i honestly repeat this in my head when I feel like giving up. I had a friend who was an avid runner and he suffered a spinal cord injury due to being in a car accident and could no longer run. I always think about him and how he would give anything to run so I should keep going.
This is the moment when you "swear" your body is going to drop, but it's at that very moment, when you dig down deep, and YOU tell your mind and body, "Suck it up....buttercup!" ( the last quote is taken from Lisa my Les Mills trainer)