Stress fractures don't happen because you ran. They happen because your recovery couldn't match your training.

When a runner gets a stress fracture, everyone audits the mileage. Too much, too soon, bad shoes. Almost nobody audits the other side of the ledger, which is whether the body ever had the materials and the stimulus to rebuild what the mileage broke down.

Bone is living tissue. Load it, feed it, rest it, and it gets denser. Load it while under-fueled and it quietly loses the race between damage and repair, one run at a time, until a metatarsal files a complaint. Heikura's work on elite distance athletes found the ones with low energy availability markers carried 4.5 times the career bone stress injury rate. Same sport, same mileage culture, wildly different fragility.

So my prevention program is not less running. It is lifting two to three times a week, deliberately loading bone and tendon: at least two anterior sessions, two posterior, plus core. Heavy enough to signal, consistent enough to matter. Bone adapts to what you ask of it, and running alone does not ask enough in enough directions.

The other half is the plate. Calories and calcium are the construction budget, and an under-fueled runner is running structural deficits no lifting program can cover. Five years injury free across 100 to 120 mile weeks is not luck. It is the ledger balancing.