Effects Of Different Hardness Of Basketball Sole And Falling Height On Biomechanical Characteristics Of Lower Limbs

Basketball is a multi person antagonistic sport combined with a variety of sports forms.Jumping is always accompanied by the basketball movement.The impact of the ground on the joints of the lower limbs is inevitable after jumping to the ground.In the landing stage,the kinematic and dynamic indexes of the lower limb joints and the muscle activities of the lower limbs are changing,which will also affect the muscle activities of the lower limbs.The abnormal movement of lower limbs can lead to joint injury,and the hardness of basketball sole affects the change degree of lower limb joint.This study aims to analyze and study the influence of basketball shoes with different hardness soles under different falling height and active falling action on the biomechanical characteristics of lower limbs,and to explore the variation rules of lower limb joint kinematics,dynamics and lower limb surface electromyography index when the human body completes active falling action landing at different falling heights,so as to provide future sports training,basketball sole design and preventive operation Suggestions and suggestions on dynamic injury were provided.The research methods were as followsIn this study,vicon optical motion capture system,Kistler force measuring platform and noraxon surface electromyography analysis system were used to test 10 junior basketball majors in Wuhan Institute of physical education.The subjects wore basketball shoes with different soles hardness to complete the active falling action at different heights,and to explore the changes of biomechanical indexes of lower limbs at the time of landing to the end of buffering The situation.The research conclusion is as follows1.Sole hardness and falling height have an impact on the biomechanical characteristics of human lower limb sports.By comparing the effects of different sole hardness on the biomechanical characteristics of lower limb sports,it is found that the influence of different sole hardness on the biomechanical indexes of lower limb sports does not show linear changes,so it is impossible to rank and compare the advantages and disadvantages.2.The results show that the comprehensive level of the sole of basketball shoes with 50 hardness is the best.When the falling height is certain and the sole hardness is different,the sole can reduce the ankle joint back extension and knee extension,hip joint flexion angle,back extension and flexion angular velocity;in terms of dynamic index,the sole can buffer the grfmax brought by the ground,and reduce the joint back extension of ankle joint to knee joint and hip joint However,the change of sole hardness has no significant effect on the plantar pressure center.3.When the hardness of sole is constant,the angle of ankle joint back extension,knee joint and hip joint flexion are increased with the increase of falling height;the angular velocity of ankle joint back extension,knee joint and hip joint flexion angle is increased;in terms of dynamic index,with the increase of shoe sole hardness,the ankle joint back extension,knee joint and hip joint flexion angle velocity are increased The increase of the falling height increases the grfmax received by the human body,which increases the impact force on the human body and increases the risk of impact injury;it increases the offset distance of the plantar pressure center in the X and Y axes,and reduces the stability of the human body when landing;the higher the falling height is,the less conducive to the maintenance of the stability of the human body;it also increases the peak torque of ankle joint extension and knee and hip joint flexion ? However,the increase of falling height has no regular effect on joint angle,angular velocity and joint torque in x-axis direction.4.There was no regular effect and significant effect on root mean square amplitude(RMS)and integrated electromyography(i EMG)of lower limb muscles under different sole hardness and falling height.However,among the muscle activation related to RMS,the maximum amplitude of EMG signal of rectus femoris(RF),lateral femoral muscle(VL)and anterior tibial muscle(TA)was higher than that of other muscles,and the normalized root mean square amplitude(RMS)was greater than that of other muscles,However,the root mean square amplitude(RMS)obtained by the normalized method of maximum value divided by the maximum value of EMG signal results in the lower degree of muscle activation of the above three muscles,so it is not possible to directly use a single muscle activation index to reflect the activation degree of the above three muscles.It should be combined with the standardized method and the maximum value of EMG signal to analyze together with the integral EMG The muscle contribution rate related to i EMG also showed that the rectus femoris(RF),lateral femoral muscle(VL)and tibialis anterior muscle(TA)accounted for the highest proportion of muscle contribution rate,which played a major role in the subjects to complete the landing action.Suggestions:1.When buying basketball shoes,the basketball shoes with moderate sole hardness should be selected,and the basketball shoes with too high or too low sole hardness should not be selected according to their own needs;2.In basketball,the joint angle should be increased when jumping to the ground,and the squatting speed should be reduced after touching the ground,so as to buffer the impact of the ground reaction force on the lower limbs and protect the joints;3.In basketball,we should take the initiative to increase the strength training of the straight thigh muscle,the lateral femoral muscle and the anterior tibial muscle,but we should ensure the coordinated development of the lower limb muscles,exercise the muscle strength around each joint,and improve the athletes' defense level against sports injury.