title: The formation of trajectories during goal-oriented locomotion in humans. I. A stereotyped behaviour.
abstract: Human locomotion was investigated in a goal-oriented task where subjects had to walk to and through a doorway starting from a fixed position and orientation in space. The door was located at different positions and orientations in space, resulting in a total of 40 targets. While no specific constraint was provided to subjects in terms of the path they were to follow or the expected walking speeds, all of them generated very similar trajectories in terms of both path geometry and velocity profiles. These results are reminiscent of the stereotyped properties of the hand trajectories observed in arm reaching movements in studies over the last 20 years. This observation supports the hypothesis that common constraining mechanisms govern the generation of segmental and whole-body trajectories. In contrast, we observed that the subjects placed their feet at different spatial positions across repetitions, making unlikely the hypothesis that goal-oriented locomotion is planned as a succession of steps. Rather, our results suggest that common planning and/or control strategies underlie the formation of the whole locomotor trajectory during a spatially oriented task.
authors.affiliation: Laboratoire de Physiologie de Perception et de l'Action, Collège de France CNRS UMR7152, 11 place Marcelin Berthelot, 75005 Paris, France. halim.hicheur@college-de-france.fr
authors.forename: Halim
authors.initials: H
authors.lastname: Hicheur
authors.forename: Quang-Cuong
authors.initials: QC
authors.lastname: Pham
authors.forename: Gustavo
authors.initials: G
authors.lastname: Arechavaleta
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Laumond
authors.forename: Alain
authors.initials: A
authors.lastname: Berthoz
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D006040:Goals; D006801:Humans; D007699:Kinesthesis; D008124:Locomotion / Q000502:physiology*; D008297:Male; D009068:Movement / Q000502:physiology; D009949:Orientation / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D013037:Spatial Behavior / Q000502:physiology*; D013239:Stereotyped Behavior / Q000502:physiology*; D013997:Time Factors