Achilles Pain in Runners - What it means, and how to get back on track
Two years ago, while training for the Escape from Alcatraz Triathlon, I found myself dealing with Achilles pain. Alcatraz was a bucket-list race for me, the trip was booked, and there was no way I was going to miss it. But as my training ramped up, my Achilles had other plans. Running became painful, and I knew I had to make some adjustments fast if I wanted to get to that start line.
I shifted my focus to cycling and swimming, and I cut my run volume down to just a couple of short run/walk intervals per week. Meanwhile, I committed to my Achilles rehab, focusing on strengthening and loading my tendon properly. Looking back, I realized why it likely happened in the first place. Calf strength was something had to work on, and I probably didn’t have the strength to withstand the amount of hill training I was doing to prepare for San Francisco’s terrain.
Despite the setback, I made it to race day, and Escape from Alcatraz was the coolest race I have ever done! My swim and bike were strong, and although my run was not my best due to limited running training, I made it through pain-free, soaking in the scenery every step of the way. One day, I’ll go back and smash that run! That experience demonstrates what I know as a physical therapist: Achilles tendinopathy doesn’t just go away with rest (or by ignoring it). You have to put in the work to fix it.
What is Achilles Tendinopathy?
Achilles tendinopathy is a structural change, not an inflammatory condition, of the Achilles tendon. A healthy tendon is made primarily of Type I collagen, which is strong and well-organized to handle tensile loads. However, in tendinopathy, there is an increase in weaker, disorganized Type III collagen, which makes the tendon less resilient and more prone to injury. It also can develop neovascularization (the growth of small blood vessels and nerves into the tendon), which can contribute to pain and sensitivity. Because the issue lies in tissue structure, not inflammation, treatments like ice or anti-inflammatories offer only temporary relief. Long-term improvement depends on progressive loading to stimulate tendon remodeling, in order to promote strong collagen formation, reduce unnecessary vessel growth, restore function, and alleviate pain.
Why Does Achilles Tendinopathy Happen?
Achilles tendinopathy develops when the load placed on the tendon exceeds what it can handle. Common causes include:
Training errors (i.e. too much too soon, not enough recovery, etc.)
Sudden changes in running terrain (i.e. incorporating a lot of hill training)
Calf weakness (shifts excessive stress onto the Achilles tendon).
Ankle or foot mobility deficits (tendon compensates for the lack of movement elsewhere)
Poor stability (weakness at hips/ankles/feet creating imbalances that lead to excess strain on the tendon)
How Do We Fix It?
The key to Achilles rehab is relative rest. This doesn’t mean stopping all activity, but rather modifying your training it so that you’re not continuing to aggravate the tendon. For runners, this usually means cutting back on mileage and intensity. In some cases, taking a short break from running is necessary. At the same time, it is important to start strengthening the tendon with progressive loading exercises to rebuild its capacity to handle stress.
When dealing with a highly irritable Achilles, we often start with isometric calf raises, which can have an analgesic effect, helping to reduce the pain while strengthening the tendon. Then we may progress to eccentric and/or concentric movements (active heel raises, erc.), and later, explosive exercises like plyometrics to restore power.
This is not a quick fix. A proper rehab program takes time and must be progressed as you get stronger. It’s important to note that tendon remodeling continues well after symptoms fade. It can take over a year for the tendon to fully remodel at the tissue level, even though the pain may resolve in a few months. That’s why it’s essential to continue your loading program well after the pain is gone to reduce the risk of recurrence and ensure the tendon regains its full capacity.
Addressing the Root Cause
One of the biggest mistakes runners make is to simply rest until the pain goes away, then jump back into training as if nothing happened. The problem with this approach is that rest alone doesn’t fix the underlying issue – it only reduces symptoms temporarily. If you don’t address the root cause, the pain will likely return as soon as you start running again.
That’s why it’s crucial to identify what contributed to the injury in the first place. If calf weakness was the issue, strength training needs to be a long-term part of your routine. If ankle mobility is limited, that needs to be improved. If training errors were to blame, your training plan needs to be adjusted to avoid overloading the tendon again.
The Takeaway: You Can Keep Moving!
One of the most important things to understand about Achilles tendinopathy is that you don’t necessarily have to stop running altogether. Many runners can continue training at a reduced volume while working on their rehab. The key is to listen to your body, gradually increase load, and avoid pushing through significant pain.
If you’re dealing with Achilles pain, don’t ignore it or try to “run through it.” Get assessed, find out what’s contributing to the issue, and start strengthening your tendon properly. With the right approach, you can get back to doing what you love—without pain slowing you down.