目的：本研究是透過量測並探討大專男子不同層級排球選手在防守敏捷能力上的差異。方法：本研究以大專特優組12名與公開組12名為研究對象，以自製系統測量後排防守時的整體反應時間（total response time, TRT）、反應時間（reaction time, RT）與動作時間（movement time, MT）之測量。統計方法採用共變數分析（analysis of covariance, ANCOVA）與皮爾森相關係數（pearsoncorrelation coefficient）。結果：特優組在整體反應時間（total response time,TRT）、反應時間（reaction time, RT）與動作時間（movement time, MT）上皆顯著的優於公開組（p ＜ .05）。特優組在TRT與MT間達顯著的相關，而公開組在TRT、RT與MT間皆有顯著相關。結論：特優組選手在後排防守的敏捷能力上優於公開組選手，可能是由於平時訓練之強度與內容的不同。建議公開組選手可在日常訓練中增加敏捷能力訓練以改善防守敏捷能力。

Purpose: This study aimed to measure and investigates the variations of defending agility of male volleyball players between the different levels of University Volleyball League. Method: Twelve elite and twelve sub-elite volleyball players were recruited in this research. Total response time (TRT), reaction time (RT), and movement time (MT) of defending agility in back court were measured by a self-designed system. Analysis of covariance and Pearson correlation coefficient were applied to obtain the variables. Results: Elite players were significant better than sub-elite players in TRT, RT, and MT (p ＜ .05). There were significantly correlations between TRT and MT in elite players and among TRT, RT, and MT in sub-elite players. Conclusion: Elite players were superior to sub-elite players in agility because of training intensity and contents. We recommended that sub-elite players should participate in agility training drill in general training program to improve defending agility.