It’s Not About The Tibialis Anterior: High Ankle Sprains In Mountain Ultrarunners

It’s that time of year: 100 Miler Season.

It’s a time of big miles and big vertical, huge climbs and harrowing descents, preparing for whatever the Sierras, San Juans, or San Gabriels have to offer. Most runners methodically log easy mileage and gradually introduce vertical training to prepare for this ‘quad-seasoning’ period considered critical to success in surviving mountain ultras.

But even among the most conservative and best prepared, injury befalls us. And often it is the lower leg. A common complaint amongst my Oregonian Western States training group as they begin to accumulate big vertical is ‘tibialis’–or anterior shin–pain. It has derailed at least two Silver Buckle attempts amongst the group in recent history.

Yet tibialis-anterior pain is typically considered a beginning runner’s injury: something a greenhorn high-school runner feels when they begin flat-track running after a winter of slackerdom. How then, can such an injury befall strong, well-prepared, 100-mile veterans? Maybe because it’s actually not the tibialis, but something else entirely: the ankle joint, itself.

Ankle-Joint Anatomy

All photos courtesy of the author unless otherwise noted.

The ankle is a complex joint that allows for motion–and stability–in multiple planes. It is composed of five critical bones:

• the tibia and fibula, comprising the lower leg
• the talus, which is the go-between, connecting the leg and foot
• the calcaneus, with is the rear connection of the ankle to the foot
• the navicular, which is the forward connection of the ankle to the foot

The primary functional movement of the ankle is dorsiflexion (foot up) and plantarflexion (foot down), but it is the side-to-side motion–pronation and supination–that make fast and fun technical trail running possible.

Perhaps the most overlooked joint in the system is the connection of the tibia and fibula. These lower-leg bones are connected by a thin but thankfully strong film of connective tissue (called a syndesmosis) along the entire length of the two bones, along with a few small but strong ligaments on either end.

However, it is this tibial-fibular joint that, because it is stressed with every single step during normal weight bearing, becomes very difficult to heal when sprained.

Mountain Trail Running: Recipe for Ankle-Joint Dysfunction

Prolonged or repetitive downhill running is a key component to mountain trail races. For many marquee races such as Western States and Hardrock, it IS the race: how to effectively navigate the many relentless ups and downs that often precede runnable sections.

Such physical demands extend beyond the lungs and quads: our connection to the mountain is the foot and ankle, and it can take an enormous beating on steep grades.

Going uphill, the ankle is thrust into maximal dorsiflexion: foot and toes flexed upward. Then, on the downhills, it is reversed: the ankle is plantarflexed, especially if the grade is steep and technical, as the foot molds itself to the downgrade, and plantarflexion allows the muscles of the lower leg to help stabilize the descent. Simple stuff, toes up when you go up, toes down when you go down. But here’s where it gets interesting.

The Wood Splitter: High-Ankle Sprains and Mountain Trail Runners

When running downhill, the ankle is plantarflexed. Yet it is during plantarflexion that the ankle is most vulnerable: the talus has the least amount of articulation with the lower leg and the foot, and must be well-stabilized by the surrounding ankle muscles, as well as cushioned from above by core muscles. This is by design, presumably, so that the joint can make micro-corrections to the demands of the surface: snow or scree, granite or gooey mud.

A plantarflexed ankle, with ground forces going into ankle joint.

The mechanism for high ankle sprains in trail runners: a pronated foot creates a mal-aligned talus, which gets driven upward into the tibial-fibular joint.

It is up to the muscles, therefore, to control the joint over these surfaces, as well as cushion during the descent. But when fatigue and repetitive stress builds, the cushioning system can begin to fail. Moreover, excessive pronation can change the alignment of the talus, and mobility of the ankle can become compromised. Then, the off-kilter talus begins to drive itself into the space between the tibia and fibula.

The high-ankle sprain is rarely on the radar of runners or sports-medical professionals working with runners. It is an injury most often seen in contact sports, as the mechanism is usually forceful compression of the ankle, plus an external rotation twist (e.g. foot goes out when the leg goes in).

But this is the precise mechanism that occurs with repetitive downhill running: a plantarflexed foot opens the joint, and pronation causes a similar rotational stress to the ankle.

