Mechanische Kenngrößen von biologischem Weichgewebe - Mechanical Characteristics of Biological Soft Tissue

Abstract

In a detailed study mechanical properties of tendons, muscles, nerves, blood-vessels and skin of just slaughtered pigs have been investigated in nearly stationary stress tests. Tensile tests have produced tensile strength, ultimate stress and their appropriate strains, Young's modulus and the work up to fatigue of samples. In hysteresis tests the deformation work has been determined as a function of numbers of stress cycles. The hysteresis decrease with the number of stress cycles and approaches asymptotically to cero. By preconditioning of tendons, nerves and blood-vessels to steady state significant differences of strain at tensile strength and of Young's modulus have been established. Moreover for nerves the tests have revealed significant deviations of tensile strength. Bruise tests have been carried out with muscle tissue. For the described setup the limit force can be specified, at which pathological changes appear. Subsequently conducted histological investigations have demonstrated this. In dynamical bruise tests there appeared no pathological changes in muscle tissue in spite of higher transmitted energy.

Effect of cyclic preconditioning on the tensile properties of human quadriceps tendons and patellar ligaments

“…During cyclic preconditioning, fluid squeezed out of the tendons and ligaments, producing a fluid drop which accumulated at the lower end of the test specimen. Fluid loss was also observed by several authors previously [6,8,22]. We speculate that alterations of proteoglycans and hyaluronic acid concentrations affect the viscoelastic properties by an alteration of hydrogen and salt-like bonds between the matrix and fibrillar structure [22].…”

“…In the literature we did not find any studies examining the influence of preconditioning on the tensile properties of quadriceps tendons so far. Studies with other preconditioned tendons or ligaments are not comparable to this study because of different specimen complexes and testing protocols at much lower preconditioning loads [5,6,8,9,20]. Previously published studies confirm that preconditioning is essential for assessing the viscoelastic properties of soft connective tissues.…”