What's in a Stretch?
Stretching. We spend a lot of time doing it in yoga, but do you really understand what's going on in the process? What's the most effective way to go about it? And how can you tell the difference between safe, effective stretching and stretching that causes injury?
There are many different approaches to improving your flexibility, and some are more effective than others. For example, contract-relax techniques, which are part of PNF (Proprioceptive Neuromuscular Facilitation, a system used by physical therapists and others to retrain and facilitate movement patterns) and other systems, can be very helpful but don't fit well into the yoga class format or tradition. Meanwhile, ballistic (bouncing) stretching just isn't a good idea on any level.
Know Your Soft Tissues
Before discussing stretch techniques that are successful and useful in yoga practice, let's take a look at the soft-tissue structures affected by stretching. Looking at the musculoskeletal system, soft tissues of various sizes, shapes and flexibilities—including muscles, tendons, ligaments, and fascia—hold the bones together to form joints. Muscles are formed by contractile cells, which move and position bones by their ability to lengthen and shorten. Connective tissue (CT) is noncontractile, tough, fibrous tissue, and it may or may not be flexible, depending on its function and its ratio of elastic to nonelastic fibers. Ligaments, which join bone to bone, and tendons, which join muscle to bone, are comprised primarily of nonelastic fibers.
On the other hand, fascia (another type of CT) can be quite flexible, as it contains more elastic fibers. It's found throughout the body and can vary in size from microscopic, as in the tiny fibers that help hold the skin onto underlying bones and muscles, to large sheets, such as the iliotibial band that runs from the side pelvis to the outer lower leg and helps stabilize the torso over the leg while standing. Basically, fascia holds all of the layers of the body together, including binding the muscle cells into bundles and bundles into distinct muscles that we know by name. It's been said that if all other types of cells were somehow dissolved, leaving only fascia, a clearly recognizable body would remain.
Consider the Need
When your students are stretching, you'll need to consider all of the different types of soft tissues and how (or whether) to increase their flexibility, as each has different needs and requirements. Help your students to train the muscle fibers themselves to relax into the stretch, so they're not contracting and trying to shorten instead of lengthening. If your student pushes a stretch into pain, the muscle will contract to guard itself against tearing. If your student suddenly puts a muscle into an intense stretch, she will likely elicit the stretch reflex, which also causes the muscle to contract. Instead, instruct students to ease gradually into the stretch sensation and find their "edge," where they start to feel some resistance, maybe even a little discomfort—but not pain. Request that they breathe and relax into the stretch, visualizing the muscle lengthening and letting go of its contraction: The body takes literally what the mind is picturing. Over time—not instantly—their bodies will build more length into the muscle structure.
Because ligaments and most tendons attach to bones very near to the joint itself and are relatively inflexible, they help to hold the bones in place and thereby stabilize the joint. Most physical therapists discourage the stretching of tendons and ligaments, due to the risk of hypermobility (too much movement, or movement beyond the normal range) at the joint. Hypermobility can cause or contribute to a number of joint problems, including arthritis, dislocations, and torn tendons and ligaments. Therefore, students should avoid feeling stretch or pain in or directly around a joint, unless they are working with a healthcare provider or very experienced teacher who has determined that a specific tendon or ligament is lacking its normal flexibility (often as a result of injury or scar tissue) and is supervising careful work with the problem structure.
You'll certainly need to consider the fascia, too, as it is so deeply entwined in the muscle structure at every level. Physical therapy research has shown that in order to change the structure of fascia, you would need to hold a pull on it for 90-120 seconds. This information also supports the idea of holding a longer, gentler stretch, since who wants to sit through two minutes of pain? I've noticed that if a stretch is intensely painful, most of us want to get it over with quickly and will avoid practicing it regularly. Our minds want to "escape" and go elsewhere, which is opposite of the yogic goal of being present and conscious in our actions. Not only that, but the pain probably indicates that some tearing of tissue is taking place. Microscopic tearing is probably acceptable, even necessary, to prompt the body to rebuild and remodel the tissue according to the new, more flexible blueprint. However, bigger tears, which can leave the muscle sore for several days or more, are repaired with scar tissue, which is never as flexible as normal tissue and is therefore to be avoided.
The bottom line? Instead of quick, intense, painful stretching, set your students up in a relatively comfortable position to stretch the desired muscle(s). They should be able to linger for about two minutes while breathing and relaxing into the stretch with a soft, meditative focus. Ideally, lead them in practice warming poses before they stretch deeply, as warm muscles relax and stretch much more readily than cold muscles. Because this approach feels good, they will be more likely to practice the stretching more often. If your students can practice long, gentle stretches of their chosen area four to six times each week, they'll be pleased with their progress in flexibility, as they become a more conscious, compassionate practitioner.