Analysis of Impact Force on Runner’s Foot during Stance Phase

The aim of this research is to analyze the effect of two types of running shoes on runner’s foot during stance phase, using two force plates equipped with specified track board. The main method that will be discussed in this paper is system design of gait analysis with the specific setting, in order to acquire ground reaction force (GRF) data. Then we use that experimental data to calculate the impulse during stance phase using Trapezoidal rule. The benefit of this study is to provide information and new ideas about running and its prevention over an injury. When observed from the bar chart of the maximum GRF normalized to body weight value of the four subjects using each of the R, M, and B shoe soles, it seems that when the four subjects used footwear with R (Reg) sole shoe, the subject experienced the maximum force (i.e. 2.9 by the 3rd subject) compared when using shoe sole M (Run), or barefoot B (Bare). Whereas when the subject does not use footwear (B), they did not experience a significant difference when compared with the subject of wearing footwear with shoe sole M. That also means when the 3rd subject stands still above the force plate, it generated the force output of the gravity or the weight of the subject (the average body weight of 3rd subject is 529.2 N). The ratio of the force gain experienced by the foot of the 3rd subject during the stance phase can reach up to 2.9 times compared to when she stood still. Total impulse that were experienced by the 4th subject during stance phase are the summation of those two integrals (199.22 N.s and 190.52 N.s). The measurement of foot impulse on stance phase using Trapezoidal Rule is the approximation by integrating the area under the curve in the form of polynomial function. From the impulse data that were obtained, that have not the clear correlation between sole shoes were worn with the foot impulse on stance phase.