RUIDOSO, N.M. — At 2:11 p.m., as two ambulances waited with motors running, 10 horses burst from the starting gate at Ruidoso Downs Race Track 6,900 feet up in New Mexico’s Sacramento Mountains.

Nineteen seconds later, under a brilliant blue sky, a national champion jockey named Jacky Martin lay sprawled in the furrowed dirt just past the finish line, paralyzed, his neck broken in three places. On the ground next to him, his frightened horse, leg broken and chest heaving, was minutes away from being euthanized on the track.

For finishing fourth on this early September day last year, Jacky Martin got about $60 and possibly a lifetime tethered to a respirator.

The next day, it nearly happened again. At virtually the same spot, another horse broke a front leg, pitching his rider headfirst into the ground. The jockey escaped serious injury, but not the 2-year-old horse, Teller All Gone. He was euthanized, and then dumped near an old toilet in a junkyard a short walk from where he had been sold at auction the previous year.

In the next 24 hours, two fearful jockeys refused their assigned mounts. The track honored two other riders who had died racing. As doctors fought to save Mr. Martin’s life, a sign went up next to the track tote board: “Hang in there, Jacky. We love you.”

On average, 24 horses die each week at racetracks across America. Many are inexpensive horses racing with little regulatory protection in pursuit of bigger and bigger prizes. These deaths often go unexamined, the bodies shipped to rendering plants and landfills rather than to pathologists who might have discovered why the horses broke down.

In 2008, after a Kentucky Derby horse, Eight Belles, broke two ankles on national television and was euthanized, Congress extracted promises from the racing industry to make its sport safer. While safety measures like bans on anabolic steroids have been enacted, assessing their impact has been difficult because many tracks do not keep accurate accident figures or will not release them.

But an investigation by The New York Times has found that industry practices continue to put animal and rider at risk. A computer analysis of data from more than 150,000 races, along with injury reports, drug test results and interviews, shows an industry still mired in a culture of drugs and lax regulation and a fatal breakdown rate that remains far worse than in most of the world.

If anything, the new economics of racing are making an always-dangerous game even more so. Faced with a steep loss of customers, racetracks have increasingly added casino gambling to their operations, resulting in higher purses but also providing an incentive for trainers to race unfit horses. At Aqueduct Racetrack in Queens, the number of dead and injured horses has risen sharply since a casino opened there late last year.

Mr. Martin’s injury occurred in a state with the worst safety record for racetracks, a place where most trainers who illegally pump sore horses full of painkillers to mask injury — and then race them — are neither fined nor suspended and owners of those drugged horses usually keep their winnings.

The failure of regulators to stop that cheating is reflected in the numbers. Since 2009, records show, trainers at United States tracks have been caught illegally drugging horses 3,800 times, a figure that vastly understates the problem because only a small percentage of horses are actually tested.

In the same period, according to the Times analysis, 6,600 horses broke down or showed signs of injury. Since 2009, the incident rate has not only failed to go down, it has risen slightly.

The greatest number of incidents on a single day — 23 — occurred last year on the most celebrated day of racing in America, the running of the Kentucky Derby. One Derby horse fractured a leg, as did a horse in the previous race at Churchill Downs. All told, seven jockeys at other tracks were thrown to the ground after their horses broke down.

A state-by-state survey by The Times shows that about 3,600 horses died racing or training at state-regulated tracks over the last three years.

In one 13-day stretch of racing in 2010 at Sunland Park Racetrack and Casino in New Mexico, nine horses died racing, five were hauled away in ambulances and two jockeys were hospitalized, one in critical condition.

“It’s hard to justify how many horses we go through,” said Dr. Rick Arthur, the equine medical director for the California Racing Board. “In humans you never see someone snap their leg off running in the Olympics. But you see it in horse racing.”

Even some of America’s most prestigious tracks, including Belmont Park, Santa Anita Park and Saratoga Race Course, had incident rates higher than the national average last year, records show.

Why racehorses break down at such a high rate has been debated for years, but the discussion inevitably comes back to drugs.

