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.
