Good Golgi Miss Molly! What happens when we hold stretches (a brief physiology lesson).

After the past few classes, a number of you have asked about your particular flexibility and/or range of motion when doing asanas. Increasing your flexibility and range of motion requires time, patience, time, acceptance of your body's skeletal limitations, time, respect for past injuries to joints and/or major muscle groups, and yes, more time. I'm not a physical therapist or a physiologist, but I can share with you some knowledge (and a link) to help us understand just what happens when we stretch and elongate our muscles during our practice time together. Once you have a clearer understanding of how stretching actually affects your muscle fibers and how stretching is perceived by your nervous system, it's easier to accept that increasing flexibility and greater range of motion will happen--in time.

In your muscles, just where the muscular fibers meet the tendons, is a Golgi tendon organ. The organ is composed of strands of collagen and contains nerve tissue. The main purpose of the Golgi tendon organ is to sense muscle tension and then send signals to the brain as to where the tension is located and how much force is applied. When you stretch into an asana such as Downward Facing Dog, the Golgi tendons in your body's muscles are sending signals to your brain. The Golgi tendon organs are what actually causes you to realize the "pull" or stretch in your hamstrings, your Achilles tendons, across your shoulders, in your arms, through your quadriceps. When a muscle generates force, the Golgi tendon organ fires and sends an electrical signal through to your central nervous system. If there are any electrical engineers reading this blog, you might enjoy this this superfine graphic animation (physics and physiology, amazing!). In the simplest of terms (speaking as a total moron in the sciences), the Golgi tendon organ enables the location and intensity of muscular activity.

When a muscle is stretched, it automatically responds with a reflexive contraction (this is called, logically enough, the "stretch reflex"). After a certain length of time, the stretch reflex weakens as the muscle gets used to the sensation. One of the reasons for holding a stretch for a prolonged period of time is that as you hold the muscle in a stretched position, the muscle spindle habituates (becomes accustomed to the new length) and the Golgi tendon organ reduces its signaling. Gradually, you can train your stretch receptors to allow greater lengthening of the muscles.

Developing longer muscles doesn't happen overnight. It's downright dangerous to stretch a muscle beyond its limits (some say beyond 7% of its length). How do I know this? My husband completely tore his right rotator cuff when he overloaded his shoulder while moving an overloaded wheelbarrow. Muscles need time to grow and to stretch. It will take him approximately twelve months (and about three hours of physical therapy exercises everyday) to regrow and strengthen the four inches of muscle that he tore in his shoulder. Time, patience, and gentle, regular stretching--all three are important to regaining range of motion and flexibility.

And so, if you feel frustration when you can't touch the mat (yet) when doing a standing forward fold--be patient. Your hamstrings, calves, and back muscles need gentle stretching to lengthen. Don't push your body beyond its limits. Pay attention to the sensations that your Golgi tendon organs send to your brain, stop and spend a few seconds waiting for the stretch reflex to come to habituation (less sensation). Understand that your body is an amazing collection of interdependent systems, with time and patience you will increase your flexibility and range of motion. As my fellow yogini Lois has often said, "Yoga is slow medicine."

Finally, just because you have long muscles in one part of your body, don't assume that all your muscles are equally long. Your particular skeletal structure, primarily determined by genetics, may have given you extra long bones in your arms or legs, thus giving you the gift of being able to wrap your legs and arms with ease in Eagle Pose. You might spend most of your day slouched at a computer terminal and so hunching your shoulders forward in a Cat Stretch feels natural to you. Chances are, for every muscle group that seems to be stubbornly short and inflexible, the opposing group is longer and more supple (biceps/triceps, quads/hamstrings, abs/lower back). That's not a failing on your part--that's just how our bodies are designed.

And there's a negative side to being too flexible as well. Take a look at this illustration of hyperflexibility. Without supervision and guidance, dramatic injuries can occur. Some sources suggest that with extensive training, the stretch reflex of certain muscles can be controlled so that there is little or no reflex contraction in response to a sudden stretch. While this type of control provides the opportunity for the greatest gains in flexibility, it also provides the greatest risk of injury if used improperly. Only consummate professional athletes and dancers at the top of their sport (or art) are believed to actually possess this level of muscular control.

Physiologically, one of the best aspects of hatha yoga is that we spend a lot of time working on all muscle groups in a pose/counterpose system. We work both sides of the body equally. We hold our stretches with patience. We do make progress. It just takes time.

Until next week, namaste!

Nancy