Mexican marathoner German Silva would like to repeat as winner of the New York City marathon. And he would like to run another fast time. To do both, he will have to stay on course.

Sounds simple.

But for Silva, who made a wrong turn with less than a mile to go in New York last year, staying on course is a personal challenge.

He has not forgotten that horrible feeling, when he realized he had taken a wrong turn and his lead had slipped away. And he also will never forget the effort it took to double back and regain the lead in a mad sprint that gave him the victory by a razor-thin two seconds. This year, he's not taking any chances. He's spent three weeks in New York, training and studying the course. "I know very well the course," he said.

Silva will be defending his title this Sunday, Nov. 12, as he and some 30,000 other runners traverse the patchwork of pavement and potholes that comprise New York's five boroughs.

Kenya's Tegla Loroupe will also attempt to repeat as victor of the women's race. Both runners expect tough competition.

On Wednesday, the 27-year-old Silva declared, "Yes, I am ready ... I even feel better than last year." Consistent weeks of running 220 to 230 kilometers--roughly 140 miles, and much of it at altitude--are the likely reason why. "The course we use for training, it is just up, up, up all the time," he remarked, describing his weekly ascent of--yes, it's true--a volcano.

He might as well be describing the meteoric rise of himself and his teammates on the international marathoning circuit.

Among the men, at least one Mexican runner has placed in the top five in New York for the past six years. In three of those years--'91, '93 and '94--three Mexicans took top honors. A marathon is a notoriously difficult event to predict, but suffice it to say that this Sunday there will be a strong showing from south of the border.

Isaac Garcia, 27; Jorge Marquez, 28 and Gumercindo Olmedo, 32, will round out the elite Mexican contingent. ("I think they are in good shape," Silva confided.) All have run 2:13 or better for the 26.2-mile race. Silva, whose winning time last year was 2:11:21, ran a 2:09:18 in the 1994 London race. (The world best for the marathon is 2:06:50; the New York course record is 2:08:01.)

But this is truly anybody's race. There are seven sub-2:10 performers entered, another 10 under 2:11--in all, almost 40 entrants who have reached 2:13 or better. Portugal's Manuel Matias is the fastest of the bunch, with a lifetime best of 2:08:33. Last December, Matias broke 2:10 for the fourth time, running 2:09:50 to place second at Japan's Fukuoka race.

The sentimental favorite would have to be South Africa's Gert Thys, who will turn 24 on race day. In 1993, Thys ran a remarkable 2:09:31.

And for grit and determination, watch Salvatore Bettiol of Italy. In 1988, Bettiol battled a severe hamstring cramp to finish second in New York. The next year, he came back to place fourth. Last year, he notched a career mark of 2:09:40 in London. In all but one of his 22 career marathons, the resilient Bettiol has finished in the top 10.

As is usual on the American road scene, a large contingent of Kenyans will compete. Although Kenyans have twice won here, they have not been as dominant in New York as they seem to be elsewhere around the world. Notwithstanding, don't be surprised to see a Kenyan in the lead--especially in the women's race.

After a spectacular win in New York last year, Kenya's Tegla Loroupe remarked, "I think if I'd started with the others, I would have improved my time." Loroupe is referring to the fact that she ran a slow first half last year, and only took the lead after 19 miles. Not that 2:27:37--second fastest debut ever, and over two minutes ahead of the second-place runner-- especially needed improvement. (The world mark for women is 2:21:06; in New York, it's 2:24:40.)

However, there will be more than enough women to push the pace. Loroupe herself remarked, "Machado is there and Olga Appell, so I think the race will be competitive."

Competitive, indeed. Portugal's Manuela Machado poses the greatest threat to Loroupe, as shown by her convincing victory at the 1995 World Championships in Sweden. A consistent 2:27 performer, Machado will be running her 19th marathon.

Olga Appell, formerly of Mexico, is a prime contender for the United States, as she now makes her home in Albuquerque, New Mexico. Appell won the 1994 Los Angeles Marathon in a career best of 2:28:12.

Of course, don't count out Madina Biktagirova of Belarus who, with a lifetime best of 2:26:23, is the fastest entrant in the field. Brazil's Carmen De Oliveira, Finland's Tuija Toivonen and Estonia's Jane Salumae round out the sub-2:30 crowd.

Loroupe will certainly be in good company. Asked if she would start faster this year, she cleanly sidestepped the question: "I'll run according to the time I've prepared." But it didn't take much cajoling to get what she was really thinking. "OK, maybe I will start a little faster," she conceded.

Whatever their pace, Loroupe, Silva, and 30,000 others will leave the Staten Island starting line at 10:50 a.m.