Laboratories cannot yet detect the newest performance-enhancing drugs, while trainers experiment with anything that might give them an edge, including chemicals that bulk up pigs and cattle before slaughter, cobra venom, Viagra, blood doping agents, stimulants and cancer drugs.

Illegal doping, racing officials say, often occurs on private farms before horses are shipped to the track. Few states can legally test horses there.

“They are pharmacist shops,” said Dr. George Maylin, the longtime head of New York State’s testing laboratory. “Nobody has any control over what they are doing.”

Even so, legal therapeutic drugs — pain medicine in particular — pose the greatest risk to horse and rider. In England, where breakdown rates are half of what they are in the United States, horses may not race on any drugs.

At higher levels, pain medicine can mask injury, rendering prerace examinations less effective. If a horse cannot feel an existing injury, it may run harder than it otherwise would, putting extra stress on the injury. As many as 90 percent of horses that break down had pre-existing injuries, California researchers have found.

“This is just a recipe for disaster,” said Dr. Tom David, who until this year was chief veterinarian for the Louisiana Racing Commission. “Inflamed joints, muscles and mild lameness are masked by medication and therefore undetectable to the examining veterinarian.”

While high-profile Triple Crown races get the most attention, the mainstay of racing in America is the lower tier, so-called claiming races. Horses in these races are most vulnerable, in part because regulators often give them less protection from potentially dangerous drugs.

The Times analysis found that horses in claiming races have a 22 percent greater chance of breaking down or showing signs of injury than horses in higher grade races. That lower level of race has been particularly affected by the arrival of casinos.

At Aqueduct, most of the 16 horses that have died so far this year were in the lower ranks, where purses have increased the fastest because of new casino money.

“It’s hard to watch these poor animals running for their lives for people who could really care less if they live,” said Dr. Margaret Ohlinger, a track veterinarian at Finger Lakes Casino and Racetrack in upstate New York. She performs pre-race inspections and treats horses injured in races but is not responsible for their overall care.

Last year at the track, Dr. Ohlinger counted 63 dead horses. That, she said, is more than double the fatalities of five years earlier.

Oversight Undermined

Race officials have always done their best to hide fatal breakdowns, erecting screens around fallen horses and then refusing to disclose the tracks’ accident rates.

But amid criticism that individual state racing commissions lacked the will to make the sport safer, and the threat of federal oversight, the industry promised changes, including new restrictions on the use of drugs, a program to accredit racetracks and drug-testing laboratories and uniform rules for punishing drug violators.

The industry also set up a national database where tracks were asked, but not required, to report injuries with the promise of confidentiality.

So far, the response to these reform measures has fallen short.

Fifty-five tracks pledged that they would seek accreditation, requiring among other things prerace inspections and postmortem examinations, or necropsies. Fewer than half have kept their promise.

“Some tracks do not have the money to spend to meet our standards; others think it’s window dressing and why bother,” said Michael Ziegler, executive director of the National Thoroughbred Racing Association Safety and Integrity Alliance. “Any follow-up with tracks has gone unanswered.”

The laboratory accreditation program, introduced in July 2009, has fared even worse. After calling the program an “unprecedented” step that “ultimately will change the face of drug testing in this country,” a consortium of industry groups that manages it says not a single lab has been accredited.

An association of racing regulators wrote to Congress on May 14, 2010, boasting that with the exception of anti-bleeding medicine, “race day medications are not allowed.” Yet records show that in Florida, a major racing state, trainers continue to use corticosteroids, an anti-inflammatory, on race day.

The national repository for injury reports, maintained by the Jockey Club, the most powerful racing industry group, has been more successful, gathering data from 92 percent of the racing days.

“We put it into a database, and we provide tools back to the racetracks where they can analyze and slice and dice the information themselves,” said James L. Gagliano, president of the Jockey Club, who says the group has encouraged racetracks to make the statistics public. So far, 24 out of 86 tracks have done so.

To assess how often horses get injured, The Times bought data for about 150,000 races from 2009 through 2011, then searched for terms indicating that a horse encountered a physical problem, like “broke down,” “lame” or “vanned off.”

