Post-Exercise, Delayed-Onset Muscle Soreness The biology & treatment of “muscle fever,” the deep muscle soreness that surges 24-48 hours after an unfamiliar workout intensity SHOW SUMMARY

Muscle fever — such a wonderfully descriptive term — is that distinctive muscle pain that nearly everyone experiences after intense or unfamiliar exercise, often peaking as long as a day or two later. Because of the delay, it is best known as D.O.M.S. for delayed-onset muscle soreness.1 Sometimes DOMS is so severe that it is mistaken for a muscle strain, an actual injury.

Muscle fever is a great term because DOMS makes your muscles feel sickly and gross as well as sore. Weakness is another symptom, major and measurable — but only hardened competitors are likely to test their strength while feeling so sore and oogy (though they probably should not). The nastiness starts after a bit of a delay, often after sleeping, and then continues for 24 to 72 hours. Some people don’t even notice it until the second day.2 If you do the same workout again a few days later, it’s nowhere near as bad.

DOMS is annoying and style-cramping, particularly if you’re starting or restarting an exercise regimen, especially strength training — which is much more worthwhile than most people realize, and DOMS is one of the main things that discourages people.

About footnotes. There are 80 footnotes in this document. Click to make them pop up without losing your place. There are two types: more interesting extra content,1 and boring reference stuff.2 Try one!

Rub it out?

The other muscle soreness! DOMS is a short-term condition occuring only after intense exercise, but muscles have other problems. Muscle knots — myofascial trigger points — are a factor in most of the world’s aches and pains. As biologically puzzling as DOMS,3 they can cause strong pain that often spreads in confusing patterns, and they grow like weeds around other painful problems and injuries, making them interesting and tricky. Misdiagnosis is epidemic.

When I was a Registered Massage Therapist, patients often hoped for DOMS relief, or some advice on how to avoid it.4

Alas, there was nothing5 I could do for them. It’s mostly a myth — one of many massage myths — that DOMS can be effectively treated by massage … or anything else. Believe me, I’ve tried — my personal experimentation will be described below. Massage therapists certainly often claim to be able to do so, but without evidence or justification. Like many health care myths, it’s not too loudly touted, just carelessly repeated and perpetuated (often in major publications, *cough*6). But medical science can barely even explain DOMS, let alone treat it — it seems to be nature’s little tax on exercise, which everyone must pay. There are no shortcuts through it. DOMS is indomitable.

DOMS timing: just how delayed is it?

Although a delay of a day is typical, there seems to be a large natural range for just how delayed DOMS can be. It may start as quickly as “right away” for particularly intense and/or long workouts and as late as a full day. (The speed of onset and the severity are often related, but not necessarily.) The peak of pain is the more obviously “delayed” part of DOMS, because it almost exclusively occurs the next day, and sometimes even as far out as the middle of the second day after the workout. Personally, I’ve even had the odd third day that seemed at least as bad as the second.

This variability is probably due to both the complex biology of DOMS itself and/or the complications caused by other kinds of pain problems. For instance, if one is generally inflamed or sensitized — two common broad explanations for widespread body pain — it stands to reason that it would either accelerate the timing, or at least obscure it.

Nothing causes DOMS more reliably in me than racquet sports. My forearm extensor muscles get viciously sore for days, every time. Partly because I rarely play more than a couple times per summer.

What triggers delayed-onset muscle soreness?

Exercise or other physical stresses outside your normal range of intensity — anything you aren’t used to. Even extremely well-conditioned athletes can get DOMS, if they train harder than usual. But as muscles get familiar with a specific stress, they quickly adapt and react much less strongly: repeated bout effect ( RBE ). Any theory of DOMS is going to have to account for RBE (which is very interesting, see Deyhle, also discussed below in the inflammation section).

But how far outside your exercise comfort zone can you wander before DOMS strikes? That seems to depend on many unknown factors. Exactly what it takes to make people how sore is one of the main mysteries of DOMS. But some things are fairly certain:

“Eccentric” contractions — controlled elongation — cause DOMS far more readily than concentric contractions.7

Genetics is probably a factor. Although it is a universal experience, the sensitivity to the effect, and its intensity, vary considerably from one person to the next.

It can be aggravated by other stresses. For instance, if you become significantly dehydrated, DOMS will be worse. In fact, it can be triggered by virtually any significant physical or metabolic stress. The most interesting example: a strong massage. And the weirdest? Fear of pain can predict how bad DOMS will be!8

Dancing fool Maybe the worst DOMS I ever had was after a night of dancing and, yes, a little “head banging.” (I grew up in a Canadian logging town; AC/DC & Metallica were like gods to us.) Even a little head banging can be hard on neck muscles. I could barely lift my head off my pillow for 3 days.

