Author's Accepted Manuscript
The effect of stride length on the dynamics of barefoot and shod running M.A. Thompson, A. Gutmann, J. Seegmiller, C.P. McGowan
www.elsevier.com/locate/jbiomech
PII: DOI: Reference:
S0021-9290(14)00270-X http://dx.doi.org/10.1016/j.jbiomech.2014.04.043 BM6644
To appear in:
Journal of Biomechanics
Accepted date: 28 April 2014 Cite this article as: M.A. Thompson, A. Gutmann, J. Seegmiller, C.P. McGowan, The effect of stride length on the dynamics of barefoot and shod running, Journal of Biomechanics, http://dx.doi.org/10.1016/j.jbiomech.2014.04.043 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Manuscript#:BMD1301052 Revision2 THEEFFECTOFSTRIDELENGTHONTHEDYNAMICSOFBAREFOOTANDSHODRUNNING M.A.Thompson1,A.Gutmann2,J.Seegmiller3,4,C.P.McGowan1,2,4 1 NeuroscienceProgram UniversityofIdaho Moscow,ID84844 2 DepartmentofBiologicalSciences UniversityofIdaho Moscow,ID84844 3 DepartmentofMovementSciences UniversityofIdaho Moscow,ID84844 4 WWAMIMedicalEducationProgram UniversityofIdaho Moscow,ID84844 Runninghead:stridelengthbarefootandshodrunningdynamics Keywords:biomechanics,running,barefoot,stridelength Currentaddressforcorrespondence: MelissaThompson 138WhalenGym ExerciseScienceDepartment FortLewisCollege 1000RimDrive Durango,CO81301 [email protected] (ph:9702477580)
1
ABSTRACT Anumberofinterventionsandtechniquechangeshavebeenproposedtoattempttoimprove performance and reduce the number of running related injuries. Running shoes, barefoot runningandalterationsinspatiotemporalparameters(stridefrequency&stridelength)have beenassociatedwithsignificantkinematicandkineticchanges,whichmayhaveimplicationsfor performance and injury prevention. However, because footwear interventions have been shown to also affect spatiotemporal parameters, there is uncertainty regarding the origin of thekinematicandkineticalterations.Therefore,thepurposeofthisstudywastoindependently evaluatetheeffectsofshoesandchangesinstridelengthonlowerextremitykinetics.Eleven individuals ran overground at stride lengths ± 5 and 10% of their preferred stride length, in boththebarefootandshodcondition.Threedimensionalmotioncaptureandforceplatedata werecapturedsynchronouslyandusedtocomputelowerextremityjointmoments.Wefounda significant main effect of stride length on anteriorposterior and vertical GRFs, and sagittal plane knee and ankle moments in both barefoot and shod running. When subjects ran at identicalstridelengthsinthebarefootandshodconditionswedidnotobservedifferencesfor anyofthekineticvariablesthatweremeasured.Thesefindingssuggestthatbarefootrunning triggersadecreaseinstridelength,whichcouldleadtoadecreaseinGRFsandsagittalplane jointmoments.Whenevaluatingbarefootrunningasapotentialoptiontoreduceinjury,itis importanttoconsidertheassociatedchangeinstridelength. INTRODUCTION Giventhepopularityofrunning,anumberofinterventionsandtechniquechangeshavebeen 2
proposed to attempt to improve performance and reduce the number of running related injuries. Altering running conditions can lead to kinematic and kinetic changes that may optimize muscle/tendon function and/or reduce stress on biological tissues (e.g. tendon, ligament, cartilage). Running shoes, barefoot running and alterations in spatiotemporal parameters(stridefrequency&stridelength)(Derrick,etal.,1998;Heiderscheit,etal.,2011; Hobara, et al., 2011; Lafortune, et al., 1996; White & Lage, 1993) have been associated with significantkinematicandkineticchanges,whichmayhaveimplicationsperformanceandinjury risk.However,someinterventions,suchasfootwear,havebeenshowntoalsoaffectspatio temporal parameters, which leads to uncertainty regarding the origin of the kinematic and kinetic alterations. Therefore, the aim of this study was to systematically manipulate shoe conditions (barefoot vs. shod) and stride length in order to understand how these conditions independentlyaffectrunningdynamics. Several previous studies have evaluated kinetic differences between barefoot and shod running,yetthereisnoconsensusonpotentialdifferencesingroundreactionforces(GRFs).For example,Divertetal.(2005),Liebermanetal.(2010)andSquadrone&Gallozzi(2009)report decreasedimpactforcesinthebarefootcondition,whereasDeWitetal.(2000)andDickinson etal.(1985)foundnodifferenceinimpactpeaksbetweenthebarefootandshodrunning,and Komi et al. (1987) found greater impact peaks in the barefoot condition. Varied results have also been reported for the differences in the GRF active peak between barefoot and shod running.Braunsteinetal.(2010),Divertetal.(2005)andKerriganetal.(2009)reportgreater activepeaksintheshodcondition,whileDeWitetal.(2000)andSquadrone&Gallozzi(2009) 3
