This investigation identifies the center of pressure (COP) progression characteristics under the plantar region for elderly adults during barefoot walking. A total of 60 healthy adults (30 young and 30 old) were recruited. The young and elderly participants had average ages of 23.6 (SD=2.7) and 70.8 (SD=4.1) years old, respectively. All subjects had normal foot arch and no relevant musculoskeletal disease in the lower extremities. The foot pressure measurement system (RS-scan(®) system) was used to measure the center of pressure coordinates (COP), progression angle and COP velocity. Four sub-phases of the stance phase were calculated. The initial contact (ICP) and forefoot contact phase (FFCP) corresponded to the loading response. The foot flat phase (FFP) coincided with the mid-stance. The forefoot push-off phase (FFPOP) corresponded to the terminal stance and pre-swing phases. The analytical results revealed that age effects were found in the relative time percentages for the initial contact, foot flat and forefoot push-off phases during foot movement. The elderly subjects exhibited significant medial COP curve and faster COP velocity during the initial contact phase and more pronated mid-foot posture and slower COP velocity during the mid-stance. The older adults tended to have a more pronated foot and displayed a significant medial COP curve compared to young adults. These COP progression characteristics can provide further insight into relevant foot function and gait performance evaluations for older adults.
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