1. Biomechanics of Gait Walking
E. Muybridge

2. 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

3. Describing the Gait Cycle
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

4. Describing the Gait Cycle
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

5. Biomechanics of Gait Walking
When we walk, what must happen ??
Control Forces Produce Resist Dissipate

6. Biomechanics of Gait Walking
Objectives
Control Forces
Maintain Balance

7. Biomechanics of Gait Walking
Objectives
Resist/Dissipate Forces
Maintain Balance
Move Body in Intended Direction

8. Biomechanics of Gait Walking
Objectives
Resist/Dissipate Forces
Maintain Balance
Move Body in Intended Direction
Conserve Energy

9. 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

10. Biomechanics of Gait Walking Produce/Resist /Dissipate Force
Forces produce moments (torques) that….
Cause rotations –
Total Body Joint Segment

11. 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

12. 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

13. Biomechanics of Gait Walking
Conserve Energy
The Six Determinants of Gait (Inman, et. al.)

14. 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

15. 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

16. 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

17. Biomechanics of Gait Walking
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 Gait Walking
Early Stance to MidStance
Lateral Side
Medial Side
Foot is Pronated
Foot is Mobile (flexible)
Enhances Balance

19. Biomechanics of Gait Walking
Late Stance to Toe-Off
Lateral Side
Medial Side
Foot is Supinated
Foot is Rigid
Enhances Propulsion

20. 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

21. Biomechanics of Gait Running

22. Biomechanics of Gait 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 Gait Running
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 Running Differences Between Walking and Running
Always a Double Support Phase
No Flight Phase
Walking

25. Applied Biomechanics Biomechanics of Running Differences Between Walking and Running
Always a Double Support Phase
No Flight Phase
Walking
Running -
Never a Double Support Phase
Always a flight Phase
Running

26. Running What’s 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 Forces GRF Differences

30. Ground Reaction Forces in Running
GRF’s Influenced by
Velocity
Vertical Displacement
Shoes
Surface
GRF’s Influence
Foot Pressures
Joint Forces
Joint Moments
Impact Shock

31. Braking/Propelling GRF in Running

32. M/L GRF in Running

33. Running - Joint ROM Adaptations
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 Much…Too Little

36. Running Shoes Issues

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 Length…Stride Rate Relationship
Can Running Efficiency be Improved ???
Yes……..but!

40. Injuries – A Biomechanical Origin
Biomechanics of Running Issues?
Injuries – A Biomechanical Origin
Most running injuries have a biomechanical origin !!
Issues –
Force
Inability to dissipate force
Repetition