When the collagen fibers within the connective tissues are healthy they generally line up quite straight, and along the direction of the predominant stress. The top image here indicates this in a simple graphical way. Shown are the major parallel lines of collagen fibers in a tendon.


As the body ages or is damaged, these relatively straight fibers become tangled or bent and as a result they are shorter, drawing the muscle and the bone closer together and decreasing the range of movement possible. The bottom image shows how this shortening occurs. Notice also that within the tangled area of the fibers, particles can become trapped. When the fibers are long and straight there is less likelihood of particles being trapped inside the fiber. What is trapped can be toxic to the body – waste products from the metabolism of nearby cells or particles of pollution from outside the body, like smoke or pesticides.


Once these particles are trapped they can remain in the body for a long time, even forever. Massage and yoga, which move the tissues of the body, can loosen up the bonds that trap these particles. Once freed, the particles can be swept into the blood system or lymphatic system and carried away, eventually eliminated from the body. It has long been known in the East that yoga is a detoxifying practice; understanding how the body works helps us to understand why this is so. Yoga stretches and compresses the collagen network of the body, which lengthens fibers and frees toxic particles – just like we do to that old, gnarly sponge we all have hiding under our kitchen sink.

The graphics above are meant to illustrate the principle of how collagen fibers can become matted and shortened. The images to the right are actual microscopic pictures of collagen fibers that have been damaged and are on their way to healing.

The images come from a study by Frank and Shriver on how collagen tissues grow and heal over time the two images on the top are initially traumatized tissues. The researchers looked at the tissue as it healed. The bottom images are the tissues after 11 days. It is obvious that the fibers have aligned and straightened. It is not as obvious as in the artist’s concept but the message is clear: it is important to stress tissues to give the orientation they need to grow and strengthen. But care is also needed: too much stress would just damage them all over again.

One final topic will round out our investigation into how muscles, fascia, and other connective tissues create stability, strength, and elasticity in our body. This next topic involves the ground substances, the fluids that fill the spaces between the fibers and cells in our tissues.