What Happens When We Stretch?

What exactly happens when we stretch? We all know something gives. The longer we reach for our toes, the easier it is to grasp them.

What we’ve learned through science is that it isn’t just one thing. Stretching is actually pretty dang complicated.
First the Anatomy[/B][/B]

Each muscle fiber is wrapped up in fascia, a material a little like the plastic wrap you could see surrounding a leftover chicken leg in the fridge. Each individual muscle fiber wrapped up in its fascia is then collected into a group with another coating of fascia holding the group together. Then several of those groups of muscle fibers are bundled together in one big group of muscle surrounded by a bigger, thicker layer of fascia.

As the muscle nears a bone, it thins and becomes tapered. The fascia covering each fiber as well as that surrounding the groups of fibers continues and becomes a tendon that forms the connection of muscle to bone. Scientists call this entire structure the muscle-tendon complex. It’s considered one unit because muscle and connective tissue (fascia and tendons) are so intimately connected and intertwined that studying only one or the other is difficult. Having said that, they’ve been able to tease out what is happening to each of them when we stretch.

[B]The Muscle Component[/B]

Stretching muscle causes a reflex mechanism in the spinal cord– sort of like the reflex a doctor elicits when she taps your knee and your leg jerks. Sensitive receptors known as [B]muscle spindles[/B] are located throughout the length of the muscle. Muscle spindles note a change in muscle length during a stretch as well as how fast the stretch has occurred. They send this information to the spine. That triggers the stretch reflex which attempts to resist the change in muscle length by causing the stretched muscle to contract. The more sudden the change in muscle length, the stronger the muscle contractions will be. (And that is one reason you want to go slowly into a stretch without any rapid sudden movement.) This reflex helps to maintain muscle tone and upright posture and to protect the body from injury. The longer you hold an asana and stretch the muscle, the less the muscle spindles can do their job. They only work for a short while. After time, their effect goes away. When that happens, you get a little more length during the stretch because the muscle stops contracting.

There’s another reflex mechanism involving sensory receptors called [B]golgi tendons[/B] which lie at the tapered ends of muscles where the tendon is forming from the fascia. These sensors are activated when a muscle is stretched a little farther. Their job is to send information to the spinal cord to elicit muscle relaxation to prevent excessive strain and subsequent injury.

Hundreds of sarcomeres make up each individual muscle fiber. They are divided into bands composed of either actin or myosin. During contraction of a muscle, those bands slide over one another causing the muscle to shorten. The actin and myosin bands are connected to each other by [B]chemical bonds[/B]. Stretching causing some of those bonds to break allowing the muscle to lengthen.

Sarcomeres are also elastic. Over half of each sarcomere is composed of a protein called titin that gives it elasticity. [B]Titin[/B] acts like a rubber band. It has the ability to increase the length of a muscle when stretched and then to shorten to the original length when the stretch is released. First its overall shape changes to become elongated and then with increasing force of a stretch, the protein unfolds from its three dimensional structure. The result is a lengthened sarcomere and therefore a longer muscle.

[B]Connective Tissue Component: Fascia and Tendons[/B]

[I]More than half[/I] of an initial change in length, the give of releasing into a stretch, is due to elasticity of the connective tissue. It’s like a rubber band.

In addition to its elastic component, connective tissue creeps with longer duration stretches. That is, stretching for a few minutes causes a [B]reorientation of the collagen fibers[/B] within it to a more ordered array. They line themselves up in parallel to provide more lengthening.

Tendon fibers are pretty much already in parallel to one another, but fascia fibers are more willy-nilly. Most of the [B]creep[/B] is due to reorientation of the collagen fibers in fascia to an ordered parallel arrangement. The fibers begin to line up like rows of soldiers coming to attention, providing additional lengthening and stretching.

Creep is what gives connective tissue its ability to maintain length, and therefore flexibility, over the long term. The effect doesn’t go away a few minutes after you release the stretch. It’s the more permanent aspect of increased flexibility.

All those other stretch mechanisms occur first. Then, with time, the creep of connective tissue begins. Exactly how long one needs to maintain a stretch to produce creep isn’t clear. It may occur in four or five minutes. By ten minutes it is more likely to be happening.

Fascia creep can progressively increase length at time frames of at least up to one hour. In fact, in one experiment, an entire third of the total lengthening from a stretch took place during the latter part of the hour.

