Viscoelastic materials were unfamiliar and strange till now, but it is there in human bodies, it gives better understanding of our body ligaments and tendons, thank you for this video👍
Hysteresis is just a feature/phenomenon. It is the energy lost when an elastic material that has been stretched, is allowed to return to its original shape. If the path back to original does not follow the same line in the graph as the path taken when a stretch is applied, then you have a hysteresis loop, which tells you that the energy you put into the system is not the same energy that you are getting out. This means although the system can return to original shape, there is some energy loss. In tendons the hysteresis tells us that some of the energy we put in by loading the muscle (and therefore stretching the tendon) is lost through heat, leaving less energy in the tendon for movement.
