If you’ve ever rowed a boat, done a pull-up, or deadlifted weight, you’ve probably felt the effects in your lats. Your Latissimus dorsi (lats) are the broadest of the main muscles in your back and are located in your mid/lower back.
The muscle is responsible for extension (rowing, swinging your arms as you walk), adduction (pull-ups, chin-ups, or lifting a heavy object from a shelf above your head) and rotates the arm toward the body’s midline (like when you fold your arms over your chest) and serves a minor role in assisting other muscles.
While your lats perform important functions, they also are largely responsible for holding the shape and contours of your midsection and chest. Developed lats make for a trimmer appearance.
For those into anatomy, here’s the official scoop on the lats: