How can I reduce my risk of stress fracture?

No injury strikes fear into the heart of a runner more than a stress fracture. Stress fractures are painful, require significant rehab, have high healthcare costs and can take you away from doing what you love for months. So, what can you do to avoid this dreaded injury?

What is a stress fracture?

Stress fractures are tiny cracks in bone, caused by repetitive stress, or force from overuse. A stress reaction is similar to a deep bone bruise and is a precursor to stress fracture.

What are the risk factors for stress fracture?

Risk factors for stress fracture in runners are generally either training or nutrition-related. Some of these cannot be controlled but many can!

Known stress fracture risk factors:
-History of previous stress fracture
-Large/rapid increase in training volume
-Lower bone density
-Muscle weakness
-Leg length differences
-Menstrual disturbances
-Low energy (calorie/kilojoule) intake

What is the best nutrition to reduce the risk of stress fracture?

Whilst we may think of bone as little more than structural support, it is important to understand it is dynamic, living tissue, just like your heart and muscles. Our bones are continually breaking down and rebuilding. The right bone loading forces through well-planned training, plus adequate hormones and bone-building nutrients will help your bones remain strong.

Eat enough energy

Consuming enough energy (calories/kilojoules) for training plus general body function is critical for optimal bone health. If you do not consume enough energy, this can reduce production of hormones including oestrogen and testosterone which play important roles in bone building. Signs of inadequate energy intake include decreased performance, poor response to training, irritability, depression, loss of strength, menstrual disturbances, reduced sex drive, illness and injury. Predicting your precise daily energy needs as an athlete is difficult. Ensuring you consume more energy on heavy training days, before, during and after key training sessions and during peak times of the training season are simple strategies to ensure you have plenty of fuel in the tank!

Eat enough carbs

There is emerging research demonstrating that low carbohydrate diets impair bone formation and increase bone breakdown in athletes. These effects can occur in as little as 6 days of carbohydrate restriction. Longer-term studies are required to determine how these changes to bone may affect the rate of bone injury in athletes. There are well-established guidelines regarding carbohydrate needs for athletes. Understanding how to translate these into every day eating is key to good performance but may also be critical to prevent bone injury and disease such as osteoporosis later in life.

Eat a diet rich in bone-building nutrients

Vitamin D and calcium are important vitamins and minerals for bone health. Vitamin D increases the ability of your small intestine to absorb dietary calcium. Calcium provides structure and strength to bone. Consuming enough vitamin D and calcium is suspected to be important for prevention of bone injury. Including foods rich in vitamin D and calcium and spending enough time in sunlight are key strategies for bone health. Vitamin D-rich foods include salmon, sardines, vitamin-D fortified dairy foods, cheese, eggs, margarine and sunlight-exposed mushrooms. Calcium rich foods include cow's milk, yoghurt and cheese, calcium-fortified dairy alternatives, almonds, legumes, tofu, seeds and some leafy green vegetables.

Summary

There is plenty you can do to reduce your risk of stress fracture. A well-planned diet with enough energy, carbohydrates, calcium and vitamin D can keep your bones strong so you can keep running!

Next step

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References

Bennell 1999, 'Risk factors for stress fractures', Sports Medicine, vol. 28, iss. 2, pp. 91-122.

Kerr, D & Larson-Meyer, E 2015, 'Bone, calcium, vitamin D and exercise', in L Burke & V Deakin (eds), Clinical Sports Nutrition, McGraw Hill Education, NSW, Australia, pp. 234-265.

Heikura, IA, Uusitalo, A, Stellingwerf, T, Bergland, D, Mero, A & Burke, L 2018, 'Low Energy Availability is Difficult to Assess but Outcomes Have Large Impact on Bone Injury Rates in Elite Distance Athletes', International Journal of Sports Nutrition and Exercise Metabolism, vol. 28, pp. 403-411.

Heikura, IA, Burke, L, Hawley, JA, Ross, M, Garvican-Lewis, L, Sharma, A, . . . McCall, L 2020, 'A short-term ketogenic diet impairs markers of bone health in response to exercise', Frontiers in Endocrinology, p. 880.

Mountjoy, M, Sundgot-Borgen, JK, Burke, LM, Ackerman, KE, Blauwet, C, Constantini, N, . . . Meyer, NL 2018, 'IOC consensus statement on relative energy deficiency in sport (RED-S): 2018 update', British Journal of Sports Medicine.

Wright, AA, Taylor, JB, Ford, KR, Siska, L & Smoliga, JM 2015, 'Risk factors associated with lower extremity stress fractures in runners: a systematic review with meta-analysis', Br J Sports Med, vol. 49, no. 23, pp. 1517-1523.