L'initiation de la marche correspond à la période transitoire comprise entre deux états stationnaires, la posture debout et le mouvement de marche établie. Il s'agit d'un acte intentionnel qui nécessite le passage du corps d'un état quasi statique à un état dynamique.

Gait initiation is the transient period between upright posture and steady state gait. It is an intentional movement during which the postural programme gives way to the locomotor programme. Its central programming has to take into account the outer constraints (coming from the environment) as well as the inner constraints (coming from the body itself), implying complex interactions between biomechanical and neurophysiological factors.