Horses that start from a post position near the inside rail have a shorter distance to travel than horses which start from the outside post positions. That is a given. However, they are also susceptible to being cut off by quicker horses as those horses head to the rail, and of being boxed-in at a later stage in the race.
It seems like a wash to me, but there are those who will point to statistics and tell you that currently at Arlington Park horses that have started from post one in sprint races have had a two percentage point advantage over horses that have started from post three. What these amateur statisticians often fail to ask themselves when they find a minor anomaly such as this is: What caused the anomaly? Does the perceived two percentage point edge in sprints exist because the horses that have thus far started from post one have traveled a shorter distance? Or, could it be that in the 302 sprints run thus far, better horses have started from post one more often than from post three?
I tend to believe it is the latter reason and to back up my belief I will present statistics from the recently completed Saratoga meet where there were 167 sprint races conducted. Unlike Arlington Park, horses that started from post one were at an eight percentage point disadvantage compared to horses that started from post four. Does that mean you should have spent more time focusing on horses that started from post four than you did on those horses that started from post one? Of course not.
Handicapping is all about finding the right horse, and if a horse is fit and ready to run the post position it will break from will have little, if any, influence on the outcome of the race. The post position a horse breaks from will not make the horse run any faster than it is capable of running.