What causes “rounded shoulders”? What makes an otherwise healthy person with good shoulders (probably even someone that exercises) get shoulders that roll forward in front of their body? It may be slightly different for each person, but I think most people can be put into the following categories:
People that are on computers for most of the day
If you’re sitting in front of the computer all day, your posture is that of someone with round shoulders. You are forced to do activities in front of you all day. It used to be that this type of problem was reserved for hairstylists and mechanics. People whose occupation forced them to have their arms up in front of them all day. Now it’s all about being on the computer.
People that are shy (or were shy) at an early age and learned how to fold their arms in front of them
This seems to be more common with girls, but I can see this posture develop early. This is reserved for those that develop early or that are taller than their peers. They learn to stand in a way that they think will help them fade into the background rather than embrace themselves for who they are.
People that do an uneven amount of exercise
That is, people that may go to the gym and break up their routines evenly for different body parts. “Today is chest, tomorrow is back, then arms…” Most people do it this way. I think this way of looking at your routine doesn’t take into account what your normal daily activities are. Chances are you really should be working out your back twice as often as your chest to balance things out.