Stretching lat is not as important as chest stretch. Yet it is always good after the muscles are trained. Especially if you have a tight lat, try to add those stretches in your routine. I can also help you stretch by partner stretch at the end of personal training sessions.
ILS
ILS stands for invisible lat syndrome. Ego may be one cause for this look. Some people feel that if they walk with their arms out from their body and the palms facing back, it makes them look like they have worked out. The shoulders are rounded, the arms are not the side, instead they are out from the body and the palms face backwards.
Other factor for being ILS
Other than ego, having tight latissimus dorsi, subscapularis and pectoralis major may cause this posture. And as usual, a desk job can contribute to this posture. It can cause neck back pain and headaches.
Lat Stretch 1
An arm towards the ceiling, then lean towards one side. If you are Japanese, you know this from radio-taiso, but don’t bounce like you used to. Bouncing stretch (ballistic movement) is not good for you at all. Hold the position for at least 30 seconds and do the other side. It may be easy with TRX.
Example of radio taisho (go to 1 min to see the stretch)
Lat Stretch 2
If you have low back pain, this one may be suitable for you compared to one above. Kneeling down, the head and hands on the floor, then your hands point slightly left in the direction to start. You want to put some weight on the right shoulder joint. You should feel the lat is stretching. Hold it for 30 seconds and do the other side as well.
When should you stretch
You should never stretch cold muscles. Also, you don’t want to stretch right before the strength training. Try to do it when you are warmed up, which is usually after working out. But don’t overstretch!
Exercises for chest stretch and Thoracic mobility here