國小高年級學童高台著地下肢負荷與勁度特性之性別差異探討

Gender differences in lower extremity loading and stiffness during drop landing in elementary school students

目的：探討不同性別之國小高年級學童於高台落下時，其著地動作與負荷上的差異及其下肢勁度調節之特性。方法：以國小高年級11名男學童與10名女學童為研究對象，利用一部MegaSpeed高速攝影機（120Hz）與一塊AMTI測力板（1200Hz）同步擷取學童從40公分高台落下的著地資料，透過Kwon3D與KwonGRF軟體進行資料處理，並以彈簧質量模型計算腿部垂直勁度。利用SPSS統計軟體進行獨立樣本t檢定，顯著水準訂為α＝.05。結果：男學童在著地瞬間膝關節角度與緩衝期間膝關節最小角度皆顯著大於女學童。男學童著地期間最大垂直地面反作用力、50毫秒被動衝量、第一、第二峰值負荷率與緩衝期垂直勁度皆明顯高於女學童，且地面反作用力峰值出現時間較女學童提早。結論：國小高年級男學童高台著地動作膝關節採較僵直的著地模式與較大的垂直勁度，使其有較高的下肢傷害風險。Purpose: The purpose of this study was to examine whether gender differences exist in lower extremity landing movement and vertical stiffness during the drop landing task. Methods: Eleven male and ten female elementary school students with no history of lower extremity injury performed a 40-cm drop landing. One MegaSpeed camera (120 Hz) synchronized with an AMTI force plate (1200 Hz) were used to collect the kinematics and kinetics data. Leg vertical stiffness was calculated by using a spring-mass model. An independent t-test was used for statistical analyses (p < .05). Results: Male students landed with greater knee angle at initial foot contact than female students. In addition, male students exhibited greater maximum ground reaction force, passive impulse, loading rates and vertical stiffness, and time to peak force was earlier than female students. Conclusion: Male elementary school students may have a higher risk of injury in lower extremity during drop landing due to their straight knee position and higher leg vertical stiffness.