Although the people who chronicle the races, known as chart callers, can be stylistically different, they are taught to use standard industry terms, and their descriptions constitute the official record used by gamblers to evaluate horses.

The analysis showed that during those three years the rate of incidents for horses in the United States was 5.2 per 1,000 starts.

By contrast, Woodbine Racetrack in Toronto, which year after year has one of the lowest breakdown rates in North America, had an incident rate of only 1.4, according to the Times analysis. “One of the differences here is medication is not as permissive as it is in the U.S.,” said Jamie Martin, executive vice president of racing at Woodbine.

According to the analysis, five of the six tracks with the highest incident rates last year were in New Mexico. All are casino tracks, commonly called “racinos.” Ruidoso, where Jacky Martin was injured, topped the list in 2011 with 14.1 incidents per 1,000 starts. Ruidoso attributes its incident rate in part to the failure of horses to acclimate quickly to the track’s elevation. Some horses that appeared to be injured, track officials said, may have simply needed time “to catch their breath.”

Yet no accident over the last three years can match what occurred in a single race on Feb. 29, at Hollywood Casino at Charles Town Races in West Virginia. Eight horses started. Seven fell. One finished. Along the way, seven jockeys were left scattered on the ground.

The next and final race was canceled, not just because it took so long to clear the track, but also because too few jockeys were available or willing to ride.

Drug Violations

It was the day’s first race in Hobbs, N.M. The track was fast and the weather clear. Shortly after noon on Oct. 16, 2010, nine young horses were loaded into the starting gate at Zia Park Casino.

With the finish line a mere 400 yards away, this would be an all-out sprint, horse racing’s equivalent of a drag race. While these races, run by a breed called quarter horses, lack the ebb-and-flow suspense of a longer thoroughbred race, they make up for it in a pure adrenalin rush. The best quarter horses can hit nearly 50 miles an hour.

Three weeks earlier at Zia Park, Mark Anthony Villa was on the back of a quarter horse when it fell just past the finish line, throwing him to the ground. With a herd of thousand-plus-pound animals bearing down on him, Mr. Villa tried to crawl to safety.

He never made it. A horse’s hoof struck him in the head with such force that his helmet shot like a bullet across the track. He died within an instant, leaving a wife and twin children.

For years, track veterans could only speculate as to whether racing quarter horses was more dangerous than racing thoroughbreds. In fact, the Times analysis shows that quarter horses have a nearly 29 percent greater chance of breaking down or showing signs of injury.

With Mr. Villa’s death still on the minds of riders and spectators, a gray 2-year-old colt named I Glance at Chicks settled in the 6 hole waiting for the starting bell. For bettors, he was an animal to watch. The horse had won his only race and was trained by Andres Gonzalez, who, according to racing commission records, was not above allowing his horses to race with extra help. Illegal help.

A week earlier, another horse trained by Mr. Gonzalez had raced at Zia Park with 12 times the legal limit of a drug that mimicked steroids. By the end of 2011, Mr. Gonzalez would have amassed a dozen drug violations in just four years. His uncle, Ramon O. Gonzalez Sr., for whom he often worked, had his own lengthy list of violations, including accusations that he drugged 10 horses in just two months.

Whether I Glance at Chicks felt pain as he raced is unknown, but he never challenged for the lead. Shortly after crossing the finish line in fifth place, he broke down. The diagnosis: a bone fracture in his front left leg and ligament damage, injuries from which he could not recover.

A veterinarian, Dr. Clayton McCook, euthanized the colt with an injection of pentobarbital. Afterward, Dr. McCook wrote a note “to whom it may concern,” expressing his distress to the authorities over this fatal breakdown and others like it.

“I have had to euthanize several horses due to catastrophic injuries and feel they are occurring in greater numbers than one should expect,” Dr. McCook wrote. “I do not pretend to be an expert in racing surfaces, nor in the training of racehorses, but I do know that something appears to be amiss at Zia Park.”

