Feel stiff? Tight? Think your range of motion is uncomfortably limited? These things often go together, but they don’t always, and they definitely aren’t the same. Wrapping your head around the difference is good human body user manual stuff.

Only you can say that you’re stiff. “Stiff” and “tight” are imprecise, informal, subjective terms: they are noxious sensations that probably indicate minor pathology, a kind of mild pain. In other words, stiffness is a symptom.

It’s a common symptom, and people are forever trying to fix it. They are stretching and contorting themselves in hot yoga classes. They are trying to correct their posture. They go to chiropractors for “adjustments” and massage therapists for “release.” The most common words in massage therapy offices are “you’re really tight”… and they are mostly meaningless words. Concern about tightness is at the heart of the fascia fad.1

Symptoms have many causes, and people often place the blame for stiffness on the wrong ones. Thinking of stiffness as a form of minor pain is quite a useful perspective.

What causes stiffness?

Stiffness is an unpleasant sensation — it feels like something is wrong. No one ever feels comfortably stiff.2 So what’s wrong? If stiffness is a symptom, what’s the disease? There are many plausible causes. I’ve presented them here roughly in order of how common they are, and note that only one of these actually involves a limited range of motion.

Some of these causes are explored in more detail below.
exercise soreness
“muscle knots”
overuse injury, especially tendinopathy
arthritis, “inflammaging”
inflammation caused by infection and autoimmune disease
unexplained chronic widespread pain (e.g. fibromyalgia)
generalized anxiety disorder
medication side effects, poisoning
dystonia (muscle spasticity and rigidity), which has many possible causes — and this is the one that can definitely can involve limited ROM
I saved the weirdest for last: hypermobility can cause stiffness!
Diagnosing stiffness is at least as hard as diagnosing full-blown pain, which is often very hard indeed. It’s like trying to diagnose a “funny feeling.” It’s just as subjective as pain, but subtler.

“I feel really stiff — it’s nice!”

said no one ever
It’s rarely about range of motion

I am an extremely stiff person; I have significant troubles with chronic pain,3 and I usually feel like I cannot move nearly as well as I would like to move.

And yet I can move just fine. If I test myself, my range of motion (ROM) is perfectly normal.

People with normal ROM, or even good ROM, can feel amazingly stiff and tight. In fact, abnormal hyper-mobility is a common cause of stiffness!4 In this highly scientific Twitter poll, more than 80% of people with hypermobility disorders claimed to feel more stiff than the average person, or way more stiff:

Poll for people with hypermobility (hypermobility spectrum disorders & Ehlers–Danlos syndrome): Do you feel “stiff,” despite being hypermobile? How often, how bad?

— Paul Ingraham (@PainSci) April 12, 2018
At the other end of the spectrum, people with measurably lousy range of motion can actually feel perfectly fine, no stiffness at all.

Why such variety? Probably because stiffness, just like pain, is an extremely unpredictable sensation overprotectively imposed on us by our brains for reasons we are often oblivious to.5

There are a handful of conditions which involve truly restricted movement (more about dystonia below), but most people with those problems usually don’t talk much about “stiffness.” It would be like complaining about your house being too “warm” while it’s burning down.6

The symptom of stiffness usually occurs well within normal ROM, whether it’s large or small. You can feel stiff when you stand up from a chair — an action that isn’t even constrained by really poor flexibility.You can feel stiff when you stand up from a chair — an action that isn’t even constrained by really poor flexibility. And when you’re sore after a hard workout, you can stretch just as far as normal — but it will hurt more, and many people describe that as stiffness rather than sore or painful.

But stiffness is a misleading symptom, and most people who feel tight assume that they are literally tight, that they have a measurably limited ROM. Few are correct. Some people do have abnormally restricted ROM, but it’s surprisingly rare, and still doesn’t necessarily have anything to do with feeling tight. A short but healthy range of motion is probably never in itself the cause of any wrong-feeling stiffness.

If your ROM is limited by natural biological variation, pushing at the end of the range is a neutral sensation — it doesn’t feel like there’s a problem, and therefore it is not “stiff.” It’s more just a sensation of being stopped, or of pulling too hard.

“Normal” range of motion is almost meaningless

Range of motion is the only clear objective measure of flexibility. You can measure it with a protractor.7 Limited ROM can be confirmed in joints that actually cannot move as far as they “should” be able to move.

