Effect Of Personalized Insole Intervention On Lower Limb Biomechanics During Running

Purpose: With the increasing use of personalized insoles by star players,the personalized insole has received widespread attention in sports shoe manufacturers,and it has a positive effect on sports injury protection and body posture adjustment.Previous studies demonstrated that the arch support insoles can fit the shape of the medial longitudional foot arch,increase the contact area,and influence the redistribution of plantar pressure.While the wedge-shaped insoles can affect the knee joint motion pattern during daily movements.The purpose of this study was to investigate the biomechanical effects of personalized insoles on lower extremity during running before and after1-week adaptive and 6-week compulsory interventions,to provide guideline information for personalized insole customization.Methods: Nine male subjects with regular exercise habits and normal arch and knee function participated in this study.The personalized insoles were individually customized based on participants’ foot shapes.The control insoles using the same materials were flat insoles without any modification.The 8-camera Vicon motion system was used to capture participants’ lower limb kinematics,and the in-shoe plantar pressure measurement system was synchronized to measure plantar pressure.The subjective comfort and insole changes were collected by the Visual Analogue Scale(VAS)and thickness measuring instrument respectively.1-week adaptive and 6-week compulsory interventions were applied during the experimental process.Stress response was analyzed using one-way ANOVA following LSD method,while data before and after compulsory intervention were analyzed by a paired sample T-test.Results: The insole thickness gradually decreased during the intervention period(half-sole,before intervention: 5.14mm;1-week: 4.83mm;7-week: 4.81 mm.heelpiece,before intervention: 5.43mm;1-week: 4.87mm;7-week: 4.77 mm.)while the comfort evaluation improved(95.78&102.80&108.00).The personalized insole intervention adjusted the plantar pressure distribution.After the adaptive and compulsory interventions,the maximum pressure and pressure time integral in the middle-heel area increased significantly when compared to before-intervention(p<0.05).Comparison between before and after adaptive intervention showed that,the dorsiflexion angle increased slightly(p>0.05)while the knee flexion angle decreased at landing after the 1-week adaptive intervention(P<0.001).Besides the ankle dorsiflexion angle decreased(P<0.001)while the eversion angle increased(P<0.001),the knee adduction angle and abduction moment increased during the mid-support period(P<0.001&P=0.007).Comparison between before and after compulsive intervention showed that,both the ankle dorsiflexion angle and knee flexion angle decreased at landing after the 6-week compulsive intervention(P=0.028&P<0.001);in addition,the ankle dorsiflexion angle decreased(P=0.004)while the eversion angle decreased(P=0.024),the knee abduction angle and moment decreased during the mid-support period(P=0.028&P=0.003).Conclusion: With the increase of intervention time,the comfort evaluation of personalized insoles has steadily improved.The personalized insole arch support derived from personalized insoles can adjust the distribution of plantar pressure,especially the at medial heel,which is suggested to be a focus area for personalized insoles.Kinematic comparison between adaptive and compulsive interventions showed that these two interventions have the same influence at landing,whilst there is a difference in the frontal plane during the mid-support period.