The Lower Limb Joint Biomechanics Characteristics Of The Functional Ankle Instability During The Unanticipated Cutting

Purposes:This paper focuses on the study of the unilateral functional ankle instability group and the no ankle injury group in the anticipated and unanticipated modes of lateral cutting maneuvers.The biomechanical characteristics of the lower limbs in the lateral cutting maneuver were compared between the two groups,and the biomechanical differences between the two groups in the anticipated and unanticipated modes of cutting maneuver were investigated to analyze the causes of injury in the cutting maneuver in the functional ankle instability group,and to provide theoretical reference and experimental basis for the proper execution of the cutting maneuver.Methods:In this study,according to the Cumberland Ankle Instability Inventory(CAIT)questionnaire,combined with the drawer test and other methods,12 patients with right unilateral functional ankle instability were selected as the experimental group(FAI group).The age,height,weight and other morphological indicators of the subjects,as well as the years of sports participation,sports events,etc.,were matched to 12 subjects without ankle joint injury as the control group.The Vicon infrared motion capture and analysis system and the Kistler three-dimensional force platform were used to collect the kinematics and kinetic indicators of the two groups of subjects during the 45° cutting in the anticipated and unanticipated modes,respectively.In the anticipated mode,the subject runs on the force platform and directly performs a 45° cutting,in the unanticipated mode,when the subject runs through the infrared sensor device,the infrared sensor is triggered,and the connected 45° cutting indicates One of the lights,the 45° cross-cutting,and the straight running indicator will light up randomly,and the subjects will complete the corresponding actions according to the lighted indicator.A 2 ×2[group(FAI group and control group)× mode(expected and unexpected)]two-way repeated measures ANOVA was used for the collected kinematic and kinetic data.The main effects,interaction effects and simple effects of groups and different modes were analyzed,and the test level was α=0.05.Results:(1)Compared with the anticipated,the support period and buffer period were prolonged in the unanticipated cutting(P<0.05).(2)At the moment when the cutting touched the ground,the ankle dorsiflexion angle,ankle varus angle,ankle external rotation angle,and knee external rotation angle in the FAI group were all lower than those in the control group(P<0.05),the hip flexion angle in the unanticipated mode was greater than anticipated mode,hip internal rotation angle is less than anticipated mode(P<0.05).(3)At the time of the first peak of VGRF,the knee external rotation angle,ankle dorsiflexion angle and ankle varus angle in the FAI group were lower than those in the control group(P<0.05).In the unanticipated mode,the hip flexion angle is smaller than the anticipated mode,the hip abduction angle is larger than the anticipated mode,and the knee varus angle is larger than the anticipated mode(P<0.05).(4)At the second peak of VGRF,the knee internal rotation angle,ankle varus angle and ankle external rotation angle in the FAI group were lower than those in the control group(P<0.05).Hip flexion angle in unanticipated mode is smaller than anticipated mode(P<0.05).(5)At the moment when the toes were off the ground,The knee flexion angle and inversion angle were greater in the FAI group than in the control group,and the ankle inversion angle and external rotation angle were less than in the control group(P<0.05),the knee flexion angle was greater in the unanticipated mode than in the expected mode(P<0.05).(6)The first peak value of VGRF and the second peak value of VGRF in the unanticipated mode are smaller than the anticipated mode(P<0.05).(7)The peak moments experienced by the hip and ankle joints in the sagittal plane were greater in the FAI group than in the control group(P<0.05);the peak moments experienced by the knee joint in the sagittal plane were greater in the unanticipated mode than in the expected mode(P<0.05)Conclusion:(1)During the unanticipated cutting,the subjects would adjust their landing strategy and adopt a hip-led motion strategy.The main manifestations are prolonged lateral cut buffer period,increased hip flexion angle,knee and ankle joints are not in the optimal position for lateral cut movement,uneven forces,and increased risk of injury.(2)Those with functional ankle instability adopt a relatively conservative motion strategy during lateral cutting maneuvers.The main manifestations are limited ankle motion,inadequate energy absorption in the ankle during the lateral cut support period,and increased peak ankle moment,which threatens ankle stability.Combined with the unforeseen unfavorable position of the ankle during the lateral cut,the chances of recurrent ankle sprains increase.