11 Causes Of Shin Splints In Runners

11-Causes-Of -Shin-Splints-In-Runners

What exactly are shin splits?

Well, apparently there’s no clear consensus among sports scientists of what shin splints actually are. It can be small tears in the muscle that’s pulled off the bone, an inflammation of the periosteum [a thin sheath of tissue that wraps around the tibia, or shin bone], an inflammation of the muscle, or a combination of them.

Collectively they are referred to as MTSS – Medial Tibial Stress Syndrome.

According to the NHS shin splints is the name for pain in the shins, or the front of the lower legs, usually caused by exercise.

In The Runner’s Body, Ross Tucker and Matt Fitzgerald define shin splints a symptom, rather than a diagnosis, of the many potential injuries of the tibia.

According to Runner’s World shin splints make up about 15 percent of running injuries. Although the numbers are from 2011 they still give us an idea of how common these injuries are nonetheless.

Shin splints are among the most common injuries. The tissues are more prone to injury in beginner runners and runners who return to running after a break because the bone and muscles are not yet conditioned. So the unconditioned or de-conditioned runners. We will talk a little bit more about this later in the article.

The most common site for shin splints is the medial area (towards the inside of the shin) – medial shin splints. Overpronation is a common cause of medial shin splints.

Anterior shin splints (toward the outside of the leg) usually result from an imbalance between the calf muscles in the back and the muscles in the front of your leg. The anterior shin splints often affect beginners who either have not yet adjusted to the stresses of running or are not stretching enough.

The anterior shin splints may also be compartment syndrome and nothing to do with the bone, which we will talk about later in the article. Pain around the shin can also be a sign of a stress fracture.

But let’s go through the causes of shin splints to get a better understanding of why they happen and what actually happens.

 

Causes of shin splints in runners

 

1. Progressing or upgrading your training too fast, too soon

A progression of your training programme above the level you are currently at that’s too fast or too much can put your body under too much strain all of a sudden.

Whether you are a runner or not, bone tissue continuously breaks down and is being rebuilt, that’s how bones work. When you begin a running programme this process accelerates due to the repeated impact. Now, that’s a good thing. Impact exercise does build stronger bones, when done properly (this doesn’t apply to people who have health conditions or certain injuries though, one must assess very well whether impact training if for them).

The good news is that the existing bone tissue is broken down and a denser, stronger bone tissue is formed. This is the work of osteoclasts (breaks down bone tissue) and osteoblasts (makes bone tissue).

The bad news is that the bone must first be weakened before it can be strengthened. Runners who do too much, too soon, increasing their mileage too quickly or jumping into long mileage from the beginning, develop small bone fissures that cause pain. If the pain is not managed properly and on time, once the small fissures pass a certain point a stress fracture may result.

In the 2nd article on shin splints I will come back with ways to train through the shin splints (if possible) and/or how to best manage and home treat them so you can get back to training.

 

 Running form

Danny Dreyer, author of Chi Running, attributes “almost all running injuries to the current running paradigm of running, which [he] calls power running”.

Other well knows running coaches and authors share his view, such as Nicholas Romanov author of The Pose Method Of Running, and Danny Abshire author of Natural Running.

You can and should take time off to recover from shin splints, then strengthening and stretching. However, if you’re using the same running form that created the injury in the first place, that muscle will eventually tire, and you’ll end up with the same injury again and again. The way to heal any injury, after you recover of course, is to address the cause(s) that result(s) the symptoms. That cause might be hidden in your running form.

Danny Abshire talks about impact and rotational forces which cause shin splints as well as many other injuries. This too is associated with power running. We will talk about this later in the article.

And since we’re talking about power running, Malcolm Malk, author of the Art Of Running and Alexander Technique practitioner, also advocates a lighter running style, stating that “runners who pound the ground often end up injured”. In the list of do’s and don’ts Malk points out not to push the body up or push off with the feet. This is power running in a nutshell: pushing off and pounding the ground.