Which is how far, exactly? Human averages are almost meaningless, because the range of natural variation is quite large.8 A better measurement might be how much you want or need a joint to move — for instance, gymnasts need ROM more than accountants do. However, a desired or perceived need for ROM is not a good standard either, because so many people assume that their range is worse or more “abnormal” than it actually is, and because they assume that more range is better than it is.

Abnormal is normal. There is an extraordinary amount of non-pathological anatomical variation in humans. There are many interesting examples.9

Being flexible ain’t all it’s cracked up to be

Doing the splits is not exactly a useful skill. Flexibility (and stretching as a fix) is generally over-rated. Many people have much less natural ROM than many others, especially men in their hamstrings. This doesn’t hold them back in any way other than being unable to touch their toes, but men routinely bemoan their lack of flexibility.

The martial arts seem to demand flexibility, and of course it can be a powerful asset, but even here it’s not necessarily so. The most memorable martial artist I ever worked with — a formidable, grizzled old practitioner of Aikido — was also one of the least flexible.10 For much more on the myth of the value of flexibility, see Quite a Stretch.


Subjective sensations of stiffness are amazingly unrelated to objective measures of flexibility. Stiff people can be flexible & inflexible people can feel no stiffness.
The most obvious causes of acute stiffness

There are some instructively familiar circumstances where we get stiff: the early stages of cold or flu, and the soreness that follows a relatively big bout of exercise (delayed onset muscle soreness), or the complaints of joints and tendons that have succumbed to overuse injuries like patellofemoral syndrome or plantar fasciitis.

Infections clearly involve inflammation and immune system activity, and many infections cause stiffness. A couple of less common examples are probably mononucleosis and Legionnaire’s disease.

It’s a lot less clear that what’s going on with exercise soreness, but it definitely involves some kind of tissue distress.11

All of these problems usually involve actual pain as well as stiffness. We can infer from this that some stiffness must have something to do with mild tissue irritation.

But lots of people are stiff without an obvious cause like this. So what else could be going on? There are much subtler causes of stiffness.

The stiffness of aging: “inflammaging” and arthritis

How could we have tissue irritation without an obvious source? Chronic mild to moderate tissue inflammation has many possible causes, and is probably more prevalent and persistent than most professionals realize.12 But by far the most familiar source of inflammation — and stiffness — is probably just aging. Everyone gets more inflamed as they age. This is known as “inflammaging” — I’m not making this up — and it happens to some people sooner and worse than others,13 like arthritis (which may itself just be one of the consequences of the inflammation). It’s basically just a mild version of what is much more obvious and dramatic with the inflammatory arthritides (super-arthritis caused by immune system malfunction).14

And so this probably accounts for the lion’s share of musculoskeletal stiffness in anyone past their second or third decade of life.

But then there are also many young people who feel stiff. What could be going on with them? There’s still many possibilities, but muscle knots are one of the most likely.

Muscle knots (myofascial trigger points)


People seek out massage for sensations of stiffness more than pain—and they crave focused pressure on specific sore spots of unclear nature known as ‘tps’.
Some tissues probably create stronger sensations of stiffness when irritated, and muscle is a prime candidate. But why would muscle get irritated, other than a big workout? For younger people who feel stiff (and can’t just blame “inflammaging”) there is one major suspect: the ubiquitous phenomenon of “muscle knots,” technically called trigger points.

It’s unknown whether trigger points involve literal muscular tightness. They may, because the dominant theory is that trigger points are micro cramps. On the other hand, that theory is old and controversial,15 and trigger points could be pure neurology and sensation.16 So trigger-pointy tissues may actually resist stretch, or their extensibility may be unaffected,17 but they will feel stiff either way.

Regardless of how they work, these patches of soft-tissue are sensitive to pressure for no apparent reason, are extremely common, and the pain is the tip of a bio-berg: for every spot that actually hurts (an “active” trigger point), there’s usually more that are just mildly uncomfortable (“latent”). There is usually a diffuse halo of stiffness and tightness around either type of trigger point.

Dystonia-powered stiffness

This article is mostly about common musculoskeletal stiffness, not stiffness caused by disease… but there’s a grey zone between those extremes. Some pathologies involve actual range-limiting muscular rigidity and spasticity — dystonia [WebMD] — which puts garden variety stiffness into an interesting perspective.

