Much to the chagrin of his younger sister, William stubbornly refused to pass her the ball. "It caused a lot of trouble," he laughs. "We were definitely competitive."
Beside him, Kareena smiles. "I would get so frustrated with him," she says. "We used to hit each other."
Two decades on, it is a different story. As both work towards competing at their second Commonwealth Games, the emphasis is on support, not sibling rivalry.
They are quite the double act at Glasgow Green National Hockey Centre, cajoling and teasing each other in equal measure. Their mother Judith is a former England international so it was perhaps inevitable they would follow in her footsteps, albeit for their native Scotland. William started playing hockey at six and Kareena "tagged along" two years later, aged seven.
"It was all down to mum," says William. "We'd go down to watch her play hockey and be at the side of the pitch messing around. I remember one game where mum got hit on the hand when she was playing."
Kareena takes up the tale. "When she came off, her fingers had all swollen up massively. In the end, I think she had to get her rings cut off."
But even that didn't put them off. They joined Greenock Hockey Club, where they stayed until they were 16 and 18, before William moved to Kelburne Hockey Club in their hometown of Paisley and Kareena to Giffnock HC on Glasgow's south side. After a decade with their respective clubs, last year William, 28, joined Sheffield Hockey Club, where he also works as a development officer, encouraging children to take up the sport, and Kareena, 27, now plays for Milngavie-based Western Wildcats.
Both are regulars in the senior Scottish squad, with Kareena garnering 68 international caps while William has 111. Having made their Commonwealth Games debut, in Delhi four years ago, they are grateful for having had that exper-ience as they target Glasgow 2014.
"If this had been our first Games I think we would have been nervous and a bit daunted," says William.
Kareena, who works in Glasgow as a physiotherapist specialising in musculoskeletal injuries, agrees. "It's a lot to take in," she says. "Hockey is a massive sport in India so we played in a stadium in front of 20,000 people. It was sell-out crowds. That, for me, was quite something to get used to, the fact that you can't hear your team-mates on the pitch because there is so much noise.
"Those crowds weren't necessarily cheering for us, whereas in Glasgow the place will be hopefully sold out with the majority of people behind us, which will be phenomenal. In that respect, Delhi was good preparation as it's definitely the biggest crowd I've ever played in front of."
When it comes to home advantage they intend to make full use of being based at Glasgow Green National Hockey Centre. "People often underestimate how important that will be," says William. "Each pitch can have a different grain, for example, which affects how the ball will move. Getting to know those little details can be a massive advantage.
"Having the home crowd behind us too. If you look at London 2012 and the difference that made to Team GB."
They admit to being chalk and cheese when it comes to their personalities, with Kareena the super-organised one, and William much more laid back. "I don't worry about things, I just let them happen," he says.
His sister laughs. "That's probably the biggest bug bear between the two of us," she adds. "It drives me mental."
But they aren't completely unalike, both having carved playing successful careers as defenders. "I started up front and as I got better, I moved back into midfield," said William.
"You got relegated," Kareena jokes.
Ignoring her, he continues: "Passing is the strongest part of my game, so midfield and defence is the best place for that."
The pair admit that being in defence doesn't always earn the plaudits. "To play for a Scotland team, being a defender is up there as a job - we do a lot of defending," says Kareena. "Strikers get the credit for scoring the goals. As a defender you may not get the same write-ups, but you do get the gratitude of your team-mates for a good game."
William and Kareena have to wait until May to find out if they have made Team Scotland for Glasgow 2014. The women are in a group with Aus- tralia, England, Wales and Malaysia, while the men will face Wales, Australia, India and South Africa.
The women's side received a £60,000 investment from the sport-scotland Athlete Personal Awards scheme, allowing the 20-strong squad to train full-time in two blocks leading up to the Commonwealth Games to maximise their chances of a medal.
"We had three months full-time training during the summer and went to a European tournament where we found we could compete with the top teams and maintain our A division status," says Kareena. "Those three months made a massive difference to our consistency and performance."
They will enter a second phase of full-time training on April 1. "It does make selection a lot harder because, while some people may have been seen as a dead cert before, suddenly everyone is up there and playing well, putting themselves into contention to make that team. That can only be a good thing because we want to go into Glasgow with the strongest players and best possible team."
The men's team will start their final preparations in April. "We go part-time then and I'll be training Thursday until Saturday every week," says William.
Last month saw William compete in the EuroHockey Indoor Champion- ship in Bern where Scotland finished fifth, beating Slovakia and Belgium and drawing with France, while the women's Scottish outdoor squad are due to fly to South Africa for a training camp and Test series next weekend.
With less than six months to go to the Games excitement is growing. "If I make the team the thing I'm most looking forward to is playing in front of my friends and family," says Kareena. "They know I go away on all these trips to different places, but they don't really understand what it's like when we are competing. Having them among the crowd supporting us is going to be amazing. I can't wait."