A muscle shirt (or sleeveless tee) resembles a standard t-shirt with the sleeves removed, featuring broader shoulders, standard necklines, and a tighter, contoured fit designed to showcase your physique.

A tank top is the upper portion of a tank, typically called the turret, containing the cannon and firing system which can typically rotate to better acquire targets.

If question: Muscle shirts (sleeveless tees) are usually less revealing than tank tops, which are narrower at the shoulders and can have huge armholes that expose more of the torso

If riddle: idk, what?