If you ever walk into the gym and see guys with terrible back development, you know they’re the ones who don’t do a full range of motion. They can be seen either not bringing the bar all the way down, or not extending all the way to the top.
The lat pulldown is one of the kings of back exercises. The back has lots of different muscle groups that need to be hit from many different angles. In general, a wide-grip pullup or pulldown and a pronated-grip pulldown both appear to produce greater EMG activity of the latissimus dorsi than a narrow grip or a supinated grip.
There isn’t much research on how the traps are activated during the lat pulldown. Researchers examined muscle activity during different positions of the lat pulldown and found that the latissimus dorsi was activated the most in the fully contracted position of a pullup or pulldown, while the lower trapezius was activated the most in the fully extended position of a pulldown or pullup.
So make sure you pull the bar all the way down and extend the arms all the way to the top to get maximum activation of the target muscles. - FLEX