It's been almost 55 years since Dr. Fager set a world record for the mile distance when winning the 1968 Washington Park Handicap at Arlington Park in 1:32 1/5, a record that has yet to be broken. In 1973, Secretariat won the GI Kentucky Derby, covering the 1 1/4 miles in 1:59 2/5, a record that still stands 49 years later. There are other examples, all leading to the same conclusion--the Thoroughbred racehorse is not getting any faster. Some believe that horses have gotten as fast as they can get,...