If you are looking to work on your upper body and shoulder mobility this exercise for scapular retraction and T-spine rotation, combined with some hip mobility and hamstring mobility is about as efficient as it comes!
An important concept that is under-represented in the popular fitness scene is the movement of the shoulder blades. The movement of your shoulder blades together with your arm is hugely important for safe and effective exercise, so knowing a bit about the basics can do a lot for performance and