Surface Electromgraphy Of Quadriceps Femoris In Knee Injuryed Patients With Jiont Dysfunction

ObjectiveTo explore how jiont dysfunction affects quadriceps muscles function in patients with unilateral knee injuryMethods30 unilateral knee injured patients with jiont dysfuntion were assesed for isometric EMG activity of vastus lateralis(VL),vastus medialis obliques (VMO) and rectus femoris(RF)of both thighs during three 5-s maximal isometric voluntary contractions at a knee joint angle of 15°,30°(0°_ full knee extension) ,and torque were recorded at same time . At full knee extention in sitting position 20% maximal voluntary contraction (MVC), the EMG of the rectus femoris (RF), vastus lateralis (VL) and VM muscle were established in 13 unilateral knee injured patients with jiont dysfunction who knee active range were 60°or more than 60°.ResultsBetween unaffected side and affected side, The AEMG,MPF values of VL,VMO and RF muscles in affected knees are significantly lower during maximal isometric voluntory contraction at knee15°,30°flexion than those in unaffected knees, as well as the torque, Additionally,the VL/VMO ratio of MPF, MF,AEMG are similar in both side during MVIC at knee flexion of 15°and 30°except MPF of knee flexion of 15°. At full knee extention in sitting position 20% maximal voluntary contraction (MVC), MPFs and MFs of VL in unaffected side were greater than affected side, MPFs,MFs of VMO and RF were not different in both side. different heads of quadriceps , In unaffecteed side , at knee 15°,30°flexion, the AEMG,MPF values of VL are greater than VMO and RF, the MF of VL,VMO and RF were not significantly different.In unaffecteed side , at knee 15°,30°flexion, the AEMG,MPF and MF values of RF are greater than VMO and VL(P<0.01 or P<0.05), MF values of RF are greater than VMO and VL(P<0.01 or P<0.05)at knee 15°flexion, MF values of VL and RF were not significantly different but all greater than VMO at knee 30°flexion (P<0.05).Between two knee flexion angle, In unaffecteed side, AEMG,MPF of VL,VMO and RF between knee 15°and 30°flexion were not significantly diffirent,MF of VMO,RF were not significantly different between two knee flexion angle except VL; In affected side ,AEMG,MPF,MF of VL,VMO and RF between knee 15°and 30°flexion were not significantly different, the VL/VMO ratio of MPF, MF,AEMG are similar in both angle.ConclusionsEMG can provide quantitative measurements of muscle function, the isometric strength and neuromuscular acvtive lever are lower in affected limb in knee injured patients with knee dysfunction. RF may be affected less more than VL and VMO , It is suggested that the increases or same in endurance of the involved muscle may have been due, in part to selective Type II fiber atrophy in the involved muscle.Rehabilitation should focous on muscle strength increasment.