That same confidence is evident as she talks about the training and nutrition which keeps her MMA career with Invicta and BAMMA Ireland going strong.

The Irish fighter is also a personal trainer under the rather cool banner of “Alpha Female Fitness”. How could you say no?

She said: “I have a lot of women who train with me, it’s not just about fighting. I do a lot of explosive work, we work with programmes like Tabata and all that cool stuff. It’s really different, much more exciting than just a regular gym. There’s been a real evolution in women’s fitness, it’s much more hands-on now.”

Catherine obviously lifts weights, and recommends this for anyone no matter what your sport.

She said: ‘It doesn’t have to be something huge, healthy muscle is good. Running on its own is grand but I don’t think it gives you the best physique you could possibly have as a woman.”

Diet is a big thing for Catherine, diet meaning healthy, clean eating. High protein, low-carbs is her mantra. When we first spoke she was in that dead week after a fight when sugar seems like a great idea. For an Atomweight fighter (c. 48kgs or 105lbs) every calorie counts.

She said: “I’m not feeling well, I’ve a cold and feel achy. That’s me back on the broccoli, off the chocolate. Fighters can get quite sick before or after cutting weight, our immune systems are so balanced. “You only get a certain amount of time to enjoy normal food!”

In the final weeks before a fight, she starts the day with bananas and a protein drink, then lunch is chicken breast and broccoli. Low-carbs, a lot of water and egg whites at night with greens like spinach to load up on nutrients.

“You do have to eat, it’s not enough to take protein drinks. You can taking them obviously but you need good food going into you to keep your metabolism going for training,” she said.

When it gets down to the final grams, she goes for salt baths over saunas, saying these work better for women.

Irish viewers will get a chance to see how her training stacks up soon with a major TV programme on women’s martial arts. Presenter Vogue Williams (who you might know from winning one of Bear Gryll’s intense adventures) even got into the Cage.

Catherine said: “She came to me, and did everything we do in MAA. She said it was amazing but she couldn’t understand how we think about everything that can possibly happen in a fight, she said it was incredible.

“Then she kept asking do you get hit in the “fionnuala”? I finally worked out what she meant so I said I’d gotten kneed in the “fionnuala” a few times, but I have a “fionnuala”-guard! She was really funny, she was asking how I train or fight with my period. I just do it really.

“It will be really good for MMA when it airs, getting someone like Vogue behind us is fantastic.”

Read the first part of this interview: Costigan on MMA, surgery and ignoring age limits