| Research Objectives:Football requires higher joint strength of the lower limb,and good lower limb strength is one of its essential elements.As the main dominating joint in football,knee and ankle ligament injuries had a profound impact on football specialty college students.The flexor strength,extensor strength and their ratios of the knee and ankle are critical to their stability and balance.It is an important factor affecting knee and ankle ligament injuries,and it is easy to monitor.Therefore,how do students with knee and ankle ligament injuries to schedule lower limb muscle recovery training to deal with injuries,and how to effectively prevent and avoid knee and ankle ligament injuries from the perspective of muscle strength for uninjured students is a urgently issues need to solve for football specialty college students and coach and sports researchers.This study used questionnaires to obtain the cognition of knee and ankle ligament injuries and lower limb strength training in football specialty college students;obtain muscle strength data by isokinetic muscle strength test,and then compare and find the weak muscle strength of injured lower limb;according to the follow-up survey results and muscle test data to investigate the relationship between knee and ankle ligament injuries and strength,and pass the Receiver Operating Characteristic Curve(ROC)curve to find the best critical value of the muscle strength index of uninjured students for early warning.It is proposed to find a relatively effective plan for the special training of muscle for football specialty college students and coaches,and it provides theoretical basis and experimental reference for football specialty college students to deal with knee and ankle ligament injuries and reduce the risk of injuries.Research Methods:1.Using questionnaire survey to investigate the cognition of knee and ankle ligament injuries,injuries conditions,and lower limb strength training in 176 football specialty college students.2.Using the Isomed 2000 isokinetic muscle test system to test the strength of the knee and ankle joints of 46 football specialty college students in Shaanxi Normal University,obtain the flexor and extensor centripetal Torque Max(TM,refers to maximum muscle strength)and Hcon/Qcon value(H/Q value,refers to centripetal peak torque ratio)of the injured(weak side)and the ipsilateral joint of uninjured students at test speeds of 60°/s(seconds),90°/s(seconds)and 120°/s(seconds)to find weak muscles strength of injured students through comparison.3.Using the follow-up survey method to investigate the non-injury football specialty college students for 4 months,combine the muscle strength data to explore the relationship between knee and ankle flexor and extensor strength and ligament injuries,and through ROC curve analysis to find the best critical value of muscle strength for early warning.Research Results:1.Survey results:(1)95.71%of football specialty college students don't know their lower limb flexor and extensor strength.Most football specialty college students don't know much about the knee and ankle joint ligaments and muscles,the flexor strength and extensor strength,and the relationship between ligament damage and flexor and extensor strength.It shows that football specialty college students need to deepen their understanding of the muscle strength of their lower limb and strengthen their knowledge of the anatomy of the knee and ankle joints.(2)More than half of football specialty college students don't pay attention to lower limb strength training,and there is no lower limb strength training schedule in a week,and 54.71%of football specialty college students don't pay attention to the balanced development of flexor and extensor strength during lower limb strength training.It shows that football specialty college students lack balanced and reasonable lower limb strength training.(3)The proportion of students with ligaments injured of the knee accounted for 11.43%,with mild and moderate injuries mainly;the proportion of students with ligaments injured of the ankle accounted for 67.57%,with mild and moderate injuries mainly,and most of the injuries were lateral ligaments inj ury;the most of students believe that knee and ankle ligament injuries will adversely affect their participation in football,but only a small number of injured students often arrange targeted recovery training after the injured,and more than half of the injured will play football in an unhealed situation.It shows that knee and ankle ligament injuries can cause adverse effects on football specialty college students,but the injured students lack sufficient attention and targeted recovery training.