目的：本研究之目的為探討，排球運動員連續攔網跳躍過程中，下肢肌電反應與動力學之分析。方法：本研究中招募12名大專優秀男子排球選手為研究參與者，其平均身高為185.5 ± 3.5公分、體重79.5 ± 5.2公分、年齡20.5 ± 1.5歲。受試者在實驗過程中必須進行14次的攔網，其高度設定為個人跳躍高度的90%，共進行三組的測試，組間休息為三分鐘。以10臺Vicon T40動作捕捉系統、Kistler測力板一塊與無線肌電(BTS Free EMG)，收集實驗過程中運動學、動力學與肌電訊號。所有資料皆以MATLAB自行撰寫程式進行資料處理。動力學資料計算每次跳躍中的最大力量峰值、最大發力率與淨衝量。肌電圖的分析上則是進行平均功率頻率的計算，包含股直肌、股二頭肌、脛前肌與腓腸肌。結果：本研究的結果顯示，連續跳躍攔網會使得股直肌的平均頻率分別下降3.0%與6.1%，而脛前肌的平均頻率分別下降3.5%與6.7%。此外在30毫秒內的發力（爆發力）也有下降的情形(3.5%)。結論：排球運動員在反覆跳躍的疲勞狀況下，垂直跳躍的發力率表現是受到膝伸肌的疲勞所影響，因此無法產生最佳的肌肉強度、最大力量的輸出與協調能力。

Purpose: The purpose of this study was aimed to investigate and analyze the electromyographic (EMG) difference and kinetics of lower extremity for volleyball players during continuous blocking jumps. Methods: Twelve Division I collegiate volleyball players (height: 185.5 ± 3.5 cm, weight: 79.5 ± 5.2 kg, age: 20.5 ± 1.5 years) were recruited in this study. The participants were required to perform 14 blocking jump with 90% maximum jump height for 3 sets. The rest time between sets is three minutes. Ten Vicon T40 motion analysis system, one Kistler force-plant and BTS Free EMG were used to collect the kinematic, kinetic and EMG signal variables. All the data were processed by a self-development program. The peak power output (PPO), maximum rate of force development (mRFD) and relative net impulse (RNI) were calculated by kinetic parameter form each jump. The mean frequency (MF) of rectus femoris muscle (RFM), biceps femoris muscle (BFM), anterior tibialis muscle (ATM) and gastrocnemius muscle (GM) were computed form EMG signal. Results: The results of this study showed that the continuous blocking jump caused the MF of the RFM to decrease by 3.0% and 6.1%, respectively, and the MF of the ATM decreased by 3.5% and 6.7%, respectively. In addition, the mRFD within 30 milliseconds also decreased by 3.5%. Conclusion: Under the fatigue condition of repeated jumping, the volleyball player's performance of vertical jump was affected by the fatigue of the knee extensor muscle, so it can not produce the best muscle strength, maximum power output and coordination ability.