The Biomechanical Characteristics Of The Ankle Instability Before And After Fatigue

Purposes: In this study,the subjects of unilateral functional ankle instability and ankle joint injury were tested before and after fatigue,and the biomechanical characteristics of the two groups were analyzed.To explore the biomechanical differences between the unilateral functional ankle instability and the ankle joint injury in the fall and landing buffer,and the effects of fatigue factors on the drop characteristics of the subjects in both groups,and to analyze the functional ankle instability the reasons are easy to damage,and to provide a theoretical basis for prevention of ankle joint injury during exercise involving fatigue.Methods: Twelve male FAI subjects were selected according to the Ankle Joint Functional Assessment Tool(AJFAT)questionnaire and the drawer test.According to the age,height,weight,Training items,lower limb morphological indicators and other characteristics of 12 male ankle injury were selected as the control group.The VICON infrared motion capture and analysis system and KISTLER three-dimensional dynamometer were used to collect the kinematic and kinetic parameters of the two groups before and after fatigue.The drop height was 40 cm,and the collected Kinematic and kinetic data were compared between different groups and before and after fatigue.Two-factor repeated measurements were used to measure variance analysis.Results :(1)The difference between the maximum dorsiflexion angle,the maximum dorsiflexion angle and the landing stability time was statistically significant(P <0.05).(2)There were statistically significant differences in the peak time between the outward direction and the peak time in the vertical direction,and the difference between the peak time and the loading rate in the vertical direction(P <0.05).(3)There were statistically significant differences between the peak time and the loading rate in the vertical direction(P <0.05).(3)The maximum dorsiflexion angle,the maximum dorsiflexion angle corresponding to the time,landing stability time before and after thedifference was statistically significant(the difference between the two groups)was statistically significant(P <0.05).(4)The peak of the ground reaction force in the vertical direction,the peak of the ground reaction force and the loading rate in the backward direction were statistically significant(P <0.05);(5)The results of simple effect analysis showed that FAI group was 100 ms before landing in the case of fatigue,and the interaction between fatigue and fatigue was statistically significant(P <0.05).FAI group had a greater than that of the control group(P <0.05).Before the fatigue of the FAI group,the plantar flexion angle was less than that before fatigue,(P <0.05).(6)The interaction between group and fatigue had statistically significant effect on peak VGRF(P <0.05),and there was no significant difference between the two groups(P<0.05)The results of simple effect analysis showed that the peak VGRF of the control group was less than that before fatigue(P <0.05).Conclusion:(1)Functional ankle instability and healthy control group showed different biomechanical characteristic in the process of single leg landing,mainly in the knee flexion angle,the first 100 ms knee flexion angle,dorsiflexion maximum angle,landing stability time(2)Unilateral FAI group compared with the control group,bearing a greater loading rate,the vertical direction of the GRF peak appears shorter and the maximum angle of the extension of the ankle maximum angle,especially after fatigue Legs fall to the ground process,the affected side of the moment to turn the angle is relatively large,which is caused by ankle instability is an important reason for injury.(3)Compared with before fatigue the falling of one leg,the body will do a good job by knees in advance to improve the knee flexion angle to cushion the impact of the impact after fatigue,which is an adaptation to fatigue,but ankle Stretch the maximum angle of the corresponding time longer,touch the angle when the angle becomes larger,these are important causes of lower limb injury caused by fatigue.