Biomechanics Terminology: Elastic & Plastic Deformation, Elastic Modulus and Elastic Strain Energy In this 16-minute mini-lecture, I describe the concepts of elastic and plastic deformation of materials, with special emphasis on how elastic deformation prevents injury to our body's structural tissues, while plastic deformation of our body's tissues is the cause of tissue injuries such as partial tears and complete ruptures of tendon, ligament and fascia, cartilage tears, stress reactions and str