Running form may be the cause, but how do we know what aspect of the running form causes shin splints? Don’t worry, I’ve got you covered. The running form aspects that can cause shin splints are:

  1. Landing ahead of the body
  2. Heel striking and over striding
  3. Landing on the toes

 

2. Landing in front or ahead of the knee joint or landing in front of the body

This is a major running technique mistake identified in The POSE Method of Running and mentioned again in Nicholas Romanov’s Running Revolution as well as in other speciality books.

Landing ahead of the body causes the lower leg to land at an angle to the ground instead of perpendicular (which it would if the foot would land under the body or under the hip). Landing at an angle also causes stress fractures and compartment syndrome (which is the tightening of the muscles in the front of the shins).

How do you know it’s compartment syndrome or bone related pain? If it’s bone related you would feel pain when you push on the bone, the shin bone becomes sensitive to touch. If the pain feels more like tightness, which usually comes up while running and when you don’t run you are ok, it’s probably muscle related. This is a general guide so it’s good to check with a therapist or GP to get a diagnosis.

Landing ahead of the body, at an angle to the ground, creates a shearing effect on the shaft of the tibia bone when load is applied. Your joints aren’t designed to accept and hold (the load), but rather to accept and unload, so they get damaged in the process.

When we land ahead of the body we have to wait with the support foot on the ground until the upper body and GCM (general centre of mass) pass over the support leg. You may think it’s fast, but not for your support leg which needs to wait and hold the load until it’s able to unload. When you land straight under the body, your GCM is already over the support leg so there is much less waiting, you can unload almost straight away.

Furthermore, landing ahead of the body, known as active landing, also results in increased impact during landing, compared to landing under the body. This impact produces a shaking effect through the bone and muscles and leads to a separation of the periosteum tissues (a dense fibrous membrane covering the surfaces of bone) from the bone.

Some runners do have stride mechanisms that expose their legs to higher impact forces and a higher risk of developing tibial stress fractures.

 

What to do?

Consider shortening your stride to reduce the severity of impact.

Instead of placing your foot in front of your body try landing under the body or under the hips, which is the same thing. Shortening the stride will allow you to land under the body/hips.

From my work with runners I noticed that when they try to shorten the stride they shorten it so little that it makes no real difference. They don’t know the feeling of a shorter stride.

The feeling you are looking for is as if you are running on the spot. Exaggerate in your running technique drills, shortening your stride to half your normal length. After a few weeks or exaggerating the drill, relax your stride and it should be just right.

We will talk more in depth about this, and I will share some pictures and videos in the next article on how to manage and home treat shin splints.

 

How to check whether you’re landing ahead of the body if there is no one to watch you

If you have a friend or a coach who can look at you while you run it’s great. But what if you are alone and you don’t know the feeling yet? How do you check?

When you run, and if it’s safe for you to do this, use your peripheral vision and see whether you can see your feet when you run. Don’t bend your head or from the hips, and don’t lean forward, just take a quick peek. If you can easily see your feet, you are landing in front of your body. If you can see just a little bit of your toes you should be just about right.

 

3. Heel striking and over striding

There are three primary causes of many injuries including shin splints but also plantar fasciitis, Achilles tendonitis, iliotibial band (ITB) issues and patellofemoral pain syndrome. Those three primary causes are:

  1. impact forces from braking with a heel striking gait
  2. rotational forces from the same kind of gait
  3. the subsequent excessive force necessary to push off the ground to begin a new stride with that kind of gait

 

What is a gait?

Whether you walk, run or sprint your feet make contact with the ground in certain positions, causing the rest of the body to react and adjust to this movement. Your body continuously seeks out an ideal balance with gravity so it continuously checks and adjusts. How the feet land and their position is essentially the gait.

Whether you stand, walk, run or sprint the feet and brain are constantly talking to each other. The feet send signals to the brain and the brain repositions the rest of the body accordingly so you don’t fall over.

There are 3 types of gaits. We won’t go into a lot of detail now but these are: the walking gait (heel strike), the running gait (midfoot strike) and the sprinting gate (toe strike).