Myotonia This interesting sub-type of dystonia involves delayed relaxation after contraction. In other words, you can contract normally … but you can only un-contract slowly. Although this is real and serious problem for some people, fortunately it’s a symptom of only a handful of rare diseases.
Dystonia is a lot of things. Along with tremors, it’s one of two broad categories of unwanted contractions. Many sub-types of dystonia don’t resemble ordinary muscle and joint stiffness at all. Major examples:

Torticollis (wry neck) is the most classic example of a common dystonia that no one is going to mistake for common stiffness, because it involves a clearly abnormal neck posture.
Parkinson’s disease, Huntington’s disease, and multiple sclerosis all cause dystonia, and all of them are distinctive as they develop.
Brain injuries, tumors, and infections can all cause dystonia.
Both meningitis and polio are notorious for causing neck dystonia specifically.
But some milder dystonias blend right in with other common aches and pains. Examples …

People with impinged or irritated spinal cords can get dystonia, which may feel just like simple stiffness, not obviously different from what you might feel the day after a workout — except that you didn’t exercise. Although these problems sound dramatic, they can be surprisingly subtle and are under-diagnosed.
Moderate dystonia is common in withdrawal from some tranquilizers, and may drag on for months or even years.18
Dystonia is often subtle during the long, early stages of some diseases: a full-blown case of Parkinson’s may be distinctive, but some patients suffer from tight muscles for a long time (years) before the disease develops enough to be diagnosed.
Facioscapulohumeral muscular dystrophy is a common form of muscular dystrophy. Milder cases can fly under the diagnostic radar indefinitely, but cause many miscellaneous musculoskeletal symptoms, including stiffness and dystonia.19
So, how can you tell if you have dystonia, as opposed to just a sensation of stiffness? It’s not easy, and it might not be possible. But dystonia-powered stiffness usually involves genuine limitation of range of motion and, often, signs and symptoms of some other pathology, which usually become more prominent as time goes on.

Stiff-person syndrome? For real

Believe it or not, there is a (very rare) disease specifically defined by stiffness called stiff-person syndrome. It is a rare neurological disorder, probably autoimmune in nature, causing rigidity in the trunk and limbs, an abnormally hunched posture and spasms that are set off by stressful and startling stimuli (a severe case of dystonia with a specific, rare cause). This has nothing at all to do with ordinary musculoskeletal stiffness, of course — it’s just bizarre and fascinating nightmare fuel for hypochondriacs!

Contracture: the ultimate stiffness

Contracture is a permanent shortening or shrinkage of tissue. Many people will never experience any significant contracture, as it is mostly associated with pathological spasticity — clenching so serious and unrelenting that you literally get “stuck like that.”

Frozen shoulder is one of the only common musculoskeletal problems caused by a true contracture.20 People with frozen shoulder are truly mechanically stiff, obviously. (And yet, there is also evidence that at least some cases of frozen shoulder are in fact a form of spatisticty, a clenching shoulder.21)

There are a few related conditions that cause contracture of different body parts, most notably Dupuytren’s Contracture, a contracture of the fascia of the hand. The others are much more obscure.

Again: there is nothing like contracture going on in most people. Contrary to popular belief, healthy anatomy never suffers in any important way from connective tissue “adhesions” or “scar tissue.” These are the pseudoscientific delusions of an industry that profits by selling “release” — an easy pitch to people who feel restricted.

Fibromyalgia

Fibromyalgia is a common, unexplained, and mostly untreatable illness of chronic pain, fatigue, and mental fog affecting about 1 in a 100 people. Its non-specific symptoms are often confused with (and/or related too) many other conditions. Controversy, stigma, quackery, and junky science swirl around fibromyalgia like a bad smell. Only a handful of imperfect treatment options exist, most notably exercise and scrupulous sleep hygiene. See A Rational Guide to Fibromyalgia: The science of the mysterious disease of pain, exhaustion, and mental fog.

People with fibromyalgia also tend to feel stiff. Diffuse pain is nearly synonymous with stiffness.

Given that fibromyalgia is unexplained (by definition), it is possible that some cases involve limited mobility and/or muscular tightness. But it’s more likely that the sensation of being a little sore all over is just indistinguishable from uncomfortable movement.

Psychogenic stiffness

Anxiety disorder is actually a well-known cause of dystonia. We “tense up” when we are anxious and if that emotional state is severe and persistent it becomes a disorder and the dystonia gets entrenched.

But I think psychogenic stiffness can be even more subtle. Maybe if you feel emotionally stuck your mind has some ways of feeling that way in the flesh as well. Some stiffness may be a form of self-expression, a common embodiment of many flavours of discontent. The transference from a state of mind to a state of body is somatization, and we’re not as far out in left field here as it sounds like. Psychosomatic illness is probably more common and more serious than we realize, and milder forms therefore are also likely ubiquitous.22 We already know that mood, posture and even pain sensitivity can probably modify each other — the “power pose” thing.23 It’s really not much of a leap that believing you are stiff could result in feeling that way — even without frank dystonia.

