Your tendon can feel better without looking better on a scan

Loaded exercise, working a painful tendon against resistance, is a mainstay treatment for tendinopathy, and previous reviews confirm it helps. The assumption behind much of that practice has been that loading stimulates the tendon to remodel: collagen realigns, the matrix repairs, and pain settles because the tissue heals. If that story were true, structural change on imaging should track with clinical improvement. This review set out to test whether it actually does.

The authors searched six databases from their inception to June 2012 for any study that measured both observable structural outcomes and clinical outcomes in people with tendinopathy treated with therapeutic exercise. Twenty articles describing 625 patients met the criteria. Risk of bias was appraised with an established tool, and because the studies differed too much in design to combine statistically, the evidence was synthesised qualitatively. The central question was whether structural change explained the clinical response to exercise.

For eccentric exercise training, the most widely prescribed approach, there was strong evidence refuting observable structural change as the explanation for why patients improve. In other words, tendons became less painful and more functional without reliably looking different. The one partial exception was heavy-slow resistance training, where moderate evidence supported a structural response. The authors concluded the mechanism remains unexplained and pointed to neural, biochemical and myogenic changes as candidates for future research.

This complicates a tidy narrative that rehabilitation works by rebuilding tissue, and it aligns tendon research with a broader theme in musculoskeletal science: symptoms and scans often tell different stories. It does not question whether loaded exercise helps, only why it helps. Open questions include what heavy-slow resistance training is doing differently, and whether changes in the nervous system or in tendon biochemistry drive the improvements patients feel.

If you are rehabbing an Achilles, patellar or elbow tendon, this is a reason not to be discouraged by an unchanged scan, and equally not to wait for imaging to look normal before trusting your progress. Pain and function improved independently of visible structure in these studies. It also suggests that a scary-looking ultrasound is not necessarily the final word on how a tendon will respond to sensible loading.