The purpose of this study was to construct an estimated equation that would reveal the relationship during walking between supporting time obtained by analysis of ground reaction force and walking speed, step length and cadence obtained by image analysis. Five healthy young men, five healthy elderly men, six healthy young women, and twenty healthy middle aged women participated as the subjects in this study. The data of the force plate at stance phase were analyzed in synchronization with the image data during walking. The following results were obtained:
1. It was indicated that walking speed, step length and cadence can be determined only by the data of supporting time obtained through analysis of ground reaction force, given the linearized relationship between walking speed and step length, and that between supporting time and step duration. Furthermore, the precision of estimation can be improved by including the effect of height.
2. The validity of the above estimated equation was evidenced as a consequence of verification with a different group (ten healthy young men and ten healthy elderly men).
3. The following were the estimated equations obtained from all the data including those used for verification. These equations determine walking speed (v) , step length (l) and cadence (ca) by supporting time (tsup) and height (ht).
v = 60 (bht + c)/(dtsup + e - 60a)
l = 60a (bht + c)/(dtsup + e - 60a) + bht + c
ca = 60/(dtsup + e)
provided that a = 0.004092, b = 0.001579, c = 0.091408, d = 0.707010, e = 0.065543
In conclusion, it may be shown that the estimated equation in this study was able to estimate with high precision within the limits of application.
