To Tuck or Not to Tuck: Why always tucking the pelvis isn’t the best strategy for movement freedom
I will never forgot the first time I worked with someone who habitually tucked her pelvis. She was referred to me by an acupuncturist who was hopeful I could help her with the chronic low back pain she was experiencing. As soon as she walked in, I could tell her gait was stiff. As I watched her move, her pelvis remained tucked in every position. She explained she had done quite a bit of a specific movement modality that cued pelvis tucking in a lot of the exercises, so she made a conscious effort to tuck in order to keep her back stable.
Your pelvis, the hollow bowl-like structure that connects to the spine and the lower extremity (specifically, your leg), is designed to move a variety of ways (1). Using the top of the pelvis as a reference point, you can tip the top of the pelvis forward. This would move the bottom of the pelvis back. (You can try this right now by coming into a tall kneeling position with your fingers on your two front pelvis bones where your pants normally sit. What happens to the bottom of the pelvis when you do this? Hopefully, it moves back. Otherwise, you have successfully invented a new dance move.)
When you perform the above movement, you are moving your pelvis anteriorly. Now, come into the same position, but move the two front pelvis bones away from your fingers. What happens to the bottom of the pelvis? It moves forward, right? This is tilting your pelvis posteriorly, aka as tucking your pelvis.
Go back and forth between the two positions a few times, bringing your pelvis bones forward into your fingers and back, away from your fingers. Once you’ve done six or eight, settle into a comfortable position. How does that feel?
Different movements require the pelvis to tilt one way or the other. In fact, certain movements coordinate with an anterior pelvic tilt and others coordinate with a posterior pelvic tilt. We have the ability for our pelvis to move both ways for a reason. What becomes problematic is when the pelvis becomes habitually held in one position.
The anatomy of the tuck:
What happens when you tuck your pelvis? Since the back wall of the pelvis is made up of the sacrum, which happens to be the five fused vertebrae that form the segment of the spine following the lumbar vertebrae, when you move your pelvis either forward or back, there will be echos of the movement throughout the base of the spine, meaning the lowest lumbar vertebrae will move into a little bit of flexion if you’re tucked, or extension if you’re in an anterior tilt. The lumbosacral joint is the meeting place of the lumbar spine and the sacrum. It’s designed to allow pelvic rotation during walking (2). If the pelvis is always tucked and what do you think that does to the rest of the spine when you walk?
It will limit movement, making your gait less efficient. Try this: sit long on the floor with your legs extended in front of you (if you can’t extend your legs long, you can do this with your legs bent). Roll in front of your sitting bones (the knobby bones at the bottom of the pelvis), and behind your sitting bones. Do this three or four times. Pause behind your sitting bones. This is the “tucked” position.
Try and walk your pelvis forward in the tucked position. How does that feel? Do you move very much?
Now, roll your pelvis forward and back a few more times and stop with yourself on your sitting bones or just in front of your sitting bones. Walk forward again. How does that feel?
(I tried this. I’m not winning any pelvis walking races in the tucked position: https://www.instagram.com/p/BvRSPdtB-hu/).
Probably a lot easier, right? That’s because your pelvis has room to rotate when it’s not tucked under; rotation is a motion that’s necessary for walking. If your pelvis doesn’t rotate, you will pick up the rotation from somewhere else so that you can propel yourself forward.
How much rotation/flexion/extension are you “supposed” to have, you may be wondering? It turns out, everyone is a little bit different, and how much your pelvis moves when you walk depends on things like whether you’re male or female and how old you are (3). There is no “gold standard” for how much a joint moves. What matters more is the sense of freedom you feel in the area.
The belly situation:
There are a number of muscles that attach to the pelvis, both from the torso/abdominal/back region and the hip region. If you habitually tuck your pelvis under, it’s going to impact how you feel work in your abdominals and how you feel work in your hips.
