Here at Sport and Spinal Physiotherapy we see around 1-2 clients with a stress fracture per week. This may not seem like a lot, however it is a common overuse injury. We see this injury in distance runners, and athletes who participate in running or jumping sports such as netball, basketball and tennis. Quite often, this injury goes undiagnosed, and further injury can occur.
A stress fracture is a tiny break in a bone caused by repeated stress. This stress exceeds the bodies ability to heal. The injury is often a result of overuse and repetitive activity. It can also occur spontaneously in people with osteoporosis.
Effects of exercise on bone strength (density)
Bone strength is determined by its material and structural properties. The Bone mineral density (BMD) is a useful measurement of bone strength. Optimal bone density depends on a balance between bone formation and bone break down. If this balance is negatively disrupted, then BMD decreases and stress fracture risk increases.
Exercise can promote bone formation (osteogenic), especially sports that are high impact and multi-directional, such as soccer. However, some sports do not typically promote healthy bone formation. These include sports that are repetitive and low impact. For example, running and dancing, or non-weight bearing, such as cycling and swimming.
What factors increase the risk of a stress fractures
- Energy deficiency (not eating enough to match your energy expense)
- Low BMD
- Amenorrhea (female): Did you know that in a survey of Australian exercising women, less than half were aware that menstrual function impacts on bone health.
- Training errors (overtraining/exercise addiction, poor movement biomechanics, footwear, hard training surface)
How can Physiotherapy minimise your risk of training errors?
A physiotherapist will be able to minimise your risk by addressing several factors. These include loading technique, strength, footwear and training volume. For an example, in the distance runner we would assess:
- running biomechanics
- looking at factors that increase stress through the leg bones such as over striding
- increased adduction of the leg
- low cadence
- decreased ankle range
- gluteal and calf strength.
After our initial assessment an appropriate treatment plan will be put in place.
Common sites for stress fractures
- Arm (Humeral shaft)
- Pubic Bone (Pubic rami)
- Thigh (Femoral shaft and neck)
- Shin (Tibia and fibula)
- Heels (Calcaneus)
- Foot (navicular)
- Toes (2nd metatarsal)
Signs and symptoms of stress fractures
- gradual feeling a dull ache in one area. This can be aggravated by exercise and may ease with rest. However, pain can remain after exercise, at rest and even at night
- Tender to touch
- Pain with a bone stress test such as the fulcrum test and the hop/jump test
How to diagnosis a stress fracture
- Bone scan imaging and MRI are the gold standard diagnostic tools for detecting early signs and progression of a stress fracture.
- X-Ray imaging may detect a progressed stress fracture but is unable to detect early formation.
How to rehabilitate a stress fracture
1. Primary stage: management
Initial management includes a period of complete rest or a reduction in training volume. This depends on the nature of the stress fracture. More severe stress fractures may require the use of crutches or a boot. While you may have to limit your training, you can still maintain fitness by swimming or underwater running.
2. Secondary Stage: return to sport and future prevention
- For stress fractures affecting the lower legs, the expected time to return to exercise is approximately 12 to 13 weeks. However, it is recommended to consult with a specialist.
- Once you have the go-ahead, you should gradually return to training. Start slow and try not to increase the intensity or distance by more than 10% a week
- Address any biomechanical issues including running form and bike fit. This might entail a bike fit or a running assessment.
- Include weekly strength training. Strong muscles help to absorb the forces during impact activity. Click here to see an example strength program for management of tibial stress injuries (shin splints).
- Address any foot biomechanics. Increased foot pronation or high arches can contribute to added stress on the bones. A systematic review demonstrated that shoe insoles may prevent lower limb stress fractures by providing shock absoprtion. Seeing a podiatrist is a good start.
- Have regular 6 monthly BMD scans to monitor bone health. Referrals for a bone scan can be attained through a physiotherapist or your GP.
Why are females are a higher risk for stress fractures?
Females are at risk of the “Female athlete triad”. This is a combination of amenorrhea and low energy availability/disordered eating. This impact on our bone density and growth hormone release.
This condition was later redefined as “relative deficiency in sport (RED-S)” and includes male athletes. RED-S is a significant risk factor for stress fractures due to the impact of prolonged energy deficiency on bone health.
Signs of RED-S
- low energy availability
- substantial weight loss/ abnormally low body weight
- disordered eating
- low BMD
- menstrual dysfunction
- recurrent injuries
- decreased performance and mood changes
- Previous stress fracture
Management of RED-S
Prevention is key. Though less than 50% of health professionals and coaches are able to identify components of RED-S. These statistics refer to females in sport, and the lack of awareness of RED-S in males is even more pronounced.
- Education about healthy eating and nutrition in sport
- Monitor training load
- Develop goals aiming at performance and optimal health
- Enable access to all healthcare needs
- Follow RED-S return to play model (click here for more information on RED-S)
In summary, stress fractures are a common overuse injury in repetitive running/jumping sports. They are debilitating and consequently, can worsen or become reoccurring if not managed properly. Measures to prevent stress fractures include addressing nutrition, footwear, training volume/environment, biomechanics and strength. Treatment is multidisciplinary and includes a temporary reduction in training volume or complete rest, followed by a gradual return to sport supplemented with strength training, nutrition and footwear advice.