Muscles are covered with a sheath of connective tissue (fascia) that helps them glide over surrounding tissues. This tissue can loose its pliability and stick to adjacent muscles, bones or ligaments. Fascia also covers and separates most tissues in the body. The specific fascia that covers muscles is referred to as myofascial tissue.
Fascia is continually being created. Without proper movement the facial fibers will cross link and and restrict movement or bind muscles and nerves creating pain. After injuries this is especially true when large amount of fascia are formed as scar tissue. These adhesions bind muscles to other tissues including other muscles, nerves, bones and more. They inhibit the muscles from moving properly. If nerves are adhered they are not free to slide past other tissues when they move or can become restricted.
These adhesions must be released using precise techniques and will not respond to powerful stretches or deep tissue work.
Fascia responds to a gentle differential stretch but when you exceed the proper tension it does not release no matter how long you hold the tension. It appears under light force (shear) to be thixotropic (more fluid over time, under shear). You have to use just enough stretch to engage it but with more, it behaves like a dilantantic substance (like corn starch and water or silly putty) which is less fluid under sheer. Most thixotrops will liquefy even more when the shear force or time increases. It seems that fascia deforms under low shear but resists high sheer.
The gel like fluid between the fibers called "ground substance" is thixotropic and the collagen fibers are dilantantic so that to stretch the fascia you need enough force to get it to move but not so much that the collagen fibers lock. This is why you are able to break the weaker cross links and get more mobility yet the normal collagen fibers prevent more vigorous stretching from breaking the cross links.
Scar tissue is fascia with fibers that go every which way. Breaking
some of the fibers except those that are aligned in a useful direction
converts the scar tissue to normal fascia. In actuality you will never
get perfectly aligned fibers but we can add more flexibility to scars tissue
and remove adhesions to surrounding tissues.
Using subtle but precise tension for myofascial release, relies on the body's own natural wisdom to determine the proper course of action. The fascia comprise of a complex interconnected web within your body to support and protect soft tissues. If the therapist attempts a release that is not right, the release will not happen or the tension will reappear. Sometimes we have to do things in a specific order that may be different from the normal order because the body to protecting an injury and problem.
There are also some moves that use the thixotropic properties of the ground substance. Sharp, quick almost explosive stretches will transfer tension from healthy tissue to scar tissue can cause the weaker scar tissue to shear. This is also done using quickness rather than force to prevent problems of over extending joints or stressing healthy tissues.