One of the toughest realities about handicapping and betting on modern horse racing is that there is a whole lot you don't know regarding the health of the horse in between races.
In the old days, they'd have published workouts left and right -- as horses raced and especially worked a lot more frequently.
In the old days, they'd have gossip writers all over who would make it their business to go out and find any rumor about what might be bothering a horse, and they'd report it in print.
Everyone but the trainer (and sometimes the owner) is in the dark. You really learn that lesson when you claim one or two that has real physical issues.
Here is what the published reporting would look like in the old days: -- they would rely heavily on unnamed sources.
