title: Effects of support surface and optic flow on step-like movements in pre-crawling and crawling infants.
abstract: Step-like movements were examined in pre-crawling (n=9) and crawling (n=9) 6-13 month-old infants in the air and on a surface in response to a static pattern or optic flows that moved toward or away from the infant. Infants completed six 60-s trials. A significant interaction between locomotor status and support condition revealed that pre-crawling infants made more step-like movements in the air than on a rigid surface. In contrast, crawling infants made an equivalent number of step-like movements in the air and on the surface. Optic flow did not influence the number of step-like movements made by infants. The pre-crawling infant finding is consistent with a finding in a previous study in which two month-old infants were shown to step more in the air than on the ground. This finding is discussed relative to the idea that the infant stepping pattern disappears because the legs become too heavy to lift.
authors.affiliation: Department of Kinesiology, San Francisco State University, San Francisco, CA, United States. Electronic address: danders@sfsu.edu.
authors.forename: David I
authors.initials: DI
authors.lastname: Anderson
authors.affiliation: Department of Kinesiology, San Francisco State University, San Francisco, CA, United States.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: Department of Kinesiology, San Francisco State University, San Francisco, CA, United States.
authors.forename: Kate
authors.initials: K
authors.lastname: Hamel
authors.affiliation: Department of Physical Therapy, California State University, Fresno, CA, United States.
authors.forename: Monica
authors.initials: M
authors.lastname: Rivera
authors.affiliation: Institute of Human Development, University of California, Berkeley, CA, United States.
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Campos
authors.affiliation: Laboratoire Psychologie de la Perception-UMR 8242 CNRS-Université Paris Descartes, Paris, France.
authors.forename: Marianne
authors.initials: M
authors.lastname: Barbu-Roth
mesh_terms: D002657:Child Development / Q000502:physiology*; D006801:Humans; D007223:Infant; D007866:Leg / Q000502:physiology; D009068:Movement / Q000502:physiology; D057849:Optic Flow / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D014110:Touch / Q000502:physiology*
keywords: Locomotion; Motor development; Stepping; Vision