This comment from another post:

https://piefed.zip/post/1760956#comment_6754022

There’s this story that Mark Hammil tells about being on the set of Star Wars and he mentions to Harrison Ford that their hair should be wet, since it was just wet in the previous scene.

And Ford says something like, “This ain’t that kind of movie, kid. If the audience is talking about our hair, something has already gone wrong.”

The same goes for Reacher, even the books. They're great, easy and fun to read, but if you start thinking about it like that something has already gone wrong.

Even so, I have to say that the books concentrate more on him just being really tall without being thin. And trained both mentally and physically, but never just muscled.