What a very, very good question. Some of the answers might surprise you.
Let's start with feeling light. If you're using your back well, you float to your feet from sitting down. There's no sense of effort at all, no loss of balance at any point, no pressure in the neck. Your legs hardly have to work because your lower back and hips are working properly.
You Love to Move
Walking, running and lifting feel light and easy. You want to move because it's such a pleasure to move. You enjoy being out and about, enjoy sports. To have a body and to use it is beautiful. It's what we want and need to do.
You Know What You Need and What You Stand For
If you have a strong back, you have a strong sense of your own needs and you stand up for yourself. You are more resilient than someone with a weak or painful back and less likely to submit to work that is beyond your capacity, or that is likely to injure you. Perhaps this is behind the English language's use of the word “spineless” to mean cowardly or easily swayed.
A Good Back Has Great Stamina and Responds Well to Stress
You have enormous stamina, whether it's for physical activity or for getting the annual report written by Monday. When you have to work hard, the capacity is there. You respond well to stress. But you also know your limits: people with strong backs rarely allow themselves to be injured by overworking.A Good Back is a Good Breather
You can breathe without effort. If your spine is free, strong and flexible, so is your breathing. Your voice will be rich and won't tire easily. (Think of a baby—babies have very good backs, and they use their voices to the limit!—and think how often you've heard a baby get hoarse.)A Good Back is Creative and Energetic, a Good Learner
When you use your back well, you're creative and playful, you learn well. Playfulness comes about because you trust your own sense of balance and can move further from your centre of gravity or your comfort zone without feeling disturbed. Balance comes from a good head-neck-back relationship and gives you confidence in your ability to try something new. You know you will not be unbalanced by new experiences.A Good Back Is Interested and Curious
Your eyes are bright and alert. With a good strong back you don't stagnate or get bored. You're acutely aware of and curious about your surroundings. As my own back strengthened and recovered and I used it better, I began to notice how much fun it was even standing at a bus stop. Standing is fascinating, whether it's listening to and enjoying the subtleties of your own body, or watching and listening to everything around you.A Good Back Means Better Digestion
If your back's strong, you will tend to have good digestion. Look at the picture to the right. If I told you that many people with lower back pain have digestive problems too, would you find that hard to believe? And when something changes in your lower back during an Alexander Technique lesson, stomach rumbling is extremely common.A Good Back is Playful, Carefree and Strong
If your back's strong you can play with your children, throw them up over your head without effort and without pain. As my friend discovered, a bad back doesn't like being bounced on, climbed on or a boisterous five-year-old suddenly launching himself at you. A good back laughs it off.A Good Back is Good for Birthing and Parenting
You can give birth, not without pain, but with greater ease and without injury. One reason is that, if you're free, flexible and strong in your lower back, it allows your sacrum and tailbone (coccyx) to move out of the baby's way during birth (some birth stories here.) For both men and women, the benefits to parents are obvious: being able to lift your children, throw them around, be jumped on and join in their activities like football, tree climbing, creeping into small spaces. And let's not forget simply coping with non-stop activity from morning til night.A Good Back Reduces Injuries
You are less likely to injure yourself. If you have a strong, flexible back you will be less tense and breakable elsewhere in your body. You'll feel more confident roughing and tumbling. You'll be less subject to repetitive strain injuries because your back is the solid ground out of which your arms and legs grow and they can stay loose and supple. Here's a video of a musician with a beautiful spine, the pianist Artur Rubinstein. Because his spine is strong, see how little effort there is in his hands and arms as he plays a demanding Chopin study.A Good Back Often Goes With Self-Respect
You have respect for yourself and your many abilities. There's a sense of wonder at how dependable, how flexible, how powerful and intelligent your body is. An intelligent body is organised around an intelligent spine.Conclusion
Back pain is extremely common in Australia and other western countries. Many people put up with painful backs because they don't understand that a good back is something you learn, not something you're (usually) born with. Spines have the intelligence to heal beautifully if they're given the smallest chance. The Alexander Technique aims to give a person's spine the chance to recover and take an active, robust part in their lives again.