Adolescent runners build bone that has to last a lifetime. Underfueling and menstrual disruption take the window away, and the first bone complaint goes to a physician.
Bone is still being built during the years many runners start training hard
Adolescence is not just a time to avoid injury. It is a time to build future resilience.
The body needs energy, calcium, vitamin D, and hormone support to use impact well.
A training jump without enough intake quietly changes the whole equation.
Not eating enough for the training is usually the real bone problem
Chronically low intake reduces hormone function and lowers the resources available for bone formation.
An athlete can be committed, high-mileage, and still be eating less than the training asks for.
If cycles are irregular or performance is sliding, that is a medical conversation, not a training tweak. Use the referral chain inside a school for who to tell, and in what order.
Calcium is a grocery number, and vitamin D is the physician's call
The Dietary Reference Intakes put ages 9-18 at 1,300 mg per day of calcium from food — the highest of any life stage, with a ceiling of 3,000 mg per day.
That is three or four servings, not a heroic effort: yogurt, plain, low fat (8 ounces) carries 415 mg, milk, nonfat (1 cup) carries 299 mg, mozzarella, part skim (1.5 ounces) carries 333 mg.
The same Dietary Reference Intakes put vitamin D at 600 IU per day for these ages, but very few foods carry much of it, which is why status is a blood question and calcium is a kitchen one.
A second bone stress injury is a referral, not a training-load puzzle
A second bone stress injury in the same athlete goes to a physician. It is not a load problem for a coach to solve alone.
Hip or groin, the front of the shin, the top of the foot, or the pelvis or low back: same-day evaluation, because those sites do not tolerate waiting.
Point tenderness on a bone, pain that lingers while walking, or night pain: stop running and get the athlete seen.