I asked my Mama about this once (her family raised show horses and she knew several race jockeys). Her answer was interesting, as she said that decades ago a Russian thoroughbred was banned from professional races after it was discovered his owners had given him a type of diuretic to enhance his performance. According to the investigators that looked into the case, the diuretic was so strong the horse ran faster in order to reach the finish line and release his urine (the med also allegedly damaged the horse's heart). Anyway, Mama said this is where the term "Faster than a Russian race horse" comes from; a saying indicating someone is hurrying like they have to pee QUICKLY. And as Mama knows her equine history pretty darned well, I tend to believe the story.