Does Neutral Posture Matter?

Does Neutral Posture Matter?

Your posture should be like Switzerland, cheesy and neutral. Okay, maybe not cheesy, but definitely neutral. Or maybe not.

I’m sure you’ve heard this advice before: Keep the natural curves in your spine while performing daily activities, such as lifting, sitting, standing, and exercising.

But what is neutral? I answer that in this post.

First, we should ask “Does neutral actually matter? If so, why?”

Does Neutral Matter?

My first physical therapist told me I needed to flatten my lower back because I was too lordotic (pelvis tilted forward) and would get back pain if I didn’t correct the curve. My second physical therapist told me I needed to increase the curve of my lower back because I was too flat and would aggravate pelvic problems. Huh.

One personal trainer told me I needed to lift my chest; another physical therapist told me I needed to lower it. Double huh.

They all told me I needed to untwist my spine. Triple huh.

Even so, they agreed the goal was neutral alignment/posture. Most said if I didn’t correct my posture, I would be in pain. I wasn’t in pain. However, preemptively trying to correct my posture made me afraid to move, which, ironically, became a pain.

I started to wonder about the relationship between posture and pain. All the practitioners were so confident in their advice, but it all seemed so subtle and imprecise to me. How much does a non-neutral posture contribute to pain?

Extreme postural anomalies probably cause pain because of the load on tissues and joints, but natural minor variations in posture likely have little or no effect—at least according to several studies. Paul Ingraham, Todd Hargrove, and Cor-Kinectic do good jobs explaining the evidence, or lack thereof.

Their theses = Some posture habits probably influence pain, but not nearly as much as we think. Most people don’t have a “neutral” pelvis and most people aren’t in pain. We need to stop obsessing about the mythical static neutral.

What About the Pelvic Floor?

Fine. Pelvic tilt and pain seem unrelated. However, does posture affect your ability to activate the pelvic floor and, presumably, your abdominal muscles? Does it determine whether you will pee yourself, get pelvic organ prolapse, or close a diastasis recti?

These are hard questions to answer. I’m going to leave aside the diastasis recti question because I couldn’t find any concrete evidence to examine (for more, read The Alignment Cure). Fortunately, the pelvic floor question has been studied, although the conclusions are muddy.

Pelvic Posture and Muscle Activation

For example, a small study of 16 nulliparous continent women[1] looked at the affect of pelvic posture (tilt) on pelvic floor muscle activation. They found that the pelvic floor muscles activate more when the pelvis is in a “hypo-lordotic” tilt (a flat back) than when in a “hyper-lordotic” tilt (a swayback). However, “during the MVC, cough, Valsalva, and load-catching tasks, subjects generated significantly more PFM EMG activity when in their habitual posture than when in hyper- or hypo-lordotic postures.”

In other words, hypo or hyper lordotic postures may be inferior to plain ole’ natural tilts, presumably neutral. I honestly don’t know what clinical recommendations the findings support. The study was small and only looked at women who hadn’t pushed babies out of their vaginas. Nevertheless, we might conclude that we shouldn’t aim for hypo or hyper lordosis when doing anything that requires a strong activation of our pelvic floors, e.g. sneeze in neutral.

On the other hand, different research showed that pelvic floor muscle reactivity during voluntary contractions did not differ according to position[2] (this was for continent women) and that pelvic floor muscle timing during cough and “load-catching tasks” was unrelated to lumbopelvic posture. Though, baseline pelvic floor muscle activity did differ based on position, with the highest level in standing positions and the lowest in supine positions (because gravity and stuff).

Hmmm. So, what do we do with this information? I have no idea; maybe it simply means the pelvic floor works in lots of different positions (which is good since we aren’t paper dolls). I guess we could also conclude that a woman might fatigue a weakened pelvic floor if she spent her entire day standing, or conversely might fail to challenge her pelvic floor if she avoided standing enough.

What about prolapse?

As for prolapse and incontinence, some studies highlight a correlation between hypolordosis (flat backs) and prolapse, whereas others show no association. So which is it? Will spinal angle cause prolapse, or is it a non concern? How much does neutral matter? (Yes, I ask a lot of questions.)

