Reasons Not to Stretch | Hacker News Reader

Reasons Not to Stretch

well.blogs.nytimes.com

126 pointsglenstein91 comments

The title is misleading, to say the least.

I occasionally suffer from lower back pain. From experience, tight hamstrings seem to be the cause. If I regularly stretch my hamstrings, I am without back problems. If I stop stretching, then, after a few months, I'll suddenly develop severe back pain. It's happened 3 times already, so I'm seeing a pattern.

So I guess my point is: stretching can help in other areas; it just may not help you improve one specific aspect of your performance. It can keep you injury-free.

The basic point made is that pre-exercise stretching decreases power and may decrease stability. Sports scientists have been finding this in a number of studies for some time.

Post-exercise stretching, or regular therapeutic stretching, is not what they're talking about.

Which is what the GP meant: the title is misleading. Which is more important than you might think, because later those titles end up inside the folk knowledge.

Your hamstrings are too short and pull on your lower back. To fix short muscles stretching is great. If your muscles aren't already short then stretching isn't very useful.

(Post-workout stretching can help prevent your muscles from ever becoming short)

I think that the title is only somewhat misleading. When I think of "stretching" I think of the classical static stretching which is increasingly coming under fire.

I grew up calling dynamic stretching "warm ups".

I think this is probably true for most people, but I admit that it may depend a lot on the fitness environment one grew up in.

The article actually means static stretching. I grew up knowing the difference and used dynamic stretching[1] pre-explosive events and static stretching at off-times.

[1] Fire hydrants, Scorpions, Iron Crosses, Skipping, etc.

Title is misleading. The article's main focus is on pre-workout stretching.

I run several times a week, sometimes up to 20km at once and post-run stretching is most definitely a must-have.

Have a cite? This article indeed concentrates on pre-exercise stretching, but I've heard similar things about post-exercise.

Definitely need studies now to prove post stretching provides benefit, otherwise it seems like just another Holiday Inn statement

You could have talked to Olympians XX years ago about their pre-whatever-sport and heard them say stretching beforehand is a must-have

Yep.

What's the Holiday Inn statement?

Additionally, this article only considers /static stretching/, which is far less helpful to me as a runner than /active stretching/: leg swings, kicks, or arm circles.

I agree. Skipping a post-run stretch is a big mistake. (Just take the stretching easy after longer runs, like a marathon. Then your muscles are weak and intensive stretching can damage them.)

I avoid most pre-run stretches, but find that both static and dynamic stretches of my ankles pre-run are helpful. There are specific studies that also support this.

Depends on your reason for doing so. For instance if it's to avoid muscle soreness that has been disproved. There are two major reasons for stretching.

One: It increases the amount you can stretch so if you need to be able to stretch far for some reason it will help with that.

Two: It feels great. I stretch a lot for this reason.

As far as I know there are no other proved benefits to stretching.

+1 for post-workout stretching.

It is nothing new, it was suspected for a while by many studies.

Personally I do not practice stretching. It initially started as an experiment - as in "if I don't stretch I should get hurt ?", "ok I want to test this and see precisely how much!", ie to try to evaluate the marginal value of stretching.

So far I have yet to see a negative consequence of not stretching (ie increased risk of injury, even if anecdotal experience is not very helpful)

Preparing oneself to movement is something else - you do not just immediately do something point blank, at least personally I don't - I try to "get a feeling" of the movement by performing it once or twice without any load.

Neurologically, for a computing equivalent, this acts like caching - your cerebellum is a cache for your physical movement equations (ie activate this muscle at this time, then t microseconds later this other muscle, etc)

So just performing the movement like a mime preloads the equations into the cache - basically, it makes you more efficient!

What worries me however is the amount of people you meet (ex- PT) who insist on you stretching, and who may not take no as a response - as if the refusal to stretch was just an indicative of a lack of knowledge, and therefore the superiority of their position, and that by some "moral imperative" they had to impose you the truth.

I always find that weird.

Just as with everything in life, wisdom of the crowd may not be indicative of the best way to achieve a given result.

EDIT: for those talking about post effort stretching, there is less evidence about this. Some says it prevent too much acidity from accumulating in the muscle (lactic acid), yet this same parameter in studies on weight lifters has been show to increase muscle mass and volume. Yes it may cause pain and prevent you from performing similar activity the next day, but if your goal is to maximize the health benefits on the time spent, and not just maximize the distance run or the amount of time spent running, it might be a better idea to avoid stretching, "do with" the pain, and skip practicing until you have less pain ie skip up to a week.

