"When I first got asked to be captain, I think the day after that I felt this extra level of fire to train even harder. You want your captain to be on the court for full matches and leading the way, so I knew I needed to work harder than ever."
Which is why in the lead-up to this year's international season, Grant could be found here at High Performance Sport NZ's elite training facility in Cambridge - an hour's drive away her new home base of Rotorua - from the early hours of the morning.
It is that level of commitment that has allowed Grant to remain a fixture in what has traditionally been the most competitive area of the court for the Silver Ferns for the past 10 seasons.
On Wednesday night in Hamilton, Grant will step out on court for her 100th test when her side take on England in the final match of the Taini Jamison series.
The match is a big one for the Ferns.
England are on the brink of securing an historic series win over New Zealand after pushing the series to a decider with a gutsy 49-46 win in Napier on Sunday.
It is the second time in the space of two weeks the Kiwi side is under huge pressure to deliver an emphatic response after a disappointing showing against the Roses in their Quad Series match-up last month.
'I've done some stupid things on court'
Approaching her milestone game, Grant has undergone one of the biggest leadership tests of her career.
Grant was considered by many to be a controversial choice for Silver Ferns captain.
Hell, she was even surprised when coach Janine Southby sat her down at the end of last year's final transtasman league season and asked her to take on the role.
Her career with the Pulse has been marked by a couple of incidents where her discipline has been called into question - the most infamous being her foul-mouthed tirade at an umpire in the immediate aftermath of her side's 55-all draw with the Southern Steel in 2015.
That incident earned Grant the ignominy of being the first, and only, player to front a judicial hearing in the old transtasman league - a black mark against her name she was certain would have ramifications for her Silver Ferns career.
"I definitely did worry about how that would affect things with the Silver Ferns. Being the captain [of the Pulse], you shouldn't do that type of carry on and I knew I had let myself and the team down," she said.
So when Southby assigned Grant a series of tasks early in the 2016 season, the national captaincy was the furthest thing from her mind.
"I didn't actually know what she was doing at the time," said Grant.
"It was a season that had been quite tough for us at the Pulse, I hadn't been playing very well and then Janine gave me these tasks to do. I knew at that point I needed to focus on my own game and sort a few things out."
Grant believes some of the long, difficult seasons at the Pulse have helped her build resilience and made her a better player and leader.
"There's no doubt I've done some stupid things on the court, but mistakes help you learn and grow and I am definitely a better player for having my mistakes," she said.
"I'm still a competitor and my teammates will know I will do whatever it takes for us to win, and as long as they trust in me to do the job, that's all that matters really."
Destined for greatness
Silver Ferns assistant coach Yvette McCausland-Durie considers herself fortunate to have witnessed Grant's coming of age up close.
The amiable coach first came across a teenaged Grant when she was a member of the New Zealand U21 side that went on to win the World Youth Cup in 2005.
What she saw from Grant in that campaign was a fringe player that played the perfect support role in every sense.
Her easy-going nature, quick wit and openness made her a well-liked team member, but the tenacious defender worked hard to ensure she was a strong option off the bench.
That determination to be better has served Grant well throughout her career, ensuring she held her place.
"Looking back now it seems obvious she was always going to do great things, but I know Katrina has worked incredibly hard to get to this position," said McCausland-Durie.
"What you've always known with Katrina is that she is fiercely competitive and you see that in everything she does.
"She has a real determination ability to self-focus and that hasn't changed, she has just become a lot more attuned in all parts of her life."
Her personal development has manifested in a physical way.
Grant's impending milestone has brought on a bit of nostalgia in the Ferns camp, with the team looking back on images and footage from her 2008 debut against Australia.
"There's this photo of us all when I first got in the team and my face looks completely different.
"I have chubby cheeks, my legs are way bigger, we were all having a good laugh at it," the good-natured defender said with a chuckle.
"I was 21, I was in Dunedin and having a really good time. You don't really know what you're up to."
Silver Ferns trainer Stephen Hotter, who recently left his Wellington base to take up a job with High Performance Sport NZ in Cambridge, said the photo is a good example to young players what is possible when you show "total commitment to being a Silver Fern".
"She's certainly an athlete that over a period of time has made significant development.
She has completely altered her body type, especially over the past three years," said Hotter.
"Just last week at our training camp she was doing PBs in the gym. She is still constantly tracking up."
From support act to anchor
Of her debut match, which the Ferns won 38-31 - a scoreline that suggests the defenders had a strong influence on the game, Grant remembers coming off the court on a high and thinking she wanted to wear the black dress forever.
Among the exclusive group of players Grant will join in the 100-club are two of her former defensive buddies Casey Kopua and Leana de Bruin.
The trio, along with versatile defender Anna Harrison, were the rocks in the New Zealand defensive end for the best part of a decade.
When all four were fit and available, the Silver Ferns defensive end picked itself.
The retirements of Kopua, de Bruin and, most recently, Harrison over the past 18 months means Grant is now the last pillar standing.
"I've been there since 2008 and over that time it was pretty much the four of us, except when there's been injuries or pregnancy.
"It's crazy to think how long we were all together fighting for positions and fighting for court time," said Grant.
"It is kind of sad that all my friends I've played with for so long have one by one disappeared, I just looked around one day and was like 'hey, where is everyone?" she joked.
"It's definitely helped me as a person to grow and understand how hard you have to work to stay on top. It also helps you appreciate how hard it is to be selected."
Given the Ferns previous riches in the defensive end, it was only last season that Grant began regularly playing full games at international level.
The support act has become the anchor.
Grant admits it was a bigger adjustment than she expected, as having an impact on the game across four quarters proved markedly different to be given the job of trying to wear a goal attack down for 30 minutes.
The quick succession of retirements has also left Grant with the challenge of needing to urgently build combinations with a new generation of defensive stars as next year's Commonwealth Games loom.
It's a task she has taken to enthusiastically, with the 30-year-old genuinely excited by the fresh talent that has been injected into the Ferns ranks.
One of those up and coming young stars, Hamilton-based Kelly Jury, trains alongside Grant in Cambridge when the New Zealand side is not in camp.
Grant watches intently as Jury goes through the same dreaded treadmill sprint sequence, encouraging the long-limbed youngster to keep pushing.
"I know that feeling," Grant sympathises with a doubled over Jury.
Shortly after, the youngster wearily stands up and gets back on the treadmill.
