Maybe 20 or 30 years ago I read a short story recounting a futuristic raid (I suspect on another planet) on an enemy settlement by (I think) a handful of soldiers. I think that they more or less run through a forest or jungle, too quickly and expertly to be intercepted. I don't recall exactly what their mission is (possibly a specific assassination... not at all sure...), but they execute it with single-minded efficiency and return to base. I think that their losses are minimal, perhaps zero.
As far as I can remember, one of the story's main points is for readers to realise that these guys are enhanced in some way: biologically, chemically and/or cybernetically. I have a feeling that this kind of mission is nevertheless so physically taxing (on whatever proportion of their system is still human) that these soldiers cannot be deployed often.
I think that the story ends with them returning to what amounts to a kind of storage, to recuperate or recharge for next time. I think we are allowed to realise that these soldiers' conditioning is such that they have no concept of any other kind of human existence: their entire world is these occasional missions.
I have been searching for this story for a few years now. The author must have been well-known enough for the story to make it into a fairly high-profile anthology, but I now can't find it anywhere.