緒論：弓箭步動作被廣泛地運用於增強股四頭肌與腿後肌的力量，常應用於傷後復健與運動訓練，並有助於促進肌肉共同活化。肌群之間的共同活化可以增強肌肉在執行動作時的功能，肌肉活化及關節力矩可以用來評估關節穩定性的好壞。常見的弓箭步有前、側、後弓箭步，可以訓練下肢單側肌群，調整左右兩側的差異，因此，想要了解弓箭步動作是否會因為不同方向而產生不一樣的生物力學狀態。本研究比較前、側、後三種弓箭步肌肉活化狀態、共同收縮模式及關節力矩，從中找出三種動作的生物力學特徵。方法：招募 12名健康大專男性 (年齡 20.7 ± 1.4歲，身高 174.6 ± 3.9公分，體重 68.8 ± 8.5公斤)、10台 Vicon紅外線攝影機 (200 Hz)、Kistler測力板 2塊 (1000 Hz)、5個 Delsys肌電電極 (1000 Hz)。肌電電極黏貼於慣用腳的股直肌、股內側、股外側、股二頭與半腱肌，收集不同弓箭步動作中的肌肉活化情形，分析動作中的肌電訊號、關節力矩並計算肌肉共同活化比，為平均股四頭肌活化除以平均腿後肌活化。結果：無論下蹲期或上升期側弓箭步的股四頭肌活化皆為三種弓箭步中最大，且三種弓箭步在上升期的股四頭肌活化皆大於下蹲期；而無論下蹲期或上升後弓箭步的腿後肌活化為三種弓箭步中最大，且三種弓箭步在上升期的腿後肌活化皆大於下蹲期；側弓箭步的膝關節伸肌力矩為三種弓箭步中最大，比較共同活化發現後弓箭步的比值最趨近於 1，而側弓箭步的比值最大。討論：側弓箭步較為股四頭肌主導的動作，可能會增加膝關節不穩定的機率，而增加受傷的風險，而後弓箭步因為股四頭肌與腿後肌活化比率較平衡，能提高膝關節穩定性。三種弓箭步都能促進肌肉的共同活化，只是會因為不同方向產生不一樣的肌肉活化比，因此在選擇動作的過程中，可以循序漸進的選擇膝關節穩定性最高的後弓箭步，先強化膝關節的穩定，再做前弓箭步的訓練，最後再進階到較具有挑戰性的側弓箭步，避免膝關節一開始就有過大的負荷。

Introduction: Lunge exercises commonly used in injury rehabilitation and physical training to strengthen quadriceps and hamstrings . Common lunge exercises are forward, side and reverse lunge. Lunge exercises were known to facilitate the muscle co-activation during motion. The co-activation of the quadriceps and hamstrings could affect movement strategy and provide stabilization of the knee joint, joint moment could be used to assess the joint stability. Lunges could train the unilateral lower limb muscle group, adjust the posture or muscle strength compensation, thus, to identify lunges that facilitate balanced activation of the quadriceps and hamstrings might be beneficial in knee joint injury prevention and stabilization of movement. Therefore the purpose of this study was to examine the co-activation of the quadriceps and hamstrings during multiple planes of lunges. Methods: There were twelve healthy collegiate individuals volunteered to participate in this study (age 20.7 ± 1.4 yrs, height 174.6 ± 3.9 cm, weight 68.8 ± 8.5 kg). Surface EMG signals were collected by five Delsys Trigno sensors at 1000 Hz. Sensors were placed on rectus femoris, vastus lateralis, vastus medialis, biceps femoris, semitendinosus of the dominant leg. The muscle co-activation ratios (Q:H) were calculated as mean quadriceps activation divided by mean hamstring activations during movements. Results: The quadriceps activation and knee extensor moment of side lunge was greater than other two lunge exercises, the hamstrings activation of reverse lunge during descending phase and ascending was greater than other two lunge, The Q:H ratios of reverse lunge was smaller than other two lunge exercises. Conclusion: A resulting Q:H ratio equal or close to 1.0 indicates a more balanced muscle activation. The smaller Q:H ratio (close to 1.0) during descending phase of reverse lunge could be peculated that reverse lunge was a more hamstring dominant exercise than other two lunge exercises. A significant greater Q:H ratio of side lunges could indicate that a stronger quadriceps muscle activation was existed and tended to lead to greater stresses on the knee joints during descending phase.