Sunbury police believe the single-most important factor in the turnaround was the opening of the Police and Community Youth Club, which offered a cheap alternative for bored youngsters.

The PCYC is going strong, bolstered by a recent donation from Sunbury's Helping Hand, the independent committee that decides how to distribute community grants from Bendigo Bank.

"The $1500 donation will pay for the VCAL class for the Macedon Ranges and Sunbury Specialist School," said Stuart Ritchie, manager of the gym at the PCYC.

The course, run by Mr Ritchie, covers health, nutrition, anatomy and diet.

During the day, the gym, tucked in between light industries on Harker Street, hosts school groups doing similar health and physical education courses. Then after school many students call in for general fitness training. "We write out a program and show them how to use the weights and so on," Mr Ritchie said.

After 7pm, boxing and kickboxing classes are open to all ages. At $60 for three months' membership, few places offer better value.

"In total, we'd get about 300 kids through here a week."

Some have gone on to take a gym instructor's course and have worked at the centre.

Sunbury police Sergeant Trevor Hine is at the gym at least twice a week, running assessment classes or just chatting with the youngsters. As well as being president of the Sunbury PCYC, he is president of the Victorian PCYC body. There are eight centres in Victoria and Sergeant Hine hopes to open two new ones every year.

He still does his shifts on the beat too. "It makes a difference when I'm out on the street, knowing the kids.

"But I need to get out on the beat too. If I'm just Trev at the gym with no police duties, then the kids wouldn't see me in the same way.

"Working with kids from grade 5 upwards, I feel we make the biggest difference when we can work with that age," the father of four said.

"Some of the kids have intellectual disability and some are struggling with things at school and so I just listen to their stories - and they're interesting."

Sergeant Hine said there were four rules at the gym: be nice, stop on command, don't physically hit anyone, and be nice to your mum.

"The computer age is fantastic, but things change so dramatically and I feel the old-fashioned values, like respect and the way we treat people, are very important."