The Influence Of Joint-fixed On The Static And Dynamic Stability Of The Erect Human Body

Objective: Based on the comparative study of the stability on the erect human under the static and dynamic conditions: for external disturbance adaptive training method for the elderly to preventing tumble; the pathological characteristics patients of the lower extremity joint; for a number of sports technical movement(muscles in a state of tension and the temporary fixation of joint) to understand the influence of joint fixed on stability of the erect human under the static ang dynamic conditions, providing the parameters of biomechanics and physiolog on stability of the erect human under the static stability and dynamic stability.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 the single joint and multi-joint fixed of lower extremity on the erect human under the static and dynamic conditions, including the Velocity_x and Velocity_y, RMS_Vx and RMS_Vy, and X-axis displacement rate(K_x) and other index, using repetitive measurement and analysis of variance to analize the influence of joint-fixed on stability of the erect human under the static and dynamic conditions.Results:(1) Under static condition, the stability of the anteroposterior is worse, the stability of the lateral decreased is better.(2) Under static condition, joint-fixed compared with non-fixed,the stability decreases: Hip and Knee fixed respectively compared with non-fixed, the anteroposterior and lateral sway are not significant( P>0.05); Ankle-fixed compared with non-fixed, the anteroposterior sway is significant(P<0.05), the lateral sway is not significant(P>0.05); Lower-fixed compared with non-fixed, the anteroposterior sway is not significant(P>0.05), the lateral sway is extremely significant(P<0.01).(3) Under static condition, between the stability of joint-fixed have some diference: Hip-fixed compared with Knee-fixed, the anteroposterior and lateral sway are not significant(P>0.05); compared with Ankle-fixed, the anteroposterior and lateral sway are significant(P>0.05); compared with Lower-fixed, the anteroposterior sway are not significant(P>0.05), the lateral sway is extremely significant(P<0.01). Knee-fixed compared with Ankle-fixed, the anteroposterior and lateral sway are significant(P<0.05); compared with Lower-fixed, the anteroposterior sway are not significant(P>0.05), the lateral sway is significant(P<0.05).(4) Under dynamic condition, the response to external force disturbance, joint-fixed compared with non-fixed,the stability decreases: Hip-fixed compared with non-fixed, the anteroposterior sway is not significant(P>0.05); Knee, Ankle and Lower fixed respectively compared with non-fixed, the anteroposterior sway are significantm(P<0.05).(5) Under dynamic condition, the response to external force disturbance, between the stability of joint-fixed have some diference: Hip-fixed compared with Knee-fixed, the anteroposterior sway is significant(P<0.05); compared with Ankle and Lower fixed respectively, the anteroposterior are extremely significant(P<0.01); Knee-fixed compared with Ankle and Lower fixed respectively, and Ankle-fixed compared with Lower-fixed, the anteroposterior are not significant(P>0.05).(6) Under dynamic condition, external force disturbance to go after 5s, joint-fixed compared with non-fixed,the stability decreases: Hip and Knee fixed respectively compared with non-fixed, the anteroposterior and lateral sway are not significant(P>0.05); Ankle-fixed compared with non-fixed, the anteroposterior and lateral sway are significant(P<0.05); Lower-fixed compared with non-fixed, the anteroposterior is extremely significant(P<0.01), the lateral sway is significant(P<0.05).(7) Under dynamic condition, external force disturbance to go after 5s, between the stability of joint-fixed have some diference: Under dynamic condition, external force disturbance to go after 5s, Hip-fixed compared with Knee-fixed, the anteroposterior and lateral sway are not significant(P>0.05); compared with Ankle and Lower fixed respectively, the anteroposterior are extremely significant(P<0.01), the lateral sway is not significant(P>0.05). Knee-fixed compared with Ankle-fixed, the anteroposterior is significant(P<0.05), the lateral sway is not significant(P>0.05); Compared with Lower-fixed, the anteroposterior is extremely significant(P<0.01), the lateral sway is not significant(P>0.05). Ankle-fixed compared with Lower-fixed, the anteroposterior and lateral sway are not significant(P>0.05).(8) Under dynamic condition, the response to external force disturbance, the stability of the anteroposterior is worse; external force disturbance to go after 5s, the stability of the anteroposterior is better.Conclusion:(1) In the visual and vestibular sensory shield stabilize the situation at the same level, the stability of the erect human decreases with joint-fixed under static condition or dynamic condition.Then when proprioceptive subject to interference, the stability of the erect human decreases, and the infliuence of anteroposterior stability of the erect human more than lateral stability.(2) Whether under static condition or dynamic condition: in the visual and vestibular sensory shield stabilize the situation at the same level, the infliuence of Ankle-fixed is maximum; Knee-fixed followed; the infliuence of Hip-fixed is minmum,so especially when Ankle strategy is limited, it should be through exercising training the interaction of Hip and Knee strategy, and improve their ability to maintain the stability of the erect hunman.Then in particular Ankle injury, substitution or hardening, should be through exercising training Hip and Knee proprioception, which together increase compensation for the Ankle proprioceptive.(3) Under the Upper-fixed condition, fixed lower, the equivalent of blocking the systemic joint proprioception and visual is shield, in order to maintain stability of the erect human, vestibular makes compensation for visual and proprioception. We can speculate that the infliuence of vestibular on the lateral stability of the erect human more than anteroposterior stability.