"I was quite fit and slim and Dean said, 'You need to do some resistance training for bone density', and replied, 'I don't what that means, but I'll try it," laughs Ms Harris.

Fast-forward and the Union Street, Merewether gym is marking 20 years in business, with Harris moving from client to owner seven years ago, and Shedden remaining as manager.

Ms Harris says the gym has drawn and helped a "strong, long standing community with the elder people of Newcastle and Merewether."

That community includes a 90-year-old woman who walks five kilometres in the morning and then arrives to leap on a row machine.

Ms Harris, 45, guesses that up to 70 per cent of clients at the gym are her age or above.

"The young people we have tend to be old souls and love hanging out with older people. We have a nurturing environment and the older people motivate me for how amazing they are," she says.

Ms Harris owned companies in finance and property until 2011, when she bought Fitness Junction, about the time she obtained a diploma in fitness and nutrition.

She made a few tweaks, including renting a bigger premise to accommodate allied health staff - a physiotherapist, remedial massage therapist, nutritionist, naturopath, herbalist, hypnotherapist and yoga teacher.

"It is a holistic centre so we have an internal network, also to share the cost of rent, because it's not a highly profitable business," she says.

Having dipped her toe back into the finance sector, Ms Harris still works three days at Fitness Junction and works on the business daily with Shedden and office administrator Michelle Bourne.

She says the gym's point of difference is its personal service in a supportive group setting that is affordable.

"Each client has a relationship with trainers and they all do their own program on the day they come in - clients can have input depending on how they present on the day," she says.

The gym has about 150 rotating members from a database of 300 who fluctuate depending on other training.

Client communication is a focus, so too staying true to a sensible approach of helping clients improve themselves and their lifestyle with minor, healthy and permanent changes rather than fad-driven diets.

The fact the gym hasn't changed its model has, she says, worked in its favour.

"When we began we were the first doing personal training - there weren't Cross Fit or high intensity training gyms," she says. "They are all the rage and we do those sorts of programs but we haven't converted to that."