Mechanical testing of tendons and ligaments (360G-Wellcome-207265_Z_17_Z)

The mechanism for collagenous connective tissue damage is little understood. The micromechanics of collagenous tissues is important to understand as it may contribute to injury prevention and be useful in designing treatments for pre existing tissue damage. Bontempi et al in 2009 theorised a relationship between the the probability density function of the stretch value of individual fibrils and the 2nd derivative of stress with stretch. This relationship gained experimental backing in 2016. Recent research suggests that fibrils fail in the order they are first recruited. Combining this model with Bontempi's work suggests fibrillar level damage can be found by performing a stress - stretch test in vivo. However the relationship between order of recruitement and failure is yet to be experimentally proven. A collagen fibril is considered recruited once it is straight enough to bear load and be treated as a Hookean material. During my research I will be tracking fibrils from point of first recruitment to failure. A tensile loading rig will be used with a microscope to image the tendons at different stretch levels.