Why Would Spinal Curvature Matter?

Let’s back up and figure out why researchers are measuring women’s spines in the first place. People don’t perform studies without a reason. Therefore, what is the rationale for thinking spinal curvature (a.k.a. posture) can influence pelvic floor disorder?

It comes down to intra-abdominal pressure and the ability of the pelvic floor to react against it. A couple decades ago, vector diagrams suggested that different spinal angles may cause different levels of pressure. If too much pressure falls onto the pelvic floor support structures (like ligaments and endopelvic fascia), they might give way and let the pelvic organs slide down, a seriously uncool situation.

It’s a good theory, so people wanted to test it. Unfortunately, it’s hard to test. So far, this testing is limited to measuring the spinal angles of women and then having them complete a questionnaire about their pelvic floor symptoms. These kinds of tests are retrospective, so pinpointing a causative, rather than a correlative relationship, is all but impossible. Nevertheless, if enough studies show a strong correlation between a particular spinal angle and pelvic floor symptoms, then theoretical evidence grows stronger.

What do the studies say?

This part is lengthy, but bear with me. Don’t worry, I promise to arrive at no definitive conclusion.

Kyphosis and Uterine Prolapse

A. A rather old study (1996) looked at the relationship between kyphosis and uterine prolapse by examining 48 women with advanced uterine prolapse and comparing them to 48 controls.[3] (Kyphosis is excessive upper back curvature, also known as hunchback.) They found that the women with uterine prolapse had a higher degree of kyphosis than those without it and concluded “thoracic kyphosis appears to be associated with uterine prolapse.”

This study had obvious limitations. One, it was retrospective.

Two, the findings would need to be replicated in a larger sample size to meaningfully mean much.

Three, as we all know, correlation does not equal causation. Even if a larger sample size confirmed the association, how do we know what caused it?

Despite its limitations, the degree of correlation does suggest posture and the pelvic floor might be related. We just don’t know why or how (two pretty important questions).

Lumbopelvic Tilt and Pelvic Organ Prolapse

B. Moving on: Another teeny tiny study, this one from 2000, compared the lumbopelvic tilt of women with and without pelvic organ prolapse.[4] 20 mothers without prolapse were matched with 20 mothers with prolapse, and their pelvic tilts were measured.

Their findings:

The mean lumbar lordotic angle in women with pelvic organ prolapse (32.0° ± 9.8°) was significantly lower than that of controls (42.4° ± 10.9°) (P <.003). The mean angle of the pelvic inlet in women with pelvic organ prolapse (37.5° ± 7.0°) was significantly larger than that of controls (29.5° ± 7.3°) (P <.001). The differences in the mean angles of lumbar lordosis and the pelvic inlet, between the case and control groups, remained significant after multivariable logistic regression was performed. Conclusion: Women with advanced uterovaginal prolapse have less lumbar lordosis and a pelvic inlet that is oriented less vertically than women without prolapse.

In plain English: The average of the lumbar lordotic angle of women with prolapse was smaller than the average of the angle in women without prolapse. Put another way, the women with prolapse had flatter lower backs.

This is interesting because that other small study said PFM activity was greater with a flat back than with a lordotic back, yet women with prolapse had flatter backs. Unfortunately, I couldn’t get my hands on the entire study. I’d be interested to know the range of angles. Were the prolapsed women clustered around a similar lordotic angle? Were they flattening their backs in response to prolapse, rather than the other way around?

Again, the numbers were so crazy small that drawing any conclusions is hard. Nevertheless, the degree differences between the groups were rather large. I’d like to know if anyone is doing a study that tries to predict the association between lumbar lordosis and the development of prolapse? This would be much more meaningful than comparing 40 women after the fact.

Yet, even without knowing the cause of the correlation, the study suggests a neutral pelvic tilt that allows for a more vertical pelvic inlet is a good thing.

Abnormal Spinal Curvature and Pelvic Organ Prolapse

C. Another study from 2000 also looked at the relationship between abnormal spinal curvature and pelvic organ prolapse.[5] They looked at the spinal curves of around 300 women who had complained about incontinence and/or prolapse and then used flexible rods to assess their spinal angles. The authors found that “only 11% of patients with stage 0 prolapse had an abnormal spinal curvature, which increased to 30% in patients with stage III prolapse.”

