Injury Focus Series 002

Stress Fracture

Of all the running-related injuries, there is one injury swifter and more decisive than all of the others: the dreaded stress fracture. Seemingly appearing out of nowhere, a stress fracture nearly guarantees at least 6 weeks completely free from ground running. 70% of all running-related injuries are various stress fractures. However, there is good news as there are many lifestyle steps that all runners can take to reduce risk, and with patient recovery, your bones are able to build themselves stronger to prevent injury and rebuild themselves stronger after injury.

What is a stress fracture?

A stress fracture - to put it simply - is a small crack in a bone of your body. It is preceded by a stress reaction, which is a severe bruising of the bone, and if a stress fracture gets bad enough - it could result in a full fracture. Amongst runners, stress fractures most commonly occur in the tibia, followed by the second and third metatarsals, which are thinner than the first metatarsal (connected to the big toe) and because this area takes a tremendous amount of impact on your foot as you push off from the ground. They also commonly occur in the heel, ankle, and midfoot. Besides feet, stress fractures can occur in the lower back, femur, hips, and sacrum. It is very uncommon to see stress fractures in the arms, upper back, and neck, as these areas do not bear load during running.

Signs indicating the possibility of a stress fracture include pain that worsens as a run progresses, a sharp pain that you can pinpoint, pain even when resting, changes to your running form, and swelling to the affected area. If a stress fracture is suspected, try carefully hopping on the injured leg. If it hurts to land, you could have a stress fracture. As always - please make sure to consult a health professional if you are worried about your injury status.

How do stress fractures occur?

Overuse is the main cause of running-related stress fractures. The repetitive impact of running causes microscopic damage to bone, and a stress injury begins when a fatigued muscle isn’t able to respond to shock and tension as it should. The muscles begin transferring all of these forces to your bones, and overtime the bone begins to swell inside (stress reaction). Unattended to, the swelling of a stress reaction develops into a crack - the dreaded stress fracture.

There are several risk factors that can make you more at risk for developing a stress fracture. The first is low bone density. Osteoporosis, irregular periods and low BMI in women, nutritional irregularities (restricting caloric intake, low calcium, high caffeine and sodium intake), and even winter (which can cause low vitamin D) increases risk for development of stress fractures. Second, would be to abruptly increase the volume or intensity of training; it is helpful to limit increases in mileage and intensity by <10% week to week. Third, changes in surface such as those from trails to road or road to treadmill, can also be a cause for stress fractures. Some winter days force even the most rugged of runners indoors, so it is helpful to be careful and mitigate your injury risk when you are changing surfaces. Lastly, be mindful to change your running shoes every 350-450 miles, because worn-out shoes lose their shock-absorbing ability transferring that impact to your bones.

What does stress fracture recovery look like?

The number one thing to do is to STOP running! Consult your trainer, coach, or doctor to get a diagnosis, a recovery timeline, and a return-to-running plan. While you can employ RICE to manage pain and swelling at first, the most important aspect of recovery is to abstain from bearing weight for anywhere from 4-12 weeks (professional prescribed) while the bone is healing. Your health professional will most likely place you in a walking “air-cast,” or depending upon the location of the fracture, crutches for the majority of your rehabilitation period.

Non weight-bearing activities such as swimming, pool running and stationary biking are encouraged to maintain fitness while you wait out the slow, yet all-but-guaranteed, healing process. During this time, it’s a good idea to reflect on what might have caused the injury, and set out a plan to improve any potential causes, whether they be related to abrupt training changes, nutrition, shoes, muscle weakness, foot stability, or running form.

When you are cleared to run - you should slowly transition back to ground running as your bones strengthen. Your bones are living things that are constantly remodeling themselves and since they have been unloaded and unstressed for the last 4-12 weeks it is important to make this transition slowly. If you aren’t giving your bones enough time to rebuild themselves while you build back up, you’re running a risk of redeveloping a stress reaction or fracture.

How can BWS and LEVER help my bones?

The progression from non weight-bearing activities to full-on running used to require the types of resources that only physical therapy clinics and high-level collegiate programs (hello, Alter G’s and underwater treadmills!) have in their repertoire. However - this is no longer the case! LEVER has brought body weight support to the home and commercial treadmill in an affordable package. LEVER is a great BWS tool that can help you safely transition from non-weight bearing exercise to ground running. We are able to help you safely reduce up to 45 lbs (20 kgs) of your own weight while running. Many runners know the sheer joy when they can finally progress to any type of activity that resembles normal running, now imagine you can take that freedom with you in a nifty bag as long as you can find a treadmill! Here at LEVER, we want to help YOU return to running from a bone stress injury as safely, pain-free, and as flexibly as possible.

In a scenario where you’re not coming back from an injury and the skies have dumped a foot of snow overnight (as so often happens here in Boulder in the winter) - the chances of getting your long run done outside has dropped to zero. Studies show that abruptly completing a high volume of training on a treadmill can lead to stress fractures, so you can help counteract the risk associated with this abrupt change in running surface by using LEVER to offload 10-15% of your body weight to ensure you aren’t overloading of your bones while still getting the volume and intensity in that you need!

In this blog, we’ve explained what stress fractures are, how they occur, and how LEVER can be a resource to the athlete rehabbing a stress fracture or the athlete trying to avoid injury. We hope you find this resource useful!

Nell Crosby, M.S.

Romani, William A., Joe H. Gieck, David H. Perrin, Ethan N. Saliba, and David M. Kahler. “Mechanisms and Management of Stress Fractures in Physically Active Persons.” Journal of Athletic Training 37, no. 3 (2002): 306–14.