研究背景及目的：前十字韌帶重建的運動員會造成膝關節的生物力學運動模式改變，包括步態的適應性改變、脛骨前移、或脛骨外轉角度的增加，這些手術後的運動員在重回運動場之前，需要經過膝關節的檢查與評估以瞭解運動員復原狀況，但是這些評估方式屬於靜態、主觀性或是日常生活動作的評估，無法實際反映出運動員在接受前十字韌帶重建手術膝關節運動員過程中的關節活動情形。因此，本研究的目的在於分析與比較日常生活功能性動作（下蹲、上／下樓梯）與高衝擊性動作（垂直跳、往前跳）在接受前十字韌帶重建手術俊運動員膝關節運動學上的差異。研究方法：不研究共徵召11位接受前十字韌帶重建手術之大學運動員以Zebrls CMS-HS超音波三維動作分析儀進行實驗，測量的動作包括下蹲、垂直跳、件前跳、上樓梯及下樓梯等五個動作。收集並記錄每個動作過程中的最大膝彎曲角度、最大膝外翻、最大膝內翻、最大膝外轉、最大膝內轉、最大膝外轉時之彎曲角度、最大膝外翻時之彎曲角度、最大膝內翻時之彎曲角度，再擷取膝彎曲末端0~3°的膝外翻角度與外轉角度計算關節滑動軌跡路逕長度等九個角度變項。以單因子變異數分析。(One-way ANOVA)及Tukey事後分析比較五種動作（下蹲、垂直跳、往前跳、上樓梯、下樓梯）在前十字韌带重建之運動員的膝關節九個角度燮項之運動學差異。結果：前十字韧帶重建組運動員在五種功能性動作之比較結果顯示，在膝關節最大彎曲及關節滑動軌跡長度兩個運動學變數有顯著差異(p<.05)，其餘變數均無顯著差異。其中，下蹲動作有最大的膝關節彎曲(111.4±16.8°)。往前跳動作的膝關節彎曲角度最小(73.1°±19.9°)。在關節滑動軌跡長度中，往前跳動作與下蹲、垂直跳、上樓梯及下樓梯動作均有顯著差異(p<0.5)，其中，以往前跳最長(1.2±0.5)，上樓梯及下蹲動作最少(0.5±0.1)。結論：由研究之結果顯示往前跳動作在五個功能性動作中，具有最少的膝關節彎曲角度及最長的關節活動軌跡路径，與其他四種動作（下蹲、上／下樓梯、及垂直跳）在膝關節運動學變數上有明顯的區別，因此比其他四種動作適合作為運動員回運動場之前的指標。

Background: Recent research suggests athletes after anterior cruciate ligament (ACL) reconstruction leads to alterations in gait adaptation, tibial anterior/posterior translation, and tibial external rotation. Before return the athlete to their previous sports level, there were needs to evaluate the recovery of knee joint after ACL reconstruction surgery. Most of evaluated methods were static clinical tests, questionnaires of knee functions. Of lower impacted activities analysis. It did not reflect the real joint kinematics of knee after ACL reconstruction in high impacted activities. Objective: The aim of this study was to compare the knee kinematics among lower impacted movements (squart and up/down stair) and high impacted activities (vertical jump and hop) for athletes with anterior cruciate ligament reconstruction. Methods: The study was conducted on 11 collegiate athletes following ACL reconstruction surgery. Knee kinematics analyses were performed by applying the Zebris three-dimensional ultrasound-based system during squatting, up-and down-stair, vertical jump and hop. One-way ANOVA and Turkey post hoc comparison were used to examine the differences among 5 movements in athletes with ACL reconstruction. Results: Hop movement exhibited a less angle of maximal knee flexion and a longer length of joint excursion in contrast with others movements in athletes with ACL reconstruction. Conclusion: Hop movement could be used as a predictive factor to evaluated recovery of knee kinematics for athletes with ACL reconstruction.