LOUISVILLE, Ky. (AP) For its first 40 years, the Kentucky Derby wasn't the race it is now.
Things began changing after Regret captured the nation's attention in 1915 as the first filly to beat the boys in the race.
That achievement isn't lost on trainer Carla Gaines as she aims 100 years later to be the first woman to saddle the winner of America's signature horse race.
Gaines said Thursday, ''girls got this thing started, dude!''
The trainer of Bolo enters Saturday's race at Churchill Downs as the 16th woman to prepare a Derby starter and first since 2011. Shelley Riley finished second in 1992 with Casual Lies.
No female jockey has won the race either.
Bolo will start from the No. 9 post position in the 20-horse field. Gaines is among five first-time Derby trainers, but she hasn't always considered the historical significance for women.
''I'm just a trainer looking to win the Derby,'' Gaines said. ''If being a woman helps other women in the industry, then so be it.''
Gaines used the word ''traditional'' to describe the sport and the historically small number of women that have worked in its highest profile positions.
Mary Hirsch, daughter of famed horseman Max Hirsch, became the Derby's first female trainer in 1937. That came five years after she was initially turned down for a New York license.
The Kentucky Derby Museum's oral history collection includes the story of 1950s Kentucky trainer Mary Ann Cooper, who after passing a seven-page written test was asked to take an oral exam that she later learned was an attempt to deny her a license.
Cooper said in the collection that it was common then for women to enter horses in the name of their husbands to avoid problems.
Other historical information shows that as recently as the 1980s, some racetracks did not allow women on the backstretch after dark.
Though Gaines has benefited from the culture shift, she believes there is still room for improvement in a male-dominated industry.
''A horse is strong, powerful,'' she said. ''Maybe people think women aren't capable of handling them but women are great at dealing with horses. Superbly so, I might add.''
Gaines grew up in Mountain Brook, Alabama, and earned bachelors and master's degrees in sociology and psychology from the University of Alabama. Before working with horses she counseled troubled youths, developing nurturing skills and the ability to read non-verbal communication that she uses now.
''You'll have a horse that is very, very talented but has limited ambition. Just not interested,'' Gaines said. ''Other horses who are intimidated. Maybe a horse who is incredibly talented but you can't get him to focus. The same as people. You kind of work with them the same way.''
Gaines' first profession left her drained at times and she turned to her love of horses as a respite and eventually became hooked. She went to Louisiana for her first job breaking horses - training them to take riders.
Weeks of rain and ice storms that year made for a ''miserable existence to be riding outdoors'' and Gaines spent her afternoons flipping through horse magazines and dreaming of a new land: the West Coast.
''I would look at these pictures of sunny Southern California,'' Gaines said. ''It was pouring down rain and freezing cold and I decided, that's where I'm going to go.''
In the mid-1980s she took an industry job in the San Francisco area and got her trainer's license in 1989, staying there for seven more years before moving to the Southern California circuit. Her biggest win came in the 2009 Breeders' Cup Sprint with longshot Dancing in Silks.
Bolo, third in both the San Felipe and Santa Anita Derby after winning the Eddie Logan Stakes on grass, could be her best horse yet. He is 30-1 on the Derby's morning line.
Gaines is getting Derby advice from an unusual source: her bookkeeper, Patti Johnson, who trained 1985 Derby fourth-place finisher Fast Account. She praised the overlooked workers who keep things going and hopes to provide an example to follow.
Said Gaines, ''if you stumble around these barns, you're going to see a lot of women that are actually the backbone of the stable.''