The authors rather boldly concluded that “an abnormal change in spinal curvature, specifically, a loss of lumbar lordosis, appears to be a significant risk factor in the development of pelvic organ prolapse.” I say “boldly” because they jumped to a causative association — i.e., spinal curvature is a risk factor for— rather than a correlative one — i.e., spinal curvature is associated with. Interestingly, they didn’t find any relationship between prolapse and the number of vaginal deliveries, the weight of the infants, or BMI.

D. A 2007 published in the Pakistan Journal of Biological Sciences also made bold statements about the relationship between spinal curvature and pelvic organ prolapse.[6] The researchers looked at 100 patients whom they deemed as having abnormally curved spines versus 100 controls. They found more evidence of prolapse among the patients with excessive kyphosis and loss of lumbar lordosis. Interesting.

But honestly, this study was hard to read. The researchers made sweeping generalizations about their findings and didn’t include much analysis of possible confounding factors.

They also explicitly hypothesized that normal spinal curvature is protective against intra-abdominal forces and that deviations in curves can exert high pressure on the pelvic tissue. Ummm…maybe, but their study didn’t actually investigate abdominal pressure, so I feel that conclusion was jumping way ahead.

Don’t get me wrong, the connection is compelling, just unfinished. What I take away: “Neutral” might be good for the pelvic floor.

A Systematic Review

E. Next up, we have a systematic review, one that examined the relationship between spinal curves and all health, not just the pelvic floor.[7] The researchers looked at studies before 2008. When browsing their notes, I realized they included the same studies I had found in Pubmed and had come to similar conclusions — that the studies were maddeningly inconclusive and tiny.

Fifty-four original studies were included [But only a handful related to pelvic floor issues and notably none related to diastasis recti]. We found no strong evidence for any association between sagittal spinal curves and any health outcomes including spinal pain. The included studies were generally of low methodological quality. There is moderate evidence for association between sagittal spinal curves and 4 health outcomes as follows: temporomandibular disorders (no odds ratios [ORs] provided), pelvic organ prolapse (OR, 3.18; 95% confidence interval [CI], 1.46–96.93), daily function (OR range, 1.8–3.7; 95% CI range, 1.1–6.3), and death (OR, 1.40; 95% CI, 1.08–1.91). These associations are however unlikely to be causal.

You may have noted, pelvic organ prolapse was one of the four categories for which there was moderate evidence of association, although the researchers said it probably wasn’t causal (There was also a moderate associate with death. Go figure). Still, moderate association is not no association and does warrant a look at your own posture if for no other reason than to cover your bases, so you don’t get prolapse and/or die. Kidding. I hope.

Pelvic Floor Symptoms and Spinal Angles

F. Last, let’s look at the largest and most recent study examining the pelvic floor and spinal angles. I spent a lot of time parsing “Pelvic Floor Symptoms and Spinal Curvature in Women,” mostly because the outcomes differed markedly from the previous studies.[8]

The authors were explicitly building off the research I’ve already talked about. They noted that we have a lot of data on the relationship between pelvic floor disorder and weak muscles; pelvic floor disorder and neuromuscular problems; and, pelvic floor disorder and damaged connective tissue. Basically, we know damage to the muscles, nerves, and connective tissue is strongly associated with prolapse and pelvic floor disorder. In contrast, evidence showing the association between “bony spinal curvature and PF symptoms have been lacking.” Hence, their study.

Although the relationship between spinal angle and pelvic floor disorder hasn’t been studied a lot, it has been studied a little, and those studies have clearly shown a relationship. Therefore, I was actually very surprised the authors found no relationship between pelvic floor symptoms and particular thoracic or lumbar spinal angles. None. Nada. It had no correlation.

Say what?

Like the other studies, they determined the presence of symptoms based on questionnaires, but unlike the other studies, they relied on radiographs or computed tomography exams (the woman were undergoing bone mineral density scans). The sample size was also much larger than that of previous studies and was more representative of the general population. Basically, this was a better study because of its size and technological access.

