Some Truths About Stretching and Flexibility in Yoga

One of the key benefits and primary interests for people doing yoga is to increase flexibility and joint range of motion. I have compiled expert opinions on the physiology of stretching.

Elastic Edge:

Muscles, tendons, and ligaments have an ‘elastic edge’ where by they can stretch to a certain length under force and then return to resting length. Overall, there is a set ‘length’ for the elastic edge of all these tissues.  Muscles have a much longer edge than tendons and ligaments.  Once this edge has been passed, tearing and damage readily occurs.  As we develop our flexibility over time, we can readily adapt into the muscular edge and pass too much force into the shorter ‘edges’ of other connective tissue – this is where we see the onset of impingement, tendonitis, bursitis, and connective tissue tears occurring.  It is common for those beginning a yoga practice to see significant flexibility gains in muscle tissue – just remain mindful that tendons and ligaments required greater adaptation time.

Sensitivity to Elastic Edge:

As we progress with consistent flexibility training, it is common with increased range of motion that we have decreased sensitivity to our true elastic edge by altering our reflex sensitivity in muscle stretch receptors.  For those starting in flexibility training and yoga, they will feel a sense of stiffness and ‘resistance’ sooner than those who have been practicing for extended periods.  This is part of protection mechanisms in muscle and connective tissue.  With practice, we can override these mechanisms to allow us to ease into these edges with less sensitivity.  The downside is, if we are practicing with ego, we do not have these mechanisms effectively telling us when to stop and become more susceptible to passing elastic edges and causing injury.

muscle anatomy and sacromeresFlexibility Comes With Consistency:

Doing a single yoga practice can create the sensation of tension release, but due to elastic qualities, tissues within minutes return to their original resting length. A single practice here and there will not increase overall flexibility and muscle length.  Muscles lengthen by increasing the microscopic subunits called sarcomeres at the muscle-tendon junction.  We can also manipulate the orientation of collagen in connective tissue to allow for SOME (note SOME in the limited sense) greater elastic length potential. The addition of sarcomeres and enhanced collagen orientation only occurs with regular, consistent, progress practices.

What Makes Me Feel Stiff:

Stiffness is partially related to overall muscle and connective tissue length. We can not change what is called technical “stiffness” without without adding on more sarcomeres or manipulating collagen orientation. We may experience extra stiffness due to muscle conditioning (force loads or stretching that cause micro-fiber tears … common in weight training programs).  We may develop adhesions in fascia (connective tissue surrounding and supporting muscles).  We may also have adhesions at the sarcomere-level in components called titin which are responsible for passive tension and for returning muscle filaments back to resting length after  being stretched.  In the case of fascial adhesions (often caused by dominance of poor posture or activities OR from injury), you may need to receive specialized treatments to break down the adhesions and prevent scar formation. Flexibility programs like yoga work directly on fascia to prevent adhesion formation and maintain fluid motion among the fascia and muscle.  Stretching programs are showing to have some influence on titin – for example: longer titin units results in tension at longer sarcomere length, therefore being able to reach elastic limit at higher sarcomere lengths.  Stretching may increase titin unit length especially in stretching programs with youth.  Much more research is underway addressing the effects of flexibility practices at the sarcomere level.

Flexibility and Age:

As we age, we lose sarcomere units meaning reduced overall muscle length and increased stiffness.  With age, we experience changes in collagen structure in connective tissue leading to decreased compliance in tendons and ligaments.  Stretching programs can reduce the onset of these age-related tissue changes.

Stretching and Other Activities:

Progressive stretching has shown to reduce maximal force output of muscle tissue.  Therefore, it is not advised to do deep stretching prior to activities requiring vigorous force generation.  Instead, slow and gradual warming of tissues mimicking movements to be performed (easing through joint range of motion) in those activities is preferred.  So, if you plan to do yoga and weights in the same day, best to do the yoga after your training.

Ideal Way to Stretch to Develop Flexibility:

Researchers have fully concluded that there is not enough research to adequately conclude what is the best way to stretch in order to develop flexibility.  Given the vast number of variables: age, gender, predisposition to muscle fiber types, types of stretching, length of time, muscle isolation versus multi-muscle integration, goal specific training, etc, researchers are far from offering any concrete prescriptions.  They clearly do recognize the benefits of stretching and most advocate exploring methods that your body readily responds to and suits your specific needs.  This pretty much resonates the overall intention we should have within our practice: discover your uniqueness.