[B]Mind Component[/B]

The mind plays a role here. Some researches believe that much of our ability to lengthen muscle-tendon complexes and to increase flexibility comes from our brains’ ability to alter how we feel in response to a stretch. Usually our stretches are stopped by a sensation of discomfort or even, when the stretch is forced beyond that point, outright pain.

Over time the exact point at which a stretch makes us feel uncomfortable may tend to increase with a period of repeated stretching exercises. In other words, the maximum amount of stretch we could tolerate last week might be much less that we can tolerate today because our mind simply doesn’t act to stop the stretch because of a perception of pain.

Pain is a protective response. We quickly pull our hand away from a burner because the brain knows that a burn that will destroy our tissue. Maybe the brain actually “learns” that a stretch to a certain point is ultimately not harmful and so it has figured out that stretching to that point is okay and it no longer elicits a sensation of “ouch.”

[B]Are longer duration stretches beneficial?[/B]

Stretching fascia is the primary way to increase the range of motion of joints in a lasting way. While the other stretch mechanisms provide temporary lengthening, it is the creep effect of fascia which contributes the most to long-term flexibility.

Especially for those with a reduced range of motion from disease or an extended period of inactivity, prolonged stretches can greatly improve function. This has been seen clinically with stretches of the rotator cuff and with a tendon on the bottom of the foot that often shortens and tightens causing pain and disability. Longer stretches incorporating the creep effect can be very healing.

There’s also some evidence that gentle stretching elicits an anti-inflammatory response within the muscle and connective tissue. With more forceful stretches, there’s a counterproductive pro-inflammatory effect. Long gentle stretches may help to reduce inflammation leading to tendonitis.

[B]Bit of Caution[/B]

Bobbing stretches that are rapid and short can strain the muscles and connective tissue resulting in tears. [I]Don’t bounce.[/I]

Warm muscles stretch better than cold ones. Temperature can significantly influence flexibility. A five minute [I]warm-up[/I] period of general increased activity is wise for best effects and less injury.

There may be a relationship between long duration stretches and the maximal amount of force a muscle can provide. If you really need absolute maximum power, longer duration stretches may not be for you. One group of researches found that a small surgical release of fascia resulted in a 15% reduction in force production due to a lowered compartment pressure. That [I]may[/I] translate to a [I]reduction of maximum strength[/I] after prolonged stretching. Some body builders, though, like to stretch their fascia to make room for greater muscle growth since their concern is bulk and not power.


Traditional Yoga texts suggest that asanas were initially intended as postures for meditation. The greatest yogis spent prolonged periods of time in classic postures like pascimottanasana, padmasana, and bhadrasana.

Holding a stretch for an extended period in a relaxed manner provides an opportunity for meditation and allows for a deeper level of awareness of the energy body. On a musculoskeletal level, these longer duration stretches primarily release fascia, and they can significantly improve long-term flexibility and function.

A list of scientific references can be found on theYogadr.com.

nice. thanks for sharing.

Love coming across well research information. It gives me the ability to touch up on my exercise physiology. The article is well written and cant wait to read some more posts. In my profession, I utilize knowledge as a main part of my practice. This allows me to inform the individuals about the specifics, just like you guys are doing here. I’m very impressed with this forum.

great article! thanks

“The longer you hold an asana and stretch the muscle, the less the muscle spindles can do their job. They only work for a short while. After time, their effect goes away.”

thank you for sharing this! we were just talking about this is our class at surf berbere yoga in morocco

If I’d like to share some of this and quote you, what would you like the attribution to be? Do you have a website for me to link to?

Nevermind, found your real name and website at the bottom of your post.

Proper attribution would be to yogaforums.com

Thank you :slight_smile:

Good article, look up a book such as Pavel Tsatsouline’s ‘Relax Into Stretch’ which really explains stretching theory well, and in a manner different to general yoga theory.

There is no breath count option in the poll. I usually do 12 breaths when I do a posture combined into a set of postures. That would be around a minute if I am not mistaken. I defeinitley do not hold any of them for 5 minutes or longer, except sitting in meditation, but I doubt sitting on a chair counts as an asana.

Is sex similar to yoga stretching?

Because I’ve read an article about this one and it really catches my attention…
That holding your breath in such period could enhance your sexual libido. Base on research it allows muscle manipulation and control.

What do you think?

