Correlation Analysis Of Foot Kinematics Characteristics With Different Arch Heights And Lower Limb Stress Fractures

Objective: The foot is the part of the human body that directly contacts the ground.Through the special structure of the foot arch,it plays an important role in absorbing ground impact,supporting body weight,and gait propulsion.This study intends to analyze the relationship between the foot kinematics characteristics and arch height of the newly enlisted fighters before the start of training,and explore the influence of the changes of the foot arch height on the kinematics characteristics of the foot.Then analyze the arch height and foot kinematics characteristics of soldiers who suffered lower extremity stress fractures during three months of common subject training,and explore the relevant foot biomechanical factors that may cause lower extremity stress fractures.Methods: Using prospective research methods,129 new recruits from a certain unit of the Chinese Army in 2019 were selected as the research objects.Before starting the common subject training,the recruits’ foot print images were collected through the capacitive plantar pressure measurement system to calculate the arch index.Analyze the kinematic characteristics of the foot through the dynamic gait posture analysis system(Right Gait & Posture).The relevant parameters include the ground elevation angle,the ground inversion angle,the ground elevation angle,the valgus amplitude,the ground speed,and the ground eversion speed.Divide the maximum and minimum arch index into three equal width intervals.The larger the arch index,the lower the arch.A total of 216 lower limb samples of 108 people were divided into higher arch group(n=50),middle arch group(n=80)and lower arch group(n=86),and the difference of foot kinematics characteristics between different arch height groups was compared.The orthopedic surgeons who have been systematically trained follow up the whole course of the recruits’ common training,and diagnose and record the cases of lower limb stress fracture.Finally,the differences in arch height and foot kinematics characteristics were compared between the recruits in the fracture group(n=19)with lower extremity stress fracture and the control group(n=79)without any lower extremity training injury,and the biomechanical characteristics of the feet of the soldiers with lower extremity stress fracture were analyzed.Use SPSS 20.0software for data analysis,when P<0.05,the difference is considered to be statistically significant.Use K-S test to analyze the normality of the data;normal distribution measurement data is represented by ?X±s.When analyzing the foot kinematics characteristics under different arch heights,the overall comparison uses the analysis of variance,and the comparison between the groups uses the Tukey HSD test.Non-normally distributed variables use Kruskal-Wallis H test.In the analysis of the biomechanical characteristics of the foot in the fracture group,the independent-sample t test was used for the comparison between the parameters of the normal distribution;the Mann-Whitney U test was used for the parameters of the non-normal distribution.Results: 1.By comparing the foot kinematics characteristics of fighters in different arch height groups,it is found that the strike-inversion angle and the toe-off angle show a trend of decreasing with the increase of the arch height,and the strike-inversion angle of the higher arch group is(11.76°± 3.85°)was significantly different from the other two groups(lower arch group: 14.37°±4.48° middle arch group: 14.03°±4.46°).The toe-off angle was significantly different between the higher arch group(61.94°±4.09°)and the lower arch group(65.29°±6.17°).The eversion extent was significantly different between the higher arch group(11.06°±3.27°)and the middle arch group(12.57°±3.51°).There was no difference in the heel-strike angle,etrike-pitch velocity and eversion velocity among the groups.2.By comparing the foot arch index at rest and the foot kinematics characteristics parameters during walking between the fracture group and the control group,the biomechanical characteristics of the feet of patients with stress fractures were analyzed.The results showed that the average rank of the arch index of the fracture group was 41.00,which was significantly lower than the average rank of the control group(55.34),P<0.05.The toe-off angle of the fracture group(61.59°±5.51°)was significantly lower than that of the control group(64.79°±4.79°),P<0.05.The average rank of eversion velocity in the fracture group was 40.17,which was significantly lower than the average rank of 55.59 in the control group,P<0.05.There was no significant difference between the two groups in the heel-strike angle,strike-inversion angle,eversion extent,etrike-pitch velocity.Conclusion:1.Changes in the arch height will cause significant changes in the strikeinversion angle,toe-off angle,eversion extent,which will change the biomechanical function of the foot.2.Warriors with stress fractures have the characteristics of higher arches,lower toeoff angle and lower eversion velocity.Among them,the lower toe-off angle and lower eversion velocity may be caused by high arches.