RESUMO
BACKGROUND:Patellar tendinopathy is tiny damage at tendon insertion.Changes in the strength balance between medial vastus muscle(VM)and musculus vastus lateralis(VL)in the quadriceps may lead to patellar abnormal motion,even have an impact on the tendon insertion.OBJECTIVE:To compare and analyze knee mechanical charactedstics and surface electromyography of the quaddceps in athletes with patellar tendinopathy.in order to provide scientific basis for the prevention and treatment of patellar tendinopathy.DESIGN,TIME AND SETTING:Self-control experiment was performed in Central Laboratory of Physical Education College of Soochow University from June to July 2009.METHODS:A total of 10 athletes with patellar tendinopathy aged(21.44±1.51)yeam were selected as patellar tendinopathy group and 10 normal athletes aged(21.37±1.36)years were selected as normal control.MAIN OUTCOME MEASURES:①Knee flexor and extensor muscles peak torque in concentric and eccentric isokinetic exercise between two groups.②Comparison of quadnceps integrated electromyogram(IEMG)between two groups.③Comparison of VM/VL in different kinds of exercises between groups.RESULTS:The ratio of flexor and extensor peak torques of the patellar tendinopathy group was significantly greater than the normal group in concentric and eccentric isokinetic exercises(P＜0.05 or 0.01).VM IEMG of the patellar tendinopathy was significantly less than normal group(P＜0.05 or 0.01),but no difference was found in VL and rectus femoris IEMG between two groups.During the period of isometric exercise and isokinetic exercise,the ratios of VM/VL of the patellar tendinopathy group were remarkably lower than the normal group (P＜0.05 or 0.01).CONCLUSION:There are significant differences between flexor and extensor torques in patellar tendinopathy athletes.VM is under-activity and there is an imbalance between VM and VL.