The influence of body configuration on motor imagery of walking in younger and older adults.

Motor imagery (MI) refers to the mental simulation of a movement. It is used as a tool to improve motor function in several populations. In young adults, it has been repeatedly shown that MI of upper-limb movements is facilitated when one's posture is congruent with the movement to simulate. As MI training is notably used for improving locomotor-related activities in older populations, it may be questioned whether subjects' body configuration could also influence MI of walking movements and whether this influence is preserved with age. In the present study, we examined the impact of one's body position (congruent with walking: standing/incongruent with walking: sitting) on the duration of walking simulation over two distances (3m/6m), in 26 young (21 females, 5 males; mean: 23.2 ± 2.4 years) and 26 elderly (18 females, 8 males; mean: 72.7 ± 5.5 years) healthy subjects. It was found that, in both age groups, walking simulation times while standing were shorter than while sitting. Furthermore, walking simulation times in the standing position were closer to actual walking times to cover the same distances. The present findings extend to walking movements the notion that adopting a posture congruent with the movement to imagine facilitates the simulation process. They also suggest that, at least for simple walking tasks, this effect is maintained across the lifespan. The implication of our findings for optimizing MI training of locomotor-related activities is underlined.