Research On The Difference Between Dominant Leg And Non-dominant Leg In The Process Of Striding At Different Speeds

Background: Stepping initiation is one of the most repeatable body movements in the daily life.Coherent and stable walking is made up of many single steps.It is found that the step-by-step movement can be used as a common posture for the dynamic stability of the body.It alternates the left and right legs when walking and the base of support changes alternately.Therefore,the stability of body dynamic posture is a great challenge.When taking a step,the left and right legs play different roles in maintaining the body's dynamic postural stability.The asymmetry of the left and right sides may not cause concern in daily life,but the morbid asymmetry in the clinic has occurred from time to time.This asymmetry of the pathology and the asymmetry between the left and right sides of healthy adults are not the same.Therefore,it is necessary to study the changes in body postural adjustments at different speeds,as well as the difference in the process of walking left and right legs at different speeds,which can help us to further distinguish between the asymmetry caused by pathology in the clinic and the normal physical asymmetry of healthy adults.In addition,it is helpful for the clinical rehabilitation of patients with Parkinson's,hemiplegia and patients with left and right limb disorders for clinical diagnosis and evaluation.Objective: To explore the variation and symmetry of temporal parameters of center of pressure(COP)displacements,center of mass(COM)acceleration between the dominant and non-dominant legs during step initiation at different speeds.Methods: A Kistler three-dimensional force plate,a Noraxon three-dimensional accelerometer and plantar pressure switch were used to collect raw data of eight healthy adults who completed step initiation at normal stepping(NS)and quick stepping(QS).The temporal and spatial parameters of the COP and the COM of the dominant and non-dominant legs were analyzed in the anterio-posterior(AP)and medio-lateral(ML)directions.Results:(1)Under the two experimental conditions,the dominant leg and the non-dominant leg were significantly different in the unbalanced period and the APA period,and the duration of non-dominant leg in imbalance and APAS was significantly longer than that of the dominant leg.(2)There was no significant difference in the percentage of dominant and non-dominant legs in the total length of time between the normal and fast stepping conditions.(3)There was no significant difference in COP displacement between the dominant and non-dominant legs in the ML and AP directions under the normal and fast stepping conditions.(4)In the ML direction,under the two conditions,the maximum COM acceleration of the dominant and non-dominant legs in the APA period and the average value of the COM acceleration during the step were significantly different;when the dominant leg or non-dominant leg started stride separately,the maximum COM acceleration of normal stride and fast stride in unloading phase,the maximum COM acceleration of APAs phase and the COM acceleration of unbalanced phase were significant differences.There were significant differences in the change of speed,the average COM acceleration,the swing period and the average COM acceleration during stride period.(5)In the AP direction,the main effects of "walking leg" and "walking speed" had no significant difference for all parameters of COM acceleration P > 0.05.(6)In the ML direction,the COM speed range of dominant and non-dominant legs in unbalanced period and APAs period had significant difference.There were significant differences in the maximum COM speed in unbalanced period,the variation range of COM speed in unbalanced period and the average COM speed in stride period under the two conditions.(7)In the AP direction,there was no significant difference between the main effects of "walking leg" and "walking speed" on each parameter P value of COM speed > 0.05.(8)In the ML and AP directions,under the two conditions,the peak COP displacement of the non-dominant leg,COM acceleration and COM speed in the APA period were significantly higher than that of the dominant leg.Conclusions:(1)When the healthy adults are in normal steps,the non-dominant leg may achieve the same performance as the dominant leg by prolonging the APAs period(especially in the imbalance period);in the quick-stepping condition,non-dominant legs may maintain better stability by increasing the imbalance period and the length of unloading period in proportion.In the APA and CPAs period,the dominant and the non-dominant legs promote the movement of the COP displacement trajectory;(2)With the acceleration of the gait,the ML direction was asymmetrical for maintaining the stability of body posture,that is to say,it has a lateraityl.The APA period was a significant indicator of the balance of the body posture,and it is asymmetrical during the step initiation.In the ML direction,the dominant leg greatly pushed COM forward and toward the supporting leg,indicating that dominant leg better maintained the body dynamic posture stability;(3)When the gait speed is increased,the CNS initiated a stronger adjustment mechanism to eliminate the instability of the posture.During the swing period,CPAs accelerated as the speed of the step increased,indicating APAs and CPAs co-regulated the stability of posture;(4)under the two condition,the activity of APAs in the dominant leg was significantly higher than that of the non-dominant leg,the amplitude of APAs in the dominant legs was significantly higher than that of non-dominant leg.The dominant leg may help to step forward better,while the non-dominant leg provided a better support.