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Shin Splints: What Causes Them and Why Do They Happen?

Updated: Mar 15, 2023

Shin Splints.

Medial Tibial Stress Syndrome.

A literal pain in your shins…

Take your pick of names.

Because whatever you call them, they're really, really, annoying

And sometimes, they take a really, really long time to completely go away (it could be 2 weeks; it could be 8 weeks.)

If you've ever had them, even for a week, then you know.

If you've been unfortunate enough to have them longer, then you're well aware of:

  • the frustration

  • discouragement

  • overwhelm

  • and nagging physical pain

  • It can get so bad, it can have a wild impact on your mental health (I've seen it).

The worse part: shin splints seem to have a mind of their own; staying calm and chill during base building and easy runs just in time to barge back in again when it’s time to turn up the intensity.

How come?

Who invited them to the running-party, anyway?

What are they?

And why do they hurt so badly?

Because it's shin splint season.
So let's de-mystify these party crashers get tools and resources into your hands so you can feel:
  • confident

  • strong

  • and resilient again when it's time to turn up the heat during your training cycle.

What are Shin Splints?

This is probably the ONE and ONLY part of shin splints or medial tibial stress syndrome (MTSS) that's actually straight forward.

When we look at the pathophysiology of MTSS, we know symptoms are:

  • a sharp pain

  • or an ache

  • that gradually increases in intensity with more and more activity

  • is potentially caused by the inflammation of the periosteum of the tibia.

Quick anatomy lesson:

  • Every organ in your body is surrounding by multiple, thin layers of "shrink wrap" or "saran wrap". Typically this is fascia or just very thin outer layers of the organ itself.

  • In this case, the periosteum is one of those thin layers surrounding the organ that is your bone.

  • The periosteum is SUPER important to the health of your bone as it's made up of different bone cells that do lots of different things…(I'll leave at that for now, otherwise we'll go down an entirely different rabbit hole..)

What happens with shin splints, is that particular layer of the bone becomes inflamed. And typically when tissues in our bodies are inflamed, they hurt.

But the real question is WHY.

Why do Shin Splints Even Happen?

Before you start jumping in and blaming mileage or speed works, check this out…

This over-use injury has been DEBATED for YEARS.

Old school thought is this:

  • shin splints happen because of an increase in load (here comes that increased mileage, increased intensity [hills OR speed work], running on hard surfaces, etc).

  • Scientists have also thought it could be because you're wearing the "wrong" shoe, or its old ankle issues, or maybe poor running form.

I mean, these aren't necessarily wrong, but they're not good enough.

Here's why.

  • Let's say you follow the perfect training plan, you have your perfect pair of running shoes, and your running form is the best ever (because you took the Running Form 101 Workshop)

  • You still end up with shin splints.

  • So what gives?

Ready for the plot twist?

The literature (all the science-y research papers) DOESN'T KNOW.


I kid you not.

Older theories as to how MTSS happen include these two:

  • Tibia Fascia-Traction Theory (TFTT) suggests that muscles apply too much of a traction force on the tibia and its periosteum.

  • Bone Stress Reaction Theory (BSRT) suggests that bone remodelling (think: bone healing) to repetitive stress is inadequate.

For years, paper after paper, scientists have speculated, theorized, hypothesized… but at the end of the day, one after another, each paper admits "majority of the (MTSS) literature is solely based on expert opinion."

That literally means sport scientists, MD, DPTs, kinesiology PhD's- it's all our best guess.

I don't say that to discourage you.

I'm bringing up this point to give you HOPE.

To tell you, your case or your situation isn't because you're broken or you're doing everything wrong or you're not doing enough.

NOT at all.

I'm telling you this because the science is trying to catch up with YOU. The closest explanation in recent science that I've found so far as to why shin splints happen, is this:

"MTSS are multifactorial…a spectrum of injuries including muscle imbalance, abnormal tibial loading, and chronic repeated stress…"

I know, that doesn't seem real helpful for the average runner. But I promise, it's the shift in the science that we've been waiting for.

Let's break this down.

Multifactorial: shin splints are kinda complicated. The reason(s) one runner got shin splints might not be the same reason(s) you got them. And that's ok.

Muscle imbalance: In my opinion, this is probably the most likely reason shin splints happen. We'll talk about this more below, but essentially, one muscle group is doing too much work while another group isn't pulling its weight. Essentially, the load of running is unbalanced.

Abnormal tibial loading: Speaking of load, because there are issues with each muscle doing the appropriate amount of work, this results in the tibia bone itself bearing the brunt of the work load. It's strong! Don't get me wrong, but it has muscles attached to it for a reason.

Chronic repeated stress: think about running-it's a repetitive motion, taking one step after another after another after…etc. When this kind of repetition happens on a tissue that is experiencing abnormal load without the appropriate help from it's surrounding muscles, that definitely results in too much, long term stress.

Want some further evidence?

Another recent study found that increased and/or excessive foot pronation resulted in increased EMG activity in the soleus and anterior tib. They also found that with baseline testing, athletes with higher soleus EMG activity were more likely to develop MTSS.