Overtraining exists, and just compare marathon runners to sprinters. Who visually seems the "fittest"? I'd rather look like a sprinter than a marathon runner, and also the risk of injury seems higher in distance running.

Many exercises are simply not safe if your muscles are tight or you lack the flexibility to do them properly. Swimming, weight lifting, most sports come immediately to mind.

I'd say that not stretching and not warming up are two different things.

I'd agree that there are certain movements that you really don't want to attempt without a certain amount of prerequisite flexibility, which often requires a certain amount of static stretching to achieve.

However, overall flexibility seems to be a longer term condition than just pre-workout stuff. Stretching post-workout or daily but disconnected from pre-strenuous exercise seems to make you more limber/capable of movements that require more flexibility to safely/correctly do. In particular, most of the serious dancers I know stretch(ed) a huge amount (often daily) and also did fairly strenuous dance (often daily), but the static stretching and actual exercise were highly removed from each other. There are also a lot of movements in most types of dance that are either impossible or dangerous without a certain amount of prerequisite flexibility.

Pre-workout warmups are also seem important for avoiding injury: if your muscles are tight/tense and you throw yourself into a strenuous exercise, my experience and everything I've heard says you're going to have a bad time. From personal experience, but every time I've injured/hurt my muscles it was during exercise where I hadn't warmed up or had done a bare minimum of warmup.

Source: Mainly personal experience and what I've seen as a former competitive swimmer (high school varsity, butterfly, fairly serious), former dancer (modern; not serious, but I know some people who were part of larger dance companies), and someone who is currently involved in fairly intense bodyweight strength training (think gymnastic conditioning).

I'm a competitive powerlifter. Your statement isn't quite true. The best way to acquire the flexibility for weightlifting movements is to perform those movements. If you aren't flexible enough to squat to the correct depth, the solution is to squat as deep as you can, and let that serve as the stretch.

The accepted wisdom amongst my crowd is that the appropriate warmup prep is some dynamic movement to raise the body temperature, like rowing or biking, followed by practicing a given movement at progressively higher weights, until you are ready for the work sets.

I've never heard a weightlifter recommend static stretching before training.

I do powerlifting, though not competitively, and I can't agree with you that the best way of acquiring the flexibility is to do the movements. I struggled for nearly a year to improve my depth on my squats and deadlifts that way.

It took <3 months to fix once I saw a physiotherapist that gave me some dynamic stretches to do in between my workouts. I increased my squats from a paltry 2/3 of my body weight and reduced range of motion to 1.5x my body weight at full range of motion in 6 months from I started doing the stretches, after having been stuck without any improvement for many months. I've kept increasing since.

I don't doubt that doing the movements may work for some, especially if you have reasonable flexibility to start with, but it certainly didn't work for me, or at least did not give noticeable results over a very long period of time, whereas it took less than 2 weeks from I started doing my stretches until I saw substantial improvements.

I absolutely agree with you that pre-exercise stretches is not recommended for lifting weights, but that does not mean stretches are not useful.

Can I ask specifically what kind of dynamic stretching you were doing? I have chronically tight hips that leave me unable to perform "adequate" squats - poor range of motion and balance on the squats, and lack of power. I'd love any tips you have to offer.

Not much, actually. Swinging a leg at a time back and forward, and left and right, as well putting a foot at a time forward and doing a pike stretch down to that foot and right back up again, walk a couple of steps and doing the other foot (like #2 here, but a foot forward at a time: http://www.wikihow.com/Get-a-More-Flexible-Back).

Strict good-mornings are also quite good once you have decent amounts of flexibility. Strict = make sure your back stays arched, push your butt as far back as possible, with a slight bend in your knees, and hinge/bend at the hips. Essentially you should feel it in your thighs and butt and not elsewhere; if you start losing the arch in your back, you've pushed as far down as you can go, go back up and repeat. It's more important to keep form than forcing yourself as deep as possible - you'll get better depth soon enough.

I've later incorporated some static stretches including several of the one in the wikihow link above, but the ones above were enough to see dramatic improvement when done a for a few minutes a couple of times a day.

I also do asian squats regularly (so effectively sitting down in a squat position, unloaded, for as long as I an do - a few years back I wouldn't be able to get up without intense pain from that position, if I got into it in the first place...) and feel that helps me increase the depth I get into (and it's made it so much easier to play with my young son, to be able to effortlessly squat down to him instead of ruining my knees...).

