Medial Tibial Stress Syndrome "aka Shin Splints” Part 1

What is medial tibial stress syndrome?

Let’s start by hopefully clearing up some confusion. “Shin splints” is not a proper diagnosis and means different things to different people. When you look in the literature you can find about 30 different diagnoses for shin splints. So when someone tells me they have “shin splints” what I hear is, “I have pain in my lower leg”. At that point, I need more information before arriving at any conclusion. It could be the muscle, tendon, connective tissue, bone, nerves, or arteries/veins that are causing the pain. In this blog, I am discussing “shin splints” as Medial Tibial Stress Syndrome or MTSS. This is one of the most common diagnoses for “shin splints”. So what is it? MTSS is a repetitive overload injury to the bone/periosteum. The periosteum is the connective tissue on the outermost layer of bone.

Whenever we run or work out, our tissues undergo microdamage followed by repair. If our body can’t keep up with the repair cycle, it can begin to accumulate microdamage. At the level of the inside shin, or medial tibia, this microdamage without repair can result in a painful stress reaction of the bone.

This accumulation of stress without adequate repair can be caused by a number of things like:

  • Training errors

    • Too much too soon

    • Incorrect training intensity distribution (I talk about this here)

    • Lack of recovery between sessions

  • Muscle weakness or imbalances

  • Biomechanical or form issues

  • Poor nutrition, sleep, or other lifestyle factors out of wack

Solid physical therapy starts with the right diagnosis.

As I alluded to above, there are a lot of things that cause pain in the lower leg that someone may call “ shin splints”, but in order to arrive at the diagnosis of MTSS a patient would present with:

  • Diffuse pain on lower 2/3rds of the inside shin that has gradually worsened over time

  • Predictable pain pattern where the pain is provoked with activity (usually weight-bearing) and does not “warm-up” as the activity goes on. Typically pain ceases when impact ceases.

  • If an MRI has been obtained there could be evidence of mild to moderate periosteal edema (Grade 1)

*IMPORTANT: Continued pain at rest after activity, pain in an area less than 2 inches, noticeable swelling/bruising, or Grade 2-4 bone stress via MRI could indicate a higher grade bone stress injury or stress fracture. This would require specific rest times for bone healing based on the grade.

*ALSO important: Trauma, calf cramping, pins, needles sensations, or pain that does “warm-up” with activity could indicate a different diagnosis.

Ok, let’s get down to bidness.

For mild cases (intermittent pain or just very slight symptoms) simple solutions can often do the trick:

  • Take several consecutive rest days and plug back with a conservative length run-walk

  • Reduce volume 50% and focus on easy running versus any intensity

  • Focus on turning your feet over a little faster at the same speed

  • Change to a softer surface like the track/treadmill for 1-2 weeks.

For persistent or highly irritable cases, we need to be more nuanced. Here are 2 key points that can get runners on the right track with MTSS

Key Point #1: Put the dirt back in the hole

Pain-free exercise is the goal with this condition. I know… I know… you CAN push through the pain. After all, you’re a runner and that’s what we do. With MTSS, pushing into pain will best case: prolong the recovery process, and worst case: progress the injury farther down the bone stress injury continuum. (Note: If we are getting technical, the jury is still out on whether MTSS exists on the path to a stress fracture or is a slightly different injury process. Some theorize the bone is in a hypermetabolic state. Either way, pushing into pain isn’t productive with this injury. I tend to treat MTSS like a bone stress reaction and see great results with this approach.

The simple example I teach patients is illustrated below. If our goal is to get back to normal i.e. level ground, we get further from our goal by pushing into pain with exercise.

 
 

Key Point #2: Find an entry point to loading

Each runner with MTSS will have a different level of tissue irritability and thus a different level of loading they can tolerate. A runner with MTSS should be pain-free with daily activities for at least 5 consecutive days before beginning targeted exercise. This could involve a period of complete rest (3-6 weeks) if things are very irritated. If this is the case, you would want to rule out a higher level of bone stress injury. If that is ruled out via an MRI and a runner is pain-free with activities of daily living for 5 consecutive days then it is safe to find an “entry point to loading”. This simply means a level of exercise that does not produce symptoms but loads the shins and lower leg.

In the clinic, I would take someone through a full orthopedic exam and loading tolerance test to find their ceiling of exercise that they can tolerate pain-free. For example, maybe a single-leg squat produces symptoms but a double-leg squat did not. In that case, a double leg squat would be in-bounds and be “putting the dirt back in the hole”. Or maybe a runner is tolerant of everything except running. I may have that runner do some jogging in place or pogo jumps to “put the dirt back in the hole”. We can also revisit the loading tolerance test after a few weeks of targeted exercise and a runner should be able to tolerate a higher level of loading without pain.

 
PMM for BSI's.png
 

Phase 1: Eat/Load/Repeat

Bone responds really well to a variable, high-frequency, low volume per session exercise program. To make it simple, I’d prescribe doing a different exercise for 3-4 sets after breakfast/lunch/dinner.

“Can I just do it all as one session?”

I know this is weird but here’s why…After about 100 loading cycles our bone cells become “deaf”. Meaning they no longer respond to that stimulus. Then after 4-6 hours, they are ready to go again. So by doing this protocol you can produce more bone adaptation than doing one long session.

Bone also responds to site-specific loading, in other words, loading the tissue with the issue. So for MTSS were are targeting the tissues of the lower leg with our exercises. As a rule of thumb, I like to target the calf muscles, entire kinetic chain/coordination, and an above bodyweight exercise in my initial program. Keep in mind the level of exercise is based on the findings from the orthopedic exam and the loading tolerance test (Key point #2) and needs to be pain-free during and after to be productive (Key point #1). See below for a sample program.

*Not a one size fits all approach.

Morning: Heel Raise (Calf muscles)

 
 

Mid-day Squat Clock Progressions (Kinetic chain/coordination)

 
 

Evening: Farmer’s Carry (Above body weight stimulus)

 
 

I hope this was helpful thanks for reading. Stay tuned for Part 2 where I discuss:

  • How to further bridge the gap back to running

  • Determining readiness to run

  • A sample return-to-run program

  • A few other important considerations.

Don’t hesitate to reach out with questions!

-Steve White, PT, DPT, OCS, CSCS

Steve White