The study, which was led by Dublin-born Dr Mairead Ryan, a researcher at the Faculty of Education and MRC Epidemiology Unit at the University of Cambridge, analysed data relating to the physical activity of more than one million children aged five to 17 in 135 countries.
In countries where a majority of schools require students to wear uniforms, fewer young people are meeting World Health Organisation (WHO) recommendations for daily levels of physical activity.
Fewer girls are reaching essential activity levels than boys, and the gap between them widens at primary school level in countries where uniforms are the norm.
Today’s News in 90 Seconds – February 15th
While this does not definitively prove that school uniforms restrict children’s physical activity, it corresponds with the findings of previous, smaller studies that have suggested uniforms could be a barrier to improved physical health.
The Oireachtas Health Committee was told yesterday of concerning levels of obesity in young children as well as adults.
The new study found that in countries where a majority of schools require students to wear uniforms, fewer students tend to meet the daily recommended 60 minutes of physical activity.
Regardless of uniform policies, across most countries fewer girls than boys reach those recommended exercise levels. Among primary school students, however, the difference in activity between girls and boys was found to be bigger in countries where most schools mandated uniforms.
The same result was not found in students of secondary school age.
The authors say this could be explained by the fact that younger children get more incidental exercise throughout the school day than older students – for example, through running, climbing and various other forms of active play at break and lunchtimes.
There is already evidence that girls feel less comfortable participating in active play if they are wearing certain types of clothing such as skirts or dresses.
Importantly, the results do not definitively prove school uniforms limit children’s physical activity and the researchers stress that “causation cannot be inferred”.
Previous, smaller studies have supported these findings, indicating that uniforms could pose a barrier. For the first time, the research examines large-scale statistical evidence to assess that claim.
Dr Ryan said: “Schools often prefer to use uniforms for various reasons. We are not trying to suggest a blanket ban on them, but to present new evidence to support decision-making.
“School communities could consider design and whether specific characteristics of a uniform might either encourage or restrict any opportunities for physical activity across the day.”
The study confirms previous observations that most children and adolescents are not meeting this recommendation, especially girls.
The difference in the percentage of boys and girls meeting physical activity guidelines across all countries was, on average, 7.6 percentage points.
A 2021 study in England found that the design of girls’ PE uniforms deterred students from participation in certain activities.
Children often get their exercise away from PE and sports lessons, but “activities like walking or cycling to school, breaktime games and after-school outdoor play can all help young people incorporate physical activity into their daily routines”, Dr Ryan said.
“That’s why we are interested in the extent to which various elements of young people’s environments, including what they wear, encourage such behaviours.”
The study, in the Journal of Sport and Health Science, analysed existing data and combined this with newly collected data on how common the use of school uniforms is in these countries.
In over 75pc of the countries surveyed, a majority of schools required their students to wear uniforms. The study found that in these countries, physical activity participation was lowerr.
“Girls might feel less confident about doing things like cartwheels and tumbles in the playground, or riding a bike on a windy day, if they are wearing a skirt or dress,” said senior author Dr Esther van Sluijs. “Social norms and expectations tend to influence what they feel they can do in these clothes.”
