EXPERT Q&A ON YOGA, STRETCHING & INJURIES W/GREG LEHMAN

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As a member of the yoga community for many years, I regularly hear claims made about how stretching affects the body. These claims vary widely, and I’ve heard everything from “stretching is a magical cure that will heal all of your ailments” to “stretching is damaging for the body, and therefore yoga is bad for us.”

I try to be as evidence-based as possible in my approach to yoga, so I’m naturally skeptical of claims that appear to lack scientific support. In order to clarify some of the truth versus fiction regarding stretching for both myself and the greater yoga community, I decided to consult with an expert who is extremely up-to-date on the most current scientific research on stretching.

Dr. Greg Lehman, BKin, MSc, DC, MScPT, is a Clinical Educator, Physiotherapist, Chiropractor, and Strength and Conditioning Specialist. He travels the world teaching his Reconciling Biomechanics with Pain Science course to health & fitness professionals. He is also the creator of the “Recovery Strategies” pain workbook, which is an amazing, informative, and free resource for anyone in pain. Greg’s work has had a profound impact on the therapeutic, fitness, and yoga/movement worlds, and I am incredibly honored to feature his insight on my blog!

YOGA & STRETCHING Q&A W/GREG LEHMAN

QUESTION 1: In the yoga world, there is a widespread claim that stretching can lengthen connective tissues like ligaments & tendons, causing them to become lax and leading to "joint instability". Is this a biologically plausible assertion?

ANSWER: There is no evidence that this actually happens.  Pretty unbelievable, eh? There is certainly more evidence that suggests when you pull (apply tension) to connective tissue it responds by getting stiffer, stronger and sometimes thicker.  Old research by Dr. Woo has shown this consistently.  The only consistent thing that can make connective tissue less stiff is immobilization and injury.  So, it is possible that people who gain massive amounts of flexibility may have at some point damaged their tissue. 

If people feel “lax” because they stretch I would guess that it would be more of muscle or nervous system change.  People may not have the strength in those ranges to control the motion rather than the idea that they lengthened connective tissue constraints.

 

QUESTION 2: What exactly does "stability" mean when it comes to our joints, and is there evidence to support that a lack of joint stability causes pain and/or dysfunction?

ANSWER: A stable joint system just means when it gets perturbed or jostled it comes back to its resting place.  But, people have expanded the definition to mean that a joint just moves a lot when you don’t want it to move.  Joint instability is a problem when a joint pops out of place and does not readily go back into place.  It certainly does happen but I doubt it’s that common.

 

QUESTION 3: Can passively stretching a muscle compromise its strength (i.e. decrease its ability to produce force)?

ANSWER: Not significantly, meaning 1-5% of max force production [if stretching immediately prior to a strength activity].  And since we regularly don’t need to produce max force it’s not really an issue.  And you only get this transient force reduction when you hold a static stretch for 45 or more seconds.  Some research (Blazevich) even suggests that these max force/power losses are mitigated or completely ameliorated provided you do a warm up.

There is no reason to think that long-term stretching will make you weak.

 

QUESTION 4: Aside from concerns about lengthening ligaments & tendons that we've already covered here, is it inherently injurious or damaging for the body to spend time in passive end range stretches? What about for someone with a connective tissue disorder such as generalized joint hypermobility (GJH) or Ehlers-Danlos Syndrome (EDS)?

ANSWER: I think with EDS it makes sense to limit those movements and get strong instead.  That’s one of those conditions where shit really does pop out of place.  But for other people, who cares if you hang out at end range. You are just applying tensile load to tissue (pretty much what strength training does but at other ROMs) and the tissue will adapt by getting stronger. 

We aren’t made of taffy.  We don’t really “stretch” that way with applied loading like end ROM stretching.  I don’t think it’s injurious but you could certainly argue that there are better options to achieve health and mobility – like adding strength training or even resistance throughout the range of motion.

 

QUESTION 5: There is a growing dialog in the yoga world about the distinction between active & passive stretching, with a new emphasis being placed on the benefits of training active strength & control through our ranges of motion ("active stretching") and a de-emphasis being placed on passive stretching. The reasoning goes that if we have more passive ROM available at a joint than active ROM, we are more susceptible to injury because we lack "control" in those end ranges. Would you agree with this line of thought?

ANSWER: I think you should do both.  I wouldn’t be worried about injury though.  I don’t think most people are getting injured because they have lost “control” of the joint.  Further, if you get injured because the joint suddenly goes to end ROM, it’s not strength at end ROM that would have helped you - it’s the strength and control that you needed before you went to end ROM. 

