Concerns with stretching muscles point to one key observation: muscles get tight.
The key question is, "Why?"
Muscles, Stretching, and the Brain
The muscular system is controlled by the nervous system. Muscles have no control of their own. The obvious conclusion to draw is that people get tight muscles because their nervous system is stimulating them to contract.
That being the case, how can someone being stretched by someone else possibly improve their control of their own muscle-tension? To do so requires learning self-control, which is not the point when someone else is stretching you -- or even when you are stretching yourself. The changes that result from stretching are therefore generally unpredictable and unstable -- as evident by the frequency of sports injuries involving hamstsrings.
As a result, people return, by tendency, to the level of tension (and shortening) they experience habitually.
Athletes and dancers attempt to stretch their hamstrings to avoid injury. "Attempt" is the correct word because stretching produces only limited and temporary effects, which is one reason why so many athletes (and dancers) suffer pulled hamstrings and knee problems.
Clearly, whatever benefits stretching confers, it has some significant limitations. More than that, stretching has drawbacks -- and the pun is apt.
As anyone who has had someone stretch their hamstrings for them knows, forcible stretching is usually a painful ordeal. In addition, stretching the hamstrings disrupts their natural coordination with the quadriceps muscles, which is why ones legs feel shaky after stretching the hamstrings. The same is true of stretching any other muscle. More than that, because muscular tension is maintained as a habit (by which we maintain our sense of "normal" tension and posture) that is protected by a postural reflex (the stretch reflex or "myotatic" reflex), forceful stretching provokes that reflex to assert itself even more strongly; the increased muscular tension makes repeated stretching necessary. If one stretches themselves by pitting one muscle group against another (which is what people usually do), the tension of both muscle groups may increase -- a condition referred to as co-contraction.
Fortunately, there is a more effective way to manage muscular tension than by stretching.
No-stretch Stretching
The term is paradoxical, I know, and would seem to imply that nothing gets accomplished toward muscular suppleness. The truth is, you get larger results by this method more easily, than by stretching. You can get instructions to try the technique out, yourself, by following the link at the end of this article.
To understand how it works, one must first start with the recognition that muscles that need stretching are usually holding tension -- that is, they are actively contracting. The person is holding them tense by habit, unconsciously.
Oddly enough, if you try to relax habitually tight muscles by an act of will, you are likely to find that your ability to do so is limited; you cannot relax past a certain point, even with special breathing, visualization, or other non-learning based techniques.
At that point, you may assume that those muscles are completely relaxed and need stretching. You may not realize that you are contracting "on automatic" due to postural habits stored in your central nervous system. Any attempt to stretch them simply re-triggers the impulse to re-contract them to restore the sense of what is "familiar". Hard stretching or "bouncing" stretching is even more counter-productive; it stimulates the stretch reflex to contract the muscles even tighter. That is why hamstrings (and other muscles) tighten up again so soon after stretching or massage. Better results come by changing the person's "set-point" -- their sense of what "relaxed" is.
What Works
... is to shift the resting "tension set point" from continually tense to relaxed-at-rest.
To change the set-point requires more than stretching or massaging; it requires a learning process that affects the brain, which controls the muscular system. Such a learning process is referred to in some circles as "somatic education". Somatic education enhances sensory awareness of muscle tension and the ability to control muscular tension; the brain "wakes up" and muscular (and brain) functioning is enhanced.
How to Get the Effect of a Stretch without Stretching
Instead of stretching, deliberately contract the shortened, tight muscle or muscle group in a coordinated pattern of movement. Put attention on precisely the opposite place to the one you are used to, when you stretch: into the area you are contracting, not the area you feel is being stretched.
Ideally, a coordinated movement pattern involves all the muscles involved in the contraction pattern you seek to free. The action sends a strong sensory signal to your brain, a signal that wakes up (or refreshes) the related nerve pathways in your brain. By releasing the contraction in slow motion, you reawaken or improve your brain's control of the muscles; performance in slow-motion gives the nerve impulses time to travel to-and-from the brain, providing a clearer and more complete body image to oneself. (Nerve impulses travel an average of thirty meters per second. If you are two meters tall, you get between seven and eight "whole-body images" of your own current action per second -- not many, if you are moving quickly.)
Slow motion is the key to somatic exercises and to any other learning process where details make a difference.
Cumulative improvements of flexibility
Significant results come relatively quickly from doing somatic exercises, and when they do, the benefits are second nature and require no special attention in daily life.
At that point, to avoid accumulating tension from stress responses to daily life -- or from conditioning oneself into tension by ones activities -- you might include a few minutes of somatic exercises as part of your daily regimen. Continuing to do them produces cumulative improvements in muscular control and decreases likelihood of injury. With the looseness that develops, you are likely to develop a preference for somatic exercises over stretching.
Some final observations: Muscles are made of fibrous connective tissue made of a substance called "collagen." Collagen behaves something like cloth: it enwraps the contractile cells that give muscle its strength and gives direction to muscles' pull. These collagen fibers have been observed to shorten during sleep (tissue healing/regeneration). Ordinarily, this "microshortening" leads to shrinkage and restriction of muscles and movement, but it gets normalized through somatic exercises or other forms of physical activity. If you don't have some significant movement activity during your days, somatic exercises can help you keep your flexibility. You'll age better.
A similar shortening occurs after significant injury, as collagen fibers invade neighboring tissue to "bandage" the area (scar tissue). This kind of bandaging prevents free movement of just the type attempted in forcible stretching and in stretch-like myofascial release techniques. In that case, precise manual manipulation (myofascial release techniques, e.g., Rolfing, Hellerwork, etc.) to free the adhesions is much more to the point and less likely to induce protective postural reactions than forcible stretching.
SUMMARY
Because conventional stretching techniques produce only temporary benefits and often intensify muscular contractions (as evident in the frequency of injuries among professional athletes), the desired effects of conventional stretching -- suppleness and protection from injury -- can more effectively be obtained via the new "no-stretch stretching" techniques of somatic education. This seemingly counter-intuitive approach produces longer-lasting suppleness than the best of stretching techniques and has the added benefit of improving coordination, which decreases the likelihood of injury.
Here's your chance to test a no-stretch stretching technique for yourself:
Basic Somatic Transformation for Freeing Hamstrings.
Freeing Hamstrings (POINT AND CLICK:) free preview of The Magic of Somatics, a book of somatic exercises
See also: Completing Your Recovery from an Injury
BRIEF:
Lawrence Gold holds certification in Hanna Somatic Education