Kirsty Rodgers and John McFetrich first met when they were children. They have been fighting ever since.
"Kirsty's known me since I was that height," says McFetrich, with the palm of his hand at knee level.
"We are pretty much joined at the hip."
At 24, he is seven years Rodgers's junior. The pair hail from Port Glasgow in Inverclyde, and together they have been trying to push up the rankings to represent Scotland in judo at this summer's Commonwealth Games.
That looks an increasingly slim prospect, with injuries, work and study commitments, and the standard of competition making participation at Glasgow 2014 unlikely.
However, their commitment to the sport is praiseworthy. They work on groundwork and standing judo at the Port's Boglestone club several times a week.
To practise throws, they make the 100-mile round trip together to Judo Scotland's headquarters in Ratho, west of Edinburgh.
And on another evening they travel to East Kilbride to train with Gary Edwards, who has them hill-running for two hours before spending the same amount of time working on specific techniques on the mats.
It is clear they enjoy one another's company, which is just as well. There is plenty of laughter in their conversations.
McFetrich fights at under 100kg, which is unfortunate in one respect - it is the same weight as Olympian Euan Burton, who tops the Scottish men's rankings and looks certain to be named in Team Scotland when the judo places are revealed on 28 May.
Rodgers competes in the over-78kg class. At times there are only a handful of kilos between the duo.
"It's good that we train together because, even though Kirsty is a lady, she is still quite strong," says McFetrich, who has been competing for 13 years.
"She gives me a run for my money. It's quite beneficial."
His good friend agrees.
"I get the extra strength training because I'm fighting against a guy," she says.
"He gets to use more technique because I've not got as much strength.
"He trains with men his weight. I mostly train with men but it benefits me when I go to competition."
Their friendship brings other sporting benefits.
"It's good when you can talk to someone on the same level," says McFetrich.
"A coach is seen as an authority figure.
"It's good to have that friendship, to be able to talk to them and have a shoulder to cry on, as it were."
Rodgers adds: "We just bounce off each other. We push each other to train harder.
"We slag one another off if they are getting a bit fat. It spurs us on a bit.
"He coaches me. He shouts at me when I'm doing something wrong. It's funny, I've known him since he was a wee toddler."
Rodgers juggles the sport with other major demands - motherhood and the latter stages of a nursing degree.
She says of judo: "It's something I enjoy doing so it's not hard to put the time in. I just cut back on the social life. I study and do what I can.
"There are times when I can put more training time into judo and there are times when I put more into studying."
The physical exertion required in judo is in contrast to McFetrich's job, where he spends a lot of time behind the wheel of his car working as an area manager for a facilities management company.
Like his friend and training partner, he is trying to fit in coursework for exams in his chosen field.
In addition, his Commonwealth plans have been badly hampered by a knee injury in the second half of 2013.
"It's trying to balance everything, making sure my career isn't going to be affected by judo and vice versa," he explains.
Of his career to date, he speaks of his thrill at training with Olympians, of competing at tournaments abroad and experiencing different cultures, notably the strict adherence to dojo etiquette in Japan.
"You hope to get noticed by the national coach and get your name on that magical list for Glasgow," he says.
"But I don't think it's the end of the dream if we don't get to the Commonwealth Games.
"There are the Olympics in Rio and the next Commonwealth Games in Australia, so fingers crossed there will be more opportunities."
Rodgers claimed a bronze medal at the Scottish Open at Meadowbank in January, winning twice by ippon but also losing twice. Fighting in an open weight category, one of her opponents was 80kg heavier than her. She ended the tournament with a black eye.
"I was seeded first in GB at one stage, but there were world rankings at my weight and they were better players than me," she says.
"I think I've got another two or three years in me, hopefully.
"I'm going to keep competing until I get beaten every time...and then I'll take up ballet or something."
It would be hard to grudge Rodgers enjoying a less bruising activity. For her lifelong pal, retirement from judo is a long way off.