In order to calculate the index for the analysis of the cross-arc gait with high accuracy, the server obtains the data of the time change of the angular velocity of the ankle during walking detected by the sensor attached to the ankle of the patient. The time of the swing phase is specified based on the time change of the angular velocity around the X axis. In addition, the server specifies the time from the beginning of the swing phase to the maximum angular velocity around the X axis in the swing phase as the attention time, and calculates it based on the width W of the angular velocity around the Z axis in the attention time An index used to determine whether the patient is performing a cross-arc gait.為了算出用於精度佳地進行跨圓弧步態之分析的指標，伺服器是取得藉由裝附在患者之腳踝的感測機器而檢測到之步行時之腳踝之角速度之時間變化的資料，基於繞X軸轉之角速度之時間變化而特定出擺盪相之時間。又，伺服器是特定出從擺盪相之開頭至在擺盪相之繞X軸轉之角速度成為最大為止之時間來作為著眼時間，基於在著眼時間內之繞Z軸轉之角速度之寬W而算出使用於判定患者是否進行著跨圓弧步態的指標。
