健康族群在不同弓箭步的下肢肌肉共同收縮特徵

Abstract

弓箭步動作被廣泛的運用於增強股四頭肌與腿後肌的力量，並有助於促進肌肉共同活化，共同活化可以增強肌肉在執行動作時的功能，且可以用來評估關節的穩定性，因此，了解股四頭肌和腿後肌的活化狀態，能有益於預防膝關節損傷和運動的穩定。本研究目的為比較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。實驗招募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 (200Hz)、Kistler測力板2塊 (1000Hz)、5個Delsys肌電電極 (1000Hz)。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，收集肌肉活化、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)。統計方法以SPSS20.0版利用單因子重複量數變異數分析 (One way ANOVA with repeated measures) 來比較不同方向弓箭步對肌肉活化的影響。顯著水準設為α = .05。研究結果顯示無論下蹲期或上升期股四頭肌在側弓箭步的活化最大，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期腿後肌在後弓箭步的活化最大，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，而側弓箭不得比值最大。由上述結果結論股四頭肌在側弓箭步的活化最高，在膝關節的伸肌力矩也較高，進而造成側弓箭步在股四頭肌與腿後肌的比值也是三者間最高。而腿後肌在後弓箭步的活化最高，在膝關節伸膝力矩顯著的小於側弓箭步，而在股四頭肌與腿後肌的共同活化比值較接近1。側弓箭步較為股四頭肌主導的動作，會增加膝關節不穩定的機率，因而增加受傷的風險，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，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。Lunge exercises were widely been used to strengthen the quadriceps and hamstrings muscles, and co-activation of the quadriceps and hamstrings could affect stabilization of the knee and movement. Therefore, identifying lunges that facilitate balanced activation of the quadriceps and hamstrings might be beneficial in knee joint injury prevention and stabilization of movement. Purpose: 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. One-way ANOVA with repeated measures was used to exam the differences in biomechanical parameters of the lower limb muscle activations during multiple planes of lunges. Results: The muscle co-activation ratios (Q:H) are calculated as mean quadriceps activation divided by mean hamstring activations during movement. 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. Discussion: 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.