Hip weakness is a rising-star of running injury risk factors. “Dead butt syndrome” has become a popular scapegoat, especially the two kinds of runner’s knee, iliotibial band syndrome (ITBS) and patellofemoral syndrome (PFPS). I don’t think that runners should get excited about it. The evidence is not compelling enough to “believe” in hip strengthening as a prevention or therapy for any condition. In general, no kind of strength training is known to prevent sports injuries, especially overuse injuries — though that claim is often made, often by citing one scientific paper that doesn’t actually support the point.1
However, it’s an interesting subject, and the theory is not completely without merit or promise. It’s worth exploring, and keeping tabs on. But it’s mostly a story of a pet theory that has gotten blown way out of proportion based on inadequate evidence — a good modern example of a type of science failure that plagues musculoskeletal and sports medicine.
In a dazzling display of irony, the September, 2009, issue of Runner’s World both quoted me as an expert debunking conventional wisdom about stretching … & yet uncritically promoted a new myth for a new generation of runners: the hip-strengthening myth.
The origins of the hip weakness hype
The buzz began in 2000, when Fredericson et al reported in the Clinical Journal of Sports Medicine that “long distance runners with ITBS have weaker hip abduction strength in the affected leg compared with their unaffected leg and unaffected long-distance runners.”2 Better yet, they found (or seemed to) that “symptom improvement … parallels improvement in hip abductor strength.”
This wasn’t a perfect study. It didn’t prove that weak hip muscles actually cause iliotibial band syndrome, or that strengthening them will cure it. The researchers showed only that — maybe — these things tend to go together: ITBS and hip weakness, sitting in a tree, kay-eye-es-es-eye-en-gee.
It was intriguing.
Phase 2: The Hypening
A month later, someone else finally did: Niemuth et al published “Hip muscle weakness and overuse injuries in recreational runners.”5 Although they found the same association as Fredericson et al, that really was all they were looking for, the sample size was small, and they didn’t prove a causal relationship, which they freely and specifically admitted (“ … no cause-and-effect relationship has been established”).
In 2006, Lori Bolgla and a team at the University of Kentucky joined the fray. They studied various muscle strength and function measurements in relationship to patellofemoral pain syndrome,6 finding only a “moderate” association between that condition and weakness in one minor hip movement (external rotation), but conspicuously did not find a significant difference in the “main” hip strength movement: hip abduction.7 The authors clearly state — and no surprise here — that “we were unable to determine if hip weakness was a cause or a result.”
Still no smoking gun here. A definite absence of gunsmoke.
In 2007, Ferber et al completed another little study.8 Despite never being published, both the researchers and media made way too much of the results — a damning example of science-by-news-release. “I think this is a good news study for people who are living with chronic running pain,” said Dr. Ferber. “You can do something about it.” Such optimism! Reporting on it for the Calgary Herald, Trent Edwards wrote (no longer available online): “While most running injuries happen in the knees and lower legs, it turns out their root cause is almost always weak hip muscles.” The whole thing has a weird eureka tone, as though a great mystery had been officially solved. But Dr. Ferber was clearly ahead of himself. Everyone loves a root cause!
Patients bring such media reports to me in a tizzy of optimism, and I have to be the wet blanket. I have to explain that — just like with every other Holy Grail of biomechanical theorizing — the jury is not just “out,” the trial had hardly even begun. A dozen necessary studies were still missing in 2007. Reaching a conclusion based on the evidence back then wasn’t just difficult, it was impossible in principle.
Not much else happened for three more years, while the hype marched on and the researchers continue to promote their hypothesis.910 The promotion is obvious in a general review of running injury mechanisms in 2009,11 and then again in 2010, in a paper which did not even present good evidence of correlation, let alone causation.12 Those were paltry scientific contributions, and I dropped the topic in a bit of disgust at that point. And so could you. Skip this next bit if you’re already convinced/disappointed, because there’s very little to add, and what little there is mostly just confirms that this is a dead end. But I am obliged to be thorough, because that’s what you paid for.
Like cold fusion, but with smaller press conferences
When there are signs that a scientist may be just a little too fond of their own exciting hypothesis, eventually other scientists come along and try to find the same thing … and usually fail.
