Every concept is prone to oversimplification and misunderstanding, but “functional training,” as overused as the term may be, has led to a wonderful re-exploration of human movement.
This progression will help open up your hunched, rounded, slouching upper spine.
Lifting is fine, but in the real world, we pick things up to carry them.
Our response to a cranky psoas is often to try to stretch or strengthen it, but we may need to just relax it, instead.
Five minutes of twisting into various shapes isn't going to overcome the other 99% of your day that you spend getting tight.
Once I stopped trying to force myself into a position from a book, I found my perfect squat.