## 4 Discussion
### Severity of Traumatic and Overuse Injuries and Affected Body Parts  
Most traumatic injuries were moderate (41.3%), which means a time-loss of training of 8-28 days, whereas only 15.4% were severe (time-loss of >28 days). These findings are in line with previous  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Variable** & \
\begin{tabular}{c} **\% Observations** \\ **with Injuries** \\ \end{tabular} &
\begin{tabular}{c} **N Observations** \\ **with Injuries** \\ \end{tabular} & **N Observations** & \(p\) & **OR**1  & **OR**1  & **95\%CI ub**3  \\ \hline Height percentile group \({}^{7}\) & & & & & & \\
25 and & 6.9\% & 8 & 116 & 0.110 & 0.43 & 0.15 & 1.21 \\
25 to \(<\)75 & 6.4\% & 19 & 295 & 0.088 & 0.44 & 0.17 & 1.13 \\
75 and & 14.1\% & 9 & 64 & 1 (ref) & & & \\ above & & & & & & & \\ \hline Weight percentile group \({}^{8}\) & & & & & & & \\
25 and & 4.2\% & 5 & 118 & 0.140 & 0.39 & 0.11 & 1.36 \\
25 to \(<\)75 & 8.0\% & 23 & 286 & 0.616 & 0.77 & 0.27 & 2.16 \\
75 and & 11.4\% & 8 & 70 & 1 (ref) & & & \\ above & & & & & & & \\ \hline \hline \end{tabular}  
* \({}^{1}\) OR: edits ratio, \({}^{2}\) 95%CI lb: 95% confidence interval lower bound, \({}^{3}\) 95%CI ub: 95% confidence interval upper bound, \({}^{4}\) groups according to age at peak height velocity, \({}^{5}\) according to distance to age at peak height velocity, \({}^{6}\) missing observations = 36, \({}^{7}\) missing observations = 7, \({}^{8}\) missing observations = 8.  
\end{table}
Table 4: _Cont._studies in youth ski racing (44.9% moderate; 13.1% severe) and adolescent ski racing (15-19 years; 46% moderate; 41% severe) [5], whereas at the World Cup level, most injuries were classified as severe injuries (>36%) [30]. However, at the World Cup level, injury registration was performed retrospectively, which might lead to the assumption that not all minimal and moderate injuries were reported, as it was done in the present prospective study. With respect to injury location, the present results confirm previous findings in youth ski racing [6], adolescent ski racing [5], and elite ski racing [3]: most traumatic injuries (66.3%) affected the lower extremities; most of them were located at the knee. Based on these findings, it can be concluded that also in youth ski racing, the knee is the most vulnerable body part by traumatic injuries.  
Most overuse injuries were mild (33.3%), followed by moderate (30.6%), minimal (22.2%), and only 13.9% were categorized as severe. Only 15% of the overuse problems were recurring, which is a finding that is comparable with a previous study in youth ski racing, in which 23.1% of the reported overuse injuries were recurrent [4]. This finding indicates that the youth athletes had sufficient time to recover, and the pressure to return to training and competition or train despite symptoms was not that high. In line with a previous study in youth ski racing [4], the lower extremities were the most affected body parts also by overuse injuries; in the present study, 82.4% affected the lower extremities, which is comparable to the 82.3% affecting the knee in the reported study [4]. Growing athletes suffer from unspecified but self-limiting knee problems; the growth rate of the apophysis is slower than that of the epiphyseal plate, leading to problems of the interface between bone and ligaments; most overuse injuries were classified as typical apopphysitis, such as Osgood-Schlatter disease [31]. Based on the present and previous findings, it can be concluded that in young ski racers, overuse problems are more relevant in the lower extremities, whereas the older the athletes are, the more overuse problems in the trunk become more relevant [5].