Look up the word "obsess" in the dictionary, and you'll find the following:
"Preoccupy or fill the mind of someone continually, intrusively, and to a troubling extent."
All elite distance runners fall somewhere on the spectrum of obsessed. You could argue the degree of obsession is determined by how "troubling" the extent to which they obsess is.
That level of commitment is expected.
I have yet to come across any expert in their field who isn't at least a little obsessed about perfecting their craft. And that makes sense.
To become skilled at anything, it has to be repeatedly practiced. To create the consistency required for repetitive practice, the activity must take priority over the lion's share of alternatives. In fact, one could argue that it has to take top priority. For that prioritization to occur, the activity will "preoccupy or fill the mind of someone continually [and] intrusively." And thus, obsession ensues.
Just as obsession can pave the way for success, it can also become its greatest inhibitor. Anyone who has become too deeply entrenched in their obsession has found its dark side, whether they want to admit it or not. At some point, doing the activity becomes more about calming the mind than actually improving ability (again, whether the person wants to admit it or not). Quantity of practice trumps the quality.
I see this a lot in running at the collegiate level. ALTIS Head Coach Dan Pfaff has a great way of explaining it:
"When you are young and try harder, you get better. But there is a tipping point somewhere in your evolution where trying harder is the enemy. However, by that time you are addicted to trying harder, since in the first three years of your development trying hard was the magic answer."
In my opinion, one of our greatest responsibilities as college coaches is teaching self-awareness. It's opening an athlete's eyes to the double-edged sword of obsession. It's teaching gratitude for the discipline it has brought, coupled with the awareness for the traps it can set. It's recognizing the dance of stress and rest that creates growth. It's defining the purpose (i.e. the telos) of each run. It's emphasizing quality, and only in the quantity the athlete can handle.
Because, as the platitude goes, it's not always about more. It's always about better.
And more isn't better.
Better is better.