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Quite a Stretch

Stretching science has shown that this extremely popular form of exercise has almost no measurable benefits

Paul Ingrahamupdated

SHOW SUMMARY
Illustration of a woman stretching her hamstrings.

Stretching is a pleasant ritual for many people, myself included. It’s simple, it feels good, and we believe — or hope — that it prevents and treats injuries. For many others, athletes and couch potatoes alike, stretching is also a bit of a drag: a duty that weighs on the conscience, one more thing to make time for. And yet they still do it, counting on the benefits.

Can all these people be barking up the wrong tree? Yes. In fact, stretching is not an important part of fitness and wellness. Stretching’s primary goal — flexibility — does not have any clear value to anyone, not even most elite athletes, let alone the average fitness nut. It’s also easily achieved with other kinds of exercise that are much more beneficial for fitness in other ways: strengthening through a complete range of motion. Most stretching is simply a waste of time, its reputation completely undeserved.

Four other articles go into much greater detail on four major sub-topics, and that is where most of the referencing is. You can think of this article as a “summary” of all the others — which still takes many thousands of words — and the others as the detailed “footnotes” for this one.

But stretching feels good!

You bet it does. Stretching is a waste of time… unless you just enjoy it, of course.

I stretch almost every day — hamstrings, lumbar erector spinae, and especially the deep gluteals are my favourites. I do it because it feels nice, but I don’t believe the habit is doing much more for me than a daily back scratch. I am just as stiff and inflexible and full of “knots” as I have ever been. I play sports the same way with or without it. I still get just as sore, whether I stretch or not.

I am hardly the only person to notice that stretching may not be all it’s cracked up to be, and there’s plenty of science on this.1 This article is a readable review of the key arguments and concepts and some of the most interesting evidence. Warning: you may not enjoy stretching quite so much once you realize how many myths there are about its benefits.

Flexibility has been researched for over 100 years. Its track record is unimpressive, particularly when viewed in light of other components of physical fitness. Flexibility lacks predictive and concurrent validity value with meaningful health and performance outcomes. Consequently, it should be retired as a major component of fitness.

~ Nuzzo, 2020, Sports Medicine

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This isn’t just about static stretching

This is not just about the inadequacies of simple “static” stretching. Many stretching advocates are happy to join me in criticizing simple, old-school static stretching — that is, elongating a muscle and then holding still for a while. They are happy to do that because most of them decided long ago that some other method of stretching actually does work, and that’s where their allegiance lies. They feel no need to defend static stretching.

Unfortunately, there is no clear evidence that any method of stretching is a clear winner for any important therapeutic goal.

For instance, alternately stretching and contracting a muscle is a staple of “advanced” stretching. This is called the contract-relax (CR) method, which is part of a general strategy with the very advanced sounding name of “proprioceptive neuromuscular facilitation” (PNF). However, it’s really nothing fancy: CR just adds contraction.2 It doesn’t increase flexibility any more than static stretching.3 In 2011, researchers compared a normal CR stretch of the hamstring to a modified one without any hamstring contraction (instead, some other “uninvolved, distant” muscle was contracted). The effect of both stretches was the same — a “moderate increase in range of motion,” which is the one thing that stretching will achieve. It didn’t matter if the hamstring was contracted or not — with or without a contraction, the result was the same: a slight increase. This is a major blow to the central claim of CR-PNF stretching.

Things that sound too good to be true … still aren’t.

Some supposedly advanced stretching methods are not really “stretching” at all. There are only so many things that you can change about stretching before it really becomes something else. The classic example is dynamic joint mobility drills — repeatedly moving through a larger range of motion than usual (i.e. swinging your arms in a circle or walking lunges). Should we call that “stretching”? Perhaps. But I say no: although the kinship is clear, it already has its own name, and it’s a movement exercise, not “stretching.”

If an exercise doesn’t involve elongating muscles to the point of feeling significant tension for several seconds at least, it’s not stretching.

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Part 2

Tipping over stretching’s sacred cows

The unstretchables: some muscles are biomechanically impossible to stretch

To begin: anatomy has limits. Strict limits. An owl can rotate its head as much as 270° and you can’t! Owl spines and people spines are different.

Although anatomy is amazingly variable (for some interesting examples, see You Might Just Be Weird) it still works about the same for most people, and there are anatomical limits on all stretches. Some more than others.

Tensile force can not be applied equally to all muscles. Most of us will hit the end of the natural range of motion of the joint long before we’ve stretched anywhere near as hard as you can stretch other muscles. In other words, some muscles are just biomechanically awkward to stretch. I call them “the unstretchables” — a bit of hyperbole, but true in spirit. Although these muscles can be elongated, they can’t be elongated enough to create the satisfying sensation of good stretch.

There are several important muscles and muscle groups that are mechanically impossible to stretch much, including ones (like the quadriceps) that people think they are stretching.4 Even if stretching actually had the benefits that people believe in — which it clearly does not — those benefits would still not actually be available for large areas of our bodies.

This biomechanical reality is spread over the whole topic of stretching like a large, wet blanket. Whatever stretching can do for us, if anything, it has do it within the significant constraints of our anatomy, like a suntan lotion that we can’t apply to our own back. As you read, bear this broad limitation in mind.

