Shin Splints - Anatomy, Causes and Treatment
Shin splints is a name given to a musculoskeletal injury of the lower leg or shin, which can have a number of different causes. More specifically, shin splints is a pain due to adverse loading of muscles that attach on to the tiba (shin bone). This abnormal loading leads to muscle inflammation that causes the pain, but in worse case scenarios the tibial periostium (the shealth covering the bone that the muscle attaches to) can also become inflamed, leading to pain, tenderness and swelling about the shin during and after exercise.
Most commonly the injury affects the tibia, the tibialis anterior (muscle) or tibialis posterior (muscle). The function of these muscles is to control the foot position during exercise. Their main roles are to dorsiflex (or raise) the foot (so we don't kick our toes when we run) and to control our arch during weightbearing (to give our foot at better lever-arm for propulsion and to help with force or shock attenuation when our feet hit the ground). These muscles attach to the periostium, a thin laying or connective tissue (collagen) that covers our bone surfaces. The periostium contains many more nerve endings and blood vessels compared with the adjacent bone, making it a particularly sensitive and painful structure when it becomes inflamed from overloading.
Shin splints begin when the forementioned muscles aren't capable of handling the workload that the athlete is forcing them to do - essentially when the muscles are over worked. In the early stages of the injury, it's simply that the muscles are tired and sore. But should excessive activity or training continue, eventually the periostium becomes involved, causing much more pain and inflammation that unfortunately takes longer to heal then if it were a muscle injury alone.
So what causes the overloading of the muscles? From my professional experience as a physiotherapist treating this injury - there are 3 main factors.
- Excessive/Over Pronation: Pronation occurs when our arches flatten out, this is a normal process and part of the method how our feet absorb the contact pressure from the ground when we walk or run. The job of our tibialis posterior muscle however is to hold our arch up, so if during activity our arch flattens too quickly or too forcibly, this causes overloading of this muscle. This biomechanical issue of over pronation can be caused by tight calf muscles or inappropriate footwear with poor arch support.
- Excessive Training: There may not be problems with your biomechanics, but if you're not training appropriately you may run into problems. This not only includes just over training (having inadequate rest and nutrition between sessions), but when you change your training methods your body finds it harder to adapt, so your muscles work harder as they condition themselves to the new style of training. This includes training at new intensities, longer durations, training on a new surface, new footwear or even just adapting to a new sport. Sometimes is not only when you make your training harder, we occasionally see problems when you reduce your training load, as this will also cause reduction in the strength or flexibility within the muscle that can produce repetitive overloading.
Poor Core Strength: Issues further up the limb may also manifest themselves into injuries in other regions of the body. Weak muscles around your pelvis, knees or over your lower back can place extra stress and strain through your lower limbs as the weak areas struggle to cope with training loads placed upon them, with your body then compensating and placing the stress on other areas.
Treatment for Shin Splints:
- Address any calf muscle tightness - usually with massage and stretching
- Address any other muscle imbalances - including a core or lower limb strengthening program, massage to the lower limb or have a professsional look at your running style
- Address any over-pronation problems - either with appropriate footwear or with a podiatry assessment (whom may prescribe orthotics, a custom made insert for your shoes to assist in your arch support). Your podiatrist, physio or sports trainer may also strap you feet in a particular method called a "Low Dye", which helps to hold your arches up. This will reduce considerable pressure from the shin muscles while you exercise, and should be the first step prior to getting orthotics.
Low Dye Strapping Method
4. RICE regime (that stands for Rest, Ice, Compression, Elevation)
5. Have your training regime/routine assessed by a professional
If that fails, please see a sports professional as many other conditions can be masquerading as shin splints (some of these include stress fractures, compartment syndrome or referred pain from a back condition).