Biomechanical analysis of the stance phase during barefoot and shod running

This study investigated spatio-temporal variables, ground reaction forces a nd sagittal and frontal plane kinematics during the stance phase of nine tr ained subjects running barefoot and shed at three different velocities (3.5 , 4.5, 5.5 m s(-1)). Differences between conditions were detected with the general linear method (factorial model). Barefoot, running is characterized by a significantly larger external loading rate than the shed condition. T he flatter foot placement at touchdown is prepared in free flight, implying an actively induced adaptation strategy. In the barefoot condition, planta r pressure measurements reveal a flatter foot placement to correlate with l ower peak heel pressures. Therefore. it is assumed that runners adopt this different touchdown geometry in barefoot running in an attempt to limit the local pressure underneath the heel. A significantly higher leg stiffness d uring the stance phase was found for the barefoot condition. The sagittal k inematic adaptations between conditions were found in the same way for all subjects and at the three running velocities. However, large individual var iations were observed between the runners for the rearfoot kinematics. (C) 2000 Elsevier Science Ltd. All rights reserved.