How To Eliminate Shin Splints
Shin splints can be a very frustrating injury. I, Dr. Sarah, know this firsthand as I’ve experienced it multiple times myself. In fact, I’m training for a half marathon right now. And, I’ve been diligent about keeping up with the proper strengthening exercises so my shin splints don’t come back.
When it comes to shin splints, there’s external contributing factors and internal contributing factors. External factors are causes from outside the body and internal factors are causes from inside the body.
Sometimes there’s only one factor that leads to shin splints and other times there are a combination of factors. Regardless of how many factors there are, addressing all contributing factors is key so that shin splints resolve. In this blog post, we’re going to cover the most common external and internal factors that lead to shin splints. Here’s the breakdown!
Shin Splints: External Contributing Factors
The two main external factors that contribute to shin splints are improper footwear and sudden changes in mileage. Most of the runners we see develop shin splints due to the latter reason.
By improper footwear, we mean shoes that are too old or worn out. Running shoes have a lifespan of about 500 miles. Once you hit 200 miles, your running technique starts to change as how your shoe responds to the impact of your foot hitting the ground changes. When your running technique changes, your chance of injury increases. At 400-500 miles, about 40-50% of the shoe’s cushion is worn out and you’re in need of a new pair.
Your running shoes should also be fitted properly. If you aren’t familiar with how running shoes should fit, we suggest asking a physical therapist who specializes in working with runners (that would be Dr. Emily) or someone who fits running shoes on a regular basis. When people ask where to go, I typically suggest Performance Running Outfitters. It’s the store I go to for all my running needs, especially as I’ve been preparing for my half marathon.
The number one cause of injury in runners is due to increasing mileage too quickly. In general, you want to slowly increase your distance over time. The 10% rule is a good rule of thumb to go by. It says that each week, your total mileage should not increase by more than 10% of the previous week’s mileage. There are a few exceptions to this rule, and we discuss them in this video.
The classic example of a sudden mileage change is a high school cross country runner who doesn’t train at all over the summer and goes straight to running five days a week when school starts. While some runners can squeak by without injury with such a sudden volume change, some cannot and develop shin splints (or a different injury) in the process.
Shin Splints: Internal Contributing Factors
Internal contributing factors for shin splints come from two sources – decreased strength and decreased mobility. Typically, decreased strength is more common as runners usually focus more on stretching than they do strength training.
When Decreased Strength Leads to Shin Splints
There’s three main muscle groups that can have deficits when it comes to shin splints –
- Achilles (Gastrocnemius & Soleus)
- Tibialis Posterior
- Tibialis Anterior
We’re going to dive into how you know if you have weakness in any of those muscles. Once you’ve identified your weakness(es), you simply do more of the test to develop strength. The test is the strengthening exercise.
Achilles (Gastrocnemius & Soleus)
We test the Achilles by performing two tests. The first test is single leg heel raises with the knee straight. We do the second test by repeating the first, except with the knee bent. For both of these tests, you are performing it with your heel off a ledge, like a stair. Testing with the knee straight looks at gastrocnemius strength while testing with the knee bent looks at soleus strength.
If you can complete 20 single leg heel raises without calf cramping or fatigue – and without compensating by leaning forward or using momentum – your Achilles is sufficiently strong. On the other hand, if you can’t, you’ll want to put in some work to strengthen your Achilles, even if you’re asymptomatic. This is one of the most underappreciated muscles of the entire body as it propels your body forward on a daily basis – that’s a lot of weight and a lot of endurance!
Achilles weakness is one of the most common deficits we see in runners, even if shin splints aren’t present. Strengthening this muscle improves performance while preventing injury, so it’s a win-win. It’s also not a difficult exercise to do. Most individuals have steps that are fairly easily accessible so they can knock out a few sets of heel raises without difficulty.
This is the official “shin splints” muscle. It’s the most common weakness we see in those with shin splints. In the clinic, we use our hands to test the concentric strength of this and then we test the eccentric strength with a band. Concentric contractions are when a muscle is shortening while it is contracting and eccentric contractions are when a muscle is lengthening while it is contracting.
For running, the eccentric function of the tibialis posterior is what is most important. This muscle controls the lowering of the arch of your foot as you absorb impact. It needs to be strong enough to control this motion. When it isn’t strong enough, the muscle is constantly overloaded and over-lengthened, which is what causes pain.
Below, we’ve shared a video of what strengthening this muscle looks like. To test to see if you have enough strength, you’ll want to be able to complete 20-30 repetitions with a moderate resistance band. Each of these repetitions should be smooth and controlled. We commonly see “hitches” or abrupt jumps in movement when a runner is bringing their foot back to the starting position. This is eccentric control, which is the important part to work on to eliminate shin splints.
While it’s less common to have issues with this muscle, it is possible. The testing is very similar to how you determine if there are issues with the tibialis posterior. Simply do the exercise with a moderate resistance band for 20-30 reps and ensure you can adequately control the full motion without excessive fatigue. Here’s the video –
When Decreased Mobility Leads to Shin Splints
While it is possible for decreased mobility to lead to shin splints, it is less common than decreased strength. This typically takes on the presentation of having decreased ankle joint mobility.
When the ankle joint is restricted, the middle of the foot (midfoot) is forced to provide more mobility than it should. Increased mobility at the midfoot leads to overstretching of the tibialis posterior and other structures on the bottom of foot. These structures refer pain up into the calf, which is experienced as shin splints.
The best way to target ankle joint mobility is through the mobilization shown below. Unfortunately, this is one that we cannot show you how to accurately assess. In the clinic, we assess it by moving the ankle joint with our hands and grading the mobility that we feel.
Where to Start for Shin Splints
If you aren’t sure where to start, we recommended doing the following –
- Go to a running store or physical therapist to have your shoes assessed for fit and wear
- Evaluate whether or not your mileage has been increasing by more than 10% per week and adjust accordingly
- Start tibialis posterior strengthening
- Start Achilles strengthening
The large majority of the time, these are the steps we take on day one when someone comes in with shin splints. If you aren’t experiencing improvement with these steps or you want to continue to increase your mileage for a race while you heal, we recommend setting up an appointment. We’ve worked with those who do couch to 5Ks all the way to ultra runners. And, Dr. Emily and Dr. Sarah are both runners themselves!