Achilles tendons from male F344xBN rats at 1, 8, 19, and 28 months of age were harvested and evaluated for their multiscale properties via high frequency ultrasound (1), nanoindentation (2), tensile mechanical testing (3), and histomorphometric analysis (4). Using microscale properties determined from tendon samples, alginate-based hydrogels were engineered with similar properties to examine the effects of stiffness and viscoelasticity on tendon derived cells during aging.