The overall objective of this research program is to understand the relationships between the structural organization and mechanical function of soft connective tissues such as tendons. Knowledge of these structure-function relationships is critical for understanding the fundamental mechanisms driving normal tissue adaptation design of improved man-made composite materials (biomimetics). Therefore, the global hypothesis of this study is that tissue composition and structural organization have a significant effect on mechanical properties. An experimental model, utilizing a novel approach using genetically engineered mice, will be implemented to rigorously quantify the effect of these compositional and structural organization parameters on the tissue's mechanical properties. Testing of explicit hypotheses to evaluate these effects will be accomplished through a series of multiple regression models. In addition, a mathematical model of soft connective tissue based on realistic aspects of tissue physiology and experimentally-derived inputs, where available, will be developed and utilized to provide more insight into the problem and to assess the effect of changes in various parameters where no direct experimental input is available. Furthermore, insight gained by these analyses might be helpful in designing future experiments, or in constructing other mathematical models to investigate structure-function relationships. It is suggested that completion of the studies outlined in the current proposal will provide an improved understanding of structure-function relationships in soft connective tissues.