부산대학교 도서관

We evaluated the isokinetic strength of quadriceps and anterior tibial displacement of the patients with the anterior cruciate ligament (ACL) injury (N=20), and recorded simultaneously electromyography (EMG) of rectus femoris and vastus medialis using surface electrodes. We determined premotor reaction time (PMT), electromechanical delay (EMD), which was considered to represent muscle response, and mean power frequency (MPF) from EMG.The isokinetic strength decreased significantly (p<0.0001) and the anterior tibial displacement increased significantly (p=0.0001) in the lower extremity with the injured ACL.EMD increased significantly (p=0.0216) and MPF of vastus medialis decreased significantly (p=0.0011) in the lower extremity with the injured ACL.These suggested a decrease in quadriceps muscle strength and a delay in muscle response in patients with ACL injury.This was considered to result from the Quadriceps-Avoidance-Gait, characterized by the injured ACL patient, and from the fact that vastus medialis is single-joint muscle.