Glenn Wellmann DPT

Achilles pain has a signature. The first ten minutes of walking in the morning feel stiff and sore. It loosens up once you get moving, sometimes enough that you talk yourself into a run. Then it punishes you that night or the next morning. Hills and speed work make it worse, and squeezing the tendon between your fingers reproduces the exact spot.

That pattern is Achilles tendinopathy: a painful, load sensitive state in the tendon connecting your calf to your heel. It is not a tear, and the tendon is not falling apart. It is telling you the demand you are putting on it has outrun what it is built to handle. The fix the research keeps landing on is not rest. It is a graded increase in load, done in the right position, for long enough to matter.

First, figure out where your pain actually sits

This one detail changes your whole plan, and it gets skipped constantly. Press along the tendon and find the most tender point.

• Midportion: the sore spot is about two to three inches above your heel bone, in the meat of the tendon. This is the most common version, and the one most research covers.
• Insertional: the sore spot is right at the back of the heel bone where the tendon attaches, often with a bump there and pain when the back of a shoe presses on it.

Why it matters: at the insertion, the tendon wraps around bone, so pulling your ankle into a deep toes up position squeezes it. The classic advice to stretch your calf hard and drop your heel below a step can be exactly the wrong dose for an insertional problem, even though it is standard for a midportion one.

Why it happens

Tendons adapt to load, but slowly. Muscle can respond to a new training block in a couple of weeks, and tendon takes longer, so a tendon problem is usually a story about a change: more miles, more hills, flatter shoes, the first three weeks of hockey season after a quiet summer. The load itself was not the villain. The rate of change was.

Then comes the loop. Pain shows up, so you rest completely. The tendon loses capacity while you rest. You feel better, return at your old volume, and the tendon is less prepared than it was the first time. Complete rest fixes the symptom and worsens the cause.

What the evidence actually says

Loading exercise is the anchor, and the specific flavor matters less than doing it. The current American Physical Therapy Association clinical practice guideline for midportion Achilles tendinopathy, revised in 2024, centers management on mechanical loading of the tendon (Chimenti et al., Journal of Orthopaedic and Sports Physical Therapy, 2024). In a randomized trial of 58 people with chronic midportion pain, twelve weeks of heavy slow resistance work and twelve weeks of traditional eccentric heel drops produced equally good results that held at one year, though compliance was better in the heavy slow group, 92 percent versus 78 percent (Beyer et al., American Journal of Sports Medicine, 2015). Translation: pick the loading program you will actually finish.

You probably do not have to stop running. In a randomized study of 38 people, one group kept running and jumping using a pain monitoring rule while the other stopped tendon loading sport for six weeks. Both followed the same rehab program, both improved significantly, and the rate of improvement did not differ (Silbernagel et al., American Journal of Sports Medicine, 2007). Running is not the enemy. Unmanaged jumps in running are.

If your pain is at the insertion, protect the tendon from compression. A 2025 randomized trial put 42 sport active adults with chronic insertional pain through the identical four stage loading program, changing only one thing: one group limited ankle dorsiflexion during exercise, dropped calf stretching, and used heel lifts. That group improved 24.4 points on the Victorian Institute of Sport Assessment questionnaire at twelve weeks versus 12.2 points, a between group difference of 12.9 points (Pringels et al., British Journal of Sports Medicine, 2025). Same exercises, roughly double the improvement, from managing position alone.

One honest caveat: a living network meta-analysis of 29 trials in 1,640 patients found this evidence base is built largely on small studies, a median of 20 patients per treatment arm, which is why no single protocol has been crowned best (van der Vlist et al., British Journal of Sports Medicine, 2021). Give it twelve weeks, not twelve days.

What to do about it

Here is the progression I use, adjusted for where your pain sits. Keep pain during the exercise mild, no more than about a 3 or 4 out of 10, and make sure the next morning is no worse than the last one. That morning check is your real feedback, not how it feels mid set.