The first example of failed replication of the hip weakness hypothesis was in 2007, just as the hype was really surging. Grau et al said everything I’ve already said above, but more formally, with a paper titled, “Hip abductor weakness is not the cause for iliotibial band syndrome.”14 They did a tiny test of strengthening to see if it would help, comparing hip strength in ten runners with and ten without IT band syndrome. There were no meaningful differences, and “strengthening of hip abductors seems to have little effect.”
Which was followed by years of scientific silence. During which time tens of thousands of runners were told by well-intentioned clinicians to strengthen their hips to prevent/treat ITBS. They all thought they were practicing not just evidence-based medicine, but bleeding edge EBM. Ruh roh, Raggy!
Fast forward all the way to 2014: a small paper reported only one minor part of hip strength was detectably weak in injured runners — internal rotation — and it was hardly a big difference.15 “Teensy” is the technical term for that kind of difference. And while internal rotation is indeed part of the biomechanical equation, it’s hardly what people are thinking of when they think of hip strength. “Obscure” is the next adjective that comes to my mind.16
There’s only one more scrap of science I know of, in 2015, yet another small one (of course), reporting a modest weakness in hip strength — the more familiar kind, abduction — but only in runners with previous IT band syndrome.17 Runners with current ITBS … well, that was just a big fat nothing burger. No link at all. And the link with previous cases hints that what little weakness they found might well be a long-term consequence of being injured, not a cause.
There’s no other science to report on except a few review papers, formally trying to make sense of the same inadequate evidence I’ve been weighing here, some of them concluding that there may or might or could be a link possibly, perhaps. But others, like Louw et al, have more honestly concluding that, duh:
The literature is inconclusive with regards to muscle strength deficits in runners with a history of ITBS.18
So the whole thing just reeks of “pet theory” syndrome, and it’s extremely unlikely that hip weakness causes IT band syndrome. And therefore it is also extremely unlikely that strengthening hips will prevent or treat it.
Why not strengthen your hips anyway? Who doesn’t want stronger hips?
You probably have better things to do than progressively load obscure muscles that probably have nothing to do with ITBS. But I suppose if it was me, if my own case of ITBS made a comeback and got really stubborn, I might do it anyway. It’s certainly not going to hurt anything. I can’t endorse it, but I don’t object to it either.
Just go in with your eyes wide open. You might be wasting your time. Just like five hundred soldiers who already tried it on your behalf …
Here’s one more bit of discouraging science I held back back for a punchline. This was not a small experiment: it was a huge test of a thousand soldiers that failed to show any (injury prevention) benefit to hip strengthening. Although one study is never enough to settle an issue, this one almost could. The results were published in 2008 in the American Journal of Sports Medicine.19 500 soldiers did both stretching and strengthening exercises chosen to try to prevent overuse knee injuries. Hip abduction was included, specifically because of the hype about hip strengthening: because of the prominent papers pushing it as a possible risk factor. 500 more soldiers did no exercises for comparison.
Results: the injury rates in the two groups were … almost identical. And what difference there was between them was (slightly) different in the wrong direction. The group that did no exercises actually had slightly fewer injures: 48 injuries instead of 50.
Generic hip strengthening is definitely not preventing IT band syndrome. And if it’s not preventing it, it’s not going to treat it either.
About Paul Ingraham
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.
What’s new in this article?
2018 — Additional improvements following the February reboot of this excerpt, tying up some loose ends, adding some colour and detail.
2018 — Completely rebooted. This article is now a near-verbatim excerpt from the IT band syndrome book.
- PS Patellofemoral Pain & the Vastus Medialis Myth — Can just one quarter of the quadriceps be the key to anterior knee pain?