That's good to hear, thanks. I have always had very good flexibility, so it was never an issue for me. I do stretch my hamstrings and IT band sometimes, and static stretching certainly has it's uses.

Glad to hear dynamic stretches worked for you!

Yeah, static stretching makes you too loose for powerlifting. You need to be able to achieve extraordinary tightness to maintain proper posture under the bar.

I find that foam rolling, lacrosse ball rolling, and band tension exercises help the most before powerlifting. My knees don't seem to track properly for the squat unless I foam roll my legs and glutes beforehand. It makes a huge difference.

Light static stretching is good for relieving tension and tightness after the workout. But before, foam rolling is much much better for making you flexible without losing force and tightness.

I second this. While I'm not a powerlifter, I do lift regularly. Two years ago I stretched before doing anything, including a warm up. Sometimes I would be in a rush and skip the stretching. After I noticed that it made no noticeable difference, I dropped it and just did my regular warm up (run a mile). Now, before doing anything really heavy, I'll just do the movement with little weight or only body weight. I've been able to lift more and seem to have less muscle fatigue as a result.

You definitively want your muscles to be tight for weight lifting. But you also want the flexibility to do the full range of motion.

What you absolutely don't want is to stretch before the exercise to loosen up the muscle - you're not suddenly going to gain much extra range of motion, but you will reduce your ability to control the movement.

Stretching after (our outside of) your regular workouts, on the other hand, can be useful.

The article presents studies which contradict that exact claim.

What about stretching in between?

Like you, I abandoned pre-workout and post workout stretching without any ill effect.

I often stretch in between though, and have found it can be effective in relieving chronically tight muscles. For example, I had a 'permanently' tight hamstring that I fixed with 30 seconds of targeted stretching per day for about a month.

I use it for either imbalances, or for soreness from weight-lifting. However, I'm less certain of the usefulness of what I'm doing compared to my hamstring fix.

Those stretches were provided by a physiotherapist, and worked very well. My previous hamstring stretches had achieved nothing. The ones he gave me were generally dynamic stretches.

I can't comment on stretching but I've found foam rolling (or other such myofascial release) to be the greatest thing ever for relieving tight muscles. Have you tried that?

Yes. I think I need to learn a few different positions, as I can not hit some muscle groups as well as others.

I've also used a theracane to great effect on my shoulders.

To add to drexel, foam rollers or rumble rollers are great. I've also got an orbital buffer I use on myself that, as funny as it sounds, works amazingly well.

Excellent remark : like you, I keep some minimal in-between stretching (and I pay much more attention to drinking sweet cold water or soda during effort)

I do that ministretch when I "hear" or "feel" cracks that just should not occur in a given position or movement. It's as if my ankle was trying to sing the me the song if its people :-)

Lately I have noticed I could also do without this last remnant of stretching if the movements could be scheduled to alternate opposite muscle groups, ie make each routine put load on muscles which generally oppose (bi/tri ceps) and concentrate your training on a different set each day,

Exemples: investe in the biceps in your training today, it passively stretches the triceps, the do the triceps etc. so that at the end on your training everything is stretched even if you did not do stretching.

It's not "real" stretching - just the idea that curls should go hand-to-hand with skull-crushers.

I want to express how incredibly odd it is (and yet fitting for HN) that you're analogizing a fairly simple physical concept in terms of computing.

It's not called "warming up" because of the minor uptick in body heat.

Not a criticism; just remarking on the oddity because it amused me.

One caveat for those who are pushing the big 5-O (and trust me, sooner or later, you all will be): the title of the article should have been "Reasons Not to Stretch before Exercise." Stretching for the purpose of counteracting the loss of elasticity of the tendons that comes with age is a different matter. It's like "the other flossing": it's well-known that it should be done, but compliance is spotty.

I'd phrase it slightly different. Working through the full range of motion is important for avoiding loss of range of motion. That doesn't have to mean static stretching.

Like a couple people have said, this is nothing new--it's an affirmation at most. But what also is missing is that it is completely reliant on the individual. Warmups are RELATIVE to YOU, the athlete.