According to an analysis of race records, Zia Park in 2010 had the nation’s second-highest incident rate, 13.3. Last year, it ranked fourth with a rate of 11.9. After horse owners complained about the track surface, Zia Park officials said they spent $80,000 resurfacing it before the 2011 racing season.

During the three days that a Times reporter visited Zia Park last November, eight horses collapsed, died or were transported off the track. At the time, track officials said it was company policy not to allow a reporter access to the backside where trainers stable their horses.

Christopher McErlean, vice president of racing at Penn National Gaming, which owns Zia Park, said in a statement that the Times analysis used figures “produced by nonmedical professionals for the purpose of handicapping feature races.”

Mr. McErlean also said some horses are vanned off as a precaution and may not actually have been injured.

But Zia Park officials said that last year, “a significant number” of horses had to be carried off the track because of exhaustion stemming from the possible abuse of a drug that mimics anabolic steroids as well as “other medication issues.”

Mr. McErlean said Penn Gaming endorses tougher penalties for those who violate drug rules.

Without a postmortem exam of I Glance at Chicks, no determination could be made as to whether a pre-existing condition or some other unknown factor might have played a role in his demise. But tests did reveal that the horse had been dosed with a large load of a powerful painkilling medicine called Flunixin.

In at least two states, 2-year-olds may not race with any Flunixin. Not so in New Mexico, where they can run with up to 50 nanograms of the drug, more than double the amount allowed in a higher class of competition called graded stakes races.

But even that higher amount was not enough for Mr. Gonzalez. I Glance at Chicks carried 282 nanograms of Flunixin.

To put that figure in perspective, Dr. Mary Scollay, chief veterinarian for the Kentucky Racing Commission, said she had never seen such high levels in her state.

“When you look at the history of our medication violations — Flunixin — most are under 50 nanograms, 35 nanograms, something like that,” Dr. Scollay said. In fact, she said she had never seen a violation in Kentucky over 104.

In New Mexico, it is common practice.

Tests on horses in New Mexico showed results over 104 nanograms on 68 occasions since 2009, with some registering 1,000 and even 2,400, records show. The levels are so high that regulatory veterinarians in other states say the horses must have been drugged on race day, a practice that is forbidden.

Before the New Mexico Racing Commission could pass judgment on the overdosing of I Glance at Chicks, another horse trained by Mr. Gonzalez tested positive for even higher levels of Flunixin. The extra dosing did not hurt performance. The horse finished first, and its owner, Mr. Gonzalez’s cousin Ramon Gonzalez Jr., got to keep his winnings.

If Andres Gonzalez was worried about how the racing commission viewed his treatment of I Glance at Chicks, he need not have been. Records show he received a warning and nothing more.

Lax Penalties

New Mexico’s racing industry — the tracks and their regulators — has been unusually slow in responding to the safety alarms.

Four of the state’s five racetracks, including Zia Park and Ruidoso, are unaccredited, and the track where Mr. Martin’s injury occurred does not report accidents or positive drug tests to groups that monitor such events.

New Mexico also recorded no positive tests in 2010 and 2011 for the most frequently abused pain medicine in racing, phenylbutazone, a nonsteroidal anti-inflammatory commonly known as “bute.” After The Times asked why none had been found, the new executive director of the state’s racing commission, Vince Mares, said that after researching the question, he discovered that the previous leadership “had cut back on the tests” for financial reasons.

Without a national law regulating drugs in racing, New Mexico regulators can be as lenient as they wish in disciplining drug violators.

Trainers in New Mexico who overmedicate horses with Flunixin get a free pass on their first violation, a $200 fine on the second and a $400 fine on the third, records show.

In Indiana, by contrast, winnings are forfeited after the first drug offense. “If someone who violates the rule thinks the penalties are going to be mild or nonexistent, then breaking the rules is just a cost of doing business,” said Joe Gorajec, the executive director of the Indiana Horse Racing Commission.

New Mexico gives offenders another break: it wipes away Flunixin violations every 12 months, allowing trainers to again overmedicate horses without penalty. Dozens of huge Flunixin overdoses have resulted in warnings only.

