| Purposes:In this study,the functional ankle instability group and the control group were given lower extremity muscle fatigue intervention to compare the neuromuscular control and lower extremity movement performance of the two groups of people before and after fatigue when their body posture was disturbed by external disturbances.The related mechanism of postural adjustment in patients with joint instability under the influence of lower limb muscle fatigue provides relevant theoretical basis and experimental reference for the study of human posture stability in patients with functional ankle joint instability.Methods:In this study,12 subjects with unilateral functional ankle instability were selected as the experimental group by means of the Ankle Joint Functional Assessment Tool(AJFAT)and the drawer test.The age,height,weight,lower limb morphological indicators and other characteristics of the subjects in the group were matched with 12 subjects without ankle joint injury as the control group.Infrared high-speed motion capture system,KISTLER three-dimensional force measuring platform and Italian Cometa surface electromyography analysis system,respectively,when two groups of subjects faced external force interference,their fatigue performance before and after standing on two feet and standing on one foot.The human body stability,the peak joint angle of the lower limbs and the integral iEMG values of the related muscles in the APAs stage and the CPAs stage were collected.Two-way repeated measures ANOVA was used to compare the differences of all the collected data on different sides and before and after fatigue.Results:(1)When standing on both feet in the face of external force interference,the difference in RMS_Vx between the FAI group and the control group was statistically significant(P<0.05),but there was no statistical difference in the stability in the left and right directions between the two groups Significant difference(P>0.05);the stability in the front and rear,left and right directions before and after lower limb muscle fatigue in the two groups were significantly different(P<0.05).(2)When standing on one foot in the face of external force interference,the differences in the stability in the anterior and posterior directions were statistically significant between the affected side and the healthy side of the FAI group,the affected side and the matched side of the control group(P<0.05).The difference between before and after fatigue on each side was statistically significant(P<0.05),and the difference in RMS_Vy between the affected side and the matched side of the control group before and after fatigue was not statistically significant(P>0.05).(3)When standing with both feet in the face of external force interference,the difference between the affected side of the ankle joint and the matched side of the affected side was statistically significant(P<0.05),and the difference of the peak knee angle between each side was statistically significant There was statistical significance(P<0.05);the difference of the peak ankle and hip angles before and after fatigue on each side was statistically significant(P<0.05),and there was no statistical difference in the peak knee angle between the unaffected side and the unaffected side before and after fatigue.academic significance(P>0.05).(4)When standing on one foot in the face of external force interference,the differences in the peak ankle angle between the affected side of the FAI group and the healthy side,the affected side and the matched side of the control group were all statistically significant(P<0.05).、The difference of the peak knee angle between the affected side and the healthy side of the FAI group and between the affected side and the matched side of the control group was statistically significant(P<0.05).The difference was statistically significant(P<0.05),and there was no significant difference in the peak knee angle between the affected side and the healthy side before and after fatigue(P>0.05).(5)When standing on both feet in the face of external force interference,in the APA stage,there was no significant difference in iEMG of each muscle between each side(P>0.05),rectus femoris,tibialis anterior and long head of biceps femoris.The differences of iEMG before and after fatigue on each side were statistically significant(P<0.05).In the CPAs stage,the iEMG of the tibialis anterior muscle and the rectus femoris muscle were significantly different on each side(P<0.05).Significance(P<0.05).(6)When standing on one foot in the face of external force interference,in the APA stage,there was no significant difference in the iEMG of each muscle between each side(P>0.05).The difference between the two groups before and after fatigue was statistically significant(P<0.05).In the CPAs stage,the iEMG of the long head of the biceps femoris and the lateral head of the gastrocnemius was between the affected side and the healthy side,and the affected side and the matched side of the control group,respectively.The difference was statistically significant(P<0.05),and the differences in iEMG of the long head of biceps femoris and tibialis anterior muscle before and after fatigue between the affected side and the healthy side,the affected side and the control group were statistically significant(P<0.05).Conclusions:(1)In the face of external disturbances,there are significant differences in the postural control ability of functional ankle instability patients compared with healthy people.Especially when standing on one foot,the affected side of functional ankle instability patients is compared with their healthy side.Compared with healthy people,it shows a marked deficit in postural control.(2)Whether it is functional ankle instability or healthy people,after lower limb muscle fatigue,when faced with external disturbances,the phenomenon of reduced human body stability,transfer of balance strategy from distal to proximal,and increased muscle activation occurs.The impact on the affected side was more pronounced in patients with functional ankle instability,which also reflects that exercise fatigue is an important factor that increases the risk of injury during exercise in patients with functional ankle instability. |
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