Sentence:  ... Lou was a respectful reader of the boy books that were emerging then, those magazines of black-and-white photos of teenagers with shaved chests, sucked-in if <WSD>unexercised</WSD> stomachs, and cloth posing-straps who stood on a dais silhouetted against a sunburst of seamless paper. 
Meaning of the word marked with <WSD> tags:  Not having been subjected to physical exercise.