 

QUESTION 6: Many long-term yoga practitioners have discovered through imaging that they have a hip labral tear, and yoga is often blamed as the cause of this tear. Given that yoga is a low-load activity and that a majority of people in general will develop an asymptomatic labral tear as they age [Ref, Ref, Ref, Ref], is a long-term yoga practice a likely cause of a hip labral tear?

ANSWER: Labral tears are common. Heck, they might even be beneficial for performance.  It’s not unreasonable to think that ANY activity can predispose you to joint changes.  They happen and I doubt there is much we can do about it.  You will see labral tears and bony changes in most sports. 

So should we stop physical activity because of the chance of a labral tear? No. There are way too many benefits from a movement practice that far outweigh the negatives of a potential increase in the chance of having a labral tear.

 

QUESTION 7: In terms of stretching physiology, I believe that many people conflate the "muscle spindle stretch reflex" (reflexive muscular contraction during a stretch) with "stretch tolerance" (tolerating the discomfort of stretching) in their minds. Could you describe the difference between these two phenomena? Do they both play a role in stopping us at the end range of a stretch?

ANSWER: I’m not sure to be honest.  Stretch tolerance definitely plays a role as the stretch is stopped (in the experimental studies) when the participant says its too much.  What happens with long term stretching is that you are able to go farther without there being a dramatic change in tissue qualities.  Meaning we assume that the changes in ROM are due to your tolerance or perhaps habituation rather than a structural change.

The muscle spindle stretch reflex is assumed to not be occurring during end ROM stretching because in these studies they monitor muscle activity.  Meaning, they try to make sure there is no measurable muscle activity that occurs at end ROM.  We assume its just a passive resistance to stretch.  However, it is plausible that there is minor amount of activity that isn’t being picked up and this could be “putting on the brakes”.

 

QUESTION 8: Do you believe there are ways in which passive stretching could actually be beneficial for the body on a musculoskeletal level? If so, how?

ANSWER: Yes.  I think long term stretching is just passive tensile force and tension has the ability to create positive structural adaptations in tissue.  Some (Kubo) have argued that passive stretching can make tendon more efficient.  Others suggest that passive stretching influences muscle stiffness which might be good to balance the stiffness changes in a tendon that can occur with injury.

I certainly don’t view stretching as a negative which I once did.  I think if you argue against stretching you are really not “against” stretching but more pro some other intervention.  So, if you like to stretch and its helpful for you I would encourage you to keep it up. 

THANK YOU AGAIN TO GREG FOR HIS GENEROSITY IN SHARING HIS KNOWLEDGE AND INSIGHT WITH THE YOGA COMMUNITY. I HOPE YOU FOUND THIS INTERVIEW INFORMATIVE AND HELPFUL FOR YOUR YOGA PRACTICE & TEACHING! -JENNI

Learn much more from Greg Lehman on his website here, and follow him on Twitter!


Stretching Misconceptions in the Yoga World

Does stretching make our muscles longer? Does stretching weaken our tissues and de-stabilize our joints? Can “overstretching” give us lax ligaments? Does stretching apply enough stress to our tissues to make them stronger?

There are a lot (a lot!) of claims about stretching that tend to circulate in the yoga community, and not all of these claims are accurate! Did you know?

“Histology” is the branch of biology dealing with the study of the tissues of the body. And from what I can see in the yoga world, many of the claims that we hear about stretching simply don’t jive with what histology/science has revealed about the properties of human connective tissue (including ligaments & tendons) and muscle tissue.

I really appreciated it when the incredibly knowledgeable Greg Lehman stated this quote I’ve featured here during his presentation to us at Jules Mitchell’s 300-hr yoga teacher training that I recently completed. Thank you, Greg!

And for more clarity and some foundational science about stretching, yoga, and which claims are cool and which ones we should definitely retire, check out my new online mini-workshop “How Stretching Affects the Tissues of the Body!”

See you in the workshop for some excellent yoga geeky learning!

Mobility, Stability, & Flexibility: Clarifying Our Concepts in Yoga

I'm more than excited about my newest article in Yoga International that just published this morning! We tend to use the words mobility, stability, and flexibility all the time in yoga, but what do these terms actually mean?

The information I write about in this piece changed my whole perspective on yoga and movement, and I think these concepts have the power to change our yoga community’s entire approach to asana if this message spreads. There is so much value in getting clear on our terms & definitions!

I’m very thankful for the positive feedback I’ve received so far on this piece - I hope you enjoy it if you check it out!