found no difference in the GRF active peak between barefoot and shod running. Potential differencesintheanteriorposteriorGRFcomponentsarealsounclear;withDivertetal.(2005) reportinggreaterpropulsiveforcesinthebarefootconditionandDeWitetal.(2000)finding nodifferenceineitherbrakingorpropulsiveforcebetweenconditions. OnepossiblereasonforthediscrepancyinGRFsbetweenbarefootandshodrunningmaybe differences in kinematic alterations when individuals run barefoot. While shoes offer an obvious protective benefit, the elevated and cushioned heel of modern running shoes leads many individuals to adopt a rearfoot strike pattern, which may increase collision forces (Lieberman,etal.,2010)andjointmoments(Kerrigan,etal.,2009).Alternatively,whenrunning barefoot, individuals tend to have a decreased range of motion at the knee, ankle and hip (Jenkins&Cauthon,2011);amoreplantarflexedpositionatgroundcontact(Divert,etal.,2005; Lieberman,etal.,2010;Squadrone&Gallozzi,2009);andasignificantlyshorterstridelengthas comparedtotheshodcondition(DeWit,etal.,2000;Divert,etal.,2005;Kerrigan,etal.,2009; Komi,etal.,1987;Lieberman,etal.,2010;Squadrone&Gallozzi,2009).Thechangeinstride lengthisofparticularinterestasithasbothkinematicandkineticimplications. Whiledifferencesinrunningkineticsassociatedwithbarefootandshodrunninghavereceived considerable attention, the independent changes associated with running in shoes (versus barefoot) and stride length have not be evaluated. In a study of shod runners, Farley & Gonzalez(1996)haveshownthatpeakverticalGRFsdecreasedsignificantlywithdecreasesin stride length. Derrick et al. (1998) report that decreasing stride length in the shod condition 4
resulted in decreased lower extremity joint moments, though no statistics are provided. Further,Kerriganetal.(2009)foundthatpeaklowerextremityjointmomentswerereducedin barefoot running, but there was little correlation between the decreased stride length associatedwiththebarefootconditionandthedecreasedjointmoments.Whilestudieshave clearlyshownthatbarefootrunningresultsinreducedstridelengthsrelativetoshodrunning,it remains unclear how these changes influence joint dynamics. Therefore, in this study we independentlyevaluatedtheeffectsofshoesandchangesinstridelengthonlowerextremity kinetics.Wehypothesizedthatpeakgroundreactionforcesandjointmomentswouldnotdiffer for conditions of similar stride length and running velocity, regardless if an individual was runninginshoes. METHODS: Elevenhealthy,physicallyactiveadults[6menand5women,age:29±5.6yr;height:1.63± 0.12 m; mass: 62.6 ± 12.1 kg] participated in this study. Subjects were required to perform a minimum of 30 minutes of physical activity at least 5 days a week, and be free of musculoskeletalinjuryofthelowerextremitiesorback.TheUniversityofIdaho’sInstitutional ReviewBoardapprovedtheprotocolforthisstudy,andwritteninformedconsentwasobtained fromeachsubject. ExperimentalProtocol Subjects completed 2 testing sessions, which were separated by a minimum of 24 hours. Subjects began each session with 510 minutes of easy running in order to warmup and 5
habituatetotherunway.Session1wasusedtodeterminethesubject’spreferredrunninggait (i.e.,selfselectedstridelengthandrunningvelocity)inbothbarefootandshodconditions.For the baseline (preferred) conditions, stride length and running velocity were averaged from 5 trials.InSession2,subjectsranwiththeirstridelengthmanipulatedto±5and10%oftheir preferredshodstridelengthwhilebarefootandshod,foratotalof8conditions.Bothbarefoot and shod stride length manipulations were based on the preferred shod condition so that in subsequent trials (e.g. +10%) the stride length was identical in both the barefoot and shod conditions. This allowed the effects of stride length and the shod/barefoot conditions to be independently evaluated. Additionally, all conditions in Session 2 were completed at the subject’s preferred shod running velocity. In order to control running velocity, subjects matched their speed to a target on a motor driven pulley system that ran parallel to the runway. Stride length was controlled