body is subjected to greater demands and fatigue, which increases the injury risk [52]. However, the prevalence of acute sudden onset injuries may also be due to the risks athletes take in intensity sports [53]. Trail running is a sport characterized by inconstant and unstable support. Although trail runners have greater stability in the joints of the lower body [54]. The leg joints, especially the ankle, require constant adaptation to the terrain, which can lead to injury in situations of intensity. Age may also be a factor, as young people are generally more prone to risk-taking than adults, who think more about the future consequences [55]. Likewise, this youth could explain why 57.0% of the injuries are new, compared to 29.5% of recurrent and 12.5% of exacerbation injuries, since practicing the sport at a high level for less time may reduce the time of exposure to possible injuries. In another study on trail running [26], despite agreeing that the ankle is the most affected area, they differ in their origins, indicating that most are repetitive gradual onset. The results of our study indicated that joint sprain was the most common injury with 43.2% of the total produced, followed by tendinopathy (18.9%). Furthermore, 95.1% of joint sprains were in the ankles, while tendinopathy was mainly distributed between the knee and the ankle. The ankle is the first of the joint chain that must adapt to the different variations in the terrain and its properties to generate movement, so therefore, the one that receives the first impact [56]. For other modalities of running with steady surfaces, most are stress injuries, highlighting tendinopathy in different parts, as well as periostitis in the tibialis [36]. In mountaineering, most of the ankle injuries are bone fractures (65%) followed by joint sprains (35%) [47]. The reasons might be due to specific characteristics of mountaineering that are not found in trail running. First, the added weight of the backpack increases the load to be borne by the joints. Second, the ankle is usually protected by a rigid boot, which largely prevents joint sprains. Consequently, injuries are usually due to a fall at a certain height or some other cause that the boot is not able to prevent, which in turn might be increased by the backpack weight. Orienteering, a sport similar to trail running, reports percentages of ankle injuries comparable to our study [47]. The differences in incidence by sex indicated that the percentage of injury in female runners is lower than in male runners: 1.8 \(\pm\) 1.3 and 2.3 \(\pm\) 1.9 injuries every 1000 h, respectively, as also observed in male vs. female runners of other modalities [12; 57; 58]. These studies conclude that males have a significantly higher risk of running-related injuries than females, particularly young male athletes (<40 years). While navicular drop remained as the only significant injury predictor in female athletes, body mass index, confidence interval, or previous occurrences were associated with running-related injuries in male athletes [58]. The most affected body region for both sexes was the ankle, but while male runners reported 54.3% of the affected areas, female runners reduced this affection to 36.0%. Although there were no differences at the moment at which they occurred, there were differences in the type of injuries sustained. While in male runners 55.7% were acute sudden onset, followed by repetitive sudden onset (30.0%), the main cause in female runners was repetitive sudden onset, with 48.0%, followed by acute sudden onset (32.0%). It is also noteworthy that joint sprains predominated in male runners, while they are more evenly distributed in female runners.