- PS Patellofemoral Tracking Syndrome — The beating heart of the conventional wisdom about patellofemoral pain is mostly nonsense
- PS The Runners Knee Diagnostic Checklist — How to tell the difference between the two most common kinds of runner’s knee
- PS Massage Therapy for Your Quads — Perfect Spot No. 8, another one for runners, the distal vastus lateralis of the quadriceps group
- PS Is Running on Pavement Risky? — Hard-surface running may be risk factor for running injuries like patellofemoral pain, IT band syndrome, shin splints, and plantar fasciitis
- PS Should You Get A Lube Job for Your Arthritic Knee? — Reviewing the science of injecting artificial synovial fluid, especially for patellofemoral pain
- PS Do Women Get More Knee Pain? — The relationship between gender and knee pain, especially runner’s knee (IT band syndrome, patellofemoral pain)
- PS What Can a Runner With Knee Pain Do at the Gym? — Some training options and considerations for runners (and others) with overuse injuries of the knee
- PS Iliotibial Band & Patellofemoral Pain Defy Biomechanical Expectations — The science shows that you can’t blame runner’s knee on structural quirks that seem like “obvious” problems
- PS Kinesio Taping Review — A quick analysis of that colourful therapy tape that was so popular at the Olympics. Does it help?
- Lauersen JB, Bertelsen DM, Andersen LB. The effectiveness of exercise interventions to prevent sports injuries: a systematic review and meta-analysis of randomised controlled trials. Br J Sports Med. 2014 Jun;48(11):871–7. PubMed #24100287. ❐ PainSci #53226. ❐
This meta-analysis is the best reference available to support a general claim that resistance training will prevent injuries (traumatic or overuse). Unfortunately, “the best” is not very good: the authors’ conclusion about injury prevention is based on data from just four studies of questionable/limited relevance, and there is contrary evidence. Although strengthening might prevent injuries, it remains an untested hypothesis, and this citation just does not provide meaningful support for it.BACK TO TEXT
- Fredericson M, Cookingham CL, Chaudhari AM, et al. Hip abductor weakness in distance runners with iliotibial band syndrome. Clin J Sport Med. 2000;10(3):169–175. BACK TO TEXT
- For instance, hip muscles may react to ITBS pain by “going limp,” and then they recover as the condition resolves. Though it seems at first to fly in the face of Fredericson’s results, the idea is defensible, even plausible. For instance, Mense and Simons write, “Physiologic studies show that muscle pain tends to inhibit, not facilitate, reflex contractical activity of the same muscle … ” (Mense synopsizing Johnson). BACK TO TEXT
- Fredericson M, Wolf C. Iliotibial band syndrome in runners: innovations in treatment. Sports Med. 2005;35(5):451–459. PubMed #15896092. ❐ “ … weakness or inhibition of the lateral gluteal muscles is a causative factor … ” BACK TO TEXT
- Niemuth PE, Johnson RJ, Myers MJ, Thieman TJ. Hip muscle weakness and overuse injuries in recreational runners. Clin J Sport Med. 2005;15:14–21.
OBJECTIVE: To test for differences in strength of 6 muscle groups of the hip on the involved leg in recreational runners with injuries compared with the uninvolved leg and a control group of noninjured runners.
DESIGN: Descriptive analysis.
SETTING: Three outpatient physical therapy clinics in the Minneapolis/St. Paul metropolitan area.
PARTICIPANTS: Thirty recreational runners (17 female, 13 male) experiencing a single leg overuse injury that presented for treatment between June and September 2002. Thirty noninjured runners (16 female, 14 male) randomly selected from a pool of 46 volunteers from a distance running club served as controls.
MAIN OUTCOME MEASURES: Self-report demographic information on running habits, leg dominance demonstrated by preferred kicking leg, and injury information. Muscle strength of the 6 major muscle groups of the hip was recorded using a hand-held dynamometer. The highest value of 2 trials was used, and strength values were normalized to body mass(2/3).
RESULTS: Results comparing the injured and noninjured groups showed that leg dominance did not influence the leg of injury (chi(2)(1) = 0.134; P = 0.71). Correlations for internal reliability of muscle measurements between trials 1 and 2 with the hand-held dynamometer ranged from 0.80 to 0.90 for the 6 muscle groups measured, and all P values were less than 0.0001. No significant side-to-side differences in hip group muscle strength were found in the noninjured runners (P = 0.62-0.93). Among the injured runners, the injured side hip abductor (P = 0.0003) and flexor muscle groups (P = 0.026) were significantly weaker than the noninjured side. In addition, the injured side hip adductor muscle group was significantly stronger (P = 0.010) than the noninjured side. Duration of symptoms was not a contributing factor to the extent of injury as measured by muscle strength imbalance between injured and uninjured sides.
