Wai Weight today offers membership by referral, or at the owners' discretion, and is the training centre for four world champions including Joel Hintz (2014 world champion powerlifter); Fa'avae Sefo (2013 world single saw champion); Zane Hopman (2014 Muay Thai world champion kickboxer); and Brett Gibbs (2014 world champion powerlifter).
Mr Mackenzie and his wife have each won national medals in bodybuilding, and he had been often urged to open similar operations in other areas and regions, he said, but had instead concentrated his efforts on the Masterton business while also helping friends open a small gym in Greytown.
"I've tossed and turned about opening somewhere else, but I don't want this gym any bigger. It might become like any other gym. The members here seem to love the atmosphere, which is created by the people. I don't want to lose that."
Mr Mackenzie said he also was involved with teachers who were gym members, and had helped intermediate school students develop training regimes at the gym as an incentive for good behaviour in class.
"It's just for ten weeks but it gives the kids something to look forward to."
Mr Mark praised the arrangement, which he said would also offer pupils "structure and discipline, goal-setting and satisfaction, and world champions as role models".
"You couldn't ask for better people to help and provide incentives to the young," Mr Mark said.
"You're not just a Wairarapa success story, you're a Wairarapa role model and a very unique and successful business model. If I was one of the traditional gym operators, I'd be worried about someone like you."