Gait

Gait Analysis

Overview
Gait can be assessed clinically or with greater accuracy in a gait analysis lab. This section discusses the prerequisites, determinants, and abnormalities in gait, offering a comprehensive understanding of both normal and pathological gait patterns.

Pre-requisites for Normal Walking

There are five key prerequisites to achieve a normal walking gait, summarized by the acronym SAFE Pre-positioning:

  1. Stable stance phase
  2. Adequate step distance
  3. Foot clearance during swing
  4. Energy conservation
  5. Pre-positioning of the foot in swing phase

Determinants of Gait

The following factors ensure smooth and efficient movement during walking:

Determinants Description
Pelvic tilt Helps smooth the gait cycle.
Pelvic lateral displacement Minimizes vertical oscillation.
Pelvic rotation Increases stride length.
Knee flexion Allows foot clearance and absorbs impact.
Ankle and foot motion Facilitates propulsion and stability.

The Gait Cycle

The gait cycle begins when the foot strikes the ground and ends when the same foot strikes again, with one cycle equal to one stride.

  • Stance Phase (60% of the gait cycle)
  • Swing Phase (40% of the gait cycle)

Mnemonic: I Like My Tea Put In My Teapot

  1. Stance Phase
    1. Initial contact (heel strike)
    2. Loading
    3. Mid-stance
    4. Terminal stance
    5. Pre-swing (toe-off)
  2. Swing Phase
    1. Initial swing
    2. Mid-swing
    3. Terminal swing

Clinical Assessment of Gait Phases

In practice, clinicians focus on four primary phases:

  1. Weight acceptance
    • Initial contact and loading
  2. Stance
    • Mid-stance and terminal stance
  3. Forward progression
    • Terminal stance and pre-swing
  4. Swing
    • Includes all swing phases

Important Gait Definitions

Term Definition
Step Distance from one foot contact to the opposite foot contact.
Stride Distance from one foot contact to the same foot making contact again.
Cadence Number of steps taken per unit time.
Double support phase When both feet are in contact with the ground.
Float phase When neither foot is in contact with the ground (occurs in running).
Velocity Stride length divided by stride time (meters/second).
Walking base Distance between the heels when standing still.
Foot progression angle Angle of foot direction in relation to the midline, described as positive or negative.

Clinical Gait Analysis

A clinical gait analysis involves inspecting the pelvis, knees, ankles, and feet during the gait cycle. Below is a summary of the normal movements seen during gait:

Joint Movement
Pelvis Rotates anteriorly at heel strike, posteriorly at toe-off, and tilts during swing.
Hip Flexion aids clearance; extension prevents collapse.
Knee Hamstrings cushion heel strike and aid swing; quads stabilize during loading.
Ankle Follows a three-rocker motion: controlled plantarflexion, dorsiflexion control, and push-off.

3D Gait Analysis

Advanced 3D gait analysis is particularly useful for analyzing complex gait patterns, such as those seen in cerebral palsy. This type of analysis examines:

  • Kinematics – Motion patterns
  • Kinetics – Forces required for motion
  • Plantar pressure profiles – Weight-bearing patterns on the foot
  • EMG – Muscle firing patterns
  • Efficiency – Oxygen and energy consumption

Abnormalities of Gait

Trendelenberg Gait
- Trunk bends laterally toward the standing leg due to weak or painful hips.

Anterior Trunk Bending
- Seen when patients bend forward to compensate for knee extension issues or quad weakness.

Posterior Trunk Bending
- Occurs due to weak hip extensors, resulting in compensatory trunk movements.

Pathological Gait Patterns

Pathologic Gait Description
Steppage Gait Caused by equinus deformity.
Hip Scissoring Gait Due to spastic adductors.
Antalgic Gait Shortened stance time on a painful limb.
Quadriceps Avoidance Gait Seen in ACL-deficient knees.
Shuffling Gait Due to weakness or fear of falling, often associated with Parkinson’s disease.

Muscle Activity During Gait

Muscle groups play specific roles throughout the gait cycle:

  • Dorsiflexors are concentric throughout the swing phase and eccentric at initial contact and loading.
  • Plantarflexors are inactive during the swing phase, but eccentric in mid-stance and concentric during pre-swing (toe-off).
Back to top