Do what the stats tell you.

So the famous "they" say that one is more likely (like 80%) to achieve a goal that he or she writes down. -and even more likely to achieve it if he or she visualizes it and speaks it out loud. 

Last night, I wrote down "4 MILES. RUN. 1 HR & 1/2."

I got up this morning and said to myself, "Self, I'm going 4 miles today without stopping no matter how fast or slow I move, I won't stop. I think I can do it in 90 minutes."

In the car I said it out loud to myself. 

On the treadmill I just saying that the miles number will flip to 4. It WILL flip to 4 before I stop. 

Boom.