TheseBootsWereMadeforWalkin’

TheBiomechanicsofWalkinginaFractureBoot

Darlina Liu April21st,2016 BIOL438

FractureBoot=WalkerBoot=CAMWalker

AdjustableInflation Non-inflated RangeofMotion(ROM)

Treatmentfor…• AnkleSprain• StressFracture• DiabeticUlcers• Tendonitis• PlantarFasciitis• Andmore…

WhyStudyThis?• Youwillwalkabout75,000milesinyourlifetime

WhyStudyThis?•Peoplehaveinjuredthemselveswhilewearingaboot

Question

•Howdoeswalkinginafracturebootdifferfromnormalwalking?• Isthefracturebooteffectiveincontrollinganklemotion?•Whataretheeffectsonthesupportingfoot?•Whatarethedifferencesinenergy?

Walking

Walking:StancePhase

AnkleMovement

BonesandMusclesInvolved

Hypothesis

•Predictdecreasedanklerotationforbootfootandincreasedanklerotationforsupportingfootcomparedtonormalwalking

•Predictthatwalkinginfracturebootwillrequiregreaterenergyexpenditurecomparedtonormalwalking

Methods• Filming:SonyCybershot RX10II• DataAnalysis:LoggerProandExcel

MediumLiteVectraWalkerBootfromBregg

ResultsofVideoAnalysis

•AnkleAngle

•StrideLength•KineticEnergy•Velocity

•PotentialEnergy

Video:WalkinginFractureBoot

Video:NormalWalking

AnkleAngleCalculation

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AnkleAn

gle(degrees)

Time(s)

LeftFootAnkleAngle:Bootvs.Normal

Boot Normal

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AnkleAn

gle(degrees)

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LeftFootAnkleAngle:Bootvs.Normal

Boot Normal

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AnkleAn

gle(degrees)

Time(s)

RightFootAnkleAngle:Bootvs.Normal

Boot Normal

Boot Normal

AVERAGE(degrees) Left* Right Left Right

MinAnkleAngle 81.1 91.1 78.1 88.2

MaxDorsiflexion 8.9 N/A 11.9 1.8

MaxAnkleAngle 97.6 120.6 107.4 113.0

MaxPlantarflexion 7.6 30.6 17.4 23.0

RangeofMotion 16.5 29.5 29.3 24.8

AnkleComparison

StrideLength•distancecoveredbyinitialcontactofonefootandconsecutivecontactofsamefoot•2MPH=0.894m/s

Boot Normal#ofSteps 6 6

Timeelapsed (s) 4 5Total distancetravelled(m) 3.58 4.47Stridelength (m/step) 0.596 0.745

KineticEnergy=½mv2

• WeightofBoot=1.2lbs =0.54kg• WeightofSneaker=0.4lbs =0.18kg

Boot: Left Normal:Left

Boot:Right Normal:Right

KineticEnergy(J)

1.053 0.325 0.248 0.208

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Kine

ticEne

rgy(J)

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KineticEnergyComparisonbetweenBootLegandNormalLeg(Left)

Boot Normal

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Kine

ticEne

rgy(J)

Time(s)

KineticEnergyComparionbetweenSupportingLegandNormalLeg(Right)

Boot Normal

PotentialEnergy=mgh• WeightofBoot=1.2lbs =0.54kg• WeightofSneaker=0.4lbs =0.18kg• g=9.81m/s2

Boot(Left) Normal(Left)

MaximumHeight(m) 0.233 0.324

PotentialEnergy(J) 1.243 0.577

Conclusions& Implications

• Fracturebootdoesstabilizeanklemotionbutitisnotperfect• Thesupportingfootdoesplayacompensatoryrole• Walkinginafracturebootrequiresmoreenergyexpenditure

➤ Rethinkouruseanddesignoffractureboots

Limitations

•Noinjuryattimeoffilming• Limitednumberoftrials• Two-dimensionalvideoanalysis• Treadmilldifferentfromnaturalwalking

NextSteps

•Camerafrommultipleangles•Forcepads•Varyspeedandduration•Examineprotonationoffoot•Analyzewalkinginothertypesofboots

References• TheFrequencyofInjury,MechanismofInjury,andEpidemiologyofAnkleSprains(Garrick1977)• Walking,FootPain,andBiomechanics(http://footactive.co.uk/blog/255-walking-foot-pain-and-biomechanics)• BiomechanicsofFootStrikes&ApplicationsToRunningBarefootorinMinimalFootwear(http://www.barefootrunning.fas.harvard.edu/4BiomechanicsofFootStrike.html)• TheInfluenceofKneePositiononAnkleDorsiflexion(Baumbach etal2014)• Step&StrideLength(http://www.clinicalgaitanalysis.com/teach-in/step/)• WalkingandRunningonTreadmill:TheStandardCriteriaforKinematicStudies(Padulo etal2014)

Thankyou!Anyquestions?