Stretching is over-rated, which I explain in another article, Quite a Stretch. But in a nutshell: it doesn’t reduce injury rates (there are better ways), it doesn’t stop soreness after exercise (nothing does), and it isn’t a good “warm up” (there are much better ways to warm up, especially mobilizing). Not only is stretching much less effective at increasing flexibility than people think (it’s actually difficult and fairly dangerous), flexibility itself is also over-rated (being “inflexible” isn’t a problem for most people) and difficult (I never get more flexible, and God knows I’ve tried). Although stretching does feel good, and it can often take the edge off of muscle pain and stiffness … it rarely works any miracles or cures for muscle “knots.” Alas.
Considerable scientific controversy and mystery surrounds some of these points, but there are just too many reasonable doubts to ignore: the science of stretching tends to underwhelm anyone who looks into it. But then there’s also a significant mechanical difficulty…
It’s all about the anatomy. Anatomy is quite variable — for some wacky examples of anatomical variation see You Might Just Be Weird — but it works the same for most people.
The most under-reported problem with stretching is the limits of straightforward biomechanics: many large muscles are physically impossible to apply much tension to. They are just anatomically arranged in a way that makes stretching them awkward, to the point where you can’t apply tension on them to a pleasing degree. This concept is so simple that there can really be no controversy, no debate. To observe it is to know it. And once it’s pointed out, you can’t go back — it will be forever obvious that a lot of important muscles simply can’t be effectively stretched. I call them “the unstretchables.”
Perhaps the most “stretchable” muscle group in the body is the hamstrings group on the back of the thigh: the biceps femoris, and the entertainingly named “semis,” semitendinosus and semimembranosus.
We are nicely built for hamstring stretching. Thanks to the arrangement of our parts, there is almost no limit to the amount of tensile force we can apply to the hamstrings — much more than the muscles can actually tolerate. If you could stand the pain, you could easily tear your hamstring muscles. You could literally rip them apart. Wow.
There are a few other muscles like this in the body.
But precisely the opposite is true of several other muscle groups in the body. Just as anatomy happens to facilitate strong tension on the hamstrings with convenient and powerful leverage — applicable simply by leaning forward — many muscles just happen to not allow full elongation and/or conveniently applicable and powerful leverage. There are several muscles that you cannot even stretch, let alone tear, not matter how hard you try.Thanks to the arrangement of our parts, there is almost no limit to the amount of tensile force we can apply to the hamstrings — much more than they can actually take.
The most straightforward example of an un-stretchable muscle is the thick shin muscle. Yes, your shin has a muscle — the tibialis anterior (the meat in the meaty part of the shin).
The tibialis anterior muscle lifts the foot. It is elongated by pointing the toe like a ballerina, technically called “plantarflexion” of the talocrural (ankle) joint. However, the ankle joint only goes so far in that direction — its range of motion is strictly limited by the shape and arrangement of the ankle bones. There’s minimal variation in this limit from person to person — even a Cirque du Soleil contortionist can only plantarflex so much.
Short of breaking your ankle, there is just no way to plantarflex enough to stretch your tibialis anterior. At maximum plantarflexion, the tibialis anterior muscle is not really “stretched” — it is mildly elongated. It is certainly longer than it is when it is contracted, but it is not being subjected to strong tensile force. It cannot be satisfyingly stretched!
And what a damned shame, too, because the tibialis anterior muscle could probably use a good stretching. It is often stiff and painful, because it harbours one of the body’s classic trigger points — perfect spot for massage #3! — and it’s clinically significant in nearly every case of shin splints (regardless of which type of shin splints) and plantar fasciitis, two of the most common and annoying musculoskeletal problems in the world.
Tough luck. You can’t stretch your tibialis anterior. It’s biomechanical destiny.
There are about 300 skeletal muscles in the human body. Sort of. It depends on how you count them. See How Many Muscles? A (slightly tongue-in-cheek) tally of the body’s many muscles.
Many of them are unstretchable, but many of those don’t really matter much. Consider the humble coracobrachialis muscle — from a massage therapist’s perspective, it’s about as clinically ho hum as they come: a minor helper in shoulder flexion, overshadowed and overpowered by the famous biceps and the obscure but powerful brachialis muscles, the coracobrachialis is almost never clinically significant. Rarely injured in isolation, never even home to a terribly troublemaking trigger point, the coracobrachialis is not just unstretchable … no one even cares to even try.