This isn’t to say it was a perfect study, no study is. The authors point out that retrospective questionnaires aren’t great and can lead to recall bias. Nonetheless, this study does not support a correlation between pelvic floor symptoms and spinal angle. That’s a pretty big deal considering that many clinicians think the relationship between posture and pelvic floor disorder is a foregone conclusion.

One study is never the final say, but it does put the other smaller studies in a different context. And it highlights a need to get some prospective studies that are not so limited by recall bias.

Why Care About the Research?

I did this esoteric search because I wanted to know why I had received such varying and conflicting advice. I realized, compared to the Kegel, posture evidence is murky and open to idiosyncratic interpretation.

Despite the 2016 study, I’m willing to concede that posture may affect some pelvic floor disorders. Unfortunately, we don’t know this for sure. Some hypotheses are better than others. I imagine excessive intra-abdominal pressure is not anyone’s friend. Maybe habitual spinal angles can influence this pressure.

However, neutral posture is not magic. And the evidence doesn’t support the idea that you are slated to pain or prolapse because of your “bad posture.”

Nonetheless, paying attention to our postures means paying attention to our bodies, which is a net good. Therefore, I have taken the time to notice and work on my own posture, while acknowledging that the evidence is not cut and dry. I notice how my pelvic floor feels and moves, or how my abdomen is stacked, but without worrying that small “imperfections” will condemn me to a life of pain or advanced prolapse.

The evidence just doesn’t support worrying too much about your spinal angle as a standalone intervention strategy. If we do focus on posture, it must be within a larger plan that includes efforts to increase strength (not the same as excess tension), to relax (not the same as overly weak), and to fine tune our coordination.

Many postnatal personal trainers take all the nuance out of the evidence base. I dislike overconfident predictions about what your posture will or will not cause.

This doesn’t mean abandoning all advice to find neutral. Again, I think this advice is still good. However, I call it “posture play,” not “prescription.” We don’t do women any favors if we fail to acknowledge the gray area.

A little humility goes a long way when working with female bodies.

So, does neutral posture matter? Maybe.


Endnotes:

  1. Angela Christine Capson, Joseph Nashed, Linda Mclean, “The role of lumbopelvic posture in pelvic floor muscle activation in continent women,” Journal of Electromyography and Kinesiology
    Volume 21, Issue 1, February 2011, Pages 166–177  ↩
  2. Daria Chmielewska, Magdalena Stania, et al., “Impact of Different Body Positions on Bioelectrical Activity of the Pelvic Floor Muscles in Nulliparous Continent Women,” BioMed Research International, February 2015.  ↩
  3. Lawrence R. Lind, Vincent Lucent, and Nina Kohn, “Thoracic kyphosis and the Prevalence of Advanced Uterine Prolapse,” Obstetrics and Gynecology, Volume 87, Issue 4, April 1996.  ↩
  4. ohn K. Nguyen, Lawrence R. Lind, Jeniifer Y. Choe, Francis McKindsey, Robert Sinow, and Narender N. Bhatia, “Lumbosacral spine and pelvic inlet changes associated with pelvic organ prolapse,” Obstetrics and Gynecology, Volume 95, Issue 3, 2000.  ↩
  5. Mattox TF, Lucente V, McIntyre P, et al. “Abnormal spinal curvature
    and its relationship to pelvic organ prolapse.” Am J Obstet Gynecol 2000; 183:1381–1384  ↩
  6. Manizheh Sayyah Melli and Mahasti Alizadeh, “Abnormal Spinal Curvature as a Risk Factor for Pelvic Organ Prolapse,” Pakistan Journal of Biological Sciences, 10 (23) 2007.  ↩
  7. ST Christensen and J. Hartvigsen, “Spinal curves and health: a systematic critical review of the epidemiological literature dealing with associations between sagittal spinal curves and health,” Journal of Manipulative and Physiological Therapeutics, Volume 31, Issue 9, 2008.  ↩
  8. Meyer I, McArthur TA, Tang Y, et. al., “Pelvic Floor Symptoms and Spinal Curvature in Women,” Female Pelvic Med Reconstr Surg. 2016 Apr 6.  ↩

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.