SaveYourself.ca • Sensible advice for aches, pains & injuries
Can Functional Movement Screening detect injury risk? New science casts doubt.
published 7/09/11, updated 7/14/11
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 word. 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 particularly persuasive, but meanwhile FMS is being promoted as though its powers are proven. Despite Burton’s statement, I think the marketing cart is being put well before the research horse.
This isn’t a thorough review of FMS: it is focussed on the phenomenon of FMS being used as a way to diagnose the average athlete or patient, and the possible implications of some new recent research in International Journal of Sports Physical Therapy.2 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”3 — 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 stakes:4
…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 actively 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.”5
That’s not a 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 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, because it is unethical and dangerous. Athletes and fitness buffs are often “enablers” in this regard.6
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.”7 The overconfident use of FMS to justify specific treatment is blatant here.
Or look at this amusing example of overconfident abuse of FMS: big diagnostic and treatment promises, to the tune of cheesy 80s rock anthem “Eye of the Tiger.” In the video, modestly titled FMS: Get Your Best Body, a chiropractor demonstrates FMS and confidently explains:8
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 hype and over-statement of the benefits of FMS? Perhaps FMS training and certification is needed to minimize such overstatement? Perhaps. There may well be FMS practitioners who dramatically overstate the claims of FMS, going far 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 an expensive commercial web presence that is generally heavy with promotional language and light on the science:9
…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.com10
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, high-quality new study in International Journal of Sports Physical Therapy recently set out to get the numbers for normal.11 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 future risk, 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:12
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
On the bright side, the Schneiders study did confirm that the FMS testing is reliable (inter-rater reliability13): different professionals get similar results when assessing the same person. I was surprised by this. I expected the opposite!
Reliability is typically poor with commercialized diagnostic systems and methods. Inter-rater reliability is poor for the huge majority of manual therapy assessment methods ever tested (for instance, inter-rater reliability of chiropractic assessment is poor14). However, it appears that interpretations of FMS results are reasonably consistent, which is great to see.
And there’s more good news: Schneiders et al also did produce what the intended: good baseline FMS results for average active people. That’s a valuable step in helping clinicians — and future researchers — start to understand the meaning of FMS results — if any. You’ll see this paper cited a lot in virtually all FMS research going forward, I suspect. That’s why I chose to focus on it.
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.
A caution is not a dismissal: I cannot conclude that FMS has no value. There is no conclusion here except concern. FMS testing is not proven. It is not disproven either … but it is resting on a number of questionable and untested assumptions. The burden of proof is on FMS proponents to substantiate their claims, and it appears that FMS promoters are actively seeking research confirmation of their claims. Until they get it, however, please take it with a grain of salt if anyone tries to tell you what’s wrong with you based on FMS testing.
Thursday, July 14, 2011 — Added numerous footnotes. Added a new section, “A long, fragile chain of reasoning.”
BACK TO TEXT Comments: I do enjoy reliability studies, and this is one of my favourites. Three chiropractors were given twenty patients with chronic low back pain to assess, using a complete range of common chiropractic diagnostic techniques, the works. Incredibly, assessing only a handful of lumbar joints, the chiropractors agreed which joints needed adjustment only about a quarter of the time (just barely better than guessing). That’s an oversimplification, but true in spirit: they couldn’t agree much, and researchers concluded that all of these chiropractic diagnostic procedures “should not be seen … to provide reliable information concerning where to direct a manipulative procedure.” BACK TO TEXT BACK TO TEXT Comments: 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.