For much more detail, see: The Unstretchables: Eleven muscles you can’t actually stretch hard (but wish you could)

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The five popular reasons people stretch (are all wrong)

When asked to explain a stretching habit, many people struggle. They have a hard time articulating clear, specific goals. Everyone just “knows” that it’s a good thing, and they haven’t really thought about why. It’s dogma, practically a religion. When pressed for reasons, most people will cough up a few predictable stretching goals. Here are the four hopeful reasons for stretching that I hear every day:5

  1. flexibility, of course6
  2. warm up and injury prevention
  3. prevention/treatment of exercise soreness
  4. treatment of sports injuries and chronic pain

And a fifth which I only hear occasionally, but it’s still out there:

  1. “performance enhancement” (e.g. faster sprinting)

All of these overlapping goals for stretching have serious issues.

One final reason for stretching gets mentioned surprisingly infrequently. People prefer to give more “technical” and serious-sounding reasons for their stretching, I guess.

  1. it feels great!

This may be the best reason for stretching. 😃 Just ask Murmel:

I stretch because it feels good. Just a couple seconds stretching this-a-way, then a couple more that-a-way, and I’m good to hop. Don’t overdo it! Holding stretches is over-rated.

~ Murmel the bunny, master stretcher

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Stretching for sports and fitness

Most stretching happens in an athletic context, and most of the reasons people give for stretching are sports-o-centric: warm-up and injury prevention, recovery and performance. The more general assumption, usually unstated, is that flexibility is a major component of fitness, on par with strength and endurance.

These goals and beliefs are easy to debunk. (But no matter how effective that debunking, nearly everyone will continue to assume that it’s different for “serious” athletes or athletes who seem to need more flexibility.)

Stretching as a warm-up

You cannot “warm up” your muscles by stretching them: it’s like trying to cook a steak by pulling on it. Instead, the best way to warm up is probably to start by doing a kinder, gentler version of the activity you have in mind (i.e. walk before you run). The metabolic activity involved in muscle contraction does literally warm up your muscles, an inevitable side effect of all the activity that actually makes warm up effective for injury prevention.

Nothing about static stretching is more clear than this failure. A huge 2011 review of all the research found “overwhelming evidence that stretch durations of 30-45 seconds … imparted no significant effect” and even some evidence of harm.7

Warmup works

A large study of girls’ soccer teams showed warming up can cut injury rates by about a third. Notably, the warmup that was studied, FIFA’s “11+” warmup, did not include stretching!

Most professionals actually gave up on static stretching as a warmup. But I still see it all the time in the wild.

The best way to prepare for any intense activity is just to start easy and steadily dial-up the intensity.

Stretching for soreness (or otherwise enhance recovery)

The deep soreness that follows a hard workout (“delayed-onset muscle soreness” (DOMS) or sometimes just “post-exercise soreness”) is very uncomfortable and it does impair performance. Many people believe that stretching can prevent or relieve it. But this definitely doesn’t work.8 Basically, nothing touches DOMS — nothing anyone has ever claimed as a treatment for it has actually passed a fair scientific test (see the DOMS article for more about all that).

In 2016, decades after this faith first got entrenched, science finally coughed up a specific reason why it might be based on something: evidence that stretching reduces inflammation in connective tissue.9 But there are many problems with leaping to that conclusion. Whatever minor effect stretching has on inflammation, it does not add up to a DOMS cure.

Stretching to prevent injury

Why would stretching prevent most injuries? There’s no clear mechanism for it. There are a couple ideas that seem a little intuitive, but musculoskeletal medicine is where intuition goes to die. It’s all much more complicated than it seems.

The failure of stretch to prevent injury isn’t fresh news. The evidence about this has been quite clear for at least 20 years. A 2014 review of exercise therapy for injury prevention in the British Journal of Sports Medicine was completely negative about stretching10 — even though the authors were obviously a bit too optimistic about everything else!11 “Consistently favourable estimates were obtained for all injury prevention measures except for stretching.” Ouch.

There may be some injury prevention powers to stretching — muscle strains seem like the most likely candidate. But I can think of several Sports Injury Prevention Tips that are probably more effective/efficient than stretching!

Stretching as a part of rehab for injury

That which prevents injury often treats it as well, and vice versa, and that’s the basic rationale for stretching as a treatment for injury. Except that stretching doesn’t prevent much injury, if any, so it’s unlikely that it can treat it either.

There are some elaborate rationalizations for stretching as a treatment, chiefly that it corrects something: some “imbalance” that is allegedly a risk factor for injury. But this kind of thinking has been called the “trap” of corrective exercise, a trap for pros and patients.12 (You can read much more about “the trap” in my main strength training article.)

Most of rehab is (or should be) just “load management” — that is, doing not too much or too little at each phase of recovery, taking baby steps back to normal function. And stretching obviously doesn’t have much to contribute to load management.

The most reasonable reason to stretch for rehab is to preserve or restore range of motion. While there is no doubt that stretching can improve range of motion, it’s unlikely that stretching protects or restores ROM any more than gradual return to normal activity levels.

Everyone and every case is different, and I can’t rule out the possibility that specific stretching is useful for certain specific rehab situations. But those are the exceptions that prove the rule, if they exist at all.

