Medial tibial stress syndrome (MTSS), commonly known as ‘Shin Splints’, is a condition where people feel pain in their lower leg, typically towards the front and inside of the shin. Symptoms of MTSS usually present during or after activities that mainly involve running. Often there isn’t an injury or incident, but instead the symptoms develop slowly over time with increased activity or training loads. Initially symptoms may be uncomfortable and annoying, but people are generally still able to participate in their chosen sports/activities. However, if not managed properly, symptoms will continue to progress and the condition can become more significant and debilitating.
MTSS is predominantly caused by continuous strain, overuse and microtrauma of the soleus (one of the calf muscles) where it attaches on the inside of the tibia (shin bone) to a connective tissue called the periosteum. The periosteum makes up the outer layer of the tibia to which the deep soleus muscle fibers attach. The soleus muscle is a prime mover in the running cycle. It acts to plantar flex our ankle, which allows us to push off our toes. During running the soleus muscle can undertake muscle forces as high as 6.5-8.0 times our body weight (see Figure 1). Therefore, as you can appreciate, it is a hard-working muscle in sport!
Figure 1: Muscle Forces during Running (Dorn 2014).
Although there is some conjecture in the research world regarding the pathophysiology of MTSS, a strong contributing factor is thought to be irritation of the medial tibial periosteum due to overloading of the soleus. If not managed appropriately a bone stress reaction, due to increased bone loading, can occur.
MTSS can be clinically diagnosed through the patient’s history and performing a physical examination. Imaging is only required if other significant lower leg pathologies are suspected.
Risk Factors – Major causes of MTSS:
As mentioned above, MTSS typically presents as an exercise-induced condition associated with increased running loads. If we have large, sudden increases in our training volume and/or intensity, this can increase the stress on the soleus muscle and it’s attachment to the tibial periosteum exceeding the capacity/tolerance of these tissues. Ben Brockman, an Exercise Physiologist at Physiotas, wrote a fantastic article about managing training loads in the running athlete. You can find his article here for further reading.
Other major causes of MTSS include:
- An excessively pronated foot posture (ie. flat foot) – if the longitudinal arch in our foot flattens more than is optimal, it can result in increased pressure being placed on other structures in the lower leg.
- Strength – if the soleus muscle doesn’t have the strength/capacity to tolerate high running loads it becomes fatigued quicker, increasing the risk of injury. As mentioned above, there is a lot of force being produced by the soleus muscle.
- Mobility – if the range of movement in the ankle is restricted, it may increase the demand placed on the leg muscles. It is also important to consider the whole kinetic chain, including the hip and knee.
- Biomechanics – over striding (running with a low cadence) while running can increase the ground reaction forces placed on the ankle/leg.
- Environmental – running on hard surfaces can also increase the ground reaction forces.
Management of MTSS:
The management for MTSS can be broken down into two major phases. The first is the acute phase, which is the period immediately after the initial flare up of symptoms. The second is the strengthening/loading phase.
During the acute phase, your Physiotherapist will utilise a range of different treatment options to help settle your symptoms down. This can include icing, massage and taping, as well as providing advice on how to manage and reduce your short term running loads.
During the strengthening/loading phase, your Physiotherapist will progress through a range of exercises targeted at building up the strength of the soleus and other key lower limb muscles. The exercises in this phase will typically be done while weight-bearing in order to improve bone load capacity.
Typically strengthening exercises performed during this stage include a variation of the bent leg heel raise (see figure 2). Your Physiotherapist will also aim to introduce running and comfortable level impact exercises. It’s important that there is a healthy balance between time spent running and strengthening, with emphasis on rest in this phase.
Figure 2: Bent Leg Heel Raise (Single leg)
Every individual’s rehabilitation is different and guided by symptoms; severity of condition, risk factors (above) and context (ie. what sport are you aiming to return to). Therefore if MTSS is affecting your ability to run, play sport, exercise or even just walk, the sooner you see a Physiotherapist the better. To book an appointment at any of our six clinics call 6424 7511 today.
About the Author:
Liam graduated from the University of Queensland with honours in 2016. Liam’s areas of professional interest include all aspects of musculoskeletal physiotherapy. He recently traveled away with the Queensland under 18 men’s hockey squad as the team Physiotherapist for their national carnival.
His personal interests include spending time with friends and family, as well as playing football.