That day, past the eighth kilometer, the tendon at the back of your right heel started to twinge, and every push-off made it twinge a little more. The next morning, wheeling your motorbike out to the lane, you had to put your whole right foot down flat to get over the doorstep. You decided to rest completely so the tendon could heal. Over those three weeks, the ice packs in the freezer dwindled, getting the bike over the doorstep became easy again, and the tendon hardly hurt at all.
Last Sunday you went running again. By the third kilometer, the old spot flared up as if you had never rested a single day.
This happens to a lot of runners. The 2024 clinical practice guideline on Achilles tendinopathy ranks loading exercise for the tendon as first-line treatment. Heel pain from the plantar fascia (the taut band of tissue under the sole of the foot) is treated along the same lines.
The cord that joins the calf to the heel
The Achilles tendon is the shared end of the gastrocnemius and soleus, the two muscle masses of the calf, and it attaches to the back of the heel bone. With every running stride, this tendon pulls the heel up to push the body forward. The orthopedic medicine textbook by Atkins and colleagues cites a figure of about 12.5 times body weight passing through the tendon.
In runners, this is the spot that breaks down most often. In reviews of running injuries (Videbæk and colleagues, 2015; Kakouris and colleagues, 2021), Achilles tendinopathy comes first, at about 10 % of new injuries, with plantar fasciitis at about 6 %. Men get Achilles tendinopathy more often than women, at nearly double the risk (Hollander and colleagues, 2021).
The usual pattern in runners is pain in the middle section of the tendon, some distance above where it attaches to the heel, known as midportion Achilles tendinopathy. People commonly call it tendinitis. The guideline in JOSPT, the journal of orthopaedic and sports physical therapy (Chimenti and colleagues, 2024), and the Atkins textbook both class it as a degenerative condition of the tendon, so it is managed differently.
Three weeks of ice
The guideline on midportion Achilles tendinopathy published in JOSPT in 2024 grades each measure by strength of recommendation quite clearly. Loading exercise for the tendon is first-line treatment, at the highest level. Not needing complete rest: moderate level. Heel lifts in the shoe for a short period: weak level. Laser and ultrasound used on their own are not recommended. Manual therapy and dry needling (inserting needles into tight knots in the muscle) stay at the level of expert opinion.
As we understand it, complete rest removes the load that causes pain, but it also removes the very thing the tendon needs in order to adapt. Three weeks of ice quiets the pain. The tendon’s capacity to bear load, however, stays where it was, so the first run puts it straight back under the same old load.
Let the tendon work, but do not grit your teeth and run through the pain. Cuthbert, in his book on Applied Kinesiology (AK, a method of testing muscle strength by hand to read the state of the body) for the lower body, notes that the recovery phase usually calls for a considerable cut in training volume (p. 237). Long runs and hill runs may need to be reduced for a while, while tendon sessions become more regular than before.
Some people ask for an injection to speed things up. The clinic does not give injections, and there is reason to be wary. Cuthbert notes that corticosteroids (a strong type of anti-inflammatory medicine), whether injected into the painful spot or taken by another route, increase the chance of rupturing both the Achilles tendon and the plantar fascia. The medicine eases the pain, so people train harder, and then the tendon tears partly or completely (p. 238).
Very slow heel raises, heavier week by week
Two ways of loading the tendon have been tested the most. One is Alfredson’s eccentric method, which focuses on lowering the heel very slowly. The other is heavy slow resistance, rising up and lowering down equally slowly, with the load increasing gradually. Alfredson’s original study (1998) had only 15 people. Beyer and colleagues (2015) put the two methods side by side in a randomized trial and found them equally effective, but patients found heavy slow resistance easier to stick with. Maetz and colleagues (2023) pooled 12 randomized trials and also found no protocol clearly better than any other.
JOSPT uses the phrase “high load as tolerated” (that is, as heavy as the tendon can still bear) and suggests at least three sessions a week, at a lower grade of recommendation. How heavy that load is, and how many repetitions per session, the guideline does not give as a single figure. That is why the exercise needs someone to guide it: to set the starting level and watch how the tendon responds over the sessions before increasing it.
