We can think of normal walking as controlled falling. Our body moves forward and a foot moves forward to stop us falling over. In Tai Chi the movement happens the other way. We place the foot forward and then move our weight forward over it. This means we can be sure we are stepping onto firm ground before we commit to it.
This type of stepping requires concentration and awareness as we have had a lifetime of walking automatically, where the weight transfers immediately and with the expectation that we are stepping onto firm ground.
For martial arts, it is an advantage to have the opportunity to change our mind about the direction of a step before we commit to it. In Tai Chi it is very rare that we will have the weight equally across both feet, we are constantly changing from left to right or forward and back.
In everyday life we do not often have cause to walk backwards but for self defence it is useful to be able to do so whilst keeping our balance and controlling the placement of the feet. In Tai Chi we learn to step backwards with awareness, and gain the ability to place the foot behind whilst keeping our weight on the forward foot. We choose whether the foot remains straight or turns outward a little. The alignment of the hips is relevant here if we are keeping our feet straight, and a longer step is more likely to be turned outwards to allow movement in the ankle and comfort when we ‘sit’ into the position.
Whatever the direction of the step we keep the feet at least shoulder width apart and this provides greater stability.
With practice we can apply the principles of Tai Chi walking in normal life, consciously moving the foot before the body. This reduces stress on the joints, ankles, knees and hips, as there is no impact, the heel touches the ground softly and the weight then rolls onto the foot.