Why Do Women's Hips Sway When They Walk?

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Transcript

Regardless of culture, the sway of the hips is associated with beauty and femininity. If you look closely at the woman in the yellow dress, you’ll see that the when her right foot leads forward her right hip appears to rise and swing outward. As her right foot moves behind her, her right hip moves down and swings in slightly.

So why do women walk this way? It boils down to some key differences between male and female anatomy.

Male VS Female Pelvis

A key difference between the skeleton of men and women is the pelvic bone. The female pelvis tends to be wider and shorter than the male pelvis. It needs to be this way because women’s hips need accommodate something totally crazy: pregnancy.

The female pelvis needs to accommodate a baby that weighs 3.5 kilograms on average and be able to push the baby out during childbirth. In spite of being a doctor, I still can’t get over the fact that women literally have a human growing inside them for 9 months. It’s totally nuts.

Anyway, getting back to the point - because of the extra width of the pelvic bone, the hip joint is different in women as compared to men.

Male VS Female Hip Joint

The hip joint has two parts: the ball of the femur, which rotates within a socket in the pelvic bone, called the acetabulum.

If you look at the hip joint from above, you can see that the acetabulum in men is aligned straight across the ball of the femur, while the acetabulum in women tends to angle forward. This is called the acetabular anteversion angle, and women tend to have higher anteversion than men.

This means that in women, the pelvic bone needs to move along with the femur as women walk, as compared to men where the pelvic bone stays roughly in the same position while men walk.

Q-angle

Now looking from the front again, you will notice something different when it comes to the angle of the femur. In men the femur has a small angle moving in towards the centre of the body, but in women, the angle of the femur is much larger. This angle is called the Q-angle and on average, the Q angle is 4.6 degrees greater in women than in men. This doesn’t seem like a lot but it makes a big difference in how women walk.

In women, a combined result of a wider pelvis, greater anteversion of the acetabulum and higher Q-angle, means that the pelvis has to rotate in order to allow a woman to walk.

Combine this rotation in real time, and you get the classic hip sway of the female walk.

I hope this answered your question and satisfied your curiosity. Thanks for watching, and I’ll see you in the next one.

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References and Further Reading

Do Men and Women Walk Differently? (US Air Force Research Laboratory): https://apps.dtic.mil/dtic/tr/fulltext/u2/a597428.pdf

Q-angle: https://www.physio-pedia.com/%27Q%27_Angle

Gender differences in Hip Anatomy: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3217425/

Birth Weight: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2802014/

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Video credits

Certain illustrations adapted from https://www.svgrepo.com/ and https://www.freepik.com/ (Macrovector / Freepik)

Music:

Motionarray (affiliate link): https://motionarray.com?ref=ankitgupta1

Relax by Peyruis (https://soundcloud.com/peyruis). Creative Commons — Attribution 3.0 Unported — CC BY 3.0. Music promoted by Audio Library https://youtu.be/NvCDF7iUgIA

Fashion Show Footage: https://www.youtube.com/watch?v=jPUJUyC7K8U