[Microblog] Anatomy Geek Stretching Thought of the Day

ANATOMY GEEK THOUGHT OF THE DAY: We often think of a muscle contraction happening only when a muscle *shortens*. But muscles work just as often as they lengthen - picture your hamstrings and the way they lengthen while they work to control your swan dive into uttanasana (standing forward fold) in yoga. When a muscle works as it lengthens, this is called an *eccentric contraction*, and we move this way all the time in our normal human movements.

One of the core rules we tend to learn in our yoga teacher trainings is that after we've "worked" a muscle or muscle group, we should stretch that muscle group to "balance it out". But because muscles can and do actually contract through all of their ranges (short, long, somewhere in between, etc.), is it skillful to consider the opposite of a muscle contraction a *stretch*? Do these two "balance" each other out? If it turned out that they were not necessarily opposing actions, would this change the way you sequence your yoga classes at all?

Enjoy pondering this one, and feel free to let me know how it goes!

Hamstring Strengthening for Yogis

I recently wrote a blog post that questioned the widespread belief that strengthening muscles makes them "tighter". In the post, I focused on the hamstrings as my main example, because so many people have "tight" hamstrings, but they are generally not recommended to strengthen them due to a belief that this would only make them tighter. Additionally, we spend a lot of time stretching our hamstrings in yoga, but very little time strengthening them.

Can you tell that I think hamstring-strengthening is a good idea, especially for yogis? :)

This video demonstrates one method of strengthening the hamstrings that can easily be included in any yoga class. I love this move and hope you have fun trying it out!

The Easiest Mistake to Make in Backbends

I am sooo thankful to have published a second article in Yoga International! It's all too easy to do backbends in a way that will make your spine mad at you :), and I hope this article will provide lots of helpful info for how to approach these poses in a way that will offer true positive change in your body. Thanks so much for reading, guys!

https://yogainternational.com/article/view/the-easiest-mistake-to-make-in-backbends

In other news, I'm working on a new series of posts for my blog on shoulder mechanics in yoga. I haven't written specifically about the shoulders here yet, so I'm hoping that these posts will help fill in some missing info on this important area of the body. Stay tuned for this and more great movement info to come!

Stretching Is In Your Brain Part 2: What Is The Value Of Flexibility Without Strength?

In Part 1 of my “Stretching Is In Your Brain” series, we looked at some updated information on what happens physiologically inside of us when we stretch. To re-cap, new science is revealing that the widely-held belief that we physically grow our muscles longer during a stretch is inaccurate. Instead, flexibility is controlled by our nervous system, which determines how far it will allow us to move into a stretch based on how safe it perceives our body to be in that range of motion.

As yoga practitioners and teachers, we’ve been treating our muscles as though they are independent entities which we can mold through direct manipulation, but in reality our muscles are just the peripheral, subservient component of a much broader system of communication and control. Let’s explore some of the implications that this major paradigm shift has for how we approach the body in our yoga practice.

 

WHAT DOES PULLING HARD ON OUR TISSUES ACHIEVE?

In the old paradigm of stretching in which we believe that we’re physically pulling our tissues longer like taffy when we stretch, it would logically follow that in order to gain more flexibility, we should simply pull harder and deeper. Wringing oneself deep into a spinal twist or receiving a strong adjustment from a teacher intended to push your range of motion further are common examples of this strategy. But we now understand that flexibility is much less about using brute physical force to grow our muscles longer, and much more about using intelligent communication to suggest to our nervous system that a particular range of motion is safe.

In fact, the “brute force” method of stretching is problematic in multiple ways. When we stretch, our muscles aren’t the only tissues that are affected. Muscles are surrounded by and interpenetrated with fascia, which also makes up the body’s ligaments and tendons. When we move our body into a stretch, both our muscles and our fascia experience the stretch at the same time.

It’s important to understand that fascia has only a set range that it can stretch. Stretching offers many benefits to the health of our fascia, but it won’t change the range of this tissue. This means that after fascia experiences the load of a stretch, only one of two possibilities can happen: 1) it returns to its original length after being stretched or 2) it is stretched too far and is damaged. And that’s it! We don’t make our fascia “longer” when we stretch. And if we pull too hard on this tissue in an effort to elongate it, we will most likely move beyond its ability to withstand the load, which will ultimately lead to injury. As counterintuitive as it may seem, for the health and balance of our structure, we actually want our fascia to be quite “stiff” and “resilient”.

 

BUT HOW MUCH STRETCH IS THE RIGHT AMOUNT?

We understand that stretching intensely does not benefit us, but how do we know where that boundary lies in our body as well as our students’ bodies? Here’s a key rule to use in your practice: when we stretch, we should only move into a range of motion over which we have muscular control. This is because our nervous system feels safest when it senses that we have control over our movement.

