Controlling the Ground Reaction Force During Lifting.
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.
Toussaint
H. M.
HM
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
Commissaris
D. A. C. M.
DA
Van Dieeumlant;n
J. H.
JH
Reijnen
J. S.
JS
Praet
S. F. E.
SF
Beek
P. J.
PJ