If you’ve increased your running distance, added hill sessions, or gone back into pre-season training after a quieter winter, and now have a dull, stiffening ache at the back of your heel — you’ve likely met the Achilles tendon’s least favourite thing: a sudden change in load.
Achilles tendinopathy is one of the most common overuse injuries we see this time of year, and it’s also one of the most consistently mismanaged because the instinct to “rest it until it stops hurting” is almost exactly backwards.
It’s not “tendinitis” — and that distinction matters
You’ll still hear people call this “Achilles tendinitis,” implying a straightforward inflammatory injury that settles with rest and anti-inflammatories. Current evidence describes it differently: tendinopathy is a failed healing response within the tendon structure itself, not primarily an inflammatory process. The tendon has started to change becoming disorganised at a cellular level, usually because load was increased faster than the tendon could adapt to it.
This matters clinically because it means the fix isn’t avoiding load altogether. It’s applying the right load, in the right amount, in the right progression, to stimulate the tendon to remodel and get stronger. Complete rest lets pain settle temporarily but does very little to rebuild the tendon’s capacity which is why so many people find the pain returns the moment they resume training.
What actually works: progressive tendon loading
The 2024 clinical practice guidelines from the Academy of Orthopaedic Physical Therapy reviewed the evidence across every commonly used Achilles treatment — massage, dry needling, taping, orthotics and found that exercise is the only intervention with strong (Level A) evidence. Not eccentric loading specifically, but progressive loading across all contraction types, working through stages:
- Isometric holds (holding a loaded calf raise position) — useful early on to build tolerance and can reduce pain quickly
- Slow, heavy isotonic loading (controlled calf raises with added weight) — this is where the real tendon adaptation happens, generally in the range of 70–90% of your maximum load
- Energy-storage and plyometric work (hopping, bounding) — reintroduced later, to prepare the tendon for the fast, springy demands of running and sport
Studies using this kind of staged loading program show measurable improvement in tendon pain and function within as little as two weeks, with substantial gains by the 12-week mark. It’s not a quick fix, but it is a reliable one provided the loading is progressed appropriately rather than avoided.
Common mistakes we see
- Stopping running or sport altogether and doing nothing else pain settles, capacity doesn’t rebuild, and it flares straight back up on return
- Stretching as the main treatment calf stretching alone doesn’t address the tendon’s loss of load tolerance, and aggressive stretching can aggravate some presentations
- Jumping back to full training too soon once pain settles, without having actually rebuilt strength and capacity
- Ignoring the trigger a sudden jump in running volume, hill work, or footwear change is very often the reason the tendon became reactive in the first place
Red flags — when this isn’t just tendinopathy
If you felt or heard a sudden “pop” in the back of your ankle, have significant weakness pushing up onto your toes, or notice a gap in the tendon, this could be an Achilles rupture and needs urgent assessment — please don’t wait for a routine appointment.
When to see a physio
Book in early rather than waiting to see if it settles on its own. The earlier we can assess your tendon and get an appropriately staged loading program started, the faster and more reliably it tends to resolve. This is especially true if you’re building towards a race or the start of sport pre-season.