Put another way, we don’t want to create flexibility without the strength to support it. If we stretch within these parameters, our practice is likely to contribute to a balanced body that moves well. However, when we stretch into a range in which the targeted muscles cannot function, we are creating excessive mobility (and more than likely hypermobility) that we don’t have the ability to stabilize. 

Hanumanasana, yoga's forward split.

Hanumanasana, yoga's forward split.

To illustrate this point, let’s look at hanumanasana, yoga’s forward splits. If we practiced this pose with the goal of building flexibility within the context of strength, we would only move as deep into the shape as the muscles of our legs could maintain control. Picture it: without using your arms pressing into the floor, you would slowly lower down into your full hanumanasana and then use those very same leg muscles to lift yourself all the way back up (again, without the use of the arms!) This might seem like a superhuman acrobatic feat, but I promise it would be possible if you truly worked to build power at your end range.

My friend Maddy demonstrating gomukasana arms.

My friend Maddy demonstrating gomukasana arms.

Let’s touch in on a few other asanas to see how this “stability at your end range” principle might apply. Padmasana, or lotus pose, is one of yoga’s classic asanas. Most of us use our arms to pull our legs into this shape. We also sometimes use momentum to quickly fold our legs into lotus, but momentum is another method of moving into a range of motion that we don’t have the strength to control. Is it any wonder that padmasana is notorious for tearing soft tissue in many a yogi’s knee joint? Try this instead: without using your arms or momentum, use only the muscles of your legs to fold your feet as close to your hips as you can and breathe there. This shape - one over which your muscles have control - is the correct stability edge for your body. Another great example is ekapadasirsasana, yoga’s leg-behind-the-head pose. If that leg can climb behind your head itself, without the use of your arms, then you’re staying within your excellent strength-at-your-end-range limits. But I have yet to see a yogi who can accomplish such a daunting task! A less obvious pose in which we commonly move beyond our stability edge is gomukasana, or cow-face arms. Many people like to use their opposite arm to help that bottom arm climb higher up the back, but as soon as we interfere with that bottom arm’s own ability to move itself to its edge, we are stretching past our active range of motion and into unsupported mobility.

 

IN CONCLUSION...

I know that so many of us yogis are used to going as deep as our bodies will allow in our poses. Think of the innumerable beautiful photos that yoga teachers have in their portfolios or on Instagram of their bodies looking extremely graceful in a perfectly-executed forward split. (I don’t personally have a photo of myself in hanumanasana, but I certainly have photos of many other asanas in which I’ve moved well beyond my active boundaries.)

The science behind utilizing stability as a container for flexibility is not yet widely understood in the yoga world - and not surprisingly, the number of overstretching injuries in our community is quite high. But as a yoga community, we have to ask ourselves some tough questions: if you have the mobility to move deeper into a pose than your muscles can control, where is that mobility coming from, what is it offering you in terms of how well your body functions, and how many more times can you practice this pose before an injury occurs? What is the value of flexibility without the strength to support it? This is the kind of shift in thinking that yoga needs to make if we want our practice to truly offer the structural health and other long-term benefits like aging with ease that so many yoga practitioners seek.

Stretching is In Your Brain: A New Paradigm of Flexibility & Yoga (Part 1)

In yoga, we tend to place a lot of emphasis on stretching as a means toward more flexibility. But what actually happens in our body when we stretch? Most of us envision our bodies as consisting of play-doh like tissues that we pull on and make longer through stretching, but new science is revealing to us a model of stretching that is much more complex, dynamic, and fascinating than what has previously been imagined. And it turns out that thinking of our bodies in this older “play-doh” like version may be counterproductive and can lead to a number of injuries and structural problems resulting from our yoga practice. In order to keep our wonderful yoga tradition evolving and current, it’s important that we understand this new and fascinating science of stretching and any implications it might offer for our practice and teaching.

 

A NEW PARADIGM OF FLEXIBILITY

Biomechanics-based Restorative Exercise™ teaches a lot of new and eye-opening information about stretching and flexibility that isn’t yet common knowledge in the yoga world. Additionally, the wonderful yoga teacher Jules Mitchell is on a mission to educate the yoga community about the science of stretching. Her recently-completed master’s thesis in exercise science is a comprehensive literature review of the most current scientific research on stretching to date, and it’s full of an abundance of important information for yogis.

Utilizing the innovative knowledge that these resources offer, let’s examine some of our current beliefs about stretching and introduce some helpful ways we can begin to update these beliefs to reflect the newest scientific word on the street.

