Ultrasonic evaluations of Achilles tendon mechanical properties poststroke

Heng Zhao, Yupeng Ren, Yi Ning Wu, Shu Q. Liu, Li Qun Zhang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

91 Scopus citations


Spasticity, contracture, and muscle weakness are commonly observed poststroke in muscles crossing the ankle. However, it is not clear how biomechanical properties of the Achilles tendon change poststroke, which may affect functions of the impaired muscles directly. Biomechanical properties of the Achilles tendon, including the length and cross-sectional area, in the impaired and unimpaired sides of 10 hemiparetic stroke survivors were evaluated using ultrasonography. Elongation of the Achilles tendon during controlled isometric ramp-and-hold and ramping up then down contractions was determined using a blockmatching method. Biomechanical changes in stiffness, Young's modulus, and hysteresis of the Achilles tendon poststroke were investigated by comparing the impaired and unimpaired sides of the 10 patients. The impaired side showed increased tendon length (6%; P = 0.04), decreased stiffness (43%; P < 0.001), decreased Young's modulus (38%; P = 0.005), and increased mechanical hysteresis (1.9 times higher; P < 0.001) compared with the unimpaired side, suggesting Achilles tendon adaptations to muscle spasticity, contracture, and/or disuse poststroke. In vivo quantitative characterizations of the tendon biomechanical properties may help us better understand changes of the calf muscle-tendon unit as a whole and facilitate development of more effective treatments.

Original languageEnglish (US)
Pages (from-to)843-849
Number of pages7
JournalJournal of applied physiology
Issue number3
StatePublished - Mar 2009


  • Mechanical property
  • Muscle
  • Stroke
  • Ultrasound

ASJC Scopus subject areas

  • Medicine(all)


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