A school uniform has an almost unremarkable quality. The black shoes, the pleated skirt, and the white shirt. On a Monday morning, you can see hundreds of kids rushing through iron gates with nearly identical outfits and bouncing lunch bags if you walk past any primary school gate. It appears well-organized. deliberate. Even safer. However, a significant study from the University of Cambridge is posing a question that directly challenges that neat image: what if the uniform is actually getting in the way?
The study, which was published in the Journal of Sport and Health Science, used data from 135 countries that included over 1.1 million children between the ages of five and seventeen. That is a substantial sample. That survey was not carried out in a small number of schools in a single county in England. This is the most comprehensive picture of child health that researchers have been able to create, and the results are unsettling. Only about 16% of youth in nations where the majority of schools mandate uniforms were engaging in the 60 minutes of moderate physical activity per day recommended by the World Health Organization. That number increased to almost 19.5% in nations where uniforms were less common. Perhaps not a huge jump, but those percentage points add up to a huge amount of movement that isn’t occurring for millions of kids.
Because the researchers themselves are cautious, it is worthwhile to exercise caution in this situation. They make it clear that it is impossible to determine causation. A child is not inherently sedentary just because they wear a uniform. Other factors include access to green space, cultural norms surrounding childhood play, urbanization, and income levels. Dr. Mairead Ryan of Cambridge’s Faculty of Education, the study’s principal investigator, has made it clear that this isn’t a case for completely doing away with uniforms. However, the pattern is so consistent across nations and age groups that it would be wishful thinking to completely ignore it.
The data on girls is where it becomes more specific and, to be honest, more concerning. Boys are roughly 1.5 times more likely than girls to meet the WHO’s daily activity recommendations across all nations and age groups. On its own, that gap is a problem that needs to be addressed. However, the difference between primary school boys and girls increases significantly in nations where uniforms are mandated, from roughly 5.5 percentage points in non-uniform nations to nearly 9.8 percentage points in nations where uniforms are mandated in the majority of schools. It makes some intuitive sense that the effect is concentrated at the primary level. The cartwheels, climbing frames, and tag games that start as soon as the bell rings provide young children with a large portion of their physical activity. In contrast, regardless of their attire, older students are more likely to be sedentary throughout the day.
One of the research’s most memorable images is of girls in skirts hesitating at a playground’s edge instead of running on a windy day. The study’s senior author, Dr. Esther van Sluijs, put it simply. Children’s perceptions of their abilities in a particular outfit are influenced by social norms and expectations. Riding a bike, doing a cartwheel, or scaling a climbing structure might be uncomfortable for a girl wearing a dress. Her clothing conveys a message about propriety, how she should move, and what is expected of her, which may be the reason she holds back rather than a lack of energy. That’s not a theoretical issue. Similar concerns have been raised in Ireland, where researchers from the University of Limerick discovered that over half of students thought their school uniform was a barrier to physical activity during the school day. Previous research from England has found that girls’ PE uniforms specifically discouraged participation in certain activities.
However, the Irish research’s most startling figure relates to cycling. It was discovered that boys were about eighteen times more likely than girls to ride their bikes to and from school—a startling disparity. And the uniform was one of the most obvious explanations given. Cycling was just not feasible in schools where girls were required to wear long skirts. Exercise wasn’t being hindered by the uniform in some nebulous, atmospheric way. Physically, it couldn’t coexist with an active commute.
All of this does not imply that blazers should be burned in schools. Neither the Cambridge researchers nor the education researchers in Australia or Ireland are advocating for that. Look at the design—that’s a much simpler request. Think about whether girls could wear shorts or pants. On days when physical education is offered, allow students to wear PE attire instead of wasting ten minutes in a crowded changing room. Find out what the students feel comfortable moving into. These demands are not radical. These are minor changes that seem to have significant effects.
Scale, not novelty, is what makes the Cambridge study noteworthy. Smaller studies have previously raised concerns about uniforms and physical activity. However, a different kind of argument applies to 1.1 million children in 135 countries. It is more difficult to dismiss as a cultural edge case or a local anomaly. The data indicates that a consistent phenomenon is occurring worldwide, and clothing is the most likely explanation that researchers can offer in light of all the available data. It’s possible that more work is being done by other factors. However, mounting evidence eventually demands an answer rather than just more ambiguity.
A situation where children are encouraged to move more in official health messaging while the institution in charge of them spends the majority of the day dressing them in clothing that makes movement difficult seems a little ridiculous. Schools spend money on sports equipment, playgrounds, and physical education schedules. When a child decides not to bother with the climbing frame after looking down at what they’re wearing, some of that investment may be subtly undermined. That is something to take seriously.
