Individual Coordinative Structures During Single-Legged Stance Present Lateral Asymmetry.

Abstract

This work investigated the effect of lateral preference in angular coordination during single-legged postural control, considering individual coordination patterns rather than assuming collective motion modes. Nineteen healthy individuals (8 women), aged between 18-40 years, with a consistent preference for the right side, performed a single-legged stance, while a Vicon System captured data of 39 markers to calculate 30 angles. Two trials of 60s for each lower limb were performed. Principal Component Analysis (PCA) was performed individually for each participant´s data. The involvement of a given angle in the first two principal components (PCs) was evaluated by the zero-lag cross-correlation between the time series of the PC reconstructed in the original 30-dimensional space and the angle time series. A cluster analysis was conducted, based on the Euclidean distances among the loading vectors of the PCs obtained for each support limb. A two-way repeated-measures ANOVA was used to compare the distances. There was no pattern among individuals concerning joints or segments participating in principal modes. The upper body and lower segments participated in the two principal coordination modes. Euclidean distances revealed grouping of PC vectors according to the support of the lower limb. The involvement of joints/segments in the principal movement modes during single-legged stance is highly heterogeneous across individuals. Nevertheless, the coordination strategies differ depending on the support limb.