You’ve just put in a great block of training. Now your knee hurts. Does that mean you’re injured? Well… it’s complicated, according to a new opinion piece in the British Journal of Sports Medicine. Athletes are constantly dealing with pains and niggles, some that disappear and others that persist. Judging which ones to ignore and which ones to take seriously is a delicate art—and how we choose to label those pains, it turns out, can affect the outcome.
The new article is by Morten Høgh, a physiotherapist and pain scientist at Aalborg University in Denmark, along with colleagues from Denmark, Australia, and the United States. It argues that, in the context of sports medicine, pain and injury are two distinct entities and shouldn’t be lumped together. When pain is inappropriately labeled as an injury, Høgh and his colleagues argue, it creates fear and anxiety and may even change how you move the affected part of the body, which can create further problems.
To start, some definitions: A sports-related injury refers to damage to some part of the body. It’s usually indicated by physical impairment, an identifiable mechanism of injury, and perhaps signs of inflammation. If you tear your ACL, there’s no doubt that you’re injured. One important caveat: If you look hard enough, you’ll often find something that looks like an injury. Take X-rays of a middle-aged athlete with knee pain, and you may see signs of cartilage degeneration in the bad knee—but you might also see the same thing in the good knee, too. That’s a common consequence of aging, and it doesn’t explain why the bad knee is hurting.
Pain, on the other hand, is defined in the paper as “an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage.” The italics are mine. It certainly feels like something is damaged. But pain is fundamentally a subjective, patient-reported phenomenon, and it can exist even without an identifiable injury. One of the examples in the paper is patellofemoral pain, which is a very common diagnosis in runners that basically means your knee hurts but they can’t figure out exactly why it’s hurting. In comparison, patella tendinopathy is knee pain with a clinically identifiable cause for the pain (a damaged or inflamed tendon).
The paper includes an infographic (viewable here) that outlines the differences between what they call “sports-related injuries” and “sports-related pain.” Here are some of the key points:
- Pain is influenced by “context, expectations, beliefs, and cognitions”; injuries aren’t. As it happens, the New York Times ran an article just last week on how words like “burning” and “stabbing” affect how you feel pain. My favorite nugget from that story: the patient in Australia who returned to her native Nepal for treatment because no one understood her description of “kat-kat,” an untranslatable expression of achiness that can feel deeply cold.
- Injuries are objectively observable; pain isn’t. That said, subjective assessments of pain, including a simple zero to ten rating, can be remarkably repeatable and informative. That’s how we know that effort, not pain, is what causes people to give up in tests of cycling endurance.
- The prognosis for an injury will depend on which body part is affected: injured muscles heal better than, say, spinal disks, and the healing will proceed in predictable stages. Pain, in contrast, often comes and goes unpredictably, and its severity doesn’t necessarily depend on the healing stage.
- The fundamental principle of rehab from injury is gradually increasing the load on the damaged tissue until healing is complete and it’s capable of handling the demands of training and competition. The focus for sports-related pain is improving the patient’s ability to manage the pain, for example by avoiding negative responses like pain catastrophizing that make it feel worse. This process isn’t as linear as rehabbing damaged tissue: you can’t just gradually increase training load and assume that pain will go away.
The themes in Høgh’s paper overlap with another recent British Journal of Sports Medicine editorial, this one from Australian physician Daniel Friedman and his colleagues, on the dangers of diagnostic labels. Calling a knee injury a meniscal tear rather than a meniscal strain, for example, might nudge the patient toward opting for arthroscopic surgery, even though that’s not considered the best approach to that injury. More generally, Friedman writes, the words chosen to describe injuries “may catalyze a looping effect of catastrophization, anxiety, and fear of movement.”
In many cases, of course, these nuances aren’t a big deal. If you get a stress fracture, it will hurt. You’ll have to rest it until it heals, gradually increase the load on it, and then pain should no longer be an issue. The injury and its associated pain are tightly coupled. But other cases aren’t so straightforward. For people with chronic Achilles pain, there’s often no clear link between the physical state of the tendon and how it feels, so reducing and managing pain sufficiently to return to training is a more useful goal than waiting for the tendon to be “healed.” Figuring out where any given flare-up falls on that spectrum is tricky, but the first step, according to Høgh, is simply recognizing that sometimes pain is just pain.
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