Stress fractures are tiny cracks in a bone. They're caused by repetitive force, often from overuse — such as repeatedly jumping up and down or running long distances. Stress fractures can also arise from normal use of a bone that's weakened by a condition such as osteoporosis.
Stress fractures are most common in the weight-bearing bones of the lower leg and foot.
Symptoms
At first, you might barely notice the pain associated with a stress fracture, but it tends to worsen with time. The tenderness usually originates from a specific spot and decreases during rest. You might have swelling around the painful area.
Causes
Stress fractures often result from increasing the amount or intensity of an activity too quickly.
Bone adapts gradually to increased loads through remodeling, a normal process that speeds up when the load on the bone increases. During remodeling, bone tissue is destroyed (resorption), then rebuilt.
Bones subjected to unaccustomed force without enough time for recovery resorb cells faster than your body can replace them, which makes you more susceptible to stress fractures.
Risk factors
Eating disorders and lack of vitamin D and calcium can make bones more likely to develop stress fractures.