Body is not stiff, mind is stiff.

~ K. Pattabhi Jois

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About Paul Ingraham

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.

Related Reading

For more information about trigger points, see my ebook The Complete Guide to Trigger Points & Myofascial Pain or free articles like my popular Perfect Spots series. For more about why stretching is over-rated, and why most people stretch for the wrong reasons, see Quite a Stretch — which is always good for starting an argument.

Some other related articles …

Cramps, Spasms, Tremors & Twitches — The biology and treatment of unwanted muscle contractions
You’re Really Tight — The three most common words in massage therapy are pointless
Does Massage Therapy Work? — A review of the science of massage therapy … such as it is
Thixotropy is Nifty, but It’s Not Therapy — A curious property of connective tissue is often claimed as a therapy
Does Fascia Matter? — A detailed critical analysis of the clinical relevance of fascia science and fascia properties
The Unstretchables — Eleven muscles you can’t actually stretch hard (but wish you could)
What’s new in this article?

Eight updates have been logged for this article since publication (2007). All PainScience.com updates are logged to show a long term commitment to quality, accuracy, and currency. more


May 13, 2020 — Comprehensive editing with many improvements and clarifications.

2018 — Added results of a poll on how stiff people with hypermobility syndromes feel. Noted an exception to the rule that stiffness is uncomfortable. Added a brief, broad explanation of why stiffness correlates so poorly with ROM. Elaborated on examples of pathological causes of dystonia and put them in lists. Added a new example, facioscapulohumeral muscular dystrophy. Many other minor additions and edits for clarity.

2018 — Miscellaneous additions and improvements about inflammatory diseases, myotonia, dystonia induced by tranquilizer withdrawal, contracture, and frozen shoulder.

2018 — New section about dystonia-powered stiffness, plus numerous other clarifications and improvements.

2018 — Still more revision and re-organizing, with a number of helpful elaborations.

2018 — Thorough editing, numerous clarifications, some pruning and re-organizing. The article now focusses much more strongly on causes of the symptom of stiffness.

2016 — Several miscellaneous improvements, especially new information about the role of inflammation and “inflammaging.”

2016 — Minor update. Added a neat footnote and citation about the trouble with “average” ranges of motion. Plus miscellaneous editing.

2007 — Publication.

Notes

Fascia is sheet-like connective tissue, the “gristle” that wraps around everything at every scale in the human body. In the early 90s, physician Stephen Typaldos formulated the Fascial Distortion Model (FDM), proposing that most musculoskeletal complaints are caused by fascial deformations and restrictions. He thought they could be fixed by skilful force, kind of like banging the dents out of a car. That idea was the seed for a huge fad that is now a roaring bonfire of hype. For more information, see Does Fascia Matter? A detailed critical analysis of the clinical relevance of fascia science and fascia properties.
As a colleague of mine pointed out, there is at least one notable exception to that rule. 🙄

As another pointed out, stiffness can feel satisfying after a good workout — it’s a kind of validation, proof of your effort. I’m not sure that psychological contentment and a lack of concern actually make it “comfortable,” but I guess I wouldn’t really call it a symptom either. However, for many people, if not most, post-exercise stiffness is not a pleasant or sastisfying sensation: it’s something annoying and unpleasant they wish they could treat (and they certainly try, in all kinds of ways).

I had always been “prone” to aches and pains, which is really why I started this website. But in 2015 I graduated to the pain big leagues: serious chronic pain, fatigue, and exercise intolerance plus many other bizarre symptoms, all unexplained, making me a classic fibromyalgia patient. You can read my chronic pain story on my personal blog: “Chronic Pain & Tragic Irony.”
Hypermobile patients get hurt easily — especially repetitive strain injuries — and have a lot of chronic body body pain. For instance, hypermobility is “highly prevalent among patients diagnosed with chronic pain” (Scheper).
Modern pain science shows that pain is a volatile, complex sensation that is completely tuned by the brain for primarily protective reasons, and often over-protective, so much so that sensitization often becomes more serious than the original problem, a state of chronic false alarms, AKA chronic pain. See Pain is Weird.
The concept of stiffness is too trivializing for these patients to focus on it. They are understandably more concerned with the loss of function than how it feels. A couple examples:

Someone reporting Dupuytren’s contracture symptoms to their doctor would probably choose to say, “I can’t open my hand fully,” not “My hand feels stiff.”

