Team sport is the only type of extracurricular activity to make a significant and consistent difference to students' academic grades, new research has found.
Students who belong to extracurricular sports clubs, unlike those who participate in other activities such as drama or debating, are also more likely than their peers to complete their school education and go on to university.
Academics from the University of South Carolina and Pennsylvania State University, both in the US, studied data from 9,700 high-school students aged 14-18. The students attended schools in a range of urban, suburban and rural areas. They participated in a variety of extracurricular activities, including academic and vocational clubs, performing arts societies and team sports.
The academics looked for correlations between the types of after-school activities undertaken by the teenagers and their school success, including the likelihood of progressing to higher education.
They found that students who lived in the countryside were more likely to take part in all kinds of extracurricular activities than their city-dwelling and suburban peers.
But the researchers' most significant findings came when examining the effect of these after-school clubs on students' academic achievements. Team sport was the only extracurricular activity to have a consistent and significant effect on students' grades across all schools.
"Team sport is significantly related to higher grade-point averages and a higher likelihood of completing high school and enrolling in college," said Matthew Irvin, assistant professor in the Department of Educational Studies at the University of South Carolina, and the paper's lead author.
This was true, he added, even once students' race, sex, previous academic achievement and socio-economic background were taken into consideration.
"Sport allows you to develop a mentoring relationship with adults and with positive, school-oriented peers," Professor Irvin said. "They help socialise you into being more focused on school, and may help develop time-management skills, initiative and an ability to work with others."
Eileen Marchant, of the UK's Association for Physical Education, said that being "physically able and physically competent often complements academic ability".
"It raises self-esteem and self-belief, and there's an absolute correlation between believing in yourself and what happens in other areas of the curriculum," she said.
Other activities were not without benefits, however. In urban high schools, for example, students who enrolled in academic clubs were likely to progress to college. And rural students who signed up for vocational or performing arts societies were also likely to go on to enrol on a degree course.
The academics found that the positive effects of such activities remained the same regardless of students' socio-economic backgrounds. "School extracurricular activities may be equally beneficial for youth experiencing poverty as for youth in more affluent conditions," the paper states.
But only sport had a consistently positive effect across all schools and all measures of academic success.
"Sport is often what brings a community together," Professor Irvin said. "The big event for the weekend is the high-school football or basketball game. It's what children are participating in. Maybe there's just more personal interest, more opportunities. They want to do it."
Ms Marchant attributed the positive impact to sport's competitiveness: "So much of extracurricular sport is focused on games, which are competitive. Additionally, you're competing against yourself in PE, even in something like dance or gymnastics. Success does breed success. There's no doubt about it."
"I've always said: give me a good PE department and I'll give you a great school," said Rod Goldswain, acting headteacher of Northampton School for Boys in England, which places particular emphasis on extracurricular activities for its 11- to 18-year-old students.
"Those who do well in life are those who put the maximum effort into their sporting activities," he said. "That doesn't mean they have to represent their university. It doesn't mean they have to play on a national level. But when they take part, they're determined. When they train, they want to do their best."
But, he added, this can also apply to other extracurricular activities: "In all extracurricular activities, whether dance or drama or whatever, when students are determined to do well, it's a mindset. Having determination has an effect on their lives."