目的：藉由三維動作分析系統瞭解赤足及穿著羽球鞋時，側步動作之運動學分析，以作為未來足部功能評估及羽球鞋功能性開發之依據。方法：以10位大專男子羽球選手為受試者，進行赤足與穿著羽球鞋的側步動作，測量三維空間中足踝關節轉動、水平面蹠骨關節角度與矢狀面內側縱向足弓與拇趾角度變化。由10臺紅外線攝影機(240 Hz)擷取足部15顆反光球建立下肢足部模型剛體參數，並以統計軟體SPSS成對樣本t檢定分析2種情況下的側步動作模式差異。結果：赤足的背屈角度顯著大於穿著羽球鞋(p < .05)，穿著羽球鞋的後足內翻角度顯著大於赤足(p < .05)。在水平面外側蹠骨與矢狀面拇趾量測的角度，赤足都比穿著羽球鞋有顯著較大的活動範圍(p < .05)。結論：羽球選手進行側步動作時，踝關節有較大的內翻角度，使得外側扭傷的風險相對較高；赤足的拇指活動度，比穿著羽球鞋有較多的屈曲情形。為了達到最佳化的羽球鞋功能設計，鞋面設計建議符合赤足所量測的關節角度。

Purpose: To analyze the three-dimensional foot kinematics under barefoot and badminton shoe conditions during the stance phase of side step movement. The results of this study could be used to evaluate foot function and create new functional badminton shoes in the future. Methods: Subjects were 10 college male badminton players. Comparison of side step with barefoot and badminton shoes conditions was conducted to evaluate angle changes in three-dimensional joint motion of metatarsus, lateral metatarsal bones angle in transverse plane and medial longitudinal arch and hallux angle in sagittal plane. Trajectory data were collected from 15 markers by 10 motion capture system cameras at 240 Hz. The paired t-test was used for statistical analysis using SPSS software. Results: There were significantly higher dorsi-flexion and inversion angles in ankle joint under badminton condition (p < .05). Furthermore, the results also found significantly higher range of motion in side metatarsal bone in transverse plane (p < .05), and significantly higher hallux angle motion in sagittal plane under barefoot condition (p < .05). Conclusions: The results of this study showed that the risk of lateral ankle sprain is relatively higher in side step movement due to the larger inversion angle. Furthermore, the M1Ps (hallux) is more active and has more flexion in barefoot than in wearing badminton shoes. In order to design the optimal badminton shoes, the range of motion under barefoot conditions should be considered in upper shoe parts design.