Properties Of Human Achilles Tendon Research Articles

New Imaging Methods for Non-invasive Assessment of Mechanical, Structural, and Biochemical Properties of Human Achilles Tendon: A Mini Review.

The mechanical properties of tendon play a fundamental role to passively transmit forces from muscle to bone, withstand sudden stretches, and act as a mechanical buffer allowing the muscle to work more efficiently. The use of non-invasive imaging methods for the assessment of human tendon's mechanical, structural, and biochemical properties in vivo is relatively young in sports medicine, clinical practice, and basic science. Non-invasive assessment of the tendon properties may enhance the diagnosis of tendon injury and the characterization of recovery treatments. While ultrasonographic imaging is the most popular tool to assess the tendon's structural and indirectly, mechanical properties, ultrasonographic elastography, and ultra-high field magnetic resonance imaging (UHF MRI) have recently emerged as potentially powerful techniques to explore tendon tissues. This paper highlights some methodological cautions associated with conventional ultrasonography and perspectives for in vivo human Achilles tendon assessment using ultrasonographic elastography and UHF MRI.

Mechanical properties of the human Achilles tendon, in vivo

Background Ultrasonography has been widely applied for in vivo measurements of tendon mechanical properties. Assessments of human Achilles tendon mechanical properties have received great interest. Achilles tendon injuries predominantly occur in the tendon region between the Achilles-soleus myotendinous junction and Achilles-calcaneus osteotendinous junction i.e. in the free Achilles tendon. However, there has been no adequate ultrasound based method for quantifying the mechanical properties of the free human Achilles tendon. This study aimed to: 1) examine the mechanical properties of the free human Achilles tendon in vivo by the use of ultrasonography and 2) assess the between-day reproducibility of these measurements. Methods Ten male subjects had the Achilles tendon moment arm length, Achilles tendon cross sectional area and free Achilles tendon length determined. All subjects performed isometric plantarflexion ramp contractions to assess between-day reproducibility on two separate days. Simultaneous ultrasonography based measurements of Achilles-soleus myotendinous junction and Achilles-calcaneus osteotendinous junction displacement together with Achilles tendon force estimates yielded free Achilles tendon mechanical properties. Findings Free Achilles tendon maximal force, deformation and stiffness were 1924 (SD 229) N, 2.2 (SD 0.6) mm and 2622 (SD 534) N/mm on day 1. For between-day reproducibility there were no significant differences between days for free Achilles tendon mechanical properties. The between-day correlation coefficient and typical error percent were 0.81 and 5.3% for maximal Achilles tendon force, 0.85 and 11.8% for maximal Achilles tendon deformation and 0.84 and 8.8% for Achilles tendon stiffness respectively. Last, osteotendinous junction proximal displacement on average contributed with 71 (SD 12) % of proximal myotendinous junction displacement. Interpretation This study, for the first time, presents an ultrasonography based in vivo method for measurement of free AT mechanical properties. The method is applicable for evaluation of free human Achilles tendon mechanical properties in relation to training, injury and rehabilitation.

The mechanical response of Achilles tendon during different kinds of sports

AbstractThe present study investigated the mechanical properties of human Achilles tendon (AT) during different forms of human locomotion, by combining biomechanical tests and numerical modelling. A Pedar‐X plantar pressure measurement system and Mega multichannel SEMG system were used to measure the dynamic data of a female athlete during hopping and walking. The human Achilles tendon force (ATF) was determined through inverse muscle force calculation. A 3D finite element (FE) model was developed using subject‐specified CT images to simulate the deformation of AT during hopping and walking. The stress/strain within the AT during different subphases (e.g. heel strike, midstance, forefoot contact, push off and toe off) was successfully predicted. Results showed that the muscle forces in hopping were much higher than in normal gait. The maximum stress in hopping was three times of that in walking. The tendon stress increased with external load over different subphases and the maximum ATF was found to be in the push‐off phase. Copyright © 2008 John Wiley & Sons, Ltd.

Elastic Properties of Human Achilles Tendon Are Correlated to Muscle Strength

Elastic Properties of Human Achilles Tendon Are Correlated to Muscle Strength

Elastic properties of human Achilles tendon are correlated to muscle strength

The purpose of this study was to investigate whether the mechanical properties of the Achilles tendon were correlated to muscle strength in the triceps surae in humans. Twenty-four men and twelve women exerted maximal voluntary isometric plantar flexion (MVIP) torque. The elongation (DeltaX) and strain of the Achilles tendon (epsilon), the proximal part of which is the composite of the gastrocnemius tendon and the soleus aponeurosis, at MVIP were determined from the displacement of the distal myotendinous junction of the medial gastrocnemius using ultrasonography. The Achilles tendon force at MVIP (F) was calculated from the MVIP torque and the Achilles tendon moment arm. There were no significant differences in either the F-DeltaX or F-epsilon relationships between men and women. DeltaX and epsilon were 9.8 +/- 2.6 mm and 5.3 +/- 1.6%, respectively, and were positively correlated to F (r = 0.39, P < 0.05; r = 0.39, P < 0.05), which meant that subjects with greater muscle strength could store more elastic energy in the tendon. The regression y-intercepts for the F-DeltaX (P < 0.01) and F-epsilon (P < 0.05) relationship were significantly positive. These results might indicate that the Achilles tendon was stiffer in subjects with greater muscle strength, which may play a role in reducing the probability of tendon strain injuries. It was suggested that the Achilles tendon of subjects with greater muscle strength did not impair the potential for storing elastic energy in tendons and may be able to deliver the greater force supplied from a stronger muscle more efficiently. Furthermore, the difference in the Achilles tendon mechanical properties between men and women seemed to be correlated to the difference in muscle strength rather than gender.