Bones, ligaments, muscles, and tendons all weave together into a dynamic whole. The skeletal portion of the musculoskeletal system is made up of the bones, ligaments, and other tissues that make up the joints. The muscular portion is made up of the muscles and tendons that cross the joint space and attach to the bones, as well as the nerve endings that organize the exquisite sequencing and timing of our muscle actions. All of these tissues are either composed of or wrapped in layers of connective tissue.
The skeletal system and the muscular system are often treated as separate systems. When we consider how movement is generated, it makes more sense to think of them as one skeletomuscular system. The muscles and bones work intimately together to negotiate our relationships to gravity and space, to provide movements.
Without the structure and support of the skeletal system, the muscles would be a puddle of contractile tissue with nothing to move. On the other hand, without the movement created by muscles, the bones would be unable to move through space and could only respond to forces outside the body travelling through them. Without connective tissue such as ligaments and tendons, bones and muscles would have no way to relate to each other.
One job of the bones is to receive weight and transmit force, while the ligaments direct that force along specific pathways. The job of the muscular system is to move the bones into positions where they can do their job as effectively as possible.
When we assume that we can generate a final and complete analysis of the unique and complex sequences of muscular action that are expressed in each person’s movement choices, we create obstacles and limit the ways that new choices can arise. If we instead observe with a mind open to possibilities, examining each person’s pattern becomes an opportunity to witness the incredible variety of ways that we can successfully execute the simplest actions.
An asana, or yoga pose, is a container for an experience. An asana is not an exercise for strengthening or stretching a particular muscle or muscle group, although it might have that effect.
It is a form that we inhabit for a moment, a shape that we move into and out of, a place where we might choose to pause in the continuously flowing movement of life. In yoga poses, we experience a cross-section of a never-ending progression of movement and breath, extending infinitely forward and backward in time.
Each asana is a whole-body practice where we can witness how things arise, how they are sustained, and how they dissolve or are transformed. We can see how we are affected by the experience of moving into the pose, being in the pose, and moving out of the pose, and how that might affect other places in our lives where we meet change. As long as we are in the matrix of space and time, we are never actually still.1
Our choices about how to move through an asana will depend on our starting condition. For example, if I have very open shoulders, then I might think about internally rotating the humerus relative to the scapula, while my neighbor with less mobility in the glenohumeral joint is rolling the arms open as much as she can. Both actions could be functional in adho mukha svanasana (downward-facing dog pose) because the point of the asana (on a body level) is not to do it right, but to find the relationship between all the parts of the body that will let the experience of the asana resonate throughout the whole body—cells, tissues, fluids, and systems.
The ways we initiate a movement, whether from the bones and muscles or from the endocrine system or the blood, have a tremendous impact on the quality of the movement. With practice and skillful observation, we can see from the initiation how the movement will travel through the body and the effect it will have on the body systems. An understanding of what we are activating to move into an asana will help us understand the nature of the asana and the effect it has on the skeletal, muscular, nervous, and endocrine systems; the mind; and the spirit.
The asana is not just the final arrangement of the limbs and spine but is the full process of coming into that arrangement. If we look at the process rather than the final product, we are able to develop variations that increase or decrease the challenge of the asana without feeling that we aren’t actually doing the asana until we get our head to our knee, our hands to the floor, or some other concrete goal. We are able to adapt the asana to the individual so that each person can find a unique embodiment of the asana.
Because yoga practice is fundamentally experiential, the knowledge and understanding of your musculoskeletal system is intended to be an inspiration to explore your own body.