Free weekly boxing classes for teenagers have helped cut reports of anti-social behaviour in some parts of Nottingham by almost a quarter.
The training has been put together with help from police, the city council and former boxer Jawaid Khaliq.
The move has resulted in a drop in vandalism, petty crimes and aggressive behaviour, organisers said.
The number of anti-social behaviour incidents in the Forest Fields area fell from 620 to around 470.
"We are starting to build up a relationship with the boys and it means they are less likely to cause problems," Nottinghamshire Police said.
"It is building up a good strong relationship between the police team, the youth services and the guys on the street."
The boxing academy attracts between 10 and 30 teenagers each month.
"We are not really promoting violence and aggression. If anything parents and teachers have seen the exact opposite - they have seen them more sensible, more disciplined and more respectful," boxer Kamran Khaliq, who is the brother of former world welterweight champion Jawaid Khaliq, said.
"They know now that they can control their emotions and the aggression that they have."
One teenager said the training helped his self-esteem and gave him something to do.
Boxing lessons are helping youngsters stay off the streets, organisers say.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.