title: A stricter condition for standing balance after unexpected perturbations.
abstract: In order to account for the dynamic nature of balance, the concept of the 'extrapolated centre of mass' XcoM has been introduced (Hof et al., 2005). The law for standing balance was then formulated as: the XcoM should remain within the Base of Support (BoS). This law, however, does not take into account that the centre of pressure (CoP) needs time to displace due to various neural and mechanical delays. The theory is extended to include the finite reaction- and displacement time of the CoP. Experimental results on humans standing on two feet undergoing sudden postural perturbations are presented. In this case it turns out that the area of the effective BoS is only a fraction, some 30%, of the area of the static BoS.
authors.affiliation: Centre for Human Movement Sciences, University of Groningen, The Netherlands; Centre for Rehabilitation, University Medical Centre Groningen, The Netherlands. Electronic address: a.l.hof@umcg.nl.
authors.forename: At L
authors.initials: AL
authors.lastname: Hof
authors.affiliation: Centre for Rehabilitation, University Medical Centre Groningen, The Netherlands; Department of Neurology, School of Medicine, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Carolin
authors.initials: C
authors.lastname: Curtze
mesh_terms: D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D011312:Pressure
keywords: Balance; Base of support; Centre of mass; Centre of pressure; CoM; CoP; Equilibrium; XcoM