The Unstretchables — with a capital ‘U’ — are the ten muscles in the body that we can’t stretch to a satisfying degree but wish we could.
|Why they can’t be stretched||Why it’s a dang shame|
|masseter and temporalis||The jaw can only open so far.||Jaw tension is epidemic, and trigger points in these muscles cause a wide array of strange face and head pains, including toothaches, headaches, and earaches.|
|the suboccipitals||Neck flexion is stopped by the chin hitting the chest, sharply limiting suboccipital stretch in most people. Although mildly stretchable in some people, it’s impossible for others, and an awkward and limited stretch for most.||Trigger points in this muscle group are the primary cause of tension headaches.|
|supraspinatus||This muscle lifts the arm to the side. Going the other way is impossible: the torso is in the way!||Supraspinatus, like all the infamous rotator cuff muscles, is prone to trigger point formation and injury. It’s also the site of common shoulder problems (supraspinatus tendinitis and/or supraspinatus impingement syndrome).|
|pectoralis minor||Can only be stretched by lifting the scapula, which is limited by many other tissues and lack of leverage — there’s just no way to apply the stretch. Standard pectoralis stretches primarily effect the pectoralis major.||Routinely a cause of significant feelings of tightness and pain in the chest and arm, and it may also be a factor in thoracic outlet syndrome, which includes impinging the brachial artery and impairing circulation to the arm.|
|thoracic paraspinals||The thoracic spine is naturally flexed (thoracic kyphosis) and can’t flex much further due to the presence of ribs and sternum in front — i.e., you can only “hunch” your back and collapse your chest so far.||The big spine muscles in the upper back may be the single most common location in the entire body for minor but exasperating muscular tension and aching.|
|supinator||This muscle rotates the forearm to turn the palm upward (supinating). Turning the other way (pronating) to stretch, the radius simply collides with the ulna.||Although an obscure muscle, the supinator is nevertheless a key player in lots of wrist pain (often including carpal tunnel syndrome), tennis elbow, and golfer’s elbow.|
|latissimus dorsi||Too long and lanky to stretch — no matter how far you move the arm, tension on the latissimus dorsi remains fairly low.||With its broad attachments in the low back, it would be nice to be able to try stretching this muscle strongly as a part of low back pain self-treatment.|
|the gluteals||Stretching of the surprisingly long gluteus maximus muscle is blocked by the limits on hip flexion: the belly hits the thigh long before the muscle is truly stretched (especially if you’re overweight). The smaller gluteus medius and minimus, which lift the leg out to the side, can be stretched only awkwardly at best — the other leg gets in the way!||All of the gluteals commonly contain trigger points that are clinically significant in most cases of low back pain, hip pain, sciatica, and leg pain. It would be wonderful to have the option of stretching them!|
|the quadriceps (seriously)||The most surprising of the unstretchables, because everyone has done a quadriceps stretch, and you probably think you “know” that they can be stretched. However, you were only stretching the rectus femoris muscle — about 10–15% of the mass of the group. It feels like a strong stretch, and it is — of that tissue. But the other 85–90% remains only mildly elongated. The quadriceps consists of four muscles: the skinny rectus femoris and the three huge “vasti” — vastus lateralis/intermedius/medialis. The vasti are only elongated by knee flexion, which is limited to about 120˚ when the calf hits the hamstrings. (See diagram below.)The vasti cannot be stretched strongly.||Even more surprising is that stretching most of the quadriceps strongly is not only impossible, but clinically unimportant. It would probably feel great to stretch them, but the state of the quadriceps is not a major factor in any common problem.|
|tibialis anterior||Limited ankle flexion.||Stretching would likely be helpful for self-treatment of shin splints and plantar fasciitis.|
|the foot arch muscle||The connective tissues in the arch of the foot are shorter than the muscles. When you stretch the arch, the first thing you feel is the plantar fascia reaching the limits of its elasticity. The arch muscles are also elongating, but not strongly.||The arch gets tired and achy easily, and being able to stretch it would probably be a great pleasure — and a great help to plantar fasciitis sufferers.|
|the IT band||Not a muscle, really. But the iliotibial band (actually sort of a giant tendon for the tiny tensor fasciae latae muscle) is one of the most stretched of all anatomical structures … and the most uselessly so. Supposedly IT band stretching is a treatment for IT band syndrome (runner’s knee). However, there is a perfect storm of unstretchability here: not only is the IT band unbelievably tough, but it cannot even slide or elongate because it is firmly attached to the thigh and femur. Its immunity to stretch has been quite well studied (see Falvey et al).||If only you could actually stretch the IT band, perhaps it would be an effective treatment for a frustrating repetitive strain injury. This topic is analyzed in great detail in my IT band syndrome tutorial.|
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.