The (unclear) causes of delayed-onset muscle soreness

The exact cause of DOMS is unknown. Like most relatively minor aches and pains, understanding DOMS is an extremely low priority in medical science. That’s surprising when you consider the impact DOMS has on elite athletes — a group of people whose performance is collectively worth trillions of dollars, and obsessively optimized, seemingly sparing no expense. You’d think this topic, at least, would get more scientific attention. And yet we don’t really know why DOMS happens.

It is usually described as the consequence of mechanical and/or metabolic stress9 … which isn’t saying much. What else would cause DOMS? Financial stress?

DOMS is probably a slower, longer-lasting chemical cousin of the simpler, briefer “burn” of intense effort — and the chemistry of the burn is surprisingly fresh science. What exactly causes it? Which molecules? According to Pollak et al, it’s protons, lactate, and ATP — and only in concert.10 “There was essentially no response whatsoever to the individual metabolites,” explains Alex Hutchinson for Runners’ World, “so the receptors apparently respond only to the synergistic combination of all three.” It’s complicated, in other words.

Just as the burn only happens when certain molecules get mixed up, burn alone does not doom one to DOMS. But that burn is probably a pre-requisite for DOMS. For the full DOMS effect, you probably need more chemistry (more than you want).

DOMS may be a mild form of metabolic poisoning called “rhabdomyolysis” — or just “ rhabdo ” for short (and for the rest of this article). True rhabdo is a medical emergency in which the kidneys are poisoned by myoglobin from muscle crush injuries.11 But many physical and metabolic stresses cause milder rhabdo-like states — including intense exercise, and probably the strongest massage as well.12 There are many well-documented cases of exertional or “white collar” rhabdo.13 That term was coined by Knochel in 1990 because rhabdo was striking recreationally extreme athletes — people with white-collar jobs who voluntarily work themselves into a sorry state.14 You could also call it (for fun) recreational rhabdo. Another well-known source of rhabdo cases is military boot camp: “large numbers of [recruits] may have myoglobinemia … .”15 After a bit of browsing through the literature, I have the impression that you could be rhabdo-ized by an especially hard sneeze.

The mildest rhabdo — a comparatively benign cocktail of waste metabolites and by-products of tissue damage — is probably one of the reasons why we feel generally cruddy after intense physical stresses.

But although “rhabdo” is a fun word, it doesn’t really say much. We know remarkably little about the biology of that state.16 Surprisingly little specific can be said about how DOMS works. For instance, “microtrauma” certainly gets said anyway, but it’s just another way of saying mechanical stress. And while it does seem plausible that intense exercise could cause microtrauma specifically — and the idea is prevalent, and it is probably involved to some extent — the research does not support this idea nearly as well as you might assume, and some even contradicts it.1718

What about metabolic stress?

“Metabolic stress” is a more sophisticated way of looking at the cause of DOMS. Muscle cells are like little chemical factories, and they produce some unpleasant by-products — and probably more of them when working at intensities they haven’t had a chance to adapt to. It seems plausible enough in general terms, but it’s a tricky concept to pin down.

What constitutes metabolic stress, exactly? Researchers have spent decades identifying various obscure molecules produced by cells during exercise, but are any of these molecules necessarily a sign of painful metabolic wear and tear? Just because a cell produces a substance during exercise does not mean it is metabolically frazzled, or that you are going to hurt. In any event, no one has been able to find a link between DOMS and any specific biological markers.1920

Surely lactic acid is the culprit! Lactic acid is not a dead-end, “bad” metabolic waste product, and it does not cause post-exercise soreness. This is a pernicious and seemingly un-killable myth. It originated with “one of the classic mistakes in the history of science,” according to George Brooks, a Berkeley physiologist. I will not give the myth any further airtime here. See Gina Kolata’s clear overview in the New York Times, or a concise professional summary by Robergs in Experimental Physiology. For a deeper and geekier, but excellent read, see Dr. Goodwin’s entertaining rant about the prevalence of the lactate myth in the 2012 summer Olympics coverage.

For demonstration purposes, we’ll dip deeper into this subject on just one molecule. “Free radicals” or “reactive oxygen species” are unstable, highly reactive molecules that are an unavoidable by-product of cellular metabolism. “There is growing evidence that reactive oxygen species (ROS) are involved in [DOMS].”21 Unfortunately, although free radicals have an even better name than “rhabdo,” which sounds just nasty enough to cause DOMS, they don’t have the decency to actually be present in great numbers when DOMS is at its worst. Instead, “the increase [of free radicals] occurred after the peak decline in muscle function and DOMS.”22 In other words, ROS may be involved — they probably are involved — but the relationship is indirect and unclear at best. They could even simply be a by-product of some other, hidden culprit.