13 Replies to “Some Truths About Stretching and Flexibility in Yoga”

  1. Thanks Kreg. What an excellent and clear article. I am curious to know your perspective on how Yin yoga can be wisely practiced given all these variables.

    1. Hi Irene,
      Yin Yoga does have its’ benefits, no doubt. I have hesitations when hearing from some Yin teachers that Yin is designed to move into connective tissue. Yes, stretching does benefit tendons in helping orientating the collagen to combat blockages of compliance. However, to practice with the intent to ‘increase’ flexibility via connective tissue doesn’t make a whole lot of sense to me especially coming from a fitness and sport background. Connective tissue is meant to do exactly that CONNECT. For those practicing Yin, consider what other activities are also being done. Laxity of connective tissue (tendons and ligaments) makes joint more prone to injury. Given that Yin Yoga does not engage muscles, the muscles are not conditioned to take on the extra role of joint support needed.

      So, my answer would be more of a question:
      *what are the intentions when someone is doing Yin Yoga? and do those intentions mesh with the rest of the person’s lifestyle?
      *does the person have a predisposition to already being flexible? if so, maybe they should be doing another form of yoga or fitness modality that actually strengthens versus increasing laxity in the joints
      *does the teacher applying Yin principles FULLY understand the biomechanics and force loads (gravity) being applied to joints? especially in regards to poses that place loads on the knees (ie pigeon, hero, cow face)

      I am one for balance – I find that one can easily settle to extremes in yoga (hot yoga, ashtanga, endless props, overuse of bandhas). I think Yin can have a valuable place in practice as long as there is balance and understanding – and more so, with an appreciation that we are individual and not all poses in all variations and approaches are appropriate.

  2. Aging process is result of lack of circulation and pore digestion.opposing practices must be done not same thing every day.dehydration comes from poor circulation and a daily over aggressive practice need to change it up to keep body fluid and hydrated.

    1. At the connective tissue level, there is more to it than just movement and dehydration. Though these are very important components, the actual collagen fibers build up greater and greater hydrogen bonds over time…bonds that cannot be broken by just movement and hydration. Physical manipulation is necessary to pull these fibers about and reorganize their hydrogen.

      Staying mobile and hydrated can help mitigate, but not eliminate this occurrence.

  3. This is very apt as I have been trying to find more information on this. I’m a yoga teacher and perhaps less conventional in thinking that flexibility is partly to do with genetics. I believe that some people are just less flexible and some more flexible and to an extent it’s in our genes. So for some even a regular yoga practice won’t mean they become that much more flexible, do you agree?

  4. Good article, I’m interested in this topic, as a Yoga teacher myself. It seems to be that too much emphasis is on being extremely flexible. Yoga is certainly beneficial and helps with maintaining and possibly slightly increasing flexibility in some and a lot in others. As you imply it’s not black and white, there are a lot of factors. So do you think that some people however much they practice yoga will not gain much of an improvement in flexibility?

    1. Hi Sophie, Yes there are so many variables (genetics, lifestyle, gender, age, conditioning) that can determine one’s ability to gain flexibility. I think there are many situations where a person may not be able to acquire substantial gain in muscle length, but the benefits of stretching / yoga would still be hugely important. Even for those unable to develop extra flexibility, stretching programs will likely maintain current range of motion especially as they age, reduce the chances of chronic or acute injury, offer re-balancing of the musculoskeletal system, and promote circulation and tissue recovery.

  5. What would you suggest as an ideal room temperature for a Yin Yoga class?
    Kimberly Bayer aka “Yogi Bayer”
    College Health Education/P.E. Professor
    RYT 200+ Yoga teacher

    1. Hi Kimberly, There are different attitudes towards room temperature in. I have heard everything from cool (to target connective tissue) to hot yin. I personally would have comfortable room temperature where a person doesn’t feel cold lying down and will generate internal warmth simply with yogic breathing.

  6. Hi Kreg
    Another question- approx how many postures in an Yin sequence in an hour format?
    5 min silence seated in mindful meditation, followed by each pose held for 5-10 minutes? Should we limit the number to somewhere between 5-8?
    Is less more?
    Thank you

    1. Hi Kimberly, Yes, yin yoga has a much smaller number of poses compared to hatha yoga. So, depending on the class length, you would be guiding the class through 5 to 8 poses.

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