Stretching can actually cause injuries

Cartoon of a man stretching his neck alarmingly far to one side. His neck is a spring that is breaking.

Ironically, stretching can actually cause some of the injuries it is thought to prevent or treat. Although, stretching is mostly a safe activity, especially if practiced with a modicum of caution, there are (at least) four potential types of stretching hazards:

  1. Mild impairment of performance.
  2. Traumatic injury (sprains and strains) from over-stretching.
  3. Traumatic injury due to pathological vulnerabilities (mainly the hypermobility disorders, Ehlers–Danlos syndrome etc).
  4. Aggravation of unexplained body pain.

For more about these risks, see 5 Main Reasons Athletes Stretch… All Flawed. And here’s the story of my own ill-fated attempt to treat some neck pain with stretching: Stretching Injury: How I almost ripped my own head off! A cautionary tale about the risks of injury while stretching.

Stretching to enhance performance

The most flexible athletes are not necessarily the most successful.

~ Flexibility, by William Sands, p. 389

You don’t hear this argument for stretching as often as your hear the others. And yet it comes up, especially with runners, and with athletes who play sprinty team sports. It’s a common practice to stretch when you’re off the field. The habit is mostly rationalized as an injury prevention method, but many of those athletes will also insist that it enhances their performance.

Why? How does stretch make some a better soccer player? One version: the muscles “spring back” from the stretch and make them run faster! Um, no — it’s actually a little bit the opposite. All other things being equal, the athlete who didn’t stretch is going to leave you behind! A variety of studies have shown this effect.13 I wouldn’t take the danger too seriously — it’s not a big effect — but it certainly emphasizes the lack of benefit: if anything, it swings the other way.

For much more detailed treatment of all of these topics (including a lot more of the science), see:

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Stretching for pain (and for pleasure)

Stretching has an extraordinary reputation for being good for aches and pains, but it’s not clear that stretching deserves this honour.

Stretching as therapy mostly rides on the coat-tails of stretching’s indomitable popularity for other purposes, especially the nearly universally accepted idea that flexibility is a pillar of wellness and fitness, on par with strength and endurance — an idea that is a bit dubious when you consider stretching’s conspicuous failure to deliver most of the benefits people expect of it.

But if stiffness is like an itch, stretching is how we want to scratch it! And the symptom of stiffness is thoroughly tangled up with chronic pain. The pleasant sensations of stretching seem directly relevant to the symptom of stiffness, like ice on a burn. It feels inherently valuable to people, and I am not knocking “pleasure”!

But not everything that feels pleasant is actually therapeutic, and there are many, many kinds of pain. Even if stretching is good for some of them, it probably isn’t good for all or even most of them.

So what does stretching work for? Anything? And if so, why? I will have some good things to say about it, but there’s also plenty of debunking ahead.

The usual reasons stretching is considered therapeutic

The anecdotal evidence that stretching “works” for miscellaneous body pain and stiff and aching muscles is substantial. (So is the anecdotal evidence that it can backfire.) There is also some scientific evidence suggesting that stretching is helpful for common stubborn pain problems, such as neck and back pain, but it’s also a complicated, incomplete, underwhelming mess, and there are also popular stretching practices that are clearly a waste of time. For example, stretching hamstrings to treat back pain is not effective., because there’s no correlation between back pain and how the hamstrings are behaving in the first place.14 And yet that belief probably accounts for at least 50% of all the stretching people do for back pain!

People who feel stiff and tight usually assume their range of motion is limited by literally short muscles, but this is rarely the case, despite how it feels. Stiffness isn’t the same as being inflexible; they aren’t even really related. Most stiffness is a sensation, a symptom, a kind of mild pain with movement rather than an actual limitation of movement. Even hypermobile people often feel stiff!

There could be reasons why stretching is good for pain that we don’t understand, or are only just barely starting to understand. Some of the causes of stiffness that stretching might be more relevant to: inflammation, trigger points, and contracture. But — spoiler alert — there’s literally not one clear promising example of stretching as effective medicine for anything painful. Not one.

Stretching, inflammation, and aging

If there’s one thing most responsible for the feeling of needing to stretch, it’s probably the most common cause of aches and pains: “inflammaging.” Chronic low-grade inflammation that gradually escalates over the years, for all kinds of poorly understood reasons, and mostly manifests as stiffness and minor aches and pains, for a long time. Our brains are more reluctant to allow free, quick movement of sore tissues.

But can we stretch that feeling away? Is stretch anti-inflammatory? “Taking the edge off” sometimes would be enough to explain the reputation stretching has for relieving stiffness and soreness, but it’s extremely unlikely that stretching has have substantial anti-inflammatory effects — not enough, and not lasting enough, to make a real difference. Inflammaging is mostly a steamroller that stretching cannot really touch. Fitness in general is probably much more “anti-inflammatory” than stretching specifically. Once again, stretching is probably overshadowed by the other components of fitness.

Stretching out “muscle knots”

There is one kind of soreness that is common and might be responsive to stretching: the stiffness and aching associated with those sensitive spots in muscles commonly known as “muscle knots” or trigger points. The problem is… no one really knows what these knots are or how to treat them.15 The conventional wisdom is that they are micro-cramps, and that sounds like something you might be able to stretch out… except in practice it could well be like trying to untie a knot in a bungie cord by pulling on it. You’re just going to stretch the hell out of the bungie cord on either side of the knot. If it works at all, it probably mostly only works on the milder cases that don’t matter much in the first place.

