Analysis of the multi-segmental postural movement strategies utilized in bipedal, tandem and one-leg stance as quantified by a principal component decomposition of marker coordinates

Abstract

This file was dowloaded from the institutional repository Brage NIH -brage.bibsys.no/nih Federolf, P., Roos, L., Nigg, B. (2013) AbstractPostural control research describes ankle-, hip-, or multi-joint strategies as mechanisms to control upright posture. The objectives of this study were, first, development of an analysis technique facilitating a direct comparison of the structure of such multi-segment postural movement patterns between subjects; second, comparison of the complexity of postural movements between three stances of different difficulty level; and third, investigation of between-subject differences in the structure of postural movements and of factors that may contribute to these differences.Twenty-nine subjects completed 100-second trials in bipedal (BP), tandem (TA) and one-leg stance (OL). Their postural movements were recorded using 28 reflective markers distributed over all body segments. These marker coordinates were interpreted as 84-dimensional posture vectors, normalized, concatenated from all subjects, and submitted to a principal component analysis (PCA) to extract principal movement components (PM). The PMs were characterized by determining their relative contribution to the subject's entire postural movements and the smoothness of their time series.Four, eight, and nine PM were needed to represent 90% of the total variance in BP, TA, and OL, respectively, suggesting that increased task difficulty is associated with increased complexity of the movement structure. Different subjects utilized different combinations of PMs to control their posture. In several PMs, the relative contribution of a PM to a subject's overall postural movements correlated with the smoothness of the PM's time series, suggesting that utilization of specific postural PMs may depend on the subject's ability to control the PM's temporal evolution.3

Does outstretching the arms improve postural stability?

“…Honegger et al [4] provide supporting evidence for this latter concept in that their participants voluntarily adopted the arms down posture in this condition, only outstretching the arms when conditions became more difficult. Also, arm movement (hands on hips) contributed less than 10% of the variance in tandem stance with eyes open in the study by Federolf et al [1]. The increased spectral power in the force data with eyes open could reflect the larger forces generated [10])…”

Assessment of Postural Stability in Young, Physically Active Men With the History of Ankle Sprain

“…The difference of mean sway velocity was also statistically insignificant (p=0.09). The difference was bigger in the group of patients with the history of ankle sprain (18 W te ście Y -Ba lan ce Test naj więk szą ró żni cę mię -dzy śred ni mi wy ni ka mi obu grup od no to wa no dla kierun ku się gnię cia tyl no -bocz ne go (PL -%MAXD), któ ra w gru pie kon tro l nej by ła o 5,34% wy ższa niż w grupie ba da nej (GB -108,34%, GK -114,13%). Ró żni ca ta nie oka za ła się jed nak istot na sta ty stycz nie.…”

“…Od po wiedź ta po le ga na ta kim usta wie niu cia ła, że by nie za le żnie od po zy cji je go śro dek cię żko ści po zo sta wał za wsze po nad płasz czy zną pod par cia [17,18]. U osób zdro wych, za utrzy ma nie sta bil nej po sta wy cia ła w swo bod nej po zy cji sto ją cej za rów no obu nóż, jak i jed no nóż odpo wia da tzw.…”

“…Such a response involves assuming a body position so that the gravity center was always beyond the base of support [17,18]. In healthy individuals the so called "ankle joint strategy" or distal-proximal strategy, is responsible for maintaining body stability in a free standing position, either on both legs or on one leg [10,19,20].…”

“…za kre su ru chu w sta wach, ela stycz no ści i si ły mię śnio wej oraz kontro li ner wo wo -mię śnio wej [18,[24][25][26]35]. Lee wy ka zał zale żność mię dzy si łą pro stow ni ków i od wo dzi cie li sta wu bio dro we go oraz zgi na czy i pro stow ni ków stawu ko la no we go a wy ni kiem te stu Y -Ba lan ce w trzech oce nia nych kie run kach, w gru pie osób z prze wle kłą nie sta bil no ścią sta wu sko ko wo -go le nio we go [24].…”