Chronic Ankle Instability: Why Your “Weak Ankles” Keep Holding You Back
If you’ve ever rolled your ankle once, you know how much it sucks. But if you’ve rolled it multiple times—or constantly feel like your ankle could give out any second—you’re probably dealing with something called chronic ankle instability (CAI). And trust me, ignoring it is not the play.
Because as a former basketball player and soccer player and current avid trail runner to train for obstacle course races, I know how to sprain an ankle. It's happened multiple times on both ankles. Fun times.
For runners and hybrid athletes, ankle stability is one of the most underappreciated aspects of performance. Every stride, every jump, every sled push—it all passes through the ankle joint. If it’s not stable? You’re bleeding efficiency, leaking power, and setting yourself up for another frustrating ankle sprain.
Let’s break down what CAI actually is, why it happens, how it wrecks your running, and what you can do to fix it.
What is Chronic Ankle Instability?
Chronic ankle instability is when your ankle repeatedly “gives way” after an initial sprain. Instead of fully healing, the joint stays lax, the surrounding muscles underperform, and your brain starts to trust the joint less and less. Because, spoiler alert, you probably shrugged it off and did not rehab it properly.
Some signs you might have CAI:
Recurrent ankle sprains (especially on the same side)
A constant feeling of wobbliness or weakness in the ankle
Difficulty running on uneven terrain
Avoiding cutting, pivoting, or explosive movements out of fear
How Does It Happen?
The most common culprit? A lateral ankle sprain—when your foot rolls inward and overstretches or tears the ligaments on the outside of your ankle (like the ATFL and CFL). It's the most commonly sprained ligament in the body.
Here’s the problem: after that initial sprain, a lot of athletes don’t rehab it properly. Maybe you rested a few days, iced it, then jumped back into training. Sure, the swelling went down, but your ankle stability never fully returned. That's a problem, and something that most individuals are not even aware of.
The result:
Ligament laxity → the passive support structures stay stretched out.
Neuromuscular deficits → the small stabilizer muscles (peroneals, tibialis posterior) don’t react as quickly.
Proprioceptive loss → your brain is slower to sense where your ankle is in space, so you’re more likely to misstep again. This goes first, so it needs to be the first restored.
This is the perfect storm for recurrent sprains—and eventually, chronic instability.
How Chronic Ankle Instability Wrecks Your Running
Running is basically a single-leg sport. Every stride is a controlled leap onto one leg, and your ankle is the first point of contact with the ground. If that joint is unstable, a few bad things happen:
Loss of Power – Your calf, Achilles, and foot can’t transfer force efficiently. That means weaker push-offs and slower paces.
Compensation Up the Chain – Your knee, hip, and even your low back end up doing extra stabilization work. Hello, overuse injuries where you may not expect them.
Reduced Dorsiflexion – Limited dorsiflexion (the ability to bring your knee over your toes) alters your stride mechanics. You’ll overstride, heel strike harder, and lose running economy, because your ankle can't move all the way through it's available motion.
Fear of Movement – This one’s underrated. If you’re subconsciously worried about rolling your ankle, you won’t run relaxed or aggressively. That’s free speed left on the table.
Strategies to Fix Chronic Ankle Instability
Good news: you’re not doomed to “weak ankles” forever. Research consistently shows that targeted exercise, proprioception drills, and mobility work can dramatically improve ankle function. Here’s how to tackle it:
1. Restore Dorsiflexion Mobility
A stiff ankle is just as bad as a loose one. Limited dorsiflexion is strongly linked to both ankle sprains and poor running mechanics (Bennell et al., 1998). This needs to happen fast and early.
Try these:
Half-Kneeling Dorsiflexion Mobilizations: Place your foot flat, drive your knee forward over your toes while keeping your heel down.
Banded Ankle Distraction: Use a resistance band around your ankle joint to improve joint glide as you mobilize.
Weighted Ankle Stretch: Place a kettlebell on top of your knee while in a lunge to load into dorsiflexion.
Aim for daily mobility work, especially pre-run. Key word is daily.
2. Train Proprioception and Balance
Your brain needs to trust your ankle again. Proprioceptive training has been shown to significantly reduce recurrent ankle sprains (McKeon & Mattacola, 2008).
Try these:
Single-Leg Balance with Perturbations: Stand on one foot while a partner or band challenges your balance. You can also add head turns for a visual distraction, which will be more for proprioception.
BOSU or Foam Pad Balance: Add an unstable surface to mimic real-world conditions. This WON'T work for proprioception, but will for balance and ankle stability. Both good for CAI.
Single-Leg Hops: Hop in place, then forward/backward and side-to-side.
3. Strengthen the Ankle Stabilizers
Strong muscles = more active stability to compensate for ligament laxity.
Peroneal Strength: Banded eversion (pulling foot outward against resistance).
Tibialis Posterior: Calf raises with a ball squeezed between heels.
Calves & Soleus: Straight-leg and bent-knee calf raises for push-off strength.
Fun fact: A 2021 study in Sports Medicine found that calf and peroneal strengthening not only improves stability but also restores confidence in athletes with CAI. Yay.
4. Progress to Dynamic Stability
Once you’ve built strength and mobility, take it to real-world speed.
Bounding Drills (forward and lateral and all other directions)
Agility Ladder Work (not for "agility", but for foot contacts)
Trail Running or Grass Work (start small)
The goal is to make your ankle resilient under load, speed, and unpredictability—exactly what happens in races.
The Takeaway
Chronic ankle instability isn’t just about your ankle—it’s about your performance. If you’re rolling your ankle every season, avoiding uneven terrain, or losing power in your stride, you’re not reaching your potential as a runner or hybrid athlete.
Fixing it isn’t complicated—but it does require consistency. Work on dorsiflexion, strengthen the stabilizers, train your balance, and slowly reintroduce dynamic challenges.
Your ankles are the foundation. Build them strong, and you’ll run faster, recover better, and race without the constant fear of rolling them… again. If that sounds like you, then schedule your free call here to discuss your options and get you back on the road to recovery.
