"[T]here are known knowns; there are things we know we know.
We also know there are known unknowns; that is to say we know there are some things we do not know.
But there are also unknown unknowns – the ones we don't know we don't know."
Such as in war, so as in racing. We spend months, sometimes years training and preparing for certain races and in the end there will always be aspects that are completely out of our control.
Some of these things are obvious and known to all, for instance, the course. Being that it is usually proper form to lay out the course before race day, we can easily look at the route and study it. The more studious amongst us will also try to train on the actual course in order to become familiar with it. For races like a relay the organizers send out a course packet with each leg's map and elevation chart so that we can review what we will be running.
The known unknowns would include uncontrollable aspects of race day such as the weather. With the relay this weekend it looks like we have gotten really lucky. Tomorrow it is going to be over 90 degrees, some reports top it out at over 100, and humid but that weather pattern will clear out by Friday leaving us with temps from the 50's to the low 70's. The difference of 48 hours is looking to be the difference between excellent running weather and an absolute weekend of hell and misery (think: being stuck in an elevator with Carrot Top for two days).
Another important known unknown for many runners when racing is who else will be racing that day. While this may only be a factor for those runners trying for a win (overall or AG) it is definitely a huge part of racing. After all, you way run the race of your life but if you are up against an Olympic qualifier then chances are you're not going to win.
Now as for unknown unknowns, well, these are the things that we either don't even realize that they can effect us or we just fail to even think about them during race planning. For instance, the tornadoes that hit western Mass last week have forced some of the legs of the relay to be changed. Who could have seen that event coming?
There are countless things that could be considered unknown unknowns and I tend to categorize anything that I ignore in that category. Unfortunately one of those things hit me last night at 1AM. I woke up and had trouble getting back to sleep because I was having trouble breathing right. My throat was sore, I was choking, and yup, my glands were swollen. Damn, I was getting a cold four days before the relay. I categorize this as an unknown unknowns just because there is nothing that can be done about it. I can't plan to not be sick and even if I do have a cold there is nothing more that I can do about it then what I am doing on a normal taper. It's a fact of life and it sucks balls.
Ultimately, one has to just ignore the unknown unknowns and learn not to stress out about them. There is nothing that you can do to try and mitigate problems when you don't even know what they may be. Focus on what you know and can control, or at least plan for those things that you can't control but may be able to mitigate. Much of the anxiety for some in the lead up to a big race is the fear of the unknown. This is counter-productive. It is good to have a plan. It is good to be nervous and excited and to triple check your gear and food and drink and etc. Channel your energy into that and stop worrying about what you can't control. At the end of the day we're just racing ourselves, everything else is just background noise.