by having subjects match step length to strips of tape placed along the runway (Fig. 1). In Session 2, subjects performed 10 trials of each condition and 5 trials that were within 2% of the desired stride length and 5% of the desired running velocitywereusedforanalysis. Kinetics 3dimensionalmotionanalysisandGRFdatawerecapturedassubjectsranovera15mrunway withaforceplate(AMTI,Waterton,MA)embeddedat10m.16retroreflectivemarkerswere affixed with doublesided tape to specific landmarks according to the Modified Helen Hayes Marker set (Kadaba, et al., 1990). Markers were placed on the right and left anterior and posteriorsuperioriliacspines,lateralmidthigh,lateralfemoralepicondyle,lateralmidshank, 6
lateralmalleolus,secondmetatarsalheadandcalcaneus.Fortheshodcondition,heelandtoe markerswereplacedontheshoesatthepositionsbestaligningwiththeanatomicallandmarks. Height,weight,leglength,andwidthsoftheanklesandkneesweremeasuredforappropriate anthropometricscaling.3dimensionalpositionsofeachmarkerwerecapturedat250Hzviaa ViconMXmotionanalysissystem(Vicon,OxfordMetricsLtd.,UK).Markertrajectorydatawere filteredusingaWoltringfilteringroutinewithapredictedmeansquareerrorvalueof4mm2. The three orthogonal components of the GRF data were recorded at 1000 Hz from the force plateinsynchronywiththemotioncapturedata.Forceplatedatawerelowpassfilteredat30 HzusingasecondorderButterworthfilterbeforebeingdownsampledandcombinedwiththe motioncapturedata. Stridelengthwasmeasuredasthehorizontaldistancebetweenipsilateralheelmarkerminima. Running velocity wascalculated as the horizontal displacement of each anterior superior iliac spine (ASIS) marker through the capture volume divided by the corresponding time. Running velocitywascalculatedforboththerightandleftASISmarkersandaveraged.Jointmoments werecalculatedforeachtrialviaaninversedynamicsmodelimplementedinViconPlugInGait. Statistics Statisticaldifferencesinpeakkineticparametersweredeterminedusingarepeatedmeasures General Linear Model in SPSS (IBM, Armonk, NY). When a significant effect was identified, a posthocBonferronipairwisecomparisonwasperformedtodeterminewhichconditionswere significantlydifferent.StatisticalsignificancewasdefinedasP
The effect of stride length on the dynamics of barefoot and shod running M.A. Thompson, A. Gutmann, J. Seegmiller, C.P. McGowan
www.elsevier.com/locate/jbiomech
PII: DOI: Reference:
S0021-9290(14)00270-X http://dx.doi.org/10.1016/j.jbiomech.2014.04.043 BM6644
To appear in:
Journal of Biomechanics
Accepted date: 28 April 2014 Cite this article as: M.A. Thompson, A. Gutmann, J. Seegmiller, C.P. McGowan, The effect of stride length on the dynamics of barefoot and shod running, Journal of Biomechanics, http://dx.doi.org/10.1016/j.jbiomech.2014.04.043 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Manuscript#:BMD1301052 Revision2 THEEFFECTOFSTRIDELENGTHONTHEDYNAMICSOFBAREFOOTANDSHODRUNNING M.A.Thompson1,A.Gutmann2,J.Seegmiller3,4,C.P.McGowan1,2,4 1 NeuroscienceProgram UniversityofIdaho Moscow,ID84844 2 DepartmentofBiologicalSciences UniversityofIdaho Moscow,ID84844 3 DepartmentofMovementSciences UniversityofIdaho Moscow,ID84844 4 WWAMIMedicalEducationProgram UniversityofIdaho Moscow,ID84844 Runninghead:stridelengthbarefootandshodrunningdynamics Keywords:biomechanics,running,barefoot,stridelength Currentaddressforcorrespondence: MelissaThompson 138WhalenGym ExerciseScienceDepartment FortLewisCollege 1000RimDrive Durango,CO81301 [email protected] (ph:9702477580)
1
ABSTRACT Anumberofinterventionsandtechniquechangeshavebeenproposedtoattempttoimprove performance and reduce the number of running related injuries. Running shoes, barefoot runningandalterationsinspatiotemporalparameters(stridefrequency&stridelength)have beenassociatedwithsignificantkinematicandkineticchanges,whichmayhaveimplicationsfor performance and injury prevention. However, because footwear interventions have been shown to also affect spatiotemporal parameters, there is uncertainty regarding the origin of thekinematicandkineticalterations.Therefore,thepurposeofthisstudywastoindependently evaluatetheeffectsofshoesandchangesinstridelengthonlowerextremitykinetics.Eleven individuals ran overground at stride lengths ± 5 and 10% of their preferred stride length, in boththebarefootandshodcondition.Threedimensionalmotioncaptureandforceplatedata