What do you notice about the top two photos?
I'm essentially laying down.
Swimming is like napping on a water bed, with arms and legs moving.
Biking is like being propped up to read a book or watch TV, with just the legs moving.
There are parts that can be a little lazy if they want to be, while swimming and biking.
Running is nothing like napping, nothing like reading a book or watching TV. Nothing can be lazy. Everything has to be committed to forward motion.
It's totally vertical.
That's why my expression usually looks like this by the run.
I'm hurrying to the finish, to hurry to be lazy.