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Can Functional Movement Screening detect injury risk? New science casts doubt.

The Functional Movement Screen (FMS)

The popular screening system for athletes failed to detect recent injuries in a new study

3,000 words, published 2011, updated Oct 2nd, 2013
by Paul Ingraham, Vancouver, Canadabio
I am a science writer, the Assistant Editor of ScienceBasedMedicine.org, and a former Registered Massage Therapist with a decade of experience treating tough pain cases. I’ve written hundreds of articles and several books, and I’m known for sassy, skeptical, referenced analysis and a huge bibliography. I am a runner and ultimate player, and live in beautiful downtown Vancouver, Canada. • full bioabout SaveYourself.ca

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 particularly persuasive, 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.

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.

Functional Movement Screening in theory

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 stakes4 (specifically the real risk of nocebo5):

…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.

Functional Movement Screening in practice

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.”6

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 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.7

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.”8 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:9

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:10

…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.com11

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 Functional Movement Screen fails to detect recent injury in a new study

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.12 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:13

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

And now for some good news about FMS

On the bright side, the Schneiders study did confirm that the FMS testing is reliable (inter-rater reliability14): 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 poor15). 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.

A long, fragile chain of reasoning

FMS is classic example of structuralism — the excessive preoccupation with biomechanical factors in injury and pain.16 In particular, it depends on the faddish notion that “core strength” is important, an idea that has been harshly criticized by experts17 and has generally failed to live up to its reputation.18 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.

Caveat emptor

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.

About Paul Ingraham

I am a science writer, former massage therapist, and assistant editor of Science-Based Medicine. 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 and Google, but mostly 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.

What’s New In this Article?

Thursday, July 14, 2011 — Added numerous footnotes. Added a new section, “A long, fragile chain of reasoning.”

Notes

  1. Burton, Lee. Research Statement and Review. functionalmovement.com Mar 7, 2011. BACK TO TEXT
  2. Schneiders et al. Functional movement screen normative values in a young, active population. International Journal of Sports Physical Therapy. 2011. PubMed #21713227. BACK TO TEXT
  3. Both of these well-known and little-loved procedures are used to flag individual who need further assessment. In no way can a mammogram or prostate exam actually diagnose. The distinction is clear in these cases. (Note: in Canada, we have screening mammograms; in other countries, they are used used diagnostically. So perhaps it isn’t the best example for an international audience. But is also just another way of emphasizing the difference between screening and diagnosing.) BACK TO TEXT
  4. Balachandran, Anoop. Functional Movement Screen: Is it Really a Screen? exercisebiology.com, January 21, 2011. BACK TO TEXT
  5. “Nocebo” is Latin for “I shall harm” (which I think would make a great supervillain slogan). It refers to the harmful effect of … nothing but the belief in or fear of a harmful effect. Give someone a sugar pill and then convince them you actually just fed them a deadly poison, and you will probably witness a robust nocebo effect. A common funny-if-it’s-not-you nocebo in general medicine is the terror of “beets in the toilet”: people eat beets, and then think there’s blood in the toilet, and call 911. Nocebo is a real thing, and not to be messed with. It is one of the chief hazards of excessive X-raying and MRI scans, for instance: showing people hard evidence of problems that often aren’t actually a problem. A screening test that reveals alleged problems might do it too. BACK TO TEXT
  6. Burton, Mar 2011, Op. Cit. BACK TO TEXT
  7. It’s truly amazing how much credit amateurs will give to medically unqualified and barely-regulated professionals like trainers, fitness instructors, and coaches. It can be difficult for a personal trainer, for instance, to resist the temptation to answer a question as if they have the knowledge that a client wants to give them credit for. My mother is a fitness instructor, and routinely amuses me with tales of the questions that class participants will ask her in all earnestness: real medical questions! Admirably, she refuses to even speculate, and decivisely refers them to actual health care professionals — which is exactly what a fitness instructor should do. BACK TO TEXT
  8. Functional Movement Screen. chiropractorincincinnati.net. No publication date. Accessed 7/11/11. BACK TO TEXT
  9. “Dr. Perry.” Functional Movement Screen: Get Your Best Body. YouTube.com, April 4, 2009, accessed 7/13/11. BACK TO TEXT
  10. FMS Research Articles functionalmovement.com, no publication date, accessed 7/09/11. This page lists four items. One is a blog post reviewing research, but not reporting on new research. BACK TO TEXT
  11. What is FMS? functionalmovement.com, no publication date, accessed 7/09/11. BACK TO TEXT
  12. Schneiders et al., op. cit. BACK TO TEXT
  13. Balachandran, Anoop. Functional Movement Screen. exercisebiology.com, November 29, 2008. BACK TO TEXT
  14. For more detail, see another article on SaveYourself.ca, Is Diagnosis for Pain Problems Reliable? Reliability science shows that health professionals can’t agree on many popular theories about why you’re in pain. BACK TO TEXT
  15. French et al. Reliability of chiropractic methods commonly used to detect manipulable lesions in patients with chronic low-back pain. Journal of Manipulative & Physiological Therapeutics. 2000. PubMed #10820295.

    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
  16. SY Ingraham. Your Back Is Not “Out” and Your Leg Length is Fine: Debunking the obsession with alignment, posture, and other biomechanical factors as a major cause of pain. SaveYourself.ca. 12931 words. BACK TO TEXT
  17. Lederman. The Myth of Core Stability. Journal of Bodywork & Movement Therapies. 2010. PubMed #20006294. BACK TO TEXT
  18. Unsgaard-Tøndel et al. Motor Control Exercises, Sling Exercises, and General Exercises for Patients With Chronic Low Back Pain: A Randomized Controlled Trial With 1-Year Follow-up. Physical Therapy. 2010. PubMed #20671099.

    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