"They did amazing, very happy. We had several first-time competitors who did really well," she said.
Novices Megumi Kusano-Whetton and Chelsey Stratton-Smith placed first and second in the shape category.
In the 35-plus age group, Jess Solly took first place in the shape category also.
Ash Waugh rounded out the first-time competitors, placing third in the novice men's category.
McCosh said it was inspirational to see people come in the door and transform themselves through dedication and commitment.
"To see people blossom, that is why I do what I do. To see people come out of their shells and feel healthy, energetic and confident and just shine," she said.
"It is so cool to see them actually hit the stage and strut their stuff."
Jess Williams and Leanne Bird rounded out the winners for ReVitalise, placing first in open figure and shape, respectively.
Competitors are judged across a variety of categories; including their physique, their deportment, movement and more.
Posing plays a crucial part when it comes to judging, McCosh added.
"Every Monday, we have posing practice. If you don't pose right, you can lose a show. Posing is most important. It's not about how you look, it's about symmetry as well as showing off your muscles.
"If you pose wrong, you are not going to show off your muscles."
Lacy, who came first in the physique category and was crowned Mr Manawatu/Wanganui, said the win was a long time coming.
A one-time competitor over five years ago, the 49-year-old said the door was slowly closing on him to try it again.
"It was really awesome actually. I've been dieting from October 1 in preparation so it was great to get the win."
Lacy started going to the gym as part of his rehab after an injury put him on ACC. Once he started working out, he never stopped.
"It just kept developing and growing.
"I got married in January and my wife has been so supportive. We live busy lives with lots going on, but she helps keep me grounded."
Training at CityFitness, but under the coaching and dietary regimen of McCosh, Lacy was looking forward to having a bit of a rest before ramping up the preparations for the nationals in October.
"It will be a busy four months. There will be some good guys and I'll need to step up.
"Thanks to everyone from ReVitalise and Mayhem Supplements who have helped me over the last few months."