werecapturedsynchronouslyandusedtocomputelowerextremityjointmoments.Wefounda significant main effect of stride length on anteriorposterior and vertical GRFs, and sagittal plane knee and ankle moments in both barefoot and shod running. When subjects ran at identicalstridelengthsinthebarefootandshodconditionswedidnotobservedifferencesfor anyofthekineticvariablesthatweremeasured.Thesefindingssuggestthatbarefootrunning triggersadecreaseinstridelength,whichcouldleadtoadecreaseinGRFsandsagittalplane jointmoments.Whenevaluatingbarefootrunningasapotentialoptiontoreduceinjury,itis importanttoconsidertheassociatedchangeinstridelength. INTRODUCTION Giventhepopularityofrunning,anumberofinterventionsandtechniquechangeshavebeen 2
proposed to attempt to improve performance and reduce the number of running related injuries. Altering running conditions can lead to kinematic and kinetic changes that may optimize muscle/tendon function and/or reduce stress on biological tissues (e.g. tendon, ligament, cartilage). Running shoes, barefoot running and alterations in spatiotemporal parameters(stridefrequency&stridelength)(Derrick,etal.,1998;Heiderscheit,etal.,2011; Hobara, et al., 2011; Lafortune, et al., 1996; White & Lage, 1993) have been associated with significantkinematicandkineticchanges,whichmayhaveimplicationsperformanceandinjury risk.However,someinterventions,suchasfootwear,havebeenshowntoalsoaffectspatio temporal parameters, which leads to uncertainty regarding the origin of the kinematic and kinetic alterations. Therefore, the aim of this study was to systematically manipulate shoe conditions (barefoot vs. shod) and stride length in order to understand how these conditions independentlyaffectrunningdynamics. Several previous studies have evaluated kinetic differences between barefoot and shod running,yetthereisnoconsensusonpotentialdifferencesingroundreactionforces(GRFs).For example,Divertetal.(2005),Liebermanetal.(2010)andSquadrone&Gallozzi(2009)report decreasedimpactforcesinthebarefootcondition,whereasDeWitetal.(2000)andDickinson etal.(1985)foundnodifferenceinimpactpeaksbetweenthebarefootandshodrunning,and Komi et al. (1987) found greater impact peaks in the barefoot condition. Varied results have also been reported for the differences in the GRF active peak between barefoot and shod running.Braunsteinetal.(2010),Divertetal.(2005)andKerriganetal.(2009)reportgreater activepeaksintheshodcondition,whileDeWitetal.(2000)andSquadrone&Gallozzi(2009) 3
found no difference in the GRF active peak between barefoot and shod running. Potential differencesintheanteriorposteriorGRFcomponentsarealsounclear;withDivertetal.(2005) reportinggreaterpropulsiveforcesinthebarefootconditionandDeWitetal.(2000)finding nodifferenceineitherbrakingorpropulsiveforcebetweenconditions. OnepossiblereasonforthediscrepancyinGRFsbetweenbarefootandshodrunningmaybe differences in kinematic alterations when individuals run barefoot. While shoes offer an obvious protective benefit, the elevated and cushioned heel of modern running shoes leads many individuals to adopt a rearfoot strike pattern, which may increase collision forces (Lieberman,etal.,2010)andjointmoments(Kerrigan,etal.,2009).Alternatively,whenrunning barefoot, individuals tend to have a decreased range of motion at the knee, ankle and hip (Jenkins&Cauthon,2011);amoreplantarflexedpositionatgroundcontact(Divert,etal.,2005; Lieberman,etal.,2010;Squadrone&Gallozzi,2009);andasignificantlyshorterstridelengthas comparedtotheshodcondition(DeWit,etal.,2000;Divert,etal.,2005;Kerrigan,etal.,2009; Komi,etal.,1987;Lieberman,etal.,2010;Squadrone&Gallozzi,2009).Thechangeinstride lengthisofparticularinterestasithasbothkinematicandkineticimplications. Whiledifferencesinrunningkineticsassociatedwithbarefootandshodrunninghavereceived considerable attention, the independent changes associated with running in shoes (versus barefoot) and stride length have not be evaluated. In a study of shod runners, Farley & Gonzalez(1996)haveshownthatpeakverticalGRFsdecreasedsignificantlywithdecreasesin stride length. Derrick et al. (1998) report that decreasing stride length in the shod condition 4