But it’s more likely that we just don’t know how trigger points work, and that stretching is mostly irrelevant to them.

Is stretching good for tendons? Can it align their fibres?

Muscle and tendon, although they are distinct tissues, blend together quite seamlessly. Much of what we think of as mucle is an extension of tendinous tissue, and vice versa. It’s impossible to draw a line where tendon stops and muscle starts, and if stretching doesn’t do much to muscles, it probably doesn’t do much to tendons either.

And so most likely a positive effect of stretching on tendons is minimal or nil.

The specific notion that tendon stretching will “align” its fibres is a particularly dubious and overly optimistic concept. Tendons are well nigh impervious, rupture only with extreme forces (and/or when already compromised), and change only in response to long term “just right” overloading. For a mere stretch, collagen fibres don’t line up obediently any more than they already are — and tendons have impressively well-aligned microscopic orderliness to begin with.

Stretching does feel good, and maybe that is a kind of pain-killer

If stretching is mostly irrelevant to pain and injury, why is it that I feel like I have to stretch or I’m going to seize up like an old piece of leather? Because it probably is actually doing something! It’s just probably not doing what you thought it was doing. And we don’t really know for sure what it is doing. If we are intellectually honest, we simply have to admit that.

There could well be a stew of genuine but subtle physiological benefits — like the heart rate regulatory effect — plus almost certainly some good placebo, too. I just don’t know. And based on the research to date, no one else does either.

And, then again, there may actually be real physiological benefits to stretching — just not the usual ones that get tossed around.

Stretching for contracture: Thumbs down to static stretching as a treatment for seizing up

“Contracture” is the unlovely process of muscle and other soft tissues seizing up in response to neurological problems or prolonged immobilization. This is pathology, and the tissue changes, for the worse.

Could long, intense stretches be an effective prevention/treatment for contracture? Perhaps the only viable option. It seems to make sense, especially given that we know stretching can indeed make us more flexible. And stretching always gets the benefit of the doubt, whether it deserves it or not, and it seems to make sense that stretching would be a cure for contracture.

But common sense fails again, as it so often does. It just doesn’t work.16 Pathologically seized up tissue cannot be meaningfully elongated. So what’s happening when healthy people seem to get flexible?

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Stretching for flexibility

Stretching has a place of honour in athletics, sports medicine, and fitness — it is an activity everyone loves to love — and yet it is arguably the most over-rated thing you can do with a body. Most of the reasons athletes stretch — warming up and injury prevention, recovering from soreness, enhancing performance — do not stand up to scientific scrutiny.

There is really only one effect of stretching that seems to be clear and (almost) uncontroversial: it does actually increase flexibility. Even just plain old “static” stretching, and not even that much of it. Just putting tension on a muscle will do the job.17

For whatever it’s worth, people do seem to be more flexible when they stretch regularly for a while. Meaningful improvement is elusive, but it can be done. The phenomenon is widely observed, and seems to have been confirmed by experiments, several of which will be cited below. But less than you’d think at this point in history! There’s hundreds of studies of anything these days, but not this.

So, you almost certainly can get more flexible “for whatever it’s worth,” but … what is it worth? Exactly? When you try to spell out it out, it’s surprising how quickly things get a bit “um, er, well.”

Is flexibility actually even a benefit?

What exactly are you planning to do with your flexibility?

The American College of Sports Medicine believes that flexibility is “important in athletic performance (e.g., ballet, gymnastics) and in the ability to carry out activities of daily living.” It’s a “major component” of fitness, along with body composition, cardiovascular endurance, muscle endurance, and muscle strength. They recommend 2–3 days of stretching per week (2–4 repetitions of multiple stretches per day).18

Personal trainers certainly buy into it. About 80% of American trainers prescribe static stretching — for all the reasons, but mainly for the flexibility.19

The value of flexibility for the average Jack or Jill

Hardly anyone actually needs to be more flexible. Most people have a normal range of motion — that’s why it’s normal! Unless you are specifically frustrated because you lack sufficient range of motion in a joint to perform a specific task, you probably don’t need to be more flexible.

Even abnormally poor flexibility is usually no big deal, as long as you are otherwise healthy. There just aren’t many functional limitations caused by being super stiff that actually matter much.

For flexibility to matter, we have to identify a common and meaningful functional limitation that can be overcome by increasing range of motion. And those are rare. It just doesn’t and shouldn’t matter to most people, most of the time.

If inflexibility is good enough for Eliud Kipchoge, it’s good enough for you. As of 2018, Mr. Kipchoge was the world’s fastest marathoner… but the man cannot touch his toes!

Stretching barely registers on any measure of health and function. More flexible people do not die less or fall down less as they age. They don’t have clearly higher quality of life (a tough one to measure, but it’s been done). They don’t have less back pain or injuries, and in fact they may have more. They don’t have lower blood pressure, resting heart rate, cholesterol — those markers of fitness are much more strongly predicted by weight and endurance.20

Flexibility also isn’t linked to the other components of fitness: flexible people cannot lift more, run farther, or slip through narrower cracks.

