If your Achilles pain sits right at the back of your heel, the advice you have probably been given is to stretch the calf and drop your heel off a step. A 2025 randomized trial suggests that for that specific location, the stretching is part of the problem.
The study, briefly
Researchers in Belgium ran an investigator-blinded randomized clinical trial in 42 sport-active adults with chronic insertional Achilles tendinopathy, meaning pain lasting longer than three months right where the tendon attaches to the heel bone. The group was 30 men and 12 women with a mean age of 45.8 years. Everyone was randomly assigned 1 to 1 to either low tendon compression rehabilitation (20 people) or high tendon compression rehabilitation (22 people), and followed for 24 weeks (Pringels et al., British Journal of Sports Medicine, 2025).
Here is the part that makes the trial interesting. Both groups did the exact same progressive four-stage tendon-loading program: isometric holds, then isotonic strength work, then energy storage and release, then sport-specific loading. The only difference was compression management. The low-compression group limited how far the ankle bent upward (dorsiflexion) during exercise, dropped calf stretching entirely, and wore heel lifts. The high-compression group did the same exercises through full range, including stretching. Same dose, same progression, one variable changed.
What they found
The primary outcome was the VISA-A questionnaire, a 0 to 100 score of Achilles pain and function where higher is better. The minimal clinically important difference is about 10 points, so that is the bar for “a patient would actually notice this.”
- At 12 weeks, the low-compression group improved 24.4 points versus 12.2 points in the high-compression group, a between-group difference of 12.9 points (95 percent confidence interval 6.2 to 19.6, p less than 0.001). Roughly double the improvement from the same exercises.
- At 24 weeks the gap held: 29.0 points versus 19.3 points, a difference of 10.4 points (95 percent confidence interval 3.7 to 17.1, p less than 0.001). The high-compression group caught up somewhat but never closed it.
- Both differences cleared the 10-point clinical threshold, so this is not a statistically-significant-but-meaningless finding. It is the size of gap a patient feels.
- Nothing about the strengthening changed. The result came purely from managing compression: less end-range dorsiflexion, no calf stretching, and heel lifts.
Why would that matter mechanically? At the insertion, the tendon wraps around the back of the heel bone. When your ankle bends upward into deep dorsiflexion, the tendon gets squeezed against that bone. Load a tendon and it adapts. Squash it repeatedly and it stays irritated. Stretching your calf and hanging your heel off a step both drive the ankle into exactly the position that compresses the sore spot.
The catch
This was 42 people at a single center, which is small. Confidence intervals that wide (6.2 to 19.6 points at 12 weeks) tell you the true effect could be modest or large. The participants were sport-active adults averaging 46 years old, so the findings may not transfer cleanly to sedentary, older, or diabetic patients, and follow-up stopped at 24 weeks, so nothing here speaks to two years out.
The bigger caveat is where your pain is. This trial studied insertional tendinopathy, pain at the heel bone itself. Mid-portion Achilles tendinopathy, the kind that hurts two to six centimeters up from the heel, is a different problem with different rules, and the classic heel-drop protocols were developed and validated for it. Applying insertional rules to a mid-portion tendon means leaving useful range on the table. This is the same theme as with other stubborn tendons: the location and the load history change the plan, which is why I keep coming back to it, as in my post on gluteal tendinopathy and hip compression.
What this means for you
First, find out which one you have. Press along the tendon with one finger. If the tenderness is right at the bony back of the heel where the tendon inserts, that is insertional. If the tender spot is a few centimeters higher in the cord of the tendon itself, that is mid-portion. Insertional pain also tends to be worse in stiff shoes with a rigid heel counter, and worse on hills or stairs.
If it is insertional, three changes follow directly from this trial:
- Stop stretching your calf. No wall stretch, no leaning off a curb, no calf stretch on the stairs. It feels productive and it compresses the exact tissue you are trying to settle.
- Keep the heel above neutral during strength work. Do calf raises off flat ground or with a small wedge under the heel, and stop the lowering phase at the floor rather than dropping below a step. Full range is not the goal right now.
- Add a heel lift. Roughly 8 to 12 millimeters in your everyday shoes, both sides, takes the tendon out of the squeeze all day long. Flat, minimalist shoes and barefoot walking on hard floors tend to aggravate it.
Then load it, because the loading program was the treatment in both groups. A reasonable progression that mirrors the trial’s four stages:
- Stage 1, isometrics. Double-leg calf raise hold at mid-range on flat ground, 5 holds of 30 to 45 seconds, once or twice daily. Cue: weight through the big toe, heel straight up, no rolling out.
- Stage 2, isotonic strength. Double-leg then single-leg calf raises on flat ground, 3 sets of 12, four days a week, adding load with a backpack or dumbbell. Stop at the floor on the way down. Add a seated calf raise for the soleus.
- Stage 3, energy storage. Once strength work sits comfortably under 4 out of 10, add small hops, skipping, and short pogo work on flat ground, two or three days a week.
- Stage 4, sport-specific. Rebuild running or court work gradually, keeping hills and speed for last. Flat terrain first.
Use the same rule I use in the clinic: pain of 4 out of 10 or less during the exercise, and back to your normal baseline within 24 hours. Tendons respond to consistency over months, not to hard weeks. In this trial the improvement was still climbing between 12 and 24 weeks, so give it a real six months before you decide it is not working.
Where to go from here
The single highest-value thing you can do with this information is confirm where your pain actually is, because the compression rules flip between insertional and mid-portion. That takes about five minutes of hands-on exam, and getting it wrong costs months. If your heel pain has been dragging on and nobody has told you which type you have, a comprehensive evaluation gives us a full hour to sort it out, test your calf capacity, and build the staged program around your shoes, your running, and your winter plans. If you already know it is insertional and just want the loading program written and progressed for you, that is my home exercise program service.
References
- Pringels L, Capelleman R, Van den Abeele A, Burssens A, Planckaert G, Wezenbeek E, Vanden Bossche L. Effectiveness of reducing tendon compression in the rehabilitation of insertional Achilles tendinopathy: a randomised clinical trial. British Journal of Sports Medicine. 2025;59(9):640-650. doi:10.1136/bjsports-2024-109138. https://pubmed.ncbi.nlm.nih.gov/40011018/
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