Manspreading — the act of sitting with your legs wide open, sometimes blocking off nearby seats on public transportation — has created such social annoyance that New York, Seattle and Madrid have created laws forbidding it. But in a recent interview, Stu McGill, a professor emeritus of Kinesiology (the study of body movements), explained that centuries of human evolution have made it so that some guys “manspread” out of a legitimate physical need rather than just selfishness.
It has to do with the fact that men have smaller pelvises than women. Women typically have wider pelvises to help with successful childbearing (whether they have kids or not). Men, in contrast have smaller more compact pelvises that allow for better walking and running. Wider pelvises give women more hip space for their leg bones to move around.
When some men sit with their legs closed, it can cause the head of the femur (the bone running through the thigh) to pinch the outer edge of the hip socket. This pinching can cause hip muscles to involuntarily tense up in search of a more comfortable position, creating strain on the hip and lower back. It can all become very uncomfortable very quickly.
With wider pelvises, women’s femurs do not pinch their hip sockets nearly as much when they sit with their legs closed.
Lou Schuler, the writer who spoke with Dr. McGill, doesn’t think that this biological explanation gives guys an excuse to be jerks on public transportation — “We all have to put up with a little discomfort to coexist,” he writes.
Rather, he shared this insight because online articles about manspreading seemed to treat it as purely a case of gendered privilege: Socially, guys are encouraged to take up space, whereas women are told to shrink and accommodate others. Since no articles talked about the physiological basis of manspreading, he wanted to share.
However, he concludes:
“With great manspreads come great responsibility. We don’t need to apologize for expanding to fill the available space. But when that space isn’t available, it’s on us to take one for the team and reel that shit in.”