Stretching dosage for flexibility: intensity, frequency, duration, technique, and controversy

Hold it right there! For how long exactly, though? And how often? How hard? What works best? Is 5 seconds of light stretch every other day for a couple weeks enough? Probably not. The evidence suggests that holding a stretch for 15 seconds is better than 5… but only a little bit.21 The bottom line:

In 2011, a nicely done experiment by Marshall et al showed that regular hamstring stretching substantially increased range of motion in normal university kids.22 Specifically, after “a 4-week stretching program consisting of 4 hamstring and hip stretches performed 5 times per week,” their range increased about 16˚ or 20%. That’s a real result from a sane stretching dosage. For whatever it’s worth.

But there’s astonishing diversity of expert opinion on this, and fussy and time-consuming techniques are routinely recommended. The idea of a “correct” dosage (or any aspect of technique) is mostly a fantasy. And yet, somewhere between “not nearly enough” and “way too much” there is probably a sweet spot.

Getting hard core: more extreme efforts undoubtedly do produce more extreme results

Acrobats, gymnasts, yogis, contortionists, and martial artists have clearly been pushing the limits for centuries, sometimes achieving uncanny mobility. But the value of flexibility even for these athletes can and has been questioned in recent years. “Athletes usually don’t require extreme ranges of motion,” writes Todd Hargrove,23 “but rather extreme control at the end of relatively normal ranges of motion.”

And that is achieved primarily with strength training… not an insane stretching regimen with real risks.

Is this a good idea? This is an “oversplit.” Regularly doing this kind of thing will certainly make a person flexible … but not “healthy.”

Is this child gymnast going to be more flexible? Oh, yes, I think she will be! Will she perform better? Not necessarily: she might be better off doing strength training at the limits of her range — which will not only increase her range, but improve her control at the limits of her range. Is she going to be “healthier” for it? Blatantly not. And she has a middle-aged guy sitting on her back … and that’s just gotta suck.

Tolerance versus plasticity

Several explanations for increased flexibility from stretching have been proposed, and none have clearly panned out. A 2010 paper in Physical Therapy reviews them all in great detail, and the full text is free.24 It’s not light reading, but there are some fascinating highlights. The two main possibilities are the incumbent and an upstart:

  1. Plastic deformation: our tissues change in response to tissue. We get literally “longer” (or more extensible).
  2. Sensory tolerance: our nervous system learns to allow greater movement. The original limitation was an arbitrary, neurological imposed limit, not a physical one. “There is no spoon.”

The debate rages on and the truth is probably somewhere in the middle. Scientific evidence continues to accumulate. But the upstart — stretch tolerance — probably has a lot to do with flexibility gains. Meanwhile, Team Plasticity remains large and devout, and they can point to some research to support their position.

Increased flexibility may simply be an increased tolerance for the discomfort of excessive muscle elongation.

Let’s get neurological

If you do some upper body stretching, your lower will get a little more flexible. Not much, but enough to measure in a controlled test.25 But that’s the only effect — which suggests that it’s due to an increase in tolerance of stretch, and that’s all. It’s one of many clues suggesting that stretch tolerance is the secret sauce in flexibility.

In other words, muscle (probably) doesn’t change, especially in response to an average stretching regimen … but our willingness to elongate it probably does. This is clearly supported by some research.26

Strong clues that stretching is a way of teaching the nervous system that it’s okay to stretch a little further. This might explain the flexibility feats of yogis and martial artists, whose hypermobility might well be dangerously dysfunctional if it were attributable to plastic deformation.

For vastly more detail than this, see Stretching for Flexibility.

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Part 3

So … is stretching good for anything?

Responses to some common objections and ideas about stretching (and some of my own)

How about this? It’s good for your heart!27 “Enhanced vagal modulation.” That’s fairly straightforward good-news science about stretching. (And yet I’ve never heard anyone say they were stretching for heart health.)

It’s not surprising that movement would have some systemic regulatory effects, but it’s nice to see some corroboration of that common sensical notion, and it’s also nice to know that perhaps just stretching did this (to the extent we can learn anything from a single study). If true, it makes for a nice point in favour of a general stretching habit and yoga, “massaging with movement,” and probably even massage itself. It may have a lot to do with why massage feels good.

But stretching is probably not good for the reasons most people are stretching — not much good, anyway, and certainly not much in any ways anyone has figured out how to measure.

Undoubtedly, some specific stretching techniques are good for specific purposes … but quite different from the stretching goals that most people actually have in mind, if they have any clear goals at all. My concern is not that stretching itself is useless, but that people are stretching aimlessly and ineffectively, to the exclusion of evidence-based alternatives, such as a proper warm-up or mobilizations.

I don’t believe that stretching is any more generally useful for people than it is for cats — you do it when you get up in the morning for a few seconds and then you’re off to the sandbox. That feels good — it’s stimulating and enhances your body awareness, it scratches some simple physiological itch, and that’s fine and dandy. But for most people, most of the time? As a time-consuming therapeutic exercise ritual? Stretching simply has a lousy effort-to-reward ratio.

In the next few sections, I will respond to some of the common objections and questions that readers often have.

“But don’t people just need to be taught how to stretch properly?”

No one actually knows what a “proper” stretch is. There are no accepted standards in stretching technique (not even close), no method that is clearly superior, no way to know what’s right, no definition of success and no accepted method of achieving it.