 

Landing and take off

Let’s think of running as formed of two phases: land and push off (or propulsion). The running movement is more complex that that but it helps get the point across if we simplify it to these 2 phases.

We will later learn that push off should be a pull and not a push, but for the sake of understanding the breaking and propulsion actions let’s think of running as landing and pushing off.

The muscles on the front of the leg are considered breaking muscles (tibialis anterior, quadriceps), the ones on the back of the leg are propulsive muscles (hamstrings, calves).

Your tibial muscles are on the front, so when you repetitively and continuously “break” or interrupt your running momentum by landing ahead of the body (over striding), and heel striking (the landing phase) you absorb too much impact. After landing you then use too much muscle power to maintain forward momentum (the propulsion phase).

Rotational forces and breaking impact increase when over striding and heel striking and lead to overuse injuries.

Excessive propulsion can create problems with hamstrings, Achilles tendon, and connective tissue in the lower leg, ankle and foot. When you land ahead of the body and heel strike – breaking you momentum, you automatically need to push off hard to move forward. You basically slow down and re-start with every step. There is no flow, but a constant break and re-start. It’s like a driver who hits the breaks every 10 seconds, break – accelerate – break-accelerate etc, but you do it every second. That’s what’s happening in your body at a smaller scale, whether you feel or not.

These breaking and propulsion motions create high impact, longer stride and vertical push (the bouncing feeling you get when you push off and up). When running like this you are isolating the breaking muscles on landing and isolating propulsive muscles on takeoff.

Impact forces are caused by the hard impact of a heel striking gate, while the excessive rotational forces happen at foot and ankle. As the foot and ankle rotate, the twisting motion continues up the body and results in traction forces on the sheath (periosteum) surrounding the shinbone. This cause inflammation of the sheath, which a type of shin splints as mentioned at the beginning of the article.

 

4. Toe landing

Landing on your heels is heavy, high impact and leads to injuries, but landing on your toes can also lead to injuries. I often see runners who mistake “ball of foot” or “mid foot strike” with running or landing on their toes. It should actually be somewhere in between.

Think about landing on the balls of your feet and then swiftly tap the ground with the heels. This way you don’t bounce around on your toes, nor do you hit the ground with the heels to heavily.

When your body weight is supported by your toes, the shins and calves workload increases.

When you land on your toes you probably also push off your toes in the propulsion phase, which we have already talked about in the previous section.

 

5. Inadequate muscle flexibility and mobility

Inadequate stretching leads to many injuries including anterior knee pain and Achilles tendonitis. This much is already known and everyone agrees stretching is important.

What type of stretching and when to stretch and which are the most effective stretches is a debate, but we all agree we need to stretch. I believe the debate is a debate because no runner is the same, having had the same training history and injuries, so the stretching routines will, of course vary, to a certain degree. The fundamentals are the same though.

It is more or less agreed that, for runners, static stretches at the beginning of the running session are not likely to improve performance. The runner’s muscles need to be ready to “fire up”, to rapidly stretch and contract, so a dynamic stretching routine is best at the beginning of the workout (i.e. butt kicks, high knees, side shuffles) and leave the static stretches (the ones you hold) for the end of the session.

There really is no way around it. Runners need to stretch on a regular basis, like brushing your teeth. And we also need to have the patience for it.

To land mid foot you need to be able to land with the foot roughly parallel to the ground. If your calf muscles are so tight that you cannot flex your ankle upwards to land with the foot parallel to the ground, you will either land too far up on your toes and push off hard in sprinting fashion, in the propulsion phase, straining your calf muscles and Achilles tendon, or you will use the opposite side of the leg muscles, the anterior tibialis (tibia muscle), to lift the toes and force the ankle to dorsiflex, causing shin splits.

Tightness in the calf muscles also causes the foot to overpronate which is a cause of several injuries.

