Shin splints explained for runners
The causes of shin splints in runners
Shin and calf pain can be frustrating for the runner and can often be difficult to treat. Such injuries can plague the runner for a prolonged period of time, meaning that expert help should be sought early on to ensure correct diagnosis and appropriate treatment is administered to get the runner back on track as early as possible.
The lower leg is composed of two bones — the tibia and fibula — and four muscle compartments bound by a strong tissue called fascia.
Consider this cross section of a right leg, looking down towards the foot:
Runners commonly experience shin pain and bracket this under a common term 'shin splints', but this term is not actually particularly helpful as there are several different running conditions which can cause shin pain:
- Medial tibial stress syndrome (MTSS)
- Tibial stress fracture
- Chronic compartment syndrome (CCS)
- Calf sprain
It is important for the physiotherapist or sports medicine practitioner to identify which of the four above it is to ensure the right treatment is administered.
What is Medial tibial stress syndrome what are its symptoms?
This is the kind of pain experienced by the runner in the shin which is brought on by running, and then takes hours or even days to subside. There is tenderness over the inner border of the lower two thirds of the tibia which is due to a 'stress reaction' of the lining of the bone on the inner border of the tibia, where the posterior tibialis muscle attaches. It often occurs in circumstances where there are abnormal biomechanics, such as overpronation, but it can also occur if there has been excessive running on hard surfaces and or or if trainers are especially worn out.
Treatment for Medial tibial stress syndrome
Treatment consists of a break from running while maintaining cardiovascular fitness through other activities such as cycling and swimming. Hands on treatment may include ultrasound, interferential, flexibility and strength work for the calf, achilles tendon and ankle.
It is important that any biomechanical abnormalities are addressed, and a sports orthotist may be called upon to do this. They will work in conjunction with the physiotherapist to help identify any changes in training that need to be made to avoid the condition recurring. A stress fracture of the tibia needs to be ruled out, so if your therapist is suspicious of one, it is vital that they organize an x-ray or a bone scan.
What is a tibial stress fracture and what are its symptoms?
A stress fracture is a bone injury caused by overuse. The repetitive strain of running causes bone trauma on a microscopic scale which left unchecked can progress to a stress fracture.
As with MTSS there is shin pain during a run which carries on after the run is completed. As the injury progresses, the pain starts earlier and earlier in each run and often lasts much longer after each subsequent run. A wave of pain may be felt at night when in bed after a run. A localized tender point over the fractured area of the tibia will be present, and this will show up on any bone scan.
Treatment for tibial stress fractures
Treatment is very much dependant on which part of the tibia is injured. Typical procedure is complete rest from running for 6 to 8 weeks. This should be followed by a gradual return to running, at first alternating low mileage running with non-weight bearing activities such as cycling or swimming. The intensity of activity should only be increased if the leg remains pain-free.
As with any injury of this nature, any biomechanical abnormalities should be addressed and the pre-injury training program needs to be looked at. The time taken for a stress fracture to heal can vary from individual to individual. In some cases, it may be necessary to immobilise the leg in a plaster cast for a short period.
The bad news for women is that stress fractures are more common in female runners. Often due to overtraining, it can also be due to low body weight, amenorrhoea (lack of periods) and osteoporosis (bone thinning). These factors should be address by a doctor rather than a sports therapy practitioner.
What is Chronic compartment syndrome (CCS) and what are its symptoms?
CCS occurs when the pressure within one of the muscle compartments of the lower leg increases during exercise, to the extent that the blood supply in the small vessels is reduced and the muscles (and sometimes nerves), in that compartment are compromised.
It can be caused by an increase in the size of the muscles which become too big for the inflexible surrounding fascia. This type of problem is most common in the anterior and the deep posterior compartments and may be associated with oversupination or overpronation respectively.
Treatment for Chronic compartment syndrome (CCS)
Symptoms of CCS typically occur during a run and are usually relieved by rest. The pain may feel like a cramp, a tightness or even a burning sensation. Often the specialist is unable to find an abnormality on examination as the symptoms are only present during actual exercise. Special pressure tests therefore have to be carried out while you are running to obtain a diagnosis.
Rest may ease symptoms of CCS, but they tend to return with each resumption of training, and the option then is surgery which involves the opening of the compartment (fasciotomy).
N.b. CCS is different from acute compartment syndrome, which occurs after trauma and requires immediate attention. Acute compartment syndrome is not discussed here.
Symptoms and treatment for calf injury
A tear of one of the superficial calf muscles (gastrocnemius or soleus) is best treated initially by RICE (Rest, Ice, Compression, Elevation). Early physiotherapy treatment is recommended and is similar to that required for an achilles tendon injury.
As with most injuries, prevention is better than cure. Make sure you warm up thoroughly before exercise, and spend sufficient time post-run stretching the calf muscles, and the other leg muscles.
Some of the other causes of lower leg pain in runners
- Referred pain from the lower back.
- Local nerve compression.
- Rarely, entrapment of the artery at the back of the knee.
As a final word, it is always worth remembering that any lower leg injury occurs for a reason. By looking to address the causes, and not just the sytmptoms of the injury, should mean a you can avoid a repeat injury in future.