髖外展內收比對單腳落地下肢生物力學之影響

Abstract

前言：作用與拮抗肌群肌力失衡為被視為易引發傷害之風險因子，髖部內外側動作肌群具穩定骨盆之角色，其功能性缺損將導致運動表現下降，甚至連帶落地時遠端關節受損，而兩肌群在產生力量能力及動態運動期間的神經肌肉招募比率，其何者對單腳落地期間動作模式能產生影響，仍缺乏明確結論。目的：以髖外展與內收肌群肌力不對稱及動態運動中肌群的招募模式作為預測指標，探討其對單腳落地動作模式之影響程度，以確認何者變項具備潛力作為未來傷害預防之參考依據。方法：招募20名男性大專公開一級運動員。使用等速測力儀測量髖外展與內收肌群之最大等速肌力，後以三維動作捕捉系統同步高速紅外線攝影機 (Vicon Motion Systems, 200 Hz )、測力板 (Kistler, 2000 Hz) 及表面肌電 (Delsys EMG, 2000 Hz)，收集單腳前向及側向落地之運動學與動力學參數，並針對落地階段分期進行資料分析。統計分析先以皮爾森積差相關確認指標與參數之相關性，後導入逐步迴歸分析以評估預測變項對結果變項之影響程度。結果：主要發現外展相對內收肌力較弱時，會增加膝關節額狀面力矩 (R2=.22; p<.05)；落地階段中EMG招募比率越相近時，能減少膝關節額狀面的關節活動 (R2=.21; p<.05)，及避免髖內收動作的產生 (R2=.27; p<.05)；亦發現EMG招募比率愈相近能增加矢狀面髖、膝關節屈曲角度。結論：髖外展與內收肌群肌力及神經招募的比率對單腳落地動作的影響有所不同，當兩肌群肌力平衡與實現共同收縮時，能實踐較佳的落地策略以減緩傷害風險。以作用與拮抗肌群間的功能性差異檢視肌力不足，有助於避免個體差異所導致缺乏肌力不夠客觀之情形，提供臨床實務上作為健全運動員預防傷害之參考指標。未來可考慮擴大分析其他肌群，或是探討傷害族群是否有明顯髖外展與內收肌力失衡之情形。Introduction: Muscle strength imbalances between agonist and antagonist groups have been recognized as risk factors for sports injuries. The hip abductors and adductors play a crucial role in stabilizing the pelvis, and functional deficits in these muscle groups may lead to decreased athletic performance and an increased risk of distal joint injuries during landing. However, it remains unclear whether strength capacity or neuromuscular recruitment ratios during dynamic movements are more influential in shaping single-leg landing mechanics. This study investigated hip abductor-adductor strength asymmetry and neuromuscular recruitment patterns during dynamic movements as predictive indicators and determined their influence on single-leg landing mechanics. The goal is to identify potential variables that could serve as references for injury prevention in the future. Methods: Twenty male collegiate Division I athletes were recruited. An isokinetic dynamometer was used to measure the peak isokinetic strength of the hip abductor and adductor muscles. Kinematic and kinetic parameters during single-leg forward and lateral landings were recorded using a 3D motion capture system with cameras (Vicon Motion Systems, 200 Hz), a force plate (Kistler, 2000 Hz), and surface electromyography (Delsys EMG, 2000 Hz). The landing phase was segmented for detailed analysis. Pearson's correlation was first used to examine the relationships between indicators and biomechanical parameters, followed by stepwise regression analysis to assess the predictive power of each variable. Results: The main findings revealed that relatively weaker abductor strength compared to adductor strength was associated with increased frontal plane knee moments (R² =.22; p<.05), particularly during side-step landing tasks. Additionally, when the EMG activation ratio between the two muscle groups was more balanced during the landing phase, there was a reduction in frontal plane knee motion (R2=.21; p<.05) and a decreased tendency for hip adduction (R2=.27; p<.05). Moreover, a more balanced EMG activation ratio was also associated with increased hip and knee flexion angles in the sagittal plane. Conclusion: Hip abductor and adductor strength and their neuromuscular recruitment ratios affect single-leg landing mechanics differently. When the two muscle groups are balanced in strength and co-contraction is achieved, better landing strategies may be exhibited, consequently reducing the risk ofinjury. Assessing functional discrepancies between agonist and antagonist muscles may help identify strength deficits more objectively, minimizing the impact of individual variation. This approach may be a useful reference for clinicians in injury prevention for healthy athletes. Future studies may consider including more muscle groups or investigating whether athletes with prior injuries demonstrate greater abductor-adductor strength imbalances.