“But wait,” those of you who study movement might be thinking, “aren’t the abdominals the muscles used to tuck the pelvis? So if my pelvis is constantly tucked, I should feel work in my abdominals always, right?”
Yes, the rectus abdominis, your six pack muscles, attaches at the pelvis and plays a role in posteriorly tilting the spine (4). BUT (and this is a big but), in a standing position, your body will default to the position that requires the least amount of effort. If your tendency is to place your pelvis under your body, your weight in the center of the body is suddenly going forward. To counterbalance, you may adopt a number of strategies, not all of which place a large amount of load in the abdominals. In fact, one of the things I find most interesting about chronic tuckers is usually when I have them move their hips back in standing (which conveniently untucks the pelvis), they all comment on how much they suddenly feel their abdominals working.
If you are habitually tensing your abdominals to maintain a pelvic tilt, you are working your abdominals just not in a way that’s working for you. Muscles work best on the joints they move when they have the ability to move through a broad range of motion with the appropriate amount of tension required for the task. Do I need the same amount of abdominal tension to lay here and write this as I do to deadlift a heavy, wet log? Probably not. The neuromuscular system likes options with all things; muscle tone is no exception.
Research suggests that when you contract the pelvic floor muscles voluntarily, you also contract the abdominals (5). If you have a tendency to suck in your belly or you really try to keep your abs flexed because you feel like you “look” better this way, you may be doing your pelvic floor a disservice. Not only are you limiting movement at the spine and pelvis, if contracting your pelvic floor results in abdominal contraction, maybe contracting your abs causes a change in pelvic floor contraction. Creating tension in a variety of positions is important, but so is the ability to let the tension go. Does your dog have to suck in its belly to maintain stability? You didn’t evolve to suck in your gut or stay tense all of the time. Movement freedom is determined by tension AND ease.
What about the hips?
There are lots of muscles that attach on the outside of the pelvis. Many of them control rotation and movement at the hip joint.
What does this mean if you are habitually in a tucked position? Your hip mobility will be reduced and your poor femur will struggle to move freely in the joint.
You can feel this when you stand. As soon as you tuck your pelvis, your pelvis shifts forward and your weight in your feet shifts back. When you lift your leg in this position, it requires effort because your torso and hip are far away from each other. If you untuck your pelvis, your torso shifts forward and you are able to lift your leg much easier. (I totally just tried this for the first time. It was much harder than I expected. Now I see why my tucked clients all flex their hips by posteriorly tilting their pelvises! Lightbulb moment.)
None of this is good for the health of the hips. Joints thrive on working through a a full range of motion in the socket. When the range of motion is reduced because of a habitual holding pattern, the lack of movement in the joint can lead to sensations of discomfort.
Holding the pelvis so it stays in one position, all of the time, is disadvantageous for movement; it’s also disadvantageous for things like pelvic floor health.
Your pelvic floor is comprised of bone, muscles, and connective tissue (6). These muscles contract and relax throughout the day when you do things like breathe, go to the bathroom or have sexual intercourse.
When you breathe, your inhale moves the diaphragm down and the pelvic floor muscles relax. On your exhale, the pelvic floor contracts. The abdominal muscles, including the diaphragm, and the pelvic floor muscles work together to maintain pressure in the abdominal cavity (7). This is known as IAP and plays an important role in creating a sense of stability in the torso when you lift a heavy object or when you cough (I know, two seemingly unrelated things, but both cause force that needs to be dealt with. IAP is what nature came up with to keep the organs safe).
The muscles of the pelvic floor are designed to contract and relax. I mentioned earlier habitually holding in your stomach affects the pelvic floor muscles by contracting them, but what happens if you habitually tuck your pelvis and you aren’t sucking in your abs to do it? Would that affect your pelvic floor muscles?
Imagine you lived most of your time with your arms bent, holding a five pound medicine ball. Your arms stay in that position for sixteen hours a day, except when you eat and go to the bathroom. Let’s pretend you stayed in this position for five years. How easy would it be to straighten your arms at the end of that five years?
