Stress relaxation and recovery in tendon and ligament: Experiment and modeling

Duenwald, Sarah E.; Vanderby, Ray; Lakes, Roderic S.

doi:10.3233/bir-2010-0559

Cited by 65 publications

(46 citation statements)

References 24 publications

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“…To perform in this manner, tendons have complex mechanical behavior that exhibits viscoelasticity, nonlinearity and anisotropy. 8, 14, 31, 34, 38 This behavior is modulated by the structure and composition of the tissue, which can vary widely between (Achilles versus patellar) and within tendons (insertion versus midsubstance). 8, 12, 13, 16 Generally, tendon is made primarily of a hierarchical collagen structure, with collagen fibrils that bundle to form fibers which bundle to form tendon.…”

Section: Introductionmentioning

confidence: 99%

Diabetes Alters Mechanical Properties and Collagen Fiber Re-Alignment in Multiple Mouse Tendons

et al. 2014

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Tendons function to transfer load from muscle to bone through their complex composition and hierarchical structure, consisting mainly of type I collagen. Recent evidence suggests that type II diabetes may cause alterations in collagen structure, such as irregular fibril morphology and density, which could play a role in the mechanical function of tendons. Using the db/db mouse model of type II diabetes, the diabetic skin was found to have impaired biomechanical properties when compared to the non-diabetic group. The purpose of this study was to assess the effect of diabetes on biomechanics, collagen fiber re-alignment, and biochemistry in three functionally different tendons (Achilles, supraspinatus, patellar) using the db/db mouse model. Results showed that cross-sectional area and stiffness, but not modulus, were significantly reduced in all three tendons. However, the tendon response to load (transition strain, collagen fiber re-alignment) occurred earlier in the mechanical test, contrary to expectations. In addition, the patellar tendon had an altered response to diabetes when compared to the other two tendons, with no changes in fiber realignment and decreased collagen content at the midsubstance of the tendon. Overall, type II diabetes alters tendon mechanical properties and the dynamic response to load.

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Section: Introductionmentioning

confidence: 99%

Diabetes Alters Mechanical Properties and Collagen Fiber Re-Alignment in Multiple Mouse Tendons

et al. 2014

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“…For example, the wave theory equations utilized in elastography are not strain dependent, and therefore it uses only an initial and end state for analysis. This precludes it from defining the strain-dependent viscoelastic behavior previously demonstrated in tendon [23,24] unless by linear increments. Furthermore, to avoid errors arising from tissue strain dependence, elastography experiments in soft tissues are traditionally limited to very small (<1% strain) strains; when soft tissues were tested under larger deformations and were therefore nonlinear in stiffness, significant errors occurred [30,31].…”

Section: Discussionmentioning

confidence: 99%

“…The proximal end of the tendon was cleaned of all muscle tissue and the cross-sectional area (assumed elliptical) was measured using calipers at three points along the length of the tendon and averaged. Specimens were then loaded into the mechanical test system (MTS Bionix, Minneapolis, MN) equipped with a bath filled with physiologic buffered saline (which served to both keep the tendon hydrated and transmit ultrasound waves), a 1000 lb load cell (Honeywell, Morristown, NJ), and custom-made grips [23], preloaded to 1N, and preconditioned for 20s at 0.5Hz using a sinusoidal wave to 2% strain (using grip-to-grip displacement and initial length measurements), followed by a 1000 s rest period.…”

Section: Methodsmentioning

confidence: 99%

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Time-Dependent Ultrasound Echo Changes Occur in Tendon During Viscoelastic Testing

Duenwald-Kuehl

Kobayashi

Lakes

et al. 2012

Journal of Biomechanical Engineering

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The viscoelastic behavior of tendons has been extensively studied in vitro. A noninvasive method by which to acquire mechanical data would be highly beneficial, as it could lead to the collection of viscoelastic data in vivo. Our lab has previously presented acoustoelasticity as an alternative ultrasound-based method of measuring tendon stress and strain by reporting a relationship between ultrasonic echo intensity (B mode ultrasound image brightness) and mechanical behavior of tendon under pseudoelastic in vitro conditions [Duenwald, S., Kobayashi, H., Frisch, K., Lakes, R., and Vanderby Jr, R., 2011, “Ultrasound Echo is Related to Stress and Strain in Tendon,” J. Biomech., 44(3), pp. 424–429]. Viscoelastic properties of the tendons were not examined in that study, so the presence of time-dependent echo intensity changes has not been verified. In this study, porcine flexor tendons were subjected to relaxation and cyclic testing while ultrasonic echo response was recorded. We report that time- and strain history-dependent mechanical properties during viscoelastic testing are manifested in ultrasonic echo intensity changes. We also report that the patterns of the echo intensity changes do not directly mimic the patterns of viscoelastic load changes, but the intensity changed in a repeatable (and therefore predictable) fashion. Although mechanisms need further elucidation, viscoelastic behavior can be anticipated from echo intensity changes. This phenomenon could potentially lead to a more extensive characterization of in vivo tissue behavior.

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“…Though nonlinear viscoelasticity frameworks such as that of Schapery (1969) are used in biomechanics (Provenzano et al, 2002; Duenwald et al, 2010), they have not been adopted widely possibly because existing formulations remain complex. Nonlinear elasticity formulations broadly follow the elegant framework of Coleman and Noll (1963), where the stress response is derived from a free energy potential expressed as a function of the deformation gradient.…”

Section: Introductionmentioning

confidence: 99%

Viscoelasticity using reactive constrained solid mixtures

Ateshian

2015

Journal of Biomechanics

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This study presents a framework for viscoelasticity where the free energy density depends on the stored energy of intact strong and weak bonds, where weak bonds break and reform in response to loading. The stress is evaluated by differentiating the free energy density with respect to the deformation gradient, similar to the conventional approach for hyperelasticity. The breaking and reformation of weak bonds is treated as a reaction governed by the axiom of mass balance, where the constitutive relation for the mass supply governs the bond kinetics. The evolving mass contents of these weak bonds serve as observable state variables. Weak bonds reform in an energy-free and stress-free state, therefore their reference configuration is given by the current configuration at the time of their reformation. A principal advantage of this formulation is the availability of a strain energy density function that depends only on observable state variables, also allowing for a separation of the contributions of strong and weak bonds. The Clausius-Duhem inequality is satisfied by requiring that the net free energy from all breaking bonds must be decreasing at all times. In the limit of infinitesimal strains, linear stress-strain responses and first-order kinetics for breaking and reforming of weak bonds, the reactive framework reduces exactly to classical linear viscoelasticity. For large strains, the reactive and classical quasilinear viscoelasticity theories produce different equations, though responses to standard loading configurations behave similarly. This formulation complements existing tools for modeling the nonlinear viscoelastic response of biological soft tissues under large deformations.

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Stress relaxation and recovery in tendon and ligament: Experiment and modeling

Cited by 65 publications

References 24 publications

Diabetes Alters Mechanical Properties and Collagen Fiber Re-Alignment in Multiple Mouse Tendons

Diabetes Alters Mechanical Properties and Collagen Fiber Re-Alignment in Multiple Mouse Tendons

Time-Dependent Ultrasound Echo Changes Occur in Tendon During Viscoelastic Testing

Viscoelasticity using reactive constrained solid mixtures

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