The Biomechanical Performance Of Asymmetry Of Lower Limb Of The Knee Varus People In Vertical Jump

Purposes: The people of varus knee is easily to form arthritis,its incidence is two times higher than non-varus knee people,at first,its just unilateral performed.The lower limb asymmetry and the different kinds of Vertical Jump were tested in varus people and non-varus people.The objective was to explore the biomechanical characters during vertical jump in dominant lower limb and non-dominant lower limb,the difference of the varus people and non-varus people,to find the reasons of higher incidence of knee arthritis in varus knee people unilateral lower limb and the reasons of higher incidence of knee arthritis in varus knee people than non-varus people.The theoretical and experimental basis was provided for the knee arthritis and injury prevention in knee varus people.Methods:Twelve male subjects with knee varus were selected according to the formula of asymmetry and the method of forward single-leg jump, according to the age, height, weight, lower limb morphology characteristic,the formila of asymmetry matching 12 male subjects without knee varus.The kinematic data were captured by VICON motion capture system and the dynamic data were recorded by KISTLER force plate during vertical jump.The vertical jump are divided in to three kinds:squat jump(SJ)、count movement Jump(CMJ)、continuous vertical jump(CVJ).The instantaneous APGRF、MLGRF、VGRF,the max APGRF、MLGRF、VGRF and corresponding time,the peak degree and corresponding time、instantaneous degree of lower limb in three planes were captured in vertical jump.The dominant and non-dominant lower limb were compared in the kind of paried-samples T test and the dominant lower limb of varus knee people and non-varus people were compared in the kind of independent-samples t test.Results:①During the landing of SJ,there were significant differences between the dominant and non-dominant varus people in the Max coronal plane degree of hip、knee、ankle and the trend of knee varus degree、ankle valgus degree、hip abduction degree,and the varus and non-varus people in the Max coronal plane degree of hip、knee、ankle.②During the jumping of the CMJ,there were significant differences between the dominant and non-dominant varus people in the Max coronal plane degree of hip、knee、ankle and the trend of knee varus degree、ankle valgus degree、hip abduction degree,and the varus and non-varus people in the Max coronal plane degree of knee、ankle and the trend of knee varus degree、ankle valgus degree.During the landing of the CMJ,there were significant differences between the and the varus and non-varus people in the Max coronal plane degree of knee、ankle、hip and the trend of knee varus degree、ankle valgus degree、hip abduction degree.③During the landing of CVJ,there were significant differences between the dominant and non-dominant varus people in the Max coronal plane degree of hip、knee、ankle and the trend of knee varus degree、ankle valgus degree、hip abduction degree,and the varus and non-varus people in the Max coronal plane degree of hip、knee、ankle.Conclusions:Because of the varus knee angle of the people with asymmetric in both lower limb during different kinds of vertical jump,concentrate the dominant knee inside pressure to the middle side,with long time accumulation resulting in the medial articular surface wear.These maybe the reasons of varus knee people easier to form arthritis.Compare with the non-varus people,due to the hip、knee、ankle degree of knee varus people during different kinds of vertical jump who with lower limb asymmetry,concentrate the knee inside pressure to the middle side,these maybe the reasons of varus knee people easier to form arthritis than non-varus people.