緒論：外側踝關節扭傷是常見的運動傷害，主要發生在反覆跳躍與側向移動的著地過程，而反覆扭傷患者可能發展成慢性踝關節不穩定族群，過去對於踝關節不穩定的相關研究，常探討健康人與不穩定族群間的差異，鮮少針對曾扭傷但踝關節未出現不穩定族群的比較。因此，本研究以連續側向跳著地動作評估健康組、潛在組與不穩定組運動員的著地模式，主要觀察三個族群在功能性著地動作的關節運動特徵。方法：招募30位大專運動員，以Cumberland踝關節不穩定問卷，輔以理學檢測區別不同踝關節型態，以單腳連續側向跳著地測試，跳躍距離標準化以實驗參與者髂前上棘兩側距離的210%，利用10台Vicon紅外線攝影機（200 Hz）與2塊Kistler測力板（1000 Hz）同步收集著地階段的運動學與地面反作用力資料，統計方法使用混合設計二因子變異數分析，比較不同著地方向與組別間的下肢力學參數。結果：下肢的髖、膝與踝關節角度在不同組別間的比較未有顯著差異，惟不穩定組的踝關節活動範圍顯著小於健康組，但在不同著地方向中，內側著地的髖、膝與踝關節角度顯著高於外側著地，顯示額狀面關節角度變化受著地方向的影響甚深。結論：不穩定組的踝關節背屈活動度受限，促使踝關節的減震緩衝能力降低，進而有較大的垂直地面反作用力峰值，而潛在組踝關節運動狀態介於健康組與不穩定組之間的特徵，最後，著地方向具有影響額狀面的關節運動模式，外側著地使用髖關節額狀面策略提供姿勢穩定的維持，而內側著地使用較多的踝關節額狀面策略，可能大幅增加再次扭傷風險。

Introduction: Ankle sprain was one of the most common sports injuries, which is often occurs at the repeated jumps and lateral movement of the landing phase. Recurrent ankle sprain may develop into chronic ankle instability (chronic ankle instability, CAI). Most previous studies of ankle instability investigated differences between CAI and healthy subjects, but few studies have emphazied on those who had sprined ankles but without mechanical or pathalogical symptoms (ankle sprain coper, Coper). The objective of this study was to evaluate the continues side hopping and landing patterns in CAI athletes, Coper athletes, and healthy athletes. We focus on using functional movements to analyze the motion differences between these three groups. Methods: There were 30 collegiate Division I athletes (10 healthy control, 10 Copers, and 10 CAI who were sex, age, height, and weight matched with healthy control) volunteered in this study. All groups need to fill the Cumberland Ankle Instability Tool (CAIT) for grouping. All participants performed a side-to-side hopping task that consisted of hopping single-legged 4 times consecutively from side to side across 2 lines marked apart on 2 individual force plates. The hoping distance was normalized by 210% of individual's ASIS distance. Kinematics and kinetics data were collected by 10 Vicon infrared cameras at 200 Hz and two Kistler force platforms at 1000 Hz. Two-way mixed analysis of variance (ANOVA) was used to compare the difference of biomechanics parameters between the direction of landing and groups. The level of statistical significance was set at α ＜ .05. Results: There was no significant difference in joint kinematics among groups during both medial and lateral side hopping. The healthy group showed significantly greater ROM of ankle joint compared to the CAI group. When landing on medial side, joint angles of ankle plantar flexion, knee flexion and hip flexion were significantly greater than landing on lateral side. In addition, joint kinematics of frontal plane were significantly affected by landing directions. Conclusions: In this study, we found CAI group was limited with ankle dorsiflexion angle, which reduces shock attenuation of ankle joint, and thus has a large vertical ground reation force. The ankle joint status of Coper was between healthy and CAI groups. However, landing directions could influence kinematics patterns in frontal plane entirely. Landing from lateral hopping, maintained posture stability by hip abduction and adduction angles, though landing from medial hopping utilized ankle inversion and eversion angles. That might be the reason of re-injury in CAI and Copers.