Are you on fire? Inflammation in DOMS

Evidence indicates that there is little or no inflammation present in DOMS in the first place.2324 Or (counter-intuitively) that there’s inflammation all right, but it’s not the cause of the pain: a 2015 study showed the bizarre result that inflammation holds steady or even increases after subsequent workouts.25 This suggests that exercise soreness is not caused by inflammation, but by something else that inflammation actually prevents.

That’s so weird/important, let’s repeat and rephrase: the evidence suggests that some minor inflammation present in DOMS is a reaction to whatever’s actually causing the pain. This is potentially an explanation for the repeated bout effect. Here’s the sequence of hypothetical events:

unfamiliar exercise stirs up “something” (and this is uncomfortable) the immune system reacts to that (inflammation), and suppresses it over 2-4 days a few days later you do the same exercise … but this time your immune system is ready for it, so when “something” gets stirred up, it is much more effectively dealt with

And then there’s neurology!

Neurology never comes up when professionals talk DOMS. It’s really not on anyone’s radar, but it should be.

We’ve established that DOMS isn’t likely a direct result of microtrauma or metabolic stress, and inflammation is either absent or “it’s complicated.” Nothing demonstrates that more clearly than an 2011 study, which showed that it can actually spread — probably via a neurological mechanism — to adjacent muscles groups that were not exercised at all.26 This is probably closely related to a similar phenomenon, a known-unknown about muscle called “non-local muscle fatigue” — which is fatigue in the muscles you did not exercise.27

That’s really strange. Very strange indeed. Thus DOMS may well often feel much worse and more extensive to some patients than it “should” feel … and with an explanation that isn’t really on anyone’s radar.

The biology of pain is never really straightforward, even when it appears to be. ~ “Reconceptualising pain according to modern pain science”, Lorimer Moseley

We should especially be thinking more about neurology because of a series of Japanese studies since 2010 showing that the pain is related to neurotrophic factors: substances secreted by muscles cells that goose nerve growth.28293031 A simpler way to say this would just be nerve growing pains. Exercise develops our nerves, and apparently that’s uncomfortable.

Not only does this account for the repeated bout effect, it might also explain the curious findings of Ayles et al.

All of this was shown in rats, not humans, and all by the same group of researchers, so it’s not time to uncork the champagne and declare victory quite yet. But it’s extremely interesting and promising, and it gets better: based on this theory, the Japanese researchers did demonstrate that the development of DOMS was “completely suppressed” by a drug that stifles neurotrophic factors. Yahtzee! And what was that drug? I’ll return to it below in the discussion of medications.

The bad news: the many ineffective treatments for delayed onset muscle soreness

Since we still don’t (yet) know what causes DOMS, it’s unsurprising that anything like a cure has yet to be discovered. Even if we understood it, we still might not be able to do anything about it. Certainly almost nothing tried so far seems to be the least bit impressive, but a couple promising exceptions follow this section. A 2003 review of the subject concluded, “Cryotherapy, stretching, homeopathy,32 ultrasound and electrical current modalities have demonstrated no effect on the alleviation of muscle soreness or other DOMS symptoms.”33 Other reviews have similarly dismissive conclusions.34 Here’s a list of popular but mostly unconvincing treatments, with relevant evidence for each in the footnotes:

ultrasound3536

warmup or light exercise, “working it out”3738

protein supplementation, namely… glutamine and arginine39 leucine, isoleucine, valine (the branched-chain amino acids)40

stretching4142

icing (not just ineffective,4344 but possibly even harmful4546)

transcutaneous electrical nerve stimulation (TENS)4748

Epsom salts49

drinking extra water50

cherry juice (it’s the antixodants, see)51

compression garments (tight elastic sleeves)52

And then there are some marginally more promising treatment options that still fall well short of actually being “proven” or practical. They are only somewhat promising at best. Each of these is covered in more detail below:

NSAIDs and COX-2 inhibitors

massage

vibration

vitamin D

curcumin

fish oils

heat

treatment for insomnia

Generally speaking, there is a broad consensus that nothing really decisively helps DOMS,53 and the best way to prevent it is … just get it over with. In other words, only DOMS prevents DOMS!

Except maybe Indian food. And heat. And maybe sunshine and fish. Or Vitamin I. The next few sections are devoted to a few of the slightly more promising options.

Vitamin I: the effects of ibuprofen on pain, prevention, function, and healing

Ibuprofen (and other anti-inflammatory drugs, the NSAIDS) have been shown to modestly reduce the pain of DOMS.5455 (Note that popular topical NSAIDs, like Voltaren®, may be mostly ineffective,56 especially on big muscles, probably because the drug can’t be absorbed into deep enough tissue).

pain? yes

weakness? no

prevention? no!

healing time? it’s complicated

Anti-inflammatories for function

NSAIDS do not reduce the muscle weakness that goes along with the pain. For instance, if you had severe DOMS in your quadriceps, taking ibuprofen would probably reduce your pain, but you would still not be able to jump as high as usual.

