Has a coach, trainer or therapist “screened” you for injury risk and dysfunctional movement patterns? The Functional Movement Screen (FMS) is a set of seven physical tests of coordination and strength, especially “core” strength, invented in 1997 and now in widespread use around the world. It was originally proposed as a trouble-detection system, which is baked into the name: it’s a “screen.”
Its use in the wild seems to over-reach this stated purpose.
FMS founder Lee Burton wrote in March, “The biggest critique we have gotten over the years is the lack of research to support use of the FMS” but “more and more research is becoming available relating to its scope and effectiveness.”1 I am not so sure that the evidence available to date is persuasive — the opposite, I fear — but meanwhile FMS is being promoted as though its powers are proven. Despite Burton’s statement, I think the marketing cart may be in front of the research horse.2
This isn’t (so far) a thorough review of FMS: it is focussed on the use (or abuse) of FMS as a way to diagnose the average athlete or patient.3 I do not think FMS is a “scam” or a proven failure. I do think there is cause for concern.
A “screen” has a specific meaning in health care. It is not a diagnostic tool: it is just for detecting individuals who need diagnosis. This is a common concept in health care — think “mammogram” or “prostate exam”4 — but not so much in sport and rehabilitation. The complexities and ethics of screening are a bit exotic, normally debated in the context of vast public health initiatives.
Anoop Balachandran explains how screening is fundamentally a different ethical beast than diagnosis, because you are telling basically healthy people what might be wrong with them, and that raises the stakes5 (specifically the real risk of nocebo6):
…The validity of screens should be of the highest quality since you are “labeling” people and hence we should have very solid proof that people will be better off in the long run. When someone scores less than the cut off in the FMS, you tell them their chance of getting injured is extremely high. This is a great way to get someone to move less or have fear of movement or spend his or her time and money trying to fix it with their trainer.
Anoop Balachandran, MSc Exercise Physiology, MSc Human Performance
Nevertheless, it was a fine idea to try to introduce FMS into the world of performance and rehab. It would have been a good idea even if that was not the actual original intent. Truly, we could use a good screen. It’s just not clear that FMS is actually being used that way. Indeed, it’s seems clear that it’s not.
So either FMS should change its name, or it should be used as a screen — to determine that “something is wrong here” or “something is still wrong here” — and not to figure out what is actually wrong. But in the real world, FMS is often promoted as a tool that can “detect” biomechanical problems and therefore justify training or treatment methods to “correct” them. Again, founder Lee Burton: “FMS is designed to identify movement pattern dysfunctions, thereby helping create the best possible intervention.”7
That’s no screen — that’s diagnosis!
And the “best possible intervention” is often expensive, of course — athletes and sports teams may invest heavily in following advice that is based substantially on FMS assessments.
FMS certification and exaggeration of its benefits is also often used to create an impression of diagnostic competency in professionals — coaches and trainers — who are trying to seem more like therapists and should not be diagnosing at all (or even seem to be). Athletes and fitness buffs are often “enablers” in this regard.8
This is a general problem with the industry, of course, but FMS certification is a prominent example.
A little searching on the internet can quickly scare up examples of FMS being used diagnostically. In just a few seconds, I found a chiropractic website with the claim that FMS “uncovers limitations and asymmetries in the movements of healthy individuals.” It goes on “Corrective exercises can then be prescribed to overcome these deficiencies.”9 The overconfident use of FMS to justify specific treatment is blatant here.
