Analysis On The Biomechanical Characteristics Of Lower Limb Joints Of Backcourt Lateral Push Of Badminton Forehand

Objective:through the kinematics analysis,found that the forehand field lateral pedal movement technical characteristics,using reverse dynamics calculation lower limb knee internal mechanical characteristics,comparing different gender athletes in the forehand field pedal stride biomechanical characteristics,using surface EMG muscle power characteristics,a preliminary understanding of the step lower limb movement characteristics,and the possible cause of injury.Methods:Select 8 male subjects and 6 female subjects meeting the study criteria,divided into male one group(one step),male three groups(three consecutive steps),female one group(one step),and female three groups(three consecutive steps).The experimental instrument includes SONY(DSC-RX10M4)telephoto black card high-speed camera,KISTLER9287 C 3D force platform,NORAXON surface EMG wireless telemetry,shooting data are analyzed using SIMI Motion motion resolution software,force platform data are processed using Excel2020,and EMG data use Em The MEGAWIN3.0 software performs rectification,filtering,and smoothing.Matlab2018 b for normalization,formula calculation,statistical analysis using SPSS22.0,and mapping processing using Origin2019 b.Results:Kinematics:(1)MO versus MT: gravity displacement velocity MO is less than MT(P=0.038),ankle second peak angle is less than MT(P=0.01),hip displacement speed change range MO is less than MT(P <0.01),knee displacement speed change range MO is less than MT(P <0.01),ankle displacement speed range MO group is less than MT(P=0.049).(2)Compared with WO group and WO group: the WO group of center of gravity displacement in the front and rear direction is greater than the WT group(P=0.05),and the ankle displacement WO group is less than WT group(P=0.01),knee contact WO greater than WT(P <0.01),ankle displacement WO less than WT(P <0.01),knee minimum flexion WO greater than WT(P=0.042),ankle second peak WO less than WT(P <0.01),WO less than WT(P=0.042),and left and right WO greater than WT(P <0).01).The range of knee joint displacement velocity change in the vertical direction in the WO group is smaller than that in the WT group(P <0.0)1)The vertical range of ankle displacement velocity change in the WO group is larger than that in the WT group(P=0.01).(3)Comparison between MO and WO groups: gravity displacement MO larger than WO(P=0.01),range of gravity displacement velocity in front and rear MO larger than WO(P=0.021),ankle MO less than WO(P <0.01),ankle second peak MO less than WO(P <0.01),left and right MO hip displacement greater than WO(P=0.013),vertical ankle displacement MO less than WO(P=0.04 2)The change range of hip displacement speed in vertical direction is less than MO group than WO group(P <0.01),the change range of knee displacement speed in vertical direction in MO group is less than WO group(P=0.03),and the change range of ankle displacement speed in MO group is less than female group(P=0.011).(4)Comparison between MT group and WT group: center displacement MT group is greater than WT group(P=0.026),center displacement speed change range MT group is greater than WT group(P=0.034),knee contact angle MT group is greater than WT group(P=0.04),ankle contact Angle MT group is less than WT group(P <0).01),ankle off-ground angle MT group was less than WT group(P <0.01),and ankle second peak angle MT group was less than WT group(P<0.01).Kinetics:(1)compared with the male group: the peak ground reaction force in the anterior and posterior direction is less than the male group(P <0.01),and the peak ankle internal force in the vertical male group is less than the male group(P=0.011).(2)a female group compared with female three groups: front and back on the ground reaction force peak female group greater than female three groups(P=0.014),before the direction of female a group less than female three groups(P=0.02),hip force peak on female three groups greater than female group(P=0.05),before the hip force peak female group is greater than The female three groups(P=0.015),the peak knee force in anterior and posterior direction was greater than the female three groups(P=0.031),and the peak ankle force in anterior and posterior direction was greater than the three female groups(P=0.016).(3)male group compared with female group: left and right direction a male group less than female group(P=0.02),the vertical ground reaction peak in a male group less than the female group(P <0.01),front and back hip internal force peak in a male group less than female group(P=0.029),the vertical hip peak force a male group less than a female group(P <0.01),the male peak knee internal force in the three directions was less than the female group(P <0.01),and the male peak ankle internal force in the three directions was less than the female group(P<0.01,P=0.022,P=0.016).(4)Compared with the female groups in the male groups:the peak ground reaction force in the anterior and posterior direction is less than the female groups(P=0.032,P=0.042),the peak hip force in the anterior and posterior direction is greater in the male groups than the female groups(P=0.01),and the peak hip force in the vertical group is less than the female group(P=0.023),vertical The peak knee internal force in the three men was less than the female groups(P=0.035),and the peak ankle internal force in the left and right direction was less than the female groups(P=0.025).EMG RMS contribution:(1)Vastus lateralis: MO(19.8%),MT(20.07%),WO(18.42%),WT(20.79%);(2)Vastus medialis: MO(22.43%),MT(24.53%),WO(12.4%),WT(13.82%);(3)Rectus femoris: MO(17.55%),MT(15.94%),WO(18.83%),WT(21.38%);(4)Biceps femoris: MO(12.13%),WO(16.04%),WT(12.69%);(5)Semitendinosus: MO(9.6%),MT(10.57%),WO(11.9%),WT(11.41%);(6)medial Gastrocnemius: MO(7.76%),MT(6.73%),WO(12.14%),WT(11.07%);(7)lateral Gastrocnemius: MO(10.73%),MT(8.06%),WO(10.28%),WT(8.85%).Conclusion:(1)In the back stage of the forehand,the braking buffer is used first,and then the pedal extension starts the back position.Whether it is a single or continuous push step,there is no big change in the movement characteristics of the male group and the female group.(2)During knee flexion braking,the knee flexion Angle of the male group was smaller than that of the female group,the ankle dorsiflexion Angle of the female group was less than that of the boys’ group,and the landing stability of the boys was higher than that of the female group.(3)The male group increased the risk of lower limb joint injury after continuous pedaling,and the female group had a higher risk of lower limb joint injury at the first pedaling span than the three consecutive pedaling injuries.(4)The contribution rate of vastus lateral muscle,vastus medial muscle and rectus femoris is high in the whole ground touch stage,and the activation order is relatively advanced.The quadriceps muscle is the main force group in the ground touch stage.