Overview
Gait refers to the pattern of walking produced by the coordinated activity of muscles, bones, joints and the nervous system. Analysis of gait is an important component of orthopaedic evaluation because abnormalities in walking pattern often indicate underlying musculoskeletal or neurological disorders.
The gait cycle describes the sequence of events that occur between two successive contacts of the same foot with the ground. Understanding the phases of the gait cycle allows clinicians to analyze abnormalities in walking and determine the underlying biomechanical causes.
Gait analysis is widely used in orthopaedics, rehabilitation medicine, neurology and sports medicine. It helps in diagnosing conditions such as limb length discrepancy, muscle weakness, joint deformities, nerve injuries and cerebral palsy.
Basic Terminology
Several terms are commonly used when describing normal walking mechanics.
| Term | Definition |
|---|---|
| Stride length | Distance between successive heel strikes of the same foot |
| Step length | Distance between heel strike of one foot and the opposite foot |
| Cadence | Number of steps taken per minute |
| Walking velocity | Speed of walking |
These parameters are useful in quantitative gait analysis and help clinicians assess functional mobility.
Phases of the Gait Cycle
The gait cycle is divided into two major phases: the stance phase and the swing phase.
- Stance phase accounts for approximately sixty percent of the gait cycle
- Swing phase accounts for approximately forty percent of the gait cycle
During the stance phase the foot remains in contact with the ground. During the swing phase the limb moves forward in preparation for the next step.
| Phase | Percentage of Gait Cycle |
|---|---|
| Stance phase | Approximately 60 percent |
| Swing phase | Approximately 40 percent |
Subdivisions of Stance Phase
The stance phase can be further divided into several functional stages that occur sequentially.
| Stage | Description |
|---|---|
| Heel strike | Initial contact of heel with the ground |
| Foot flat | Entire foot comes into contact with ground |
| Mid stance | Body weight passes over the supporting foot |
| Heel off | Heel lifts from ground |
| Toe off | Toes leave ground initiating swing phase |
These stages allow efficient transfer of body weight during walking.
Subdivisions of Swing Phase
The swing phase is also divided into stages representing the movement of the limb through the air.
| Stage | Description |
|---|---|
| Initial swing | Limb accelerates forward |
| Mid swing | Limb passes beneath body |
| Terminal swing | Limb decelerates before heel strike |
Determinants of Normal Gait
The determinants of gait are biomechanical features that minimize energy expenditure during walking. These mechanisms allow efficient forward movement while maintaining stability.
- Pelvic rotation
- Pelvic tilt
- Knee flexion during stance
- Foot and ankle mechanism
- Controlled lateral displacement of pelvis
- Vertical displacement of the body center of gravity
Together these determinants reduce vertical oscillation of the body and make walking more energy efficient.
Muscle Activity During Gait
Muscle groups play specific roles at different phases of the gait cycle.
| Muscle Group | Function During Gait |
|---|---|
| Gluteus maximus | Stabilizes hip during early stance |
| Quadriceps | Controls knee flexion during stance |
| Gastrocnemius and soleus | Provide push off during toe off |
| Tibialis anterior | Dorsiflexion during swing phase |
Proper coordination of these muscle groups ensures smooth and efficient walking.
Abnormal Gait Patterns
Several characteristic gait abnormalities occur in orthopaedic and neurological disorders.
- Antalgic gait due to pain
- Trendelenburg gait due to hip abductor weakness
- Steppage gait due to foot drop
- Spastic gait in upper motor neuron lesions
- Waddling gait in muscular dystrophy
Identification of these abnormal patterns helps clinicians determine the underlying pathology.
Clinical Methods of Gait Analysis
Gait analysis can be performed through several methods depending on clinical requirements.
- Observational gait analysis
- Video based motion analysis
- Force plate analysis
- Electromyography
- Three dimensional motion capture systems
Advanced gait laboratories combine these technologies to study complex movement patterns.
Clinical Importance in Orthopaedics
Understanding gait mechanics is essential in orthopaedic practice. Many musculoskeletal conditions alter normal walking patterns, and careful gait analysis helps identify functional impairments.
Gait analysis is particularly useful in evaluating limb length discrepancies, joint deformities, neuromuscular disorders and postoperative rehabilitation following orthopaedic procedures.
Exam Pearls
- Stance phase occupies about sixty percent of the gait cycle
- Swing phase occupies about forty percent of the gait cycle
- Heel strike marks the beginning of the gait cycle
- Trendelenburg gait occurs due to hip abductor weakness
- Tibialis anterior prevents foot drop during swing phase