Stop doing lat pulldowns and start doing pull ups.
There are a lot of exercises that you see people doing in the gym that a lot of times are a waste of time or just pointless. Lat pulldowns are not necessarily pointless, but they are way over-used. People may get results from pulldowns but they are ignoring a better movement that the body is meant to do which will minimize the full potential of the movement.
As often as possible when performing a loaded lift you should be attempting to mimic a real world movement. This is what your body will respond the best to as you cannot easily trick 1000s of years of human evolution. Things like lifting a weight from the ground to over your head is a natural thing your body expects to do. There are A LOT of exercises you can split this movement into that make sense such as a deadlift, clean, military press, etc. That one complete range of motion breaks down into several exercises, or could be done in a single movement as a Clean and Press or Snatch. This theory is exactly why Squats are nearly unanimously the exercise annointed as the king by anyone in the strength training industry.
In the Lat Pulldown scenario that true real world movement that your body is accustomed to doing should be pulling your body to something. A Pull Up. This is my major gripe with pull downs, there is already a GREAT, closed chain movement for it in the Pull Up. This is the exercise people should be spending the majority of their Vertical Pulling time on, not the Lat Pulldown.
The general real world idea of a Lat Pulldown is beyond stupid. In what real world setting would you PURPOSELY pull down as much weight as possible down onto your head? This would likely end in a very similar manner as The Mountain's fight with Oberyn in Game of Thrones, a crushed head. Not ideal.
A real world application would be lowering a heavy weight from above your head but that action would feel more like a push as you SLOWLY lower something from above your head. Or the real world movement is pulling yourself up to something, again, the Pull Up.
The real truth when it comes to lat pulldowns is they are easier. Pull ups are a lot more work, people don't like real work. People like to use the Cables in the gym as much as possible because it allows them to look like they move a lot of weight, yet when in reality they probably cannot do 5 strict pull ups.
Do not be one of these people.
Use lat pulldowns as a finisher or supplement to the king of Vertical Pulling, the pull up. If you can't do a pull up, practice. Start with hanging from a bar for a set time until you can perform a full rep, keep adding time. Then move into bands or assisted pull ups, it will come with time.