The Junkless Trunk: And Not in A Good Way

I get my sweat on twice a week with a park workout that I love – brisk walking, plyometrics and strengthening. Just me, the dog, a resistance tube, birds chirping, flowers blooming, sun shining and (cue nails scratching a chalkboard) the local stroller fitness class. How could a group of women with nothing but the best intentions disrupt my perfect scene?

Their exercise form sucks. There I said it.

The trainer pushes them on to sprinting with bad form, doing crunches with bad form, lunges, push-ups, planks, hills….all with the same bad form. They all have their bums tucked under, creating a flattened junkless trunk. Rehab pro’s would call this a posterior pelvic tilt. It’s the position most women find themselves in as their pregnancy progresses. The pelvis often rocks under to balance and make room for the added baby and abdomen out front. They get stuck in that bum tucked under position post-partum because their muscles change length and weaken keeping the pelvis tipped. The posture is reinforced over the years by daily sitting in a slump, standing and walking with bums tucked…and horror of horror exercising that way.

You might ask…”but isn’t it good to sort of tuck your bum to you know…make it disappear?” Or “My mother (or insert other primary influence here: trainer, PT, Jane Fonda, pamphlet at the doctors office, etc) told me to tuck under for better form and/or posture. What gives?”. This exercise norm of days past is now a no-no. Just as full sit-ups gave way to crunches, and now crunches are moving aside for planks, research is evolving.

Join the evolution! Here are five reasons not to tuck your bum during exercise (or ever):

1. A tucked under bum reduces the availabilty of the pelvic floor. Studies have shown us that  the pelvic floor is less active when bums are tucked when compared to postural alignment that is untucked (Neutral pelvic tilt).  The result: a less active pelvic floor while exercising may contribute to leaks with exertion and can contribute to hip and back aches during exercise.

2. If you run with bum tucked under, it keeps the “engine” for your run, forward in your quads. The result: a running style that is quad dominant. This results in an up/down bouncy cadence creating high impact as each foot hits the ground. The added impact of running up and down and the lack of balanced muscle action around the joints can lead to knee and foot pain and contribute to leaks.

3. A tucked under bum running posture and quad dominance, also means you cannot stride out behind you and use the glutes to power walking/running. The result: No glute support for hips and backs during running. When gluteus maximus engages,there is an upward lift of the pelvic floor. So no glutes also means no pelvic floor. No g(l)utes, no glory.

4. Bum tucked under is the most open position of the SI joint; where the pelvis connects to the spine. The result: A sustained bum tucked under position leaves this joint susceptible to irritation, particularly with impact activities including walking, running, jump rope, or simply stepping off a curb wrong. Combine a more vulnerable position of the SI with reduced pelvic floor activity (#1) and you have a recipe for low back vulnerability.

5. When you tuck your bum, you also flatten your low back. The result: a loss of the shock absorption capacity of the curves in the spine. When the low back curve disappears the discs and joints are susceptible to the wear and tear of repeat impact.

So how do you know if this is you? Here is your junkless trunk checklist:

  • Can you fill your jeans up in the rear like you used to?
  • When you squat down do you get that underwear revealing gap between your waistband and low back (it’s not just the cut of the jeans ladies)
  • Do you have low back, hip, knee or SI pain that gets worse with exercise?
  • Do you leak while you exercise?

Sound familiar??

before after
Tucked – No Junk Untucked – Full on Junk

Time to untuck that bum!  A visual image often used to enhance posture is of a string that pulls us up through the top of the head to help us get into the right alignment. Instead imagine the string is tied to the top of your bum. Pull it gently to the sky, recreating a soft curve in your low back. This promotes what is called a neutral pelvic position which is the optimum alignment for pelvic floor and gluteal function. Sitting, standing, and exercising with a neutral tilt will reduce your vulnerability to injury and promote a better result from your fitness program. And best of all-your “trunk” will look great in those jeans again!

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14 thoughts on “The Junkless Trunk: And Not in A Good Way”

  1. Meredith says:

    Awesome post (found the link through aligned and well). I had been puzzling over why I got a really big DR after having my first baby. I thought it was because she was so big, almost 10 pounds, and I’m so not big, but other people were telling me big babies don’t actually cause a DR, but I know I didn’t have one before getting pregnant, yet it didn’t go away after pregnancy either, so I was stumped. What your post pointed out is that pregnancy can affect the way we hold our pelvis, likely making worse already bad habits, but also creating new bad habits. I’m 8 months pregnant again with another huge baby and only after reading this post have I noticed that yes I am pushing my pelvis forward as a way to compensate for my large belly. So now I realize pregnancy isn’t the sole cause of a DR, but rather how you hold your body during pregnancy and after is the culprit. Such a small thing to learn, but this was sooo not obvious to me.

