by Brian Boyle, PT, DPT
Stress Fractures Defined
Stress fractures are easily described as tiny cracks in bone which occur from overuse. Repetitive forces, such as those in long distance running, promote the regeneration of bone cells, however rest allows for the addition of new bone cells. If you are not getting enough recovery you will start to fatigue the bone putting you at a much higher risk for a stress fracture.
Where do Stress Fractures Occur?
The most common areas where stress fractures occur in runners are in the shin (tibia) of the lower leg and in the long bones (metatarsals) of the foot. But stress fractures can also occur in the hip and in the thigh (femur) of runners and while less common, are no less important.
If you suffer a stress fracture you may experience any of the following:
• Tenderness over a specific spot
• Increased pain and swelling with activity
• Earlier onset of pain with successive workout
• Continued pain even at rest as damage progresses (www.mayoclinic.com)
There are many other conditions and injuries, which are just as common in runners, which may present very similar to stress fractures and will vary depending on the location of pain. Some of the more common conditions that may present like a stress fracture include: tendonitis/tendinopathy, shin splints, and compartment syndrome.
While often times a stress fracture can be diagnosed from your medical history and physical exam alone, sometimes diagnostic testing is needed. It can often take several weeks, or more, for a stress fracture to show up on an X-ray, so the results will often come back negative if an X-ray is taken too early. Bone Scans, while a step up from X-rays, are not very specific for stress fractures and many bone problems will look alike on a scan. An MRI, while more costly, is currently the best choice to distinguish between stress fractures and soft tissue injuries and stress fractures will usually show up within the first week on an MRI.
Risk Factors and Training Errors: How Do we Prevent Stress Fractures?
Running experience plays a role and runners with no prior experience running are 2.5 to 3 times more likely to be injured. Weekly mileage and intensity of your runs can have an effect on injury rate as well. Rapidly increasing your distance (more than 5-10%) from week to week can significantly increase your chance of injury. And runners exceeding 40 miles per week are 3 times more likely to be injured than those staying below the 40 mile mark. It is also important to remember not to ignore early symptoms and seek medical assistance if you feel pain.
Dispelling Common Training Myths
• There is no documented data to show increased risk of injury, due to runners running on hard surfaces (concrete or road) versus running on softer surfaces (grass, dirt, treadmill).
• The incidence of stress fractures is unaffected by the use of “shock absorbing” insoles.
• There is currently no published data showing an increased risk of injury based on foot-strike pattern (pronation vs. supination) or barefoot running and injury.
• And shortening your stride length by increasing your running cadence, rather than lengthening your stride can help to reduce joint forces and the risk of injury
What Can I Expect If I Am Diagnosed With a Stress Fracture?
Typical recovery time from a stress fracture is between 6 and 8 weeks. During that time you will often be able to perform other activities, depending on where the stress fracture is, such as pool running, Anti-Gravity Treadmill running, and even cycling may be an option in order to keep your cardiovascular conditioning. You may also be required to wear a walking boot, use crutches, and in a worst case scenario surgery may be needed if a fracture is not healing. Your health care provider will give you more details about your particular injury and what you will need and or be able to do. You will also want to work out a return to running plan so that once you are cleared to return to running you do not return to previous training habits which caused the injury in the first place.
In summary, stress fractures can be prevented by following good training habits. Avoid increasing your training mileage by more than 10% weekly, allow for a rest day or days in your weekly training schedule to allow for adequate recovery, and recognize that as you increase your mileage you also increase the risk of injury. Shoe type, running surface, and shoe insoles so far have no documented effect on causing or reducing injury. If you do suspect you are suffering from a stress fracture consult with a healthcare provider immediately.
Buist et al (2008) Br J Sports Med
Gardner et al (1988) Am J Pub Health
Heiderscheit et al (2011) Med Sci Sports Exerc
Macera et al (1989) Arch Intern Med
Marti et al (1988) Am J Sports Med
Radin et al (1973) J Biomechanics
Walter et al (1989) Arch Intern Med
Brian Boyle, PT, DPT is a licensed Physical Therapist who works for Mountain Land Physical Therapy and Rehabilitation as the Clinic Director in the West Layton office. Brian is a former competitive runner and has over 15 years of experience in working with runners of all ages and ability levels. Mountain Land Physical Therapy has offices located throughout Utah and each office is equipped with high speed running video analysis equipment and trained staff ready to keep you at your best. For more information about the running video analysis or to seek treatment, go to www.mlrehab.com/run