How does a stress fracture develop?

A stress fracture develops as a result of repetitive mechanical loading during activities such as running, jumping, or marching. When these activities are performed repeatedly, the bone is subjected to continuous stress that leads to the formation of microscopic cracks, known as microdamage.1

Under normal circumstances, the body repairs this microdamage and strengthens the bone through natural remodeling processes. However, if the volume or intensity of physical activity increases—such as when starting a new training program—the rate of microdamage accumulation can exceed the body’s ability to repair it. This leads to an accumulation of cracks and localized inflammation, which weakens the bone's structural integrity. If this process continues, the bone eventually reaches a point of fatigue failure, resulting in a stress fracture.1

The severity of the injury is determined by the specific location of the fracture and the extent to which it propagates across the bone.1