Auckland-based event organiser Sly Natty said the online portion of the competition started small, with around 200 athletes in 2012. The numbers have now tripled.
The top 24 mums in each category in the online event get invited to an in-person competition in Auckland.
Gisborne mums took six podium spots at the last event in February.
"We do see lots of mums coming from Gisborne," Natty said.
"When they come they are always friendly and having fun."
Mums from Gisborne gyms Maia Fitness, CrossFit 4010 and Metcon Mauri are competing in the 2022 Fittest Mum.
After working 20 years in the health and wellness sector, Maia fitness owner Stephanie Broughton said many people in society were not being catered for, especially Māori.
So with the help of her whānau she opened Maia Fitness.
"Everything we do is kaupapa Māori," Broughton said.
"We have tikanga in here so we don't have rules.
"We don't refer to ourselves as a gym, we are a where.
"We don't refer to our members as members, they are whānau," she said.
Broughton's mother Yvonne entered the Fittest Mum competition for the first time aged 62.
She began CrossFit after seeing her granddaughter Kalani participating.
"Just to say I competed, just to say I've done it and let my mokos see that I done it," Yvonne said.
CrossFit 4010 mums Tamera Nelson and Debbie Hutchings have been doing CrossFit for more than 10 years.
Tamera Placed 1st in the RX 35+ division and Debbie placed second in the RX 40+ division in the February competition.
First-time competitor Sarah Hunter entered to challenge herself after doing CrossFit for just six months.
"I really love it," she said.
"On a Sunday all the mums come down to do the workouts and are really supportive. It just keeps you going, as opposed to doing it on your own."
Metcon Mauri mother-of-five Mandy Campbell said peer pressure from her gym friends was the reason she entered.
"It's not about the workouts anymore it's about getting here, doing it. And sanity.
"We are a group of women who probably would have never met but CrossFit brought us together," Campbell said.
Follow Fittest Mum's Facebook page to keep up with the online leaderboard.