緒論：運動員具備好的敏捷有助於整體競技表現，但敏捷受到直線衝刺能力及下肢爆發力的影響。雖然研究 證實阻力訓練可有效增強下肢肌力與爆發力，但以牽張-縮短循環（stretch-shortemng cycle, SSC)的原理，強 化肌肉快速離心後瞬間向心收縮能力的增強式阻力訓練，能否強化青少年運動員之敏捷能力尚未經研究充分 證實。本研究的目的是探討五週增強式阻力訓練是否增強青少年運動員的敏捷能力。方法：以高中體育班運 動員為受試者，隨機分為增強式訓練組（plyometric training group, PTG)及控制組（control group, CG)»PTG進 行五週增強式阻力訓練，每週2次，每次40分鐘，CG不接受增強式阻力訓練。二組均於訓練前、後進行各 項能力檢測。所得資料以混合設計二因子變異數分析比較組間各依變項的差異情形。當交互作用達顯著時， 則分別進行獨立樣本單純主要效果檢定及相依樣本單純主要效果檢定。顯著水準定為a=05。結果:PTG的反 向跳與T折返跑獲得顯著增強效果（p< .05)。此外，PTG的反向跳與T折返跑進步百分比亦顯著高於CG (P< .05)。結論：增強式阻力訓練介人青少年跆拳道運動員的訓練計畫中，可提高下肢爆發力的表現並增強代 表改變方向能力的T折返跑速度。

Introduction: Agility is an important aspect of almost every sport. It is influenced by several factors such as straight sprint, leg muscle qualities. One way to improve these attributes is plyometric resistance training. The aim of this study was to determine the effects of a 5 week plyometric resistance training program on the agility performance of adolescent athletes. Methods: 17 male young athletes were randomly divided into a plyometric training group (PTG, n =9) or a control group (CG, n = 8). PTG completed a 5 week plyometric resistance training program that included 2 training sessions per week. Before and after the training period, countermovement jump, 15 meters sprint, T agility test and 505 agility test were evaluated. Data were analyzed by using mixed design of two-way ANOVA to compare the difference within groups, and the difference of training effects between groups. Results: Following the 5 weeks of training, PTG had significant improvements in countermovement jump (p < .01) and T agility test (p < .05). Besides, PTG had significant higher percentage of progress in countermovement jump and T agility test (p < .05) than CO. Conclusions: Plyometric resistance training could enhance countermovement jump and T agility performance. Hence, plyometric resistance training is a great training method for improving agility in adolescent athletes.