Study On Biological Characteristics Of Rectus Femoris Under Different Contractions

Objective:As the power device of the motor system,muscle can contract and pull bone under the control of the nervous system to produce movement.With the increase of age,human physiological function aging,physiological and morphological structure changes,resulting in muscle function decline,activity ability and quality of life are affected.Among them,rectus femoris is a typical double joint muscle,whose function is to bend the hip and extend the knee.Compared with the other three heads of quadriceps femoris,rectus femoris has more functions and is more likely to cause injury.The purpose of this paper is to study the effects of constant length and constant velocity(60 °/ s、180 °/ s)The changes of rectus femoris morphology,physical parameters and muscle electrical activity before and after strength training;The differences of numerical parameters and fatigue recovery of rectus femoris before and after isometric and isokinetic strength training;To explore the correlation among isomed isokinetic muscle strength tester,electromyography(sEMG),muscle bone ultrasound and myoton;To provide the relevant theoretical basis for the follow-up sports training.Methods:This study mainly uses the experimental method.After the pre experiment,16 healthy male volunteers(8 college students and 8 elderly people)from Nanjing Institute of physical education were selected as the research objects,and the right rectus femoris was selected.The mechanical test and morphological test were carried out.Results:(1)In the isometric and isokinetic exercise,the student group was in the isokinetic(60 °/ s)The maximum torque produced in exercise was the largest,while the maximum torque produced in isometric exercise was the largest in the elderly group.(2)In the isometric and isokinetic exercise,the two groups of people in the isokinetic(60 °/ s)The average power frequency and median frequency are the highest;The student group was isokinetic(60 °/ s)The integral EMG value immediately after exercise was the lowest,and the integral EMG value immediately after isometric exercise was the lowest in the elderly group.(3)Two groups of people isokinetic(60 °/ s)The increase of hardness and the decrease of elasticity are the most obvious after exercise;After isometric exercise,the decrease of hardness value in the elderly group was greater than that in the isokinetic exercise group,and the change of elasticity value in the elderly group was less than that in the student group.(4)The feathering angle and thickness of the two groups immediately after isometric and isokinetic exercise were greater than those before exercise)The numerical change of motion is the most obvious.The recovery of values in the elderly group at 5 and 10 minutes after exercise was lower than that in the student group.(5)After 10 minutes of isometric exercise,hardness was positively correlated with elasticity and thickness.Elasticity is positively correlated with thickness;Before isometric exercise,there was a positive correlation between thickness and hardness.10 minutes after isometric exercise,the maximum torque was positively correlated with the pinnate angle.(6)In the elderly group,isokinetic(180 °/ s)Before exercise,rectus femoris torque and hardness are positively correlated.Immediately after exercise,the torque and elasticity of rectus femoris are positively correlated.There was a positive correlation between thickness and hardness;Constant velocity(180 °/ s)5 minutes after exercise,the maximum torque of rectus femoris was positively correlated with elasticity.Conclusion:(1)The thickness and pinnate angle of rectus femoris increased after isometric and isokinetic exercise.(2)In isometric and isokinetic exercise,the subjects did isokinetic(60 °/ s)The maximum torque value is the largest,and it is easy to feel fatigue during exercise.The maximum torque is related to hardness,elasticity and thickness.The muscle elasticity of the elderly is lower than that of the students.(3)Slow isokinetic training is recommended to improve the strength of rectus femoris,while isometric training is recommended for the elderly.