Here is the perception: female jockeys can’t ride. They’re too weak. They don’t have the fight in them. They can’t close — not like men, anyway. Down the stretch, you need a jockey to carry the horse to the end, rally the winded animal and squeeze speed out of weary legs. Female jockeys can’t do that. Or so goes the explanation for why, almost 50 years after women first fought legal battles to become jockeys, there are so few top jockeys who are women.

Then there’s Rosie Napravnik.

The 113-pound New Jersey native isn’t just the most successful “girl jockey” on the horse-racing circuit today; she’s one of the best American jockeys, period. Last year, she amassed more than $12.4 million in earnings, eighth-best in North America. Her horses finished in the top three in nearly half the races she entered. So far this year, she ranks fifth in earnings, leads all jockeys in victories and has picked up her third consecutive riding title at the New Orleans Fair Grounds Race Course.

Some of her male competitors are less than charitable about the reasons for Napravnik’s success. “Look at me,” a veteran jockey was saying before a race in New Orleans last month. “I’m 53 years old, brother. I’m going to walk into a paddock, and I’m going to talk to these owners and their wives and stuff. And there’s little Rosie. She’s going to bounce out of there. A pretty little girl, good disposition. And she’s going to be talking all nice to them. Now, which one of them would you rather leg up on your horse?”

But Todd Pletcher, one of the nation’s leading trainers, speaks for a lot of his peers when he says: “I don’t really think of Rosie as a girl jockey. She’s just a good jockey.”

Pletcher was responsible for one of Napravnik’s biggest breaks yet when, in the spring of 2012, he needed a jockey for a 2-year-old horse named Shanghai Bobby in its first career race and gave her the mount. In the race, at Aqueduct in New York, horse and rider broke more slowly than the others out of the gate, but after they turned for home, wide off the rail in third place, Napravnik asked the horse for more, and Shanghai Bobby surged to the front. In the end, it wasn’t even close.

Napravnik and Shanghai Bobby continued to win, finishing first in all five of their starts in 2012, including the $2 million Breeders’ Cup Juvenile in November. Napravnik seemed certain to ride Shanghai Bobby in the Kentucky Derby next month and be one of the favorites at an event no woman has ever won. Napravnik tried to ignore the hype. “You have to keep winning,” she told me. “The moment you stop winning or get into a slow period, people completely forget about you.”

And then, she and Shanghai Bobby stopped winning. Second and fifth place finishes in January and March put an end to the horse’s Kentucky Derby prospects. But not to Napravnik’s: in mid-April she accepted an offer to ride another, already-qualified horse in the Derby, Mylute.

After all, there are not many people, male or female, who can do what she does. Napravnik knows exactly where she needs to be on the track, trainers say, possessing a keen sense of pace. And she’s not easily intimidated. Larry Jones, the trainer who won the Kentucky Oaks last year with Napravnik riding a horse named Believe You Can, says he has seen other jockeys intentionally bump her during a race. “Trust me,” he says. “Don’t do Rosie that way, because she will run over you. The girl has no fear.”

Trainers also say she has some of the softest hands in the business, and few things are more essential to a jockey — relaxed hands tell a horse that it’s not yet time to go. Horses just seem to listen to her. “Rosie can take a really high-strung horse, and he’ll settle down for her,” one trainer says. “That’s an inherent gift that she has.”

No doubt it comes in part from growing up with a mother who trained event horses in Bedminster, N.J., and a father who works as a farrier, tending to horses’ hooves. Napravnik was racing at 7; at 16, she was exercising horses at Pimlico Race Course in Baltimore, where a trainer named Holly Robinson was impressed by this “tough, little redheaded girl” who said she wanted to win the Triple Crown.

Now, at 25, she is one of the more provocative figures in racing, heckled at times by critics who don’t think she belongs on the track while being asked for her autograph by fans.

At a small-time race in New Orleans in December, Sturges Ducoing, a trainer, asked Napravnik to ride an unheralded horse, with one victory to its name. It’s the sort of grunt work that all jockeys must do. The horse finished second, a result that thrilled Ducoing. “We didn’t even belong in this race,” he told Napravnik afterward. Then he asked a favor: could she autograph five pairs of goggles for him to give to some children with his party at the track that day? “Here,” he said. “I’ll give you some money.” She refused it. “Thank you, baby,” Ducoing said. “I’m sorry we didn’t win.”

Napravnik just smiled. “Don’t worry about it,” she said.