Hard, right? In fact, you probably wouldn’t have the strength to straighten your arms, let alone reach for anything behind you. Whenever you keep a joint locked in one position, the muscles that move the joint in different directions become weak even though they are strong in the one position they spend most of their time in.
What if instead of holding a five pound ball, you rested your elbows on a table for sixteen hours a day for the next five years? Not only would you have extreme difficulty straightening the elbows, you wouldn’t have strength to hold anything with your elbows bent, either. The muscles that support the joint can not only be stiff, but can also be weak, depending upon how you’ve been using your body. If you remain habitually tucked, the muscles in your pelvic floor won’t have strength throughout their full range of motion. If you’ve been holding the pelvis in one position with a lot of muscular effort, these muscles may be unable to relax; if you’ve been holding them with minimal muscular effort, they may be unable to contract. Either way, restoring mobility to the pelvis will improve overall function and health of the pelvic floor.
I created two videos to help you free your pelvis and reduce low back pain using these concepts.
There are other things that affect your pelvis and how the muscles in the pelvic floor are contracting, like where you place the weight in your feet. Changing the foot position has been shown to change pelvic floor muscle activity. It’s all connected, so if you have postural habits, just know it will affect the rest of you in some way (8).
So, should you tuck? You should certainly have the ability to tuck when the movement or condition calls for it, but holding yourself in one way, all of the time, reduces your options, as well as your strength and mobility. If you habitually tuck, ask yourself why? Often, postural tendencies arise because we’ve been told that’s the way we “should” move. Your pelvis is designed to move a variety of ways and should feel free when you walk, not stiff.
Another reason people develop habitual postural tendencies is because their systems, either consciously or unconsciously, don’t have the knowledge or ability to be in another position. This can happens for a variety of reasons, including a sense of weakness in a specific area or because there has been a trauma causing a loss of connection with the area. Free your pelvis and improve awareness through gentle, somatic movements and get strong in a variety of positions to feel more resilient. You deserve to feel—and use—all of the parts of you.
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References:
Wobser, A.M., & Wobser, R.W., (2018). Anatomy, abdomen and pelvis, bones (ilium, ischium, and pubis). StatPearls. https://www.ncbi.nlm.nih.gov/books/NBK519524/ *This is really good. If you are interested in the anatomy of the pelvis, worth a read.
Muscolino, J., (2017). Kinesiology—E-Book: The Skeletal System and Muscle Function. https://books.google.com/books
Palastanga, N., Field, D., & Soames, R., (2006). Anatomy and Human Movement: Structure and Function, Volume 20056. Elsevier Health Sciences: New York.
Lee, S-Y., (2015). Muscle activation of the rectus abdominis and rectus femoris and their ratio during leg raises performed by healthy adults. Journal of Physical Therapy Science, 27(3), 549-550.
Madill, S.J., & McLean, L., (2008). Quantification of abdominal and pelvic floor muscle synergies in response to pelvic floor contractions. Journal of Electromyography & Kinesiology, 18(6), 955-964.
Faublon, S.S., Shuster, L.T., & Bharucha, A.E., (2012). Recognition and management of non relaxing pelvic floor dysfunction. Mayo Clinic Proceedings, 87(2), 187-193.
Park, H., & Han, D., (2015). The effect of the correlation between the contraction of the pelvic floor muscles and diaphragmatic motion during breathing. Journal of Physical Therapy, 27(7), 2113-2115.
Halski, T., Slupska, L., Dymarek, R., Bartnicki, J., Halska, U., Krol, A., Paprocka-Borowicz, M., Dembowski, J., Zdrojowy, R., & Ptaszkowski, K., (2014). Evaluation of bioelectrical activity of pelvic floor muscles and synergistic muscles depending on orientation of pelvis in menopausal women with symptoms of stress urinary incontinence: a preliminary observational study. Biomedical Research International.