Achilles Tendinopathy in Runners: 4 Rules That Actually Help

TL;DR

Why runners get Achilles pain

People start running for different reasons. Weight loss, better heart health, stress relief, or simply wanting a routine that feels productive. But the longer you run, the more likely you are to run into something that slows you down.

One of the most common warning signs is feeling pain or stiffness near the heel. That can be an early sign of Achilles tendinopathy, which is irritation and breakdown in the Achilles tendon from training stress adding up faster than your body can adapt.

The Achilles tendon connects your calf muscles to your heel. It helps store and release energy every time you land and push off. It is not one simple rope. It is made up of three subtendons that twist together in a spiral.

Why this study is worth paying attention to

A lot of injury advice is based on reactive research. That means researchers start with injured runners and look backward to guess what caused the problem.

This study was different. It was prospective. Participants were tested at baseline, then followed for a full year to track who developed Achilles tendinopathy. ¹

• Participants came from the Healthy Aging in Industrial Environment Program 4 (4HAIE). ¹
• Researchers screened a large pool and analyzed 911 participants, which helps reduce noise and improves reliability. ¹
• Training volume was based on wearable data, with participants wearing Fitbit Charge 3 or 4 devices during the year. ¹

The 4 rules to protect your Achilles

Rule 1: Train to recover

Your Achilles does not get stronger during the run. It gets stronger during the time between runs. Running creates stress in the tendon, and your body responds by rebuilding collagen. If you keep stacking stress without enough recovery time, the tendon never fully catches up.

Think about a road crew fixing potholes with wet cement. If cars drive over it immediately, the cement stays soft, the surface gets rutted, and the repair does not hold. It is the same with your Achilles. If you load it again before it has had time to rebuild, irritation grows.

A good rule of thumb is allowing about 1.5 to 3 days for ample recovery after heavier loading, and many runners need more recovery time as they get older.

Rule 2: Stop obsessing over foot strike and foot position

A lot of runners get told their heel strike is the problem and midfoot striking is the solution. This study did not support that. Footfall pattern was not the deciding factor for who developed Achilles tendinopathy. ¹

Your Achilles is a three-part spiral. If you force a big change in foot strike or foot position before your body is ready, you can change how tension spreads across those subtendons. That can irritate a different part of the tendon, or shift stress into tissues that are not prepared.

Instead of forcing form changes during your runs, run in a way that feels natural. If you want to improve mechanics, earn it through strength training, mobility work, and controlled drills.

Rule 3: Respect weekly mileage (and avoid big jumps)

This study put a number on how risky it is to increase weekly volume too quickly. For every 12.5 km per week increase in running volume, which is about 7 to 8 miles, the odds of developing Achilles tendinopathy increased by 67%. ¹

Big mileage jumps are not a small change. They are a big step up in total stress. And if you keep stacking those jumps, the risk rises fast.

Rule 4: Build the brakes with resistance training

Running is not just moving forward. It is also your body catching you every time you land. If your lower leg cannot control that landing, the Achilles ends up taking more of the stress.

Runners who were better at controlling the ankle under load had a lower risk of Achilles tendinopathy. The paper describes this as stronger control in two directions: ankle inversion and ankle external rotation. ¹

You do not need to memorize those terms. The takeaway is that you want ankles that stay strong and controlled as you land and push off, not ankles that collapse or twist when you get tired.

Two training tools that can help tendon strength and performance, even though they are not “prescribed” by the study, are:

• Loaded isometrics, which are strength holds under load that build tendon tolerance
• Plyometrics, which are controlled jumping and explosive drills that train the tendon like a spring

The goal is not to force a new running style during your runs. The goal is to build capacity so your body can handle running mechanics safely.

Bottom line

If you want to protect your Achilles, stop chasing perfect form and start managing the big rocks:

1. Train to recover
2. Stop obsessing over foot strike and foot position
3. Respect weekly mileage
4. Build the brakes with resistance training

Want a plan that builds your mileage safely?

If you want help building a running plan that matches your goals and protects you from common injury risks, we can help.

• For custom coaching and a personalized plan, email info@maxwellnutrition.com and one of our coaches will reach out.
• If you want to get started right away, download the MaxWell Nutrition App and start with Strong and Lean to build the strength foundation that supports healthy running.