Or someone with spasticity from multiple sclerosis would probably not say, “I’ve been feeling awful stiff lately, doc.” They would speak of significantly impaired function. They might use the words stiffness or tightness, but only as a reference point: “My ribs feel so tight it’s like I’m being strangled.”

Actually, a “goniometer” — a more advanced sort of protractor used for measuring limb angles in kinesiology (and much else).
Ironically, almost no one is average, if you take more than a couple measurements of them. For instance, the American Air Force had a crisis of excessive crashing in the 1950s because they’d built their cockpits for “average” pilots, but most pilots didn’t fit in one or two crucial ways, and couldn’t control their planes because of it: “When he looked at just three [measurements], less than five percent [of the pilots] were average. Daniels realized that by designing something for an average pilot, it was literally designed to fit nobody.” That’s from a fascinating article/podcast episode on this topic: see On Average (Episode 266 of 99% Invisible).
Strange, wonderful, and problematic anatomical variations occur in humans all the time. Over the years, I’ve collected several interesting examples relevant to musculoskeletal medicine. For more information, see You Might Just Be Weird: The clinical significance of normal — and not so normal — anatomical variations.
He seemed flexible, but it was all in how he used what little range of motion he had. He worked within his limitations like an artist — a martial artist! — and you probably would never even guess that he had quite limited ROM unless you spent time with him in training, and watched him failing to touch his toes.

His wrist ROM was especially memorable: it was like his hands were welded onto the end of his forearms. He once showed me how far he could bend his wrist back, which was not at all. Aikido uses a lot of wrist locks, so his sturdy and inflexible wrists made him almost impervious to those … but with no detectable functional deficit either.

The traditional notion of “microtrauma” is probably wrong, or at least only half the story. The most promising modern theory is that the discomfort is caused by “neurological growing pains,” as nerves literally grow in response to exercise. For more about this, see Post-Exercise, Delayed-Onset Muscle Soreness.
To start with just one example: Research has shown that immune cells (neutrophils) unnecessarily “swarm” sterile injury sites, causing damage and pain with no known or likely benefit as a tradeoff. It’s just a clear error: they appear to have mistaken mitochondria for a foreign organism, a legacy of ancient evolutionary history, and a biological glitch with profound implications about why some painful problems are so severe and stubborn. See Why Does Pain Hurt? How an evolutionary wrong turn led to a biological glitch that condemned the animal kingdom — you included — to much louder, longer pain.
Ingraham. Chronic, Subtle, Systemic Inflammation: One possible sneaky cause of puzzling chronic pain.  ❐ PainScience.com. 7109 words. Chronic, subtle, systemic inflammation may be a factor in stubborn musculoskeletal pain and arthritis. We get more inflamed as we age, a process quaintly known as “inflammaging,” which correlates with poor fitness and obesity (metabolic syndrome, the biological precursor to diabetes and heart disease). And that, in turn is linked to chronic psychological stress, and of course biological stresses like smoking and sleep deprivation. And then there are several other unproven but plausible reasons why inflammation escalates as we age, such as the accumulation of permanent minor infections, lasting collateral damage from past infections (essentially autoimmune disease and allergies that are too subtle or nonspecific to diagnose), and environmental poisons. Unfortunately, systemic inflammation cannot be diagnosed or treated reliably by any means: it is simply too complicated and mysterious. Nevertheless, it is a trendy bogeyman. Probably the best defense is simply to be as fit and healthy as possible.
Basically all of autoimmune diseases causes stiffness. One of the most dramatic is polymyalgia rheumatica, a weird one I have personal experience with: my father was attacked by it in the early 2000s, and woke one day up barely able to move his arms and shoulders. This disabling condition was quickly and well-controlled by a drug, and slowly faded away over the next year.
FMperplex.com [Internet]. Wolfe F. Travell, Simons and Cargo Cult Science; 2013 Feb 19 [cited 17 Oct 27].
An informal survey of the poor state of trigger point science from an articulate expert, Fred Wolfe, a rheumatologist. Dr. Wolfe gives his first-hand account of the first trigger point diagnosis reliability study in 1992 (see Wolfe), and he tells the story of meeting Dr. Janet Travell and observing her unscientific conduct with a patient.