The pretentious subtext of all preaching about stretching technique is always the same: stretching is only valuable if you “know what you’re doing.” And so a number of experts stay in business by advocating a stretching method or rationale that seems to trump all the others. Unfortunately, none of them can agree with each other.

The nice thing about standards is that there are so many of them to choose from.

~ Andrew S. Tanenbaum

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“But isn’t yoga all about stretching? And Yoga has lots of benefits, doesn’t it?”

Yes, it is, and yes, it does — but probably not the benefits that people normally attribute to stretching. Even flexibility is suspect.28 Same with qigong, and the martial arts are full of stretching techniques — some of them appropriated from the modern Western fitness tradition, and others inherited from traditional practices. I advocate this kind of stretching elsewhere in my writings. So what’s the difference?

The difference is in intention. The intention of stretching in the context of good qigong, yoga or martial arts is to focus the mind, to stimulate vitality through a combination of mental and physical exercise. The intention is everything — without the intention, you might as well not bother with these activities.

Most westerners stretch without the foggiest notion of this underlying complexity. Stretching is generally stimulating to body awareness, of course: but that awareness is unsophisticated and incidental, rarely involving any insight more complex than “ooh, that muscle sure is sore.” Without education about intent — without a rich philosophical context — the value of stretching in yoga is just as uncertain as it is in any other situation.

And stretching in yoga also involves some risks. Too often people perceive yoga as an entirely wholesome and harmless activity, but in fact over-stretching injuries and muscle strains are actually common. As with dancing or martial arts, there are many ways to hurt yourself practicing yoga.

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So stretching is good for … stretching?

That’s a reasonably safe theory about how flexibility works. But it is not easy to achieve significant stretch tolerance — it takes weeks of diligent effort, quite a bit more than most people ever actually push themselves to achieve. Many people probably believe that they have achieved this, but it’s mostly wishful thinking, and the huge majority have only scratched the surface of their potential flexibility during brief phases of their lives.

More to the point, what’s the point? We already know that stretching does not do all the basic stuff we used to hope it was doing, especially injury prevention. Is it good for anything else?

There is no known benefit to greater flexibility, except for:

In short, stretching appears to be good for … more stretching. Oh, and of course:

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About Paul Ingraham

Headshot of Paul Ingraham, short hair, neat beard, suit jacket.

I am a science writer in Vancouver, Canada. I was a Registered Massage Therapist for a decade and the assistant editor of ScienceBasedMedicine.org for several years. I’ve had many injuries as a runner and ultimate player, and I’ve been a chronic pain patient myself since 2015. Full bio. See you on Facebook or Twitter.

Part 4

Appendices

More reading

Other interesting reading relevant to stretching:

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What’s new in this article?

This article had a long history of unlogged updates — a decade or so — before I finally started logging them in 2015. Updates shown here are the most recent only.

Aug 7, 2020 — Reorganized: Split this mega-article up into four smaller ones. Three major sub-topics were exported to new pages. This article now provides a high-level summary, plus coverage of a few miscellaneous and minor subtopics that don’t fit anywhere else. There are now a total of 9 articles on PainScience.com specifically devoted to stretching.

April — More content: Added some examples of stretching being rejected by elite athletes. [Updated section: Stretching for sports and fitness.]

January — Science update: Added an important example, stretching the hamstrings for back pain, with a few relevant references. [Updated section: Stretching for pain (and for pleasure).]

2019 — Reorganized: I’ve shuffled and renamed many sections, plus a bunch of editing, to reflect new priorities for the article going forward: a more comprehensive review of all stretching sub-topics, but especially stretching as a component of injury rehab and treatment for chronic pain. Several significant changes are planned for 2019.

2018 — Expanded: Added more the nature of soreness and stiffness, and the relevance of stretching (or lack thereof). [Updated section: Stretching for pain (and for pleasure).]

2017 — Science update: Cited and discussed implications of anti-inflammatory effect reported by Berrueta et al. [Updated section: Stretching for pain (and for pleasure).]

2016 — Rewritten: Complex and thorough modernization and other improvements. [Updated section: Stretching for pain (and for pleasure).]

2016 — Revised: Reorganized the list of reasons for stretching, officially including “it feels good.” Updated the summary of stretching for trigger points. [Updated section: The five popular reasons people stretch (are all wrong).]

2015 — Upgrade: Added table of contents.

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Notes

  1. Nuzzo JL. The Case for Retiring Flexibility as a Major Component of Physical Fitness. Sports Med. 2020 May;50(5):853–870. PubMed #31845202 ❐

    This is the first of many citations in this article, but it’s also one of the best and most general, and highly recommended reading for professionals. It is like a more scholarly and formal version of this article.

