Quasi-static and cyclic uniaxial mechanical loading exhibit distinct influences on the biomechanical properties of engineered scaffold-free tendon fibers

Herein, a novel, scaffold-free fiber engineering platform was utilized to investigate the influence of quasi-static and dynamic uniaxial loading on tendon fiber development. Engineered fibers were subjected to 3 days of basic loading (i.e., intermittent cyclic uniaxial strain) or combined loading (i.e., basic loading plus an incremental quasi-static component). After 3 days, the basic loading increased fiber elastic modulus and failure stress, but did not affect failure strain, as compared to unloaded controls. The addition of a quasi-static component did not further affect modulus or failure stress, but caused a significant increase in toe-in and failure strains, compared to basic loading alone. These findings suggest distinct biomechanical roles for dynamic and quasi-static loading in tendon development.