If your pain is right where the tendon attaches to the heel, adjust a little. Joyce and Lewindon (2016), along with Atkins, advise doing the exercise on flat ground in that case, without letting the heel drop below the level of the step.
As for diet, gelatin with vitamin C taken before a training session has so far only been shown to raise blood markers signaling that the body is making collagen (Shaw and colleagues, 2017); the evidence that it changes the structure of the tendon is very low, and nothing yet shows that it prevents injury (Bischof and colleagues, 2024).
The spur on the heel X-ray
Pain under the heel, worst in the first few steps of the morning, is usually plantar fasciitis, involving the taut band of tissue under the sole of the foot. Many people get an X-ray, see a spur jutting out of the heel bone and believe they have found the culprit. Atkins and colleagues note that heel spurs are found in about half of people with plantar fasciitis, and in as many as 19 % of people who do not have it. The spur on the X-ray therefore does not help with the diagnosis.
The JOSPT clinical practice guideline on heel pain (Koc and colleagues, 2023) places several measures at the highest level: specific stretches for the plantar fascia and the calf, taping, and a night splint worn for 1–3 months for people whose pain comes in the first steps of the morning. Manual therapy is also at this level; the clinic does not provide it, and anyone who needs it will be referred to a suitable place. The stretches you do yourself at home, following instructions. At the moderate level is resistance training (exercise against a resisting force) for the foot and ankle, which means the plantar fascia also needs to be loaded again. Shoe inserts should not be used on their own.
Most heel pain of this kind clears up on its own within a year. The figure often quoted is 90–95 %, taken from what books cite; we have not been able to check it against the original source, but even so, that is enough to worry less and be patient with the exercises.
Tired calves after a day on your feet
In AK, the gastrocnemius and soleus, the two muscles that both feed into the Achilles tendon, are classed as related to the adrenal glands (Walther, Synopsis, p. 329; Cuthbert, p. 14–16). These two muscles are very strong. When testing them, the examiner’s hand can only press against the foot, a short lever, so it is hard to overpower them enough to see a shortfall. Cuthbert therefore also reads what he calls body language: calves that feel tired and achy after standing a long time, and, during the examination, pain as soon as the calf is squeezed gently (p. 18). Goodheart observed that when a patient holds in the mouth an adrenal-support substance that suits them, that pain often eases (cited in Cuthbert, p. 15). Cuthbert also stresses that this pain must be distinguished from vascular disease and from metabolic disorders within the muscle itself.
For people with heel tendon pain, the clinic starts from the very movement the tendon has to make with every running stride. You rise onto your toes on one leg, resting a hand lightly against the wall, exactly the standing test Cuthbert describes (p. 14). If you have to bend the knee or lean forward to get up, the gastrocnemius and soleus are working below threshold, meaning they go weak when muscle tested (inhibited muscle). While you are standing, the doctor also looks at your feet. According to Cuthbert, extended pronation, in which the arch of the foot rolls inward and does not lift back up at the right moment, and short, poorly stretching calf muscles are the two factors most often linked with Achilles tendinopathy (p. 237).
Next comes the tendon itself. Muscle spindles (neuromuscular spindle cells) sit in the belly of the muscle and report its length. Golgi tendon organs sit in the tendon, near where it joins the muscle, and report tension. These two kinds of sensors, together called proprioceptors, can misreport after an injury, making the muscle go weak or tight (Walther, Synopsis, p. 62–64). Loram (2009) notes that in the Achilles tendon, the information from these two places needs to match, and when it does not, the whole tendon–muscle unit is more easily injured; Cuthbert cites this idea (p. 238) and reports that in the gastrocnemius and soleus, the disturbance he finds most often is in exactly the muscle spindles or the Golgi tendon organs (p. 17).
To find that spot, you place your own hand on the calf, then on the tendon, and the doctor retests the muscle after each one. AK calls this step therapy localization. Wherever the muscle changes, the doctor stimulates the signal there again, sometimes also tapping a deep tendon reflex using Palomar’s P-DTR method (Proprioceptive Deep Tendon Reflex) so that the nervous system takes in the correct signal again (Palomar, p. 13–17). All the techniques are gentle, and none of the steps is massage.
