By: Sean Rimmer, Physical Therapist & Run Performance Coach
at Run Potential Rehab & Performance in Colorado Springs, CO.
As trail runners it’s only a matter of time until a running-related injury (RRI) occurs as that’s the unfortunate reality of our sport. Up to 80% of trail runners will deal with some sort of minor to severe RRI per year. In trail running, a RRI can occur due to a traumatic event or from repetitive microtrauma. A RRI is defined as an injury that causes a restriction or stoppage of running for at least 7 days or 3 consecutive scheduled training sessions, or that requires a runner to consult a health professional. One of the most common traumatic RRIs I see in trail runners is the lateral ankle sprain (LAS). In this article, I will highlight the importance of understanding the LAS injury itself, healing, and considerations to return to running with confidence. In this article, I will discuss the soft tissues in LAS, the considerations on the causation of LAS, and important management considerations for recovery.
Lateral Ankle Sprains (LAS)
LAS are much more common in trail runners due to the less predictable and variable terrain. LAS most often occur when our foot excessively supinates (plantar flexes and inverts) just after initial contact. This typically occurs when our foot contacts on a rock, root, or an unpredictable surface where our body isn’t able to compensate in a timely manner. This type of event then over-stresses the lateral ligaments between our shin bones (tibia and fibula) and rear-foot (talus and calcaneus). The most common ligament that is sprained during a LAS is the anterior talofibular ligament (ATFL), and second most common is the calcaneofibular ligament (CFL) (The ligaments are named from the bony attachments they share). Both of these ligaments are stressed during excessive inversion and in degrees of plantar flexion, they are sprained once their capacity is exceeded in which micro to macro tears occur in the ligament.
A sprain differs from a strain (contractile tissue), where a sprain occurs in a ligament when it elongates and potentially tears. Ligament sprains are graded based on the severity from grades ranging 1-3: A grade 1 sprain is when the tissue is elongated with micro-tears, a grade 2 sprain is when the tissue involves a partial tear, and a grade 3 sprain involves a complete tear/rupture. The higher the grade, the longer the recovery time and higher risk of potential complications in the future. The healing time for grade 1 LAS is typically 2-3 weeks, grade 2 is typically 4-6 weeks, and grade 3 is around 12+ weeks. When I state “healing time” that’s more of a definition of the ligament tissue itself healing, but what’s also equally important in recovering is restoring rear-foot/ankle range of motion (ROM), strength, motor control at the foot/ankle, and confidence to return to running.
Unfortunately, if you’ve dealt with a LAS at least one time, the likelihood of you dealing with another, or multiple in the future, skyrockets. This is often because the aforementioned ROM, strength, and movement control were not fully restored during the recovery process. This leaves a fault in your movement quality at the foot/ankle which increases the risk of chronic ankle instability (CAI). In the next section, I will highlight the importance and specifics of each factor related to recovery: ROM, strength, motor control, and confidence to return to running.
Foot & Ankle ROM Considerations
In the early phases of a LAS, ranging from days to the first 2 weeks, the primary focus is to reduce any local swelling, restore weight-bearing function as tolerated, and active ROM as tolerated through all planes of motion in progressing from open chain to closed chain weight bearing ROM. Once swelling is down and walking is tolerable, the areas of ROM that are imperative to restore are ankle dorsiflexion and rear-foot eversion. The pattern I often see in both acute LAS and in individuals with CAI is that their rear-foot is limited in eversion. When your foot and ankle are limited in dorsiflexion and eversion, this tends to leave your foot in a slightly supinated position (plantar flexed and inverted). This is a potential problem, as this reduces the foot’s natural loading ability, and creates an increased risk for another LAS. Now, there are a multitude of exercises and mobilizations that can improve ankle dorsiflexion and rear-foot eversion, but in my clinical practice, here are my top 3 recommendations that I have found to be successful.
1. Active ankle inversion/eversion inverted “U” exercise:
This exercise includes slow and controlled foot/ankle movement starting in some ankle dorsiflexion and inversion, moving up into ankle plantar flexion and inversion, then to ankle plantar flexion and eversion, and then ankle dorsiflexion and eversion. Then you reverse. The movement ends up looking like an inverted-U. This can be done with both feet or one, from the ground or on a slant-board, and with external loading all as progressions or regressions to meet the individual.
