| Research purpose:Landing movements are extremely common in sports,but due to the large ground reaction force,landing can easily cause sports injuries.Moreover,different landing directions result in different biomechanical responses and neuromuscular control information in the lower limbs.At the same time,patients with functional ankle instability have different movement patterns compared to healthy individuals due to structural damage,proprioception disorders,and other reasons.Therefore,this article conducts an experimental study on three different directions of landing movements between subjects in the unilateral functional ankle instability(FAI)group and the healthy control group.It discovers the differences in lower limb biomechanical indicators between the functional ankle instability group and the control group in different landing directions,filling the gap in landing experiments in different directions for functional ankle instability patients and clarifying the reasons for injury occurrence,Provide theoretical basis and practical reference for the prevention and treatment of functional ankle instability,as well as for sports rehabilitation or training.Research methods:In this study,12 male patients with unilateral functional ankle instability on the right side were selected as the experimental group(FAI group)based on the Cumberland Ankle Instability Inventory(CAIT)questionnaire and the front drawer test.According to morphological indicators such as age,height,weight,and years of physical activity,12 male patients without ankle injury were matched as the control group.The Vicon infrared motion capture and analysis system and the Kistler three-dimensional dynamometer were used to collect the kinematic and dynamic indicators of the forward,lateral,and oblique landing movements of the two groups of subjects.The platform support point for the forward landing action is in front of the center of the force platform(i.e.,the landing point)(slightly deflecting the support foot to ensure the correct posture of landing),the platform support point for the oblique landing action is 45 ° in front of the center of the force platform,the platform support point for the lateral landing action is on the positive side of the center of the force platform,and the platform edge is 15 cm from the edge of the force platform.In all experiments,the subjects were required to support their feet on a platform with a single foot,and the test foot(the affected side of the FAI group and the matching side of the control group)landed on a single foot in the center of the force table.The landing was stable without shifting,changing steps,or excessive deviation of the center of gravity,and the test foot was stably supported for 3s.Apply 2 to the collected kinematics and dynamics data X 3[Group(FAI group and control group)X Mode(forward fall,side fall,oblique fall)]Double factor repeated measurement analysis of variance,analyzing the main effects,interactive effects,and simple effects of kinematics and dynamics data in different groups and modes,and testing the level α=0.05。Research results:(1)In the comparison of lower limb joint angle at the moment of touchdown,the FAI group had smaller hip joint flexion angle,greater hip joint abduction angle and greater ankle joint varus angle than the healthy control group at the moment of touchdown(P<0.05).In addition,the hip flexion angle of FAI group and healthy control group showed forward fall>side fall,oblique fall>side fall(P.(2)In the comparison of lower limb joint angle at the time of buffer completion(the maximum moment of knee flexion of the test leg),the hip and knee flexion angle of FAI group was lower than that of the healthy control group(P<0.05),and the ankle varus angle was higher than that of the healthy control group(P<0.05).In addition,the flexion angle of the hip joint is forward fall>side fall,oblique fall>side fall(P<0.05),there is no statistical difference between forward fall and oblique fall(P>0.05),the hip joint abduction angle is side fall>oblique fall>forward fall(P<0.05),the ankle joint back flexion angle is side fall>forward fall,lateral fall>oblique fall(P<0.05),and there is no statistical difference between forward fall and oblique fall(P>0.05).(3)In the comparison of the characteristics of angle changes from the time of touchdown to the time of buffer completion,the changes of hip and knee flexion angle in FAI group were less than those in the healthy control group(P<0.05),and the changes of ankle varus angle were greater than those in the healthy control group(P<0.05).In addition,the change of ankle dorsiflexion angle was lateral fall>oblique fall,lateral fall>forward fall(P<0.05),and there was no statistical difference between forward fall and oblique fall(P>0.05).(4)In the comparison of the maximum angle of ankle varus and its corresponding time characteristics,the maximum angle of ankle varus in FAI group was greater than that in the healthy control group,and the corresponding time of the maximum angle of ankle varus was earlier than that in the healthy control group(P<0.05).(5)In the comparison of the peak value and corresponding time characteristics of the ground reaction force in the inner and outer directions,the peak value of the ground reaction force in the different landing directions is side fall>oblique fall>forward fall(P<0.05).In terms of the characteristics of peak outward ground reaction force,forward fall>side fall,forward fall>oblique fall(P<0.05),there was no statistical difference between side fall and oblique fall(P>0.05).The peak outward ground reaction force corresponds to the time characteristics of front fall>side fall,front fall>oblique fall.The time of front fall is earlier than that of side fall and oblique fall(P<0.05).There is no statistical difference between side fall and oblique fall(P>0.05).In the comparison of the time corresponding to the peak value of vertical ground reaction force,the side fall is greater than the front fall,and the front fall time is earlier than the side fall oblique fall(P<0.05).(6)At the peak time of vertical ground reaction force,the extension moment of knee joint in sagittal plane in FAI group and healthy control group was greater than that in FAI group(P<0.05).At the moment of buffer completion(the maximum moment of test leg flexion),the sagittal extension moment of knee joint in FAI group and healthy control group was greater than that in FAI group(P<0.05).In the comparison of the peak moment of the sagittal coronal plane of the hip,knee and ankle,the plantar flexion moment of the lateral landing ankle joint is greater than that of the forward landing ankle joint(P<0.05).Research conclusions:(1)People with functional ankle instability exhibit a more"stiff" landing motion(smaller hip knee flexion angle)during landing in different directions,which is not conducive to buffering ground reaction forces,thereby posing a threat to the stability of lower limb joints,especially the ankle joint.(2)Compared to forward landing,lateral landing and oblique landing exhibit smaller hip and knee flexion angles,greater ankle dorsiflexion angles,and plantar flexion moments at different times of landing.The lower limbs cannot adequately cushion against the impact of ground reaction forces on the body,with lateral landing being more prominent.(3)Due to limited ankle function,as well as the unfavorable buffering position of the ankle joint when landing sideways,functional ankle instability has a large ground reaction force and an imbalance between the inner and outer sides,leading to an increased risk of ankle joint re sprain. |
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