Background:Segment coordination variability (CV) is a movement pattern associated with running-related injuries.It can also be adversely affected by a prolonged run.However,research on this topic is currently limited.The purpose of this study was to investigate the effects of a pro-longed run on segment CV and vertical loading rates during a treadmill half marathon.Methods:Fifteen healthy runners ran a half marathon on an instrumental treadmill in a biomechanical laboratory.Synchronized kinematic and kinetic data were collected every 2 km (from 2 km until 20 km),and the data were processed by musculoskeletal modeling.Segment CVs were computed from the angle-angle plots of selected pelvis-thigh,thigh-shank,and shank-rearfoot couplings using a modified vector coding tech-nique.The loading rate of vertical ground reaction force was also calculated.A one-way MANOVA with repeated measures was performed on each of the outcome variables to examine the main effect of running mileage.Results:Significant effects of running mileage were found on segment CVs (p ＜ 0.010) but not on loading rate (p =0.881).Notably,during the early stance phase,the CV of pelvis frontal vs.thigh frontal was significantly increased at 20 km compared with the CV at 8 km (g=0.59,p 0.022).The CV of shank transverse vs.rearfoot frontal decreased from 2 km to 8 km (g 0.30,p 0.020) but then significantly increased at both 18 km (g =0.05,p ＜ 0.001) and 20 km (g =0.36,p ＜ 0.001).Conclusion:At the early stance,runners maintained stable CVs on the sagittal plane,which could explain the unchanged loading rate throughout the half marathon.However,increased CVs on the frontal/transverse plane may be an early sign of fatigue and indicative of possible injury risk.Further studies are necessary for conclusive statements in this regard.

Tony Lin-Wei Chen;Duo Wai-Chi Wong;Yan Wang;Qitao Tan;Wing-Kai Lam;Ming Zhang

Department of Biomedical Engineering,Faculty of Engineering,Hong Kong Polytechnic University,Hong Kong SAR 999077,China;Li Ning Sports Science Research Center,Li Ning (China) Sports Goods Co.Ltd,Beijing 101111,China;Hong Kong Polytechnic University Shenzhen Research Institute,Shenzhen 518057,China;Department of Kinesiology,Shenyang Sports Institute,Shenyang 110102,China

运动与健康科学（英文）

[1]Tony Lin-Wei Chen;Duo Wai-Chi Wong;Yan Wang;Qitao Tan;Wing-Kai Lam;Ming Zhang-.Changes in segment coordination variability and the impacts of the lower limb across running mileages in half marathons:Implications for running injuries)[J].运动与健康科学（英文）,2022(01):67-74

mileages,marathons,marathon,rearfoot

Changes,segment,coordination,variability,impacts,lower,limb,across,running,half,Implications,injuries,Background,Segment,movement,pattern,associated,related,It,also,be,adversely,affected,by,prolonged,However,research,this,topic,currently,limited,purpose,study,was,investigate,effects,vertical,loading,rates,during,treadmill,Methods,Fifteen,healthy,runners,instrumental,biomechanical,laboratory,Synchronized,kinematic,kinetic,data,were,collected,every,from,until,processed,musculoskeletal,modeling,CVs,computed,angle,plots,selected,pelvis,thigh,shank,couplings,using,modified,vector,coding,tech,nique,reaction,force,calculated,one,way,MANOVA,repeated,measures,performed,each,outcome,variables,examine,Results,Significant,found,but,not,Notably,early,stance,phase,frontal,significantly,increased,compared,transverse,decreased,then,both,Conclusion,At,maintained,stable,sagittal,plane,which,could,explain,unchanged,throughout,may,fatigue,indicative,possible,injury,risk,Further,studies,necessary,conclusive,statements,regard

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