The day he won a race last month for the only time in his brief career as a jockey, Emanuel Jose Sanchez was so unsteady after crossing the finish line at Colonial Downs, he needed help guiding the horse into the winner's circle.

His fellow jockeys, as well as the racetrack stewards, warned the popular 22-year-old rider from Carolina, Puerto Rico, to be careful with how he lost weight, to eat right, to exercise more.

On Friday evening, after riding a horse named Bear On Tour in the fourth race at the New Kent, Va., track, Sanchez was found lying on the floor of the shower in the jockey's room. After being examined by paramedics and the track physician, the apprentice rider was transported to Bon Secours Community Hospital in Richmond.

Showing signs of dehydration, he reportedly lapsed into a coma en route and later died.

"He was a great person, a big heart," said journeyman rider Christian Olmo, 21, who grew up with Sanchez in Puerto Rico, took him into his home in Laurel during the Maryland racing season and had been rooming with him in a motel near Colonial Downs at the time of his death. "He was a hard worker. He got on a lot of horses in the morning. He just said, 'I want to work.' He said, 'I don't want to be the best, I just want to ride.' "

The jockeys at Colonial Downs gathered with the racetrack chaplain in the winner's circle yesterday before the first race for a brief memorial service and a moment of silence.

"They all liked him," Colonial Downs General Manager John Mooney said. "He was part of the colony here. They feel very badly. I don't think any of them realized how serious this might be. They certainly didn't when he" was taken to the hospital.

The Virginia medical examiner has not yet released a report on the official cause of death. Mooney declined to comment further, but Sanchez, by several accounts, had battled weight-loss issues that routinely haunt a jockey's life.

Depending on the conditions of a given race, a horse in Virginia can be assigned a weight of as few as 111 pounds. Sanchez, because of his relative inexperience, received an extra 10-pound weight allowance from other jockeys. On a horse a journeyman might ride carrying 118 pounds, Sanchez conceivably could go as low as 108.

Jockeys regularly struggle to lose weight in the sweat box and sometimes use diet pills and even regurgitate food.

The Jockeys Guild, a national non-profit collective bargaining organization that represents riders, has petitioned state racing commissions around the country this year to raise the jockey's weight scale to a minimum of 118 pounds, prohibit body fat levels of less than 5 percent and to offer nutritional programs to riders.

"We've been pushing hard to get the weights changed across the United States," said guild representative Larry Saumell, a former jockey on the Mid-Atlantic circuit. "You can't believe the outrageous excuses I get: 'If they're that big, they should find another sport.' "

Saumell said he visited Colonial Downs last week and met Sanchez for the first time. "I talked to him about joining up," he said. "He was kind of big, to be quite frank."

Sanchez primarily worked as an exercise rider at Bowie Training Center and other tracks. Before arriving at Colonial Downs, he had finished unplaced on 10 mounts at Pimlico and Delaware Park.

He had 14 mounts at Colonial Downs and rode his only winner June 19, a horse named Mark Me Special trained by Edward Kohlheim at the Bowie Training Center.

"He said, 'I'm going to win a race for you,' and he won a race," Kohlheim said yesterday after Mark Me Special finished second in a race at Charles Town, this time ridden by jockey Carlos Castro. "I'm proud he got a win under his belt, because that's what he said he wanted to do with his life."

Something was wrong with Sanchez that afternoon, however.

"When he pulled up after the race on the far turn, he was unstable," said Stan Bowker, a racing steward at Colonial Downs. "He needed help bringing the horse back to the winner's circle. He had trouble catching his breath. They took the picture in the winner's circle with him on the horse. After he weighed out, he needed to sit down and catch his breath before he could get a picture taken with the" winning owners.

The stewards called a meeting with Sanchez the following day. Officials in the jockeys' room reportedly had told them the rider had been overweight and spending a lot of time in the steam box.

Olmo said he constantly set a good example. "I always tried to tell him how to do things, how to lose weight, what he can eat and can't eat," the jockey said. "I always said, 'Eat salads. Eat a good diet. Don't drink soda.' "

The stewards told Sanchez he not only was jeopardizing himself but the rest of the riders, as well, if he fell off a horse in the middle of a race.

"He assured us that would not happen, and we didn't have any comments from anyone else down there since that situation," Bowker said.

The day he died, Sanchez rode at 114 pounds. He was scheduled to ride a horse named Gitem Willie in the final race on yesterday's card. Olmo substituted and finished seventh.

Sanchez, who according to Olmo is survived by a 6-year-old daughter, will be buried in Puerto Rico.