This inquiry comes in from a concerned mom.
My daughter runs on a local cross country team. They start running every morning in the summer, 3 miles to 4 miles a day. In August they begin running 4-6 miles a day with races every weekend. In September they begin running 4-5 miles in the mornings and 3-5 miles in the afternoons. They had a retreat over the weekend and ran 20 miles of practice. Every year by this time of year…. the girls team of about 15 members, ages 13 years old to 18 years old at least 1-2 girls have stress fractures in their legs. Are they being trained too hard? Is this too intense for this age group?
The proof is in the pudding. Though teen runners are far more likely to encounter injuries due to their initial lack of conditioning and lack of year round training something like stress fractures at that rate is extreme. In all my years of coaching runners of all ages (including teen girls) I would be exaggerating if the incidence of stress fractures were as many as 1 in 300 (or more) per year. 1-2 out of 15 in a year is indeed beyond excessive.
The rule of thumb is still to increase mileage about 10% per week. So do the math. If they run everyday 3 or 4 miles per day they are running15-28 miles per week to start out. Then they are running as much as 8-10 miles per day – 50-70 miles per week! And compound that with a 20 mile run? For what purpose? Their cross-country race is only 5k!
No wonder these girls are hurting. Indeed there are differing philosophies – lots of miles versus the quality-over-quantity school. Even for the mileage folks that program is excessive for this age group. Many college level runners won’t run that kind of mileage. (One example; this past week I chatted with a sub-15:00 male college cross-country runner who ran less than 50 miles a week throughout his college career.)
Let’s compare that to quality-over-quantity research-based training. Moving from about 15 miles per week up to 30 miles per week (perhaps 35-40 for a very talented upper-classman) reduces injuries. The number one predictor of injuries is your history of injuries but a close number two predictor is total miles run; NOT the speed of those miles.
The proof is also in the pudding. I do not know what kind of times your girls are running but on 30 miles per week I have male runners who run 15-18 minutes and girls who can run 18-21 minutes. I think we have had one stress fracture in 3 or more years.
Train year round to get stronger to handle harder and longer workouts.
Keep quality training as part of your weekly workouts year round.
No drastic increases in mileage.
No excessively long long-runs.
Perform lower-leg running-specific strengthening drills.
Attend my high school running camp in the clean air of Flagstaff Arizona and learn research based ways to train while having a great time!