I played 3 varsity sports--soccer, swimming, and track--throughout my 4 years of high school but made sure that I did a dynamic stretch of MY OWN before getting into any stretching/exercise with the rest of my team. I stayed healthy throughout high school. When I got to college, I decided to play ultimate frisbee and made the A team. I became lazy and started stretching with the team--the coach had us do a relatively rigorous dynamic stretch. I wasn't a fan but went along with it (again, I was lazy). About 5 weeks in, I pulled my hamstring badly and it took me about 6-8 weeks to fully recover. I don't want to jump to the conclusion that not doing an individual dynamic stretch was THE reason for my injury, but it definitely was a large contributing factor. From the time I came back until now, I make sure to do my own dynamic stretch before getting into any exercise, light or intense--it works.

WHY?

The whole point of stretching is really to get your muscles moving and to be comfortable. Only I can decide when I feel I am ready to go...and only you can decide when you are. So do what you feel is best for you first, then immerse yourself in activities that your peers or team is doing. And I promise, this will not be held against you as doing something that the team is not. Hell, I was the captain of my swimming and soccer teams for my junior and senior years. If you're helping yourself, you're ultimately helping the team--especially in this context.

Warmup and stretching are orthogonal to each other. Warmup is important, stretches pre-exercise are not and may be harmful in terms of injury risk for that workout. Doing dynamic stretches overall is good improving your flexibility, though. Overall you might very well have done yourself more good than harm, but you'd likely do yourself even more good by warming up a different way and doing your dynamic stretches at a different time.

"Getting your muscles moving" does not require a stretch, you can keep your movements well away from pushing your range of motion.

This is old news. E.g. "Stretching Scientifically" by Tom Kurz published IIRC some time in the 1980's discusses this in detail. Static stretching ahead of an activity is counter-productive and increases risk of injury. What you need to do before an activity is warm-up != stretching and that warm up should be customized to your activity. Stretching after the activity is a better idea though you also need to pick the right stretches, combine with strength training, and it all depends on your flexibility and sport.

Another thought, as someone who sits all day (really need a standing desk!) and practices Karate and a little Yoga I definitely recommend that people who sit all day do some sort of stretching and other activities to counteract the effects of prolonged sitting...

Being a fairly competitive runner in my spare time (38:40 10k, 1:26 half marathon), I'd like to weigh in:

There are two different kinds of flexibility involved in running or exercise in general. 1) Static flexibility: Responsible for your ability to bend over and reach down to your toes. 2) Dynamic flexibility: Remember those drills where you try to kick your heel as high as possible? From standing, bringing up your heel as far as possible is difficult, but even while you're jogging slowly, it's much easier.

While it is important to maintain a good balance between static and dynamic flexibility, the latter is more important during exercise. Consider doing a dynamic warmup before your exercise [1], rather than doing static stretches. The reasoning behind this is that static stretching reduces the tension within your muscle fibers and leads to decreased strength and stability during exercise. After exercise, thorough static stretching is fine. While the effect on lessening muscle soreness is somewhat doubted, stretching muscle fibers after exercise prevents your muscle fibers from shortening and aids in restoring flexibility and tension for your next exercising session.

TL;DR: Rule of the thumb: Pre exercise -> dynamic warm-up; post exercise -> static stretching

[1] http://www.youtube.com/watch?v=djDqDDQl-Y4

I thought this was well understood for a while now.

Has anyone advocated static stretching prior to exercise or sports in recent times? I'm in college now, but ever since I can remember, dynamic warmups were done, and static stretching was only post-exercise.

'"Now, you listen to some of these so-called sports-medicine experts today--shit! It's just shtick. It's just something else to sell. Warming up," he scoffed, adjusting a red ascot fitted neatly into his jumpsuit, "warming up is the biggest bunch of horseshit I've ever heard in my life. Fifteen minutes to warm up! Does a lion warm up when he's hungry? 'Uh-oh, here comes an antelope. Better warm up.' No! He just goes out and eats the sucker. You gotta get the blood circulating, but shit, does the lion cool down? No, he eats the sucker and goes to sleep. And that," he concluded, folding his arms into a variation of the pose, "is the truth."'

- Jack LaLanne on stretching, from Outside Magazine

This is a horrible metaphor. The lion would undoubtedly perform at a higher level if he warmed up properly prior to going out on a hunt. There are, however, tons of other reasons lions haven't evolved to 'warm up' before going hunting.

Don't the lionesses actually do the hunting?

When I ask my dog, "Do you want to go for a walk?", she stands up, does a looong stretch of her back and rear legs, then shakes her coat.

