It was great to be one of the few in the country to achieve the status, she said.
"We really want to bring Strong First into New Zealand," she said.
"They have what they call the gold standard.
"They really know what they are talking about. With Strong First you learn how to do stuff and the reasons behind it."
Kettle bells built "functional strength and use your body the way it was designed to move".
She said the course was incredibly tough.
"It was really hard. I didn't think I was going to pass. The second day I just broke down in tears saying 'I've come all this way, I just don't know if I can do it'.
But she did and will be going back to Australia later this year to complete the level 2 training.
"Now being Strong First certified it gives me just that little bit more cred. Especially with people in the fitness industry who know who Strong First are."
In 2010 she studied a certificate of exercise and sport performance at Ucol and 18 months ago decided to set up her own gym Iron Alley.
"I had a different direction from where I was working. I kind of felt that I needed to expand," she said.
Now Mrs Eru takes her own clients and runs group classes.
"I like everything about it. I like seeing people achieve. To set their minds to something and do it.
"It's not your conventional gym. What we use is all free weight," she said. "We say that we don't use machines, we make them."