Anti-inflammatories for prevention

They don’t prevent DOMS either, not even a little bit. The science is quite clear on this point: a 2006 experiment tested the effect of ibuprofen on hard core marathoners.57 The results were so strongly at odds with beliefs that Aschwanden used the research as a main example in an article about how hard it is to get people to accept new evidence:58

Among runners of ultra-long-distance races, ibuprofen use is so common that when scientist David Nieman tried to study the drug’s use at the Western States Endurance Run in California’s Sierra Nevada mountains he could hardly find participants willing to run the grueling 100-mile race without it. Nieman, director of the Human Performance Lab at Appalachian State University, eventually did recruit the subjects he needed for the study, comparing pain and inflammation in runners who took ibuprofen during the race with those who didn’t, and the results were unequivocal. Ibuprofen failed to reduce muscle pain or soreness, and blood tests revealed that ibuprofen takers actually experienced greater levels of inflammation than those who eschewed the drug. “There is absolutely no reason for runners to be using ibuprofen,” Nieman says. The following year, Nieman returned to the Western States race and presented his findings to runners. Afterward, he asked whether his study results would change their habits. The answer was a resounding no. “They really, really think it’s helping,” Nieman says. “Even in the face of data showing that it doesn’t help, they still use it.”

Fascinating!

Anti-inflammatories and healing

“We can put a man on the moon,” but we still don’t really know what non-steroidal anti-inflammatories do for injured/sore muscles other than relieve pain. It’s nice to think they might facilitate healing, but the opposite is just as possible: they might impair healing by suppressing aspects of inflammation that are necessary for healing.

The role of inflammation in DOMS is extremely unclear (understatement). As discussed above, Deyhle et al showed that inflammation actually increases as the pain fades away — an extremely odd finding. So it’s complicated! No wonder the evidence on the effects of NSAIDs is so mixed.

A 2017 review of 41 relevant scientific papers, the first of its kind, concluded that NSAIDs may cause a “small to medium” drop in various signs of injury in the short term, compared to recovery without NSAIDs.59 Curiously, the effect is more pronounced in the lower body.

Also odd: recovery impairment was detected, but only in animals. So don’t feed your dog NSAIDs after a hard evening of fetch.

Most of the studies reviewed by Morelli et al had a low risk of bias (which is a bit unusual in musculoskeletal medicine), and yet the eight studies that did have a higher risk of bias account for a substantial amount of the benefit detected. Take them out and the positive result starts to look downright unimpressive: a minor effect, on the margin of statistical significance. Arguably those studies should not have been included at all. So the question still does not seem to be clearly answered, and the healing benefits are unpredictable and/or modest at best.

COX-2 inhibitors: an anti-inflammatory used for something else

Earlier I introduced a series of Japanese rat studies that suggest DOMS is basically “neurological growing pains” (summarized by Mizumura et al). This was substantiated by preventing DOMS using COX-2 inhibitors, which specifically inhibit neurotrophic growth factors. This is not their primary purpose: COX-2 inhibitors are anti-inflammatory meds by nature, a much-maligned type of NSAID with major safety issues, and the only remaining drug of this type for sale in the US is Celebrex (celecoxib). If Celebrex can be clearly shown to prevent DOMS in humans, that’s a huge deal, not because it’s a viable treatment — preventing DOMS almost certainly isn’t valuable enough to be worth the side effects of COX-2 inhibitors — but because it would prove the mechanism of DOMS … a profound knowledge upgrade.

The heat hope

Everyone will be pleased to know that one study (predictably European) showed some benefits to hot tubbing, specifically “warm underwater jet massage”60 — aaaah. However, it was a small and flawed piece of research — and most people know from personal experience that a soak in a hot tub may “take the edge off it,” but this hardly constitutes a miracle cure for DOMS. This evidence is too weak to take to the bank.

In 2006, we got some better science news: surprisingly good results in treating DOMS in the low back with a “heat wrap,” a wearable device that applies heat for hours at a time.61 It’s another small study, just 17 test subjects, but more persuasive.

Eureka? Proof needs more data, but this makes it well worth trying heat on your sore muscles after exercise. Happy heating! See the thermotherapy guide.

The fish hope

Fish oil has shown some potential to aid with recovery from exercise.62 The evidence is not compelling, but it’s noteworthy, especially the apparent effect on strength and ROM recovery.

But I’d say the take-home message is to eat more fish, rather than fish oil in capsules — because there’s plenty of evidence that fish are better for you than fish oil pills.

