Bi-lateral Mechanical Properties of the Achilles Tendon

Open Access
Howse, Brittany Noelle
Graduate Program:
Master of Science
Document Type:
Master Thesis
Date of Defense:
July 26, 2012
Committee Members:
  • John Henry Challis, Thesis Advisor
  • Achilles
  • tendon properties
  • ultrasound
  • asymmetry
The Achilles tendon is responsible for transmitting forces from the triceps surae complex to the calcaneus, enabling plantar-flexion of the ankle which ultimately allows for locomotion. As the thickest tendon in the human body combined with its superficial placement near the skin, the Achilles tendon is a superior subject for ultrasound examination. This study aimed to examine the bi-lateral mechanical and anthropometric properties of the Achilles tendon, specifically comparing the dominant and non-dominant leg across both male and female subjects. Achilles tendon length, tendon volume, peak strain, and maximum ankle plantar-flexion moment were measured on ten male and ten female subjects. Data showed asymmetry to all metrics analyzed. The twenty subjects exhibited an average asymmetry between dominant and non-dominant legs of 12.1% for maximum ankle plantar-flexion moment, 4.6% for Achilles tendon length, 10.8% for Achilles tendon volume, and 22.4% for Achilles tendon peak strain; however none of these differences were statistically significant. Significant differences were reported, however, in comparisons across the sexes. Males exhibited significantly larger normalized maximum ankle plantar-flexion moments than females, in addition to significantly larger Achilles tendon strain on the non-dominant leg. Females also exhibited significantly greater levels of asymmetry than men for normalized maximum ankle plantar-flexion moment values, and Achilles tendon length. This study is the first to report data assessing the symmetry between the limbs for Achilles tendon mechanical properties; it provides a point of reference for the natural variability of the Achilles tendon.