But rather than a single forceful event, it occurs with a few thousand foot strikes over thousands of vertical feet of compressive force, with downhill stress driving the talus up into the space between the tibia and fibula. It’s as if the talus is turned into a wood splitter, driving itself in between the tibia and fibula.

Symptoms of a High-Ankle Sprain Versus Tibialis-Anterior Pain

Classic symptoms of a high-ankle sprain include pain on the front of the ankle, at the junction between the lower leg and ankle. Other symptoms include pain with weightbearing, swelling at the ankle, and stiffness in both dorsi- and plantarflexion.

What makes most runners confuse a high-ankle dysfunction with tibialis-anterior pain is that high-ankle sprain symptoms occur in the location of the tibialis-anterior tendon as it courses down the shin to the foot. And since most runners at one point or another have experienced soreness in this area, and often after a big downhill run, most runners assume it is the tibialis anterior that is irritated, and fail to recognize the big picture.

Below are some critical differences between a high-ankle pathology and an irritated tibialis anterior.

Two special tests can help rule in or out a high-ankle sprain.

Squeeze Test
The Squeeze Test involves compressing the bones of the lower leg. Because the connective tissue between the tibia and fibula is continuous, squeezing the top of the leg will stress the bottom. Place a hand on the inside of the upper calf (on the tibia), and the other hand on the outer calf (fibula), and compress. If this reproduces pain at the lower leg and ankle, this is a positive test for a high-ankle sprain. Conversely, this will have no effect on an irritated tibialis-anterior muscle or tendon, which rests on the front of the tibia only.

External Rotation Test
A second test, the External Rotation Test, involves twisting the foot against a rigid lower leg. Typically, a healthcare practitioner will flex to the foot to 90 degrees while you’re sitting, then twist the foot outwardly. This stresses the lower articulation of the tibia and fibula. A runner can do this on his/her own by standing upright on the ankle and gently (very gently!) twisting the leg inward. If this reproduces pain in the lower ankle, this is a positive test. Once again, such a maneuver will have no effect on a tibialis-anterior muscle or tendon.

Generally, these special tests are positive only if the sprain is severe.

Make It to the Start Line! – Treating a High-Ankle Sprain

A common refrain my patients hear from me is, “Muscles, tendons, and bones heal quickly, but dysfunctional joints do not… unless properly treated.”

An irritated tibialis-anterior muscle or tendon should heal quickly and respond well to RICE, as well as soft tissue mobilization to the muscle and tendon, as well as light stretching.

However, because it results in a mild separation of tibia and fibula, high-ankle sprains will resist healing unless properly treated.

Should this injury befall you–especially with only weeks to spare before a major race–I recommend seeking out a knowledgeable medical professional: you will greatly benefit from a skilled manual physical therapist, chiropractor, or osteopathic physician. Aggressive manual therapy to restore the mechanics of the ankle and foot joints is critical to a fast recovery. This could be the difference between a quick return to running, perhaps within days, and losing weeks or even months to this injury.

Should a skilled professional be unavailable, I recommend the following course of treatment.

REST.
Get off the ankle as soon as possible, until the the following steps are taken. Even standing on a high-ankle sprain can seriously hinder healing.

Tape the ankle.
High-ankle sprains respond extremely well to taping. In fact, the best stabilization technique for this injury is taping. To my knowledge, there is no brace on the market that adequately stabilizes the high ankle (without cutting off circulation to the lower leg). For more severe, acute, high-ankle sprains, aggressive stabilization with rigid tape works best. With more mild sprains, a simple kinesiology-tape technique is very effective.

To begin, wash and dry the ankle and foot. Start with about an eight-to-10-inch piece of kinesiology tape, tearing the first inch free. Adhere it in front of the lateral ankle, positioned at a 45-degree angle, upward:

Anchoring the tape with a finger, firmly, with strong tension, pull the tape back and upward, above the heel and the lower Achilles:

Then transfer the tape to your inner hand–maintaining tension–and pull firmly around to the front:

Continue to pull firmly so the tape makes a full revolution around the leg, saving the last inch to be adhered without tension:

This technique adds a crucial posterior glide to the fibula (which is often shifted forward, stiffening the joint), as well as providing a strong compressive force to the distal tibia and fibula. Because it is done in a spiral, circulation is not compromised.