The curcumin hope

Updates like this are what PainScience.com is all about: this isn’t just a stale old blog post debunking DOMS treatments! I’m still updating it, well over a decade after I first published it. And I’m very pleased to be updating it with something promising.

Curcumin is the interesting molecule in the bright orange South Indian spice, turmeric. It “exerts potent anti-inflammatory effects.” Although we’ve just discussed evidence that inflammation may not be a factor in DOMS, here’s some new evidence that it is: in a 2015 study, “curcumin caused moderate to large reductions in pain” in 17 men with very sore leg muscles.63 It also helped some aspects of strength loss. The effect size here passes the “impress me” test. These results constitute the only really good science news about any kind of treatment for DOMS. Now it just needs to be replicated! Which is why I won’t give it any more attention at this time: this is good, promising news, but it absolutely needs to be verified.

Note that curcumin is poorly absorbed without other agents such as black pepper extract (piperine). There are several completely unproven products that promise better absorption by various means, so caveat emptor.

Massage, DOMS, and a lot of irony

What of massage therapy? We’ve got to deal with massage in more detail, because it’s the king of treatments presumed effective. And it’s reputation got a big boost in early 2018 from a low-quality meta-analysis (more on Dupuy et al below).

Oh, irony Massage can cause some soreness & malaise, rather than relieving it.

Massage therapists and enthusiasts often claim DOMS prevention and cure as a benefit of massage. Unfortunately, what evidence there is to support this damns it with faint praise — it doesn’t work well enough to be impressive64 — and plenty of evidence goes the other way,65 including my own careful personal testing. At best, massage has mild therapeutic effects on DOMS that are largely mitigated or cancelled out by mild side effects.

It’s more likely that massage actually causes some soreness and malaise itself — just like exercise does. The sensations are incredibly similar.

A 2007 survey of 100 massage patients66 found that 10% of 100 patients receiving massage therapy reported “some minor discomfort” in the day following treatment. This would mainly be the familiar slight soreness that is common after a massage, known as “post-massage soreness and malaise” ( PMSM ) — and although 10% is plenty, it is almost certainly too small a number.67

But the irony deepens! Massage as a DOMS treatment is also often “explained” with a myth — that massage detoxifies. This is an unsavory association. Detox language in health care is usually bollocks. In the case of massage, the detoxification claim never made much sense, there’s no evidence for it, and if anything there’s evidence that massage is somewhat toxifying — probably by causing a little rhabdo. I make that case in a lot of detail in another article:

Poisoned by Massage Rather than being DE-toxifying, deep tissue massage may actually cause a slightly toxic situation ~ 6,500 words

Is there any hope? Some other way that massage could help DOMS? Even while possibly causing some at the same time? No explanation other than detoxification has ever been suggested … until just recently.

Can massage reduce DOMS by reducing inflammation?

No. (You can go to the next section now, if you like.) As of early 2012, there’s a candidate for a new explanation of how massage works … or a new myth. It’s a lot more likely that it’s a new myth.

According to the headlines and the researchers themselves, massage supposedly “reduces inflammation,” based on a gene profiling experiment that got a lot of press. (A lot.) It’s bollocks. Unfortunately, the researchers tried to explain a therapeutic effect that is either an illusion or a minor outcome, and they generally over-interpreted the significance of a handful of proteins. The upshot is that it’s much ado about nothing and doesn’t really change our understanding of massaging DOMS.68

Although this fact was distinctly under-emphasized, the study identified literally hundreds of changes in gene expression caused by exercise — compared to just five changes caused by massage. The take-home message from that is simple: exercise changes cellular behaviour, massage does not. That is not really any kind of a surprise.

Enough theory! Does massage help DOMS or not?

We don’t have to know how something works to test to see if it works. And massage for DOMS has been tested. The upshot is that the results are mixed and underwhelming. Damned with faint praise.

In 1998 — around the time I was starting my training as a massage therapist, actually — E. Ernst published a review of papers on this subject in the British Journal of Sports Medicine .69 Ernst concluded that, “Massage therapy may be a promising treatment for DOMS. Definitive studies are warranted.”70 That sounded like good news for massage therapy! However, actually reading the paper discouraged me.

Digging into the details always seems to have that effect.

Ernst found only seven studies worth considering, and most of these had “serious methodological flaws” and “very small sample sizes.” Of the seven, three are inconclusive or show no effect on massage therapy on DOMS, and four “imply a positive symptomatic effect” or a “positive trend.” I was not particularly impressed by any of those positive effects or trends — they all seemed ambiguous to me, even if you ignore the “serious methodological flaws.” I could not come to the same optimistic-sounding conclusion that Mr. Ernst did.

