Practical Science on Movement and Pain

Should You Stretch a Sore Muscle?

Brain vs. Brawn

What is the first thing you do when a muscle is tight and sore? Stretch it right? The point of this post is to say: don’t do that. There is a good chance you will just make the problem worse, not better.

Structure vs. Function

Before getting into why, I first want to define some terms which distinguish two concepts that are commonly used by physical therapists and trainers- structure and function. Structure means the actual physical hardware that we use for moving around – in short, the bones, muscle and connective tissue. Function means the ability to sense and control the physical structure, which is governed by the nervous system. You can think of structure as the hardware of the body and function as the software of the body.

So why do we care about the distinction? If you want to fix a problem with your computer, you might need to know whether to make changes to the software or the hardware. The same is true with the body. So imagine your hamstring feels stiff and sore when you run or bend over. Is this a problem with the hardware or software? Structure or function?

Deforming the structure

Let’s take the structural approach first, because this is the way we tend to think. From this perspective, the diagnosis is simple and mechanical. The hamstring feels stiff and sore simply because it is too short! The solution is also simple and mechanical. The hamstring can be made physically longer by stretching it. At first these length changes are elastic and therefore temporary, but if you stretch long and hard enough (and I mean longer and harder than anyone would ever want to) then it might become somewhat permanently longer by adding in some extra actual physical stuff (in the form of more fascia or extra contractile units) in the chain of muscle. So, now we have a longer hamstring. Have we solved the problem?

This depends on many things of course, but my guess is that we have made it worse. Let’s now look at the functional perspective to understand why stretching might not have been a good idea.

The nervous system rules

It is important to remember that the nervous system has complete control over how the hamstring feels and moves. The hamstring by itself is just a piece of meat. It is the nervous system that decides whether the hamstring will shorten or lengthen, and whether it feels stiff or painful when doing so. If you took a drug to take the nervous system out of the equation, such as a general anesthetic, you would be left with a hamstring that feels no pain and is far more flexible than you would imagine.

We should also remember that the main priority of the nervous system is to protect the body from tissue damage occasioned by falls, accidents, or other movements that could aggravate or cause injury, such as stretching your hamstring too far. Accordingly, we can safely assume that if your hamstring feels stiff and sore, the nervous system has concluded that stretching it is threatening to the safety of the body. The pain and stiffness are essentially protective mechanisms – ways to discourage you from lengthening it outside the perceived range of safety.

Why might the brain be concerned about lengthening the hamstring? There are endless possibilities. The most obvious would be that there is some existing tissue damage in the hamstring (maybe slightly torn and inflamed muscle tissue) that will be aggravated by a stretch. Or maybe the hamstring itself is fine, but it needs to be tense in order to protect the knee, which has been lacking in stability and coordination since an injury several years prior. Or maybe the hamstrings are tight to prevent certain movements in the hip or low back which the nervous system fears, avoids, or maybe has just forgotten how to make.

There is probably no way to know which of these factors is the true cause of the tight hamstring. But all of them have one thing in common – the nervous system is concerned that stretching the hamstring will cause damage. Therefore, in each case, we would expect that aggressive stretching of the hamstring will likely cause the threat level to rise even further, which will in turn cause even more pain and tightness in the hamstring. This is the problem with the structural approach – it treats the hamstring like a mindless piece of meat when in fact it is part of a living breathing nervous system that is trying to protect itself.  The result is that a brute force stretching approach to a tight muscle is likely to make the problem worse, not better.

So what would a better solution look like? Again, the possibilities for a successful intervention are endless, but each one would have one critical factor in common – the solution would somehow reduce the level of threat that the nervous system perceives in regard to lengthening of the hamstrings.

Functional strategies

With this in mind, we can devise some strategies. First, avoid movements that cause tension, stress or discomfort, such as … stretching the hamstring.

