Characteristics Of Foot Shape And Plantar Pressure Change And Recovery Of Long-distance Runners

Objective:Long distance running causes foot overload,resulting in changes in foot shape and foot pressure patterns.If don’t recover,the risk of injury may increase.It is important to recover from routine training for runners.The changes of foot morphology and residual effects can better explain the cause of lower extremity injury.The foot shape and foot pressure can reflect the structure and function of the foot completely from the static and dynamic aspects.However,there is a lack of comprehensive research on the foot of the marathon runners in our country at present.The purpose of this study is to study the end structure of the lower extremity-the foot,from the end structure of the lower extremity.To explore the changes of foot shape and plantar pressure after long distance running,as well as their residual effects,to provide biomechanical scientific basis for the evaluation of kinetics chain in sports rehabilitation.To provide a reference for rehabilitation clinical and scientific research workers to the overall understanding of marathon runners foot.Method:The foot function of 24 healthy male marathon runners was studied before,after,and 1 day after running.The first part was foot shape index(arch height,nomalised arch height,foot length,truncated foot length,navicular drop).The second part is plantar pressure(pressure,impulse,contact time,foot angle,foot balance).Comparison of the changes of foot parameters during the evaluation period by single factor repeated analysis of variance(ANOVA)Results:There was no significant change in navicular height,foot length and navicular drop.62.5% of the subjects showed a decrease in arch height.From pre-run,post-run to one day after running,the normalized plantar pressure in T2-T5 region first decreased and then increased(p < 0.01),M1,M2 region increased first and then decreased(p < 0.01),M1,M2 region pressure first increased and then decreased(p < 0.01),and the normalized plantar pressure in M1 and M2 region increased first and then decreased(p < 0.01).The impulse of M1 and M 2 increased first and then decreased(p < 0.01),and the impulse of T2-T5 region decreased first and then increased(p < 0.01).The impulse of M1 and M 2 increased and then decreased(p < 0.01).The total contact time increased first and then decreased(p < 0.05).The contact time of the initial landing period and the whole foot support period changed significantly with the time point(p < 0.05).After one day of running,foot balance increased in the middle support period(p < 0.05)and the push off period(p < 0.05).After 20 km running,the load distribution and size of plantar changed adaptively,the medial pressure of forefoot increased,the load migrated to the medial side,and recovered after one day’s rest.Conclusions:1.From before,after running to one day after running,20 km did not cause foot arch deformation and significant changes in foot structure.2.After long distance running,the pressure distribution and size of plantar increased,the cushioning function of foot decreased,the stress of foot was unbalanced,the inner force was larger than that of the outside,and the excessive pronation occurred,which could be recovered after one day’s rest.Risk factors for these changes were stress fractures,Achilles tendon disease,lower leg pain,patellofemoral pain syndrome,and ankle sprain.3.It is helpful to find out the mechanism of foot compensation or decompensation by studying the variation characteristics of plantar pressure time parameters.Comprehensive evaluation of static foot posture and dynamic foot function can be used as a tool to evaluate training load in order to avoid overtraining and reduce the risk of disease or injury.