Biomechanics of Gait Walking

1
Biomechanics of GaitWalking
E. Muybridge
2
Biomechanics of GaitWalking
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
3
Describing the Gait Cycle
Biomechanics of GaitWalking
Characteristics of Walking Cyclic Universal
Pattern Bi-laterally symmetric Range of
Speeds Adaptable to Varied Surfaces Efficient
4
Describing the Gait Cycle
Biomechanics of GaitWalking
Phases of the Gait Cycle

• Stance Phase
• Initial Double Limb Support
• Single Limb Support
• Terminal Double Limb Support

• Swing Phase
• Initial Swing
• Terminal Swing

5
Biomechanics of GaitWalking
When we walk, what must happen ??
Control Forces Produce Resist
Dissipate
6
Biomechanics of GaitWalking
Objectives
Control Forces Maintain Balance
7
Biomechanics of GaitWalking
Objectives
Resist/Dissipate Forces Maintain Balance Move
Body in Intended Direction
8
Biomechanics of GaitWalking
Objectives
Resist/Dissipate Forces Maintain Balance Move
Body in Intended Direction Conserve Energy
9
Biomechanics of GaitWalking
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 BWs
10
Biomechanics of GaitWalking
Produce/Resist /Dissipate Force
Forces produce moments (torques) that.
Cause rotations Total Body
Joint Segment
11
Biomechanics of GaitWalking
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
12
Biomechanics of GaitWalking
Move Body in Intended Direction
Re-Positioning of Center of Gravity Re-Positioning
of Limb Segments Force Production applied to the
ground
13
Biomechanics of GaitWalking
Conserve Energy
The Six Determinants of Gait (Inman, et. al.)
14
Biomechanics of GaitWalking
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
15
Biomechanics of GaitWalking
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
16
Role of Foot Motion
Biomechanics of GaitWalking
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
17
Biomechanics of GaitWalking
At Ground Contact
Lateral Side
Medial Side
Contact Made on the Lateral Border of the
Heel Foot is Supinated Foot is Rigid
18
Biomechanics of GaitWalking
Early Stance to MidStance
Lateral Side
Medial Side
Foot is Pronated Foot is Mobile
(flexible) Enhances Balance
19
Biomechanics of GaitWalking
Late Stance to Toe-Off
Lateral Side
Medial Side
Foot is Supinated Foot is Rigid Enhances
Propulsion
20
Biomechanics of GaitWalking
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
21
Biomechanics of GaitRunning
22
Biomechanics of GaitRunning
Running

• As a component of competitive sport
• As a recreational activity
• As a stage of motor development
• As a cause of injury

23
Biomechanics of GaitRunning
Differences between walking and running

• Velocity - Greater range than walking
• Kinematic Parameters - Increase in most
• Kinetic Parameters - Increase in some
• Energy Cost - Generally greater
• Phasic Differences.

24
Biomechanics of RunningDifferences Between
Walking and Running

• Walking -
• Always a Double Support Phase
• No Flight Phase

Walking
25
Applied BiomechanicsBiomechanics of
RunningDifferences 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
26
RunningWhats Involved?

• Project body vertically/horizontally
• Sufficient vertical/horizontal impulse
• Flight
• Dissipate impact
• Appropriate vertical/horizontal impulse
• Maintain balance in single support
• Re-position limbs

27
How is Propulsion Produced?

• Propulsive Force
• Segment motion
• Newtons 3rd
• Transfer of Momentum
• Free leg
• Arms

28
How is Momentum Dissipated?

• Foot Mechanism
• Ankle Mechanism
• Knee Mechanism
• Shoe Mechanism
• Surface Mechanism

29
Walking/Running ForcesGRF Differences
Running
Walking
30
Ground Reaction Forces in Running

• GRFs Influenced by
• Velocity
• Vertical Displacement
• Shoes
• Surface
• GRFs Influence
• Foot Pressures
• Joint Forces
• Joint Moments
• Impact Shock

31
Braking/Propelling GRF in Running
32
M/L GRF in Running
33
Running - Joint ROMAdaptations

• 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

34
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

35
Rearfoot Motion - Too MuchToo Little
36
Running ShoesIssues
37
Biomechanics of Running Issues?
Surface/Shoe Cushioning.. Versus.. Energy Cost
The Problem !!!
38
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 !!!!!!!
39
Biomechanics of Running Issues?
What Factors Influence Energy Cost ???
Speed Vertical Displacement Extra
Motion Optimum Stride LengthStride Rate
Relationship
Can Running Efficiency be Improved ???
Yes..but!
40
Biomechanics of Running Issues?
Injuries A Biomechanical Origin
Most running injuries have a biomechanical origin
!! Issues Force Inability to dissipate
force Repetition