Second, realize that the nervous system will feel less threat in regard to a movement if it has more movement options and greater movement skill. For example, if the knee and low back are more coordinated, the hamstrings don’t have to be on lock down all the time to protect them. How do we get the knee, low back and other joints to become more coordinated? I have discussed some ways in previous posts, but I can summarize here by saying that you should explore as many movement possibilities in your body as possible, in a slow and mindful way that is non-threatening. Movements that are novel, curious and playful will turn on the nervous system’s ability to process information and learn. If you move while in pain or discomfort, the nervous system has no interest in repeating the new painful movements, only in finding out ways to prevent them from happening again in the future.

So, is stretching the hamstring always a bad idea? I think it’s probably never the best option but it sometimes can lead to a good outcome if done in a way that intelligently targets the nervous system instead of ignoring it. For example, PNF style stretching uses various techniques to “trick” the nervous system reflexes into allowing greater range of motion. Research shows that PNF is the most effective stretching technique to improve ROM (assuming for some reason you would care about ROM).

You might also gain benefit from stretching if you stretch in a very gentle, relaxing, and mindful way. Maybe you could also add in a supportive and nurturing environment, and perhaps some eastern spirituality, bamboo and incense, and other stuff that calms the nerves of white people. This is called a yoga class, and it can be an effective way to reduce pain to the extent that it reduces threat. If on the other hand, you approach your yoga class from the structural perspective, by, say, trying to deform your tissues into the approximate shape of Gywneth Paltrow, you can expect pain. So, take it easy in that power bootcamp core strength hot yoga class. Your nervous system might not like it.

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22 Responses to Should You Stretch a Sore Muscle?

  1. Glenn says:

    Interesting, as always, Todd.
    Could you help clarify the difference between PNF stretching and the PIR PFS approaches?

    • Todd Hargrove says:

      Glenn,

      Thanks for stopping by. PIR and PFS are I think Janda’s and Lewit’s names for stretches. Post isometric relaxation and post relaxation facilitation. I can’t recall the details but they are all basically the same as PNF and lots of other names for stretches as well. All of them use the following elements in different combinations or sequences: Stretch, contract the agonist, contract the antagonist, iso hold, stretch more, relax. I don’t really do any stretching so it all looks the same from where I’m sitting. What they all are basically getting at is reducing the level of threat associated with the stretch by getting the CNS familiar with the extended position and aware of how to get back quickly and safely. If I really needed to get some ROM like get into the splits, I would use one or more of those techniques to get there. Pavel’s Relax into Stretch covers most of these tricks as I recall.

  2. Glenn says:

    Ah, thanks. I have Pavel’s ebook but haven’t gotten around to reading it yet. Somewhat unrelated follow-up, Do you know Thomas Myers’ “Anatomy Trains”? Any thoughts on it?

  3. Todd Hargrove says:

    Yes I know Anatomy Trains. I think its very well written with a a lot of good ideas, pictures, insights. Myers is a sharp guy. However, I think it is essentially a mesodermal as opposed to ectodermal approach. In other words, it analyzes movement and pain problems and tries to solve them in terms of the structure of the mesoderm, as opposed to the function of the ectoderm. I think that is generally a mistaken approach as explained in the above post. That being said, I think his mesodermal analysis is basically sound, except that it fails to include some key structures that mediate structural tension across joints – the nerves. My nerve mechanics series of posts discusses this issue a little.

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  8. jenny says:

    your article helps me…thanks

  9. greg says:

    I have one incredibly stiff hamstring. i haven’t injured it. it feels frozen stiff? stretching does not seem to loosen it there is no pain just discomfort from the tightness. Why??? i am totally fit and healthy everywhere else.

    • Todd Hargrove says:

      Greg,

      I don’t know exactly why your ham is stiff, but I think we can safely guess (barring some structural problem) that your CNS for some reason is threatened by the idea of it lengthening. You can think of the stiffness as a protective mechanism. A stiff ham might be protecting the low back, or the hip capsule, or is part of bracing for a fall because balance in the feet or elsewhere is poor. My recommendation would be to try some mobility drills for joints nearby and progressively further away and then reassess the stiffness. You might notice differences immediately after mobility drills. Good luck.

