The results and attitudes to school of unruly and disaffected pupils can be improved by having one or two hours of extra sport a week, research suggests.
Sports on offer include rock climbing and kayaking
Across the UK, 11,000 pupils have been taking part in a scheme called Living for Sport, doing such things as archery, martial arts and boxing.
Loughborough University's Institute of Youth Sport found more than 75% of them later had better attitudes to teachers.
The pupils, aged 11 to 16, also had better attendance and punctuality.
More than 70% showed improved behaviour during the project and a similar proportion increased self-confidence.
Among teachers, 85% felt the project had benefited the pupils taking part.
The Living for Sport programme is organised by the charity the Youth Sport Trust (YST) and is aimed at children who are disengaged from school life and learning - mostly white boys.
Teachers put forward pupils whom they felt could benefit from the scheme and most were selected because of incidents of disruptive behaviour, as well as teachers' perceptions that they had low self-esteem.
In its first three years, more than 500 schools have been involved, offering activities such as martial arts, dance, rock climbing, archery, football and cricket to groups of up to 15 pupils.
The YST hopes to extend the scheme to other schools in the UK.
In a review of the first three years of the project, the Institute of Youth Sport at Loughborough found pupils and teachers noticed an improvement in behaviour and attitudes.
One pupil said: "I enjoy not getting into trouble and now I see what I am capable of doing."
Another said: "The project is good... we are learning about how to defend yourself... it makes us more confident."
A teacher was quoted as having noticed lots of changes among the pupils taking part. "They've become more confident and they've become more able to teach other people."
Senior development officer at the YST, Jenny Rouse, said: "When young people can appreciate discipline in a sporting context, it helps them to understand why their English or maths teacher wants them to sit still and pay attention.
"It is the same as their boxing coach asking them to do 10 press-ups."
The Living for Sport scheme is sponsored by the entertainment company Sky, which has put forward £1.25m.
The Department for Education and Skills has contributed £40,000.