Centre of pressure displacement during walking in subjects with low back pain: a vector field statistical analysis

To observe differences in centre of pressure (COP) trajectories of 15 low back pain subjects during gait at three different walking speeds, a vector field statistical analysis was conducted. Medial-lateral COP showed medialisation (1) at fast walking speed, at transition between shock absorption phase and forefoot loading and at propulsion phase and (2) at preferred walking speed, at maximal load or 50% of stance phase. The latter tendencies could not be corroborated by vector field analysis. Future studies, considering the new features of open source software spm1d, should re-examine the data, which differed from those found in normal subjects.