Sylviane Puntous beat her identical twin Patricia into the world by two minutes, and thereby got things started. That was their first close finish; there have been many since then.

The Puntous twins, who are counted among the top five female triathletes in the world, have spent much of their 27 years racing each other. What's more, they often find themselves dueling none other than their own mirror image in the late stages of a triathlon. In their 86 races since 1982, they have finished 1-2 68 times. In their five races this year, they have finished tied for third, 2-3, 2-3, 1-2 and 1-3.Curiously, Sylviane still has the upper hand, usually by one or two minutes - just as she did at birth. "Sylviane seems to win the shorter races and I win the longer ones," says Patricia.

But there is always another day, another race, on the long, exhausting triathlon circuit. And the next one is just around the corner. On Monday, the twins will battle the likes of Kirsten Hanssen, Erin Baker and Colleen Cannon, not to mention each other, in the rich (81,000 in prize money) Heritage International Triathlon in Provo.

"Everybody will be good who's there," said Sylviane from the twins' home in Kelowna, British Columbia. As for another race with her sister, Sylviane says, "We are usually less than a minute apart," says Sylviane. "We're very close."

Indeed, they live together - and it has never been otherwise - train together, race together and, in their spare time, visit terminally ill children together. They seldom are apart. "It's a lot of fun, we get along very well," says Sylviane. "She's my best friend."

But aside from the novelty of being twins, they are much more than a sideshow. They are forces on the triathlon tour. Sylviane and Patricia finished 1-2, re spectively, in the Ironman Triathlon in both 1983 and 1984, the later in record time. In 1986 they finished 1-3 in the Ironman, although Patricia was eventually disqualified for drafting, a charge she disputes to this day.

"They strike fear into the heart of all the women," says Jerry McNeil, a freelance triathlon writer/expert/commentator. "If (reigning Ironman champion) Kirsten Hanssen suffers a rare loss, it's apt to be Sylviane. (the twins) are both excellent runners, particularly Sylviane."

Like most triathletes, the twins' athletic career began in another sport. While growing up in Montreal they began as age-group swimmers, then they turned to track, where they became national-class 3,000-meter/1,500-meter runners. Six years ago they took up triathlons - "because of the challenge and because of running injuries," says Patricia - and they have made the sport a full-time job since then.