Three of the "Big Six" Kentucky Derby Prep races are set to run this weekend. Much of our final assessment of the Derby contenders will be based on their last prep. In my mind the last prep is worth about 60% of my total consideration. Not sure how many have sat down to think about it in those terms but most likely you feel roughly the same about it's importance.
Fitness is a key factor and I think there are two definite angles to fitness. The first is whether or not the horse is physically healthy. There is no statistic to back this angle but it stands to reason that a horse needs to be physically healthy in order to run their best on Derby day. But another aspect of fitness is how well the horses body has been prepared to handle the distance. A horse could be bred to run two miles but if he's not been working out he won't get the distance. I have run 5 miles in the past so certainly I'm capable of doing it, but I have every confidence that if I stepped away from the keyboard right now and tried to run 5 miles I'd fade significantly. It's not because I can't run 5 miles it's because I'm not fit enough to do it right now. Same with horses, some people get sucked into the notion that if a horse is bred for the distance and is in good form they'll handle 10f. That is not always true.
Big Brown has already thrown down the gauntlet with a masterful performance in the Florida Derby. In terms of a final prep there was nothing to fault. But I do some doubts about his fitness, in this case I actually doubt both aspects of his fitness. It's well known that he's got foot issues so that may or may not be a factor but I also wonder if he is fit enough to go 10f. Traditionally horses have needed at least two preps around two turns to be fit enough. Those who failed to have a pair of preps around two turns have gone 17-0-0-0 in the Derby since 1996. Bellamy Road chief among them. Perhaps Big Brown could build his fitness level through long quick works like what Smooth Air had prior to the Florida Derby but for now that is a real question mark in my mind.
Here are some other quick facts you may want to keep in mind though when looking at the preps this weekend, especially when you consider the various horses who fail to win the preps.
Horses whose finish position was worse than position at the 1/8th pole in either final preps have not fared very well in the Derby. They went 60-1-4-3 with Silver Charm in 1997 the last and only winner to have defied this angle. Basically you don't want your horse getting passed in the last 1/8th. This is often an indication of a horses fitness because if they're unable to sustain a run or finish strongly going 9f they'll have a very tough time doing so at 10f. Incidentally the aberration to this statistic, Silver Charm, was passed in the stretch of the Santa Anita Derby by Free House but he essentially lost a head bob during a stretch duel. Free House did not blast past him and Silver Charm was not giving up.
Also stay away from horses who did not either win or finish within 3 lengths of the winner in their last prep. There are two aspects at work here, firstly you don't want a horse who has just run a dull race but also you don't want one that was outclassed. Many Derby winners did lose their final prep but none of them were beaten a distance. In fact horses who failed to either win or finish within 3 lengths of the winner in their final prep went 83-0-4-1 in the Derby
If you're looking for a more contrarian angle you may want to play against horses who ran off and won by a huge margin in their last race. Horses that won their last prep by 5 lengths or more
went a surprising 16-1-0-2. War Emblem is the exception. It's not a stat I'd put the mortgage on and I do believe there are better ways to predict bounces off of big efforts but it is interesting that the most impressive runaway winners in prep races almost always failed to duplicate that effort in the Derby.