1. Phases of the Gait Cycle And Determinants of Gait
Human Locomotion
Phases of the Gait Cycle
And
Determinants of Gait

2. Understanding the Phasic Characteristics of Gait
Provides a logical framework for discussion of gait
Provides a logical structure for analyzing gait
Provides a common set of terms for communicating information about gait

3. Basic Gait Phase Terminology
Gait Cycle
Stance and Swing
Stride Length - units?
Step Length - units?
Stride (gait) Width
Stride Time
Stance Time
Swing Time
Cadence
Velocity

4. Phases of the Gait Cycle
How would you define the Phases of the Gait Cycle ?

5. Phases of the Gait Cycle
Stance Phase
Initial Double Support
Single Support
Terminal Double Support
Swing Phase
Initial Swing
Terminal Swing
TSw
ISw DS DS SS
Stance
Swing
Gait Cycle

6. Phases - Percentage of Gait Cycle
Normal Walking
Stance - 60 % of the Complete Gait Cycle
Single Stance – 30% - 40%
Double Stance - 20% - 30%
Swing - 40 %
Slow/Fast Walking
Slow – Stance Phase percentage Increases
Fast – Stance Phase percentage decrease
Pathological Gait – generally, stance phase percentage increases
Double support increased

7. Gait Events Support Events Swing Events Foot (Heel) Strike Foot Flat
Midstance
Heel Off
Foot (Toe) Off
Swing Events
Foot (Toe) Off
Midswing
Foot (Heel) Strike

8. Gait Events Foot (heel) Strike
Initial Contact
Beginning of Loading
Foot Position may vary, but is generally supinated
Represents end of single support on the opposite side

9. Gait Events Foot Flat Maximum Impact Loading occurs
Controlled by the Ant Tib
Foot rapidly moves into pronation
Weight has been shifted to the support leg
Coincides with end of the Initial period of Double Support on the Opposite side

10. Gait Events Mid-Stance
Single Support
Balance Critical
All weight supported by single leg
Foot remains pronated initially then re-supinates
Late mid-stance is the period of max propulsion
Swing occurring on opposite

11. Gait Events Heel-Off Un-loading of limb and preparation for swing
Foot Strike on Opposite Side
Weight Shift to opposite side begins

12. Gait Events Toe-Off Weight transition to opposite side completed
Hip flexion has been initiated to facilitate swing
Coincides with beginning of single support on the opposite side

13. Gait Events Mid-swing
Leg shortened (ankle dorsiflexion) and hip elevated (abducted) to facilitate swing
Mid-stance on the opposite side
C. Of G. directly over opposite supporting foot

14. Gait Events Terminal Swing
Hip flexion stopped and knee extended via Mo
Foot supinated and positioned for foot strike
Coincides with the end of the second DS phase on the opposite side
The Sequence Begins Again

15. How do we Manipulate Walking Velocity

16. How do we Manipulate Walking Velocity
Stride Length
Cadence
Manipulation of Velocity
Initial Adjustment -
Secondary Adjustment

17. Human Gait
Why do we walk the way we do????

18. Considerations: Anatomy Manipulation of Objects Vision Speed
Efficiency

19. Efficiency Movement Requires Force
Work = Force x Distance Increases in force and/or distance reflect increased work
Amount of Work Determines Energy Expenditure

20. Efficiency
Non-functional Movement of the C. of G. is Energy Expensive !!!

21. Efficiency
Movement of the Body’s Center of Gravity Reflects Collective Movement of the Body
Thus
Minimizing the Movement of the Body’s Center of Gravity during Locomotion is the Major Factor in Minimizing the Body’s Expenditure of Energy

22. ** Efficiency ** Factors Determining Energy Cost
Determinants on Gait: (Saunders, Inman, Whittle, etc.)
Knee Flexion During Stance
Pelvic Rotation (transverse plane)
Pelvic Lateral Tilt (Obliquity)
Ankle Mechanism (Dorsiflexion)
Ankle Mechanism (Plantarflexion)
Step Width

23. Pelvic Rotation

24. Pelvic Lateral Tilt

25. Knee Flexion During Stance

26. Ankle Mechanism Plantar Flexion
Lengthens the leg during stance

27. Ankle Mechanism Dorsiflexion
Lengthens Leg During Swing, prior to foot contact

28. Step Width
Narrowing the base during double stance reduces lateral motion