[B]Is yoga actually bad for you?[/B]

Yoga has been practiced for more than 5,000 years, and currently, close to 11 million Americans are enjoying its health benefits. Yoga can hardly be called a trend.

Madonna and Sting are fans, Roy Keane’s done it and even the Leinster rugby team have given it a go. Once seen as the domain of cheesecloth-wearing hippies, yoga is now the discipline of choice for anyone who wants to improve strength, balance and mental well-being.

With the wealth of studios, gym-based classes as well as lessons in schools and church halls, it’s impossible to judge just how many people in Ireland practise yoga, but a conservative estimate puts Irish yogis in the tens of thousands.

Put it this way: less than 10 years ago there were just three or four yoga studios in the greater Dublin area – now there are 50.

Aficionados are quick to praise it for curing bad backs, improving posture or helping them unwind after a stressful day’s work.

Celebrities love it. Gwyneth Paltrow, who practises six days a week, says: “Yoga has completely changed me. . . the effect is amazing,” while Jennifer Aniston, who does it an hour a day, gushes: “It’s a therapy session, a workout and a meditation all at the same time.”

I always hate to be at all contradictory, but there are a few problems with this explanation about stretching.

1.) The idea that the Golgi Tendon Organs (GTOs) “prevent excessive strain” is from the old understandings of GTOs. They are not just protective from excessive stretch, but are directly involved with the stretch/contraction mechanisms in their entire spectrum of motion. It was discovered in the 1970s that the GTOs are far more sensitive than was originally thought, and actually measure the degree of contraction or stretch to a muscle from their zero point, and are directly involved in the entire range of their action/ relaxation. But medical research being what it is, it has taken a couple of decades for this fact to enter the educational track.

The implication for yogis here is that IF you maintain a VERY mild and low-intensity stretching action from the very beginning of your asana action, and let the GTOs do their thing before the muscle spindles (stretch reflexes) have time to activate, than you’ll be using the natural, built-in-by-nature forces within your bodymind to begin the relaxation processes.

The yogic, meditative component here is to allow the self-sensitive mind to consciously restrain your initial, excessive ambition to get into the posture or asana too deeply, too quickly.

2.) The idea of actin-myosin bonds “breaking” gives, I believe, the wrong impression here. This is a subtle distinction, but that sounds too much like tearing or spraining or whatever. From a yogic point of view, the state of “being relaxed” is when the actin-myosin bonds are “non-activated,” or in a Buddhist sense, “non-doing by non-activation.” So, the ACT of relaxation is about “DE-activating” the bonding action of the actin-myosin fibers within the muscle cells.

So, the bonds don’t “break” in the ordinary sense of the word, but the chemical bonds “de-activate” which is what allows the actin-myosin fibers to UN-overlap, sliding out from each other, which is THE essence of neuromuscular-fascial relaxation.

Yes, this distinction is subtle but, in my opinion, from a physiological point-of-view, this is THE most important understanding necessary to grasp what musculo-fascial relaxation is really all about.

3.) “Sarcomeres are also elastic.” “… titin that gives it elasticity.” I’ll keep this short by saying that titin cannot express it’s “elasticity” or “rubber band nature” unless the nerve charge to the actin-myosin fibers is turned off. The actin-myosin fibers themselves have the tensile strength of about half that of steel wire. They are, independently, almost totally resistant to “stretching” like rubber bands. It is only when you have learned, through yogic, meditative processes, to totally turn off the neuromuscular nerve charge (tonus) to the actin-myosin fibers that the titin elements of elasticity make any difference at all.

So, regardless of the “elasticity” of the titin fibers, sarcomeres cannot lengthen until you’ve learned to turn off the nerve charge (tonus) to your actin-myosin fibers. And muscle fibers will not lengthen without tearing until you’ve turned off the nerve charge to the actin-myosin fibers.

This means, bottom line, that so-called “elasticity” in the muscles (and fascia too) is almost, if not completely, irrelevant to being able to bend deeper into an asana.

4.) " … elasticity of the connective tissue. It?s like a rubber band." No, it’s not. This is an illusion. Every single research paper or anatomy/physiology book I’ve seen says that fascia – especially the deep fascia of the muscle fibers – has from 4 to 7 percent extensibility, MAXIMUM. In fact, it is this reality that gives the fascia/tendon unit one of its primary values. Ideally, the fascial/tendon unit efficiently transmits the force generated by the actin-myosin units to the bones. IF the fascia/tendon units were truly as extensible as a rubber band, we would lose massive amounts of muscular force as the fascial/tendon units stretched out. We’d move around like rag dolls instead.