Sometimes the same horse is illegally drugged twice. On May 9, 2009, Runawayslew, a horse trained by Andres Gonzalez, raced with two anti-inflammatory drugs. Nineteen days later, under another trainer, Runawayslew raced on cocaine.

To varying degrees, the picture is similar nationwide. Trainers often face little punishment for drug violations, and on the rare occasions when they are suspended, they are allowed to turn their stables over to an assistant. Since January 2005, 116 trainers have had five or more drug violations, and 10 trainers had 10 or more, records show.

In New Mexico, Cody Kelley, an Albuquerque lawyer who represents people accused of violating racing commission rules, including Andres Gonzalez, said punishments were too arbitrary.

“Are there people that cheat at horse racing in New Mexico? Yes, happens everywhere,” Mr. Kelley said. “But I think our commission right now is not equipped to deal with it. What we need are national rules.”

Mr. Mares, the New Mexico racing chief, agrees that his agency needs more uniform penalties to avoid charges of favoritism. “There is an issue of consistency — you can quote me on this,” Mr. Mares said. “It is being addressed.”

New Mexico recently became the first state to temporarily ban all horses from racing on clenbuterol, a drug that aids respiration, but that has been widely abused because it can build muscle.

In recent years, the state commission has had its embarrassments.

One former investigator faces trial on charges of stealing horses while working at the commission. Another trainer’s doping violation was dismissed because the assistant attorney general handling the case neglected to show up in court. And the commission had to drop charges against Ramon O. Gonzalez Sr. for drugging 10 horses because it forgot to file the proper paperwork, according to the state attorney general’s office.

Nonetheless, odds are slim that any of the Gonzalezes — Andres, Ramon Sr. or Ramon Jr. — will show up at a New Mexico racetrack any time soon. In late January, a federal grand jury in Albuquerque indicted them on charges of participating in a drug trafficking scheme tied to one of Mexico’s most notorious drug cartels. All have pleaded not guilty.

Andres Gonzalez was arrested at Sunland Park Racetrack and Casino in New Mexico. His uncle, Ramon Sr., was arrested while pulling a horse trailer that the authorities said was carrying 26 kilograms of cocaine and 500 pounds of marijuana.

Masking Pain, or Healing It

Breakdowns can be caused by a variety of factors, including poor track surface and jockey mistakes. But drugs, often used to mask existing injuries, are the prime suspect.

“It’s not that these medications caused the injuries, but the trainers knew the horses were injured and gave them the meds to get them into the race,” said Dr. Arthur, the veterinarian for the California Horse Racing Board.

Necropsies are considered essential to determining if an existing injury contributed to a fatal breakdown. However, only 11 states require them, a Times survey found.

In California, where necropsies are required, researchers found that a “large majority” of horses had existing problems at the site of their fatal injuries.

“To be fair, some of that is microscopic and may not be readily apparent,” Dr. Arthur said. “We’re trying to figure out why vets and trainers are not identifying injuries prior to catastrophic injuries.”

But many prior ailments are indeed serious. The Times obtained hundreds of necropsy reports on racehorses that died racing in Pennsylvania and found problems that included “severe degenerative joint disease,” “severe chronic osteoarthritis” and pneumonia with “severe, extensive” lung inflammation. One horse had 50 stomach ulcers. Another had just one eye. Pathologists also found metal screws in two horses that had broken bones from previous accidents.

In the United States, horses are usually allowed to run on some dose of pain medication, usually bute. The question, fiercely debated in the racing community, is at what level do therapeutic drugs make racing unsafe?

Virginia’s fatality rate went up after regulators in 2005 raised the allowable level of bute to 5 micrograms from 2 micrograms. “Our catastrophic incidents increased significantly,” said Dr. Richard Harden, equine medical director for the state racing commission.

Virginia returned to the lower level in 2009, though the fatality rate has not come down.

Iowa’s fatality rate rose by more than 50 percent after the state in 2007 allowed a higher level of bute.

Regulatory veterinarians say the higher allowable levels make it difficult for them to spot lameness and injury during prerace examinations. In one study, researchers at Oklahoma State University said they found bute in most of the horses that died racing or training at Oklahoma tracks in 2010. Six had both bute and Flunixin, a dangerous practice called “stacking,” the report said.

