Center of pressure progression characteristics under the plantar region for elderly adults

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.