Gait: Functions & Analysis

Sagittal plane

The x plane

MOTION

• Flexion / Extension

  • e.g., knee flexion

MEASURED

• within the anteroposterior plane

Frontal / coronal plane

The y plane

MOTION

• Adduction / Abduction

  • e.g., knee valgus

MEASURED

• within the mediolateral plane

Transverse plane

The z plane

MOTION

• Internal / External rotation

  • e.g., knee rotation

MEASURED

• within the axial / horizontal plane

Phases of the Gait Cycle

1. Stance 0%-62%

2. Swing 62%-100%

Subphases of the Gait Cycle

1. Initial Contact 0%-2%

2. Loading Response 2%-12%

3. Mid Stance 12%-31%

4. Terminal Stance 31%-50%

5. Pre Swing 50%-62%

6. Initial Swing 62%-75%

7. Mid Swing 75%-87%

8. Terminal Swing 87%-100%

Events of Gait Cycle

1. Left Heel Strike (Initial Contact) - 0%

2. Right Toe Off (Opposite Foot) - 12%

3. Left Heel Rise - 31%

4. Right Heel Strike (Opposite Foot) - 50%

5. Left Toe Off - 61%

6. Foot Adjacent - 75%

7. Left Tibia Vertical - 87%

8. Left Heel Strike (Initial Contact) - 100%

Tasks of Gait Cycle

1. Weight Acceptance 0%-12%

2. Single Limb Stance 12%-50%

3. Swing Limb Advancement 50%-100%

Stride

One full gait cycle — same foot, contact to contact.

Step

One foot’s contact to the other foot’s contact

Two steps make a stride

they should be equal in normal gait.

Stride width

Side-to-side distance between the two feet.

Temporal parameters

1. Cadence

2. Velocity

3. Walking Speed

4. Comfortable Walking Speed

Cadence

Steps per minute

approx. 100–115 steps/min in healthy adults

Walking speed

Distance over time

approx. 1.2–1.3 m/s in healthy adults

Velocity

cadence × step length

Comfortable walking speed

Self-selected pace

least energy consumed per unit distance

What happens as you change from walking to running

Walking faster

• Stance phase → decreases

• Swing phase → increases

• Double support → decreases

Running

• Fast walking without double support

• Double support disappears — a double-float

• Stance / swing ratio reverses

Subphase: Initial Contact

0-2%

• The instant the foot meets the floor.

• Limb position here sets the loading pattern.

• OBJECTIVES

  • Start the stance phase

  • Decelerate the impact

Subphase: Loading Response

2–12%

• First double-support period.

• Body weight transfers onto the limb.

• OBJECTIVES

  • Shock absorption

  • Weight-bearing stability

  • Preserve progression

Subphase: Mid-Stance

12-30%

• First half of single-limb support.

• Ends as weight aligns over the forefoot.

• OBJECTIVES

  • Progress over a stationary foot

  • Limb & trunk stability

Subphase: Terminal Stance

31-50%

• Begins with heel rise

• Body moves ahead of the forefoot

• OBJECTIVES

  • Progress over a stationary foot

  • Limb and trunk stability

Subphase: Pre-Swing

51-62%

• Second double support; the limb unloads and readies to swing.

Subphase: Initial-Swing

63-75%

• Foot lifts and clears the floor; the limb advances

Subphase: Mid-Swing

76-87%

Limb advances until the tibia is vertical.

Subphase: Terminal-Swing

88-100%

Shank moves ahead of the thigh; limb readies for contact.

The body as two working subunits

1. Passenger

• Head, arms & trunk (HAT) — carried along, kept balanced over the limbs.

2. Locomotor

• Pelvis & the two lower limbs — the machinery that produces walking.

Passenger unit

• aka HAT

• Head, neck, trunk & arms — about 70% of body mass

• Muscles keep the spine aligned with minimal postural change

• Balance depends on instantaneous alignment

• Center of mass sits ~1/3 of the way from hip to shoulder joint center

Locomotor unit

• Two lower limbs plus the pelvis

• 11 major joints, controlled by 57 muscles

• Pelvis links the limbs to the passenger unit

• Advances the limb during swing