The researchers also expressed concern that despite fewer races, a record number of horses died, necessitating a “careful re-evaluation of track surfaces, medication/enforcement and prerace examinations.”

But prominent owners and trainers, and even some veterinarians, say evidence linking drugs and breakdowns is unconvincing.

Kent H. Stirling, chairman of the national medication committee for the Horsemen’s Benevolent and Protective Association, said there was “no scientific evidence whatsoever” that 5 micrograms of bute on race day is dangerous.

Mr. Stirling and others say sore horses should not be denied therapeutic medicine when needed. “If you’re a horseman and you’re trying to keep a horse going and keep him happy and healthy as you can, then these therapeutic medications are very helpful,” he said.

Regulators typically view prescription drug violations as more benign than the use of banned substances on horses. And they constitute the bulk of the 3,800 violations that The Times found by surveying racing states.

But others, including racing regulators overseas, say horses should not compete on any drug regardless of type.

“Therapeutic drugs, by definition, are used for healing and curing,” said Arthur B. Hancock III, whose farm produced three Kentucky Derby winners. “Drugs that mask pain and enhance performance are not ‘therapeutic.’ They are what they are: performance-enhancing drugs.”

The industry group that runs graded stakes races had promised to ban all therapeutic drugs for 2-year-olds, but in late February backed off, saying it did not have enough time to bring state regulators on board.

George W. Strawbridge Jr., a prominent breeder and owner, resigned from the group over that decision, calling it “one of the most craven acts” he had seen.

“How on earth did we get to this sorry state?” Mr. Strawbridge said. “The first reason is that in this country there are no significant consequences for doping horses.”

Respecting the Ride

Chris Zamora knows the sensation of riding a sore horse. But one ride in particular stands out.

On Nov. 25, 2008, Mr. Zamora was guiding his horse, Sinful Heart, into the first turn at Zia Park when he sensed something was wrong. “He didn’t want to take the turn,” he said. “He was in pain.”

Sinful Heart drifted out, clipped heels with another horse and fell. A trailing horse tripped over them.

Mr. Zamora, the winner of more than 1,000 races, nearly died in the accident, fracturing his skull, pelvis, ribs and four vertebrae. His lungs collapsed, his liver was lacerated and his heart was compressed. “They had to insert a needle to take the pressure off of my heart,” he said.

Sinful Heart survived to race three more times, in successively cheaper races, never winning before collapsing and dying on the track at Ruidoso.

Four months after his accident, in March 2009, Mr. Zamora returned to the track. But he had changed. No more cheap horses. “I tried to ride quality over quantity,” he said. “I didn’t ride a horse that somebody said was already sore. I scratched more of them at that time than I had in my whole life.”

The best trainers might have been unhappy, he said, but they trusted his judgment and fixed the problem. “They were great horsemen,” Mr. Zamora said, offering the ultimate compliment.

But not all were. Now, he said, some trainers just go to another rider. “These guys will head a horse up until it breaks down completely, and when there’s a man on top of them, it’s bad,” he said.

Other injured jockeys tell similar stories. “I think more should be done for the horse to let him heal naturally than to be getting him to the next race so we can get one more race out of him,” said Randy Meier, a winner of more than 4,000 races, many in the Chicago area.

Along the way, Mr. Meier broke his neck, collarbones, ribs, shoulder, legs, arms, wrist and sternum and developed a brain bleed.

New Mexico jockeys have been hit particularly hard. Not only was Mr. Villa killed and Mr. Zamora and Mr. Martin critically injured, Juan Campos died in an accident in August 2008; Jimmy Ray Coates fell the same year, his heart stopping twice after breaking his femur, shoulder and collarbone; Carlos Rivas had no pulse en route to the hospital after rupturing his aorta in 2010, and the same year Kelsi Purcell fractured multiple vertebrae in a spill.

There were other injuries as well.

