Achilles tendon pain has one of the clearest answers in musculoskeletal medicine: load the tendon, progressively, for about three months, and most people get substantially better. The evidence for loading is well established and it is the core of any sensible plan.
The difficulty is not knowing what to do. It is that the programme takes twelve weeks, the first few of those are uncomfortable, and a large share of people stop before it has had time to work. Most of the clinical skill in treating this condition goes into making the exercise possible — and that is where the rest of a plan, including adjunctive therapies, earns its place.
What Achilles tendinopathy actually is
It is a change in the tendon from repeated load that outpaced the tendon’s capacity to adapt. Typically it presents as pain and stiffness at the back of the heel or two to six centimetres above it, worst on the first steps in the morning, easing with light activity and then returning afterwards. Runners get it, but so do people who walk a lot on hard surfaces, who changed footwear, who increased their step count quickly, or who simply have a job that keeps them standing.
Two distinctions matter because they change the treatment:
Midportion versus insertional. Pain in the tendon body a few centimetres above the heel bone is midportion tendinopathy. Pain right at the bone is insertional, and it does not tolerate the same exercise range — stretching the tendon into full dorsiflexion tends to aggravate it. Getting this wrong is a common reason a correct-sounding programme fails.
Tendinopathy versus rupture. Gradual-onset pain that builds over weeks is tendinopathy. A sudden sharp pain, often with an audible pop and real difficulty pushing off or standing on tiptoe, may be a tear and needs same-day assessment. If that describes you, do not read on — get seen.
Why loading is the treatment
Tendon responds to mechanical load. A structured programme that puts controlled, progressive tension through the tendon improves pain and function in the large majority of cases of midportion tendinopathy, and it remains first-line care in mainstream guidance. Nothing in this article changes that. Rest alone does not work well here — it reduces pain in the short term and reduces the tendon’s capacity at the same time, so symptoms return when activity resumes.
We set out the actual programme, including the sets, frequency and how to progress, in The Eccentric Loading Program, Explained.
The real obstacle: it works slowly
The onset of benefit from eccentric loading is slow. People are typically asked to do a somewhat painful exercise twice a day, every day, for three months, with meaningful improvement often not obvious for the first four to six weeks. That is a hard thing to ask, and adherence is the single biggest predictor of whether it works.
So the practical question in clinic is not “what else could we do instead.” It is “what reduces pain enough, early enough, that this person actually completes the programme.”
Where photobiomodulation fits
This is the specific gap that the best Achilles evidence addresses. A randomized, placebo-controlled trial published in the American Journal of Sports Medicine enrolled 52 recreational athletes with chronic Achilles tendinopathy and randomized them to an eccentric exercise programme plus low-level laser therapy, or the same programme plus placebo laser, over eight weeks. Treatment was 820 nm light delivered in 12 sessions, irradiating six points along the tendon at a power density of 60 mW/cm² for a total dose of 5.4 J per session.
Pain during physical activity, measured on a 100 mm visual analogue scale, was lower in the laser group at every time point: 53.6 mm versus 71.5 mm at 4 weeks (P = .0003), 37.3 mm versus 62.8 mm at 8 weeks (P = .0002), and 33.0 mm versus 53.0 mm at 12 weeks (P = .007). Secondary measures — morning stiffness, active dorsiflexion, tenderness on palpation and crepitation — followed the same direction.
The finding that matters most in practice is the timing. The laser group’s results at 4 weeks were about where the placebo group arrived at 12 weeks. The authors’ conclusion was that the light therapy accelerated clinical recovery when added to an eccentric exercise regimen. That is exactly the role we use it for: it does not replace the loading programme, it makes the early weeks tolerable enough to get through.
Worth being precise about what this is: a single randomized trial of 52 recreational athletes, using one specific set of parameters, and the comparison is exercise-plus-light against exercise-plus-placebo — so the exercise is doing the structural work in both arms. A 2025 umbrella review of photobiomodulation across 204 randomized trials reached a similar overall position, concluding that the therapy has real effects in several conditions while calling for further high-quality trials and standardization of treatment parameters. We frame it as an adjunct with a defined job, and photobiomodulation is not FDA-cleared for the treatment of Achilles tendinopathy.
The wavelength and the target site are not incidental details, which is a theme across the tendon literature — we wrote about the same issue in Tennis Elbow: The Wavelength and Where You Point It. If you want the underlying mechanism, see What Photobiomodulation Actually Is.
The rest of the plan
A few things do more than people expect, and none of them involve a device:
- A heel lift, temporarily, for insertional pain. It offloads the irritated attachment while the programme gets going.
- Footwear review. A sudden change to a flatter or more minimal shoe is a frequent trigger.
- Load management, not rest. Reduce the aggravating activity to a level the tendon tolerates, keep moving, and rebuild from there.
- Calf and gluteal strength beyond the tendon itself, because the tendon is loaded by what happens above and below it.
- Patience with a plan and a date. We agree in advance when we will reassess, so progress is a measurement rather than an impression.
What a first visit looks like
We confirm the diagnosis and locate the pain precisely, because midportion and insertional are managed differently. We check what changed in the weeks before symptoms started, look at footwear and training load, examine calf strength and ankle range, and screen for the less common causes of posterior heel pain that need a different route entirely. Then we build the loading programme, set the reassessment date, and discuss an adjunct if the early-weeks pain looks likely to be the thing that derails it.
If you have had morning heel stiffness for more than a few weeks, the programme is worth starting properly rather than starting three times.
References
- Stergioulas A, Stergioula M, Aarskog R, Lopes-Martins RAB, Bjordal JM. Effects of low-level laser therapy and eccentric exercises in the treatment of recreational athletes with chronic achilles tendinopathy. The American Journal of Sports Medicine. 2008;36(5):881–887. PMID 18272794. doi:10.1177/0363546507312165
- Son Y, Lee H, Yu S, et al. Effects of photobiomodulation on multiple health outcomes: an umbrella review of randomized clinical trials. Systematic Reviews. 2025;14(1):160. PMID 40770824. doi:10.1186/s13643-025-02902-3
Citations retrieved from PubMed.
This article is general education, not medical advice, and it is not a substitute for evaluation by a qualified clinician. It does not establish a physician–patient relationship. Individual results vary, and the studies described report group averages rather than what any one person should expect. Treatments discussed may not be FDA-cleared or approved for the conditions mentioned; where that is the case it is stated in the text. Talk to your own physician before starting, stopping or changing any treatment.
