Biomechanics of Gait Walking E. Muybridge. Applications Walking as a Critical Fundamental Movement...

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Biomechanics of GaitBiomechanics of GaitWalkingWalking

E. Muybridge

Applications

•Walking as a Critical Fundamental Movement Pattern

•Walking as a Recreational Activity

• Walking as a Modality for Rehabilitation

• Walking as a Competitive Sport

• Influence of Injury/Disease/Disability on Walking

• Aging Effects on Walking and Implications Independence

• Footwear Issues

• Energy Cost

E. Muybridge

Describing the Gait CycleDescribing the Gait Cycle

Characteristics of WalkingCharacteristics of Walking

CyclicCyclic

Universal PatternUniversal Pattern

Bi-laterally symmetricBi-laterally symmetric

Range of SpeedsRange of Speeds

Adaptable to Varied SurfacesAdaptable to Varied Surfaces

EfficientEfficient

Describing the Gait CycleDescribing the Gait CyclePhases of the Gait Cycle

Stance PhaseStance Phase Initial Double Limb SupportInitial Double Limb Support Single Limb SupportSingle Limb Support Terminal Double Limb SupportTerminal Double Limb Support

Swing PhaseSwing Phase Initial SwingInitial Swing Terminal SwingTerminal Swing

When we walk, what must happen ??

Control Forces Produce Resist Dissipate

Objectives

Control Forces

Maintain Balance

Objectives

Resist/Dissipate Forces

Maintain Balance

Move Body in Intended Direction

Objectives

Resist/Dissipate Forces

Maintain Balance

Conserve Energy

Produce/Resist /Dissipate Force

Source of Forces

Gravity Muscle Contraction

Inertia

Magnitude of Forces

.1 to 1.2 BW’s

Direction of Forces

VerticalFore/AftMedial Lateral

Produce/Resist /Dissipate Force

Forces produce moments (torques) that….

Cause rotations –

Total Body Joint Segment

Maintain Balance

The Issues –Dynamic MovementInfluenced by external factorsSingle versus Double SupportDepends on Multiple SystemsAdaptations in Base of Support

Walking……..a series of catastrophes narrowly averted……

Re-Positioning of Center of Gravity

Re-Positioning of Limb Segments

Force Production applied to the ground

Conserve Energy

The Six Determinants of Gait (Inman, et. al.)

Energy Expenditure = Work Done

Work = Force x Distance

Force = Mass x Acceleration

Therefore – the amount of energy we expend is directly related to the amount of mass we move and the extent and speed of movement

The Six Determinants of Gait

Underlying Concept

Determinants of Gait

Pelvic Rotation – transverse plane

Lateral Pelvic Tilt – frontal plane

Knee Flexion – during stance

Ankle PF - at Toe Off

Ankle DF – at Foot strike

Gait Width – frontal plane

Role of Foot MotionRole of Foot Motion

Objectives

To aid in force dissipation

To provide a mobile adapter

To provide a rigid lever for propulsion

Mechanism - Sub-talar Joint Motion

A Tri-planar motion PF and DF Inversion/Eversion AB/ADduction

Lateral Side Medial Side

At Ground Contact

Contact Made on the Lateral Border of the Heel

Foot is Supinated

Foot is Rigid

Early Stance to MidStance

Foot is Pronated

Foot is Mobile (flexible)

Enhances Balance

Late Stance to Toe-Off

Foot is Supinated

Foot is Rigid

Enhances Propulsion

Pronation/Supination Issues:

Too Little – Loss of force dissipation Loss of Mobility – Balance Stress Injury

Too Much Relationship to Tibial Rotation Associated Patellar Tracking Issues Soft-Tissue Stress

Control of Pronation/Supination Shoe Design Orthotics Muscle Strengthening – Posterior Tib

Biomechanics of GaitBiomechanics of GaitRunningRunning

As a component of As a component of competitive sportcompetitive sport

As a recreational activityAs a recreational activity As a stage of motor As a stage of motor

developmentdevelopment As a cause of injuryAs a cause of injury

Running:

Velocity - Greater range than walkingVelocity - Greater range than walking Kinematic Parameters - Increase in mostKinematic Parameters - Increase in most Kinetic Parameters - Increase in someKinetic Parameters - Increase in some Energy Cost - Generally greaterEnergy Cost - Generally greater Phasic Differences…….Phasic Differences…….