2. Forward step downs:
This exercise incorporates closed chain active loading into ankle dorsiflexion and eversion by having the involved foot standing on the step while the other leg steps down to tap the ground, then returns back to the start. This can be challenged based on the height of the step, the rate of the step down, external loading, as well as how far the non-stance leg reaches forward.
3. Manual rear-foot eversion mobilization in sitting:
This can be done by someone else or as a self-mobilization if your hips have the mobility to access the position. This mobilization improves the rear-foot eversion by placing an inward pressure or glide to the rear-foot just below the lateral malleoli (fibula), and it helps to have your knee elevated from your ankle via a foam roller or your other leg to enhance rear-foot eversion motion. This is best held for ~2 minutes.
If all of these motions are restored and controlled under active load, we can further build specific strength and movement control to enhance recovery and reduce the risk of CAI.
Foot and Ankle Strength Considerations
Improving strength around the foot and ankle is also highly important to improve tissue resiliency; though a specific area to improve strength post LAS would be via the peroneal muscles. The peroneal or fibularis muscles include the peroneus brevis and longus. Both muscles originate in the lateral lower leg and long tendons that wrap behind our lateral malleoli attaching to our lateral midfoot (peroneus brevis) and the medial plantar surface of our foot (peroneus longus).
These muscles help transition the foot from a rear-foot inversion to eversion after initial contact, and they can also act as a defense against LAS if they are strong and able to contract in a timely manner. To improve the functional strength of this muscle group, we need to work the muscle group in plantar flexion and eversion as that’s it’s primary function. My favorite strengthening exercise variation is as follows:
1. Single leg heel raise from a laterally down-sloped slant board as an isotonic (movement) and isometric (hold): This can be progressed with more weight, longer hold times, or you can start from the level ground with support from your arms. The lateral down slope increases our foot’s ability to invert, therefore, we need to activate the peroneal muscles to help evert our rear-foot while we rise up or hold in some degree of plantar flexion. If these muscles are weak or lacking control, we are at a higher risk of a LAS returning.
Motor/Movement Control + Return to Run Confidence
Motor control is when our internal software from our nervous system relay signals to our working muscles to coordinate the timing of our muscles contracting. If timing and coordination are impaired in our lower extremity, specifically at the foot/ankle, then this can heighten the risk of our ankle “rolling” again. We ultimately need our foot and ankle to be able to load and produce force under control at a minimum to run, but also handle uphill/downhill loads and trails with varying and unpredictable terrain. In order to return to running with confidence, it’s important to be able to handle single leg dynamic loads in standing as well as plyometric in nature (think hopping based movements). Again, you can be creative with motor control exercises to return to running and there are a multitude of options for progressions. But here are a few of my favorite exercises to progress in a later stage LAS:
1. Multi-directional single leg pogo hops - The two variations I recommend are in a box and reverse box pattern as well as a star and reverse star pattern. The box pattern includes single leg hopping forward, lateral, back, then lateral to form a box, and a reverse box pattern would be the opposite way. The star pattern includes single leg hopping in a star pattern, which adds in a diagonal vector of movement.
2. Single leg balance with arm swing - This exercise involves standing on a single leg with the other hip flexed in a march position, while the individual then performs faster arm swings in standing. This challenges the dynamic stability of the foot in the ankle while the upper trunk/arms are moving. This can be progressed by performing on a slant board tilting downward laterally, or with lighter weights in each arm.
Once you can tolerate single leg loading under control with confidence in a controlled setting, we can return to running with a focus on gradually progressing the challenges of terrain, speed, and duration of running. Below you will see a general continuum of factors to be progressed as confidence improves at the foot/ankle.
Run/walk → Continuous running
Flat→ Steeper up/down hill trails
Smooth wider trails →Narrow technical trails
Slower→Faster running
I would typically recommend progressing one challenging variable at a time, rather than multiple at once, to really ensure the individual is gaining confidence and feels ready. Because the last thing you’d want is another LAS to occur and which sets you back again.
Closing Thoughts
As a trail runner, there’s a high potential you may deal with a varying degree of LAS from minor to severe (but hopefully not!). My hope is that you now have some ideas and strategies to consider implementing when managing your own LAS. Ensure to focus on restoring ROM, strength, movement/motor control, and confidence to return to running.