title: Absence of center of mass control for leg abduction in long-term weightlessness in humans.
abstract: The present investigation describes for the first time leg lateral abduction performance during long-term microgravity exposure. Two astronauts took part in the experiments, starting 2 weeks into the mission and lasting for 5 months. Results on joint angles kinematics confirm previous investigations on parabolic flights, showing good task fulfillment for both subjects. Special interest was focused on whole body center of mass (CM) positioning. As in short-term microgravity, no initial CM lateral shift toward the 'supporting' leg was observed. In contrast with short-term microgravity and ground-based experiments, no stabilization of the CM medio-lateral position was found but a significant shift of CM toward the moving leg was observed. This suggests that the adaptation to sustained weightlessness might have led to a microgravity-specific motor strategy for leg abduction, which was not focused on CM strategy.
authors.affiliation: Department of Bioengineering, Politecnico di Milano, Piazza Leonardo da Vinci, 33, 20133 Milan, Italy. pedrocchi@biomed.polimi.it
authors.forename: Alessandra
authors.initials: A
authors.lastname: Pedrocchi
authors.forename: Guido
authors.initials: G
authors.lastname: Baroni
authors.forename: Laurence
authors.initials: L
authors.lastname: Mouchnino
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Ferrigno
authors.forename: Antonio
authors.initials: A
authors.lastname: Pedotti
authors.forename: Jean
authors.initials: J
authors.lastname: Massion
mesh_terms: D000328:Adult; D006801:Humans; D007866:Leg / Q000502:physiology*; D008297:Male; D009068:Movement / Q000502:physiology*; D013997:Time Factors; D014893:Weightlessness