A study from University of South Carolina Upstate (Spartanburg) shows that you can better target the lats with correct focus. The researchers had women perform the lat pulldown with just basic instructions or with verbal instructions on how to focus on the lats and minimize arm involvement. They measured the muscle activity of the lats with electromyography during each attempt.
They found that although the muscle activity of the biceps remained the same in both trials, the muscle activity of the lats increased by about 20% when the subjects received specific instructions. So, focus on pulling with your back instead of with your arms by squeezing your shoulder blades together and concentrating on the tension in the lat muscles.