Cats, including big cats like lions and tigers, statically stretch on a regular basis.

Studies like this make you question how much of our folk knowledge and wisdom is false. I stretch before and after my daily runs under the assumption that this has been reducing my injury risk. From these results, I should stop wasting time on pre-run stretches.

Hopefully we'll see more studies built by attempting to support or reject the folk wisdom we've assumed throughout our lives that haven't been subjected to rigorous scientific scrutiny through controlled experimentation. This could be the foundation of very impactful scientific careers.

One challenge would be communicating and disseminating results of such studies to the public. Many times (especially where diet and lifestyle choices are concerned) the results would run counter to large and entrenched commercial interests with enormous marketing budgets and expertise at influencing consumer choices. Countering this influence as an individual researcher or cash-strapped government agency isn't trivial, to say the very least.

It's not just folk wisdom. A significant portion of our medical wisdom, what many doctors pass off as science, has little basis in fact. My wife's pregnancy was eye opening on this regard.

Doctors are one of the few groups who don't think they need to justify themselves. When pressed doctors typically respond with what is essentially "trust me, I'm a doctor".

What unjustified advice did your wife get?

When she was pregnant, my wife did a lot of research into what the studies actually said about the impact of caffeine, alcohol, breastfeeding, etc, on fetal and childhood development. The way doctors and nurses talked about it, you'd think there were conclusive studies showing major impacts from even low levels of caffeine and alcohol consumption, and not breastfeeding for up to a year.

I think the breastfeeding debate is a great example. The studies showing any non-trivial advantages are tenuous, and often fail to detect any statistically significant advantage at all. At the same time, doctors completely and thoroughly fail to analyze these decisions in a rational cost/benefit way. Breastfeeding is a tremendous burden on career women. If not breastfeeding enables a woman to get back to work sooner, get less behind on her career progression, etc, then there is a monetary benefit to not breastfeeding, a very concrete one one that must be balanced against the tenuous and uncertain costs of not breastfeeding.

Same thing for drinking during pregnancy: http://www.huffingtonpost.com/peggy-drexler/-a-loaded-questi.... I recommend reading the Peggy Drexler article, it's wonderful.

Same thing for caffeine: http://www.webmd.com/baby/news/20100721/moderate-coffee-drin.... Note that: 1) 200 mg is about two and a half red-bulls, and 2) exercising, something which doctors recommend to pregnant women without reservation, has been linked to similar increases in risk of miscarriage as heavy caffeine consumption.

When it comes to pregnant women, the medical communities recommendations are wildly unscientific and highly irrational.

It's not just that. You're going to have to contend with the resistance of people you're attempting to dislodge conventional wisdom from.

To quote Alistair Fraser, "I find teaching of science fairly easy. I have no difficulties with science education; my difficulties are with science reeducation. If I can teach something about which the students have never heard, I find that they generally both welcome and understand it. It is when I have to teach them about something that they have already learned incorrectly, that I start to identify with Sisyphus."

http://www.ems.psu.edu/~fraser/BadScience.html

>Studies like this make you question how much of our folk knowledge and wisdom is false

If you really start to try making hypotheses and then test them objectively, and keep an eye on your track record, it starts to become surprising that folk wisdom ever turns out to be true. A maddeningly small minority of plausible hypotheses are actually true, and confirmation bias is strong. If you haven't already, you should probably just go ahead and cut your confidence about everything you think you know in half - especially if it isn't backed by hard science.

> I stretch before and after my daily runs under the assumption that this has been reducing my injury risk. From these results, I should stop wasting time on pre-run stretches.

Have you been injured? Have you seen and/or felt a decrease in fitness due to your stretching routine? If not, I wouldn't change much of what you are doing due to a blog post or this study...

The problem with all these studies is that those that are on the bleeding edge of Strength and Conditioning research are the coaches out in the gym working with athletes and soccer moms. Sadly, no matter how many lives these people change for the better, their methods are discounted due to the lack of scientific rigor.

I've been a strength and conditioning coach for 5 years now and I get very little value out of any of the articles and studies published by NSCA, despite their clout. I continue to pay my dues for access to the information.

You do have a great point though about how well trenched the conventional "wisdom" is in these areas and the large commercial influence that controls these studies through funding or not funding a program.

These studies did not look at injury risk, they looked at top-end strength and power.