 

WHAT WE THINK HAPPENS WHEN WE STRETCH

Most people think of their muscles as being either “long” or “short”, and that during a stretch, they are targeting their “short” muscles by physically “lengthening” or “loosening” them. In this stretching paradigm, our muscles are mold-able tissues like taffy or play-doh which we can form into a shape of our choosing by simply pulling or pushing on them. For example, when we fold forward into paschimottanasana (seated forward fold), we tend to imagine that our hamstrings are physically growing longer in that moment of our stretch in the same way that taffy would grow longer if we tugged on both of its ends for awhile. We imagine that when we release paschimottanasana, our hamstrings remain just a bit longer than they were before we did the stretch. And we also imagine that the longer and deeper we hold a pose like paschimottanasana, the longer and looser our hamstrings become.

This stretching paradigm is what most of us were taught in our yoga classes, workshops, and teacher trainings. It’s completely understandable that we might see the body as working like this, but new research is revealing a very different version of the biomechanics of stretching.

 

THE NEW SCIENCE OF WHAT HAPPENS WHEN WE STRETCH

We all know that when we stretch, we experience a feeling of “tightness” at our end range of motion - a sensation that limits us from moving any deeper into the stretch. We have traditionally defined this “tight” sensation as the result of having reached the end length of the muscle(s) we’re stretching. In other words, we pulled on the ends of our muscle until we reached its maximum physical length, and once we hit that boundary, the stretch stopped and we felt the “tightness”. With enough stretching, we could increase the length of our muscle and therefore move further into our stretch with time.

The king of flexibility.

The king of flexibility.

But we now understand that increasing our flexibility has much less to do with the physical length of our muscle tissue, and much more to do with the part of our body that controls and moves our muscles: the nervous system. Our brain and spinal cord, which make up our central nervous system (CNS), are constantly monitoring the state of our body. One of the main imperatives of the CNS to keep our body where it perceives it is safe. Normal movements that we make throughout our day are considered safe by the CNS because it knows and trusts them. But on the other hand, our CNS is not familiar with ranges of motion that we never move into, so it’s much less likely to consider those places safe. When we stretch, if we move into a place that the CNS isn’t familiar with, our nervous system will likely end our stretch by creating a sensation of discomfort at the end range of motion it considers safe. 

For example, if you happen to work on your computer for 8 solid hours a day (and if you don’t take frequent intermittent stretch breaks for your shoulders - hint hint :) ), the CNS becomes very familiar with the arms-forward position that you use while typing and considers that range safe. Then later, if you decide to do a chest stretch in which you take your arm out to the side and then behind you, the CNS doesn’t feel that that movement is safe because you so rarely go there, so it will limit your range very early on in the stretch.

A major takeaway from this new flexibility paradigm is that when we increase our range of motion through stretching, it isn’t because we pulled on our tissues and made them longer. It’s because we visited the edge of our stretch (also called stretch “tolerance”) enough times that our CNS started to feel comfortable there and it began to allow us to move deeper into that range.

 

OKAY, I THINK I’M STARTING TO GET IT, BUT WHY IS THIS IMPORTANT?

It’s definitely interesting and more scientifically accurate to understand this previously-overlooked role that our nervous system plays in flexibility. But whether it’s your nervous system or the physical length of your muscles limiting you in a stretch, why does it matter? Isn’t a stretch a stretch, regardless of the mechanism behind it?

That’s a great question - I’m so glad you asked! The main answer has to do with what tissues are being targeted when we stretch. We often think and talk about stretching our muscles in our yoga poses (i.e. paschimottanasana stretches our “hamstrings”), but in truth our muscles are surrounded by, interwoven with, and inseparable from our fascia. Our fascia is our incredible body-wide web of connective tissue that is literally everywhere inside of us, and it includes our tendons and ligaments. Muscles and fascia are two distinct tissues with different properties, but both are affected when we stretch. And how we choose to stretch, which is based on whether we believe that we’re physically lengthening our muscles (old paradigm) or increasing our nervous system’s tolerance for the stretch (new paradigm), determines how our fascia will be affected during the movement. (Preview for Part 2 of this post: if we’re going with the older “pulling on our tissues like play-doh" paradigm, we’ll feel more drawn to stretching deeper and harder in our poses, which is much more likely to simply damage our tissues than give us the flexibility we seek.)

I’ll elaborate more on this and other important topics, like how we might choose to apply this new information to our yoga practice and teaching, in my next blog post. Stay tuned, guys! And in the meantime, if you’re interested in further reading, check out this awesome article by Jules Mitchell (written for a pretty science-oriented reader). See you for Part 2 soon!