This is a critical technique for the mild–but stiff and painful–high-ankle sprain, as it both provides compressive force to the tib-fib joint, but it also restores normal glide to the ankle joint. This combination allows for speedy healing and a quick return to running for many runners.

Keep it taped around the clock. The joint must be supported until the ligaments have time to heal and tighten. Mild high-ankle sprains may require taping for one to two weeks with minimal running. However, more moderate to severe sprains may require taping for several weeks. Additionally, should you need to continue training high mileage and vertical during this period, taping may be necessary through race day. Most taping techniques will last through one or more showers.

But we’re not done.

Belt Stretching.
The ankle will likely still be stiff. Restoration of dorsiflexion range of motion is critical. Simple wall ankle stretching is usually inadequate. More force is required.

Take any looped belt and secure it low around a heavy, immovable object (such as a bannister or low railing). Place the affected foot and ankle in the loop, with the belt situated on the very top of the foot, at the ankle joint. Then ‘walk it out–at a slight medial-to-lateral ankle (pulling to the outside)–until maximally taut, and lean forward:

The belt stretch, with belt pulling medial-to-lateral.

Keep the heel flat on the floor and slowly bend the knee as far as you can. Oscillate on and off for 30 to 60 seconds. Repeat two to five times, as many as two to three times per day:

The belt stretch, side view. Keep the stretch foot flat, then oscillate a slight knee bend-and-straighten.

Support the foot.
Foot pronation is typically a major contributor to this injury: the arch collapses due to the downhill stress, taking the talus with it. To maintain neutral alignment of the talus, especially in the healing process, consider a shoe orthotic. Off-the-shelf inserts such as Superfeet or similar brands are more than adequate to provide short-term support to the foot. Again, adding this layer to treatment will speed your recovery and possibly allow you to train through this injury while it heals.

Footwear.
Should you be running in minimal or neutral shoes, consider a more stable shoe that includes midfoot stability.

If you can’t walk without limping, rest.
The above techniques should abolish the bulk of your symptoms with normal weightbearing. Should you still have pain with walking that causes limping, rest! Cross train, but any modality you choose should also be pain-free.

Red Flags!
Should you perform these steps and continue to experience pain and swelling seek medical attention if you haven’t already done so. The hallmark indicators for an ankle x-ray include ‘The Four Step Rule:’ being unable to take more than four steps on the affected leg without limping or severe pain, and having palpable pain in the lower three inches of either the medial or lateral ankle. A simple x-ray can rule in or out a fracture. They’re not always that obvious, even to veteran ultrarunners and medical professionals alike!

Big-Picture Tips to Avoid Foot and Ankle Sprains

Once you’re back running, there are a few things to focus on to prevent further ankle and foot issues, especially with high-vertical, technical trail runs.

Stride Efficiency!
Stride mechanics play a huge role in preventing high-ankle sprains and other stresses. For starters, be sure your stride stays compact at all times–flats, ups, but especially downs. A foot that lands more immediately under one’s center of mass is less stressful, especially on downhills, and results in less opportunity for the ankle to go places it doesn’t belong.

Dave Mackey racing Dipsea with his strong run mechanics. Photo: Gary Wang

This is a central concept to efficient run mechanics on all surfaces. Always be mindful of it.

Also, be wary of running too narrow. A narrow stride width can also introduce pronation stress and mal-alignment of the ankle.

Be Stable!
Instantaneous downhill stability and cushioning is critical for a fast, efficient, and pain-free descent. Light plyometrics and single-leg work is helpful, as is the 100-Up exercise described in the last column, the best exercise I’ve come across to improve downhill running stability.

Keep flexible!
Maintain ankle dorsiflexion range of motion: a good marker for ankle health and flexibility. A simple metric may include being able to flex your knee beyond your toes, keeping your heel flat on the floor.

*****

The high-ankle sprain can be a pesky and serious injury, but awareness and aggressive treatment can make the difference between a quick recovery and a DNS–and lost buckle! Good luck and happy, healthy running!

Call for Comments (from Meghan)

Have you ever had a diagnosed high-ankle sprain that didn’t come from an acute incident during a contact sport? Or have you exhibited the symptoms of this injury before? If so, what was the treatment and recovery you went through?