Why Long Slow Distance (LSD) instead of Slow Long Distance?

In running sports, LSD is short for Long Slow Distance (see wiki), and I am wondering why not saying Slow Long Distance instead of LSD.

I am not a native speaker, but I feel Slow Long Distance more natural and fluent. For instance, I have a slow long-distance running this morning.

Solution 1:

This has been the use of the term whether or not it came from being used to the letters L, S and D. Quoting from Training Myths: Long Slow Distance at http://www.allanbesselink.com/blog/smart/956-training-myths-long-slow-distance

"One of the primary bastions of endurance sports training concerns “logging in the miles”. Many call this LSD training – LSD standing for Long Slow Distance.

I always like to keep one phrase firmly in the forefront of my mind - “long slow distance makes for long slow [insert here: runners, cyclists, etc]”. The human body adapts to the training demands imposed on it. With that said, if you are training at a slow pace, then it stands to reason that you will get really good at running at a slow pace. I have yet to meet an athlete that was training to get slower."

To clarify; I would say that long and slow both modify distance less than they all modify running. For that reason either could be first or second.

In addition, perhaps primary after all this, in the case of Slow Long Distance one could only be describing their phone service: Long Distance. i.e whether my Long Distance is slow or fast. No searches I've tried come up with Slow Long Distance and I think for just this reason.