“Mom Butt” is the term for a loss of ‘junk in the trunk,’ or a flat butt that tends to develop postpartum. Why does your bum go flat after pregnancy? Why do women’s bums seem to go flat after childbirth? What contributes to those weaker, less shapely glutes?
[Glutes, pronounced “gloots,” is short for ‘gluteals,’ the set of large muscles that make up the shape of your buttocks.]
Postural Changes and Inactivity
As the belly grows in weight and size, a pregnant person may tend to stand with an anterior pelvic tilt, stretching out the glute muscles in the rear. Some people also spend more time sitting/resting during pregnancy and for feedings postpartum, which also stretches the glute muscles and results in less time using them. Another common posture is the posterior pelvic tilt during holding/carrying the baby – jutting the pelvis forward and tucking the butt under. It’s a common postural shift to counterbalance holding the baby in front, but it’s not necessary and it results in weaker gluteal muscles. The end result of any of these postural changes if they become routine, is weaker and less shapely buttocks as the glutes spend less time in their role of maintaining erect posture. It’s a use-it-or-lose-it scenario.
View this post on Instagram
How to Optimize Posture for Butt Muscle Tone
Becoming aware of your posture can help to start changing the muscle strength and size of your buttocks. Take a look at your side profile in a mirror. Now look straight down at the floor in front of you. Shift until you can see the tops of your feet. Now STAY THERE as you bring your head back to neutral (looking forward). Check your side profile again. Your pelvis and low back positions should be more neutral. This cue to ‘see your feet’ often helps to shift from an extreme pelvic tilt into a more neutral position, with the ribcage stacked over the pelvis.
It may feel weird at first because your brain has to get used to the new position of your body. With repetition, it will feel natural. Now try this postural correction while holding/wearing your baby, while standing in line, etc. If it’s challenging or painful to maintain this posture, you will likely benefit from strengthening the glute muscles in order to develop the capacity and endurance to better support you. (Keep in mind that humans are meant to be mobile – frequently changing positions is recommended over staying in any one position for a really long time, no matter how “good” the posture is.)
View this post on Instagram
Exercises for Growing the Glutes
So how do you change the shape of Mom Butt? Strength training is key. “The Glute Guy” Bret Contreras, is my ultimate source for glute muscle training. He’s the world’s leading expert in gluteal muscle function and development, strength training, and program design. The benefits of gluteal strength are far beyond aesthetics. This also helps to avoid muscle strain, protect the knees from injury and pain, and provides joint stability for the hips, spine, and SI joints.
Glute strength helps a person to handle life’s daily tasks, as well as prevent and recover from injury. For the athlete, glute strength equates to improved sprinting, changing direction, throwing and striking, and heavy lifting. The exercise suggestions below are derived from the book Glute Lab – The Art and Science of Strength and Physique Training by Bret Contreras and Glen Cordoza. They are ‘glute-dominant’ exercises, meaning that there is constant tension on the gluteal muscles throughout the entire exercise, allowing maximum muscle contraction, metabolic stress, and blood flow constriction needed for muscle hypertrophy (growth).
The Influence of Genes and Jeans
A person’s butt shape and size is ultimately dependent on their genetics. You can manipulate your butt’s appearance by losing fat and adding muscle (and wearing a good pair of jeans), but you can’t change your skeletal anatomy. The size of your pelvic and hip bones (width of ilia, length and angle of femoral neck, distance between ilium and greater trochanter, size of greater trochanter, and sacral slope) all determine the shape of your buttocks, waist, and hips.
The skeletal anatomy also affects a person’s movement patterns and available motion; hence why one person can easily do narrow deep squats while the next requires legs wide apart. Anyone concerned about Mom Butt should be encouraged to focus on what you CAN change and on what feels good, and avoid fretting about your perfectly fine genetic variations. If you need individualized help, we’re available for in person sessions in New Orleans and virtual sessions from anywhere you choose!
Melissa Stendahl, PT is a pelvic health physical therapist with specialty certificates in the areas of prenatal and postpartum physical therapy. She has a unique approach with clients by promoting preventative care, active participation, education and understanding of their diagnosis and treatment plan so they feel empowered in their ability to achieve wellness. Melissa is a lifelong athlete, military veteran, and mom. She is the owner of Stendahl PT. Follow along on her Instagram.
Some links may be affiliates. This means we may make a small commission if you make a purchase. The products we recommend on this website and in blog posts are always products we use ourselves or recommend to clients. Thank you for supporting us in our mission to revolutionize women’s healthcare.