The lat pull down gets its name from the primary muscle it targets: the latissimus dorsi. Multiple other muscles assist and stabilize during this cable-based exercise, including the pectoralis minor. The pectoralis major, the primary chest muscle is not activated during the lat pulldown.
About the Pecs
The chest muscles are made up of the pectoralis major and pectoralis minor. The pectoralis major is the large, fanlike muscle that covers the front of the chest. Beneath it lies the pectoralis minor, a thin, triangle-shaped muscle. The pectoralis major is responsible for major movements of the shoulder, including internal rotation, raising the arms out to the sides and lifting the arms overhead. The pectoralis minor has slightly different responsibilities; it works to draw the shoulder blades into depression, to move the arm away from the body and to rotate the shoulder downward. Working the pectoralis major gives the chest its muscular appearance. A strong pectoralis minor is important to body function but does not contribute to size and tone.
Lat Pull Downs
Lat pull downs activate the pectoralis minor as a synergist, a muscle that assists the primary mover -- the latissimus dorsi – the action. Other synergists in the movement include the muscles of the forearm, upper arm, shoulders and upper back. The pectoralis major is passive during lat pull downs.
Working Out the Chest
A 2012 study sponsored by the American Council on Exercise named the barbell chest press as the best exercise to activate the pectorals. A close second was the pec dec machine and then bent-forward cable crossovers. To get the most gains for your chest in the least amount of time, use these moves interchangeably, says lead researcher John P. Porcari, Ph.D.
Considerations
Despite not targeting the major muscle of the chest, lat pull downs are an important part of any upper-body routine. Even if you are after a big chest, you need to work the back to provide balance to the body. Strong pectorals provide power in pushing maneuvers, while strong lats help you pull. A strong back also contributes to good posture so when you do show off your chest, you appear tall rather than hunched.
