I have a twitter account and I’m not afraid to use it.
Last week I read this:
“@fitnessleak: study shows 3" high heels worn by women created stronger pelvic muscles lead 2 better sex @AlignedandWell what do u think?
For those of your who don’t know twitter-speak, this means “Hey, Katy, what do you think of what Fitnessleak wrote -- that a study shows that 3” heels worn by women created stronger pelvic muscles that lead to better sex.?
What do I think? What do I think? I think I want to put a hot poker in my eye.
This is not the first time someone has asked me my opinion about this article. I thought I’d answer it here, so you can all enjoy my answer 🙂
Once upon a time there was a high-heeled wearing urologist that stumbled across an article linking high heel use to schizophrenia (you should read the article, it is fascinating and just one more reason that I never wear anything with a positive heel!). This caused her great alarm as she loved her heels, even saying “although they are sometimes uncomfortable, I continue to wear them in an effort to appear more slender and taller.” Because she could not refute the article, she decided to prove a healthy aspect of heels.
She and her team created a study looking at changes in ankle positions that change pelvic tilt (that’s tucking or untucking your pelvis from a neutral position) and changes in pelvic floor activity. She measured this in 15 women. It is important to note that she did not have any of her subjects in shoes. That’s right. No shoes were worn by the people in the study. They just stood on wedges of different angles.
Here’s where it gets a little nerdy. She based her study on a previous study looking at the same thing: how does ankle position affect pelvic position and how does pelvic position affect pelvic floor contraction. I’ll call this the Chen study, after the lead researcher. The Chen study found that each ankle/pelvic angle brought about a different PF activity. They measured both resting and maximal (trying to squeeze it the tightest) force production.
The results? The greatest PF change came with DORSIflexion, which is the opposite of being on your toes.
Dorsiflexion looks like this:
All measured dorsiflexion angles had higher PF activity than plantarflexion.
Plantarflexion looks like this:
Dr. Highheel’s study also measured both resting and maximal contractions and here are her results:
What do you see, my little research students?
1. The greatest resting activity in the PF is, like the Chen study, higher with heels down, not heels up.
2. The maximal contraction (squeezing it hard) comes from 5° of plantar flexion (less than 1/2” of heel) not those ankle positions simulating 2 or 3" heels.
The conclusion of the study: Ten degrees of dorsiflexion (opposite of heels, remember?) might be just as effective as the 15° reported by Chen, but more comfortable. Low heels - not high heels.
How does one walk around in dorsiflexion? I don’t know. The researchers don’t know. It’s just a study, not a practical guide on how to use the information! And remember, they aren’t measuring walking - just standing on an angled board for a ten seconds in each position.
So how did we go from studies by Dr. Highheel and Dr. Chen, showing that dorsiflexion in the ankle gives greater resting PF readings than plantar flexion, to the headline
3” heels increase pelvic floor strength and better ooooh la la?
This is how: Dr. Highheel writes a letter to the editor to the Journal of European Urology called: Women Pay Attention to Shoe Heels: Besides Causing Schizophrenia They Might Affect Your Pelvic Floor Muscle Activity!!
(Catchy title, right?)
In this letter she says that she has done research (the research we just looked at) and that despite being linked to schizophrenia, heels might be beneficial as noted by her data. She fails to mention that dorsiflexion has been noted to have greater impact in the two conducted studies. Fails to mention that of the positive ankle positions measured, the 5-degree (the lowest) measurement of heel was "the best."
Boo. Bad scientist. Wanting heels to be healthy (as she stated she does) skewed how she presented the material to the public. That's a huge (HUGE!) no-no.
Of course, the media picked up on her letter to the editor and didn’t follow up with reading the research portion.
No shoes were used in the study. High heels (or any heels) were never measured.
Negative ankle position measured greater PF activity than positive ankle positions, not the other way around.
And, I have a bigger issue with both the Chen and the Cerruto (Dr. Highheel) studies.
How is pelvic floor contraction measured? With EMG (electromyography). An electrode picks up on the quantity of electricity flowing through an muscle and converts it to forces the muscle generated. Ideally, EMG is measured by an electrode placed into the measured muscle with a tiny needle. But not many people want a needle jammed in their pelvic floor, myself included. So researchers (and therapists) use a patch that reads electricity around the area of a muscle, through the skin.
The problem with this method is that the patch picks up every other muscle contraction in the area as well. It's called cross-talk. And what is the nice neighbor of the PF? The lower glutes. These are the muscles you use when you’ve had 5 cups of coffee, 3 bran muffins and are sitting in traffic. They are also the muscles that you use to tuck the pelvis under. Go ahead and try it. Pretend your bowels are going to explode and you’ll feel those low low glutes squeeze your cheeks together.
Any change in ankle position, up or down, causes the pelvis to tilt from neutral, which causes the low glutes to fire. This means your PF data is automatically tainted (hee hee) with glute cross-talk. Dear researchers: You’re not even measuring what you think you are. You’re not isolating the variable!
Muscle geometry and biomechanical science demonstrates that neutral pelvis will give you the optimal pelvic strength (not too much tension and not too little) every time. Any heel, high or low causes your pelvis to tilt from neutral. I’m not a fan of walking around with my toes higher than my heels, or my heels higher than my toes. I like to be more grounded than that. Think flats or minimal footwear. But if you love LOVE shoes, go with Earth Kalso bottom. The negative is at least a little better than the positive.
And, take note on what you read. The story - High Heels Increase Pelvic Floor Strength was reported in just about every prominent health magazine, newspaper, and television network. No one bothered to check the research.
When I moved about 3 weeks ago I finally chucked my last pair of heeled shoes. Note the cobwebs...
Schizophrenia? Really? What more do you need to hear? I commented on another doctor's poor advice in last week's LA Times (Posh Spice, her bad back, and her high heels: http://www.latimes.com/health/boostershots/la-heb-victoria-beckham-slipped-disc-20110823,0,4494319.story. And I do a whole lot more high-heel/bad advice commenting in my new book coming out later this year, Every Woman's Guide to Foot Pain: The New Science of Healthy Feet!
C.H. Chen, M.H. Huang, T.W. Chen, et al.. Relationship between ankle position and pelvic floor muscle activity in female stress urinary incontinence. Urology 66 (2005) (288 - 292)
M.A. Cerruto, E. Vedovi, S. Dalla Riva, et al.. The effect of ankle inclination in upright position on the electromyographic activity of pelvic floor muscles in women with stress urinary incontinence. Eur Urol Suppl 6 (2007) (102)
Flensmark. Is there an association between the use of heeled footwear and schizophrenia?. Med Hypotheses 63 (2004) (740 - 747)
Women Pay Attention to Shoe Heels: Besides Causing Schizophrenia They Might Affect Your Pelvic Floor Muscle Activity!! Maria Angela Cerruto, Ermes Vedovi, William Mantovani. Accepted 15 January 2008, Published online 24 January 2008, pages 1094 - 1095
Surface EMG crosstalk evaluated from experimental recordings and simulated signals. Reflections on crosstalk interpretation, quantification and reduction. Farina, D. Merletti, R. Indino, B. Graven-Nielsen, T. Dipartimento di Elettronica, Politecnico di Torino, Corso Duca degli Abruzzi 24, Torino, 10129, Italy.