著地急停與反彈跳著地期下肢運動學與地面反作用力之比較

Lower Extremity Kinematics and Ground Reaction Forces of Drop-Stop and Drop-Jump Tasks during the Landing Phase

目的：本研究欲探究急停與急停跳，此兩種運動中常見的急停著地形態，其著地動作與地面反作用力之差異，以了解其下肢負荷之特性。方法：收集14名自願參與本研究之大學體育系男性學生著地階段的下肢運動學與地面反作用力資料。每位受試者皆進行兩種40公分高台著地動作的測試：1.著地急停；2.著地反彈跳。以八台光學攝影機 (200 Hz) 與兩塊三軸測力板 (1000 Hz) 同步進行資料的擷取。以The Motion Monitor軟體進行資料處理。利用 SPSS 統計軟體進行相依樣本t-test，統計顯著水準定為α=.05。結果：研究結果顯示，相較於急停跳動作而言，急停動作於觸地瞬間的踝、膝與髖關節屈曲角度較少，著地期的踝、膝與髖關節最大屈曲角度亦較小，且著地期會形成較大的地面反作用力與負荷率。結論：進行急停動作時下肢的著地動作較為挺直，且會形成較大的著地撞擊，此會增大前十字韌帶的負荷，故急停動作會有比急停跳動作大的下肢傷害風險。

Purpose：This study was dedicated to the investigation on the differences of landing movements and ground reaction forces between drop-stop and drop-jump tasks in order to provide further information on the lower extremity loading in these skills. Methods: Ground reaction forces, and lower extremity kinematics data during the landing phase were obtained from 14 male college students from the department of physical education voluntarily participated in the study. Two types of drop-landing tasks, drop-stop and drop-jump from 40 cm, were performed. Kinematics and ground reaction forces data were synchronized and collected by using eight cameras (200 Hz) and two force palates (1000 Hz). Data were then analyzed via the Motion Monitor analysis software. The t-test performed by SPSS was used to test for differences in dependent variables between the drop-stop and drop-jump. The significance level was set at α = 0.05. Results: Our research findings indicate that the ankle-knee-hip flexion angle at the initial foot-ground contact and the peak flexion angle during landing were significantly smaller in the drop-stops in comparison to those in the drop-jumps. In addition, the drop-stops demonstrated significantly greater peak ground reaction forces and loading rates during landing compared to those of drop-jumps. Conclusions: In short, the movements of lower extremity were straighter in the drop-stop tasks than those in the drop-jump tasks, which, in turn, caused greater impact forces and consequently led to increased ACL loadings. To sum up, based on our research findings, it can be inferred, with fair certainty, that drop-stop tasks illustrated a higher risk of lower extremity injury than that in the drop-jump tasks.