There is a lot of anecdotal evidence that stretching relieves those sensitive, stiff, aching spots in muscle that torment humanity: trigger points. The ancedotal evidence is massive, an avalanche of faith. People with aches and pains swear by stretching. It’s practically religion. It’s one of the most common of all self-treating behaviours.
Other than all that confidence, is there any reason to think it actually does anything? In the near perfect absence of direct scientific evidence? What’s the science of stretching muscle “knots”?
Expert support for stretching trigger points
In the weighty text Muscle Pain (2000), expert authors and researchers Dr. David Simons and Dr. Siegfried Mense are enthusiastic about stretching as a treatment for trigger points. Stretching is mostly quite disappointing as a therapy for other problems. See Quite a Stretch. If stretching actually helps muscle pain, it could be one of the only good reasons to stretch other than pleasure.
Unfortunately, it’s a pretty a big “if.” Trigger points are also controversial and mysterious, and it’s not clear that stretching will help them even if trigger points actually work the way Simons and Mense believe they do.
They propose that “essentially any technique that elongates the muscle out to its full stretch length” constitutes effective treatment for trigger points therein. “A newly activated, single-muscle myofascial trigger point is usually remarkably responsive to simple stretch therapy,” they write. Stretching “by almost any means is beneficial … At least five ways can be used to augment simple muscle stretch.”
They make stretching for trigger points sound good. But let’s dig deeper.
Winning a tug-of-war: how stretching might help trigger points in principle
Assuming that trigger points exist as described by Simons and Mense, and if stretching ever actually works, it probably works about the same way that stretching out a calf cramp works: you win the tug-of-war with spasming muscle. It just happens on a smaller scale. This is superficially plausible. (Certainly stretching is the only defense against big cramps.)
To understand the how of it, you need to understand the controversial “exhausted contraction knot” theory of what a trigger point is: a sick, poisoned patch of spasming muscle experiencing a metabolic bad day. It is consuming lots of fuel and excreting lots of junk molecules at exactly the same time that it is choking off its own blood supply. Waste accumulates and irritates nerve endings (causes nociception), and everything goes downhill. The main idea is that it’s a vicious cycle (“energy crisis”). Therefore …
If the muscle fibres in a trigger point could be fully elongated by stretching the muscle, they cannot burn fuel. Muscle fibres can burn fuel only when the working molecules inside the muscle fibre are mostly overlapping. When stretched out and disengaged, they cannot work, like a hamster without a wheel to run in. According to Simons and Mense, the stretch-state disengages muscle fibres, interrupts contraction, and presumably allows the energy crisis to abate, the vicious cycle derailed a little more with each passing moment of stretch.
The proteins in a muscle overlap like the tines of two forks as the muscle contracts. If they are pulled apart, they can’t burn fuel.
This is state-of-the-art of trigger point science, such as it is. It is one of the most educated guesses available, from credible authors on the topic. This is about as close as we’re going to get to a good rationale for why stretching might help trigger points.
Alas, there are major concerns.
The bad news about stretching for trigger points
Even if all of the above is correct — which is granting quite a bit — there are still many problems.
There are practical circumstances in which you cannot realistically hope to win a tug-of-war with your trigger points, even if it works in principle. But there are also reasons to doubt that it even works in principle, even in ideal circumstances. If it does, it probably mostly only works on the milder cases that don’t matter very much in the first place.
The worst are infamously stubborn, and never seem to yield to mere stretch.
The idea is that you have to elongate them enough to substantially disengage the overlapping proteins that are burning fuel. A trigger point must be fully elongated in order — theoretically — to have any effect on a severe energy crisis. Many factors make “fully” elongating a trigger point unlikely.
The first is pain. After asserting that you must “fully elongate” trigger points to treat them, Simons and Mense also wisely caution that the stretch must be applied “slowly and only to the onset of discomfort.” I agree. Unfortunately, now we have a contradiction, because you can’t “fully” stretch a severe trigger point “only to the onset of discomfort.” Many people have such acute muscle pain that they couldn’t fully elongate a Slinky without going beyond the onset of discomfort.
The second big problem is just biomechanics. In many muscles, a strong stretch is biomechanically awkward at best, or just impossible (see The Unstretchables). For instance, the suboccipital muscles under the back of the head can only be stretched moderately because we can only bend our heads forward so far. This kind of thing is true of several muscles we’d certainly like to stretch more if we could.
That’s a macroscopic biomechnical problem with arranging limbs and pulling on entire muscles. There’s also a microscopic biomechanical problem in principle: trying to stretch out a trigger point is like trying to stretch out a knot in a bungie cord.
Like a knot in a bungie cord
Terms like “tight” and “stiff” are imprecise and do not clearly describe anything other than a sensation. But people with trigger points sure do feel tight and stiff and are forever trying to stretch it out. Patches of contracted sarcomeres seem to be an obvious and quite literal cause for that sensation. If we run with the mini-cramp theory, it has an obvious implication: a trigger point must actually reduce the elasticity of a muscle, like a knot in a bungie cord.
Killer analogy, right? If I stopped there, it seems like quite a compelling image that artfully connects the dominant idea of how trigger points work with an incredibly familiar human symptom. It “explains” how trigger points restrict range of motion … which in turn strongly implies the need to stretch them out. Such stories are the bread and butter of many professionals who want to put a little science sauce on their work. But if it sounds too good to be true, it probably is.
A knotted bungie cord actually still works well. Only a small segment of the cord is affected. Only at the extremes of stretch are you going to see any difference in the maximum length, and that much is probably true of knots in both muscles and bungie cords.
