Shin splints are not a specific injury, but a general term for pain on the inside of the shin. Overtraining is the main cause of shin splints. However, there are a number of factors which increase your risk.
Medically reviewed by Dr Chaminda Goonetilleke, 10th Jan. 2022.
Shin splints pain is primarily an overuse injury. Therefore, to answer the question of what causes shin splints? Overtraining, especially running or jumping without giving your body time to recover eventually results in injury. In particular, increasing running mileage too quickly, especially on hard surfaces. Aim to increase no more than 10% mileage each week.
Running on your toes, for example when sprint training places additional stress on the lower leg. Make sure you apply ice after training to help keep inflammation under control.
Overpronation occurs when the foot rolls inwards or flattens too much. The arch of your foot collapses and the lower leg rotates inwards. This, in turn, increases the stress on the soft tissues of the lower leg causing pain and inflammation.
Oversupination is where the foot rolls outwards too much. If you think you have biomechanical issues then see a professional for gait analysis. This is where they assess how you run, either on a treadmill or using force plates.
Does incorrect footwear cause shin splints?
Make sure you have the right running shoes for your feet. Inappropriate footwear such as the wrong type of shoe for your running style is a common cause of shin splints. For example, overpronators need running shoes with a firmer midsole on the inside.
Supinators usually require a neutral shoe with plenty of cushioning. Another cause of shin pain is running shoes that are just too old and have lost their support and cushioning.
Is poor flexibility a cause of shin splints?
Poor flexibility, in particular, tight calf muscles and tibialis posterior muscle is a potential cause of shin splints. Stress on the soft tissues, muscles, and tendons of the lower leg increases when running. Stretching the calf muscles is an important part of shin splints rehabilitation.