It's out of your control
Marni Sumbal, MS, RD

As an athlete, you can control how you prepare for a race by focusing on one day at a time but you can't control what will happen on race day, until it is race day. And sometimes, even when you focus on what you can control (attitude, nutrition, pacing, clothing) things may not always go as planned so you have to adjust.
Obsessing over trying to control certain situations or getting upset, angry or anxious about things beyond your control is the best way to steal away energy that you can use on race day.
As an athlete, you have to be prepared for anything on race day and you can't let a race-day curveball like wind, rain, a modified course, temperature or hills keep you from doing what you trained to do on race day.... RACE!
With this being my 10th year as an endurance triathlete but also a coach to many amazing athletes of all levels, I feel it is important for athletes to distinguish between the following:
1. What worries you that is out of your control.
2. What worries you that you can do something about.
For examples, let's look at the following.
1. An athlete is worried about hills on a course because she/he trains only on flat roads and feels scared on hills (when riding) or not strong enough when running. While the athlete can not make hills magically appear where she/he lives, this athlete can make the investment to travel to a place nearby that does have hills to train once or twice a month to get more comfortable riding on hilly terrain. If there are hills on the run course, the athlete can run at an incline on the treadmill. Or, she/he can plan a trip to a bike-friendly location with hills to practice cycling or running on hills. If this is not possible, if anything, the athlete can arrive to the race venue a few days early before the race to get more comfortable on the race course. While the hills on the race course are out of his/her control, having the knowledge how to handle a hilly course (with the right gears, knowing how to change your gears, how to pedal efficiently, how to climb and descend safely and efficiently) as well as having some experience on hills will bring confidence to race day.
2. An athlete is worried about a bike course that has a lot of turns and u-turns. While the race course is out of your control (you can't change it), you can prepare for it. Practice, practice, practice. This is 100% within your control as you can practice your turns so you feel more comfortable on race day. Same goes for open water or running on a trail. Understand your race course and prepare yourself for what you will be dealing with on race day. If you complain about your race course and make excuses for not having a good race, but you don't practice or prepare for your course, your reasons for not doing well are not valid. If you prepare and practice but still struggle on race day, at least you tried which means you made the effort to prepare.
There's a big difference between making the effort and making excuses.
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Last year, Dr. G and I came up with a few situations on how to dodge a race-day curveball. We hope that you enjoy the article that we published on Ironman.com.
Here are two of our tips from the article:
Modified courseRespond, don't react. If possible, study the modified course ahead of time. If the course is modified at the last minute, remind yourself that everyone is in the same boat and probably feeling similar emotions and concerns. This should be validating, because everyone is mentally revising his or her race strategy. Remind yourself, you can't change the situation but you can choose how you respond to what happens to you. Don't react out of stress; respond by adjusting your attitude and rising to the new challenge. You didn't sign up for easy, right?