Shin Splints from the Periosteum
Have you had pain in your shin that does not go away with rest? Runners most often complain of shin splints especially those that run often on hard surfaces, a common enough situation here in Singapore. Unlike other injuries where you feel pain at the muscle, ligaments or joints, the pain from shin splints actually come from the bone in most cases; or more accurately, from the periosteum, a thin sheath that covers all bones whose function is to provide nourishment to the bones. This sheath is rich in nerve endings, so it feels pain. When the periosteum is over-strained and irritated, it gets inflamed causing pain. In the case of shin splints, it is the sheath covering the tibia.
What pulls at the periosteum?
Most of the muscles in the calf, ankle and foot attach directly to the shinbone. When these muscles do not work well or work too forcefully, it strains the periosteum covering the shinbone.
The usual causes of Shin Splints include,
- Pronation of your foot arch. When the foot over-pronates (over-rotate), the foot pushes almost entirely off the big toe, straining the big toe and the outside of the shin. When under-pronating, too much weight is borne by the outside edge of the foot, again straining the shin.
- The tightness of your calf muscles. A tight muscle cannot help absorb shock well. When taut, it transmits forces directly through to the connecting bone.
- Running with shoes with a lack of support or cushioning. The leg has to absorb whatever leftover forces the shoe fails absorb from each footfall. These leftover forces strain the muscles and connective tissues such as the periosteum.
- Running on hard surfaces. When the running surface does not give, more shock is ‘reflected’ back to the runner.
- Poor running biomechanics. The human body absorbs and dissipates forces through its skeletal and muscular systems. When this system does not function well through irregular running gait or a malfunctioning component such as a tight calf muscle, other parts of the system has to compensate and becomes overloaded over time.
Repeated strain onto the periosteum will lead to the inflammation, causing the pain.
Treating Shin Splints
The best way to treat a shin splint is to remember RICER (Rest, Ice, Compression, Elevation, and Referral). Completely rest and ice the painful region immediately when pain is first felt. Compress and elevate your leg above your heart if there is swelling and get a medical professional to review your condition.
For each of the above causes of shin splits:
- Pronation of your foot arch. Arch support or shock-absorbing insole is highly recommended.
- The tightness of your calf muscles. Sports massage to release the tight muscle.
- Running with shoes with a lack of support or cushioning. Get properly fitted with the right shoes. If unsure, a podiatrist, kinesiologist or sports physiotherapist can help you choose.
- Running on hard surfaces. Try to run on softer surfaces.
- Poor running biomechanics. A rehabilitation program which includes stretching your tight muscles, strengthening of muscles to correct muscle imbalance and correction of biomechanical abnormality in your running gait
A final word of warning, chronic compartment syndrome can also cause shin splints, where pressure builds up within the muscle and restricts blood flow. This requires immediate medical attention as restricted blood flow can lead to nerve and muscle death. Whenever any type of pain persists, it is always prudent to seek proper medical advice.