resulted in decreased lower extremity joint moments, though no statistics are provided. Further,Kerriganetal.(2009)foundthatpeaklowerextremityjointmomentswerereducedin barefoot running, but there was little correlation between the decreased stride length associatedwiththebarefootconditionandthedecreasedjointmoments.Whilestudieshave clearlyshownthatbarefootrunningresultsinreducedstridelengthsrelativetoshodrunning,it remains unclear how these changes influence joint dynamics. Therefore, in this study we independentlyevaluatedtheeffectsofshoesandchangesinstridelengthonlowerextremity kinetics.Wehypothesizedthatpeakgroundreactionforcesandjointmomentswouldnotdiffer for conditions of similar stride length and running velocity, regardless if an individual was runninginshoes. METHODS: Elevenhealthy,physicallyactiveadults[6menand5women,age:29±5.6yr;height:1.63± 0.12 m; mass: 62.6 ± 12.1 kg] participated in this study. Subjects were required to perform a minimum of 30 minutes of physical activity at least 5 days a week, and be free of musculoskeletalinjuryofthelowerextremitiesorback.TheUniversityofIdaho’sInstitutional ReviewBoardapprovedtheprotocolforthisstudy,andwritteninformedconsentwasobtained fromeachsubject. ExperimentalProtocol Subjects completed 2 testing sessions, which were separated by a minimum of 24 hours. Subjects began each session with 510 minutes of easy running in order to warmup and 5
habituatetotherunway.Session1wasusedtodeterminethesubject’spreferredrunninggait (i.e.,selfselectedstridelengthandrunningvelocity)inbothbarefootandshodconditions.For the baseline (preferred) conditions, stride length and running velocity were averaged from 5 trials.InSession2,subjectsranwiththeirstridelengthmanipulatedto±5and10%oftheir preferredshodstridelengthwhilebarefootandshod,foratotalof8conditions.Bothbarefoot and shod stride length manipulations were based on the preferred shod condition so that in subsequent trials (e.g. +10%) the stride length was identical in both the barefoot and shod conditions. This allowed the effects of stride length and the shod/barefoot conditions to be independently evaluated. Additionally, all conditions in Session 2 were completed at the subject’s preferred shod running velocity. In order to control running velocity, subjects matched their speed to a target on a motor driven pulley system that ran parallel to the runway. Stride length was controlled by having subjects match step length to strips of tape placed along the runway (Fig. 1). In Session 2, subjects performed 10 trials of each condition and 5 trials that were within 2% of the desired stride length and 5% of the desired running velocitywereusedforanalysis. Kinetics 3dimensionalmotionanalysisandGRFdatawerecapturedassubjectsranovera15mrunway withaforceplate(AMTI,Waterton,MA)embeddedat10m.16retroreflectivemarkerswere affixed with doublesided tape to specific landmarks according to the Modified Helen Hayes Marker set (Kadaba, et al., 1990). Markers were placed on the right and left anterior and posteriorsuperioriliacspines,lateralmidthigh,lateralfemoralepicondyle,lateralmidshank, 6
lateralmalleolus,secondmetatarsalheadandcalcaneus.Fortheshodcondition,heelandtoe markerswereplacedontheshoesatthepositionsbestaligningwiththeanatomicallandmarks. Height,weight,leglength,andwidthsoftheanklesandkneesweremeasuredforappropriate anthropometricscaling.3dimensionalpositionsofeachmarkerwerecapturedat250Hzviaa ViconMXmotionanalysissystem(Vicon,OxfordMetricsLtd.,UK).Markertrajectorydatawere filteredusingaWoltringfilteringroutinewithapredictedmeansquareerrorvalueof4mm2. The three orthogonal components of the GRF data were recorded at 1000 Hz from the force plateinsynchronywiththemotioncapturedata.Forceplatedatawerelowpassfilteredat30 HzusingasecondorderButterworthfilterbeforebeingdownsampledandcombinedwiththe motioncapturedata. Stridelengthwasmeasuredasthehorizontaldistancebetweenipsilateralheelmarkerminima. Running velocity wascalculated as the horizontal displacement of each anterior superior iliac spine (ASIS) marker through the capture volume divided by the corresponding time. Running velocitywascalculatedforboththerightandleftASISmarkersandaveraged.Jointmoments werecalculatedforeachtrialviaaninversedynamicsmodelimplementedinViconPlugInGait. Statistics Statisticaldifferencesinpeakkineticparametersweredeterminedusingarepeatedmeasures General Linear Model in SPSS (IBM, Armonk, NY). When a significant effect was identified, a posthocBonferronipairwisecomparisonwasperformedtodeterminewhichconditionswere significantlydifferent.StatisticalsignificancewasdefinedasP
