1.What exactly is a stress fracture?
A stress fracture occurs where there is an inability of the bones’ intrinsic repair process to keep up with the stresses applied to it over time. Ultimately, this leads to a break or fracture in the bone. In short, it results from an abnormally high stress placed on normal bone leading to fracture.
2.What are the causes/predisposing factors of this injury?
One of the most common causes is overtraining. Either too much volume or too much intensity, or both together, without the appropriate lead up can be so overwhelming that the increased workload causes bone failure over time.
Structural misalignments—such as overpronation from a flat foot or excessive supination from a high arched foot—can also lead to stress fractures since they can place high loads on bone. Footwear that is inappropriate or worn out can also cause higher than normal stresses on bones and cause stress fractures.
In women, diminished bone density can also predispose to stress fractures.
Poor diets that are low in calcium and other minerals required for bone health can also contribute to stress fractures.
3.What are the symptoms?
Stress fractures usually present as point tenderness over the fracture site. The pain may be felt at rest and intensifies with activity, especially weight bearing activity. Most stress fractures occur in the lower part of the body especially the tibia and foot, but can also occur in the fibula, pelvis and neck of the femur.
4.What can be done to prevent or treat this injury?
Proper training and preparation for activity is essential. Build up mileage by no more than 10 percent to 15 percent per week and do not do back-to-back hard days. Try not to run on overly hard surfaces all the time, vary runs on trails or grass or treadmill if possible.
Speedwork and high intensity training should be preceded by a warm up and a stretch, and followed by a cool-down.
Any biomechanical issues should be addressed with proper shoes and orthotics, if needed. Old shoes should be discarded, and optimally, two pairs of shoes should be rotated on alternate runs.
A diet with appropriate caloric and nutrient content is also important, especially calcium and vitamin D, which are critical for bone health.
Treatment consists of relative rest (non-weight-bearing activity) for up to eight weeks (more with femoral fractures). Activity during this time should be non-impact such as pool running or biking. A gradual return to weight-bearing activity can begin after two to three weeks of being pain free. Some studies suggest using an air splint (cast), but results are equivocal. Anti-inflammatories and icing may also be used to reduce pain and inflammation.
I also find that treating the muscles and soft tissues around the fracture site, to restore proper tone, strength and balance to be essential for a full recovery.