Search results for "Horizontal axis"
showing 3 items of 3 documents
Standing up from a chair as a dynamic equilibrium task: a comparison between young and elderly subjects.
2000
The purpose of this study was to analyze and compare the features of center of mass (CoM) control along anterior/posterior axis in young and elderly subjects during sit-to-stand (STS). From a sitting position, seven healthy young subjects and seven healthy elderly subjects were asked to stand up from a chair under different experimental conditions (visual conditions: normal and blindfolded; speed: normal and as fast as possible). Analysis of results was based upon the concept of a “dynamic equilibrium area” (DEA), which in turn identified the dynamic limits of balance. The results showed that both the maximal CoM velocity in the horizontal axis and the CoM velocity at the instant of seat-of…
Superintendent Leadership in Hierarchy and Network
2015
School superintendents are coupled hierarchically with the top apex of municipality organization through their membership of leadership teams and through personal ties to the top municipal manager, which provides opportunities to take part in strategic decision-making processes beyond the educational sector. Superintendents are also vertically linked to their school leaders through strong and dense network ties. Along the horizontal axis superintendents are active network players with peers, for example through superintendent associations or more frequently mentioned through personal ties to superintendent colleagues. Superintendents are linked to school boards through strong formal ties. I…
Does the centre of mass remain stable during complex human postural equilibrium tasks in weightlessness?
2001
In normal gravity conditions the execution of voluntary movement involves the displacement of body segments as well as the maintenance of a stable reference value for equilibrium control. It has been suggested that centre of mass (CM) projection within the supporting base (BS) is the stabilised reference for voluntary action, and is conserved in weightlessness. The purpose of this study was to determine if the CM is stabilised during whole body reaching movements executed in weightlessness. The reaching task was conducted by two cosmonauts aboard the Russian orbital station MIR, during the Franco-Russian mission ALTAIR, 1993. Movements of reflective markers were recorded using a videocamera…