When Gar Williams and Ralph Reynolds organized the first Nike Cherry Blossom 10-Mile run in 1973 to coincide with the Cherry Blossom Festival, they never imagined how popular the race would become. About 100 runners finished that first race, a large field at the time.

But the race has grown steadily over the years, so much so that in 1981 organizers limited the number of entrants to 4,500 on a first-come, first-served basis, for safety reasons. For the 13th running of the race, scheduled Sunday at 8 a.m. in West Potomac Park, more than 12,000 men and women applied to run.

The race ranks as the second biggest 10-miler and 68th biggest race in the country. Three-time race director Phil Stewart estimates that if entries were not limited, the race would be among the 10 biggest in the U.S.

"Back in 1973, we really couldn't see the boom that was coming, although we hoped the race would be popular," said Williams, then president of the D.C. Road Runners Club, who now lives in Denver. "We wanted to bring to Washington a high-visibility race that didn't conflict with other races on the schedule. And April was a good time of the year . . . "

The race has certainly been visible, but the weather has been anything but favorable. In 1975, 575 finished the race despite Artic-like temperatures. In 1981, race day was warm and windy, but the next year 4,500 entrants fought 55 mph winds along Hains Point. Although there never has been rain for the race, last year the Potomac River crested and caused the runners to splash through ankle-deep water along with a stiff wind.

The reputation and timing of the Cherry Blossom, usually two weeks before the Boston Marathon, have attracted numerous world-class runners. Bill Rodgers (Cherry Blossom winner from 1978 through 1981) and Greg Meyer (Cherry Blossom winner in 1983) each went on to win at Boston. Meyer's winning time of 46 minutes 13 seconds established the existing world best for a 10-mile road course. Last year's winning woman, Portugal's Rosa Mota, earned the bronze medal four months later in the first Olympic women's marathon.

The tradition of world-class competition continues this year as Simeon Kigen, a student at the University of Colorado, is favored to defend his 1984 title (47:25) in a race that includes 12 Olympians from seven countries. Kigen was among the favorites for the 1984 Olympic marathon until he was dropped from the Kenyan Olympic team for failing to comply with an order to report to its Olympic training site -- an order Kigen said he never received.

Kigen could be pushed by England's Charlie Spedding, the '84 Olympic marathon bronze medalist; Jon Sinclair, the '84 TAC 10,000-meter track champion from Fort Collins, Colo.; England's Martyn Brewer, fourth in last year's Nike Cherry Blossom, and David Edge, a 1984 Canadian Olympian.

The women's field features Lisa Larsen Weidenbach of Marblehead, Mass., last year's runner-up by one second. She will be returning against two-time Cherry Blossom winner Eleanor Simonsick of Baltimore (course record-holder in 53:46, 1983); New Zealand's Lorraine Moller, who placed fifth in the '84 Olympic marathon, and U.S. Olympic marathoner Julie Isphording from Cincinnati.