Differences between walking and running

Walking -Walking - Always a Double Support PhaseAlways a Double Support Phase No Flight PhaseNo Flight Phase

Walking

Biomechanics of RunningBiomechanics of RunningDifferences Between Walking and RunningDifferences Between Walking and Running

Walking -Walking - Always a Double Support PhaseAlways a Double Support Phase No Flight PhaseNo Flight Phase

Walking

Running

Running -Running - Never a Double Support PhaseNever a Double Support Phase Always a flight PhaseAlways a flight Phase

Applied BiomechanicsApplied BiomechanicsBiomechanics of RunningBiomechanics of Running

Differences Between Walking and RunningDifferences Between Walking and Running

RunningRunningWhat’s Involved?What’s Involved?

Project body vertically/horizontallyProject body vertically/horizontally Sufficient vertical/horizontal Sufficient vertical/horizontal

impulseimpulse FlightFlight Dissipate impactDissipate impact

Appropriate vertical/horizontal Appropriate vertical/horizontal impulseimpulse

Maintain balance in single supportMaintain balance in single support Re-position limbsRe-position limbs

How is Propulsion Produced?How is Propulsion Produced?

Propulsive ForcePropulsive Force Segment motionSegment motion Newtons 3rdNewtons 3rd

Transfer of MomentumTransfer of Momentum Free legFree leg ArmsArms

How is Momentum Dissipated?How is Momentum Dissipated?

Foot MechanismFoot Mechanism Ankle MechanismAnkle Mechanism Knee MechanismKnee Mechanism Shoe MechanismShoe Mechanism Surface Surface

MechanismMechanism

Walking/Running ForcesWalking/Running ForcesGRF DifferencesGRF Differences

Walking

Running

Ground Reaction Forces in Ground Reaction Forces in RunningRunning

GRF’s Influenced byGRF’s Influenced by VelocityVelocity Vertical DisplacementVertical Displacement ShoesShoes SurfaceSurface

GRF’s InfluenceGRF’s Influence Foot PressuresFoot Pressures Joint ForcesJoint Forces Joint MomentsJoint Moments Impact ShockImpact Shock

Braking/Propelling GRF in Braking/Propelling GRF in RunningRunning

M/L GRF in RunningM/L GRF in Running

Running - Joint ROMRunning - Joint ROMAdaptationsAdaptations

AnkleAnkle Increased PF/DFIncreased PF/DF Increased pronation/supinationIncreased pronation/supination

KneeKnee Increased flexion in early stance Increased flexion in early stance

and swingand swing HipHip

Increased flexion and extensionIncreased flexion and extension PelvisPelvis

Increased transverse plane Increased transverse plane rotationrotation

ArmsArms Increased shoulder ROMIncreased shoulder ROM Increased elbow flexionIncreased elbow flexion

RearFoot Motion in RunningRearFoot Motion in Running

Sub-talar Joint MotionSub-talar Joint Motion Increases duration of impact - facilitates Increases duration of impact - facilitates

dissipation of momentumdissipation of momentum Locks/un-locks mid-foot - adaptation to terrainLocks/un-locks mid-foot - adaptation to terrain Provides rigidity for propulsionProvides rigidity for propulsion Dynamic Measurement - rearfoot angleDynamic Measurement - rearfoot angle

Relationship between calcaneus and shankRelationship between calcaneus and shank ***FootTrak******FootTrak***

Rearfoot Motion - Too Much…Too LittleRearfoot Motion - Too Much…Too Little

Running ShoesRunning ShoesIssuesIssues

Biomechanics of RunningBiomechanics of Running Issues? Issues?

The Problem !!!

Surface/Shoe Cushioning.. Versus.. Energy Cost

What Factors Influence Speed ???

Speed = Stride Length x Stride Rate

Stride Length Anthropometric Factors Strength Flexibility Neuromuscular Factors

Stride Rate Neuromuscular Factors Technique

Can Running Speed be Improved ???

Yes !!!!!!!

What Factors Influence Energy Cost ???

Vertical Displacement

“Extra” Motion

Optimum Stride Length…Stride Rate Relationship

Can Running Efficiency be Improved ???

Yes……..but!

Injuries – A Biomechanical Origin

Most running injuries have a biomechanical origin !!

Issues –

Inability to dissipate force

Repetition

Biomechanics of Gait Walking E. Muybridge. Applications Walking as a Critical Fundamental Movement...

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