 

6. Dorsiflexion

Dorsiflexion is when runners pull their toes towards their shin and the shin muscles contract. Doing this 10, 20, 30 times is fine, but doing it 10 000 times in one run, several times a week can strain the muscles and lead to pain in the lower leg.

Ensure your calf muscles are loose enough to allow you to dorsiflex. Your ankle mobility also needs to allow for dorsiflexion.

 

Testing your ankle mobility:

  1. Place the tested foot about 4 inches (10 am) from a wall.
  2. Make sure your foot is straight with toes pointed forward.
  3. Attempt to get your knee to touch the wall without lifting the heel or letting your knee move in any direction than forward.
  4. If you can touch the wall without the knee buckling in or shifting out and with the heel on the ground you have pretty good ankle mobility.
  5. Test on both ankles and mark with a couple of pieces of tape (one for the left foot, the other for the right) how far from the wall you are so you can test again after you attempt to improve ankle mobility.

 

7. Over-pronation

Over-pronation, when the foot rolls in excessively, is a common cause of shin splints (as well as knee pain). Over-pronation causes the tibia to twist and the muscles in the lower leg to overstretch. This causes inflammation of the soft tissues that attach to the tibia.

The pain is usually felt on the lower inside part of the leg, near the midpoint of the leg – medial shin splint. But the pain is not local, you may feel the pain in other parts of the leg as well.

 

8. Excessive Supination

Supination is the opposite of pronation. Supination is the foor arch is very high and you walk on the outside of the foot more or less. This is a more rigid foot and doesn’t absorb shock very well. It also transfers more of the impact up the leg causing the pain to be felt on the shin, usually on the bottom half of the shin.

 

9. Weak tibialis posterior muscle

The Tibialis Posterior supports the medial arch of the foot. It is responsible for keeping the arch of the foot when you bear weight on the foot.

When the Tibialis Posterior muscle is loaded more than it can handle, the muscle becomes tight and causes pain around the lower medial shin. In this situation we need to stretch as well as strengthen the Tibialis Posterior muscle and I will share with you some exercises to do this in the next article on shin splints.

 

10. Surface

Running too much on hard surfaces, on cambered roads or running in the same direction on the track, which places the stress on the same side and place over and over again, can also cause shin splints.

 

12. Footwear

Worn out shoes lose their support. Search for shoes that support your foot.

If you have flat feet you want shoes that control the foot motion. That is a shoe that has a rigid sole from the base of the toes to the heel, with a solid heel cup. As it acts as a brace for the foot it can help prevent pronation.

If you have a high arch, your foot is already rigid, so you are looking for shock absorption rather than motion control.

You can combine good shoes with a running techinque assessment to find out how you can tweak your form to reduce the impact force even more.

All shoes should have a flexible toe region to prevent overworking the muscles in the calf during activity and causing other types of running injuries.

 

Do any of these causes of shin splints ring the bell? Do you think any of them lead to your injuries, or maybe other reasons? Leave a comment below and let us know.

Look out for the next article on shin splints where I will share exercises and running technique elements help you to manage, treat and, preferably, prevent shin splints.

 

Sources:

  1. Sam Murphy and Sarah Connors “Running Well”
  2. Danny Dreyer with Catherine Dreyer “Chi Running”
  3. Nicholas Romanov “POSE Method Of Running”
  4. Nicholas Romanov with Kurt Brungardt “The Running Revolution”
  5. Ross Rucker and Jonathan Dugas, Runner’s World “The Runner’s Body”
  6. Danny Abshire “Natural Running”
  7. NHS
  8. Runner’s World
  9. Mayo Clinic
  10. Britannica
  11. https://www.runnersworld.com/shin-splints
  12. https://www.chirunning.com/blog/entry/the-whole-story-on-shin-splints
  13. https://entirepodiatry.com.au/information/injuries/shin-splints/
  14. https://www.runningshoesguru.com/2014/05/running-shin-pain-tibialis-posterior-stretching-strengthening/
  15. https://www.issaonline.edu/blog/index.cfm/2012/10/1/could-your-shoes-be-giving-you-shin-splints-