Since that time, I have not seen any new studies or evidence to alter my opinion. Another review in 2003 judged massage to be “less promising” than anti-inflammatories, which are themselves so unremarkable.71 A 2008 review found “moderate data supporting its use” — wow — continuing the pattern of damning DOMS-massage with faint praise, and pulling a barely-positive conclusion out of weak data.72 Readers have been telling me for years now that they believe there is new evidence that “massage works” for DOMS, but when I go looking, I can’t find any data that seems the least bit impressive. For example, one the best studies I could find, a 2006 paper by Zainuddin et al, found barely statistically significant evidence of modest pain relief only, possibly quite brief, with no effect on the weakness whatsoever (no study has ever found that).73 And that’s roughly as good as it gets. When people tell me that there is “good evidence” that massage is effective for DOMS, this is what they’re talking about. I acknowledge that some of the evidence is indeed “positive” — that is undeniable — but it fails to impress.

Another (bad) reason people believe that massage might help DOMS is because of a misleading science story from 2012. Supposedly researchers discovered that massage reduces inflammation. Even if this was clearly relevant to the biology of DOMS (and it’s not), the conclusion was hype: there’s no way that reseach demonstrated any such thing.

Since we don’t know much about what causes DOMS, and we don’t know much about how massage therapy works (and probably never will), it’s difficult to even guess about how massage therapy is supposed to help. While it does seem likely that massage therapy probably has some positive effect on DOMS, those effects are likely to be limited, and to vary widely depending on the therapist, the individual, and the circumstances. And so I remain skeptical that massage therapy can be claimed to generally prevent or reduce the intensity of DOMS, let alone actually “cure” it. Massage therapy should not be promoted or purchased for this reason. Fortunately, there are plenty of other reasons to have massage therapy: see Why Massage Therapy?

And there are also plenty of other myths! There’s a full list of them in the related reading section below.

That troublesome 2018 study that declared victory for massage therapy

In early 2018, many massage therapists jumped to cite a new scientific paper, Dupuy et al74 because it seemed to confirm their bias75 that massage helps post-exercise muscle soreness. And no wonder! The conclusion reads:

Massage seems to be the most effective method for reducing DOMS and perceived fatigue.

So massage therapists were tripping over themselves sharing it on Facebook, retweeting it, and posting it on their clinic blogs. Such conclusions are literally good for business. “From the Department of the Obvious,” one MT quipped. Another triumphantly declared of this article, “PainScience.com gets it wrong again!” As if one new publication beats all the analysis of the evidence I’ve published here over the years.

Dupuy et al is a classic “garbage in, garbage out” meta-analysis that establishes nothing … except, perhaps, the opposite of the “positive” conclusion . Just read the fine print! There’s a strong and classic pattern of publication bias in the data, with better quality studies finding nothing of interest, and the shittier ones consistently skewing towards the positive.

Alex Hutchinson wrote about this paper for Outside, and included a terrific summary of how publication bias is exposed by funnel plots (a must-read for anyone trying to make sense of research). This kind of thing is the legacy of decades of publish-or-perish pressure in academia. Recovery science is a mess, most of the studies are just junk, and so most meta-analyses are too… and there’s a lot of them. John Ioannidis:76

The production of systematic reviews and meta-analyses has reached epidemic proportions. Possibly, the large majority of produced systematic reviews and meta-analyses are unnecessary, misleading, and/or conflicted.

This one is so useless that I wouldn’t even be citing it here if it hadn’t made “headlines.” I’m bringing it up only for the sake of hype control. It’s not good for anything except being a fine example of the clutteration of medical science with low quality meta-analyses.

From the Lab of Me: a massage experiment with a sample size of one

Purpose: To test massage-aided recovery from delayed onset (post-exercise) muscle soreness. Systemic steam heating — I have a lovely steam room at my disposal — was used as an adjunctive therapy.

Methods: I totally thrashed my biceps at the gym, deliberately pushing into the danger zone to generate wicked DOMS. It worked a charm: my guns were mighty sore by the end of the day. Soreness spiked with the slightest contraction, making it easy to evaluate. The next morning, sensitivity was equally savage on both sides. In a toasty steam room, I massaged the crap out of my left upper arm for several minutes, using strong deep palm stroking, which was super unpleasant. The things I do for science! Then I compared soreness at regular intervals by flexing simultaneously.

Results: Soreness in my biceps was identical at all testing points after massage: 5 and 20 minutes later, and about 1, 6, 12, 24, 36, 48 and 72 hours later. The soreness was extremely intense from 24 to 48 hours, fading quickly after that — the usual pattern of recovery. And entirely symmetrical.

Conclusion: Neither strong massage or heat produced any effect on DOMS in this little guinea pig.