Or look at this amusing example of overconfident promotion of FMS: big diagnostic and treatment promises, to the tune of cheesy 80s rock anthem “Eye of the Tiger.” (Admittedly, it’s a nostalgic classic. My foot taps…) In the video, modestly titled FMS: Get Your Best Body, a chiropractor demonstrates FMS and explains:10
Depending on your score and asymmetrical results from left to right side I can determine your non-painful dysfunction. We correct that and you become a better athlete. Stronger, more flexible, stable, mobile and powerful. Oh, and you can get out of chronic pain…
Are these just isolated cases of FMS hype? Perhaps FMS training and certification would minimize such overstatement? Perhaps. There may well be FMS practitioners who overstate the claims of FMS, going beyond its intended use. But FMS certification is granted by a company that promotes it with language surprisingly similar to the examples above. The official FMS website is generally heavy with promotional language and light on the science:11
…the FMS readily identifies functional limitations and asymmetries … used to target problems … directly linked to the most beneficial corrective exercises to restore mechanically sound movement patterns … identify those exercises that will be most effective to restore proper movement …
“About” page of FunctionalMovement.com12
Visit the FunctionalMovement.com, have a look around, and judge for yourself. Does it seem like they are promoting a screening tool with modest goals and appropriately limited scope? Or a diagnostic tool “directly linked” to treatment?
The use of FMS as a screen and a diagnostic tool has been particularly problematic because “normal” test results had never been defined. A low FMS score supposedly means that you are more likely to get hurt, but … lower than what? FMS needs a baseline — or even several of them, for a variety of well-defined populations.
A small new study in International Journal of Sports Physical Therapy recently set out to get the numbers for normal.13 According to Schneiders et al the idea that FMS has diagnostic power is (emphasis mine):
…based on the assumption that identifiable biomechanical deficits in fundamental movement patterns have the potential to limit performance and render the athlete susceptible to injury.
However, their experiment could not even detect a difference in test results in people who had actually been injured recently. The results
demonstrated no significant differences on the composite score between individuals who had an injury during the 6 last months and for those who had not.
Past injury is probably a risk factor for future injuries — for instance, the reasons for the original injury may persist and cause re-injury, or a new injury. If FMS cannot detect any sign of recent injuries, it seems unlikely that it can detect the risk of future injuries, let alone be used as a basis for a specific therapy.
This is not surprising. In general, rehab science has generally been failing for decades to nail down correlations between even the most obvious-seeming “biomechanical bogeymen” and common injuries, let alone the smoking gun of a true cause. Even if there are biomechanical causes of pain and injury — and doubtless there are a some — I wouldn’t expect a set of physical tests to reveal them in an exact or reliable way.
Anoop Balachandran criticizes the rationale for FMS in more detail:14
Why should mechanical stress causes by “faulty movement patterns” always “lead to microtrauma and injury”? Why can’t tissues just positively adapt and get stronger just like a normal biological tissue? If indeed faulty movement patterns were the cause of injury, all those cerebral palsy patients, stroke victims, people with neurological disorders and amputees should be in complete pain. There are double amputees who run faster than most of us and still feel no pain. The compensations and asymmetries are 100% in these amputees and they should be crying out loud in pain than running around. Maybe that movement pattern is “ideal” for them and the tissues have adapted to it.
Anoop Balachandran, MSc Exercise Physiology, MSc Human Performance
FMS is classic example of structuralism — the excessive preoccupation with biomechanical factors in injury and pain.15 In particular, it depends on the faddish notion that “core strength” is important, an idea that has been harshly criticized by experts16 and has generally failed to live up to its reputation.17 At best, the value of core strength remains controversial. At worst, it’s been a serious red herring in the fitness and therapy industry.
Structuralism typically depends on complex chains of reasoning that are only as strong as their weakest links. For FMS to deliver what it promises, all the of the following links must be sound:
If FMS practitioners can do all that — and do it reliably — then they can deliver what they are promising.
The first version of this article was written in 2011, mostly hype-griping, and it went untouched for three years while FMS promoters carried on making claims about a “growing body of research,” of course. I’m only aware of a single study showing that FMS (and/or a related screening method, Y-balance) worked okay as a screen — that is, the results showed the tests could identify athletes who were at risk of injury.18
The research as a whole wasn’t persuasive before … and maybe things have gotten worse since.