(4)Only 41.43%of the students realize that insufficient or imbalance muscle strength is a risk factor that can cause knee and ankle ligament injuries.It shows that most of the football specialty college students didn't realize that muscle strength can also cause knee and ankle ligament injuries.2.The results of comparison of muscle strength data of students with and without ligament damage:(1)Knee ligament injured football specialty college students injured knee's flexor centripetal Peak Torque,extensor centripetal Peak Torque and H/Q values lower than ipsilateral knee of uninjured student at 60°/s,90°/s and 120°/s,show significant differences(P<0.05).It is shown that the strength of the knee flexor and extensor and the balance of flexor and extensor strength of football specialty college students with knee ligament injuries are significantly worse than those of the uninjured students on the ipsilateral knee.(2)Ankle joint ligament injuries football specialty college students injured ankle's flexor centripetal Peak Torque and H/Q values lower than ipsilateral ankle of uninjured students at 60°/s,90°/s and 120?°/s,show significant differences(P<0.05).It is shown that the strength of the ankle flexor and the balance of flexor and extensor strength of football specialty college students with knee ligament injuries are significantly worse than those of the uninjured students on the ipsilateral knee.3.The results of correlation analysis of ankle joint flexor and extensor strength and ligament injuries:Uninjured football specialty college students with weak ankle ligament injuries and its 60°/s flexor centripetal Peak Torque,120°/s flexor centripetal Peak Torque,60°/s extensor centripetal Peak Torque,90°/s extensor centripetal Peak Torque shows a medium negative correlation,and the correlation was significant(P<0.05).It shows that there is a certain correlation between the strength of ankle joint flexor and extensor muscle and ligament injuries.4.The results of ankle ROC curve analysis of muscle strength and ligament injuries:(1)The optimal critical value of the 60°'/s flexor Peak Torque of the weak ankle joint of the uninjured football college students is 34.5N·m.When the student's 60°/s flexor centripetal Peak Torque? ?34.5 N·m,the injury rate is 15.3%,when the 60°/s flexor centripetal Peak Torque<34.5N·m,the injury rate is 54.5%,Area Under Curve(AUC)=0.805;the optimal critical value of the 120°/s flexor Peak Torque of the weak ankle joint of the uninjured football college students is 24.5N·m.When the student's 120°/s flexor centripetal Peak Torque ?24.5 N·m,the injury rate is 9.1%,when the 120°/s flexor centripetal Peak Torque<24.5N·m,the injury rate is 53.8%,AUC= 0.773;the optimal critical value of the 600/s extensor Peak Torque of the weak ankle joint of the uninjured football college students is 97.5N·m,When the student's 600/s extensor centripetal Peak Torque?97.5 N·m,the injury rate is 14.2%,when the 60°/s extensor centripetal Peak Torque<97.5N·m,the injury rate is 60%,AUC=0.785;the optimal critical value of the 90°/s extensor Peak torque of the weak ankle joint of the uninjured football college students is 79N.m,When the student's 60°/s extensor centripetal Peak Torque?79 N.m,the injury rate is 12.5%,when the 60°/s extensor centripetal Peak Torque<79N·m,the injury rate is 75%,AUC=0.824.It shows that when the ankle joint flexor and extensor Peak Torques of football college students are below the critical value,the ligament injury rate is higher and they may suffer more risks of ligament injuries,flexor Peak Torques and extensor Peak Torques can be used as early warning indicators of ankle ligament injuries in football college students.Research Conclusions:1.Football specialty college students have a weak knowledge of knee and ankle ligaments and anatomy of the physiology of muscles,they do not fully understand the relationship between joint flexor and extensor strength and injuries,they insufficient understanding of their joint flexor and extensor muscle strength and lack special ligament prevention damaged consciousness;some football specialty college students with knee and ankle ligament injuries lack targeted recovery training,and there is a phenomenon of participating in football without recovery.2.The flexor strength,extensor strength,and H/Q value of the injured knee joint ligament in football specialty college students were significantly lower than those of the ipsilateral knee of the uninjured students,which may be the reason why the knee ligament was easily damaged again.3.The flexor strength and H/Q value of the injured ankle ligament in football specialty college students are significantly lower than the ipsilateral ankle of the uninjured students,which may be the reason why the ankle ligament is easily damaged again.4.The decline of the weak side ankle joint flexor and extensor muscle strength in football specialty college students without ankle ligament injury may increase their ligament injury risk,The 60°/s and 120°/s ankle joint flexor centripetal Peak Torque and the 600/s and 90°/s extensor centripetal Peak Torque can be used as early warning indicators of ankle joint ligament damage.The optimal critical values are 44.5 N·m,26.5 N·m,98 N·m,80.5 N.m,below the threshold,it is vulnerable to more ligament damage. |
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