Why do I keep getting shin splints when running? Three causes that you can fix.

Shin splints on day 3…with 50 days to go.

In her quest to race the Appalachian Trail, ultra-distance runner Liz “Mercury” Anjos took a hard-and-fast approach right from the start. “I know 69 miles [the first day] sounds crazy, but I promise it was part of the strategy. …why not put in some big miles while I’m fresh, right off the bat?” Anjos said.

While she accomplished her goal, achieving the fastest time ever by a woman on the northbound route, a nasty bout of shin splints nearly derailed her race by day three. A quick pivot in strategy to lower daily mileage goals enabled her to continue racing and finish the 2,190-mile course without shin pain. 

Anjos’ experience highlights a common cause of shin splints in runners: too many miles, too early on. When the volume of work exceeds the legs’ ability to adapt to the new challenge, pain shows up. Although Anjos’s base fitness and quick strategy change saved her on the Trail, I think there was a hefty dose of luck there as well. Few runners I’ve known can outrun a bad case of shin splints. 

Mileage volume is just one of three key factors that can leave even the most experienced runner clutching their legs as they hobble off the trail in pain. In this article, we’ll cover three significant causes of shin splints that you can fix; no specialized training is required.

1. Volume

Given enough time and the right environment, the body will adapt to increased training stress. This includes the bones, muscles, and tendons of the shin and ankle. A proper balance of stressors is key to improving capacity while preventing injury.

Too much too soon, though, can overload your legs. Your shins – the force conductor between your foot and thigh muscles – usually bear the brunt of training-related insults. While there is no one best method of increasing mileage, the well-established “10 Percent Rule” still works quite well for most runners.  

Using the Rule, take your weekly mileage goal, calculate what 10% of that number is, then increase your mileage each week by that amount (or less). For example, if you currently run 15 miles per week, increase your total weekly mileage by no more than 1.5 miles. If you run 3 miles per week – such as a mile or two as a warm-up before lifting workouts – that means you can only increase your total mileage by 0.3 miles (seriously!). 

Unfortunately, the flip side of too few miles can also cause shin splints. Run (or hop, or jump) too little, and you’ll likely end up with Weekend Warrior Syndrome – cramming a week’s worth of impact forces into a single session based on your schedule, not your legs’ current ability.

Splitting up your weekly miles into 3 runs per week may reduce your risk of impact-related injuries such as shin splints. For example, suppose you did a medium tempo run on Monday (e.g., 30 minutes), a set of intervals (like quarter mile repeats) on Wednesday, and a longer easy run on the weekend. This schedule would allow you to train at various speeds and impact loads to help your shins adapt. 

What if you can’t get 3 runs in during the week? Schedule in some other type of impact exercise. For example, you could do a quick 15-minute workout alternating jump roping intervals with push-ups, pull-ups, or core work. This mini-session will ensure your shins get the regular impact exposure they need to stay strong. 

2. Cadence

Cadence is the total number of steps taken each minute of running. While everybody is different, efficient runners tend to run at a tempo of around 180 steps per minute (3 steps per second). If your steps per minute are below 170, a low cadence is probably causing some component of your shin trouble. The fewer steps you take, the longer your foot is in contact with the ground and absorbing impact forces.

In my experience, a cadence that falls in the 155-165 range is common amongst tactical athletes who develop shin splints. This cadence is often adopted by the group on formation runs. Running in boots instead of lightweight running shoes further compounds the problem. 

In runners who develop shin or knee pain, increasing cadence as little as 5% (usually 5-10 steps per minute) has been shown to relieve pain and improve running efficiency. It’s easiest to adjust cadence as a byproduct of better running mechanics, e.g., lighter shoes, improved strength, or improved running technique. However, suppose time or circumstances dictate that you must run a certain way and in specific footwear. In that case, you can consciously increase your cadence until other training methods are more feasible.

To consciously increase cadence, practice by running in place or jumping rope to a metronome music device set to 170 beats per minute or more. Or, practice running to the beat with one of the songs below. The idea is to “step it out,” not“stride it out,’ particularly when you start to get tired.

3. Ankle Mobility

When you run, your ankles work like pistons, transferring forces back and forth from your legs and the ground. When an ankle doesn’t move as it should, its ability to absorb shock and produce power is compromised. As a result, other structures up the chain (like shins) experience more stress than they should. 

Your ankles should bend enough that, in a kneeling position, your knee tracks forward beyond the tips of your toes while you keep your heel planted firmly to the floor. This motion is called ankle dorsiflexion. For most people, the ankle should dorsiflex enough that the knee advances beyond the toes by four inches or about the width of one’s palm on both legs.

To measure your own ankle motion, review the steps in the article, A Fix for Stiff Ankles – Your Knees Will Thank You!

Flexible ankles may not solve all of your shin problems, but they will alleviate unnecessary stresses that contribute to shin splints. Increased ankle mobility can also have powerful effects on reducing knee, hip, and low back pain. 

But I still have shin splints…what now?  

If you correct volume, cadence, and ankle mobility but still have shin splints, it’s now time to get a professional assessment. This can identify hidden causes, such as muscle imbalances, scar tissue, or bony stress fractures. As pain is present, you’ll need a sports medicine pro to tease out the root cause. A running coach or running shoe provider would not be the best choice at this stage because any deviation one might see in your running pattern is likely to result from pain or injury, not be the cause of it. 

If you don’t have access to a sports physical therapist or athletic trainer who regularly works with runners, ask for recommendations from local high schools or running clubs. These organizations work with hundreds of runners yearly and often have trusted medical support staff in their networks.

Summary 

Shin splints can be incredibly painful and discouraging for both novice and advanced level runners. While they can be tricky to eliminate, it absolutely can be done. The vast majority of runners just haven’t taken enough off the table worth investigating or have devoted too little time spent testing new strategies. 

Take a look at your training volume, cadence, and ankle mobility. Apply some corrective work and see if that reduces your shin pain. If not, seek out a professional assessment to help you stay up and running!


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