In the case of things that have already happened, you must tell yourself nothing can be done about the past. Take the past and learn from it in order not to repeat the same mistakes in the future. Continually learning from past mistakes and making changes that improve your chances of future success is how you gain mental strength. Like physical training, mental training is a continuous improvement process and not a one-step-to-success program.
As for worrying about the future, the big question is: what actions can you take right here, right now that will have the biggest chance of positively affecting your future?
For example, some athletes worry about the training that other people have completed. Remember, on race day there is only one athlete's training that you can influence—your own. You can do little to nothing about the consequences of someone else's training. When you begin to worry about the past, recognize this self-defeating problem and bring yourself into the present.
Ask yourself "What do I have control over, here and now? What can I do to help me get closer to my goal?
During the swim, set goals of reaching individual buoys, perhaps doing it while overtaking at least one person or remaining in the draft of the fast swimmer ahead of you. When you reach that buoy, set a similar goal for the next one. On the bike, set goals to reach objects in the distance without dropping below a certain speed.
By breaking the race down into smaller segments, you can experience success every few minutes. These small successes are forms of self-reinforcement and can add up to a successful race day.
Keep the End in Mind
When you are evaluating the options of what to do in the here and now, keep the end goal stored in the back of your mind. This will help you make the best decision in the moment of battle.
For example, if you happen to drop your hydration bottle during the race, you might be tempted to keep going and not stop to pick it up. You reason that not stopping will keep your average speed high during the bike portion.
If you get behind in nutrition or hydration later in the race, however, you may be forced to slow down or stop for a while in order to recover. Taking a short-term action that negatively affects your overall goal is not a wise choice. Before taking action here and now, consider any potential negative consequences to your end goal.
These three tips are merely a start on mental-toughness training. The best athletes have multiple mental skills in their toolboxes. They are constantly improving on those tools while adding new ones. They view themselves as top problem solvers and love the process of overcoming potential performance obstacles by just thinking them through.
If you welcome the challenge of overcoming obstacles, you have an edge on athletes who fear problems.
Everyone is doing the physical training to complete an Ironman, not everyone does the mental training. It's a long race to be alone with yourself. Train your brain to tackle problems head on and focus on moving forward to your goal.