Lorna Chavez

When Lorna Chavez moved from England to the United States in 1995, the land of abundance had a surfeit of skilled participants willing and able to don helmet and boot and join the nation's ranks of exercise riders. "I started in Delaware," said Chavez, a former jockey, of her time as an exercise rider for Hall of Fame trainer Jonathan Sheppard. But that was a quarter-century ago. "Now, there aren't enough riders around," she said. "Especially good ones." And that means busy racetracks of a morning are increasingly populated with...