Center of pressure path during Sit-to-walk tasks in young and elderly humans

This study aimed to investigate differences in total center of pressure (TCOP) paths during a Sit-to-Walk task in young and elderly subjects.

Nine young and 19 elderly subjects were asked to repeat five Sit-to-Walk tasks. The COP paths were computed during the rising from vertical forces.

For 4 young and 17 elderly subjects, the TCOP moved on the anterior-posterior axis during the 1st period (from the beginning of the rising to maximal force under the swing leg) and then joined the stance foot during the 2nd period (from maximal force to the toe off). For the two other paths observed in young subjects, the duration of the 2nd period was increased (33% of total duration vs. 18%, P = 0.02) or the area of TCOP displacement during the 1st period was decreased.

During the Sit-to-Walk task, different TCOP paths can be described in relation to age. These profiles are influenced by the level of postural stability required before initiating the first step. After further validation, the analysis of TCOP paths could be used to estimate the level of postural ability, especially in the elderly.