Latissimus dorsi starts from the upper arm and goes all the way to the lumbar part of the spine. In many cases exercising doesn’t affect the lower part of the lat, partly because of the bad performance and partly because of the poor choice of exercise.
Pull ups are the best for the lat. It’s enough to start with 8 sets of 8 repetions, every 3-4 days. If you cannot do more that one pull up, then do 10 sets of 1 and then move on to the lat machine.
The next exercise is dumbbell row, then pull ups and finally deadlift.
Triset lat workout
Exercise 1 – Wide grip pull ups until you call it quits i.e. until you cannot do it right, without bending, changing grip, shortening the way etc. It is to be done first since it’s the most demanding. When you’re in low position, lower your shoulders as much as you can, and lift your chest up. When you’re up, don’t hold your elbows behind your body, but below the pull up bar.
Exercise 2 – Decline rope pullover. It excludes the shoulder and chest area. Switch the angle by changing the cable extension. Combine constant tension and small/middle weights. Don’t bend your elbows during the action and don’t push your chest toward the ceiling. There is no need to bring your hands back toward your knees and to make them stiff, go somewhat over 90 degree angle.
Exercise 3 – Modified low pulley row. With a mild bent work for the middle and back part of the lat. Work with a grip and during the whole set don’t change the chest angle (the hamstring stretch). There is no need to use heavy weights. Back and shoulders should be as low as possible in order to spare your trapesius muscle.