(in case you're interested: here's the paragraph…otherwise, feel free to skip because TL;DR)

"The SO (soleus) is attached to the medial calcaneus, and large and longer duration of traction forces associated with over-activity of the SO during supination in the propulsive period after over-pronation of the calcaneus upon landing may result in severe strains to the distal third of the posteromedial tibia. If, without proper recovery, this is repeated over and over again during running it may ultimately lead to MTSS. The high dynamic foot pronation in MTSS participants during running may be related to a modified alignment of the rear-foot bones along with less stable foot articulations and an increase of the tibial internal rotation during the stance phase. In turn, altered rear-foot bone configuration changes the line of pull for the SO muscle, requiring a higher activity of SO muscle to produce the same torque."

The trick though, is to again ask WHY??

Why is the soleus over-active?

This is the part where we have to leave the beaten path and start off-roading. This is where my "expert opinion" starts making a path through the weeds, based on what I've recently experienced in the clinic…

The Clinical Answer:

Why are you getting shin splints?

Because you're feet/shins are doing all the work.

You're overusing your feet.


From what I've seen of shin splints in the clinic, they appear to result from some of that multifactorial muscle imbalance resulting in abnormal tibial loading.

  • overuse of certain muscle groups and underuse of different muscle groups.

  • The runner's body seems to have a difficulty finding that balance of everyone (muscle groups) working together

There's also the possibility of mobility deficits:

  • poor hip mobility or

  • ankle mobility (range of motion)

I've also been noting some specific strength deficits, but it's not quite what you think it is…

  • Glutes

    • A runner's glutes could be genuinely weak,… OR

    • Their body doesn't always know HOW to access that glute strength.


Neuromotor control.

Your mind-muscle connection.

If you've ever taken any of my workshops than you know the almost "magic" like quality some of these neuromotor control exercises have.

One minute you're super weak.

The next, you're rock solid.

You didn't just gain muscle mass like *that!* (finger snap)

Then what happened?

We re-established motor control.

That exercise helped you access the strength you already have.

So, what sometimes looks like a strength issue, is actually a neuromotor control issue.

How does this fit into shins splints?

  • A runner's body has a hard time finding and accessing that glute strength.

  • Their body struggles to use it, while at the same time ALSO getting the core on board with activating anti-rotation core strength and stability.

But you're body can't send you a text message saying:

"So glute and core broke up again and aren't talking to each other.

You might need to have an exercise intervention and couples therapy to get them communicating again."


Instead our body says: "OH WELL! I GUESS WE'RE RUNNIG ANYWAY!"

As a result of poor communication in our bodies and us being task driven to succeed and actually run, our bodies "dump" this work in a last-ditch-attempt into our feet and shins when ideally, the load should be dispersed amongst various team members.
Again, multifactorial abnormal tibial loading + muscle imbalance+ chronic repetitive stress = MTSS

Wrapping up…

Hopefully you've emerged from the weeds a little enlightened.

Shin splints aren't cut and dry.

Or Black and white.

MTSS is definitely a runner-by-runner, case-by-case situation.

But the good news is, you're not alone.

And you can get better.

And there is hope.

Do you have questions still? Message me, email, reach out- I'm here to help!

In fact, if you're looking for someone to work with you one-on-one let's connect! Let's help restore your confidence and get you back to running.

Until next time, keep daring to train differently,

Dr. Marie Whitt //

P.S. Looking to kick shin splints to the curb before they even get started? Click HERE!



Guo, S., Liu, P., Feng, B., Xu, Y., & Wang, Y. (2021). Efficacy of kinesiology taping on the management of shin splints: a systematic review. The Physician And Sportsmedicine, 1-9. doi: 10.1080/00913847.2021.1949253

Kashi, O., & Minoonejad, H. (2022). The Comparison of Anatomic Alignment of the Shin, Ankle, and Foot in Elite Runners with and without Medial Tibial Stress Syndrome. Journal Of Clinical Physiotherapy Research, 3(2), 89-94.

Menéndez, C., Batalla, L., Prieto, A., Rodríguez, M., Crespo, I., & Olmedillas, H. (2020). Medial Tibial Stress Syndrome in Novice and Recreational Runners: A Systematic Review. International Journal Of Environmental Research And Public Health, 17(20), 7457. doi: 10.3390/ijerph17207457

Naderi, A., Moen, M., & Degens, H. (2020). Is high soleus muscle activity during the stance phase of the running cycle a potential risk factor for the development of medial tibial stress syndrome? A prospective study. Journal Of Sports Sciences, 38(20), 2350-2358. doi: 10.1080/02640414.2020.1785186

Sievers, M., & Busch, A. (2021). Medial tibial stress syndrome: The relationship between gender and lower-extremity functional performance among collegiate track and field athletes. Internal Journal Of Sports Medicine And Rehabilitation, 4(16). doi: 10.28933/ijsmr-2020-12-0805

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