The rectangular body shape is characterized by a straight silhouette with not many curves, shoulders and hips of similar width, little to no waist definition and very long legs.
Many men are predisposed to a triangular shape, especially as they get older. It means being larger around the waist and hips in relation to the top part of the body.
This shape is the classic 'swimmer's physique': broad, developed chest and shoulders taper down to a narrow waist and hips.
If you're oval-shaped, your shoulders and chest are almost the same width as the bottom half of your body, and your waist is a little on the wider side.
The trapezoid shape means that the shoulders are broad, but not overly muscular or bulky. The waist is also the narrowest point of the torso.