Meaner, longer DOMS as a symptom of other health problems

DOMS can be made worse by some other health problems — possibly quite a few of them. Although DOMS is not caused by medical vulnerabilities per se, it’s possible that it would be a non-issue otherwise. It’s even possible that it’s a canary in the coal mine: particularly fierce DOMS might actually be one of the only symptoms of a medical vulnerability. But how can you tell? Pain is totally subjective and it’s nearly impossible to tell if your DOMS is actually excessive. Comparing notes with other people is difficult, because people love to complain and may bitterly vouch for the severity of their own DOMS — and, for all you know, maybe they really are having a problem of their own.

There’s really no way to know, except to do your best to judge the severity of your DOMS, and see if it appears to be part of a pattern of other symptoms. For instance, you might suspect vitamin D deficiency if your DOMS seems a bit nuts and your head is sweating a lot (a more distinctive symptom of vitamin D deficiency), and you live in northern British Columbia and rarely see the sun.

DOMS is just a part of a broader spectrum of challenges to “exercise recovery.” There are many possible reasons why people might struggle to recover from exercise. It might just be more acute fatigue. For instance, another deficiency, iron, would cause fatigue and a variety of other symptoms — but it probably wouldn’t make DOMS worse. But there are undoubtedly other problems, like sleep disturbance (discussed below), that will aggravate DOMS specifically.

Most health problems that will aggravate DOMS are either relatively obvious, or nearly impossible to diagnose, or untreatable. For the purposes of this article, I’m going to focus on just a couple problems (for now) that seem most worth considering: vitamin D deficiency and insomnia. Both are common, both can be helped, with a clear benefit to DOMS.

Vitamin D deficiency

Inadequate vitamin D is probably more common than once suspected — at least 1 in 20 people in the lowest estimates,77 and possibly many more.78 It can cause subtle widespread pain that may be misdiagnosed as fibromyalgia and/or chronic fatigue syndrome, including symptoms like muscle and bone aching, fatigue and weakness, lower pain threshold, and — here’s the punchline — fiercer DOMS that takes longer to resolve.

There’s no direct evidence available on this topic (surprise surprise). Despite that, the indirect evidence is actually far stronger than most of the direct evidence available on other topics. We have at least three hard facts for premises: vitamin D deficiency really is common, definitely makes DOMS worse, and (obviously) can be treated with appropriate supplementation.

If you have the impression that you’re struggling to recover from exercise, that the consequences of a workout are out of proportion, vitamin D deficiency is worth investigating. For more information, see Vitamin D for Pain.

Insomnia and sleep disturbance in DOMS

Sleep deprivation makes pain worse, muscle pain in particular, and probably DOMS as well. There is no direct scientific evidence of this that I am aware of. However, anyone who has ever been severely sleep deprived will tell you that it causes a distinctive and unpleasant feeling of “fragility” which seems quite likely to make one more vulnerable to DOMS.

Ultimate is an intense Frisbee sport that can make almost anyone wickedly sore.

I have an example of sleep-deprivation induced DOMS from personal experience: The first ultimates games of the season have always been an ordeal. They are followed by 3-5 days of harsh DOMS. But in 2011 I started the season in unusually good physical condition, thanks to months of sprint intervals and strength training. For the first time ever, I was not sore after my first games of the summer. And my DOMS-immunity continued in week two, so it didn’t seem to be a fluke. That was then followed by some nasty sleep deprivation and jet lag. I suffered a great deal of it for two weeks — before, during and after a holiday to Amsterdam. When I returned to Vancouver and played ultimate again, I was really blasted sore. Quite extreme.

Coincidence? I think not!

Vibration

Vibration therapy is widely regarded as “stimulatory,” often with the implication of subtle but exotic effects on healing, much like ultrasound (which is just vibration therapy at much higher frequencies). While low-frequency vibration — AKA “jiggling” — may have some intriguing effects on biology, these are mostly uncharted waters, and it’s clear that some popular uses are already failing to pass fair scientific tests. For instance, the trendiest application of vibration therapy trying to boost strength training results, which probably doesn’t work, according to a 2014 review.79

As of spring 2019, the only available scientific review of vibration for DOMS is complete junk.80 Despite that stain on the literature, there are still a handful of trials of interest. I’ll use Broadbent et al as an example. It seems mostly fine, if a bit underpowered.

It was a test of vibration therapy on sore muscles in runners. 29 recreational runners were asked to run downhill for 40-minutes, which is about as reliable a recipe for DOMS as can be devised for a bunch of typical recreational runners. Only the legs of elite runners are ready for a challenge like that, and not all of them. Half of the runners were given “once-daily sessions of vibration-therapy on the upper and lower legs,” and the other received no treatment. Vibrated muscles were less sore and had fewer blood markers associated with soreness. Which gets my attention. The authors concluded:

Vibration therapy reduces muscle soreness and IL6. It may stimulate lymphocyte and neutrophil responses and may be a useful modality in treating muscle inflammation.

