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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
Biomechanics of GaitBiomechanics of GaitWalkingWalking
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
Biomechanics of GaitBiomechanics of GaitWalkingWalking
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
Biomechanics of GaitBiomechanics of GaitWalkingWalking
When we walk, what must happen ??
Control Forces Produce Resist Dissipate
Biomechanics of GaitBiomechanics of GaitWalkingWalking
Objectives
Control Forces
Maintain Balance
Biomechanics of GaitBiomechanics of GaitWalkingWalking
Objectives
Resist/Dissipate Forces
Maintain Balance
Move Body in Intended Direction
Biomechanics of GaitBiomechanics of GaitWalkingWalking
Objectives
Resist/Dissipate Forces
Maintain Balance
Move Body in Intended Direction
Conserve Energy
Biomechanics of GaitBiomechanics of GaitWalkingWalking
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
Biomechanics of GaitBiomechanics of GaitWalkingWalking
Produce/Resist /Dissipate Force
Forces produce moments (torques) that….
Cause rotations –
Total Body Joint Segment
Biomechanics of GaitBiomechanics of GaitWalkingWalking
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……
Biomechanics of GaitBiomechanics of GaitWalkingWalking
Move Body in Intended Direction
Re-Positioning of Center of Gravity
Re-Positioning of Limb Segments
Force Production applied to the ground
Biomechanics of GaitBiomechanics of GaitWalkingWalking
Conserve Energy
The Six Determinants of Gait (Inman, et. al.)
Biomechanics of GaitBiomechanics of GaitWalkingWalking
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
Biomechanics of GaitBiomechanics of GaitWalkingWalking
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
Biomechanics of GaitBiomechanics of GaitWalkingWalking
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
Biomechanics of GaitBiomechanics of GaitWalkingWalking
Lateral Side Medial Side
At Ground Contact
Contact Made on the Lateral Border of the Heel
Foot is Supinated
Foot is Rigid
Biomechanics of GaitBiomechanics of GaitWalkingWalking
Early Stance to MidStance
Lateral Side Medial Side
Foot is Pronated
Foot is Mobile (flexible)
Enhances Balance
Biomechanics of GaitBiomechanics of GaitWalkingWalking
Lateral Side Medial Side
Late Stance to Toe-Off
Foot is Supinated
Foot is Rigid
Enhances Propulsion
Biomechanics of GaitBiomechanics of GaitWalkingWalking
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 GaitWalkingWalking
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:
Biomechanics of GaitBiomechanics of GaitRunningRunning
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…….
Biomechanics of GaitBiomechanics of GaitRunningRunning
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
Biomechanics of RunningBiomechanics of Running Issues? Issues?
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 !!!!!!!
Biomechanics of RunningBiomechanics of Running Issues? Issues?
What Factors Influence Energy Cost ???
Speed
Vertical Displacement
“Extra” Motion
Optimum Stride Length…Stride Rate Relationship
Can Running Efficiency be Improved ???
Yes……..but!
Biomechanics of RunningBiomechanics of Running Issues? Issues?
Injuries – A Biomechanical Origin
Most running injuries have a biomechanical origin !!
Issues –
Force
Inability to dissipate force
Repetition