Good Posture is when your muscles, bones and joints are in the correct alignment, so that muscles are being used properly and to their maximum efficiency, which means not only will you have more power and control, but it also reduces the possibility of headaches and back pain in general, and avoids many other common ailments.
This means that the bones, muscles and the items that connect them all together – the tendons and ligaments – are in their natural and intended positions.
The best posture is always the one in which all body segments are balanced in the position of optimal alignment and maximum support, with full mobility possible.