Why it still hurts long after the injury should have healed

Nine months ago you strained something. It healed, by any reasonable definition of healed. You have done the exercises. The scan was unremarkable, or remarkable in ways nobody seemed worried about. And the run this morning still hurt at kilometre four, the way it has since spring.

This is a different problem from a fresh injury, and it needs a different set of questions. The useful one is not what is torn. It is why the pain is still being produced.

How common the long version is

A third is a large minority. It is large enough that a rehab plan which assumes everyone is fine by week twelve will mislabel a lot of normal recoveries as failures.

The same cohort found something runners rarely expect. Runners who had been covering more weekly distance before the problem started were less likely to still have symptoms a year later, not more¹. Being a bigger runner before an injury was protective.

Pain is produced, not measured

The most useful idea in this whole area is also the least intuitive. Pain is not a readout from the tissue. It is produced by the nervous system, and how much of it you get is only loosely tied to what is happening in the leg.

Nociception, the signalling from the periphery, is one input among several³. That is why the same tendon can be quiet on a Tuesday and loud on a Saturday with no change in the tendon, and why two runners with similar findings can be in very different amounts of trouble.

Why pain can outlast the healing

Repeated signalling from the periphery changes how efficiently the spinal cord passes those signals on. The umbrella term is central sensitization, and the effects can outlast the original stimulus by hours, days or longer⁴. It is a credible explanation for why pain persists after an injury has healed, and it is one of the better things pain science has given clinicians.

It is also routinely oversold.

What you can observe is how your pain behaves when the load changes. That is not a diagnosis, and the two columns below overlap in real people. It does tell you where to spend the next month.

Tracks the loadHas its own weather

Response to a lighter week

Tracks the loadSettles noticeably within a week or two.

Has its own weatherBarely changes, or changes for reasons you cannot tie to training.

Location

Tracks the loadStays in the same structure.

Has its own weatherSpreads, moves, or shows up on the other side.

Provocation

Tracks the loadPredictable. The same run produces roughly the same pain.

Has its own weatherVaries day to day, and tracks sleep, stress or a bad week at work more than mileage.

Between sessions

Tracks the loadQuiet when you are not loading it.

Has its own weatherPresent at rest, in bed, or first thing in the morning.

What a scan actually tells you

Runners are often told that findings on a scan mean nothing, because plenty of pain-free people have them. The first half is an overcorrection, and the evidence is more interesting than that.

So the finding is not noise. What it is not is an explanation for today's pain. It is a marker of a tendon that is more likely to become symptomatic at some point, in a population, over time. It says nothing about why this run hurt, and nothing about whether the pain will settle. Those studies were in tendons, mostly in sporting populations, and the same logic does not automatically carry to a knee or a back.

Does understanding your pain help?

Explaining pain biology to people in pain, usually called pain neuroscience education, has become a standard part of rehab. It works, modestly, and it works better as part of something than on its own.

That matches what we see. Understanding why a tendon behaves the way it does makes the next twelve weeks tolerable, which is what lets the loading actually happen. It is a multiplier on the training, not a replacement for it.

The part most rehab plans skip

If a runner's rehab has stalled and the loading looks sensible, sleep is the first place we look.

These are population associations rather than proof that fixing your sleep fixes your Achilles. But the direction is consistent, the effect is not small, and the thing being asked of you is reasonable regardless.

What does not predict a bad outcome

Runners with long-standing pain often arrive having been told, in one form or another, that their attitude is the problem. It is worth knowing how weak the evidence for that is.

This was one tendon, one diagnosis, 24 weeks, and a relatively homogeneous group, so it does not settle the question for every persistent pain problem. It does mean that in the condition runners most often have, how you cope was not what separated the people who got better from the people who did not.

When it needs looking at

Persistent pain is not a reason to accept a vague answer. It is a reason to want a specific one: which tissue, what load it currently tolerates, what would have to change for it to tolerate more, and roughly how long that takes.