At a Glance
- The study identified that body shapes with curved “hips” and a “waist” shape are crucial for maintaining a hula hoop’s motion, explaining why some people excel at hula hooping while others struggle.
- Researchers used 3D-printed miniature models with different body shapes and motor-driven motions to analyze the physics of hula hooping, revealing the importance of body shape over motion alone.
- A sloped surface, like hips, helps push the hoop upward, while a curvy waist stabilizes it, ensuring the hoop remains suspended against gravity.
- The mathematical models developed could inform advancements in robotics, energy harvesting from vibrations, and the efficiency of industrial machinery.
- The research showcases how understanding the mechanics of everyday activities, like hula hooping, can inspire technological innovations and applications beyond recreational use.
A new study from the University of Liverpool has finally explained the physics behind hula hooping, uncovering why some people are natural hoopers while others struggle. Researchers studied the mechanics of the hula hoop using robotic models with different body shapes to determine how the hoop stays suspended against gravity. The study, published in Proceedings of the National Academy of Sciences, shows that certain body types with curved “hips” and a “waist” shape are key to keeping the hoop up.
The research team, led by Leif Ristroph from New York University, used miniature models with 3D-printed body shapes—ranging from cylinders to hourglass forms—to replicate hula-hooping motions. Motors set these models into motion to mimic humans’ gyrating movements when hula-hooping. High-speed cameras captured the results, showing that the motion itself wasn’t the issue; instead, the body’s shape played a crucial role in keeping the hoop elevated.
The study found that to keep a hula hoop up for an extended time, a body needs a sloped surface, like “hips,” to push the hoop upward and a curvy “waist” to stabilize it. This explains why some people naturally excel at hula hooping while others must work harder to maintain the hoop’s motion. “Our results suggest that certain body shapes are better suited to hula hooping, which could be why some people find it easier than others,” said Ristroph.
This research enhances our understanding of hula hooping and has practical applications. The mathematical models developed by the team could inform new ways to control mechanical systems in robotics, help harvest energy from vibrations, and even improve the efficiency of industrial machinery. As Ristroph pointed out, “The math behind hula hooping has much broader implications, from energy harvesting to robotics.” The study opens up new possibilities for technology inspired by the mechanics of this fun and familiar activity.
References
- Zhu, X., Pomerenk, O., & Ristroph, L. (2025). Geometrically modulated contact forces enable hula hoop levitation. Proceedings of the National Academy of Sciences, 122(1), e2411588121. https://doi.org/10.1073/pnas.2411588121
- New York University. (2025, January 2). How does a hula hoop master gravity? Mathematicians prove that body shape matters. Phys.Org; New York University. https://phys.org/news/2025-01-hula-hoop-master-gravity-mathematicians.html
