Poor posture can be the result of many things including muscle weakness, muscle tightness and/or laxity, and bad postural habits that I will call postural laziness. The most common type of poor posture in women is a combination of a rounded upper back, forward head, and slumped shoulders. This posture can start to develop early in life, but certainly worsens with age as the undesirable changes in muscle mass and bone density progress.
When your back rounds and your shoulders slump, the muscles on the front of your body are placed in a shortened position that can lead to tightness, while the muscles on the back of your body are placed in a lengthened or stretched position. When you keep your body in this position for long periods of time, adaptive lengthening and/or shortening of these muscles occur, which means they permanently change their length. I should not have used the word “permanently” because you can change it, but for sake of making a point please cut me some slack.
If you wish to improve this type of postural deficit, the first line of attack is to stretch out the chest and anterior shoulder muscles, while strengthening the muscles of the back. There are many ways to stretch the chest muscles but the easiest way to explain in text is to put your hands behind your head and pull your elbows back, squeezing your shoulder blades together. To strengthen the back muscles, performing rowing-type exercises where you squeeze your shoulder blades together are great. This can be done with rubber bands/tubes, free weights, or weight machines.
I mentioned that a cause of poor posture is also postural laziness. This is basically having the habit of letting your shoulders slump. To successfully change your posture you MUST make a conscious effort to maintain good posture and this can be very difficult as bad habits are very hard to break. My advice is to start a postural-improvement training program while at the same time working on breaking the habit. You must have a foundation of good muscle strength to maintain proper posture or your attempts will only last a couple of minutes before your shoulder blades are burning from the weakness and your shoulders slump from fatigue.
It is surprising what a hot issue this is for women as I have had many mothers bring their daughters in strictly for postural improvement, as well as adult women that are concerned about their future. Poor posture predisposes you to a number of orthopeadic conditions including rotator cuff injuries, stress fractures, and numerous back issues. It is never too early or too late to make an improvement.
If you choose to make a change to your posture I would suggest seeking someone with formal education in postural analysis and body mechanics. While it is easy to see rounded shoulders, only a professional can identify other subtle postural deficits that can make a significant impact on the big picture. When you straighten up someone’s rounded shoulders, unfamiliar stress is placed on other structures and you do not want to develop problems elsewhere.
So your mother was right again…stand up straight and throw those shoulders back!