The Study On College Student Sprinters Isokinetic Knee Flexion And Extension Movement Characteristics Of The Muscle Work

ObjectiveSprint, a limit strength exercise, is a typical speedy and powerful project. Sprint power source is the results of the coordinating role of the various human body muscles.The muscles work with specific characteristics, so sprint strength training should be based on the characteristics of muscle to design and work. This study attempts to synchronize EMG and isokinetic testing technology into sprinters knee movement study. Combining sports anatomy, sports training science, sports bio-mechanics and many other subject knowledge we analyze the main muscles' participation and contraction when sprint athletes involved in running, as well as the characteristics of the sprinter muscles of various joints in the body, to reveal different parts of the muscles from the internal relations, which are much more in line with modern technology of the muscles work characteristics so that we provide some ways and means of strength training.MethodologyUsing the German Isomed2000 Isokinetic test system, aligning the subject's knee and power shaft, fixing the trunk and thigh, we test the contraction strength athletes around the knee muscles. Ten minutes before the test, it needs warm-up activities.The conclusion of a group of preparations is to adapt to experimental conditions for qualification with a formal experiment. First conduct a formal and same long test, then leg flexor and extensor were tested respectively and asked participants to use 1-2s to achieve the most vigorous and maintain 5s.After completing a test break 5mins. Then start the movement pattern of isokinetic concentric--heart contraction, the test speed at 60°/s,120°/s,240°/s for each speed. Subjects do its utmost to five times of the knee flexion and extension between the two groups rest 5mins. Then start the movement mode of isokinetic eccentric-eccentric exercise, the test speed at 60°/s,120°/s, repeated five times for each speed between the two groups rest 5mins.Subjects were asked to do both knee flexion and extension efforts, and should be given verbal encouragement. In the isokinetic test, we gather and record synchronously the antagonistic muscles of subjects with knee (quadriceps, tibialis anterior, biceps femoris, gastrocnemius) and the signals of EMG activities of the signal, and use professional cameras and video sync signals for video capture.Results(1)Sprinters leg flexion, extension peak torque ratio around college students is close to the normal range of athletes and develops much balanced. But compared with elite athletes, it has greater range of torque ratio of the gap, and therefore, we need prompt coaches to enhance sprinter leg flexor muscle training; Ordinary college students about leg muscle flexion and extension peak torque ratio are in line with that of healthy adults.(2) When do the isokinetic eccentric-eccentric exercise knee flexor movement, the main muscles involved in the work are the biceps femoris, gastrocnemius middle of tibialis anterior muscle. With the angular velocity increases the value of IEMG changes as follows:biceps femoris>gastrocnemius middle>tibialis anterior muscle. Biceps femoris IEMG of college student sprinters was significantly greater than the normal college students (P<0.01),but also in the process of the knee flexor eccentric exercise, the middle section of gastrocnemius muscle IEMG value with the rate of increase is greater than the radial movement, in line with the sprint athletes in the sport multi-purpose centrifuge gastrocnemius muscle contraction.(3)When do the isokinetic eccentric-eccentric exercise knee extensor movement, the main muscles involved in the work are the quadriceps, whose IEMG increases with the angular velocity dropping. During the process of knee extension, angular velocity increasing the shares of four Head muscle IEMG value is greater than eccentric exercise.Extensor muscle strength is the key element in the sprinters centrifugal specific performance, so coaches should strengthen the centrifugal forces and extensor training of sprinters.(4)When do the isokinetic eccentric-eccentric exercise knee flexor movement, with the angular velocity increasing the rate of the student sprinter antagonist/active muscles (quadriceps/biceps femoris, tibialis anterior/gastrocnemius Middle) declines.Meanwhile, ordinary college students are on the contrary. Athletes antagonist is relax fully, reducing the resistance while ordinary college students with active sync muscle tension, which increases the resistance.(5)When do the isokinetic eccentric-eccentric exercise knee extensor movement, the sprint athletes and regular students antagonist/active muscle (biceps femoris/ quadriceps, gastrocnemius middle/tibialis anterior muscle) ratio have significantly differences (P<0.01).With the angular velocity increasing, the antagonistic muscle and active muscles of ordinary college students were significantly larger than that of the sprinters.This is because the extensor strength of sprinters is significantly higher than ordinary people.During the training university students sprinters should strengthen the quadriceps biceps femoris, but also gastrocnemius muscle training, so that maintain active muscle and antagonistic muscle balance.