  2. T says:


    Mi spine has a weird curvature on the lower back part naturally giving me that “tucked” position since I was little. And “untucking” it actually makes it painful. Keeping this in mind, which posture should I use?



    1. Julie Wiebe says:

      Visualizing your curvature would help me respond more accurately. A scoliosis could be compensated for by tucking under. Or you are one of those folks that came to earth already tucked under, plus have a scoliosis. In my book most folks are either tucked under from birth or tuck under as a compensation. Not being able to untuck without pain could mean that you are structured with a more tucked under bum or that the scoliosis is creating a torque thru your low back as you try to create some extension in your spine with a pelvic change. In either case, my goal is to GRADUALLY work folks toward neutral as best they can. But in your case, I might try to alter your alignment thru other means-adjusting rib cage position (I give some hints here ), or thru your feet. The rib cage misalignment and misuse that is common with spine curvatures would actually be my first concern for you, retraining your diaphragm in an improved alignment would be my first choice for you over altering the pelvis, particularly if it is painful. (I give some hints here ). I actually like to call the alignment I am gunning for the Piston Posture b.c it accesses the piston like action and support of the Diaphragm and Pelvic floor for alignment changes.

      Hope that helps! Let me know if you have any other questions! Take care! Julie

  3. Julie Wiebe says:

    The simplest insight is often the best! Glad for your ah-ha. Alignment is critical to reducing vulnerability to a large Diastasis Recti (DR) during pregnancy, and essential for promoting closure after delivery. I think of the a DR as an open zipper in your abdomen. If you have an open fly and you tuck your bum under it will cause the fly to gape wide open (faux pas! ). Same thing goes for your DR, it will gape open ALL DAY if you keep the bum tucked under. Your rib cage has likely slid backward as well (you can see the position shift of my upper back shift in the picture as well). This will also gape your DR open fly ALL DAY! No amount of diastasis exercises will correct an imbalance that is being reinforced ALL DAY in your alignment.

    Be aware, the linea alba connective tissue that separates in pregnancy creating the DR is designed to do that. I think of it as a safety valve for the growth of the baby in torso’s that are too short for large babies, trying to carry twins, etc. Lots of women separate, their alignment can make them more vulnerable to it , so can pregnancy fitness choices like crunches . But for many of those women the DR will resolve with good alignment and good post partum fitness choices (like no crunches….please note theme!!). But for some the DR lingers, and they will need extra help to assist with closure. Attending to your alignment is a great first step!

    Thanks for writing! Julie

  4. T says:

    Thanks you so much for your response! I will make sure to read the links you gave me 🙂
    Due to my line of work, I’m lifting children all day long and it is starting to be a strain on my back.
    I was also recommended to try yoga to better align myself and I found a place whose owner says that she had the same back issue and that she should be able to help me.
    Thanks again for everything!

    1. Julie Wiebe says:

      I hope you find the help you need! As a litmus test for my patients to determine if they are benefitting from and not being harmed by a particular yoga pose (or any exercise for that matter) I ask them to be sure they can hold their alignment and pull it off without holding their breath. If you find that you have to hold your breath to pull off what the teacher is asking you to do, then the exercise is either too hard or you can’t access your inner core well enough yet to support it.(I like to call the inner core the anticipatory core, more here: ).

      All the best! Let me know if you have any other questions. Julie

  5. Meredith says:

    Thanks for responding. Yes, I had heard the no crunches thing, but only after doing them for a couple weeks post-baby. After learning not to crunch, I had been doing some Tupler exercises, which I think don’t hurt, but at the same time not noticing my own alignment or how I tucked my pelvis meant those exercises probably weren’t even helping much. I’m not ruling out the option of surgery as a very very last resort some day since my DR is quite big (but of course I absolutely do not want to go that route if I can help it), but surgery is not a good fix for anything if you continue the same bad habits or keep yourself gaped with the same bad alignment. I find it pretty amazing that none of my midwives or exercise books ever address how you are holding your body and how this can affect the DR (or for that matter, my midwives didn’t even tell me about a DR and absolutely everyone to whom I mentioned it had no idea what I was talking about…including the trainers at the gym I joined temporarily). I’m hoping my recovery will be helped along after this baby by knowledge of how I should hold my body, even if getting it right is pretty difficult for me right now (I’m constantly asking my husband to evaluate my “posture” and he thinks I’m crazy).

