You are given a total time of 6 hours to complete a 25 mile Limited Distance ride in the American Endurance Ride Conference rides. From that 6 hours you will need to subtract the time spent in Vet Checks and your ride time does not end until your horse reaches the specified pulse criteria at the end of the ride. So you're usually looking at 5 hours and some change.
Strength is certainly a requirement for a 5 mile race, but it is actually an endurance race.
1 mile
The Quarter Horse is fastest for sprints. They race a quarter-mile. Thoroughbreds are fastest for anything longer than that. Arabians are best for endurance. The fastest mile for a horse was around 1 minute, 35 seconds. This record was set by the TB racehorse Salvador.
5 minutes....less or more
The Quarter Horse is the fastest horse in the world, for a quarter of a mile. The Thoroughbred, most often used in horse racing, has more endurance for an entire mile, but still cannot beat the Quarter Horse in a quarter-of-a-mile race. Hence the name 'Quarter Horse'. This is exactly what you want in a horse when you are working cattle - short bursts of extraordinary speed.
1 1/8 mile (or 9 furlongs)
Endurance horseback riding is a sport within the equine world based upon very long distance racing. In endurance riding, the horse and rider travel a set course that is often a hundred miles long or more through wilderness. The horse and rider must train consistently and persistently to be in peak physical shape before starting the race, and there are vet checks throughout the race to ensure the horses are not injured or ill.
A race of stamina, who long you can go for without stopping
Over a short period of time, like a quarter of a mile, a quarter horse. They have been known to go up to 50 or even 55 miles an hour for a quarter of a mile. However, they cannot run that fast over a quarter of a mile. in a long distance race the thoroughbred would win.
One mile six furlongs, run at Doncaster racecourse in South Yorkshire
They vary in length, but as your question is posted in the KY Derby category I will say one and one quarter miles since the Derby is held at Churchill Downs and that is the length of that particular course.
For competition most people use Arabian horses. But in extreme long distance riding, nothing can beat an Akhal- Teke.