The best walking posture is one in which the body is kept in a balanced, relatively straight position, where the spine is not curved too far forwards or backward. It is important to monitor the entire body while walking. Make sure that the chin is up, the shoulders are relaxed, the spine is straight, and the feet are striking the ground first with the heel, and then rolling towards the toe. Maintaining a proper neutral walking posture will help to prevent injury and ensure that one gets as many physical fitness benefits as possible from the exercise.
People often think that in order to have perfect walking posture, the spine should be ramrod straight. This is not true; in fact, a more neutral posture that allows slight curves in the spine is actually better for the body. Ideally, the ears, shoulders, and hips should remain in a relatively straight line when walking, but there can be a slight inward curve in the lower back. It is important not to bend backward or forwards, however, when trying to maintain proper posture; there is no need to force the spine into perfectly straight alignment. Slightly tightening the abdominal muscles and tucking the tailbone under will help to engage the abdominals when walking and improve posture in everyday life, not just when exercising.
In ideal walking posture, one should not be looking down at the ground, which can stretch the back of the neck and lead to pain. Instead, keep the chest lifted, chin up, and eyes forward. Regularly shrug the shoulders to be sure that there is no tightness there. Many people find that bending the arms at the elbows, and swinging them with each stride, helps to exercise the arms as well as helping them maintain proper posture. It is not recommended that one carry hand weights, which can stretch the tendons in the arms.
Finally, the stride is important in maintaining good walking posture as well. The stride length should be natural; it is better to take shorter, quicker strides than to try to take large strides and potentially pull a muscle and put the spine at an unnatural angle. The heel should strike the ground, then roll to the toe for each step. It is important to wear good, supportive walking shoes to maintain good walking posture and to prevent the feet from rolling to one side or the other.