Quintner JL, Cohen ML. Referred pain of peripheral nerve origin: an alternative to the “myofascial pain” construct. Clin J Pain. 1994 Sep;10(3):243–51. PubMed #7833584 ❐ PainSci #54775 ❐
Quintner and Cohen’s 1994 paper is a historically significant critique of the “traditional” (Travell & Simons) explanation for the phenomenon of trigger points, known today as the “integrated hypothesis.” They propose that peripheral nerve pain is a better explanation. More specifically, they proposed that irritated or injured peripheral nerve trunks may be the cause of pain, rather than lesions in muscle tissue. This hypothesis has advantages and problems, just like the idea it is intended to replace. Its main problem is that there’s no obvious plausible mechanism for ubiquitous nerve irritation. I review the hypothesis more thoroughly in my book, The Complete Guide to Trigger Points & Myofascial Pain.

An updated version of this paper was published in 2015 in Rheumatology (Oxford).

It depends on several variables, like the muscle mass and length and the number and severity of the trigger points. Also, the mechanism of stretch-resistance is unknown: it could be physical tissue stiffness (the nervous system is willing, but simply cannot overcome physical resistance in the tissue), or inhibition and resistance (the brain refuses to allow the stretch, because it’s too threatening). That’s a sloppy thumbnail sketch, just for glimpse at how complicated it all is.
Benzodiazapenes (Valium, Ativan, etc) are muscle relaxants and anti-convulsants (among other things). Benzodiazepene withdrawal is notoriously difficult. Even when done slowly and carefully, these symptoms are often exacerbated rather than suppressed. It’s much worse when people unwittingly try to get off the drugs too fast, or they have many skirmishes with unintended withdrawal (due to erratic dosing), and/or they have long term consequences of withdrawal (an unexplained phenomenon that affects some people).

Benzos boost the effect of GABA, a neurotransmitter, which is one of the body’s built-in sedatives. Basically, GABA makes neurons less sensitive, less sparky, less easily fired. This is why benzos are “downers.” But many other tissues produce and respond to GABA! GABA also suppresses muscle tone, which has consequences when the GABA pendulum swings the other way. And so the effect of benzos is widespread and often involves dystonia.

I have two good, old friends, brothers, who have this condition. One of them has been suffering acutely since his early 40s, the other has yet to have any serious symptoms but has pronounced atrophy of his trapezius muscle and a litany of classic minor FSHD symptoms. Both brothers recall minor symptoms they had for 10-20 years before diagnosis that were obviously due to FSHD. Their father, now passed away, had classic but minor FSHD symptoms for his whole life, especially an inability to do manual work above his head — but he was a stoic, never sought a diagnosis, and likely wouldn’t have gotten one even he had. Fascinating.
Nagy MT, Macfarlane RJ, Khan Y, Waseem M. The frozen shoulder: myths and realities. Open Orthop J. 2013;7:352–5. PubMed #24082974 ❐ PainSci #53682 ❐
Although its medical name, adhesive capsulitis, implies that it’s disease of “stickyness” of the joint capsule, the best evidence suggests that it’s more a disease of shrinkage — connective tissue contracture. The nature of frozen shoulder is addressed in detail in my full frozen shoulder tutorial.

Hollmann L, Halaki M, Haber M, et al. Determining the contribution of active stiffness to reduced range of motion in frozen shoulder. Physiotherapy. 2015 2018/06/19;101:e585. PainSci #53197 ❐ Five capsular release surgery patients had their passive range of motion checked before and after being put under general anaesthesia. All five of them had “significantly more passive shoulder abduction” when they were knocked out … which would be impossible if their shoulder joint capsules were actually contractured or adhered or full of cement or had any physical limitation. The improvement in ROM ranged from a minimum of 44˚ all the way up to a 110˚ boost (all the way back to normal).
O’Sullivan S. It’s All in Your Head: True Stories of Imaginary Illness. Chatto & Windus; 2015.
This book consists mainly of well-told stories of severe psychosomatic illness and functional neurological disorders (neurological symptoms without diagnosable disease). The key take-away is that psychologically powered illness is common and can be amazingly severe. Although Dr. O’Sullivan is clearly concerned about the risk of incorrect diagnosis, and she is cautious and compassionate enough that I think she mostly gets it right (with the notable exception of the chronic fatigue chapter). It’s well-written and fascinating and has plenty to offer. I do wish there were citations.

Power posing is an infamously notoriously over-hyped idea (see Carney), based on research that seemed to show that striking a “powerful” pose makes people feel and act more powerfully, complete with hormonal changes. That was questioned by many. But follow-up research has been solid enough that I feel comfortable concluding that a confident posture can influence our emotions at least a little. See Carney et al for much more information.