Your body can be in peak condition for a race, but if your head isn't in the game it can have a detrimental effect on how you do. A running mantra can help get your head back in the game and push through that wall during a race.
According to this article the ideal running mantra is "One that's short, positive, instructive, and full of action words." They also recommend having several different mantras ready.
I used quite a few in the last few years since I started running halfs and one full marathon.
At the start of a race it is all about "Run your own race" to prevent me from going out too fast and trying to keep up with all the people who do start out too fast. I also use "I will be seeing you later" at the beginning. and some of those people I do see later, because they started out too fast.
Other ones I have employed with success are "Enjoy being fast" and "This is what you are here for, this is what you trained for. You are ready for this. You are trained for this" Okay the second one isn't very short, but it is very motivational for me. Repeating it over and over can really get me in the zone.
It is important to dig out these mantras when you get a stitch in your side, feel like puking etc so that instead of focusing on the pain and letting it drag you down, you distract yourself and push on. Mantras help divert the mind from its dark thought and transcend the pain.
Tips for making a good mantra.
Stay positive! Remember you want to divert your mind from the pain, not focus on it. "This is my day" Use energetic words. "Go for it" "Run strong" Keep it short. You don't want to be struggling to remember your mantra, it should flow easily. Make it instructive. Tell yourself what to do. Remind yourself how you should be feeling. "Be relaxed" "Dream Big"
or you can use this chart to help make a chant to pull you through on your run.
The biggest key to a running mantra is finding one that works for you. If it doesn't resonate with you it won't be as effective. I like to try new ones out when I am doing a hard workout. Sometimes even the distraction of thinking up new ones is enough to help pull me through the workout. Tell me some of your favorite mantras. One of my favorite mantras of all time for races is:
Make this moment count.
Others I use:
This is what I do.
I can do another mile, what is another mile, nothing to me.