CONCLUSIONS: Although no cause-and-effect relationship has been established, this is the first study to show an association between hip abductor, adductor, and flexor muscle group strength imbalance and lower extremity overuse injuries in runners. Because most running injuries are multifaceted in nature, areas secondary to the site of pain, such as hip muscle groups exhibiting strength imbalances, must also be considered to gain favorable outcomes for injured runners. The addition of strengthening exercises to specifically identified weak hip muscles may offer better treatment results in patients with running injuries.
BACK TO TEXT
- Not IT band syndrome, mind. The hip weakness hypothesis has been just as big a deal for patellofemoral pain syndrome as it has for ITBS, maybe bigger. This first study of the link between hip weakness and PFPS really added to the hype. But for the rest of the story I will ignore the PFPS research and just focus on the ITBS studies. BACK TO TEXT
- Bolgla LA, Malone TR, Uhl TL, Umberger BR. Hip and knee strength, EMG activity, and kinematics in subjects with patellofemoral pain syndrome. J Orthop Sports Phys Ther. 2006 Jan;36(1):A67. PubMed #18349475. ❐ PainSci #55989. ❐ A little more detail about their results: this research team studied a group of 20 women with patellofemoral pain syndrome, and 20 healthy people for comparison — but they emphasize that no causal relationship was established. And they found only “a moderate association” between pain and the strength of external rotation only, and a (still “moderate”) association with some increased EMG (electrical activity) in a key hip muscle, the gluteus medius, and the vastus medialis. Note that the researchers reported no difference at all in hip abduction (gluteus medius) strength, which is the exact muscle at the presumed center of the scientific controversy about hip strength and running injuries. The case for causation is virtually non-existent, and if a perfectly good little study can’t even find an association with gluteus medius strength … well, the whole thing is becoming really sketchy. BACK TO TEXT
- Ferber R, Kendall KD. Biomechanical approach to rehabilitation of lower extremity musculoskeletal injuries in runners. Unpublished. 2007 Jun. Ferber and Kendall studied “284 patients who visited his clinic complaining of leg pain” and found that “92 per cent had weak hip muscles.” They then “gave them a program to improve hip strength, along with other recommendations to speed their recovery.” They claim that the results were “astonishing” — a foolishly emotional word to use in science — with an alleged “89 per cent of the patients reported a significant improvement in pain within four to six weeks.” Exciting! And premature! BACK TO TEXT
- A Google search for “reed Ferber hip strengthening” turns up many media stories about this idea, and in major publications. An excellent example: in the September, 2009, issue of Runner’s World, Ferber’s theory is the basis of a short article, “All in the Hips” (p. 46). This time Ferber comments himself:
Inadequate hip muscle stabilization is a top cause of injury in runners.
That was a wild-eyed overstatement. Ferber did not actually have adequate evidence for that opinion. Yet he was clearly "promoting" it, without a sign of humility or caution, in the world’s most widely read running magazine, and many others.BACK TO TEXT
Another example: In December 2009, Running Times (no longer available online) uncritically reported on Ferber’s opinions, confidently declaring the precise alleged mechanisms by which hip weakness does its alleged dirty work — every bit of which is debatable, especially the part about pronation — saying definitely that “this is when misdiagnosis often occurs” (as if this isn’t an entirely unproven diagnosis itself), and concluding that “Ferber drives the point home.”
The Running Times article is particularly obnoxious because it heavily promotes ankle pronation as an evil consequence of hip weakness — pronation that Ferber himself denounced as poorly correlated with running injuries earlier in 2009. So not only does the article overconfidently promote an unproven explanation for running injuries, it promotes one that has actually been directly contradicted in print by the same scientist they are enthusiastically quoting!BACK TO TEXT
- Ferber R, Hreljac A, Kendall KD. Suspected Mechanisms in the Cause of Overuse Running Injuries: A Clinical Review. Sports Health: A Multidisciplinary Approach. 2009;1(3):242–246. PainSci #55475. ❐
The paper concludes that there is “a large and growing body of literature” backs up the idea that weak hips cause running injuries. Really? “Large?” Not even a dozen weak experiments, none of which clearly show cause and effect, is “large”? And the word “growing” is just a careless, informal exposure of bias: the only relevant thing to say is how much evidence actually exists now.
