Spatiotemporal Evolution of Toddlers' Regional Foot Pressure Distribution and Center of Pressure at Antero-Posterior Axis During Learning of Standing.

We investigated quiet stance of newly standing infants every three months (trimesters) of their second year of life. Their anteroposterior Center-of-Pressure (CoPx) velocity and centroidal frequency (CFREQ: 2.36±0.10 to 1.50±0.11 Hz) decreased over time. Besides, mean pressures revealed a potential role-sharing of foot regions in learning and control aspects of standing, with hindfoot carrying the highest (23.89±6.47 kPa) pressure while forefoot the lowest (10.26±2.51 kPa). The highest CFREQ of pressure signal was at mid-foot. Through regional CoPx, forefoot has manifested the highest CFREQ (2.10±0.40 Hz) and 90% power frequency (90%PF), whereas hindfoot presented the lowest (CFREQ: 1.80±0.33 Hz). CFREQ and 90%PF of both pressure and regional CoPx significantly decreased at each region throughout all trimesters.