The Run for the Roses is a mile and a quarter long. It is a reasonable distance, and the traditional distance for the Kentucky Derby. It is a happy medium between the short distance of the Preakness Stakes (1 and 3/16) and Belmont Stakes (1.5 miles)
Last year the difference between the Derby and the Preakness was proven when Animal Kingdom ran out of time to win the second leg of the Triple Crown. What allowed him to win the Derby cost him the Preakness.
One problem with that, however, is that these horses have never run that distance. Typically, the Belmont (the last leg in the Triple Crown) is the race that is known for needing endurance. But really there could be problems for speed horses who just run from the starting gate.
This is why jockeys need to control their horses' willingness to just take off and run. If the horse runs out of energy in the final stretch, chances are they could lose it by quite a few lengths.
Here are some horses that will be racing in the 138th running of the world's most prestigious horse race.