“We’ve been through this so many times,” said Terry Meyocks, national manager of the Jockeys’ Guild. More than 50 permanently disabled jockeys receive assistance from the Jockeys’ Guild, he said.

After Mr. Zamora’s accident, Mr. Martin, a friend and hunting partner, had told him not to abandon hope. “You’ll be back,” he said. “You’re in great shape, it won’t be that long. You’re not done. You won’t be in a walker.”

Like all jockeys, Mr. Zamora knew the risks of riding. “Every time you do it, you take a chance one is going to break it off. Even with the soundest horse you take a chance.”

Good jockeys can alter their ride if a horse is sore or about to break down. In some cases, though, there are no hints, no warnings. And that is when jockeys face the greatest danger.

Jacky Martin had no warning.

“I thought he was going to die,” said Adrian A. Ramos, who was riding in the same race. “He hit the ground hard, real hard. I was behind him and I saw everything.”

A Second Chance

The question almost everyone at the track wanted to ask was why. Why did Mr. Martin, at the top of his game, the winner of a record seven All American Futurities, agree to ride a cheap claiming horse with no victories just three days before he was to ride the favorite in the $2.4 million Futurity?

The favorite did eventually win and would have paid him $120,000, the jockey’s standard share. For riding the horse that broke his neck, Mr. Martin took home little more than the cost of a tank of gas.

Until that wrenching moment in the Ruidoso dirt, Mr. Martin at age 56 had been on a redemptive journey to right the wrongs in his life, to help younger jockeys avoid the mistakes he had made and to regain what he had lost: an opportunity to sit atop a racehorse and to coax from it all the power it was willing to give, and nothing more.

For four years, Mr. Martin had been barred from racing after being sentenced to probation in 2006 for poaching deer and possessing less than a gram of methamphetamine. He and his wife, Tracey, also his agent, moved to Louisiana. “I worked horses every day for three and a half years being a gallop boy,” Mr. Martin said. “That’s all I was, a $10 gallop boy.”

In the afternoon, Mr. Martin helped to build fences and even a barn, his wife recounted. “We actually bagged horse manure and sold it and delivered it just to get through,” she said.

It was a steep fall for a man so highly revered in the sport that Mexican businessmen would send armed guards to escort him to high-stakes races south of the border.

“After a time, he took ownership for the wrong things that he did and worked his way through it,” Ms. Martin said. Just as important, friends say, he developed an even deeper appreciation for the role others played in racing, from grooms to horse owners struggling to stay in the game.

In the summer of 2010, Mr. Martin was finally cleared to race, and he returned to Ruidoso unsure of how he would be received. When word spread that “Jacky was back,” owners were eager to extend a helping hand, but most of all, they were eager to win.

And win he did. With the racing season half over, Mr. Martin stormed into the lead to become the top winner and champion jockey for 2010.

“He was so grateful he got a second chance,” Ms. Martin said in December. “He was on the radio saying: ‘People out there need to know that they can be forgiven and succeed. If I can fix my screwed up life, you can too.’ ”

In Mr. Martin’s quest to win an eighth Futurity in 2010, his horse lost by a nose in one of the biggest upsets in the history of that race. But the loss did not diminish the joy he felt competing again.

“It’s just a fairy tale for it to turn out the way it has,” Mr. Martin told a racing publication in 2010.

Mr. Martin fell a year later, on the Friday before Labor Day at the beginning of the final, biggest weekend of racing at Ruidoso. The tens of thousands of spectators, who would later fill the stands and line the distant highway with parked cars, had yet to arrive.

Only a small, quiet crowd, including relatives of riders, trainers and owners, was on hand to watch Mr. Martin go down. One woman screamed because she mistakenly thought her husband had been the one injured.

The authorities did little to determine why Mr. Martin’s horse, Phire Power, broke down. The commission said drug tests found no prohibited substances, but the scope of those tests is unclear, including whether the horse was tested for bute. The state also said the horse’s body did not undergo any postmortem exam before it was destroyed.

Within minutes, Ms. Martin was escorted onto the track to be with her fallen husband. Over the next six months, she would rarely leave his side.

