“Tendonitis” is the word everyone uses, and it smuggles in a wrong idea. The suffix implies inflammation, which implies the treatment: rest it, ice it, take anti-inflammatories, wait. For an acute, fresh tendon irritation that advice is partly right. But for the tendon pain that lingers for months, the Achilles that will not settle, the tennis elbow, the painful shoulder tendon, researchers who have examined these tendons find remarkably little inflammation. They find a tendon whose internal structure has changed under load it could not handle. The modern name is tendinopathy, and the name change matters, because a changed tendon needs rebuilding, not just calming.
The continuum model
The framework clinicians use comes from Cook and Purdam’s widely cited 2009 paper in the British Journal of Sports Medicine. Tendon pathology, they proposed, runs along a continuum with three stages:
- Reactive tendinopathy: a short-term response to a sudden load spike, the tendon thickens and stiffens defensively. Young, sudden-onset, and reversible if the load is managed.
- Tendon dysrepair: the failed-healing middle ground, where the tendon tries to repair but its structure becomes more disorganised.
- Degenerative tendinopathy: areas of the tendon with advanced structural change, common in older, long-standing cases, often with a reactive flare sitting on top of them, which is the painful part being treated.
The clinical payoff: the stage dictates the strategy. A reactive tendon needs load management and calm; a degenerative one needs its still-healthy tissue strengthened, patiently, without provoking the reactive portion. One-size exercise sheets fail because the same exercise is medicine for one stage and provocation for another.
The treatment pattern that works
- Load management first: identify the loads that flare it, usually a specific combination of compression, speed, and volume, and trim those, not all activity
- Isometrics early: sustained static contractions often give genuine pain relief in irritable tendons and keep the muscle working
- Progressive heavy loading: slow, heavy resistance training, progressed over roughly twelve weeks, is the core intervention across most tendinopathies, the tendon adapts to what it is repeatedly asked to do
- Energy storage last: spring-like work, hopping, plyometrics, sport-speed loads, only when strength is rebuilt, because that is the tendon’s most demanding job
- The 24-hour rule: some discomfort during loading is acceptable if symptoms return to baseline by the next morning; still worse at 24 hours means the dose overshot
What about injections and rest?
Complete rest deconditions tendon and muscle, and the pain reliably returns on re-loading, the tendon is now weaker than when you started. Corticosteroid injections can relieve pain briefly in some tendinopathies but repeatedly show poorer long-term outcomes (the JAMA trial in the elbow article is the cleanest example). They are a tool for specific situations, not a foundation. The foundation is progressive load, unglamorous, slow, and the intervention with the evidence.
Timelines
Tendons remodel slowly because their blood supply is poor. Three months is a typical minimum for meaningful change; long-standing degenerative cases run longer. The trajectory matters more than any single week: morning stiffness easing, load tolerance rising, the good days stringing together.
References
- Cook JL, Purdam CR. Is tendon pathology a continuum? A pathology model to explain the clinical presentation of load-induced tendinopathy. British Journal of Sports Medicine. 2009;43:409–416. doi:10.1136/bjsm.2008.051193
- Martin RL, Chimenti R, Cuddeford T, et al. Achilles Pain, Stiffness, and Muscle Power Deficits: Midportion Achilles Tendinopathy Revision 2018. Journal of Orthopaedic & Sports Physical Therapy. 2018;48(5):A1–A38. doi:10.2519/jospt.2018.0302
General information only, not medical advice. A tendon that snapped, or pain after a distinct injury, needs prompt in-person assessment.