Analysis Of The Characteristics Of Muscle Strength And Balance Ability Of Lower Extremity Flexors And Extensors Of Physical Education Students With Knee Injury

Objective:To study anterior cruciate ligament injury(ACL)and patellofemoral joint pain syndrome(PFPS)in common knee injuries,and to analyze the characteristics of knee joint flexor and extensor muscle strength and balance ability of lower limb under the condition of injury.It hope to provide theoretical basis for rehabilitation training on students majoring in sports with knee injuries.Research methods:A total of 39 sports students were recruited in this study,including 15 in the anterior cruciate ligament injury group(ACL group),12 in the patellofemoral pain syndrome group(PFPS group),and 12 in the healthy group.Before the experiment,the Visual Pain Assessment Scale and the Lysholm knee Score Scale were used to evaluate the pain level of the PFPS group and the knee function of the ACL group,respectively.The Physiomed Con-Trex Isokinetic Muscle Strength Test System and SportKatTM Model 4000-TS Balance Ability Test System were used to test the isokinetic muscle strength of the knee joints and balance ability of three groups of physical education majors,respectively.There were no significant difference in age,height,weight among the three groups(P>0.05).All the subjects in each group completed isokinetic muscle strength and balance ability test in random order.Research result:(1)The independent sample T test showed that in the dynamic state of both feet standing with eyes open,the balance ability of healthy group was lower than that of PFPS group and ACL group(P_a<0.05,P_b<0.01);The ratio of FB and RL of the healthy group was lower than that of the PFPS group and ACL group(P_a<0.01,P_b<0.01).(2)Obtained from the explosive strength indicators of knee joint muscle group,TPT of the healthy group was smaller than that of the PFPS group and ACL group(P_a>0.05,P_b>0.05).The AP,TW,and T@0.2of flexors and extensors in the healthy group were all larger than those in the PFPS group and ACL group(P_a<0.01,P_b<0.01).(3)Known from the stability and strength indicators of knee joint muscle group,the DPT value of flexor and extensor muscles in the healthy group was higher than that of the PFPS group.DPT values of flexors and extensors in the healthy group were greater than those in the PFPS group(P_a<0.01);DPT values of extensors in the healthy group were greater than those in the ACL group(P_b<0.01),and flexors were smaller than those in the ACL group(P_b>0.05).The H/Q value of the healthy group was larger than that of the PFPS group and smaller than the ACL group(P_a<0.01,P_b<0.01),and the H/Q values of the three groups of subjects showed an increasing trend with the increase of the angular velocity.(4)From the strength and endurance indicator of knee joint muscle group,the FA mean value of PFPS group and ACL group was higher than that of healthy group(P<0.01).At slow speed(60o/s),the endurance ratio of flexor and extensor of the PFPS group and ACL group was close to 1(P<0.01).At rapid speed(180o/s),the fatigue indicator of the flexor and extensor group in the PFPS group was close to 1(P_a<0.01),the fatigue indicator of the flexor group in the ACL group was less than 1(P_b<0.05),and the extensor fatigue indicator was close to 1(P_b<0.05).The flexor and extensor group endurance of patients with knee joint injuries is poor,and easy to fatigue.(5)In the isokinetic strength test,the three indicatores of PT,PT/BW,and torque at 30°reflect the maximum strength of the muscle at a slow speed(60o/s)and reflect the rapid strength of the muscle at a fast speed(180o/s).The independent sample t-test showed that the PT,PT/BW,and flexor and extensor muscles of the healthy group were higher than those of the PFPS group and the ACL group at slow speed(60o/s)and fast speed(180o/s)(P<0.01).The extensor 30°T indicator of the healthy group was significantly greater than that of the PFPS group and ACL group at both speeds(P<0.01).The indicator of flexion at 30°T of the PFPS group was not significantly difference of that in the healthy group(P_a>0.05).(6)The Knee mobility of healthy group was higher than the PFPS group and ACL group(P_a<0.01,P_b<0.01).Analysis conclusion:(1)In the test of balance ability,patients with PFPS and ACL injuries have a downward trend in the dynamic balance ability,showing the weak ability of lower limbs to maintain balance.(2)In the isokinetic strength test,the healthy group,the PFPS group and ACL group showed certain differences on the curve of extensor torque.The moment curve of healthy people have the characteristic of symmetrical single peak pattern,patients with PFPS showed bimodal image characteristics,patients with ACL injury have a plateau characteristic curve in the middle.(3)In isokinetic strength test,the PFPS patients only showed weaker muscle strength in the aspects of explosive force of extensor muscle,flexor and extensor muscle endurance,fast strength of extensor muscle and activity.(4)In isokinetic strength test,patients with ACL injury only showed weaker muscle strength in the aspects of explosive force of flexor and extensor muscle,muscle endurance and fast strength.