Both lifters try to pull too far and too high on vertical pulling motions such as pull-ups and lat pulldowns. Rather than trying to touch the bar to your chest or reaching your chin over the bar (both of which can produce dysfunctional mechanics), the goal should be to achieve proper upper back and lat activation.
Think you have what it takes to make it in the world of elite sports? Do you have immense talent and ability? Great, but so do a few thousand other guys. Unfortunately, all of these things will only get you so far in this world where good often isn't good enough. At this level you have to be one of the best just to get your foot in the door.