2Biomechanics of Gait Walking ApplicationsWalking as a Critical Fundamental Movement PatternWalking as a Recreational ActivityWalking as a Modality for RehabilitationWalking as a Competitive SportInfluence of Injury/Disease/Disability on WalkingAging Effects on Walking and Implications IndependenceFootwear IssuesEnergy CostE. Muybridge
3Describing the Gait Cycle Biomechanics of Gait WalkingDescribing the Gait CycleCharacteristics of WalkingCyclicUniversal PatternBi-laterally symmetricRange of SpeedsAdaptable to Varied SurfacesEfficient
4Describing the Gait Cycle Biomechanics of Gait WalkingDescribing the Gait CyclePhases of the Gait CycleStance PhaseInitial Double Limb SupportSingle Limb SupportTerminal Double Limb SupportSwing PhaseInitial SwingTerminal Swing
5Biomechanics of Gait Walking When we walk, what must happen ??Control Forces Produce Resist Dissipate
6Biomechanics of Gait Walking ObjectivesControl ForcesMaintain Balance
7Biomechanics of Gait Walking ObjectivesResist/Dissipate ForcesMaintain BalanceMove Body in Intended Direction
8Biomechanics of Gait Walking ObjectivesResist/Dissipate ForcesMaintain BalanceMove Body in Intended DirectionConserve Energy
9Biomechanics of Gait Walking Produce/Resist /Dissipate Force Source of ForcesGravity Muscle Contraction InertiaDirection of ForcesVertical Fore/Aft Medial LateralMagnitude of Forces.1 to 1.2 BW’s
10Biomechanics of Gait Walking Produce/Resist /Dissipate Force Forces produce moments (torques) that….Cause rotations –Total Body Joint Segment
11Biomechanics of Gait Walking Maintain BalanceWalking……..a series of catastrophes narrowly averted……The Issues –Dynamic MovementInfluenced by external factorsSingle versus Double SupportDepends on Multiple SystemsAdaptations in Base of Support
12Biomechanics of Gait Walking Move Body in Intended DirectionRe-Positioning of Center of GravityRe-Positioning of Limb SegmentsForce Production applied to the ground
13Biomechanics of Gait Walking Conserve EnergyThe Six Determinants of Gait (Inman, et. al.)
14Biomechanics of Gait Walking The Six Determinants of GaitUnderlying ConceptEnergy Expenditure = Work DoneWork = Force x DistanceForce = Mass x AccelerationTherefore – the amount of energy we expend is directly related to the amount of mass we move and the extent and speed of movement
15Biomechanics of Gait Walking Determinants of GaitPelvic Rotation – transverse planeLateral Pelvic Tilt – frontal planeKnee Flexion – during stanceAnkle PF - at Toe OffAnkle DF – at Foot strikeGait Width – frontal plane
16Biomechanics of Gait Walking Role of Foot MotionObjectivesTo aid in force dissipationTo provide a mobile adapterTo provide a rigid lever for propulsionMechanism - Sub-talar Joint MotionA Tri-planar motion PF and DF Inversion/Eversion AB/ADduction
17Biomechanics of Gait Walking At Ground ContactLateral SideMedial SideContact Made on the Lateral Border of the HeelFoot is SupinatedFoot is Rigid
18Biomechanics of Gait Walking Early Stance to MidStanceLateral SideMedial SideFoot is PronatedFoot is Mobile (flexible)Enhances Balance
19Biomechanics of Gait Walking Late Stance to Toe-OffLateral SideMedial SideFoot is SupinatedFoot is RigidEnhances Propulsion
20Biomechanics of Gait Walking Pronation/Supination Issues:Too Little – Loss of force dissipation Loss of Mobility – Balance Stress InjuryToo Much Relationship to Tibial Rotation Associated Patellar Tracking Issues Soft-Tissue StressControl of Pronation/Supination Shoe Design Orthotics Muscle Strengthening – Posterior Tib
22Biomechanics of Gait Running As a component of competitive sportAs a recreational activityAs a stage of motor developmentAs a cause of injury
23Biomechanics of Gait Running Differences between walking and runningVelocity - Greater range than walkingKinematic Parameters - Increase in mostKinetic Parameters - Increase in someEnergy Cost - Generally greaterPhasic Differences…….
24Biomechanics of Running Differences Between Walking and Running Always a Double Support PhaseNo Flight PhaseWalking
25Applied Biomechanics Biomechanics of Running Differences Between Walking and Running Always a Double Support PhaseNo Flight PhaseWalkingRunning -Never a Double Support PhaseAlways a flight PhaseRunning
26Running What’s Involved? Project body vertically/horizontallySufficient vertical/horizontal impulseFlightDissipate impactAppropriate vertical/horizontal impulseMaintain balance in single supportRe-position limbs
27How is Propulsion Produced? Propulsive ForceSegment motionNewtons 3rdTransfer of MomentumFree legArms
28How is Momentum Dissipated? Foot MechanismAnkle MechanismKnee MechanismShoe MechanismSurface Mechanism
33Running - Joint ROM Adaptations AnkleIncreased PF/DFIncreased pronation/supinationKneeIncreased flexion in early stance and swingHipIncreased flexion and extensionPelvisIncreased transverse plane rotationArmsIncreased shoulder ROMIncreased elbow flexion
34RearFoot Motion in Running Sub-talar Joint MotionIncreases duration of impact - facilitates dissipation of momentumLocks/un-locks mid-foot - adaptation to terrainProvides rigidity for propulsionDynamic Measurement - rearfoot angleRelationship between calcaneus and shank***FootTrak***
37Biomechanics of Running Issues? Surface/Shoe Cushioning.. Versus.. Energy CostThe Problem !!!
38Biomechanics of Running Issues? What Factors Influence Speed ???Speed = Stride Length x Stride RateStride Length Anthropometric Factors Strength Flexibility Neuromuscular FactorsStride Rate Neuromuscular Factors TechniqueCan Running Speed be Improved ???Yes !!!!!!!
39Biomechanics of Running Issues? What Factors Influence Energy Cost ???SpeedVertical Displacement“Extra” MotionOptimum Stride Length…Stride Rate RelationshipCan Running Efficiency be Improved ???Yes……..but!
40Injuries – A Biomechanical Origin Biomechanics of Running Issues?Injuries – A Biomechanical OriginMost running injuries have a biomechanical origin !!Issues –ForceInability to dissipate forceRepetition