| Objective: Ankle joint injury is a common injury in sports,which is characterized by pain,swelling,fatigue,ankle instability and loss of control and other symptoms.Therefore,the injury of the ankle joint will have a certain impact on the postural stability of the human body.This study compared the differences in maintaining postural stability between the FAI group and the control group from the perspective of electromyography and kinematics,and explored the characteristics of maintaining postural stability in the FAI group,so as to provide scientific basis and theoretical support for the diagnosis,treatment and rehabilitation training of FAI.Methods: In this study,15 male functional ankle instability subjects who met the inclusion criteria were selected as the experimental group(FAI group),and 15 male subjects without ankle pain symptoms were selected as the control group.Qualisys high-speed infrared motion capture system and DELSYS EMG acquisition system were used to synchronously collect EMG indexes and kinematics indexes of subjects in the process of front,back,left and right sliding while standing.Comparative analysis by slide forward,backward,left,right,FAI group and the control group of CoM maximum displacement,the maximum speed CoM,CoM maximum acceleration and joint Angle and position of lower limbs three joint reflection phase phase(disturbance after 100 ms to happen before 50 ms),posture adjustment stage(50 ms to 200 ms after disturbance)and position stable stage(200 ms to 350 ms after a disturbance)different stages of lower limb muscle integral electrical and electrical activation.Results:(1)When subjected to left sliding,the maximum displacement of COM in FAI group was greater than that in control group(P<0.05).The maximum velocity of COM in FAI group was higher than that in control group when subjected to front and back sliding(P<0.05).The maximum acceleration of COM in the FAI group was less than that in the control group(P<0.05).(2)Under the interference of different directions,the integral EMG of lateral vastus muscle in FAI group was greater than that in control group.During the postural adjustment stage,the integral EMG of the left lateral femoris muscle in the FAI group was higher than that in the control group(P<0.05).During the postural adjustment stage,the integral EMG of right lateral femoris muscle in FAI group was higher than that in control group(P<0.05).During the postural stability stage,the integral EMG of right rectus femoris muscle and right lateral femoris muscle in FAI group was higher than that in control group(P<0.05).When subjected to left slide,the integral EMG of left rectus femoris muscle and left and right lateral femoris muscle in FAI group were higher than those in control group at the postural stability stage(P<0.05).During the postural adjustment stage,the left rectus femoris muscle and the left vastus lateralis muscle in FAI group were greater than those in control group(P<0.05).In the stable postural stage,the left and right rectus femoris muscle and left vastus lateralis muscle in FAI group were greater than those in control group(P<0.05).(3)Under the sliding of different directions,the FAI group showed the dependence on the coordination of the knee and hip muscles and the compensatory effect on the activation degree of the healthy ankle flexor muscles.During the postural reflex stage,the activation degree of biceps femoris on the right side of flexor geniculus and extensor geniculus lateralis on the left side and the medial gastrocnemius on the left side of flexor malleolus in FAI group was higher than that in control group(P<0.05).In the postural reflex stage,the activation degree of biceps femoris at the right side of flexor geniculus and the vastus lateralis at the left side of extensor geniculus in FAI group was higher than that in control group(P<0.05).At the postural stability stage,the activation degree of the left soleus muscle of the flexor malleolus muscle in FAI group was higher than that in the control group(P<0.05).During the postural reflex stage,the activation degree of the left biceps femoris of the flexor geniculus muscle in the FAI group was greater than that in the control group.During the postural adjustment stage,the activation degree of biceps femoris on the right side of flexor geniculus muscle,vastus lateralis on the right side of extensor geniculus muscle and tibialis anterior muscle on the left side of flexor ankle muscle in FAI group was higher than that in control group(P<0.05).At the postural stability stage,the activation degree of the left and right gastrocnemius of the flexor malleolus muscle,the left rectus femoris of the hip flexor muscle,the left lateral vastus of the lateral vastus muscle and the left tibialis anterior muscle of the extensor malleolus muscle in the FAI group was higher than that in the control group(P<0.05).During the postural reflex stage,the medial activation of the left flexor malleolus muscle in FAI group was higher than that in control group(P<0.05).In the postural adjustment stage,the activation degree of the left lateral vastus of the geniculus extensor muscle in FAI group was higher than that in control group(P<0.05).At the postural stability stage,the activation degree of the left soleus muscle of the flexor ankle muscle and the right rectus femoris and the left lateral femoris muscle of the hip flexor muscle in the FAI group was higher than that in the control group(P<0.05).(4)When sliding in different directions,the maximum Angle difference between the FAI group and the control group was more obvious when sliding forward.Under forward sliding,left ankle valgus was greater in FAI group than in control group,while dorsiflexion of left and right ankle and internal rotation of right ankle were less than in control group(P<0.05).The flexion and adduction of the left knee joint were greater than those of the control group,while the external rotation of the left knee joint and the adduction,flexion and external rotation of the right knee joint were less than those of the control group(P<0.05).Left hip adduction,right hip adduction and internal rotation were greater than those in the control group,while left hip rotation was less than those in the control group(P<0.05).Conclusion:(1)The instability of right ankle joint may enhance the neuromuscular control of the left supporting leg in the FAI group,while the ability of the right supporting leg to adjust posture is decreased.The instability of the left supporting leg is greater,while the stability of the right supporting leg is enhanced.(2)Changes in the structure around the ankle joint greatly affect the stability of the ankle joint,and the muscle groups around the ankle joint can regulate the balance through synergistic action.In response to interference from different directions,there was no significant difference in the integral EMG of tibial anterior muscle between the FAI group and the control group.However,in the FAI group,the geniculus extensor lateral femoris muscle and the hip flexor rectus femoris integrator EMG played an important role in the process of posture adjustment.Moreover,the FAI group showed an dependence on the coordination of the knee and hip muscles and a compensatory phenomenon on the activation degree of the healthy ankle flexor muscles.(3)In the face of different interference directions,people’s joints will have different coping strategies to maintain body balance.Moreover,when subjected to forward sliding,the maximum Angle difference was more significant in the FAI group than in the control group. |
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