Do you have stubborn lats that refuse to grow? Maybe you're using too much bicep. Or maybe you're too busy doing chest. Whatever the reason, here's one way to fix it.
Next time you train back, instead of hooking up the standard bar on the lat pulldown, hook up a single D-handle. This can be done on a single or double cable machine.
Start with a pronated grip (palms facing forward). As you pull down, rotate your hand 180 degrees so you finish in a supinated grip position (palms facing toward your face).
This variation gives you a greater stretch at the top (good for muscle growth) with the pronated grip, and finishes off with a more forceful contraction of the lats with the supinated grip. Now watch your lats grow.