Runners, in general, are pretty durable athletes. And when it comes to distance running, that resiliency tends to be even more crucial, especially throughout the long grind of a track or cross country season.
Typically, most athletes are racing multiple times per week, while also logging countless miles training when they're not competing.
As with most anything else, it takes an appropriate balance of activity to make it through the year unscathed.
But, regardless of one's skill or experience level, injuries happen, and are often unavoidable.