It’s ironic that this paper points out how correlations alone are not compelling with regards to the role of pronation in running injuries, but the same standard is not applied to the weak-hips evidence.BACK TO TEXT
- Ferber R, Noehren B, Hamill J, Davis IS. Competitive female runners with a history of iliotibial band syndrome demonstrate atypical hip and knee kinematics. J Orthop Sports Phys Ther. 2010 Feb;40(2):52–8. PubMed #20118523. ❐
This study is a fishing expedition to confirm the (pet) theory that hip strength is a significant factor in ITBS. It is not surprising in a general sense that it found some indications of abnormal running mechanics. What is notable is that the abnormalities do not correspond well or cleanly to the notion that “weak hips” are the problem. Also, typical of studies with results that aren’t that interesting, only the statistical significance of the abnormalities is mentioned, and not their actual size — which was probably small.BACK TO TEXT
- Ioannidis J. Why Most Published Research Findings Are False. PLoS Medicine. 2005 08;2(8):e124. PainSci #55463. ❐
This intensely intellectual paper — it’s completely, hopelessly nerdy — became one of the most downloaded articles in the history of the Public Library of Science and was described by the Boston Globe as an instant cult classic. Despite the title, the paper does not, in fact, say that “science is wrong,” but something much less sinister: that it should take rather a lot of good quality and convergent scientific evidence before we can be reasonably sure of something, and he presents good evidence that a lot of so-called conclusions are premature, not as “ready for prime time” as we would hope. This is not the least bit surprising to good scientists, who never claimed in the first place that their results are infallible or that their conclusions are “true.”
I go into much more detail here: Ioannidis: Making Medical Science Look Bad Since 2005.BACK TO TEXT
- Grau S, Krauss I, Maiwald C, Best R, Horstmann T. Hip abductor weakness is not the cause for iliotibial band syndrome. Int J Sports Med. 2008 Jul;29(7):579–83. PubMed #18050060. ❐ BACK TO TEXT
- Noehren B, Schmitz A, Hempel R, Westlake C, Black W. Assessment of strength, flexibility, and running mechanics in men with iliotibial band syndrome. J Orthop Sports Phys Ther. 2014 Mar;44(3):217–22. PubMed #24450366. ❐ PainSci #53183. ❐ BACK TO TEXT
- No one trains hip internal rotation. There’s no gym machine for it. You could go to a busy gym for an hour a day for a year and never see anyone working on this movement. That doesn’t mean it doesn’t matter, but it is jarringly at odds with what the hype on this topic was leading people to believe. Probably at least 80% of hip strengthening prescriptions inspired by the weak hips hypothesis are directed at abduction (moving the leg away from the midline), not rotation. And then along comes this study and says, “Actually, abduction strength seems to be fine in runners with ITBS … there might be a little difference in rotation strength.” Good grief. BACK TO TEXT
- Foch E, Reinbolt JA, Zhang S, Fitzhugh EC, Milner CE. Associations between iliotibial band injury status and running biomechanics in women. Gait Posture. 2015 Feb;41(2):706–10. PubMed #25701012. ❐ BACK TO TEXT
- Louw M, Deary C. The biomechanical variables involved in the aetiology of iliotibial band syndrome in distance runners - A systematic review of the literature. Phys Ther Sport. 2014 Feb;15(1):64–75. PubMed #23954385. ❐ BACK TO TEXT
- Brushøj C, Larsen K, Albrecht-Beste E, et al. Prevention of overuse injuries by a concurrent exercise program in subjects exposed to an increase in training load: a randomized controlled trial of 1020 army recruits. Am J Sports Med. 2008 Apr;36(4):663–670. PubMed #18337359. ❐ BACK TO TEXT