Cross country running has the highest rate of injuries of all high school sports.
The injury rate is even higher for girls than for boys.
The extremely high injury rate is caused by asking runners to train and race in the same week.
Most coaches know that you have to run very fast in practice to run very fast in races and the fastest way to train is to run intervals or fartlak, a series of short very fast bursts of running interspersed with slow jogging.
Training is done by running very fast on one day, have your muscles feel sore on the next day, and not running fast again until your muscles feel fresh.
The faster you run, the longer it takes to recover.
Most high school runners take at least a week to recover from the soreness caused by a race.
The coach typically takes them to a race on Saturday and asks them to run intervals on Monday or Tuesday, before they have recovered from the race.
They are either injured by that interval session or else they are injured by racing the next Saturday, before their leg muscle have recovered from the interval session.
If they run fast in races and slowly all the time in practice, they are less likely to be injured, but more likely to run slowly in races.
The most effective way to prevent injuries is for a coach to set up at least two teams.
Let each team race on alternate weeks, so each runner races on one week and trains fast twice in the next week.