  2. Some readers will sniff at this and say that CR is still not “advanced” stretching, but it is certainly still widely used, taught, and touted as being better than humble static stretching. I see trainers using it at the gym all the time. Patients can go for physical therapy pretty much anywhere in the world, and there’s a good chance the therapist will do a whole bunch of CR stretching with them, while charging about a buck a minute.
  3. Azevedo DC, Melo RM, Alves Corrêa RV, Chalmers G. Uninvolved versus target muscle contraction during contract: relax proprioceptive neuromuscular facilitation stretching. Phys Ther Sport. 2011 Aug;12(3):117–21. PubMed #21802037 ❐
  4. Other major examples include: masseter and temporalis, the suboccipitals, the thoracic paraspinals, latissimus dorsi, the gluteals, the foot arch muscles, and the IT band (of IT band syndrome fame). Some of these muscles can, sort of, be stretched. But all of them are limited to a moderate intensity stretch at best (e.g., the gluteals), in most people, most of the time, using reasonably accessible methods.
  5. I spent a decade in clinical practice as a massage therapist, routinely asking my patients about their stretching beliefs and habits, among many other things. These days I am a full-time writer on these topics with a global audience, so I heard vastly more about stretching from readers by email than I ever heard from my patients back in the day. I have a great bird’s eye view of popular opinions about stretch. Professionals send me a lot of mail as well, so I get a lot of exposure to their opinion’s. Are they more educated about stretch? You’d sure hope so, but that hasn’t really been my impression, to be honest — it really seems like everyone is just repeating things they heard other people say. Professionals just hear and repeat even more.
  6. Flexibility is routinely suggested both as a reason to stretch, and a reason why stretch works for other purposes. These are quite different things. Both will be considered in detail below.
  7. Kay AD, Blazevich AJ. Effect of Acute Static Stretch on Maximal Muscle Performance: A Systematic Review. Med Sci Sports Exerc. 2011 Jun 8. PubMed #21659901 ❐ Researchers looked at more than 4500 studies before choosing about 100 to look at more carefully. The found “overwhelming evidence” of “no significant effect,” and that is certainly no surprise for anyone who had been watching stretching science over the years.
  8. Herbert RD, de Noronha M, Kamper SJ. Stretching to prevent or reduce muscle soreness after exercise. Cochrane Database Syst Rev. 2011;(7):CD004577. PubMed #21735398 ❐

    Does stretching help either before or after exercise to reduce soreness? Nope. This large review of eleven small scientific studies, and one huge one, wrapped up with a clear thumbs down:

    The evidence from randomised studies suggests that muscle stretching, whether conducted before, after, or before and after exercise, does not produce clinically important reductions in delayed-onset muscle soreness in healthy adults.

    The evidence was “low to moderate,” with “moderate to high” risk of bias, which means most of the researchers were probably hoping to find that stretching does help DOMS … but even with that likely bias, they still didn’t find what they were looking for.

    The big study was technically positive, finding an average drop in soreness of four points on a 100-point scale, which is basically meaningless. The variation between the results for individuals is undoubtedly greater than that.

  9. Berrueta L, Muskaj I, Olenich S, et al. Stretching Impacts Inflammation Resolution in Connective Tissue. J Cell Physiol. 2016 Jul;231(7):1621–7. PubMed #26588184 ❐ PainSci #52915 ❐

    In a previous experiment, these researchers claim to have found evidence that stretching successfully treated inflammation and pain in rats. In this follow-up experiment, they looked more closely at the biology, measuring markers of inflammation: inflammatory lesion thickness, neutrophil count, resolvin (RvD1) concentration. They believe this shows a “direct mechanical impact of stretching on inflammation-regulation mechanisms within connective tissue.” It’s intriguing science for sure, but replication in humans is needed before we get too excited about it.

  10. Lauersen JB, Bertelsen DM, Andersen LB. The effectiveness of exercise interventions to prevent sports injuries: a systematic review and meta-analysis of randomised controlled trials. Br J Sports Med. 2014 Jun;48(11):871–7. PubMed #24100287 ❐ PainSci #53226 ❐
  11. They thought strengthening looked good, but based their very positive-sounding conclusions on only four studies of dubious quality and relevance.
  12. Tumminello N, Silvernail J, Cormack B. The Corrective Exercise Trap. Personal Training Quarterly. 2017 Mar;4(1). PainSci #52905 ❐

    The authors decisively but gently tip over the most sacred cow of personal training and therapy: corrective exercise, which is grounded in the assumption that there is something in-correct about patients — fragile, weak, or uneven — which must be fixed by sufficiently expert and precise exercise prescription. Exaggerating the importance of defect-correction is actually dangerous for the patient (nocebic): “When clients are told such things about themselves from an authority figure (as they might be during some corrective exercise evaluations), that this potentially makes one’s clients less resilient and more prone to injury and pain.” Translation sans diplomacy: *stop #%&^ telling patients they are fragile and weak!*

    The corrective exercise trap is also about overconfidence in the value of allegedly advanced rehab exercise, when the evidence is overwhelming that corrective exercise is no better than general exercise. “The danger here” — the trap! — “is that many fitness professionals might end up making their training process more about a formalized evaluation procedure and less about good personal training.”

    (See more detailed commentary on this paper.)

