Latissimus Dorsi (Lats)
Origin: Spinous process of inferior six thoracic vertebrae, lumbar vertebrae, crests of sacrum and ilium, and inferior four ribs. *
Insertion: Intertubercular sulcus of humerus.*
Muscle Action: Extends, Adducts, and medially rotates arm at shoulder joint; draws arm inferior and posterior.*
This weeks exercise to hit this muscle is Pull Ups
The Latissimus Dorsi is the only muscle in the body that attaches your arms to your spine. This muscle is responsible for creating the width of your back and is known for giving you what is known as the “V” shape. It is commonly know as the “swimmers muscle.” This is because several swim strokes replicate the muscle action of the Lat. Any type of downward pulling motion would work this muscle group (ex. pull ups). This muscle is also worked in rowing motions but not as effectively as in a pull down exercises (is not the prime mover). Therefore, lat pull downs and pull ups are the best way to work this muscle group. When you use a wider grip in any of these pull down motions you are recruiting more of your lats to complete the movement. The key to targeting the lat with any movement is to lead with your elbows and squeeze your shoulder blades together as much as you can. So if you are looking to increase your back thickness or perform more pull ups this is the muscle you want to target.
*Derrickson, Bryan. Tortora, Gerard J. Principles of Anatomy and Physiology. Hoboken: John Wiley & Sons, Inc, 2006.