| Purpose: Research purpose: To explore the surface electromyography characteristics of 400-meter sprinters at different rhythms,and the analysis of the changes of 400-meter sprint performance and related physiological and biochemical indicators in order to enrich and perfect the theoretical system of 400-meter sprint events and formulate reasonable The training program provides a theoretical reference for strengthening the scientific and systematic training.Methods: This article takes 11 400 m sprinters in the School of Physical Education of Jiangxi Normal University as the research object.Using wireless EMG tester and video synchronization,collect the original EMG signals of the athlete's left leg for three consecutive cycles at the nonterminal straight segment(125m)and the terminal straight segment(375m),the signal was studied in two phases: left leg buffer phase and stretch stage.The analysis software that comes with Dalsys EMG tester was used to process the original EMG data,extract the data such as iEMG,MPF,and analyze the 400-meter run at different rhythms.It is used to analyze the muscle strength characteristics and fatigue characteristics of 400 m running under different rhythms,physiological indicators such as blood lactate value,heart rate,and RPE value of athletes are tested,single factor repeated measurement analysis of variance and paired sample T test were performed on the relevant data.Result:1.Self-rhythm performance is the best;pre-fast rhythm is the second;pre-slow rhythm is the worst;under the same rhythm,the change of blood lactate shows a clear upward trend after exercise,and the peak value of blood lactate is higher at 7.5min.The blood lactate value is the lowest under self-rhythm,and the pre-fast rhythm is the highest;2.The pre-fast rhythm RPE is the highest,the pre-slow rhythm RPE is the lowest,and the self-rhythm is centered;the self-rhythm and other rhythms have no significant effect;the pre-fast rhythm and the pre-slow rhythm are significantly different.3.Due to the great exercise intensity of the 400-meter run,the heart rate immediately after exercise reaches 180 beats/minute;there is no significant difference in heart rate immediately after exercise between the rhythms;4.The range of main muscles during the entire cushioning and stretching phase is very stable.The cushioning phase is the gastrocnemius muscle,biceps femoris,anterior tibial muscle,and lateral femoral muscle;the stretching phase is the medial femoral muscle,lateral femoral muscle,and femoral muscle.Biceps and gastrocnemius.5.The rhythm has no significant difference in the MPF of each muscle group between the non-end straight line and the end straight line(P>0.05),and the MPF of each muscle group in the end straight line shows a downward trend.Conclusion:1.Rhythm is the key factor that affects the 400-meter sprint performance: the sports performance under the self-rhythm is relatively stable,and the use of the pre-fast rhythm is of great significance for training and competition.2.The impact of rhythm on blood lactate and heart rate: the body is more adaptable under self-rhythm;the pre-fast rhythm helps improve athletes' lactate tolerance.The monitoring method of heart rate is simple and easy to operate,and the training effect it reflects does not meet the requirements of precision,which can be used as a reference for reference.3.In daily training,we should strengthen the emphasis on strength training of biceps femoris,gastrocnemius,medial and lateral femoral muscles,and at the same time formulate a reasonable training program according to the way the muscles work. |
PDF Full Text Request