Matthew Murray has lost the bulk and said he now enjoys more functional body movement.

"I wasn't able to make the same sort of movements I saw on the Ninja Warrior TV series," the HIIT Nation gym owner said.

"I love the show and this style of training, I love what the athletes can do.

"I wasn't able to do (these things) being a bigger size."

A fitness trainer for seven years Mr Murray now runs ninja warrior-style classes, with children aged between nine and 13 forming the majority of his students. Classes for adults, group bookings and corporate packages are all available upon request.

"I have had some students as young as five-years-old coming with their siblings," he said.

"It's so much fun, they have a ball jumping, running and swinging around, all the things that kids love to do.

"At the same time there is a bit of competition in it and they are getting fit without realising it."

Ninja warrior training class are held on Wednesday night from 5-6pm, with an open session on Sunday between noon and 2pm.

"We work with them to build on their basic movement patterns," he said.

"On Sundays we encourage parents to have a go with their children."

The sessions focus on functional body movement training to match everyday activities, working up the same sort of muscles as a gym session but in a more natural way.

"We focus on compound exercises working as many muscle groups at the same time as possible," he said.

Mr Murray also conducts high intensity interval training (HIIT) classes.

"These are a short and sharp training session," he said.

"They work well alongside the ninja training which focuses on balance and upper body, while the HIIT training can be leg heavy."

Classes are held at the Spartan Martial Arts facility on Timor Street. More information on class times can be found on the HIIT Nation Facebook page.

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