Post-effect of forward and backward locomotion on body orientation in space during quiet stance

Neural circuits responsible for stance control serve other motor tasks as well. We investigated the eVect of prior locomotor tasks on stance, hypothesizing that postural post-eVects of walking are dependent on walking direction. Subjects walked forward (WF) and backward (WB) on a treadmill. Prior to and after walking they maintained quiet stance. Ground reaction forces and centre of foot pressure (CoP), ankle and hip angles, and trunk inclination were measured during locomotion and stance. In WF compared to WB, joint angle changes were reversed, trunk was more Xexed, and movement of CoP along the foot sole during the support phase of walking was opposite. During subsequent standing tasks, WB induced ankle extension, hip Xexion, trunk backward leaning; WF induced ankle Xexion and hip extension. The body CoP was displaced backward post-WB and forward post-WF. The post-eVects are walking-direction dependent, and possibly related to foot-sole stimulation pattern and trunk inclination during walking.