Why Stress Fractures Happen and How to Treat Them

By: Dale J. Buchberger, PT, DC, CSCS, DACBSP

Stress fractures are among the most common overuse injuries sustained by long-distance runners, and they affect everyone from recreational runners to world-class athletes, male and female. People with stress fractures typically complain of pain in a specific area or region of the body. Symptoms gradually worsen and most commonly occur from the pelvis to the lower extremity. Patients provide a history of pain that is aggravated by physical activity such as training for endurance events and relieved by rest. Patients usually recall a history of a recent and dramatic increase in exercise volume, the initiation of a new activity, or some other change in their routine.

Overuse injuries strike endurance athletes such as marathon runners because of the demands of the sport and the makeup of the athletes. Distance running requires athletes to perform the same movements repeatedly; subjecting the same muscles to overuse and subjecting the same joints and bones to sustained impact. Making matters worse, runners often condition their minds to ignore pain, driving them to push muscles, joints and bones to the brink of injury. When a runner’s muscles fatigue, it forces them to compensate by bouncing higher in the air during their stride; this forces the legs and pelvis to absorb more impact. A runner might also be forced to compensate during their stride for imbalances in posture or leg length, again forcing the legs and pelvis to absorb greater impact.

One of the top training errors that can lead to stress related fractures is a rapid increase in training intensity which can occur in two forms: a large increase in mileage and/or an increase in training speed (running faster more often). For years the 10 percent rule has been used to govern changes in weekly mileage. Unfortunately the fault in the 10 percent rule is that it is weekly and does not account to increases in training pace or the addition of speed work. Many people do not accommodate on a weekly basis and actually take 2-3 weeks to accommodate. This is why many runners that use the 10 percent rule still get hurt or experience stress fractures.

Running on hard surfaces such as roads and sidewalks, especially on cambered road surfaces that slant to the side to allow water drainage, puts a long distance or marathon runner at greater risk for a lower extremity or pelvic stress fracture. While the rigors of training already strain a runner’s pelvis and lower extremities, the strain can become even more significant when a runner suffers from a dietary deficiency and/or an eating disorder. Depleting the body of necessary nutrients and specific muscular weaknesses in the hips prevents adequate recovery from strenuous training routines.

If you are a distance or marathon runner, the simple rule of thumb regarding stress fractures of the pelvis and lower extremity is as follows: Stress fractures below the knee (leg, ankle, foot) are generally considered training related injuries from impact stress. These injuries occur from a combination of rapid increases in training volume and intensity, worn footwear, hard surfaces, etc. Stress fractures occurring above the knee are first and foremost “dietary stress fractures”. This does not mean that training errors may have contributed to the fracture it means that the diet is grossly deficient in two main areas; calcium and total usable calories.

Many runners often confuse the beginning stages of a stress fracture with a simple muscle pull. However, unlike the pain of a muscle pull, the pain of a stress fracture will not subside during a run nor will it loosen up with stretching. When a runner sustains a stress fracture, initially they might feel a deep, aching pain that remains localized in the region in question. However, as the injury remains untreated, the pain can spread to other areas of the body as the brain compensates for the injury.

Stress fractures are usually diagnosed by using an MRI or CT scan. It has been reported in medical journals that stress fractures are missed on plain x-ray 85% of the time. If a lower leg, ankle or foot stress fracture is diagnosed, the treatment is to rest, find alternative non-weight-bearing activities, correct running shoes, begin a structured rehabilitation program, and review training logs for signs of training error. If a stress fracture above the knee (pelvis, sacrum or femur) is diagnosed, running activities must be discontinued and the diet scrutinized for total available calories and calcium intake. If the diet is not checked, the patient may suffer a repeat stress fracture within a few months when the patient begins training again.

Stress fractures in high level and recreational distance runners are a very common injury. These injuries are treated by training and dietary correction. If your condition does not resolve in 14 days it most likely needs medical assessment and care.