Ricky Lee Chun-hing, founder of Chun Hing Boxing School, is determined to help these teens get back on the right track through Muay Thai. Lee has been a volunteer trainer since 2000, when he was asked by a social worker to teach troubled youngsters Thai boxing.
'Martial arts movies are well loved in Hong Kong,' he says. 'Many youngsters hurt themselves when they try to imitate their martial arts heroes, so I'm there to teach them how to do it correctly.'
When he first started, many teenagers would challenge him during lessons, Lee recalls. 'Those young boys were quite aggressive. They did not believe I knew how to fight. I had to earn their respect by asking them to fight with me.
'In the first lesson, I always ask students to put on boxing gloves and try to hit me. I want to show them that without proper training, they won't be able to hit a thing, and mastering the sport requires years of hard work.'
Lee says learning Muay Thai will not make teenagers more aggressive - it will help them to stay away from trouble and find a goal in life. 'They come to the boxing school to train four to five hours a day,' he says. 'They don't have any more energy to hang out at night so they go home. They trust me and are willing to discuss their problems with me.
'When boxers go into the ring, they are fighting for glory. The trophy you win from a fight is something money cannot buy. It is something you have worked very hard for, and nobody can take that away from you. This is an important life lesson - you get what you want through your own efforts.'
Tsang Tsz-fung, 17, a student at Lee's school for the past two years, used to avoid going home, but says Muay Thai has completely changed his life. 'I have a goal to work towards, and I no longer hang out at video game arcades or snooker clubs.'
Tsz-fung says his family did not approve of his 'violent activity' at first, but they changed their minds after seeing him spend less time on the streets.
'Learning Muay Thai has helped me grow. I used to be timid, but now I'm more confident because I know what I am doing,' he says.