The ‘cycle’ of action in normal walking is as follows:
- The foot moves forwards (swing phase).
- The foot touches the ground. This is usually first with the heel (initial contact, sometimes called heel strike or foot strike) and then forwards on to the ball of the foot.
- The foot pushes off and leaves the ground again (terminal contact, or ‘foot off’).
The normal foot can flex upwards (dorsiflexion). It can also invert (turn so that the soles tend to face each other) or evert (the opposite of inversion). In foot drop these movements (which occur mainly in heel contact and in the swing phase, are absent. Therefore:
- The swing phase may involve bending the leg at the knee to lift the foot away, rather like climbing stairs.
- The initial contact is not with the feet but with the whole of the foot which ‘slaps’ or plants on to the floor at once
- The ‘foot off’ motion does not function properly at all and a walking stick or cane may be needed to help lift the foot.