What is muscle elasticity? If you were to stretch a muscle you would see it shrink back a bit. In plain words, it’s a natural ability to recover to original form upon the removal of the force initially applied. In physical activity it is the ability of muscles to perform work, specifically, to contract rapidly after and immediately prior to extension. A human body is a mix of physics, geometry, psychology and all that good stuff, so we should not talk about muscles and their function as separate from the whole.