“I’ve got tendonitis in my Achilles” is something I hear at least three times a week. And I get it — it’s the term your GP probably used, it’s what comes up when you Google, and it sounds like a proper medical diagnosis.
But here’s the problem: if you’ve had that pain for more than a few weeks, it’s almost certainly not tendonitis. And that distinction isn’t just academic word-games — it fundamentally changes how we should be treating it. Rest and anti-inflammatories might sound sensible for “tendonitis”, but for what’s actually going on in your tendon, they’re often the worst thing you could do.
“Tendonitis” implies inflammation, but most chronic tendon pain is actually tendinopathy — a failed healing response, not active inflammation. This matters because anti-inflammatories and rest won’t fix it; progressive loading will.
Let me explain what’s really happening, and why getting the terminology right changes everything about your recovery.
The “-itis” Problem
That suffix — “-itis” — means inflammation. Appendicitis, tonsillitis, arthritis. Acute inflammation: swelling, heat, redness, the whole immune system response.
And yes, in the first few days after you’ve irritated a tendon, there is some inflammation. That’s a reactive tendon — your body responding to an overload with an inflammatory process. If you’ve just ramped up training too quickly or done something unusually intense, you might genuinely have acute inflammation for a week or two.
But most people I see in the clinic in Chester haven’t had pain for a week. They’ve had it for months. Maybe years. And research over the past 20 years has shown pretty clearly that chronic tendon pain isn’t primarily an inflammatory problem — it’s a structural one.
When scientists actually look at these painful tendons under a microscope, they don’t find lots of inflammatory cells. They find disorganised collagen, failed healing responses, increased ground substance, sometimes tiny tears that haven’t healed properly. The tendon structure has changed. That’s tendinopathy — a disease process in the tendon itself.
What’s Actually Happening in Tendinopathy
Think of a healthy tendon as tightly organised bundles of collagen fibres, all lined up in the same direction like rope. Strong, efficient, capable of handling massive loads.
In tendinopathy, that organisation breaks down. The collagen becomes disorganised — more like a tangled mess than a rope. The cells that maintain the tendon (tenocytes) start behaving abnormally. The tendon tries to heal but can’t quite manage it, ending up in a chronic state of failed repair.
This happens on a continuum, and understanding where you are on that continuum matters (Cook & Purdam, 2009):
Reactive tendinopathy — short-term overload, the tendon swells up a bit, mostly reversible if you manage the load properly. This is the closest thing to genuine “tendonitis” and it responds well to a bit of relative rest and gradual return to activity.
Tendon dysrepair — the tendon has been overloaded for longer, and you’re starting to get structural changes. Still largely reversible with the right approach, but now we need a proper progressive loading programme.
Degenerative tendinopathy — long-standing changes, areas of the tendon that are genuinely degenerate. Harder to reverse, but even here, tendons can still be strengthened and made functional again.
Most people who’ve had pain for several months are somewhere between dysrepair and degeneration. And here’s the critical bit: these tendons don’t need less load, they need the right load, progressively applied.
Pain that's been around for months
If it's longer than 6-8 weeks, inflammation isn't the primary driver anymore — you're dealing with structural changes in the tendon
Rest makes it feel better... temporarily
The pain eases when you rest, but it comes straight back when you return to activity — classic tendinopathy behaviour
Morning stiffness that 'warms up'
The tendon feels stiff and painful first thing, eases as you move, then gets worse again with prolonged activity
Progressive worsening despite rest
You've tried resting, you've tried ice, maybe even taken anti-inflammatories for weeks — but it's not resolving
Why the Wrong Label Leads to the Wrong Treatment
This is where the terminology really matters. If you think you’ve got tendonitis — inflammation — then the logical treatment is anti-inflammatory measures. Rest it. Ice it. Take ibuprofen. Maybe get a steroid injection to “calm it down”.
And I see people who’ve been doing exactly that for months. Sometimes years. And they’re still in pain, still limited, still frustrated.
Because those treatments don’t address the structural problem. In fact, there’s growing evidence that some of them might actually make things worse:
Rest — makes the tendon weaker and less tolerant of load, so when you do return to activity, it’s even less capable of handling it.
Ice — might help with acute pain, but does nothing for the underlying structural changes. Some research suggests prolonged ice use might even interfere with the healing process.
Anti-inflammatories — can reduce pain in the short term, but if inflammation isn’t the main problem, you’re just masking symptoms. And there’s some evidence they might interfere with tendon healing.
Steroid injections — this is the big one.
Steroid injections can give dramatic short-term pain relief for tendinopathy — I’ve seen people walk out of a GP clinic pain-free after months of suffering. But here’s what the research shows: while they might help for a few weeks, outcomes at 6 and 12 months are often worse than doing nothing.
Steroids can weaken tendon tissue, interfere with collagen synthesis, and in some cases increase the risk of tendon rupture. For Achilles tendinopathy, the evidence is particularly clear — steroid injections are best avoided entirely due to rupture risk.
If someone’s offering you a steroid injection for chronic tendon pain, make sure they’ve explained why the short-term relief might come at the cost of long-term tendon health. Usually, there’s a better option.
What Actually Works: Progressive Loading
The evidence is pretty clear now: tendons need load to heal. Not random load, not too much too soon, but structured, progressive loading that gives the tendon the stimulus it needs to remodel and strengthen (Lauersen et al., 2014).
