Research On Fall Risk Of Walking In The Elderly Based On Gait Variability

‘Healthy aging' has become an urgent goal for individuals,families and society under the background of the intensified population aging trend in China.Physical activity is an important way to promote ‘healthy aging.' Walking is the most important form of physical activity and a generally accepted form of exercise for community dwelling elderly people.Walking has many health benefits,but there is also a potential fall risk.Given the high incidence and serious consequences of falls in the elderly,assessing and reducing the fall risk of walking is a prerequisite and guarantee for achieving the health benefits of walking.Gait variability is used to reflect the dispersion of gait parameters in continuous walking,usually include standard deviation or coefficient of variability.For community dwelling elderly people with independent walking ability,the gait variability index can reflect the fall risk more sensitively than the conventional gait parameter index.However,the most of research focuses on the temporal spatial parameter variability so that the research is difficult to fully reflect the gait variability characteristics of the elderly and omits some gait variability related to the fall risk.The integrated indicators covering the comprehensive gait variability information may help to improve the evaluation validity of the fall risk.At the same time,the relationship between the gait variability indexes and the possible mechanisms of different indexes need to be further investigated.Therefore,this study firstly compares the gait variability of the elderly and young people in five categories of gait parameter,and screens out the gait variability indicators that reflect the characteristics of the elderly;Secondly,the relationship between the selected variability indicators is explored by principal component factor analysis.Trying to reveal the possible mechanisms,pathways and influencing factors of different types of variability,and construct a comprehensive index of gait variability,including three factor scores and comprehensive scores;again,through the correlation analysis of gait variability comprehensive index and balance ability in order to verify the validity of the gait variability index on the assessment of fall risk and clarify whether the classic balance ability test can reflect the fall risk associated with gait variability;finally,evaluation fall risk of the elderly with different walking ratios(step / cadence).The aim is to reveal the characteristic of the elderly‘s gait variability,extend the generation and control theory of gait variability,enrich the fall risk assessment method,provide a reference for exploring mechanism of gait variability,in order to provide reference for assessment of gait variability and fall risk of the elderly,and provide a low-fall risk walking advice to reduce the fall rate and ensure the health benefits of walking and help “healthy ageing”.Conclusion as below:1)Through comparison of 29 gait variability indicators of gait parameters in the elderly and young people,it is found that the elderly's 7 indexes are significantly higher than the young ones,indexes include stride variability,step width variability,stride time variability,double stance phase variability,load response phase variability,COP lateral symmetry variability and time change heel to forefoot variability,which can be used as gait variability characteristics of the elderly.2)Principal component factor analysis of the above 7 variability indexes initially found that the asynchronous variability may have different generation and control mechanisms,pathways and main influencing factors: the non-feedback path that primarily relying on the central walking procedure instructions,scarcely relying on peripheral sensory information is related to double stance phase and load response phase variability(factor 1);the weak-feedback path that less relying on peripheral sensory information is related to stride time and step width variability(factor 2);the strong-feedback path that primarily relying on peripheral sensory information is related to stride,COP lateral symmetry and time change heel to forefoot variability,(factor 3).3)The comprehensive index of gait variability has a medium correlation with the static balance ability.The factor 3,including stride,COP lateral symmetry and time change heel to forefoot variability can affect the static balance ability to some extent.On the one hand,it shows that the comprehensive index of gait variability has certain validity for evaluation of balance ability and fall risk;on the other hand,it shows that the classical static balance ability is difficult to reflect the fall risk associated with gait variability,especially for gait variability indexes in factor 1 and factor 2.It is suggested that the comprehensive indicator of gait variability should be used as a necessary supplement to the assessment of fall risk.4)The comprehensive index of gait variability can identify the difference in walking dynamic balance ability between the elderly,and it is expected to be an indicator of fall risk in the elderly.Based on the evaluation results,the walking dynamic balance will not be affected with the increase of step and/or cadence in the elderly with walking ratio higher than 0.5.An appropriate increase in step should contribute to improvement of gait variability and stability in the elderly with walking ratio lower than 0.5.