Study On Isokinetic Strength And Grip Strength Validity Of Middle School Boys

Objectives:The strength is the basic fitness and important aspect of physical monitoring and evaluation.Grip strength mainly reflects the static force of forearm flexor group,is common indicator of monitoring strength.But many countries will not use grip strength to monitoring strength because it is subject to occupation and right-hand preference,the objectivity may no more than back strength and leg muscle strength.In this study,via experiment,is intended to compare the validity of grip strength,back strength and leg muscle strength to reflect the whole body strength.finally,identify better monitoring indicator of the strength,carry out a comparative analysison the results of isokinetic test,such as absolut peak torque,flexion and.extension muscle ratio and strength deficit percentage,in order to know the development of muscle strength and make advices on middle school students muscle strength trainingMethods:Used B IODEX SYSTEM 3 isokinetic testing system to collect absolute peak torques of six joints'flexion and extension.Then extracted the public factors with factor analysis and calculated the total fact or score according to public factor contribution rate.Moreover,used simple testing methods to test grip strength,back strength and leg muscle strength of subjects.Calculated separately correlation coefficients between the total factor scores and grip strengths,back strengths,leg muscle strengths via Pearson Correlation Analysis,compared the validity;Results:1.The relevance is maximum between the total factors and back strengths(12-13year,r＝0.794;14-15year,r＝7.98;16-17 year,r＝0.826),followed by leg muscles trength(12-13year,r＝0.768; 14-15 year,r＝0.785;16-17year,r＝0.765),the lowest grip strength (12-13year,r＝0.756;14-15year,r＝0.696;16-17year,r＝0.635);2.Advantage side and non-edge-side muscle strength exist significant differences(P＜0.05),result in strength deficit of knee joint and hip joint. more than normal level(10%);3.Age has effect on muscle strength performance,12-13 year＜14-15 year＜16-17year;4.Knee flexion and extension muscle strength is imbalances.Confrontation muscle ratio lower than normal.Conclusions:1.Grip strength as a monitoring and evaluation indicator of strength,its effectiveness would be better to not as good as back strength and leg muscle strength.The validity of back strength is maximum among them.So,I recommended that use back strength as a indicator to monitor school boys strength and ban the grip strength;2.Advantag side and non-edge-side muscle strength exist significant differences(P＜0.05),so strengthening non-edge-side muscle of knee and hip is significative for prevention of sport injuris;3 Strengthen the knee flexor strength in order to enhance joint stability for the prevention of sports injuries among secondary school students have great significance.