If the worst pain of your day is the first few steps out of bed, or off the sofa after sitting still for a while, and it then eases as you keep moving — that pattern alone is close to diagnostic. It’s the classic presentation of Achilles tendinopathy, and it means the tendon has stopped tolerating the load you’re putting through it. The good news: this is one of the best-understood conditions in sports physiotherapy, with a clear, evidence-based route back to full function. It’s just not a quick one.
What’s actually happening in the tendon
“Tendinitis” implies inflammation, and for years that’s how this was treated — rest, ice, anti-inflammatories. We now know that’s largely the wrong model. Biopsies of painful Achilles tendons rarely show inflammatory cells. What they show is disorganised collagen structure, increased ground substance, and abnormal blood vessel and nerve ingrowth — a failed healing response rather than an active inflammatory one. That’s why the term has shifted to tendinopathy, and why anti-inflammatory approaches (rest, ice, steroid injections) tend to give short-term relief but don’t fix the underlying problem, and can occasionally make it worse.
The tendon needs load to remodel — but the right amount, at the right stage, progressed in the right order. Too little load and it never adapts. Too much, too soon, and you aggravate it further. This is the balance rehab is built around.
Stage 1: isometric loading — calming the tendon down
If you’re in an acute, high-pain phase, start here. Isometric holds (holding a muscle contraction with no movement) have been shown in research by Ebonie Rio and colleagues at Monash University to reduce tendon pain within minutes, likely through a central pain-modulation effect rather than a structural change — but the pain relief is real and it lets you get moving with less guarding.
Heel raise hold: Stand on both feet, rise onto your toes so your heels lift off the ground, then hold that top position. Hold for 30–45 seconds, rest 30 seconds, repeat 4–5 times. Once this is comfortable, progress to single-leg holds.
Do this daily during the acute phase, ideally before activity that would otherwise aggravate it.
Stage 2: isotonic and heavy slow resistance — building tendon capacity
Once pain has settled to a manageable baseline, the tendon needs progressive resistance. Two protocols have the strongest evidence base:
The Alfredson eccentric protocol, developed at Umeå University in Sweden, involves eccentric heel drops — rising onto your toes with both feet, then lowering slowly on the affected leg alone, letting the heel drop below the step edge. 3 sets of 15 reps, twice a day, with both a straight-knee and bent-knee variation (to load different parts of the tendon and the soleus muscle specifically), for a minimum of 12 weeks. Some discomfort during the exercise (up to 3–4 out of 10) is expected and acceptable; pain that doesn’t settle by the next morning is a sign to scale back.
Heavy slow resistance (HSR) training, from research by Jill Cook and Håkan Alfredson’s later work, has since shown comparable results using a leg press or calf raise machine with heavier external load, lower reps (6–15), and a slow 3-second lifting and lowering tempo, done 3 times a week rather than twice daily. Many patients find this more practical to fit around work and family life than the twice-daily eccentric protocol, and adherence — not the specific protocol — is usually what determines outcome.
Either approach is valid. What matters is consistency over 12 weeks minimum; most people expect faster progress and stop too early.
Stage 3: energy storage and return to sport
Walking, running and jumping all rely on the Achilles storing and releasing elastic energy — a different demand to slow, controlled loading. Before returning to running or field sport, you need to reintroduce that capacity:
Progress from double-leg to single-leg calf raises for reps, then add pogo hops (small, quick double-leg jumps focusing on a stiff ankle and short ground contact time), then single-leg hopping, before reintroducing running — starting with a run-walk protocol on flat ground rather than straight back into your previous mileage or hill sessions.
A useful marker: your affected side should manage 15–20 single-leg heel raises with reasonable symmetry to the unaffected side, and tolerate pogo hops without a pain flare the next day, before you reintroduce running.
How much pain during exercise is OK?
This is the question we’re asked most often. The working rule most physiotherapists use: pain during exercise up to 3–4 out of 10 is acceptable, it should ease within 24 hours, and morning stiffness/pain shouldn’t be getting progressively worse week on week. If pain is climbing session to session, or lingering at a high level into the next day, the load needs to come down a stage rather than being pushed through.
When exercise alone isn’t enough
Most Achilles tendinopathy responds well to a structured loading programme over 3–6 months. But a subset of patients plateau — usually those with longstanding symptoms (over 6 months), significant structural tendon changes, or a tendon that hasn’t tolerated a genuine, consistent loading trial. In that group, we’d typically recommend an ultrasound scan to look at the tendon structure directly, and consider whether shockwave therapy or an ultrasound-guided injection has a role alongside — not instead of — continued loading. Surgery is very much a last resort, reserved for the minority who don’t respond to a properly run conservative programme.
If you’re not sure whether your pain fits this pattern, or you’ve tried exercises without a clear structure and haven’t progressed, that’s exactly what a physiotherapy assessment is for — getting the loading and progression right for your specific stage, rather than guessing.
Frequently asked questions
How long does Achilles tendinopathy take to heal? Most people see meaningful improvement within 3 months of consistent, correctly-loaded exercise, with full resolution often taking 6 months or longer for longstanding cases. This is a slow-tissue-turnover condition — tendon adapts more slowly than muscle.
Should I rest completely or keep exercising? Complete rest is rarely the answer. The tendon needs load to remodel. The right approach is modifying load — reducing high-impact activity like running while continuing structured strengthening exercises — rather than stopping activity altogether.
Can I keep running with Achilles tendinopathy? Sometimes, in mild cases, with modification (reduced volume, avoiding hills and speed work, ensuring adequate recovery days). In more irritable presentations, a short period off running while you build tendon capacity through strengthening tends to get you back running sooner than pushing through.
Is it better to do eccentric exercises or heavy slow resistance? Both have strong evidence. Heavy slow resistance is often easier to stick to since it’s 3 sessions a week rather than twice daily, and adherence tends to matter more than which specific protocol you choose.
What if the pain gets worse with exercise? Some discomfort during exercise is normal and expected. Pain that worsens session to session, or is severe and lingering into the next day, means the load needs to be reduced a stage — this is a common reason people plateau, and it’s usually fixable with the right adjustment.
To get a personalised loading programme for your stage of Achilles tendinopathy, book a physiotherapy assessment at Physio & More.