Massage guns — the latest overpriced and overhyped fitness product.
Around December of 2020 when these things hit their peak popularity, multiple massage
gun companies started emailing me, offering to sponsor a video if I reviewed their product.
And while I’ve personally tried these products in the past, I wasn’t willing to take on
any of them as sponsors until I researched them.
If I endorse something, I want to know it’s legit, and unfortunately, my research did
not support the claims that advertisers made, so I turned down their offers.
But I figured I’d share the results with you all, and more importantly share my research
process.
It’s the same process I use when researching scripts for SciShow, especially if I’m trying
to suss out whether health products actually do anything or not.
So do massage guns work?
Well, it depends on what you mean by work.
Right away when we’re evaluating whether a product’s claim is true, we need to clarify
what the claim /is/.
If I go on Amazon and look at the product descriptions for massage guns, I see a few
claims, the most common of which is that these tools reduce recovery time, increase range
of motion, promote blood flow, and relieve chronic pain.
So the first thing I do is search on PubMed and Google Scholar and start looking for any
systematic reviews about massage guns — or percussive therapy, as it’s called in literature.
If you’ve never heard of reviews before, they’re an attempt to systematically analyze,
critique, and synthesize all scientific information about a specific topic into one, up to date
source.
It’s an attempt to answer the question “What is everything we know about this thing?”.
By doing that, we eliminate the ability for people to cherry pick studies that support
their claim.
There weren’t any systematic reviews on PubMed, but through Google Scholar I found
something called a preprint literature review, which means it hasn’t been peer reviewed
yet.
That’s still helpful because now I’ve got a bunch of potentially interesting sources,
but because it wasn’t peer reviewed, and because it was written by an undergrad student,
I’ll read the narrative more critically.
Next, I widened my scope to include all research formats in PubMed, and I found that, as of
July 2021, there were only two peer reviewed studies that looked at people who used these
tools, both of which were published in 2020.
The first article was a case study published in the Physical Therapy and Rehabilitation
Journal in 2020.
Case studies are basically stories — they document noteworthy and interesting cases.
If you’ve seen a ChubbyEmu video, those are mostly case studies.
This one tells the story of a 25 year old woman who got rhabdomyolysis, a potentially
lethal condition where injured muscles break down and dissolve.
After training on a stationary bike for 30 minutes, her coach used a massage gun on her
thighs assuming that it would relax her muscles.
He wasn’t a trained massage therapist and didn’t take a medical history before using
it.
It turns out, his client was anemic, which might have predisposed her to rhabdo.
Now, overexercising can be one of the triggers of rhabdomyolysis, but this woman only did
a few minutes on a stationary bike and had tolerated it well before.
So the author suggests that the mechanical trauma from the percussion gun caused her
muscles to break down — although we’ll never know exactly how the trainer used it.
Fortunately, after a few weeks in the hospital, she recovered.
But reasonably, the article concluded with “hey, these things are potentially dangerous
if used wrong”.
But it’s a case study, so that doesn’t mean everyone’s muscles will
start falling apart, just that it has happened.
Our second article was a randomized controlled trial, where the researchers split participants
into two groups, one of which gets the treatment, one of which doesn’t.
This last group is called the Control Group.
This is considered the gold standard of experiments since any difference between the groups is
likely because of the treatment.
This article was published in the Journal of Sports Science and Medicine and looked
at whether massage guns could improve range of motion.
Perfect.
This is one of the claims made by most advertisers.
The researchers recruited 16 young men to come in on two separate days and measured
their dorsiflexion range of motion.
Then they gave them either 5 minutes of massage gun treatment to their calf, or no treatment
at all.
Then they measured dorsiflexion again to see if there was any change — they also measured
maximum force production with a special machine.
They found that the treatment group’s dorsiflexion increased by an average of 5.4 degrees, while
there was no difference in the control group.
Force production was unaffected either way, so they suggested that this kind of treatment
might be appropriate during warmups to increase range of motion.
While that supports at least one of the claims we talked about, we need to be careful of
what it doesn’t support.
They only measured acute effects in this study — what happened right after treatment.
We’d need to repeat this on the order of weeks to say whether consistent massage gun
treatments increase range of motion over the long term.
Plus they also only used young, healthy men in their study, and only measured one joint.
That doesn’t automatically mean that this treatment will work for older adults or for
more complex joints like hips and spines.
Plus, (and this is my favorite part) this same research group did this exact same experiment
in 2019 except they tested static stretching instead of massage guns, and they saw the
same effect on range of motion.
The free intervention was just as effective at increasing acute range of motion as the
$300 option.
Now, those are the two peer reviewed studies I found on PubMed, and if I were conducting
a proper systematic review or writing a SciShow script, I’d check out some other databases.
But for now I’m just getting a lay of the land.
And clearly, these two studies don’t lend a ton of support to our big advertising claims
from the beginning which is normal.
It’s common for advertisers to steal claims from related therapies and repurpose it for
their own.
Massage gun sellers base their claims on the research done on manual massage therapy, with
the /assumption/ that the same conclusions for massage can be applied to massage guns.
Now, that’s not how science works.
While these modalities are /intended/ to do the same thing, we don’t /know/ that they
accomplish the same thing unless we study it.
In our little research so far, we’ve only found evidence for an improvement in range
of motion, but I’m still curious about this big claim — muscle recovery.
So I looked for reviews on massage therapy and recovery and found way more results.
Which is understandable, massage therapy has been around for thousands of years while massage
guns have not.
