Bone Stress Injuries in Long Distance Runners
Bone stress injuries (BSIs) are common, particularly among long-distance and high-volume runners. These injuries should always be considered as a potential source of pain, as they can significantly affect a runner’s ability to train and perform.
Running is a highly popular form of exercise with numerous health benefits, such as improved cardiovascular and mental health. However, like all forms of physical activity, running comes with its own set of risks. Bone stress injuries, in particular, are prevalent among runners who engage in high-volume or long-distance training. They are often linked to factors such as an increase in training volume, insufficient rest, training errors, biomechanical issues, or nutritional deficiencies. Understanding the development of BSIs and how to prevent them is essential for any runner aiming to maintain optimal long-term health and performance.
What is a Bone Stress Injury (BSI)?
Our bones are constantly undergoing a process of remodeling in which old bone tissue is replaced by new bone tissue. This process is essential for maintaining bone strength, repairing micro-damages, and regulating calcium levels in the body. When training volume increases too quickly or becomes too intense, micro-cracks begin to form in the bone, weakening its structure. Over time, the bone’s ability to repair itself becomes overwhelmed. The bone then becomes more porous, and with continued stress, a BSI can occur.
Typically, BSIs develop over a period of about 4-10 weeks. This means that the increase in training intensity or volume likely occurred at least a month prior to the onset of symptoms. BSIs are classified on a spectrum, ranging from Grade 1 to Grade 4b. Grade 4b represents a complete fracture, while Grades 1 to 3 indicate varying degrees of inflammation and damage. Grades 1-3 are often not visible on standard X-rays, making MRI the gold standard for diagnosing BSIs. Early detection is crucial, as untreated BSIs can progress to Grade 4 fractures.
Why Are BSIs So Common in Runners?
Despite its numerous benefits, long-distance running is not inherently a bone-building activity. Bone cells require continuous stimulation and adaptation to rebuild and remodel properly. However, after approximately 100 repetitive loading cycles, bone cells tend to “plateau” and stop adapting. For context, an average running cadence is around 160-180 steps per minute, which doesn’t provide enough variety in stimulus for optimal bone health.
To prevent BSIs, it’s essential for runners to incorporate different types of bone-loading activities, such as weight training and plyometrics. These exercises create a varied stimulus that alters the muscle pull on the bone, which is necessary for continued bone adaptation and strength. With the right knowledge and approach, bone health can be optimized, reducing the risk of BSIs.
Common Sites for Bone Stress Injuries
BSIs are most commonly seen in the following areas:
- Tibia
- 5th Metatarsal
- 2nd Metatarsal
- Navicular
- Fibula
- Femoral Neck
- Pubic Bone
Signs and Symptoms of a BSI
The typical symptoms of a bone stress injury include:
- Pain at rest or discomfort during activities that were previously pain-free
- Pain that does not “warm up” or worsens with exercise
- Localized, pinpoint pain at the site of the injury
If you experience any of these symptoms, it’s important to seek professional evaluation as early diagnosis is key to avoiding further complications.
Treatment of Bone Stress Injuries
The treatment for BSIs is multifactorial and should be tailored to the individual based on the severity and location of the injury. A thorough assessment and diagnosis are essential for developing an effective rehabilitation plan.
Rehabilitation typically begins with rest or offloading the affected bone. The length of this rest period depends on the grade of the BSI. Once the bone has had sufficient time to heal, rehabilitation will progress to strength training. Muscle strength plays a critical role in supporting bone health and preventing future injuries, so gradually increasing strength is an important component of recovery.
In the final stages of rehabilitation, plyometric exercises may be introduced to further stimulate bone remodeling, and a gradual return-to-running program will be implemented.
Nutrition is another crucial aspect of recovery. High-volume runners are at risk of low energy availability due to the intense demands of their sport, which can impact bone health. Proper fueling—ensuring adequate caloric intake, as well as sufficient calcium and vitamin D—is essential for healing and injury prevention. If recommended, a referral to a nutritionist or sports dietitian can help assess and optimize your diet to support recovery and performance.
Biomechanics also play a role in preventing and managing BSIs. A thorough biomechanical assessment via treadmill analysis can help identify any sub-optimal movement patterns or weaknesses that may contribute to abnormal stress on the bones. Addressing these issues with exercises or modifications to running form can reduce the risk of further injuries.
Prevention
The key to preventing BSIs is a holistic approach that includes proper training progression, strength training, a well-balanced diet, and attention to biomechanics. By balancing load and recovery, incorporating bone-strengthening exercises, and addressing any weaknesses or imbalances, runners can significantly reduce the risk of bone stress injuries.
If you suspect you may have a bone stress injury or want to learn more about injury prevention, schedule an assessment with Tanya Chumak. A full evaluation can help you develop a personalized plan to stay healthy, strong, and injury-free in your running journey.
