Background: The main objective of the present study is to investigate the relationship between the principal components (PCs) of the sagittal kinetic variables in the lower limb and the ground reaction forces (GRFs) during gait in patients with hemiparesis. Methods: We recruited 21 patients with hemiparesis and 12 healthy controls. The 3-dimensional (3-D) coordinates of 33 markers were measured with a 3-D motion analysis system operating at 120 Hz and force plates as the subjects walked along a 7-meter walkway. The correlation coefficients between the over-time series of PCs, which is calculated using principle component analysis (PCA), and GRFs were compared among the left side of the controls and the paretic side (PS) and non-PS of the patients by using analysis of variance (ANOVA). Results: The correlation coefficient of the non-PS between the first PC and GRF in the anteroposterior-direction was significantly higher than that on the PS (P < 0.05) and that of the non-PS in the vertical-direction was lower than the PS (P < 0.05). Conclusions: The results indicated that intralimb kinetic coordination on the PS plays an essential role in weight support in patients with hemiparesis, whereas the kinetic coordination on the non-PS plays a role in generation of propulsion.
gait, ground reaction forces, hemiparesis, intralimb kinetic coordination, lower limbs