Ask someone in the gym to point to their trapezius muscles, and they’ll probably gesture toward the small mounds nestled between their neck and shoulders—but that’s really just the tip of the iceberg.

Four-time Mr. Olympia Jay Cutler built one of the thickest physiques in bodybuilding history—and when it comes to building bigger traps, he's not about to reinvent the wheel. In a new video, Cutler ...