Posted on Quora, a really interesting forum on all subjects.
"How is strategy used in horse racing?"
As soon as the entries for a race are set and available, the trainers, owners, jockey agents, and the more detail minded jockeys are handicapping the race to determine strategy by examining the past races of each horse in the race. Post position is huge because a horse that usually gets out of the gate early and likes to be close to the front of the race early can get cut off and boxed in. A heavy favorite will be targeted by all the riders who will try to keep him behind horses, down inside or far outside. A heavy favorite that has an outside post position and doesn't need to be on the lead early is very dangerous and more likely to win. The strategy for such a horse is to take his time, ease up slowly and try to get position to make a clear run to the finish. By race day, everyone involved with the horses has mapped out how they expect the race to go and where each horse will be in the race at all times. In the paddock before the race, the trainer, owner and jockey will have a short pow-wow to discuss how they think the race will play out and what the jockey's strategy should be. Despite all this, the best laid plans often go awry and the jockey then needs to fly by the seat of his pants to try to win or at least finish strong.
Long term strategy is also important. Good trainers plan a horse's races carefully, picking out a race to aim for and training up to the race to hopefully have the horse in peak condition on the day of the race. Entering a horse in the right type of race is also crucial because each horse is competitive at a certain level. Most horses are only competitive at a certain distance (short, middle or long) and on a certain surface (turf, dirt or artificial). It's difficult to find the perfect race to fit a horse at exactly the right time he is ready for a race but it's the trainer's job to do that.
Trainers often lobby the racing office to try to make sure an appropriate race will be available for a horse that needs a certain type of race. Trainers have a book from the racing office that lists each race that will be held on each day of the racing meet, but the racing office also adds races to those available in the book in order to maximize the possibility of having a lot of horses in each race. The races that have the most entries for a day will be the ones that actually are run. If less than 6 horses enter a race, the office usually does not use that race and the trainers who entered will have to pick another race to enter. Thus trainers have to be in constant planning and strategy mode in order to find the right race for a horse at the right time.