The adrenal side gets more careful questioning in people heading into race season. Walther lists what weighs on these glands: living or working around chemicals, pushing yourself to train hard while sleeping little, and emotional stress (Synopsis, p. 515). A packed training season often brings all of these together. Garten lists for the gastrocnemius the vitamins B2, B5, B6, B9, B12, vitamin C and tyrosine, substances that the enzymes of the adrenal glands need in order to work (Muscle Test Handbook, p. 95); the doctor tests each substance on your muscles, and only those that suit you are considered.
The clinic’s experience is that once the signals in the calf have been reset, the load in the heel-raise exercise can be increased faster. Cuthbert also advises not returning to running until the AK examination shows the structure is balanced (p. 237–238). Calf pain also does not mean the adrenal glands are diseased, and if the doctor suspects a torn tendon, you will still be sent for an ultrasound.
The heel in the old texts
The Zhenjiu Dacheng (针灸大成 / 針灸大成, Great Compendium of Acupuncture and Moxibustion) traces heel pain to three causes: overwork (working beyond your strength), congealed dampness (damp qi stagnating and building up), and coming home hot from a long walk in the heat and then soaking in cold water (volume 2, p. 259). That last one sounds very close to the old advice from grandparents not to bathe right after coming in from the sun. For someone with long-lasting heel pain who feels tired and is slow to regain strength after the training season, once blood test results are available, the doctor may consider adding a decoction that tonifies qi and blood, in ready-to-drink 50 ml pouches. The heel-raise exercise is still the main job; the decoction follows behind.
When to see a doctor
Get examined right away, without waiting, if:
- You hear a “pop” at the back of the heel, cannot rise onto your toes, and squeezing the calf does not make the foot flex downward, signs of a ruptured tendon (Hattam and Smeatham);
- The pain is concentrated in the heel bone rather than the tendon or the sole, gets clearer with each run, and hurts even when lying at rest;
- The tendon swells into a lump, or the tendon hurts even while sitting still, not only when running.
The heel is one of the places where runners can get a stress fracture (a bone cracking gradually from repeated loading), and it needs imaging when the doctor orders it. According to Cuthbert, a tendon swollen into a lump that hurts even at rest suggests the tendon has degenerated badly or is partly torn. He also points out that Achilles tendon pain is easily mistaken for tarsal tunnel syndrome, a tibial stress fracture, or posterior tibial tendinopathy (p. 237).
Book a visit when heel pain has lasted a few weeks and regular exercise has not helped, when the pain comes back in exactly the same spot every time you return to running, or when your calves stay tired and achy after days of standing a lot.
Put the ice pack away, start the heel raises
Now that the tendon has settled, this is an easier time to start again. The first thing is the slow heel-raise exercise, three sessions a week, with the load increased gradually under the guidance of whoever is supervising you. Short runs on flat roads come back later, once your supervisor sees that the tendon can handle the load of the exercise and the AK examination shows the calf is working well enough. Long runs and hills come last. Each morning, wheeling the bike over the doorstep, you will still keep an eye on your right heel; the only difference is that this time the tendon has a job to do.
A consultation with Dr. Dinh Ngoc Duc (MD, MSc in Traditional Medicine) starts with the single-leg heel-raise test. If the tendon shows signs that call for an ultrasound or a specialist, you will know that same day; if not, you go home with a starting load for your own exercise program. Book a consultation.
Worth keeping
- A painful Achilles tendon still needs to work, in measured doses;
- Do tendon loading exercises, such as slow heel raises with gradually heavier loads, at least three sessions a week, with someone guiding you;
- If the pain is right where the tendon attaches to the heel, do heel raises on flat ground, without letting the heel drop below the level of the step;
- For pain under the heel in the morning, stretch the plantar fascia and calf yourself as instructed, and do not be quick to blame the spur on the X-ray;
- Do not look for a corticosteroid injection into the tendon to make the pain go away quickly;
- If you hear a “pop” at the back of the heel and cannot rise onto your toes, see a doctor right away;
- If your calves are tired and achy after days of standing a long time and the tendon keeps hurting again when you run, get an AK examination to find out why the gastrocnemius and soleus are working below threshold.
References
Sources in Vietnamese
- Châm cứu đại thành. Quyển 2. Tr. 259.
Sources in English
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