I decided to do lat pulldown yesterday, asked the trainer to watch my form and advise me one what I'm doing right/wrong.

He said that my shoulders were pushed up (Like a shrug) causing me to use more of my bicep and shoulders. Raising my hands up, he asked me to move my arm up and down with the lats. My ROM was about 5 cm. He had a much larger ROM. He suggested I simply pull down with that ROM until I can stretch it beyond that (Does this make any sense?)

I tried pulling down and into my lats rather than pulling like a row. I tried keeping my shoulders/traps, low, not raised except when extended. Does this sound right? I'm gonna have to get a camera in there and do a video, but I don't know that would help. Is it possible that overdeveloped muscles in shoulders etc can affect how a person moves with other muscles? Perhaps I've been ignoring my lats for too long.