In two days, Mr. Martin had been scheduled to sign autographs at Ruidoso to raise money for injured jockeys. Instead, other jockeys signed autographs to raise money for him.

Since the accident, Mr. Martin has been in and out of hospitals in three cities. He has suffered through infections, pneumonia, nausea, weight loss, bed sores and other problems. He remains paralyzed, unable to move his arms or legs. He breathes with a respirator.

Meanwhile, the racing community has rallied to his side, sending not only words of support but also money to help defray his mounting health care costs. Ruidoso’s owner, R. D. Hubbard, promised $100,000. There have been silent auctions and other fund-raisers. His wife worries that it may not be enough.

Through it all, Mr. Martin refuses to feel sorry for himself.

In December, as he struggled to breathe in a Houston hospital, he told a reporter softly that he had no regrets.

“It’s a bad deal,” he said. “But if I could do it again, I would be right out there doing it. I ride horses. It’s the risk every jockey takes.”

Back home in El Paso, Ms. Martin says her husband derives one of his few pleasures from sitting in his wheelchair next to a window watching horses train silently in the distance.

Mr. Martin’s injury deeply affected Mr. Zamora. He was not only losing a friend from the jock’s room, the sport was losing a rider, a gentleman, who had come to represent the best it had to offer.

“He rode the best horses in the world, but he was worthy of the best horses in the world,” Mr. Zamora said. “He had great hands. He let a runner be a runner instead of going to the whip too early. Them animals loved him, and they ran for him and he understood them. When one didn’t want to run, he let ’em not run. He didn’t take to the whip. You have to understand them — that’s what makes a great horseman. And he was. He was special.”

Last fall, several weeks after Mr. Martin’s spill, Mr. Zamora left the jock’s room for the last time.

“I knew I had come so close, and I couldn’t deal with that.”

Pain, Up Close

It was the third race at Ruidoso on July 11, 2009.

In the stands, Laura and Armando Alvarado sat with their two grandchildren, ages 11 and 14.

The Alvarados were not racing fans, but this was a vacation — they had driven up to the mountain resort from El Paso — and they thought their grandchildren might enjoy watching their first horse race.

Mr. Alvarado took the children down to the rail for a closer look. Ten horses sprinted out of the gate, including a gray Texas-bred quarter horse named Sinful Heart, the same horse that fell several months earlier, nearly killing Chris Zamora.

Just past the finish line, Sinful Heart, with another rider on its back, broke down, collapsing on the track. “The horse is bleeding!” one of the children cried out.

The children were not visibly shaken, but Ms. Alvarado said she was sorry they had to witness death at such a close range. After a few more races, they went shopping.

Five days later, a relative with a passion for racing was visiting the Alvarados, and they all went to the track.

“It was going to be an all-day experience, and I thought how nice to have this man give them all this history and details,” Ms. Alvarado said.

Once again, Mr. Alvarado took the children to the rail to watch the finish of the day’s first race.

This time, a horse broke its leg, pitching its rider — who happened to be Chris Zamora — into the ground, where rider and animal rolled like tumbleweeds across the finish line.

“It was awful,” Mr. Alvarado said. Although Mr. Zamora was not seriously injured, the horse was. “The bone was showing through the skin,” Mr. Alvarado said.

Both children began to cry. “I have never seen anything that horrible close up,” Mr. Alvarado said. “The kids were terrified.”

The horse was euthanized on the track. The family quickly left the premises. Ms. Alvarado said: “I told Armando, just drive. We wanted to get out of there.”

Afterward, her granddaughter said, “I don’t want to go to a racetrack ever again.”

Ms. Alvarado wrote a letter to the editor of the local paper.

“For the sake of the animals and children, we felt compelled to let city officials, agencies and others know of this painful experience and urge you to investigate,” she wrote.

She said she sent copies of the letter to the mayor, the track, its chief veterinarian, the Humane Society and the American Society for the Prevention of Cruelty to Animals.

Ms. Alvarado expected a response.

She never got one, she said.

Rebecca R. Ruiz and Matthew Orr contributed reporting from New York.