Transcript Biomechanics of Walking and Running

Biomechanics of Gait
Walking
E. Muybridge
Biomechanics of Gait
Walking
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 Gait
Walking
Describing the Gait Cycle
Characteristics of Walking
Cyclic
Universal Pattern
Bi-laterally symmetric
Range of Speeds
Adaptable to Varied Surfaces
Efficient
Biomechanics of Gait
Walking
Describing the Gait Cycle
Phases of the Gait Cycle
Stance Phase
 Initial Double Limb Support
 Single Limb Support
 Terminal Double Limb Support
Swing Phase
 Initial Swing
 Terminal Swing
Biomechanics of Gait
Walking
When we walk, what must happen ??
Control Forces
Produce
Resist
Dissipate
Biomechanics of Gait
Walking
Objectives
Control Forces
Maintain Balance
Biomechanics of Gait
Walking
Objectives
Resist/Dissipate Forces
Maintain Balance
Move Body in Intended Direction
Biomechanics of Gait
Walking
Objectives
Resist/Dissipate Forces
Maintain Balance
Move Body in Intended Direction
Conserve Energy
Biomechanics of Gait
Walking
Produce/Resist /Dissipate Force
Source of Forces
Gravity
Muscle Contraction
Inertia
Direction of Forces
Vertical
Fore/Aft
Medial Lateral
Magnitude of Forces
.1 to 1.2 BW’s
Biomechanics of Gait
Walking
Produce/Resist /Dissipate Force
Forces produce moments (torques)
that….
Cause rotations –
Total Body
Joint
Segment
Biomechanics of Gait
Walking
Maintain Balance
Walking……..a series of catastrophes
narrowly averted……
The Issues –
Dynamic Movement
Influenced by external factors
Single versus Double Support
Depends on Multiple Systems
Adaptations in Base of Support
Biomechanics of Gait
Walking
Move Body in Intended Direction
Re-Positioning of Center of Gravity
Re-Positioning of Limb Segments
Force Production applied to the ground
Biomechanics of Gait
Walking
Conserve Energy
The Six Determinants of Gait (Inman, et. al.)
Biomechanics of Gait
Walking
The Six Determinants of Gait
Underlying Concept
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
Biomechanics of Gait
Walking
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 Gait
Walking
Role 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 Gait
Walking
At Ground Contact
Lateral Side
Contact Made on the Lateral
Border of the Heel
Foot is Supinated
Foot is Rigid
Medial Side
Biomechanics of Gait
Walking
Early Stance to MidStance
Lateral Side
Foot is Pronated
Foot is Mobile (flexible)
Enhances Balance
Medial Side
Biomechanics of Gait
Walking
Late Stance to Toe-Off
Lateral Side
Foot is Supinated
Foot is Rigid
Enhances Propulsion
Medial Side
Biomechanics of Gait
Walking
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 Gait
Running
Biomechanics of Gait
Running
Running:
 As a component of
competitive sport
 As a recreational activity
 As a stage of motor
development
 As a cause of injury
Biomechanics of Gait
Running
Differences between walking and running
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Velocity - Greater range than walking
Kinematic Parameters - Increase in most
Kinetic Parameters - Increase in some
Energy Cost - Generally greater
Phasic Differences…….
Biomechanics of Running
Differences Between Walking and Running
 Walking  Always a Double Support Phase
 No Flight Phase
Walking
Applied Biomechanics
Biomechanics of Running
Differences Between Walking and Running
 Walking  Always a Double Support Phase
 No Flight Phase
Walking
 Running  Never a Double Support Phase
 Always a flight Phase
Running
Running
What’s Involved?
 Project body vertically/horizontally
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 Sufficient vertical/horizontal
impulse
Flight
Dissipate impact
 Appropriate vertical/horizontal
impulse
Maintain balance in single support
Re-position limbs
How is Propulsion Produced?
 Propulsive Force
 Segment motion
 Newtons 3rd
 Transfer of Momentum
 Free leg
 Arms
How is Momentum Dissipated?
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Foot Mechanism
Ankle Mechanism
Knee Mechanism
Shoe Mechanism
Surface
Mechanism
Walking/Running Forces
GRF Differences
Running
Walking
Ground Reaction Forces in
Running
 GRF’s Influenced by
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Velocity
Vertical Displacement
Shoes
Surface
 GRF’s Influence
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Foot Pressures
Joint Forces
Joint Moments
Impact Shock
Braking/Propelling GRF in
Running
M/L GRF in Running
Running - Joint ROM
Adaptations
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Ankle
 Increased PF/DF
 Increased pronation/supination
Knee
 Increased flexion in early stance
and swing
Hip
 Increased flexion and extension
Pelvis
 Increased transverse plane
rotation
Arms
 Increased shoulder ROM
 Increased elbow flexion
RearFoot Motion in Running
 Sub-talar Joint Motion
 Increases duration of impact - facilitates
dissipation of momentum
 Locks/un-locks mid-foot - adaptation to terrain
 Provides rigidity for propulsion
 Dynamic Measurement - rearfoot angle
 Relationship between calcaneus and shank
 ***FootTrak***
Rearfoot Motion - Too Much…Too Little
Running Shoes
Issues
Biomechanics of Running
Issues?
Surface/Shoe Cushioning.. Versus.. Energy Cost
The Problem !!!
Biomechanics of Running
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 Running
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 Running
Issues?
Injuries – A Biomechanical Origin
Most running injuries
have a biomechanical
origin !!
Issues –
Force
Inability to dissipate
force
Repetition