| Background and purpose: In recent years,the high incidence of flat feet among female college students should arouse social attention.Among them,Flexible Flatfoot(FFF)is a functional change,and its arch is reversible,and the arch height changes with or without weight.Taking targeted interventions at this stage is crucial to prevent it from further developing into structural rigid flat feet.The decrease of the medial longitudinal arch of the flexible flat feet is mainly caused by the weak muscles and tendons of the feet and lower limbs.Therefore,exercise intervention methods focusing on strengthening the muscle function may be one of the first choices for the prevention and treatment of flexible flat feet.However,at present,the research on flatfoot exercise intervention is quite limited.The outstanding problem is that flatfoot is not classified,which weakens its reference value.Effective exercise intervention programs for flexible flat feet are in urgent need of improvement.Therefore,this study conducted a 16-week training of the muscle function of the feet and lower limbs for female college students with flexible flat feet.The effect of intervention was observed from the changes in arch shape and gait,and the realization mechanism of the intervention effect was analyzed from the characteristics of muscle contraction.The research conclusions will provide more valuable theoretical basis and practical guidance for people with flexible flat feet.Research method: In this study,12 female college students with normal feet(normal arch group)and 24 female college students with FFF were selected by standard navicular height index method,foot print three-line method combined with tiptoe test and toe elevation test,and randomly divided them.It is the FFF intervention group and the FFF control group.The FFF intervention group received 16 weeks of muscle function training for the feet and lower limbs,while the FFF control group did not change their original lifestyle.The subjects were subjected to the following tests before and after the experiment:(1)Measurement and evaluation of the arch of the foot: Standardized Navicular Height truncated(NNHt),Footprint Proportion Index;(2)Walking test: Qualisys infrared motion capture The system,Kistler three-dimensional force plate,and Noraxon surface electromyography instrument synchronously collect the kinematics,dynamics,and surface electromyography data of the subjects' lower limb joints(hip,knee,ankle)while walking.The test data was statistically processed by SPSS17.0 software,the difference between the groups before and after the experiment was analyzed by one-way analysis of variance,and the difference between the groups before and after the experiment was analyzed by the paired sample t test.The significance level was P<0.05.Result:1.Changes in foot arch morphology: Compared with the normal arch group before the experiment,the NNHt and footprint ratio index of the flexible flat foot group were significantly lower(P<0.05).After the experiment,the NNHt and foot print ratio index of the flexible flat foot group were still significantly lower than the normal arch group(P<0.05),but the two parameters of the FFF intervention group were significantly greater than before the experiment(P<0.05),and greater than the same period FFF The control group(P<0.05),and the FFF control group's footprint ratio index was significantly lower than before the experiment(P<0.05).2.Changes in gait:(1)Changes in kinematic parameters: [Time and space parameters] Before the experiment,the percentage of the double support period in the flexible flat foot group was significantly lower than that in the normal arch group(P<0.05).After the experiment,the percentage of the dual support period in the FFF intervention group was significantly greater than that before the experiment(P<0.05),while the FFF control group also showed a step width that was significantly greater than before the experiment(P<0.05),and greater than the FFF intervention group and normal at the same time.Arch group(P<0.05).[Joint angle parameters] Compared with the normal arch group before the experiment,the flexible flat foot group had a smaller hip adduction angle during the support period,a larger hip flexion angle when the toe was on the ground,and a smaller ankle plantar flexion angle when the toe was off the ground.(P<0.05).After the experiment,the hip adduction angle of the FFF intervention group when the toe touched the ground was significantly greater than that of the FFF control group,and the ankle plantar flexion angle when the toe was off the ground was significantly greater than before the experiment and greater than the FFF control group(P<0.05).The FFF control group also showed that the knee abduction angle and ankle plantar flexion angle when heel touched the ground were significantly smaller than the normal arch group(P<0.05),and the ankle plantar flexion angle was significantly smaller than the pre-experiment and FFF intervention group(P<0.05);The angle of knee external rotation when the toe is on the ground is significantly smaller than that of the normal arch group(P<0.05);the angle of hip flexion and ankle dorsiflexion when the heel is off the ground are significantly greater than that of the normal arch group,and the angle of knee external rotation is significantly smaller and smaller than before the experiment The normal arch group and the FFF intervention group(P<0.05);the hip abduction angle when the toes were off the ground was significantly greater than the normal arch group(P<0.05).In short,the kinematic parameters of the FFF intervention group were not significantly different from the normal arch group after the experiment(P>0.05).(2)Changes in dynamic parameters: [Ground reaction force] Before the experiment,compared with the normal arch group,the GRF-backward peak of the flexible flat foot group during the support period was larger,and the GRF-inward and vertical first peak peak time was smaller(P< 0.05).After the experiment,the peak ground reaction force in the front and back direction and inward of the FFF control group was significantly greater than that of the normal arch group,and the peak time of the outward ground reaction force was significantly shorter than that of the FFF intervention group and the normal arch group(P<0.05).[Peak torque of lower extremity joints] Before the experiment,compared with the normal arch group,the peak moments of hip abduction,knee external rotation,and ankle dorsiflexion in the flexible flat foot group during the support period were significantly larger(P<0.05).After the experiment,the peak hip abduction torque in the FFF intervention group was significantly smaller than before the experiment and smaller than the FFF control group(P<0.05).However,the FFF control group also showed that the peak knee flexion torque was significantly greater than the FFF intervention group and the normal arch group(P<0.05).[Displacement of plantar pressure center] Before the experiment,the front and back displacement of the plantar pressure center of the flexible flat foot group was significantly greater than that of the normal arch group(P<0.05).After the experiment,the front and back displacement of the FFF intervention group was significantly greater than that of the FFF control group(P<0.05),and the FFF control group also showed significantly greater lateral displacement than the normal arch group(P<0.05).In short,the dynamic parameters of the FFF intervention group were not significantly different from the normal arch group after the experiment(P>0.05).(3)Changes in electromyographic parameters: Before the experiment,compared with the normal arch group,Flexible flat feet group had a lower activation rate of semitendinosus muscle in the early stage of support,and a higher activation rate of lateral femoris muscle in the middle stage of support(P<0.05).After the experiment,the FFF control group also showed that the activation rate of the gastrocnemius and biceps femoris at the pre-support stage was significantly greater than that before the experiment and was significantly greater than that of the normal arch group(P<0.05),and the activation rate of the medial femoris muscle at the mid-support stage was significantly greater than that of the FFF intervention group and normal In the arch group(P<0.05),the activation rate of lateral femoral muscle in the later stage of support was greater than that of the FFF intervention group and the normal arch group(P<0.05),and the activation rate of tibial anterior muscle and biceps femoris was significantly greater than that of the normal arch group(P< 0.05),and the activation rate of the medial gastrocnemius,lateral femoris,and biceps femoris was significantly higher than before the experiment(P<0.05).In short,after the experiment,the electromyography parameters of the FFF intervention group were not significantly different from the normal arch group(P>0.05).Conclusion:1.The 16-week of muscle function training of the feet and lower limbs can significantly increase the standard scaphoid height index and foot print ratio index of FFF female college students,and improve the maintenance ability of their arch shape.2.Due to the lack of good arch support and poor buffering ability,FFF female college students show different gait from normal people during walking.16 week foot and lower limb muscle function training can improve the buffering ability of FFF female college students,increase the stability during walking and improve their abnormal gait.3.The 16-week foot and lower extremity muscle function training made the FFF female college students' lower extremity muscle contraction tend to be normal during the support period during the walking process,which may be an important reason for improving their abnormal gait. |
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