A bad race.
Letting go of the past needs to be learned because we are biologically wired to focus on thing that go wrong and gloss over stuff that goes right. This wiring helps our brain adjust future thinking and behavior. Verbalize your anger or frustration in order to connect the emotional outlet (verbal) with the thing that caused it (describe the event). Then determine if the cause was within your control or not within your control. Now go through "within-my-control" items and devise a strategy to reduce the likelihood of it happening again. Lastly, identify a positive from the race. It takes mental toughness to refuse to quit and still finish (even if slow).
The judgments we make about ourselves and our abilities can be crippling. If you constantly compare yourself to other athletes and conclude that losing makes you feel worthless as a person, it should be clear why this is damaging. Give yourself lots of opportunities to experience success. Use strategies to manage your inner critic, or the voice that is constantly reprimanding you for screwing up and not being good enough.
For the vast majority of us, our brains are biased to take personal credit for success and externalize reasons for failure. Ask a triathlete to explain the reasons for a poor performance: I forgot my nutrition, I dropped my chain, I got beaten up in the swim, a marshal sent me off course OR the opposite, blaming external factors like I'm not fit enough, good enough or talented enough.
1. Did I fully commit to it? Was I brave enough to give it everything I had? (Effort goal)
2. Was I grateful and positive? Did I take time to appreciate where I was and what I was doing? (Attitude goal).
"Morison rule" - never quit on an uphill. Put off decisions about quitting until you get to the easy parts of the course. You'll be amazed by how effective this simple strategy is for staying in the game.
Train yourself to recalibrate how you define success and failure. This doesn't mean that finish place or podiums are unimportant, just that during the race (or training session) you only focus on things that are always in your control - effort and attitude.
1) Segmenting: Use distance or time markers to carve up the session so your head only has to cope with small periods of pain at a time.
2) Counting: Like Rain Man. Counting works because your brain finds it easy, there's an explicit sense of progress (numbers go up or down) and the repetition can help you get into a hypnotic state.