Comparison of mechanical properties of XXXX tibialis anterior tendon evaluated using two different approaches.

@entity19 @entity924 @entity1796 @entity35
@entity1796 may result in variations of its mechanical properties. The published data of the @entity924 of small animals, such as @entity19 and @entity35 , are exclusively obtained by measuring grip-to-grip (g-t-g) displacement. Local strain concentration and relative sliding of the specimens in the clamps might significantly affect the measured tendon deformation. In the present study, the mechanical properties of the @entity35 tibialis anterior tendon measured using the proposed tendon mark method were compared to those evaluated using the g-t-g displacement method. Five male @entity35 ( approximately 418 g) were used in this study. For the proposed method, reference marks were made on the tendons using permanent ink. A microscope video system was customized to observe and record the tendon deformation. Pattern recognition software was developed to obtain the displacement time-histories of the reference marks. The distance between the grips was approximately 7 mm; and the distance between the reference marks used for the data processing was approximately 5 mm. The cross-section areas of the specimens were measured using a custom-made slot gauge and by applying a constant compressive stress (0.15 MPa). The tendons were clamped between two custom-made metal grips and stretched on a testing machine at a constant speed (1 mm/s) up to failure. Throughout the tests, the tendon specimens were submerged in a PBS bath at 22 degrees C. The deformation of the specimens was evaluated using the g-t-g displacement method and the proposed method. The stress/strain curves obtained by using the g-t-g displacement can be characterized by an initial toe zone, a quasi-linear zone, and a final failure stage. The stress/strain curves determined using the proposed method are quite different from those obtained using the g-t-g displacement: it has a smaller toe zone and a stress-hardening transition, over which the @entity924 increases dramatically with the increasing strain. The @entity924 measured by using the g-t-g displacement method may underestimate the actual mechanical properties of tendon by approximately 43%.