I'm not saying the studies are wrong, just that one must read very carefully when evaluating the applicability of this sort of statistical research. Muscular performance has many aspects--strength, power, endurance, range of motion, elasticity, resistance to injury, energy storage, lactic tolerance, etc. off the top of my head. Plus these all change over time in response to how you exercise, eat, stretch, etc.

It's worth looking at "active isolated stretching" for an approach that is well-regarded in distance running circles and is an alternative to the "static stretching" that this article is referencing: http://www.runnersworld.com/injury-treatment/active-isolated... . It's easy to learn and is a sort of middle ground between stretching and the active warmup suggested by the article.

Stretching is absolutely important in certain situations -- context matters. E.g. if you sit all day and have back pain, in general you should be doing psoas (hip flexor) stretches, and should not be doing back stretches. The article is mostly right that you should stick with light stretching and exercises on a daily basis, but for tightness and imbalances that need to be actively corrected, stretching is the way to go.

> But even more interesting, they also reported that they felt less stable and more unbalanced after the stretching than when they didn’t stretch.

I find it somewhat suspect that the study doesn't say they in any way tested the athletes stability or balance, just that they took them at their word. It sounds suspiciously like it might even be the Dunning-Kruger effect in action.

Another thing which is suspect is that these studies are done on very short time-frames. It's quite common that things that are beneficial in the long-term result in short term problems. I'd be very interested to see some multi-month or even multi-year studies, especially studies working with more dynamic metrics (for example, taking populations of sports teams and comparing win/loss numbers.)

In general I think stretching is important in a variety of ways for physical activity, and these studies are all focusing in on some very narrow artificial activities I don't personally do very often. I guess this validates that I don't stretch before getting on my bicycle, but it doesn't really speak to stretching before dancing or anything other than strength tests that hit very specific muscles for a short period.

Laugh if you will, downvote if you must, but, as with many things, I trust to my dogs' opinion in the matter: they stretch before physical activity, and so do I (for other reasons of course too).

I don't dispute the short-term performance gains by not pre-stretching, but is there a long-term cost? With performance gains in any system, there are usually trade-offs. If I were in a race to win a million dollars, you can bet your ass I'm not stretching beforehand based on all this research, but what about before my light daily jog? I feel all rickety sometimes if I don't.

I'd be interested in a history of stretching, specifically before physical activity. Evolutionary precedent has a way of shedding light on these sticky questions. For example, what kind of warm-ups or stretching did cavemen do before a mammoth hunt?

This is irresponsibly poorly presented. Pre-exercise stretching doesn't reduce the chance of injury and slightly reduces performance of muscles. Not terribly surprising.

Stretching for fitness and flexibility - e.g. yoga - is essential.

Do yoga. Don't do yoga before you play hockey.

Babies stretch; cats and dogs stretch. It's not all harmful, or useless, to stretch--just do it when you feel like it. This research is really just about systematic static stretching, done whether you want to or not.

And maybe I didn't read it carefully, but I didn't see anything in there about preventing injury. I have naturally tight hamstrings; stretching them out before exercise makes them feel better and less likely to cramp or get pulled. It probably lowers my performance, but I'm not racing, I'm just trying to have fun and stay in shape.

I wonder how much of this effect (muscles weaker after stretching) is because stretching tires the muscles, as it will certainly require energy to execute a static for a minute or so. If the effect is similar to other forms of muscle use, it would be unsurprising. If it weakens muscles in a unique way, that seems more interesting.

I stretch quite a bit because my muscles get tighter over the time, in particular from working at the computer.

My dog stretches upon returning to activity from rest. A form of dynamic stretching, just a few seconds.

It wouldn't be due to simple muscular tiredness. Studies on weight training show that local muscular fatigue can largely dissipate within minutes.

I'd place my money on a CNS phenomenon.

Central nervous system? As a guess would you say such an effect might not be that bad beyond the immediate lowering of strength? Not a long term effect?

One hypothesis of how stretching increases flexibility is that it's a long term learned effect on the central and peripheral nervous system.

If you try PNF stretching -- where you push back against the stretch -- you'll be surprised how much further a stretch can go. And that's purely a nervous system phenomenon, some of it not reaching the CNS at all.

I've found the dynamic warm-ups to be very helpful. I use variations of the following prior to running:

http://www.runnerspace.com/video.php?do=view&video_id=84... http://strengthrunning.com/2011/07/the-standard-warm-up-vide...

I do stretch a few problem areas after I run (hamstrings, for instance).