This is the complete opposite of the “rest until it’s better” approach. And it takes a mental shift — we’re asking painful tendons to do work. But done properly, it’s the most effective treatment we have.
A proper tendinopathy rehabilitation programme typically follows this pattern:
Isometric loading (weeks 1-3) — holding static positions under load. This can reduce pain fairly quickly and starts the strengthening process without aggravating the tendon too much.
Heavy slow resistance (weeks 4-12+) — progressive strengthening exercises, usually with fairly heavy weights and slow movement. This is where the real structural remodelling happens. We’re talking 3-4 sets of 8-12 reps, 3-4 times per week, gradually increasing load over months.
Energy storage and release (weeks 12+) — plyometric and sport-specific loading. For runners with Achilles problems, this might be hopping and jumping progressions. For tennis elbow, it’s returning to serving and hitting.
The timeline there isn’t arbitrary. Tendons are slow to adapt. The research suggests meaningful structural changes take at least 12 weeks, often more like 6 months. Anyone promising a quick fix is talking rubbish.
| Factor | Tendonitis (acute) | Tendinopathy (chronic) |
|---|---|---|
| Duration | Under 2 weeks | Over 6 weeks |
| Primary issue | Inflammation | Failed healing/disrepair |
| Best treatment | Relative rest, anti-inflammatories | Progressive loading |
| Imaging findings | Swelling | Thickened, disorganised tendon |
| Recovery timeline | 2–4 weeks | 3–6 months |
Old Approach: 'Tendonitis'
Rest, ice, anti-inflammatories, avoid painful activities, maybe a steroid injection, wait for it to 'heal'
Evidence-Based: 'Tendinopathy'
Progressive loading programme, maintain modified activity, address contributing factors (strength, biomechanics), patience with 3-6 month timeline
Common Sites and Their Quirks
While the underlying principles are similar, different tendons have their own characteristics:
Achilles tendinopathy — probably the most common one I treat, particularly in runners around Liverpool and across Cheshire. The Achilles responds well to heavy calf raises, but you need to be patient. Minimum 12 weeks, often 6 months for full return to running volume. I’ve written more detail on Achilles-specific treatment here.
Patellar tendinopathy (jumper’s knee) — common in sports with lots of jumping and landing. Responds to similar principles but needs careful load management — it’s easy to overdo it.
Lateral elbow tendinopathy (tennis elbow) — less about rest, more about progressive grip strengthening and wrist extension exercises. Often responds well to shockwave therapy as an adjunct to loading programmes.
Medial elbow tendinopathy (golfer’s elbow) — similar approach, different exercises. Wrist flexion and forearm pronation strengthening.
Rotator cuff tendinopathy — needs assessment of shoulder mechanics and scapular control as well as direct rotator cuff strengthening. Often multiple tendons involved.
The Reality of Recovery
Here’s what I tell people when they come in with chronic tendon pain: this is fixable, but it requires work and patience.
You’ll need to do exercises most days. They’ll probably be a bit uncomfortable — we’re asking irritable tendons to work, after all. But we’re not looking for severe pain, and we adjust the programme as we go based on how your tendon responds.
You’ll need to modify your activity, but not stop completely. A runner with Achilles tendinopathy might need to reduce mileage and avoid hills for a while, but total rest usually makes things worse.
And you need realistic timescales. Three months minimum before you should expect major improvement. Six months isn’t unusual. I know that’s frustrating when you just want to get back to normal, but tendons are slow. That’s biology, not pessimism.
The good news? When you do put in that work, success rates are high. Most people with tendinopathy can get back to full activity with a properly structured programme. But it requires ditching the “tendonitis” mindset and embracing progressive loading.
When to Get Help
You can manage some mild tendon issues yourself with the right information. But you should see someone if:
- Pain has been present for more than a few weeks despite modifying activity
- Pain is significantly limiting what you can do day-to-day or in sport
- You’ve tried rest and it keeps coming back when you resume activity
- You’re not sure what exercises are appropriate or how to progress them
- Pain is severe or you’re worried about a possible tear
A proper assessment can identify exactly which tendon is involved, where you are on the reactive-to-degenerative continuum, what load you can currently handle, and what the contributing factors are (weakness, biomechanics, training errors).
From there, we can build a progressive loading programme tailored to your specific situation and goals. Not generic advice, not one-size-fits-all, but a structured plan with clear progressions and realistic timescales.
The Bottom Line
The shift from “tendonitis” to “tendinopathy” isn’t just semantics — it represents a fundamental change in how we understand and treat these injuries (Cook & Purdam, 2009).
Inflammation might be part of the picture in acute, reactive tendons. But for most people with chronic tendon pain, the primary problem is structural changes in the tendon itself. And that needs a completely different approach: progressive loading, not rest and anti-inflammatories.
Your GP might still use the term “tendonitis” — the terminology is slow to filter through, and it’s what most patients recognise. But the important thing is the treatment approach: if someone’s offering you rest and steroid injections for a tendon problem that’s been going on for months, ask whether a progressive loading programme might be more appropriate.
Because the evidence is clear: for most tendinopathy, load is medicine. The right load, progressively applied, over a realistic timeline. That’s what gets people better.
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