Traditionally, the term 'shin splints' was used to describe any prolonged or recurring pain between the knee and the ankle, especially in athletes. The pain came most often from an overuse injury, which is ironic since the term itself was overused. Nowadays we have a better understanding of sports injuries, so shin splints is a blanket term used to describe conditions of the lower limb such as compartment syndromes, stress fractures and medial tibial stress syndrome (MTSS). It is used most often interchangeably with the latter. But regardless of what you call the condition, what can you do to prevent it?

MTSS is a common overuse injury frequently occurring in weight-bearing sports in which the participant's feet are repeatedly striking the ground. Examples include middle- and long-distance running, jumping events, basketball, football and dancing. It is characterised by pain from the middle to distal end of the posteromedial border of the tibia (shinbone). Pain occurs during exercise and subsides with rest. At first it may be possible to train through the pain but this will only worsen the condition and eventually it may be impossible to walk without pain. At this point the injury has turned into a stress fracture.

With any injury the causative factors should be addressed first; this will avoid making the condition worse and reduce the likelihood of the injury recurring. Krivickas (1997) indicated excessive pronation as the primary factor associated with MTSS. If the foot is allowed to pronate excessively, it alters the weight-bearing properties of the foot. It then becomes less efficient at absorbing shock and instead transmits the force of the impact to the tibia. This then places the athlete at greater risk of injury. During normal running, the soleus (the muscle in the lower part of the calf) works eccentrically to control the foot as it makes contact with the ground. If the foot is allowed to pronate excessively, the eccentric work performed by the soleus increases. This increases the tension of the soleus at its origin on the tibia, which in turn may result either in microdamage to the connective tissue that attaches the soleus to the tibia or in inflammation of the periosteum (surface layer of bone) at the point of attachment. Either of the these will result in the pain commonly called shin splints.

How can you prevent shin splints?
If you have experienced this type of pain either during or after exercise, you first need to ask yourself whether you have changed anything recently, especially training methods or equipment. In many cases, it may only be a small change that makes the difference between a pain-free and a painful training session.

Noakes (1991) believes that many novice runners who develop shin splints within the first three months of running can be cured by changing their running shoes. Look at the wear on the soles of your shoes - are they worn more on the inside, especially at the middle to front of the shoe? If so, you may be over-pronating. You would be advised to get a pair of trainers that are suited to your feet. Some good running shops offer a computerised foot-scanning service that will help you find the appropriate trainers. An over-pronater needs a running shoe with good support, particularly along the medial longitudinal arch. If you have a different wear pattern, it is still wise to have your feet examined because a shoe that is too rigid can also cause injury.

Avoid these training errors
Perhaps the second most common cause of overuse injuries are training errors. What surface do you run on most? If you regularly train on hard, tortuous pavements, especially if there is a slight camber in the surface, then stop. Vary your running terrain. Running the same route week in week out, especially on hard, unyielding surfaces, uneven ground or too many hills can trigger MTSS. This may sound difficult to manage, but the key is variation. Vary where you run, how far and how fast you run and most important vary the surface you run on. For athletes such as dancers or gymnasts, who perform their activity indoors, training on a sprung floor will help to decrease the stress of repetitive impacts on the lower limbs.

Another training error is doing too much too soon. This can happen to the novice individual wanting to get fit or lose weight as well as to the experienced athlete early in the season or when returning from injury. The body will adapt to the demand you place on it but not as quickly as most people would like. You need to be patient and listen to your body. If you start to feel pain in the lower leg, then it may be an early sign of MTSS or other overuse injuries. A simple reduction in running mileage or training duration may be all that's needed to stop the pain.

An athlete with poor running mechanics will also have increased risk of lower-limb overuse injuries. A narrow running gait or feet that cross over when you run can increase foot pronation and thus stress to the tibia and soleus. In addition, too long a stride or pushing off too hard with the toes can increase stress on the lower limbs. Get a colleague to film you running and assess your running gait.

This is by no means an exhaustive inquiry into the causes of MTSS, but it does highlight the simple key factors that you can alter easily to reduce the likelihood of injury or help in recovery. Other factors that have been pinpointed as likely to increase the chances of MTSS include menstrual abnormalities, low-calcium diet, muscle imbalances, inflexibility, hereditary factors, cold weather, insufficient warm-up and skeletal structural abnormalities.

Karl Halliday