Inevitably, some smarty-pants kinesiologist or therapist will write to me to complain about this list, claiming that they know how to stretch those muscles, and just because I don’t know my stuff I shouldn’t be yada yada yada. (This kind of reaction seems to be par for the course with the subject of stretching, which inspires bizarre emotions and strange loyalties in people.)Inevitably, some smarty-pants kinesiologist or therapist will be writing to me to complain about this list.
So let me address that inevitable complaint about this list off right now and say, “Yes, but.” Yes, I’m sure there are miracle methods that can get a certain amount of stretch out of some of these muscles: but not much, and not easily.
If you have an urge to bitterly complain about my list, start by suppressing that impulse, and then consider the possibility that you are taking this way too seriously. 😃 To quibble over the individual muscles and stretches is to miss the point. Which is …
Not remotely. An increasingly common response to this article is to claim that the unstretchables are in fact stretchable via the rather arcane mechanism of “fascia” (sheets of connective tissue). Here are some typical examples (errors reproduced as received):
These protests all share a conviction that you can somehow stretch a muscle even when you are not able to do so by moving its primary joint. This is easy enough to test. Either you can produce significant tension in a muscle without moving its primary joints or you cannot. Can you? Try it.
I certainly can’t. Nowhere in my body can I produce any noteworthy pull on any popularly stretched muscle without moving the joint it crosses. I No significant increases in tension are ever observable without elongating the obviously involved muscles. cannot stretch my ass by extending my knee. Are the glutes and hamstrings fascially connected? Enough that I can somehow pull on my glutes just by playing with my knee position? Not even close.
Muscle stretch is consistently obvious in response to the straightforward biomechanical relationships. But absolutely no significant increases in tension are ever observable without elongating the obviously involved muscles.
Another example: the second reader comment above concerned the quadriceps specifically. It implied that the vasti have such substantial non-tendinous connections above the hip joint — not just above the vasti, but above the hip — that hip extension might actually result in a real pull on the vasti group. I don’t buy it. In fact, it’s pretty far out.
All of this speculation misses the point completely. It’s just more bizarre intellectual squirming to avoid the perfectly harmless conclusion that stretching isn’t all it’s cracked up to be. It’s also yet more unjustified aggrandization of fascia as a tissue (as if there wasn’t enough of that already). See Does Fascia Matter? A detailed critical analysis of the clinical relevance of fascia science and fascia properties.
The unstretchables are a problem for stretching. But what about the almost unstretchables?
For every more or less unstretchable muscle in the body, there are a half dozen more than are at best rather awkward to stretch. Thus, stretching as a self-treatment suffers from a major practical limitation, and can really only be used with the handful of major muscles/groups that just happen to be conveniently stretchable.
We don’t stretch what we need to stretch … we stretch what we can stretch. Which isn’t all that much. The neck and low back. The hamstrings and calves. The tiny rectus femoris part of the quadriceps. The abdominals and iliopsoas. The pectoralis major. Some of these are indeed pleasant to stretch and may have therapeutic value. But there are many important muscles left out …
If muscles cannot be stretched due to straightforward mechanical limitations, then they are simply immune to all of the rest of scientific controversy about stretching. If a lot of important muscles can’t be stretched, then there’s less value in debating the effects of stretching.
It’s just another thing that makes the stretching “debate” seem over-rated to me.We don’t stretch what we need to stretch … we stretch what we can stretch.
Er … social implications?
As noted earlier, the subject of stretching tends to get people a little bent out of shape, so to speak. I’ve never really understood why, but that’s how it is. Now that you understand the concept of “unstretchable” muscles, I have cursed you with a heavy burden of secret and unpopular knowledge, and you are on an ideological collision course with devoted fans of pointless stretches.
For instance, let’s say you’re a runner (and a great many of my readers are). From now on, you’ll never, ever be able to “stretch” your quadriceps alongside other runners without wanting to say something about it. But just try it. You’ll find out what I mean. It gets awkward and weird, fast. People do not like their stretches to be criticized.
I’m so sorry I’ve done this to you. Good luck out there.
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.