| Objective:The purpose of this study was to investigate the effects of changes in sensory conditions and different forms of external postural interference on the upright stability of the human body,It provides theoretical support for people to face the interference of external factors to human posture and to further study the control of human upright posture.Methods: According to the experimental requirements,randomly selected 20 healthy male students,from the Soochow University Institute of Physical Education as subjects of the experiment,the subjects volunteered to participate in this experiment,and the purpose of this experiment did not know.By Kistler force platform(sampling frequency of 1000Hz),test-ing the stability of Changes of sensory conditions(keep your eyes open,close your eyes;stand on a platform,sponge pad)and interference of different forms of external forces(applied to the center of gravity in four directions: 5 and 10%BW,front,rear,left and right.),including the Velocity_x and Velocity_y,RMS_Vx and RMS_Vy,and Mos_x and Mos_y and other index,The experimental data are processed by Matlab7.0,and the results are compared and analyzed by SPSS20.0 statistical software.Results:(1)Under the change of sensory conditions,the vertical stability of the human body in both the front and right directions was decreased,and the vertical stability in the front and back directions was poor,and the stability in the left and right directions was better than that in the front and right directions.Comparison of NO with NC、PO、PC,The vertical stability of the human body in both the front and right directions was significantly lower than that in the left and right directions(P<0.01);Comparison of PC with NC、PO,The vertical stability of the human body in both the front and right directions was significantly lower than that in the left and right directions(P< 0.01);Comparison of NC with PO,The root-mean-square values of the mean sloshing velocity and velocity in the left and right directions of the human body increased,but there was no significant difference(P>0.05),but the mean sloshing velocity and velocity root-mean-square value of the front and rear directions both increased and had a very significant difference(P<0.01).(2)under the disturbance of external force,N0 compared with NC,the change of displacement in the direction before and after the force removal is significantly affected by:(P < 0.05),and the change of displacement in the immediate direction of the force in the left and right directions(P < 0.05).Comparison of NO with PO,there was a significant difference in the amount of displacement in the immediate direction and the left and right directions(P<0.05),and there was no significant difference in the mean sloshing speed and the root mean square value of velocity between the 5S and P>0.05;Comparison of PC with NO and PO,There were significant differences in the change of displacement and the mean sloshing velocity and root-mean-square value of the mean sloshing velocity and velocity of 5 s in the front and right directions(P < 0.05).(3)there is a significant difference in the changes of displacement,mean sloshing velocity and root-mean-square(RMS)between different external forces before and after the human body and in the left and right directions(P < 0.01).The change of displacement,the root mean square value of velocity and the mean sloshing velocity in the left and right directions were significantly different(P < 0.01),while the mean sloshing velocity in the front and back directions was significantly different(P < 0.05).The external force was applied to the front,the rear direction and the external force to the left.There is a significant difference in the postural stability between the front and left directions of the human body in the right direction(P < 0.01),and when the external force is applied to the front and the rear,Although there was significant difference in sloshing distance between front and rear directions(P < 0.05),there was no significant difference in mean velocity and velocity root mean square(RMS),and there was no significant difference in left and right directions(P > 0.05),when the external force was applied to the left side and the right side,there was no significant difference(P > 0.05).Although there is no significant difference in the mean square root of sloshing distance and velocity in the left and right directions(P > 0.05),there is a significant difference in the mean sloshing velocity in the left and right directions(P < 0.05.5)the magnitude of the external force and the interaction effect of the direction of the external force on the displacement change at the moment of the force removal.The mean sloshing velocity and the root mean square value of velocity at 5 s have a very significant effect on the change of displacement in the front and back directions(P < 0.01),but there is no significant effect on the change in the left and right directions(P > 0.05),and the interaction between the external force and the sensory condition has a significant effect on the change of the displacement immediately after the force is removed.The mean sloshing velocity and root-mean-square value of the deforce for 5s had no significant effect on the change of displacement in the front and right directions(P > 0.05),and the interaction effect between the direction of the external force and the sensory condition had no significant effect on the change of the displacement immediately after the removal of the force.The mean sloshing velocity and root-mean-square value of the deforce for 5s have no significant influence on the change of displacement in the front and right directions(P > 0.05),the magnitude of the external force,the interaction effect of the direction of the external force and the sense condition have no significant effect on the change of the displacement at the moment of the force removal.The change of mean sloshing velocity of 5 s in front and back direction is very significant(P < 0.01).The mean square root value of velocity of 5 s has a significant effect on the direction of forward and rear direction(P < 0.05),and the change of displacement is in the left and right directions.There was no significant difference in the mean sloshing velocity of 5 s in the left and right directions(P > 0.05),and there was significant difference in the root mean square(RMS)value in the left and right directions of the mean square value of the removal force in the left and right directions(P < 0.05).Conclusions:(1)Visual constraints and proprioceptive limitations both reduce the vertical stability of the human body and the effect of the front-to-rear direction is greater than that of the left and right directions.When the two work together,the stability of the erection decreases more significantly.(2)Under the interference of external forces,the stability of the body's front and right directions and posture decreased more significantly,the shielding vision would change the sloshing distance in the front and rear directions,while the vestibular sense would change the sloshing distance between the front and right directions,and the left and right directions of the vestibule sense would change.The stability of posture is sensitive to the change of interference intensity,the intensity of interference is increased,the change of front and back direction and left and right direction is more remarkable,and the front and back direction is larger than the left and right direction.(3)Compared with frontal axis and sagittal axis,the external force applied to the sagittal axis has different balance recovery modes.(4)the interaction between the external force and the direction of the external force has significant differences in the vertical stability in the front and back directions.The interaction effect of sensory interference and single mechanical interference has no effect on the vertical stability,but the interaction effect of sensory interference and multiple mechanical interference has an effect on the vertical stability. |
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