Muscle and fascia being like rubber bands is one of the Great & Dangerous Myths of yoga and bodywork. It leads people to produce diagnoses and treatments that are NOT in accord with reality.

5.) The facial creep idea is probably more related to human being UN-learning their old muscular tension patterns. It might also be the fact that the human body will reduce the number of sarcomeres in a muscle if it falls into disuse. But the body will replace sarcomeres when the muscles comes back into more use. This is probably the single most un-researched or explored element of restoring flexibility I’ve run into. How long, and to what degree, does one need to be, in a “stretch” before the body starts replacing lost sarcomeres. I’ve seen next to nothing on this topic, unfortunately.

6.) The “Mind Component” is, as I said above, primarily about the mind learning to turn off the excess charge of tonus to the actin-myosin cells. That is the psycho-neuro-musculo-fascial NEXUS between mind and body. If we are working within what I call our minimum to moderate edges, rather than our maximum edges (where, unfortunately, most people tend to hang out) we’ll get far better results because we are not pushing our tissues and nervous system too far, too deep, too fast.

7.) “Stretching fascia is the primary way to increase the range of motion of joints.” I believe that, once people get over their excessive fascination for fascia (see comment below on Ida Rolf and Alfred Korzybski), and realize that facia and muscle fiber are totally and intimately related tissues with a very high division of labor (that being one of the most prevalent and important characteristics of being human), they will stop ignoring the facts about fascia, and realize that it is the NON-elasticity yet very high degree of flexibility (bend-ability, which does NOT mean they can lengthen much at all) of fascia that makes them so useful.

8.) Bouncing and Warming Up … In my view, after 40 plus years of direct experience and extensive theoretical research, when it comes to “Yogic Warming Up,” muscle temperature is nearly irrelevant. Properly Preparing the muscle is about reducing the initial psycho-neuro-muscular charge that is the first gate toward flexibility and fluid motion. So what’s relevant is reducing the habitual nerve charge to the muscles is what is more important to everything else.

9.) As far as traditional texts and yoga postures go, I refer to you to Mark Singleton’s book, Yoga Body, where he conclusively demonstrates that all but maybe 8 or so so-called yoga postures were actually from fitness and gymnastics in Europe in the late 1800s. The vast majority of yoga asana were not practiced AT ALL by any of the ancient yogis. Modern yoga asana practice is of very recent origin, and has no ancient lineage.

BottomLine: It is amazing to observe the so-called experts talk about how fascia is so resistant to stretching and lengthening on one hand, then, with no apparent awareness of their contradiction, talk about restoring its alleged “elasticity.” Fascia is NOT elastic, beyond 4 to 7 percent.

It is the learned capacity of the thinking/feeling/meditative mind to sink its way down through the nerves to the actin-myosin cells that produces the relaxation of those actin-mysoin units, allowing them to relax and lengthen, that produce true, learned flexibility, rather than the far more common “forced flexibility” which is achieved, if at all, by willpower and NON-meditative, NON-yogic processes.

Elasticity can mean “bend-ability” or “length-ability.” Fascia is highly bendable with high degree of strength, and very little length-ability. Muscle has a high degree of length-ability, but while it IS very bendable, it is VERY fragile in its bendable state. This is the beauty of the musculo-fascial unity. They have an exquisite and highly useful combination of both.

Ida Rolf was a student of Alfred Korzybski who had a lot to say about the fascial tissues and the part they played in many aspects of human life and health. Ida began saying everyone was talking about muscle, and not about fascia. That was probably true at the time. But now, everyone is talking about fascia, and not much about muscle. I hope to bring more people back to a balanced view of both tissues in harmonious relation to each other.

GTO’s wow! that’s explains a lot… Hoping to see more discussion.

I’ve read an article about pain, that the more depression being experience the more our mind get stress and might lead to different illnesses. Meditation techniques really helps me a lot as you could see I’m very interested about meditation and yoga .This site really add a good insight about meditation and the benefits to our mind, body, social attitude and the greatness of being relieve from pain through meditation.

Please tell me more about meditation techniques.

Stretching distributed prana through body.

Very interesting. Definitely knew it wasn’t good to bounce in stretches but didn’t know it was possible to tear muscles.