  10. [...] with some more pain. Perhaps the person then thinks, “well no pain, no gain” and then stretches further. (This is especially likely if the person is in a Bikram yoga class, the person is male, and the [...]

  11. great article todd, thanks.

  12. Alfredo says:

    Todd.

    I have a weird observation here… I have noticed that very often, mostly when i sleep, my hamstrings cramp up. Needless to say that it is excruciating. I jump out of the bed “jack-in-the-box” style and the only way I can stop it is by stretching he affected area…

    What do you think?

    • Alfredo,

      That has happened to me before too. Not fun!

      Cramping remains a mystery I think. Fatigue seems to be a factor in a race setting, but the “lack of electrolytes’ thing has been debunked. It seems to be something about the muscle getting inhibited in its ability to stop the contraction. Maybe sleep does something similar to fatigue. Another thing that seems to promote cramping is contracting a muscle in the shortened range.

      Reminds me – you might like the book sold by Alex at sweatscience.com. It’s like the greatest hits of Lore of Running in a very short readable format (with a good section on cramping.)

  13. Barbara says:

    Very well written!! I struggle with the words to explain this to my massage clients. Some want me to dig deeper, or as I call it “a bigger hammer”. I’m currently learning Ortho Bionomy which uses the CNS to help facilitate a release of the muscle by putting it in it’s most comfortable position. Fascinating!!! (it’s early and my spelling could be way off). Thanks. Barb

  14. Brad says:

    Great article again Todd ! Did you heard about the method of Guy Voyer o french osteopath ? It is called LOADS :
    “Longitudinal Osteoarticular Decoaptation Stretches (LOADS) are postural self-normalizing techniques which aim at widening the space within a chosen articulation. For example, it is possible in one minute a day to relieve disc compression between T6-T7 or even more specifically at the base of the long arm of the left sacroiliac joint. It is possible to create more room in a particular articulation with an exact position adapted to each person.”
    I quote the desciption by the author without guaranty if the method keeps it promises.
    Basically it is some fascial stretching and spine lenghtening inspired by Meziere and active postural stretching (methods well know in the Physiotherapy school of France and Belgium.).
    Quite an evolution in regards of classic stretching, but still not sure it is not also deforming the structure by creating a forced spine extension. You can have an example of this method here :
    http://www.chirofind.com/mpacms/dc/article.php?id=31998&MERCURYSID=5e70271c..
    Or searching eldoa (loads in english) on youtube.

  15. Mike says:

    “That calms the nerves of white people”. Oddest sentence I’ve read in a while when describing eastern spiritualism. Do white people have different ham strings?

  16. John says:

    Great article. However, I don’t think any of the other comments brought it up and i don’t see it mentioned in the article: what’s your opinion on stretching muscles that are not necessarily tight/stiff sore, but simply sore from physical activity? Does your central nervous system use the pain of a sore muscle from lifting weights as the same kind of warning as the pain from a muscle that is stiff or tight?

  17. Cheer’s for another great post. I love how you make them think. I work in China atm, and man i want shot people sometime’s, maybe that bullet will relax their hamstring actually? well at least give the brain something else to be more concerned about.

    Their athletes are in pain, so what do they want, their ‘experts’ say, must massage harder. The more pain, no problems send them to that big guy he can massage ‘harder’. Stretching, do u feel pain? no, ok now? no, ok now? yes – ok that’s a good stretch.

    I think my name said it (frustrated). I love your reasoning and i like the way you put it simply for the public masses too. And we do see with hamstring, how after some lumbo-pelvic stability exercises or even some mobilizations on the back or SIJ, and it’s relaxed. And the patient is like WOW that physio is magical. But no as you said it isn’t always tight, simply because of a length issue, there are so many other factor causing that tightness. And we do need to think about this and address this.
    Cheers
    Shane.

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