title: Tendinopathy alters ultrasound transmission in the patellar tendon during squatting.
abstract: Measurement of loading patterns of the patellar tendon during activity is important in understanding tendon injury. We used transmission-mode ultrasonography to investigate patellar tendon loading during squatting in adults with and without tendinopathy. It was hypothesized that axial ultrasonic velocity, a surrogate measure of the elastic modulus of tendon, would be lower in tendinopathy. Ultrasound velocity was measured in both patellar tendons of adults with unilateral patellar tendinopathy (n = 9) and in healthy controls (n = 16) during a bilateral squat maneuver. Sagittal knee movement was measured simultaneously with an electrogoniometer. Statistical comparisons between healthy and injured tendons were made using two-way mixed-design ANOVAs. Axial ultrasound velocity in both symptomatic and asymptomatic patellar tendons in tendinopathy was approximately 15% higher than in healthy tendons at the commencement (F1,23= 5.2, P < 0.05) and completion (F1,23= 4.5, P < 0.05) of the squat. While peak velocity was ≈5% higher during both flexion (F1,23= 5.4, P < 0.05) and extension (F1,23= 5.3, P < 0.05) phases, there was no significant between-group difference at the midpoint of the movement. There were no significant differences in the rate and magnitude of knee movement between groups. Although further research is required, these findings suggest enhanced baseline muscle activity in patellar tendinopathy and highlight fresh avenues for its clinical management.
authors.affiliation: Institute of Health & Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia.|Division of Neurophysiology in the Center of Rare Diseases, Ulm University, Ulm, Baden-Württemberg, Germany.
authors.forename: S C
authors.initials: SC
authors.lastname: Wearing
authors.affiliation: Office of Health & Medical Research, Queensland Health, Brisbane, Queensland, Australia.
authors.forename: S L
authors.initials: SL
authors.lastname: Hooper
authors.affiliation: Institute of Health & Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia.
authors.forename: J E
authors.initials: JE
authors.lastname: Smeathers
authors.affiliation: Ecole Nationale Vétérinaire d'Alfort, Université Paris Est, Maisons-Alfort, France.|INRA, Maisons-Alfort, France.
authors.forename: P
authors.initials: P
authors.lastname: Pourcelot
authors.affiliation: Ecole Nationale Vétérinaire d'Alfort, Université Paris Est, Maisons-Alfort, France.|INRA, Maisons-Alfort, France.
authors.forename: N
authors.initials: N
authors.lastname: Crevier-Denoix
authors.affiliation: Faculty of Sports & Health Sciences, Technische Universität München, Munich, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Brauner
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D055119:Elastic Modulus / Q000502:physiology*; D006801:Humans; D017847:Patellar Ligament / Q000000981:diagnostic imaging / Q000503:physiopathology*; D052256:Tendinopathy / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014463:Ultrasonography; D016474:Weight-Bearing / Q000502:physiology*
keywords: Soft tissue; acoustic propagation; injury; quantitative ultrasound; speed of sound; tendon