Biomechanical Analysis Of Lower Extremity Injuries During Habitual Landing In Runners With Different BMIs

Objective: to understand the basic biomechanical characteristics of lower limb movements of runners with different bmis when they land habitually by comparing the kinematic and dynamic characteristics of lower limb movements when runners with different bmis land habitually,so as to provide a basis for the prevention of running-related injuries.Methods: In this study,13 men with overweight BMI and 13 men with normal BMI were selected as subjects according to their research directions.The 3d motion analysis system(Vicon,Metrics Ltd.,Oxford,UK)and the 3d dynamometer(Kistler Type,9281 B,Kistler Instrument AG,Winterthur,Switzerland)were used to collect the kinematics and dynamics data of subjects' running gait synchronously,and the plantfoot pressure system(alskon international,dverweiser,Belgium)was used to collect the plantfoot pressure data of subjects.Motion Analysis' s own data acquisition and processing software CORTEX was used to process and export the lower limb kinematics and dynamics data,and Spss19.0 was used to conduct statistics and Analysis on the data.Results:(1)the BMI overweight compared with a normal BMI group of heel landing:compared with normal BMI groups,overweight ankle toe dorsiflexion Angle range,maximum toe flexion torque,maximum rotary torque,moment off the ankle external rotary torque,landing on time within the hip screw torque,off the moment of knee joint outreach torque is bigger,ankle dorsiflexion Angle,landing landing point moment ankle rotation Angle,off the moment outside the ankle smaller spiral Angle.Compared with the normal BMII group,the peak of total plantar pressure,the first toe,the(2-5)toe,the second metatarsal bone,the third metatarsal bone,the fourth metatarsal bone pressure peak,the third metatarsal bone,the fourth metatarsal bone area time pressure integral was greater.(2)comparison between the front foot landing and the heel landing in BMI superrecombination:compared with the heel landing,the average speed of the front foot landing is faster,and the time of support and buffering is less.Compared with the heel landing mode,the hip flexion Angle and knee flexion and extension Angle range of the front foot landing mode are smaller,while the knee knee bending Angle,knee joint external rotation moment,ankle joint toe flexion moment and ankle joint external rotation moment are larger.The loading rate of the maximum vertical ground reaction force in the heel landing mode is greater than that in the forefoot landing mode.The total pressure peak of the sole,the pressure peak of the inside and outside of the heel,and the time pressure integral of the inside and outside of the heel were larger than that of the front foot.(3)comparison between the front foot landing and the heel landing between groups with normal BMI: compared with the heel landing,the front foot landing was faster and took less time for buffering and support.Compared with the heel landing mode,the front foot landing mode,the range of the Angle of the inside and outside turn of the ankle joint,the range of the Angle of the dorsiflexion Angle of the toe,the extension moment of the knee joint at the moment of stepping off,the maximum flexion and extension moment of the knee joint at the supporting stage,the adduction Angle of the knee joint at the moment of stepping off,the flexion and extension Angle of the hip joint at the moment of landing,and the flexion and extension moment of the hip joint at the moment of landing are greater.At the moment of landing: the heel landing style is more prone to dorsiflexion of the ankle joint,the knee joint is more prone to abduction,the front foot landing style is more prone to toe flexion,the knee joint is more prone to adduction.The loading rate of the maximum vertical ground reaction force in the heel landing mode is greater than that in the forefoot landing mode.Compared with the forefoot landing mode,the total touchdown time of the heel landing mode,the medial heel landing time,the total pressure peak of the sole,the medial lateral pressure peak of the heel,and the time pressure integral of the inner and outer sides of the heel were greater,while the pressure peak and time pressure integral of the second metatarsal bone,the third metatarsal bone and the fourth metatarsal bone were smaller.(4)BMI overweight compared with normal group of forefoot landing: compared with normal BMI groups,BMI overweight knee flexion Angle range,from the moment of knee flexion Angle,landing on time,on the moment of knee extension torque,hip extensor off the moment of knee extension torque smaller,knee landing point out turning Angle is bigger.In the normal BMI group,the knee joint tended to turn inward,and the knee joint tended to turn outward.Conclusions:(1)according to the comparison of the heel landing modes of runners with different BMI,it can be seen that compared with the super-bmi recombination runners,the lower limb biomechanical characteristics of runners with normal BMI have less risk of lower limb injury.(2)according to the comparison of different landing modes of BMI super-recombination runners,it can be seen that compared with the heel landing mode,the lower limb biomechanical characteristics of the forefoot landing mode have less risk of lower limb injury.(3)by comparing the different landing modes of runners in the BMI normal group,it can be found that compared with the heel landing mode,the lower limb biomechanical characteristics of the forefoot landing mode have less risk of lower limb injury.(4)through the comparison of forefoot landing modes of runners with different BMI,it can be found that: in the forefoot landing mode,BMI has relatively little influence on the biomechanics of lower limbs.