Related Experiment Video
Updated: Feb 12, 2026
Ultrasound Tissue Characterization of Human Achilles Tendon by Stability Quantification of Echo Patterns
Published on: September 5, 2025
Clinical Improvements Are Not Explained by Changes in Tendon Structure on Ultrasound Tissue Characterization After an
Mathijs van Ark1, Ebonie Rio, Jill Cook
1From the Department of Sport and Exercise Medicine, University Medical Center Groningen, University of Groningen, the Netherlands (MvA, IvdA-S, JZ); School of Physiotherapy, Monash University, Frankston, Australia (MvA, ER, JC, SD); Department of Physiotherapy, Hanze University of Applied Sciences Groningen, the Netherlands (MvA); Centre of Expertise Primary Care Groningen (ECEZG), the Netherlands (MvA); La Trobe University Sport and Exercise Medicine Research Centre. Bundoora, Australia (ER, JC, SD); Australian Collaboration for Research into Sports Injury and Its Prevention (ACRISP), Federation University, Ballarat, Australia (ER, SD); and University of Canberra Research Institute for Sport and Exercise (UCRISE), Australia (JEG).
Objectives:
The aim of this study was to investigate the effects of a 4-wk in-season exercise program of isometric or isotonic exercises on tendon structure and dimensions as quantified by ultrasound tissue characterization (UTC).
Design:
This was a randomized clinical trial. Volleyball and basketball players (16-31 yrs, n = 29) with clinically diagnosed patellar tendinopathy were randomized to a 4-wk isometric or isotonic exercise program. The programs were designed to decrease patellar tendon pain. A baseline and 4-wk UTC scan was used to evaluate change in tendon structure.
Results:
No significant change in tendon structure or dimensions on UTC was detected after the exercise program despite patellar tendinopathy symptoms improving. The percentage and mean cross-sectional area of aligned fibrillar structure (echo types I + II) (Z = -0.414, P = 0.679) as well as disorganized structure (echo types III + IV) (Z = -0.370, P = 0.711) did not change over the 4-wk exercise program. Change in tendon structure and dimensions on UTC did not differ significantly between the groups.
Conclusion:
Structural properties and dimensions of the patellar tendon on UTC did not change after a 4-wk isometric or isotonic exercise program for athletes with patellar tendinopathy in-season, despite an improvement in symptoms. It seems that structural improvements are not required for a positive clinical outcome.
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