Dynamic before, good long stretch after (mainly because it feels good). Stretching to increase flexibility is also a little misleading, everyone at every age is flexible, but we have inbuilt safeguards where our brain sets a maximum range of movement and tells the muscles to restrict movement beyond that. When you stretch to increase flexibility what you're actually doing is resetting the brain's idea of what's normal rather than stretching muscles or tendons.

Yes that's indeed the conclusion of the article that one should prefer dynamic warm up instead of static stretching. For long efforts it says that post stretching help to recover (The other takeaways of the article can be found here https://tldr.io/tldrs/515d3491207be0f11e0007bf/reasons-not-t...)

I used to think stretching was stupid. Then I got old. Now I find that stretching reduces soreness the next day after a run. Certainly others have had the same experience?

The title of the article is too generic - he is talking of static stretching before a workout which is largely useless for weight lifting or power lifting styled workouts. In those regards the author makes a fair point. Static stretching before lifting weights affects stability. Plus it does nothing to warm up the major muscles that are used when lifting the weight.

Stretching does not reduce soreness, it increses it. Soreness is due to microtears in the muscle fibers caused by exercise. Stretching can also cause microtears.

The only way avoid getting sore is to increase your load progressively, or stay at a load you're accustomed to.

Being flexible might help with soreness in a sense that the soreness is less noticable: for example if you have very tight hamstrings, and they are sore, any movement is likely to make that soreness noticable. If, however, you are quite flexibly you might have to stretch your hamstrings, by bending at the waist, before you actually notice that you are indeed a bit sore after yesterday's workout.

I'm basing this on my own experiences from running and military training; stretching before exercise is pointless .. but stretching after very vigorous exercise does help a lot with reducing cramp and the stiff feeling you get after waking up.

However I've also found that if I exercise at around the same level most days I can cut out stretching completely. And when I start to wind the amount of exercise down, I can feel when my muscles need stretching again.

Did our ancestors stretch before hunting? I doubt it.

Did they floss?

Well... has flossing been shown to be useful for human health?

ETA: quick Google, found one meta-study. Results:

"Trials were of poor quality and conclusions must be viewed as unreliable. The review showed that people who brush and floss regularly have less gum bleeding compared to toothbrushing alone. There was weak, very unreliable evidence of a possible small reduction in plaque. There was no information on other measurements such as tooth decay because the trials were not long enough and detecting early stage decay between teeth is difficult."

http://summaries.cochrane.org/CD008829/flossing-to-reduce-gu...

So, pretty weak evidence, though perhaps mostly from lack of trying. It can't be considered as important as brushing.

Then again, how do we know brushing is important? Time to find some other studies...

Flossing supposedly helps fight gum disease, halitosis (by removing some of the gunk stuck between the teeth that toothbrushes can't get at) and other mouth afflictions.

How much of that "research" and "science" is actually funded by Colgate, Johnson and Johnson and the like I don't know though...

Can't speak for the rest of the world, but at least 99% of India doesn't floss. Just sayin' :-)

Despite the American oral fixation, flossing is not all that popular over here. The guilt about not flossing is, however, huge.

Do they have good teeth?

I suspect our diet has changed considerably since our ancestors' time. So all the extra sugars and processed food we shovel in our mouths is bound to affect our oral health in ways that might necessitate additional cleaning measures (e.g. flossing).

Hard to know:

https://www.google.com.au/search?q=lion+stretching&hl=en...

This is much more analogous to "stretching" by reaching to the sky, or by arching one's back, than to the static muscle stretches discussed in the article. This natural kind of stretching feels good (no need to educate people), which is evidence it's been selected for, and seems to concentrate more on joints than muscles.

Why do we have to consider everything they did optimal?

Of course they did. Primates stretch all the time--just go to the zoo and watch for a while.

When I was playing water-polo (10+ years ago), we always did some mild stretching (a couple of moves repeated maybe 10x) after a 20-min jog session and some body-weight exercises, right before getting into pool. We were said that trying to stretch "cold" muscles was just destructive.

It's curious to see this brought up as novelty.

My wife learned about the book Natural Flexibility

http://www.amazon.com/Natural-Flexibility-Risk-Free-Alternat...

by Charles Kenny, M.D., and has found it helpful for maintaining injury-free flexibility for a variety of exercises.

Ctrl-F injury

So they ignored the single reason that stretching is recommended, and found that stretching has other side-effects.

Thanks, I guess?