Achilles pain responds well to the right plan: eccentric calf work, measured progression, strong calves, good shoes, and compression for support. If pain sticks or your daily movement is limited, bring in a physio before it settles in.
Our compression socks for Achilles issues give targeted support during sport and recovery. More on how STOX compression is built.
Morning stiffness at the back of your ankle. A dull ache that starts mid-run and refuses to let go. A tender, thickened spot just above your heel. These are the calling cards of an Achilles issue, and they show up in runners, walkers, footballers, and people who've never considered themselves athletes.
The Achilles is the strongest tendon in your body. Also one of the most frequently injured. This guide covers where the pain comes from, how to tell it apart from related problems, what helps acutely and long-term, and how to keep it from coming back.
What the Achilles does
The Achilles connects your calf muscles (gastrocnemius and soleus) to your heel bone. Every time you push off (walking, running, jumping, standing up) it takes the load. When you run, it absorbs impacts of up to eight times your bodyweight. That works for years. Then the balance between load and capacity tips, and you notice.
The different problems that get lumped together
Most people say "Achilles tendonitis". Medically, the picture is more specific:
- Achilles tendinopathy. The most common version. Not classic inflammation but tissue degeneration from repeated overload. Matters because ice and anti-inflammatories do less than people assume.
- Achilles tendonitis. True acute inflammation, usually after a sudden load spike.
- Achilles bursitis. The fluid sac between tendon and heel bone gets irritated.
- Paratendonitis. The tissue around the tendon, not the tendon itself.
- (Partial) rupture. Acute, severe, often surgical.
This guide uses "Achilles tendon pain" as the catch-all and focuses on tendinopathy, the form most people are dealing with.
Symptoms
- Stiffness at the back of the ankle, worst in the first steps of the day
- A dull ache 2 to 6 cm above the heel bone
- Pain that warms up during activity, then comes back worse once you cool down
- A visible or palpable thickening on the tendon
- Pain lifting your toes against resistance or rising onto the balls of your feet
- In severe cases: swelling, warmth or a distinct lump
Red flag: a sudden sharp pain that feels like a kick to the back of the leg, often with a snap and immediate loss of function. That's a possible rupture. Go to urgent care.
What causes it
Almost always an overuse problem, triggered by one or more of the following.
Training
- Ramping volume or pace up too fast
- Sudden uptick in hills or stairs
- Switching from cushioned shoes to minimalist ones
- Returning to sports without a proper build-up
Biomechanics
- Stiff or weak calves
- Overpronation or flat feet
- Limited ankle mobility
- Strength or length imbalances between legs
Other
- Ill-fitting or worn-out footwear
- Age: tendons lose elasticity over time, especially after 40
- Bodyweight: every kilo multiplies the load
- Certain antibiotics (fluoroquinolones) are linked to tendon issues
What to do
In the acute phase
- Relative rest. Drop the painful stuff. Keep gentle pain-free movement going.
- Ice for sharp pain or visible swelling, 15 minutes at a time
- Swap load-bearing sport for cycling, swimming or the cross-trainer for a while
- Check your shoes. If they're worn, replace them.
For tendinopathy and chronic complaints
The workhorse here is eccentric calf training, the Alfredson protocol. Stand on a step, rise on both feet, then lower slowly on one so your heel drops below the step edge. Three sets of 15, twice a day, for 12 weeks. Research shows meaningful improvement in 70 to 90% of patients, chronic cases included.
Alongside it: gentle calf stretching, physiotherapy if pain persists, and shockwave therapy for stubborn cases.
Compression and support
Compression helps by improving circulation, reducing swelling, and supporting the calf-to-Achilles unit during activity and recovery. Our Achilles tendon socks are built with extra cushioning and graduated compression around the tendon, so the load during sport and everyday activity sits lighter on it. Not a substitute for rehab work. A solid support layer on top of it.
Prevention
1. Build load gradually
The 10% rule: no more than 10% more training volume per week. Same rule for hills, speed, and new shoes. More on preventing running injuries here.
2. Strong calves, mobile ankles
Calf raises three times a week. Both legs, then progressing to single-leg. Add gentle stretching for the gastrocnemius and soleus (the latter with the knee bent).
3. Warm up, cool down
Five to ten minutes of easy movement before anything intense. Cool down with light pace and gentle stretching.
4. Get the shoes right
Replace running shoes every 600 to 1000 km. Match cushioning and drop to your natural stride. Recurring issues are a cue for a gait analysis or podiatrist visit.
5. Mix up the surface
Hard tarmac all the time is brutal on the Achilles. Rotate in grass, forest trails, and rubberized tracks.
6. Compression during longer sessions
For long walks, training sessions and the build-back phase, Achilles tendon socks take the edge off the load and keep circulation steady.
When to see a physio or doctor
- Pain lingers past 2 to 3 weeks despite rest and tweaks
- Pain at night or pain that wakes you
- Swelling, warmth, or redness
- A clear thickening or lump
- You can't walk normally
- You suspect a rupture. That's urgent care, not a waiting-room case
A sports physio will diagnose, build a targeted plan, and use manual techniques or shockwave where needed. The earlier the intervention, the smaller the chance of things going chronic.