And good luck stretching the knot itself! The stretchiest parts yield, not the knot. Again, this is also probably true of muscle.
Indeed, the flexibility of muscles does not in fact seem to be much affected by trigger points, despite all the symptoms of stiffness and tightness, and it turns out that stretching is — although super popular — actually a surprisingly lame method of treatment that seems to have almost no consistent or lasting effect on trigger points. Probably because stretch probably can’t fix contraction knots. If indeed that’s even what a trigger point is!
Even more problems!
There’s safety to consider: stretching may or may not work, but it can definitely backfire. I almost ripped my own head off once, trying to stretch out trigger points: my worst self-treatment disaster ever. True story.
Travell and Simons — considered the world’s original experts on myofascial trigger points — were very keen on the spray-and-stretch method of treatment, which must be applied by a skilled therapist. It dominated their treatment methods. If spray-and-stretch works, it means that regular stretch doesn’t! If it doesn’t, then the Mother and Father of trigger point therapy were wrong about something critical … or they were right and it means regular stretching is mostly futile. Not a great choice.
Inefficiency is a challenge. Stretching is a slow, blunt instrument for finicky, numerous trigger points. Obscure anatomy and misleading sensations lead to wasted time and wild goose chase. This alone could account for why stretching doesn’t seem to be saving many people from trigger point pain. Even if it works, it’s just too difficult to do well.
I’ve saved the best problem for last.
What if trigger points aren’t contraction knots in the first place? The grumpy elephant in the corner here is that the energy crisis theory of trigger points could definitely be wrong… in which case good luck “interrupting” that non-existent energy crisis with a stretch.
On the other hand, if trigger points are a purely neurologica/sensory phenomenon — no “knot” — then it suggests other reasons why stretching might be helpful.
Is there any hope for stretching for trigger points?
Yes, there is some hope. Stretching feels so good that it remains plausible that there’s something to it. There could be reasons why stretching is good for pain that we don’t understand, or are only just barely starting to understand. A 2016 study (Berrueta et al) dug up some evidence that stretching reduces inflammation in connective tissues, and there is also evidence that inflamed connective tissue is involved in back pain (Langevin et al). The evidence is too scanty to trust yet, but it’s suggestive. If stretching relieves pain, it could explain why so many people think it works for trigger points.
Partial treatment of trigger points may be the main reason stretching feels so good. Many of the problems discussed above apply to the worst trigger points; the easier ones may be yielding to stretches for millions of people on a daily basis. Temporary and partial benefits are not wortheless.
There’s hope for the more difficult trigger points, too: the right conditions and variables could make all the difference. For instance, trigger points in shorter muscles may be more easily stretched. Different techniques may work, such a particularly gradual stretch, or the addition of a coolant spray like Travell and Simons advocated. We might as well experiment — if we’re cautious, the worst case scenario is that it will just feel nice.
Muscle & connective tissues are very difficult to physically change with stretch. It is probably just sensory tolerance for stretch that increases with practice.
I think the most encouraging idea is that stretching might help even if there isn’t a contraction knot. In fact, ironically, in many ways it’s more plausible than what Simons and Mense proposed.
We know that a diligent stretching habit increases flexibility, but probably not by actually changing muscle and connective tissue. Fascinatingly, it may just be our tolerance for stretch that increases with practice (Weppler et al). Muscle elongation is normally strictly limited by the brain and spinal cord, and only with repeated exposure to strong stretch can we “get used to” the discomfort and gradually push the limit back.
Trigger points might be a symptom or side effect of the nervous system imposing excessive limits on muscle extensibility. If so, they might — sometimes, when the planets align — fade away as we train ourselves with stretching to tolerate greater muscle extensibility.
Much more information about stretching for trigger points
Stretching is just one kind of self-treatment for myofascial trigger points & arguably one of the least effective. What else can you do for muscle knots?
You’ll learn much more about stretching for trigger points in the full version of the trigger points tutorial. This abridged excerpt is about 2,000 words; the complete discussion of stretching in the book is about 7,000, and it gets much more specific about many key points left out of the sections above.
There’s also much more to know about other kinds of self-treatment of trigger points. I’ve written a lot about stretching because it’s an interesting subject, and because a lot of people place a lot of their hopes on stretching. But there are probably (much) better ways to treat muscle pain. The tutorial explores them all. It’s book-length and required reading if you’re serious about tackling trigger point pain. But it now or read the first few sections for free.
About Paul Ingraham
I am a science writer, former massage therapist, and I was the assistant editor at ScienceBasedMedicine.org for several years. I have had my share of injuries and pain challenges as a runner and ultimate player. My wife and I live in downtown Vancouver, Canada. See my full bio and qualifications, or my blog, Writerly. You might run into me on Facebook or Twitter.
- PS Quite a Stretch — Stretching science has shown that this extremely popular form of exercise has almost no measurable benefits
- PS Trigger Point Doubts — Do muscle knots exist? Exploring controversies about the existence and nature of so-called “trigger points” and myofascial pain syndrome
- PS Trigger Points & Myofascial Pain Syndrome — A guide to the unfinished science of muscle pain, with reviews of every theory and self-treatment and therapy option
- PS Micro Muscles and the Dance of the Sarcomeres — A mental picture of muscle knot physiology helps to explain four familiar features of muscle pain
- PS The Unstretchables — Eleven muscles you can’t actually stretch hard (but wish you could)
What’s new in this article?
2017 — Added brief discussion of an interesting theory about the effect of stretching on inflammation in connective tissue.
2016 — Major revision. Almost a rewrite, but not quite: just a thorough re-working and modernization.