A summer 2014 paper by Whiteside et al echoes all my original concerns, but with harder data.19 The researchers focussed on the accuracy of FMS grading in particular: “virtually no investigations have probed the accuracy of FMS grades assigned by a manual tester.” So they probed it! They compared “the FMS scores assigned by a certified FMS tester to those measured by an objective inertial-based motion capture system.” Alas for FMS, the results were “poor,” which is exactly what I’ve been betting on all along.>
Manual grading may not provide a valid measurement instrument. The levels of agreement between the two grading methods were poor in all six FMS exercises. It appears that manual grading of the FMS is confounded by vague grading criteria.
The discussion section of the article is detailed, readable, and full of ominous understatement. “Dubious grading presents a concern for FMS clientele,” they write. They graciously allow that, with better objective criteria, FMS grading might “improve to acceptable levels.” I’m shocked, simply shocked, to learn that FMS practitioners might be a tad overconfident!Meanwhile, FMS testers are officially encouraged to aim for lower scores when in doubt, but in this test, even under scrutiny, apparently they didn’t have much self-doubt, consistently scoring “0.54 points higher than the IMU system.” (I’m shocked, simply shocked, to learn that FMS practitioners might be a tad overconfident!) The authors also point out that FMS has not only failed to reliably forecast injuries, but all FMS predictions may be “a product of specious grading.” Which is hardly surprising, since FMS fails to take into account “several factors that contribute to musculoskeletal injury.” These concerns must be addressed “before the FMS can be considered a reliable injury screening tool.”
Clearly more research is needed — of course! Naturally! But it’s worse than that:
The high potential for subjective and/or inaccurate grading implies that standard procedures must be developed before FMS performance and injury rates can be conclusively studied.
Before it can be studied. They seem to be saying that not only is the cart is still in front of the FMS horse, the horse may now be falling well behind. FMS research so far may be a bit of a write-off, because it can’t inform us without better criteria, and everyone should probably just go back to the drawing board and try again. Which suggests that this article is still reasonably sound after three years without an update.
A caution is not a dismissal: I cannot conclude that FMS has no value. All I can do here is raise a concern that the FMS is being applied inappropriately by many trainers, and seems to be resting on a number of questionable and untested assumptions. The burden of proof is (still) on FMS proponents to substantiate their claims, and the evidence so far mostly shows that they haven’t even really gotten started. Please take it with a grain of salt if anyone tries to tell you what’s wrong with you based on FMS testing.
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.
Special thanks to Scot Morrison, CSCS, student DPT; and Jason Silvernail, DPT, DSc, FAAOMPT, for their assistance in preparing this article. Thanks also to other members of SomaSimple.com, who also had many useful suggestions.
— Minor science update.
— Added new section, based on Whiteside. A little miscellaneous modernizing and editing.
— Added numerous footnotes. Added a new section, “A long, fragile chain of reasoning.”
This study tested two popular exercise options for chronic low back pain — core coordination, core strengthening — and compared them to a neutral third type, general exercise. Over a hundred participants worked with “experienced physical therapists” once a week for eight weeks. This is a particularly good test, because it is a good approximation of what a motivated patient might do: paying for eight weekly sessions of training is a greater and more disciplined effort than many people make, and yet still reasonably affordable and achievable.
Pain and disability were measured before and after, and at a one year follow-up. Unfortunately, there were no differences: “This study gave no evidence that 8 treatments with individually instructed motor control exercises or sling exercises were superior to general exercises for chronic low back pain.”
Perhaps more training would have yielded better results, but it’s hard to imagine that it would be worth the additional expense and effort for what would surely be a minor difference. And perhaps a different exercise therapy would have performed better, but the ones tested here are exactly the kind of thing that is almost always recommended to patients — so if there’s a better kind of exercise therapy, it’s certainly unknown and unproven.BACK TO TEXT
This looks like some positive evidence for the power of the FMS screen to predict injury. My money is still on the null, and I don’t think any of the other evidence to date is all that persuasive yet (because Whiteside et al).
But if, in the end, good evidence says the screen works, then bully for FMS! Almost all my gripes with FMS concern over-reaching its stated purpose as a screen and using it as a diagnostic/prescriptive tool. If it does actually work as a screen, I will be the first in line to say, “Congratulations, FMS!” But I’m not holding my breath.BACK TO TEXT