    1. Julie Wiebe says:

      I am glad you have some new tools to help you thru this pregnancy and prep for recovery! You aren’t crazy, you are trying to replace an old habit, which takes vigilance and you would benefit from specific exercises to support the posture we are gunning for. I recommended a few of my other blogs in a previous response, check them out for more hints on what you can be doing internally ( and ). As for the more external muscles that can help support the alignment, so you and your husband don’t have to work so hard, think about working your lats and gluts together (a video blog is on the to-do list). WHere are you geographically, I will cross my fingers that I could refer you to someone local that has taken my course (I teach a whole system to help with the issues your are experiencing).

      Also, I try to abide by the ‘if you don’t have anything nice to say’ adage, but I am going to come clean here and say I really strongly disagree with the Tupler Technique. The exercises are encouraged in sitting, which most women slouch into and keep very poor alignment. And sitting and performing a mini-crunch will likely encourage breath holding and create a ton of pressure from above directly on a weakened pelvic floors. Not good.

      All the best and let me know where you are! Julie

  6. Danielle says:

    Hi Julie,
    I am a Pilates teacher with a lot of pregnant clients and I’m looking for safe effective exercises to teach them. I love your videos! I just finished watching some of the Pelvic floor webinar. My question is this: You wrote that often pregnancy puts the pelvis into a posterior tilt (tuck) in pregnancy, and this is how many women wind up with a junkless trunk. However I read elsewhere that often pregnancy forces an anterior pelvic tilt because of the weight of the belly in front, and that this is why the hamstrings often feel tight (because they are already being stretched by the ischial tuberosities being lifted from the tilt.) And the low back often becomes crunched. I myself had 2 pregnancies and felt very much a forward tilt. (And still do feel like I have that). I also am a chest breather, have an umbilical hernia and a slight DR. Are both possible? Just curious because you didn’t mention anterior tilt at all. I’m wondering for myself and my clients. Thanks!!!

    1. Julie Wiebe says:

      Hi Danielle,

      This is a great question and I am glad you asked it. We have described alignment for far too long based on the lumbo-pelvic position only. I am on a mission to get folks to consider the position of the ribcage when assessing alignment bc the position of the ribcage can trick your eye. Many, many pregnant ladies translate that ribcage behind them to get it out of the way of the growing belly. The pelvis reacts to this (and vice versa). This is a great article about that interrelationship here: Pregnant ladies have tricked our eyes for years in the same way. There is a very big assumption out there that most pregnant and post partum women are Anterior Tilters (AT’ers). However, I disagree bc we have not taken into account the position of the ribcage. This is one of my soap boxes, and supported here where 11/15 pregnant women in this study were in a posterior pelvic position:

      I didn’t help by only focusing on the pelvic position in the blog. But let’s rectify that. Take a second look at the pictures. If you hadn’t read the blog and only looked at the pictures, at first glance you might say I am standing in an anterior tilt and lots of lordosis in the “Tucked, No Junk” picture. Show it to a pro near you without a caption or the text and see what they say. My elbow is blocking my lordosis so it is hard to see where I actually kink in the back or curve, but it is higher up closer to my t-spine, not a true hyperlordosis that is usually associated with anterior tilt. It is that position of my upper body, my rib cage, relative to the pelvis that is tricking your eye. My pelvis is actually tucked. I hope you can see that, especially as you contrast it to the “Full on Junk” picture. In that picture not only is the pelvis untucked but the ribs are in a right relationship over top of the pelvis.

      I am not sure how far along you are in the pelvic floor webinar (, but I get into the position of the rib cage relative to the pelvis as a better definition or better understanding of alignment as you get further into the material. Primarily bc this is what optimizes the relationship between the diaphragm and pelvic floor which is the foundation of our central stability. There are more cues there too on how to alter alignment both at the rib cage and pelvis in a more passive way vs holding yourself in “good” alignment and disrupting muscular balance.

      There are anterior tilters out there. But a STRONG majority of women are tucked without realizing it. There’s a test for that in the webinar too :)! This is not just bc of pregnancy our lifestyle is so sedentary now, and only interrupted by fitness vs years ago when life’s basics took more physical work interrupted by sitting for meals. Sitting a ton is a great way to keep your bum tucked. So I focus on the bum tuckers bc it needs more press :)!

      Hope that helps! Julie

  7. This is such amazing knowledge and solidifies my disdain for bad form while working out. I am looking so forward to learning more from you in Chicago soon, Julie! I am going to help spread your message to mamas!

    1. Julie Wiebe says:

      YAY Suzanne! Thanks for weighing in and I so look forward to seeing you in Chicago, it’s going to be a great class! Working on the handouts as we speak! Julie

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