Tendinopathy rehabilitation
Evidence: strong
Achilles and patellar tendinopathy respond to progressive loading better than to any passive treatment, and eccentric and heavy-slow resistance protocols give similar results. The catch is time: recovery runs over months, and there is no quick fix.
Not medical advice
This is a general knowledge base, not medical or dietary advice. If you are injured, unwell or weighing up a supplement or a change to your diet, speak to a doctor, physiotherapist or registered dietitian who knows your situation.
Tendinopathy is the modern name for a painful, load-related tendon problem, most often at the Achilles or the patellar tendon. The old name ‘tendinitis’ implied inflammation, but histology of chronic tendon pain shows little classic inflammation. What it shows is a load-driven change in the tendon’s cells and matrix, with collagen becoming disorganised (Cook & Purdam 2009). This matters for treatment: a degenerative, load-related problem responds to graded loading, not to rest and anti-inflammatories alone.
Loading is the treatment
The strongest evidence in tendon rehab is that loading the tendon beats passive treatment. Systematic reviews and meta-analyses of RCTs find loading-based exercise superior to passive modalities such as ultrasound or rest for midportion Achilles tendinopathy (Maetz et al. 2023).
Two loading styles dominate, and they work about equally well. The eccentric (Alfredson) protocol uses slow heel-drop lowering, traditionally a high daily volume. Heavy-slow resistance uses fewer, heavier, slow repetitions every second or third day. A head-to-head RCT in midportion Achilles tendinopathy found both produced large, lasting gains, with mean VISA-A scores rising from 74 at 12 weeks to 87 at one year and no difference between groups, though heavy-slow resistance won on patient satisfaction (Beyer et al. 2015), and its lower session frequency makes it the more convenient programme in practice.
The same picture holds at the patellar tendon. An RCT comparing corticosteroid injection, eccentric decline-squat training and heavy-slow resistance found all three eased symptoms in the short term, but the steroid group relapsed, while heavy-slow resistance gave good results at both short and long term alongside improved tendon structure and collagen turnover (Kongsgaard et al. 2009). A subsequent network meta-analysis of 37 RCTs confirmed that eccentric loading with or without adjuncts remains first-line, and found ESWT no better than sham when eccentric exercise was included (Challoumas et al. 2021).
Pick the protocol you will actually do
Eccentric and heavy-slow loading give similar outcomes, so adherence decides (Beyer et al. 2015). Heavy-slow resistance asks for fewer sessions and tends to be better tolerated, which makes it the easier programme to stick to over the months recovery takes.
Pain monitoring, not pain avoidance
Tendons can be loaded into a moderate level of pain during rehab without harm, which separates tendon work from bone stress injury. A widely used rule, from the Silbernagel pain-monitoring model, allows discomfort up to about 5 out of 10 during loading, provided it settles to baseline by the next morning and does not climb week to week (Silbernagel et al. 2007). Pain within that window is acceptable and does not signal damage. Pain that lingers into the next day, or worsens week to week, means the load was too high and should be reduced.
The carbon-plate caveat from bone injuries does not apply here; tendon rehab is about graded loading rather than offloading.
It takes months
The hardest part of tendon rehab is the timescale. Meaningful change takes weeks, and full recovery often runs to three months or more, with continued improvement out to a year (Beyer et al. 2015). Tendon adapts slowly, so there is no shortcut. Injections, in particular, can give short-term relief but tend to underperform loading in the long run (Kongsgaard et al. 2009).
Manage expectations from the start
Runners often abandon tendon rehab because it feels slow. The evidence says slow is normal: the gains accrue over months, not weeks (Beyer et al. 2015). Setting that expectation early is part of the treatment.
A practical course is to begin isometric or light loading to settle irritable symptoms, progress to heavy-slow resistance two to three times a week, and keep a reduced amount of running going if it stays within the pain rule. If loading stalls, shockwave therapy is the best-evidenced passive adjunct to add, with moderate support in chronic tendinopathy (ESWT Achilles review 2022); the other hands-on treatments offer short-term relief at best. Collagen peptide supplementation (15 g daily for at least eight weeks) combined with loading may also improve tendon cross-sectional area, though certainty of evidence for tendon-specific outcomes is very low (Bischof et al. 2024). Strength work also lowers the chance of the injury returning; see strength training for runners. The springy efficiency a healthy Achilles provides is itself worth protecting; see Achilles stiffness and economy.