Achilles Tendinopathy in Runners: Why Your Heel Pain Isn’t Just “Tight Calves”
If you’re a runner dealing with stiffness or pain in the back of your ankle, especially first thing in the morning or at the start of a run, chances are you’ve been told some version of:
“Your calves are just tight.”
“You need to stretch more.”
“Take a little time off and it’ll calm down.”
But if that actually worked, you probably wouldn’t be reading this. Following this advice leads to an injury cycle that is incredibly common and it’s exactly why Achilles tendinopathy is one of the most frustrating injuries we treat at our Atlanta-based running physical therapy clinic.
The problem usually isn’t effort or discipline. It’s that runners are often given advice that doesn’t actually address why the tendon hurts in the first place. The good news is that once you understand why it’s happening, the path forward becomes much clearer.
What Is Achilles Tendinopathy?
Your Achilles tendon connects your calf muscles (gastrocnemius and soleus) to your heel bone. Every step you take while running loads this tendon often with forces 6–8 times your body weight.
Achilles tendinopathy develops when that tendon is exposed to more load than it can tolerate over time. This is not an inflammation problem. This is not a one-run injury. It’s a load tolerance problem. Check out this blog to learn more about tendinopathy in runners.
In simple terms: the tendon isn’t “damaged”; it’s underprepared for the demands you’re placing on it.
Why Achilles Tendinopathy Is So Common in Runners
Most runners don’t develop Achilles pain because they’re doing something “wrong.” It usually shows up when training demands increase faster than the tendon can adapt. There are certain patterns that we see in the clinic and the most common triggers we see in Atlanta runners include:
1. Training Changes
Increasing weekly mileage
Adding speed work or track workouts
Introducing hill repeats
Running more aggressively downhill
Gradual changes in training stimuli aren’t behind this injury. It’s when these changes happen too much, too soon where runners get in trouble. Even small changes can matter if several happen at once.
2. Shoe Changes
Switching to:
Lower-drop shoes
Minimalist shoes
Carbon-plated racing shoes
can significantly increase Achilles load, especially if the transition is rushed. Having a running shoe rotation is okay and even what we generally recommend to our runners but runners want to be careful when they are changing up their shoes.
3. Calf Strength Deficits
This might surprise you, but Achilles tendinopathy is often linked to reduced calf strength, not tightness. Most runners are convinced their tight calves are the problem and are reluctant when I recommend they focus on calf strengthening. “But won’t that just make the calf tighter?” they ask. A tight muscle is a weak muscle so the key is strengthen, strengthen, strengthen.
When the calves can’t handle load efficiently, the tendon absorbs the stress instead. Over time, this can lead to overload of the tendon and pain to develop.
4. Running Mechanics
Overstriding, low cadence or inefficient push-off mechanics can all increase Achilles strain, especially at faster paces. Gait abnormalities in the foot/ankle complex upon landing can also contribute to Achilles tendinopathy in runners.
What Achilles Tendinopathy Feels Like
Most runners report:
Stiffness first thing in the morning
Pain at the start of a run that “warms up”
Soreness the day after hard workouts
Tenderness either mid-tendon or closer to the heel
That “it loosens up as I run” feeling is a classic sign of tendon involvement.
What Actually Helps Achilles Tendinopathy in Runners
Stretching your calves may feel good temporarily, but Achilles tendinopathy is rarely caused by a lack of flexibility. And rest alone often leads to:
Short-term symptom relief
Followed by pain returning as soon as training resumes
Without improving the tendon’s ability to handle load, the cycle continues. As running specialized physical therapists, here’s what we recommend to the runners the come into our clinic:
1. Modify Training (Not Eliminate It)
Most runners don’t need to stop running completely. Instead, we often:
Reduce speed work
Limit hills temporarily
Space out harder sessions
The goal is to keep the tendon active within tolerable limits.
2. Progressive Calf Strength Loading
This is the cornerstone of Achilles rehab.
A structured program typically includes:
Isometric calf loading early on
Slow, heavy calf raises
Gradual reintroduction of plyometric demands
Random exercises won’t cut it, progression matters.
3. Address Foot, Ankle and Hip Strength
Weakness elsewhere in the body can overload the Achilles tendon so runners will want to focus on improving:
Foot stability
Ankle control
Hip strength
Core strength
All of these will help distribute forces more efficiently and keep the Achilles tendon happy.
4. Optimize Running Mechanics
The goal is not to change how you run. We want to optimize it. That’s where our 3D running analysis comes into play. Small changes, like a slight cadence increase, can meaningfully reduce tendon stress without changing how running feels.
When to See a Running Physical Therapist in Atlanta
If your Achilles pain:
Has lasted more than 2–3 weeks
Keeps flaring every training cycle
Limits hills or speed work
A running-specific PT evaluation can identify why the tendon isn’t tolerating load and how to rebuild that capacity.
If you’re a runner in the Atlanta area, we can help! Book a free consultation call with us and let’s get started on the path to pain free running.
