The start of summer sport season tends to see us playing sports that can increase our susceptibility to shin pain. These sports can involve a high number of impacts (jumps, sharp stopping, change of direction and running) and be completed on hard/firm surfaces. This can include fields that may have hardened with exposure to warmer temperatures or different types of courts (tennis, basketball). The warmer weather also brings motivation to get out and hit the pavement on some longer runs. These are overall very positive things, but care must be taken, especially if we are coming from a low training base.

Not all shin pain is created equal. Shin splints are an umbrella term for at least three different conditions, each with different pathologies and pain patterns, but with similar causes. Often these conditions co-exist, particularly once they've been around for a few months. The diagnosis is less important than figuring out the reason that has brought about the onset of pain. The fix for your problem is in the cause, not the pathology.

Diagnosis and Pain Patterns

The most common diagnoses under the umbrella of shin pain can include tibial periostitis, tibial bone stress injuries (including stress fractures) and compartment syndrome. The pain patterns for each can be quite distinctive however, as mentioned above, the conditions often overlap, and the actual patterns may have elements of multiple conditions.

Periostitis is an inflammation of the outside of the bone, at the attachment of muscles and fascia. Periostitis is painful on initial weight bearing in the morning, painful at the start of a run but "loosens up" with distance (although it may worsen later in a long run) and returns post-run.

Tibial bone stress injuries occur when the rate of destruction of bone cells is not matched by the rate of new bone cell creation, leading to gradual compromise of the bone structure. This often occurs because of a sudden increase in training load or volume. Tibial bone stress injuries are also painful on initial weight bearing in the morning, painful at the start of a run and gets worse with distance. The duration of pain after a run can indicate the stage of the injury, from pain that resolves in a few hours (bone stress reaction) to pain lasting a few days or remaining constant (stress fracture), however this is only a rough guide.

Compartment syndrome is caused by an increase in pressure in one or more of the tibial (lower leg) compartments (anterior, lateral, superficial posterior and deep posterior compartments). These areas are sectioned off by strong fascia and can trap the rising pressure and compress structures passing through the compartment (eg. nerves, blood vessels). Compartment syndrome tends to worsen with distance during a run but resolves quickly after stopping. There is no pain the next day for isolated compartment syndrome, however it often co-exists with periostitis, which can cause pain the next day.

Causes

The causes of each of these conditions can be quite varied and multifactorial but there are a few common causes that are worth mentioning:

Foot Strike

Whilst running, the interaction between how our foot strikes the ground and the resulting forces that are transferred from our foot into our tibia will have an impact on our chances of developing shin pain.

Overstriding (lengthening stride) can lead to more of a heel strike whilst running. This typically exposes us to higher braking (or backward) force with minimal use of the force absorbing structures of the foot and leading to higher force being transferred through directly to the tibia.
Landing with our foot further under our body and more toward our midfoot allows the force absorbing structures of the foot to do their job and dissipate some of that force before it reaches our tibia.

The speed at which you are running dictates your interaction with the ground – running slower will typically elicit more of a heel strike, running faster will typically be more of a mid/forefoot strike.

Foot Pronation Control

Pronation refers to the action of the foot rolling inwards or flattening the arch. Multiple factors can contribute to poor pronation control and it's often a combination of factors that leads to an injury. Fatigue is a big contributor and occurs when a runner goes beyond their normal distance in a single run or in their weekly distance. It can also occur with increasing difficulty such as increased pace or more difficult terrain.

Old or worn footwear can also influence our foot mechanics and increase our chances of developing an injury. The average shoe lasts around 600-800km, but this figure can be reduced by heavier runners, runners covering larger distances in a single run or shoes that are used for running every day.

Training Load Spikes

The beginning of a new sport season can often see an increase in training load after a period of rest from the previous season. Load can be referred to in many ways and is dependent on your sport. If you are a distance runner, kilometres covered per week is the main measure of load. For team sport athletes, it can be harder to quantify your training loads but measures including number of sessions (on court/field) a week, length of sessions (time) across a training week can be simple ways to understand and monitor training loads.

Increases in training load are required for adaptation (getting fitter), but a gradual increase over a long period of time must be considered in order to minimise our chances of an overuse injury. This is especially relevant for sports that have high impact loading. These can include Basketball (jumping and landing, sharp decelerations and change of direction) and Touch Football/Rugby/Rugby League (high running load, sharp decelerations and change of direction).

Fixes

Once shin pain has started, it can be difficult to stop for multiple reasons. Some general guidelines when experiencing shin pain can be the following:

• Reduce your training load. Don't stop altogether if you can avoid it but reduce your training load to levels that don't worsen symptoms.
• Add some extra cushioning to your shoes. Before you throw out your shoes and buy a new pair, try adding a cheap foam inner sole to the shoe and see if the extra cushioning makes a difference.
• Start some strength exercises that can help with stability. Exercises targeted toward the small, stabilising muscles of the foot/shin complex can help with our foot mechanics and force distribution.
• Ankle mobility and calf length can also relieve some symptoms but can also be protective against developing shin pain.
• Avoid anti-inflammatories unless recommended by your health professional. These can mask the symptoms and may disrupt bone remodelling (healing).
• If in doubt, if it's not getting better or if it's been around for a while, seek medical advice. The earlier you seek advice, the easier the fix.