A Theoretical Study on the Evaluation of the Stability and Postural Sway, Based on the Results of the Confidence Ellipse

The aim of this theoretical study is to compare the results obtained by the confident ellipse with the postural sway identified during the balance test. The ability to control postural balance is an important factor of mobility starting with the performance of daily basic activities to competitive sports. Postural control is the ability to keep the body in an upright position and a good postural stability is needed during daily tasks. Postural sways in different directions, helps in maintaining the body stability. An increase of movements amplitude can lead to equilibrium loss, subsequently falling. This study intends to present a method used for the evaluation of stability through the confident ellipse which has been substituted with the standard ellipse. The theoretical estimation of sway area has revealed that the area of the confidence ellipse strongly depends on the number of points of sway. It is suggested substituting the confidence ellipse with the standard ellipse, which allows the comparison of data collected under different conditions of duration and frequency of postural sway. The results drawn from the confident ellipse, show that 95 % of the figures account for statistical data, which trace the shift of the pressure center as a result of postural sway.