Myth #1: Thinking about your posture is enough.
Truth: Postural alignment is unconscious and based on our muscle memory. Thinking about your posture is not enough to correct your imbalances and even if you could, what happens to your posture when you get distracted?
Myth #2: This is the way I was born; It's just the way I am.
Truth: Postural alignment is not genetic. As much as you'd like to blame your parents for your bowed legs, pronated feet, rounded upper back, or forward head, that argument just doesn't carry any weight. Your postural alignment is a reflection of how you've moved throughout your life, not your DNA.
Myth #3: Good posture means a flat stomach.
Truth: Good posture means a relaxed stomach. Tightening or pulling in your abdominal muscles causes many problems including increased risk of low back injury, interference with hip and pelvic movements, compromised breathing, increased neck, shoulder, and upper back tension, and deceased mood.
Truth: Strengthening your core will strengthen or "lock in" your current postural alignment - which is probably not very good. Most people with poor posture and who are looking at core strengthening as a way to improve their posture have some kyphosis and shoulder rounding along with a hip disparity, and strengthening their core will only cause these imbalances to get worse. Core strengthening is best left for after you have good postural alignment, not before. This principle is easily remembered by the phrase: straighten before you strengthen.
Truth: Yes, almost everyone you look at around you probably looks much different posturally from each other, but that does not mean their posture is designed to be different. We all share the same bones, joints, muscles, ligaments, and nerves and they are designed to align themselves in the same way. The differences you see in people's postures are environmental (how they use their bodies) not genetic.
Truth: Research and many experts have been talking about the dangers of valgus knees and medially rotated femurs and how that increases the chance of an ACL tear. Many of these experts then reason that if valgus and medial rotation is bad, varus and external rotation must be good. In philosophy 101 we learned this is a false dilemma...apparently many posture experts skipped philosophy class! Knees that are vertically aligned with the ankles and hips and that point straight ahead are natural and function best and any misalignment can and will cause inefficiency in movement, tissue damage, and pain eventually.
Myth #7: Good posture means tucking your chin and lengthening your neck.
Truth: People who say this are trying to correct forward head posture and they believe tucking the chin is the way to do that since it does often move the head back. The problem is they are treating the symptom and not the cause. Forward head posture is often caused by some combination of these imbalances: thoracic kyphosis; rounded shoulders; anterior pelvic tilt; posterior pelvic tilt; swayback; flat lumbar spine; lumbar lordosis; and knee hyperextension. Tucking your chin might look better at first glance but without correcting the underlying posture imbalances you've made very little impact on your overall health. Lengthening your neck can decrease the lordosis in the cervical spine too much and put the discs of the neck under increased stress and strain, cause excessive muscle tension, and even restrict your airway (breathing).
Truth: If your pelvis is tilted forward into an anterior tilt, then yes this idea might make sense, but as talked about in myth #1 and #3 postural alignment should come naturally and your stomach should be relaxed. What happens if you give this advice to someone whose pelvis is already tilted backwards into a posterior tilt? You make their posture even worse and greatly increase the chance of low back injury among other things. Not good.
Truth: Good posture means your shoulders are back without you thinking about it. If you are consciously pulling your shoulders back (remember myth #1) you'll create excessive fatigue in your upper back muscles which can cause more pain. Your shoulders should be completely relaxed when standing or sitting and naturally fall into place. If you have to pull your shoulders back to get them aligned with your hips, you need to address the postural imbalances you have throughout the rest of your body, and then your shoulders will fall into place naturally without effort. Any tightening of muscles will lead to poor movement patters and can lead to pain and injury.
Truth: Your knees should be straight when standing relaxed, not bent. Keeping your knees bent while standing increases the pressure on meniscus of the knees and patellar tendon and can cause pain. Hyperextending your knees (locking your knees) by tightening your quads is also stressful to your knees and can create damage to the underside of your patella (kneecap).
Is training your "core" really helping you?
Why you should never pull your stomach in during exercise
8 laws of physical health
10 design perfections in the human body