Comparison of Knee Kinematics and Muscle Activity of the Lower Extremities between Single and Double Leg Drop Landing

[目的]本研究の目的は,片脚および両脚着地における膝関節角度と下肢筋活動の相違を検証することである。[対象]健常男性9名とした。[方法]高さ30 cmの台から片脚と両脚による着地動作を行った。関節角度は,矢状面上の膝屈曲角度と前額面上の膝外反角度を算出した。筋活動は,中殿筋,大内転筋,大腿直筋,内側広筋,半膜様筋,大腿二頭筋について記録した。[結果]片脚着地は両脚着地より,有意に膝屈曲角度が小さく,膝外反角度は大きかった。片脚着地の筋活動は,すべての筋で両脚着地より有意に増加した。特に中殿筋は,片脚着地が両脚着地の約3倍を示した。[結語]片脚着地は両脚着地より膝屈曲角度が減少し外反角度が増加するため,前十字靭帯損傷のリスクが高まるものと推察された。[Purpose] The purpose of this study was to determine the effect of two different drop landing tasks on knee kinematics and muscle activities. [Subjects] Nine healthy males participated in this study. [Methods] The subjects performed two different drop landing tasks from a box (height, 30 cm), with the dominant leg and both legs. A motion analysis system was used to obtain knee valgus and maximal flexion angles in the frontal and sagittal planes. An electromyography system was used to record muscle activities of the lower extremities during the drop landing task. [Results] Single leg landing increased the knee valgus angle, decreased the knee flexion angle, and increased the activity of the lower extremity muscles as compared to double leg landing. [Conclusion] Increased knee valgus angle and decreased knee flexion angle with single leg landing may be related to the increased risk of anterior cruciate ligament injury