Chances are that if you are reading this then you have an anterior dominant posture. It's not your fault. Well, that's not really true, but it is true that you can do something about it. First though you might want to understand why you should care.
Put simply, the anterior dominant posture is the position where your shoulders are rounded forward. The cause of this position can be an imbalance in muscle strength, tightness, protection, ischemia, weakness, laziness or social acceptance. The cause is important for understanding how to best address the posture and is best determined individually, and the impacts to the body from the position are important for finding the reason why you should place the value necessary to making a difference to the posture.
To the neck:
When your shoulders are rounded forward more of your body weight of the upper body is pulling your head forward. If you allow your head to go with that pull then your muscles have to work a bit harder but there is not the increased tension in the neck until you raise your eyes, but looking down at the ground all the time makes it a challenge to interact with life. Keeping the eyes level with the horizon is one of the primary physical goals and to attain this position with your shoulders forward requires the neck and upper back to make some potentially drastic adaptations all of which can be summed into increased stress, tension and progressive degenerative changes.
To the lower back:
To counter the forward weight of your upper body in the anterior dominant posture your body will find a way to lessen the amount that the muscles have to work by placing greater amount of your weight onto the discs in your spine. In appearance the lower back in this position is flat rather than having a natural curve and the butt is tucked under. Over time this adaptation progresses from a straight/flat back to one that looks more like the letter C from the side. Again, the progressive physical changes in the spine are placing greater stress to the discs between the vertebrae which can lead to bulging or herniating them.
To the shoulders:
Regardless of the impacts to the rest of the body the rounded shoulder position can have negative consequences to the shoulder joint and its many muscles and soft tissues. To simplify, imagine that you are threading a needle but as you are pulling the thread through the hole in the needle gets smaller and smaller. As the space for the thread gets smaller it will become harder to pull the thread and as you continue to pull the thread will begin to fray. The space is just not large enough. This is a very simplified attempt to explain what happens to the rotator cuff muscles in the anterior dominant position. There are other tissues around the shoulder joint that also can be damaged in this position, but the rotator cuff surgical repair is so common it makes a good example.
As hopefully is clear from these simplified examples, the rounded shoulders posture can be the cause of many degenerative conditions of the body - conditions that sometimes are misidentified as having a cause other than biomechanics. Remember that orthopedic injuries can be categorized into one of four categories: abuse, disuse, misuse or trauma; and of these trauma is the only one that is not biomechanics in cause.
Understanding the role that your posture and biomechanics has in your health provides you with the knowledge to be able to choose different. This is not to imply that it is easy, just that it is within your power.
As always, let me know how I can help.