무릎 신전근 피로 수준이 외발 드롭 착지 시 무릎 관절 안정성에 미치는 영향

Abstract

This study was to investigate the effect of experimentally induced knee extensor muscle fatigue on biomechanical variables related to knee stability during landing after a drop jump. Methods: A total of 14 young men participated voluntarily. As for the fatigue induction method, isokinetic equipment (Biodex System 4, Biodex Medical Systems, Inc. USA) was used, Kinematic data of the lower limbs were collected using a 3D Motion Analysis Eagle system (EVART 4.6, Santa Rosa, CA, USA) connected to 12 cameras at a sampling rate of 200 Hz, and ground reaction forces were obtained using an AMTI OR6-5 force platform (Watertown, MA, USA) was used to collect at a sampling rate of 1200 Hz. Results: The maximum knee flexion angle during one-leg drop landing was significantly increased after fatigue induction than before fatigue induction, but there was no significant difference among the fatigue induction conditions in knee valgus and varus, lateral rotation and medial rotation during one-leg drop landing. The shear stress in the tibia showed a tendency to increase according to the level of fatigue, but no significant difference was found. On the other hand, in the sagittal plane, the maximum knee joint moment was significantly decreased after fatigue induction, and the maximum ground reaction force was also found to be significantly decreased in the condition after fatigue induction compared to the condition before fatigue induction. Conclusion: Fatigue of the knee joint extensors following the fatigue protocol did not lead to significant changes in biomechanical variables related to knee stability. However, there was a significant decrease in maximum knee joint moment and maximum ground reaction force, and a significant increase in maximum knee joint angle during one-leg drop landing after fatigue induction. Therefore, the results of the study demonstrated that local fatigue (knee extensor fatigue exercise) according to the fatigue protocol did not affect biomechanical variables related to knee stability, but did affect biomechanical variables related to task performance.