title: Controlling the Ground Reaction Force During Lifting.
abstract: The control of the ground reaction force vector relative to the center of gravity (CoG) was examined while subjects performed a back-lifting task. Six male subjects (aged 24.0 +/- 2.5 years) repeatedly lifted a barbell. A biomechanical analysis that used a linked segment model revealed that the summed rotations of body segments during lifting yielded a specific rate of change of the angular momentum of the entire body. This equaled the external moment provided by Fsubg; relative to CoG. This implies that multisegment movements involve control of the angular momentum of the entire body through an appropriately directed Fsubg;. Thus, in dynamic tasks Fsubg; is pointed away from rather than lined up with the CoG, as is the case in static tasks.
authors.affiliation: Department of Health Science, Faculty of Human Movement Sciences, Vrije Universiteit, Van der Boechorststraat 9, 1081 BT Amsterdam, The Netherlands. h_m_toussaint@fbw.vu.nl
authors.forename: H. M.
authors.initials: HM
authors.lastname: Toussaint
authors.forename: D. A. C. M.
authors.initials: DA
authors.lastname: Commissaris
authors.forename: J. H.
authors.initials: JH
authors.lastname: Van Dieeumlant;n
authors.forename: J. S.
authors.initials: JS
authors.lastname: Reijnen
authors.forename: S. F. E.
authors.initials: SF
authors.lastname: Praet
authors.forename: P. J.
authors.initials: PJ
authors.lastname: Beek