What are shin splints? The term “shin splints” is a general term associated with sore shins either on the inside of the shin bone (tibia) or on the outside. The proper medical diagnosis for pain along the inside surface of the shin bone is “Medial tibial stress syndrome (MTSS)”. This is the most common form of “shin splints”.
So, what exactly causes MTSS? Well, there is no short answer. The current consensus is that MTSS is caused by the inflammation of the periosteum. Wait a second…the peri what?. Ok heres some basic anatomy:
We (most of us at least) know that muscles originate from some bony landmark on one end, and insert into another bony landmark on the other end (usually via a tendon). Between the origin and insertion, the muscles are also connected to their respective bones via a thin layer called the “periosteum” (if not then our muscles would dangle around!). Sometimes when muscles are overused or subjected to extensive impact forces, micro tears can form in the periosteum,essentially displacing the muscle from the bone. The body’s natural defense system kicks in and causes the periosteum to become inflammed.
In the case of MTSS, two muscles have been associated with this condition. Thesoleus muscle and the tibialis posterior muscle attach on the distal end of the tibia (2-4 inches above the ankle). Exercises involving lots of running or jumping places alot of stress on the muscle-bone interface. The constant pounding of the lower extremities can result in MTSS, with symptoms including pain and tenderness. Many other factors could underlie or amplify the problem, with the most common ones being:
1) Biomechanical issues. When we strike the ground, our feet are designed to “pronate” which means to roll inwards. This helps with dampening the impact upon footstrike. Some runners, especially those who have naturally flat arches “overpronate” (ie have the foot roll too much inwards). When this happens, a tremendous amount of strain is put on the muscles.
2)Running on hard surfaces. This mostly applies to distance runners who run on concrete or hard trails. The harder the surface, the larger the impact forces.
3) weak soleus or tibialis posterior (more likely) muscles. Weaker muscles don’t dissipate impact forces as readily and therefore more strain is put on the muscle and its periosteum.
Like with most inflammatory injuries, warm up and gradual activity will cause the pain to subside. However, the pain relief is only temporary and exercising through MTSS is never the right treatment (take if from someone who had to learn the hard way)
So thats MTSS is a nutshell. The good news is there are ways to prevent or treat MTSS. The general rule is the sooner you recognize the condition and treat it, the more effective the actual treatments will be. So don’t ignore those stubborn pains, even if you can run through it! Stay tuned for information on how to treat MTSS and for my experiences with this runner’s peeve.