  13. Beckett JR, Schneiker KT, Wallman KE, Dawson BT, Guelfi KJ. Effects of Static Stretching on Repeated Sprint and Change of Direction Performance. Medicine & Science in Sports & Exercise. 2009 Jan 5.
  14. Hori M, Hasegawa H, Takasaki H. Comparisons of hamstring flexibility between individuals with and without low back pain: systematic review with meta-analysis. Physiother Theory Pract. 2019 Jul:1–24. PubMed #31317831 ❐
  15. Ingraham. Trigger Points on Trial: A summary of the kerfuffle over Quintner et al., a key 2014 scientific paper criticizing the conventional wisdom about trigger points and myofascial pain syndrome.  ❐ PainScience.com. 4049 words.
  16. Harvey LA, Katalinic OM, Herbert RD, et al. Stretch for the treatment and prevention of contractures. Cochrane Database Syst Rev. 2017 Jan;1:CD007455. PubMed #28146605 ❐ PainSci #52742 ❐
  17. Freitas et al “Stretching interventions with 3- to 8-week duration do not seem to change either the muscle or the tendon properties, although it increases the extensibility and tolerance to a greater tensile force.” This is just one of many examples of similar research.
  18. American College of Sports Medicine. ACSM’s guidelines for exercise testing and prescription. 10th ed. Philadelphia: Wolters Kluwer; 2018.
  19. Waryasz GR, Daniels AH, Gil JA, Suric V, Eberson CP. Personal Trainer Demographics, Current Practice Trends and Common Trainee Injuries. Orthop Rev (Pavia). 2016 Sep;8(3):6600. PubMed #27761219 ❐ PainSci #52598 ❐
  20. Nuzzo JL. The Case for Retiring Flexibility as a Major Component of Physical Fitness. Sports Med. 2020 May;50(5):853–870. PubMed #31845202 ❐
  21. Roberts JM, Wilson K. Effect of stretching duration on active and passive range of motion in the lower extremity. Br J Sports Med. 1999 Aug;33(4):259–63. PubMed #10450481 ❐

    Another (small) study to determine if stretching for five or fifteen seconds can make a difference in range of motion of the joint. It concluded: “These findings suggest that holding stretches for 15 seconds, as opposed to five seconds, may result in greater improvements in active ROM. However, sustaining a stretch may not significantly affect the improvements gained in passive ROM.” In other words, the returns diminish quickly.

  22. Marshall PW, Cashman A, Cheema BS. A randomized controlled trial for the effect of passive stretching on measures of hamstring extensibility, passive stiffness, strength, and stretch tolerance. J Sci Med Sport. 2011 Nov;14(6):535–40. PubMed #21636321 ❐
  23. Hargrove T. Playing With Movement: How to explore the many dimensions of physical health and performance. 1st ed. self-published; 2019. p. 148
  24. Weppler CH, Magnusson SP. Increasing muscle extensibility: a matter of increasing length or modifying sensation? Phys Ther. 2010 Mar;90(3):438–49. PubMed #20075147 ❐ PainSci #55283 ❐
  25. Behm DG, Cavanaugh T, Quigley P, et al. Acute bouts of upper and lower body static and dynamic stretching increase non-local joint range of motion. Eur J Appl Physiol. 2016 Jan;116(1):241–9. PubMed #26410819 ❐

    In this study, range of motion and strength were tested in the upper body after static stretching in the lower body, and vice versa. Passive range of motion was modestly improved, which is nifty, but not active ROM or strength, suggesting that “enhanced stretch tolerance was likely the significant factor,” as opposed to a mechanical or neural drive mechanism.

  26. Blazevich AJ, Cannavan D, Waugh CM, et al. Range of motion, neuromechanical, and architectural adaptations to plantar flexor stretch training in humans. J Appl Physiol (1985). 2014 Sep;117(5):452–62. PubMed #24947023 ❐

    For this study, several people stretched their calf muscles twice per day for three weeks (each session consisted of 4 stretches of 30 seconds). They were compared to people who did not stretch. Measurements included changes in muscle and tendon mechanics, muscle activity, and spinal motoneuron excitability. The non-stretchers didn’t change; stretch training “elicited a 19.9% increase in dorsiflexion range of motion (ROM) and a 28% increase in passive joint moment at end ROM.” However, the ROM improvement was not explained by changes in the muscle structure: “Thus, increases in end ROM were underpinned by increases in maximum tolerable passive joint moment (stretch tolerance).

  27. Farinatti PT, Brandão C, Soares PP, Duarte AF. Acute effects of stretching exercise on the heart rate variability in subjects with low flexibility levels. J Strength Cond Res. 2011 Jun;25(6):1579–85. PubMed #21386722 ❐

    … multiple-set flexibility training session enhanced the vagal modulation and sympathovagal balance in the acute postexercise recovery, at least in subjects with low flexibility levels. … The present results suggest that stretching routines may contribute to a favorable autonomic activity change in untrained subjects.

  28. Many readers have pointed out that experienced yoga practitioners are flexible, especially the older ones. For instance, T.G. writes, “In my yoga class, the older people are way more flexible than the younger ones.” It may be that training has made them more flexible, but not necessarily. A perpetually neglected explanation for the flexible-yoga-oldster phenomenon is that people with natural gifts of flexibility like the activity and stick with it, because we humans enjoy almost anything we’re good at … and the less flexible tend to drop out. I’m not saying this is how it is — I truly don’t know — just that it’s the kind of explanation that tends to get neglected. We need to consider such counter-intuitive, inside-out explanations that are, perhaps, less comforting to our biases. Even if there is a training effect, it’s extremely likely that it’s only part of the reason those folks are more flexible, and that’s something most “huge fans” of stretching have simply never considered.