Unless he isn't an atheist? Plenty of theists can hold to evolutionary views or intelligent design.

Further, the language choice could be colloquial in which case he wasn't trying to make a theological statement; rather, op used common phrases to convey the relevant thought. not sure we need to push a worldview here...

I didn't assume they were an atheist. The language choice was used to confer normative value to long-distance running. This isn't pushing a worldview, it's pointing out that the basis for this argument for long-distance running is something which is not coherent with many readers' beliefs.

Would "adapted" be a better word in your opinion?

evolved

It's standard to refer to the outcomes of evolution as having been designed by evolution, with no one assuming that requires a "designer". Perhaps it's just easier to say than "emergent design", but it also communicates more about how evolution actually works via this metaphor. The system as a whole designs complex solutions to problems, without self awareness, that's the amazing discovery.

For what it's worth the entire field is fine with this language and no one takes it assume any superstitious beliefs.

And a body of water does not "want" to flow to a local minima, but personification is a damn useful rhetorical device anyway.

I'm of the opinion that rhetoric which imbues evolution with purpose damages understanding far beyond your water example. It is common to see people cite evolution in moral claims, for example: "we evolved to eat meat". I'm not interested here in the question of whether or not eating meat is moral, I'm pointing out this is a bad form of argument which is encouraged by lazy language use when dealing with evolution.

I didn't downvote but I wouldn't be so sure either. Design as a figure of speach can mean a lot and, baring the discussion about determination and free will, creating and making can feel very passive. Intent is often open ended.

I downvoted because it's tiring and pedantic to raise the objection every time someone says "designed for" in the context of biology. Yeah, we get it: evolution has no designer. It doesn't matter, because the semantic space is well understood. The figure of speech "designed for X" just means it's narrowly optimal at X -- it's good at X at the expense of being bad at not X.

Hence explanations like, "A cat's digestive system is designed for meat: it has enzymes Q and Z which are really good at breaking down flesh but also react poorly to plant matter." We get the point. We don't need a reminder that, "well, the scientific consensus is that the cat digestive system arose without an intelligent designer".

That's a very good definition of "designed" that I hadn't seen before.

Thanks. I didn't mean to suggest it was a documented definition, so much as "the characteristic that makes it 'feel' like a human-designed thing" and makes us want to refer to it that way, even when knowing it wasn't.

things can be beautifully engineered and designed by a process called natural selection.

when the word design or engineered is employed it does not always mean designed by a God.