1. Week 1 to 2, calm it down with isometrics. Rise onto the balls of both feet and hold. Five holds of 30 to 45 seconds, once or twice a day. If two feet feels easy, shift more weight onto the painful side. Insertional pain: use a small heel lift and do not let the heel drop below level.
2. Week 2 onward, build with heavy slow heel raises three days a week. Three sets, about three seconds up and three seconds down. Start where the last rep of 15 is genuinely hard, then add weight over the weeks so you are near 6 to 8 hard reps by week 8 to 12. A loaded backpack, a dumbbell, or a calf raise machine all work.
3. Do it in two positions. Straight knee heel raises load the bigger calf muscle. Bent knee heel raises, seated or with the knee bent about 45 degrees, bias the soleus, which takes a large share of the load when you run. Alternate sessions between them.
4. Set your range by your diagnosis. Midportion: full range is fine, including letting the heel drop off a step. Insertional: stop at flat ground or slightly above, skip the calf stretch entirely, and keep a heel lift in your daily shoes for the first several weeks.
5. Week 5 or 6, add spring. Once heavy raises feel strong and morning stiffness is fading, add pogo hops or jump rope, 3 sets of 20 to 30 seconds, twice a week, on alternating days from your heavy work.
6. Keep running, but cap the jumps. Hold your longest run inside about 10 percent of your longest run over the past month, limit hills and speed work to one session a week while you rebuild, and put an easy day after your hardest day.

Form cues that matter: rise straight up over your second toe instead of rolling to the outside of the foot, lower under control instead of dropping, and be deliberate about knee position so you train the muscle you meant to train.

Red flags: when to get it looked at in person

• A sudden pop or the feeling of being kicked in the back of the ankle, followed by trouble pushing off. That needs same day medical assessment to rule out a rupture.
• A visible gap in the tendon, or you cannot do a single heel raise on that leg.
• Swelling, redness, and warmth with fever, or pain that wakes you at night unrelated to activity.
• Numbness, pins and needles, or pain traveling down from the buttock, which points somewhere other than the tendon.
• Twelve weeks of honest, progressive loading with no change. Reassess the diagnosis rather than repeat the program louder.
• Recent fluoroquinolone antibiotic use, inflammatory joint disease, or poorly controlled diabetes. Mention these, because they change how cautious we are early on.

Where to go from here

Most stubborn Achilles pain I see is not a mystery. It is a tendon that got asked for more than it was ready for, then handed weeks of rest instead of a plan. If you want that plan built around your pain location, your sport, and the equipment you actually own, that is what a home exercise program is for. If you would rather have someone confirm whether your pain is midportion or insertional first, a comprehensive evaluation sorts that out in one visit. Runners fighting knee pain too can use my six week plan for kneecap pain in runners, and my breakdown of the 2025 rotator cuff tendinopathy guideline shows how these tendon principles apply elsewhere.

References

• Chimenti RL, Neville C, Houck J, Cuddeford T, Carreira D, Martin RL. Achilles Pain, Stiffness, and Muscle Power Deficits: Midportion Achilles Tendinopathy Revision 2024. Clinical Practice Guidelines. Journal of Orthopaedic and Sports Physical Therapy. 2024;54(12):CPG1-CPG32. https://www.jospt.org/doi/10.2519/jospt.2024.0302
• Beyer R, Kongsgaard M, Hougs Kjaer B, Ohlenschlaeger T, Kjaer M, Magnusson SP. Heavy Slow Resistance Versus Eccentric Training as Treatment for Achilles Tendinopathy: A Randomized Controlled Trial. American Journal of Sports Medicine. 2015;43(7):1704-1711. https://pubmed.ncbi.nlm.nih.gov/26018970/
• Silbernagel KG, Thomee R, Eriksson BI, Karlsson J. Continued sports activity, using a pain-monitoring model, during rehabilitation in patients with Achilles tendinopathy: a randomized controlled study. American Journal of Sports Medicine. 2007;35(6):897-906. https://pubmed.ncbi.nlm.nih.gov/17307888/
• 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. https://pubmed.ncbi.nlm.nih.gov/40011018/
• van der Vlist AC, Winters M, Weir A, et al. Which treatment is most effective for patients with Achilles tendinopathy? A living systematic review with network meta-analysis of 29 randomised controlled trials. British Journal of Sports Medicine. 2021;55(5):249-256. https://bjsm.bmj.com/content/55/5/249