A review from 2008 in the Clinical Journal of Sports Medicine looked at muscle recovery
in human subjects who performed strenuous exercise and got a massage at some point — perfect
for what we’re looking for.
Muscle recovery was usually measured by having the participant rate how sore or painful their
muscles felt, and might have included data about range of motion or peak torque production.
All in all, they included 27 articles, 10 of which were those high quality randomized
controlled trials.
The 17 others studies were case series — basically where a researcher said “I massaged a bunch
of people and here’s what I saw”.
Case series almost never use control groups.
But each study was different.
They used different massage techniques, and massaged different muscles for different lengths
of time.
Plus, very few studies measured an objective measure of soreness — most asked for a subjective
rating of pain.
The other elephant in the room is that participants know if they’re getting massaged or not,
and that might bias them.
Likewise, the researchers know who got massaged.
And in a traditional RCT, neither the participants nor the researchers would know which treatment
the participants were getting until the very end, this is called blinding.
So while the writers of the review wanted to find out whether massage helped with muscle
recovery, the studies were just too different to learn anything conclusive.
But they did pull out some useful info.
Like that the most recovery happened if the treatment was within a two hour window after
exercise.
The duration of the massage, ranging from 5 minutes to 30 minutes didn’t impact recovery.
A more recent review has come out since then.
It was published in the British Medical Journal Open Sport and Exercise Medicine in 2020,
and not only did it include all the more recent studies, but it also ran what’s called a
meta-analysis.
Basically, it compiles all the studies on a topic and pools their data together to find
stronger patterns using the new, bigger pool of participants.
And just like a review, they have to be pretty specific about the questions they’re asking.
This meta analysis looked at studies that measured the effect of massage on sport performance
including strength, flexibility, and recovery.
All in all, they looked at 12 randomized controlled trials and 17 randomized crossover studies,
which encompassed over a thousand participants.
When combining all that data together, they found that massage had no effect on most metrics
of performance like sprint time, endurance, or strength but significantly improved flexibility
scores by about 7%.
And while massage didn’t have any effect on muscle fatigue, it did significantly reduce
delayed onset muscle soreness, or DOMS by 13% — this is probably the thing that advertisers
will point to to justify the “promotes recovery” claim.
But again, that’s a subjective measure, and one of the studies was a heavy outlier,
which inflates the average.
And bringing it back to the original premise of the video, this meta analysis only speaks
to massage therapy.
We can’t assume this translates to massage guns.
So, the final thing I look for when checking out these products or therapies is a proposed
mechanism for how it works physiologically.
Luckily, I found an article published in 2005 that reviewed the proposed mechanisms behind
massage.
They collected a bunch of journal articles and found that proposed mechanisms fell into
4 categories: biomechanical, physiological, neurological, and psychophysiological mechanisms.
And right away, there was limited evidence to support most of them.
For instance, people have proposed that massage decreases active muscle stiffness, but /no/
studies have ever checked.
Others proposed it decreased /passive/ stiffness, but only one study checked, and it didn’t
have any significant effect past the control group.
Meanwhile, some studies found a positive effect of massage on range of motion but often they
didn’t have appropriate control groups or they couldn’t blind their subjects, like
I mentioned earlier.
Plus, when compared to static stretching, massage was only able to increase dorsiflexion
while static stretching increased range of motion across all lower extremity measurements.
So massage is fine, but so is stretching.
In the physiological category, there /is/ good evidence that massage increases skin
and muscle temperature a little bit, but the big suspected mechanism, increased blood flow
/didn’t/ have a ton of good evidence.
Most studies used small sample sizes and didn’t analyze any statistics.
Plus, some of the more advanced tools that physiologists use to measure blood flow, tend
to overestimate blood flow.
The best research (ie, the studies with the least amount of design problems) showed no
change in the blood flow to muscles after massage.
So massage might work because it provides heat.
but we can’t say it increases blood flow with any certainty.
The psychological mechanisms were probably the most compelling category.
Most studies used an already-established test of anxiety, the State-Trait Anxiety Indicator
or STAI, but they suffer from design issues like not having a control group.
And if there was another group, it might not be a control.
Oftentimes, the goal of a research project was to compare two interventions, like massage
and meditation.
And if the researchers split the participants into two invention groups: half get massage,
half meditate, those aren't control groups!
From that experiment you can say that the massage group had lower anxiety /compared/
to the meditation group, but you can’t generalize and say that massage lowers anxiety for a
bigger group of people.
So to summarize this review, people have used massage for thousands of years, and liked
it, so they kept using it.
But because of /how/ we study massage, we still don’t know 100% how it works.
And bringing this all back, we can’t assume that research on massage therapy translates
to a handheld device.
Okay so what’s the takeaway?
If you like using massage guns and find a benefit in them personally, awesome, have
fun.
I’m glad you’re finding a way to enjoy your corporeal form before you collapse and
return to dust.
Like I mentioned, there’s more research available on some of the other databases,
but based on my research so far, the evidence that /does exist/ only supports improvements
in range of motion in one muscle group, which you can achieve to the same degree by stretching.
Which is free!
So my end message is this: if you’re on the fence about buying one of these things,
save your money.
They're not a miracle cure for anything
And with all that money you just saved on a massage gun, consider supporting me on Patreon
where you get early access to my scripts and videos, suggest topics, and support this channel.
Otherwise I always appreciate when you subscribe, like the video, all the other youtube stuff.
Have fun, be good.
Thanks for watching.