Biomechanics of Gait Termination and Lower Limb Muscle Activity during Walking in Children with Backpack Load

Objectives:The falling risk and accident incidence of children is directly related to gait termination ability and backpack load.Analysis of the lower limb muscle activity during gait termination in children with backpack load helps to understand the dynamic posture stability and balance mechanism when children with backpack load during gait termination.Methods:The Noraxon surface electromyography system was used,the characteristic parameters were muscle raised starting time,duration,iEMG and maximum amplitude,the load way were empty bag(0% BW) and 15% BW bag,the way of gait termination were planned stop and unplanned stop,to analysis the lower limb muscle activity during gait termination in children with backpack load.Results:The iEMG,maximum amplitude and duration were significantly increased when carrying 15%BW load during unplanned gait termination(P<0.05).The MRO of the leading limb between unplanned and planned gait termination were different:during unplanned gait termination the BF was recruited first,then the TA,the Gas or RF was recruited at last.In contrast during planned gait termination the TA was recruited first,BF secondly and the Gas or RF last.The MRO of the trailing limb between unplanned and planned gait termination showed a similar pattern:the Gas of RF first,then the TA and the BF last.Conclusion:Backpack load and unplanned stop can change lower limb muscle activity of children on gait termination,the reason may be related by the change of biomechanical mode of maintain body posture stability which caused by backpack load and unplanned stop.