疲勞對耐力跑的下肢生物力學與著地型態之影響

Influence of Fatigue on Lower Extremity Biomechanics and Strike Pattern during Endurance Running

目的：探究耐力跑運動中，跑者在疲勞前、後下肢的撞擊力量、著地型態，及下肢運動學特性等運動生物力學現象是否有所差異。方法：以大專體育系有慢跑習慣之男性學生10名為受試對象。兩塊測力板與八台光學攝影機同步擷取受試者於實驗跑道上跑步的資料。每位受試者先進行跑步的前測資料收集，隨後便於跑步機上執行疲勞操弄，接著進行跑步的後測資料收集。以The Motion Monitor動作分析軟體獲得跑步的下肢運動學參數，以及測力板參數，並進一步計算著地型態指數。以相依樣本T檢定，比較各參數在前測與後測間是否有顯著差異，統計顯著水準訂為α = .05。結果：疲勞前、後跑步的速度、步幅、步頻、觸地時間分配，與地面反作用力皆沒有顯著差異。疲勞後觸地瞬間的膝關節屈曲角度會增大，且增大著地期間的膝關節最大外翻角度，此外，觸地瞬間的著地型態指數變小。結論：疲勞後，受試者會增大觸地瞬間的膝關節屈曲，此補償機制或許使得著地的撞擊力不會增大，但著地期間膝關節最大外翻角度在疲勞後會增大，此應與跑步傷害的發生風險有所關聯，此外，疲勞後足掌觸地的位置會移向足跟處，故著地型態指數或許可作為判斷疲勞的依據。

 

Purpose: The purpose of this study was to examine the changes in the impact force, strike pattern, and joint angles of running following fatiguing exercise. Methods: 10 male college students from the physical education department running on a 10-m long straight runway prior to and following fatigue. Two force plates and eight optical cameras were synchronized to the collected data. Ground reaction forces and lower extremity kinematic data were collected from The Motion Monitor software. The custom Excel and Matlab program was used to calculate the data process of strike index. Variables were analyzed using a repeated measures t-test to examine the significant differences between the pre- and post-fatigue during the running stance phase. The statistical significance level was α = .05. Results: No significant statistical differences were found for the running velocity, contact time, strike length, strike frequency, and ground reaction forces before and after the fatiguing exercise. The post-fatigue knee flexion angles at the foot-ground contact increased and, accordingly, the peak knee abduction angles also increased during landing. In addition, the foot strike pattern indices at foot-ground contact decreased. Conclusion: After the fatiguing exercise, participants increased the knee flexion angles at the foot-ground contact to compensate for the ground reaction force. The peak knee abduction angles post-fatigue increased during landing, which may be related to the risk of injury associated with running. Finally, the contact area on the foot shifted towards the rear foot post-fatigue; hence, landing pattern may possibly be used as an indicator for fatigue.