Certainly intriguing, but not conclusive. There are a few others like this, but they are clearly inadequate. There might be something here, but — as usual — we won’t know until some larger, better tests are finally done. Meanwhile, I wouldn’t hesitate to vibrate my sore muscles, because it’s kinda fun and obviously harmless (other than the time/cost of the gadgets).

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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.

Appendix: Dueling massage anecdotes: A typical testimonial versus my own personal experiment with massage for delayed-onset muscle soreness

In early 2012 I made one of my once-in-a-while appearances on SkepticNorth.ca. I’m in their roster of reserve guest myth busters. This time Scott Gavura (the Skeptical Pharmacist) recruited me early one morning for some short-notice debunkery of a sloppy Globe & Mail piece on delayed onset muscle soreness (DOMS). I felt like the Batman getting the bat signal, but instead of being a billionaire martial artist gadget freak called to fight crime, I’m a middle-class amateur athlete gadget freak called on to fight … bad science journalism. An endless chore. Just like Batman’s.

The Globe & Mail recommended Epsom salts, massage, and light exercise for muscle soreness. None of those will do anything or much, just like every other alleged treatment for DOMS. As covered thoroughly in this article, there really is no cure for DOMS but time. Inevitably, we saw some anecdotal evidence to the contrary in the comments. OCTriathlete stood up for massage with this story:

I was lucky enough to receive a leg massage from a family member who is educated in massage but not a professional. However, I was unlucky in that the massage was interrupted after only one leg was complete!! The next day the leg that received the attention was only hinting at the sensation of the heavy workout the previous day. The leg that missed out? It was DEEPLY sore for 2 days. So there you have it—my own little scientific (however unintentional) experiment.

Lucky him! I’ve done that experiment intentionally and casually a half dozen times in my life before getting a little more serious about it — see the section “From the Lab of Me” — and I’ve never observed the slightest difference. If only. And in the early days I did it with the greatest of optimism and the full-on mental bias of someone paying his rent by selling that therapy. I love massage for many reasons, but recovering from a harsh workout has never been one of them.

O anecdote — how I want to strangle thee

I wonder what would happen if we took Occam’s razor to OCTriathlete’s anecdote. What is more likely?

Massage has an incredibly potent effect on recovery — almost perfect pain elimination, the likes of which, if true, should revolutionize athletic recovery. But this miraculous effect has never been demonstrated in a fair test, and not for lack of trying.

OCTriathlete simply had one leg that was more thrashed than the other to begin with for some reason. Or: memory and the story have come to support an attractive idea. As memory and stories do.

I know which bullet point I’d bet on.

Maybe OCTriathlete truly got a benefit. I’m being very skeptical, yes, but I’m not actually saying that he couldn’t have actually enjoyed a nice effect. Physiology differs. The evidence on massage for DOMS isn’t entirely negative — just mostly, and distinctly underwhelming where it’s positive. There could be interesting cases on the edge of that bell curve, and OCTriathelete could be one of them — slightly pulling up an unimpressive average.

But … Occam’s razor cuts hard and deep on a story like his.

If anecdotal evidence were actually reliable, then most folk medicine would still be the best medicine available today. If there are a lot of testimonials for something, people like to say that there “must be something to it,” but not only is that not true, it’s practically the opposite of true: testimonials are actually a sign of the wrong kind of thinking about medicine. The history of anecdotal evidence has given us almost every silly belief you have ever heard of: every naked superstition and outrageously dangerous quackery has had its zealots, converts, and emphatic testimonials, sometimes in extremely large numbers. People have sworn that snake oils work even as they were being (literally) destroyed by them. For a whole bunch of wonderfully entertaining examples, spend a happy hour listening to Caustic Soda’s terrific Quackery episode.

And what are those all beliefs are based on? Exclusively?

Anecdotes!

Perhaps a personal experiment like mine — an antimonial — is a just a little bit of an anecdote antidote. I love massage, but I’m not kidding myself: if it helps DOMS at all, it doesn’t help most people much.

Illustration used with the kind permission of Zach Weiner, of Saturday Morning Breakfast Cereal. Thanks, Zach!

Related Reading

The major myths about massage therapy are:

The complete list of dubious ideas in massage therapy is much larger. See my general massage science article. Or you can listen to me talk about it for an hour (interview).

And massage is still awesome! It’s important to understand the myths, but there’s more to massage. Are you an ethical, progressive, science-loving massage therapist? Is all this debunking causing a crisis of faith in your profession? This one’s for you: Reassurance for Massage Therapists: How ethical, progressive, science-respecting massage therapists can thrive in a profession badly polluted with nonsense.

Notes