Unit 6

Gait Terminology and Descriptors

Definition of Human Gait

Human gait refers to the complex process of walking, characterized by the forward propulsion of the body's center of mass along a predetermined path. This movement must be performed while maintaining stability to achieve several crucial goals:

  • Prevent Injury: Ensuring that movements do not lead to falls or musculoskeletal issues.

  • Maximize Efficiency: Walking should be performed with as little energy expenditure as possible, considering factors like speed and endurance.

  • Absorb Ground Impact: The body must effectively manage the forces generated upon contact with the ground to protect joints and tissues.

Primary Tasks of Gait

The primary tasks integral to an effective gait cycle include:

  • Weight Acceptance: Initially, the body must appropriately transfer weight onto the weight-bearing limb upon foot strike.

  • Single Leg Stance: The weight-bearing leg must maintain balance for a fraction of the gait cycle.

  • Swing Leg Advancement: The non-weight-bearing leg must be efficiently moved forward to prepare for the next step.

Requirements for Effective Gait

For an individual to maintain a standard gait pattern, several requirements must be fulfilled:

  • Sufficient Muscular Strength: Adequate strength is necessary for advancing the body and maintaining balance during motion.

  • Postural Control: Maintaining correct alignment and orientation of the body is crucial for both safety and efficiency.

  • Adaptability: The ability to adapt to environmental changes through sensory-motor interaction is important for safe navigation, especially on uneven terrain.

Importance of Gait Assessment

Gait assessment is a key component in physical therapy and rehabilitation. The evaluation of gait patterns aids professionals in:

  • Diagnosis: Identifying underlying conditions or injuries that may impact mobility.

  • Intervention: Developing tailored rehabilitation programs based on specific gait deficiencies.

  • Documentation: Accurate recording of gait characteristics is essential for monitoring progress and treatment outcomes.

Gait Cycle

Definition of Gait Cycle

The gait cycle is defined as the sequence of events occurring from the heel strike of one foot to the subsequent heel strike of the same foot. This cycle can be divided into key phases:

  • Reference Limb: The limb of interest during the assessment that provides a baseline for analysis.

Phases of Gait

The gait cycle is divided into two primary phases:

  • Stance Phase (60%): The phase where the limb is in contact with the ground, ensuring stability and support. This phase encompasses five distinct periods.

  • Swing Phase (40%): The phase where the limb is off the ground, allowing for forward progression, consisting of two periods.

Familiarization with the active muscle groups during each period of these phases is vital for effective assessment.

Gait Parameters

Temporal Descriptors

  • Cadence: Refers to the number of steps taken per minute, an indicator of walking speed.

  • Stride Time: The duration required to complete one cycle of gait from heel strike to heel strike of the same foot.

  • Step Time: The time taken for one foot to complete a step, measured from heel strike to heel strike of the opposite foot.

Spatial Descriptors

  • Stride Length: The distance covered between two successive heel strikes of the same foot, with an average of 144 cm in adults.

  • Step Length: The distance measured between the heel strike of one foot to the heel strike of the other foot.

  • Base Width: The lateral distance between the heel centers during successive foot contacts, typically ranging from 8-10 cm in normal walking.

  • Foot Angulation: The natural outward angle of the toes, averaging 5-7 degrees from the midline.

  • Gait Velocity: The speed of walking, calculated as the distance covered per unit of time, which is significantly influenced by both stride length and cadence.

    • Normal Walking Speeds: On average, men walk at speeds of approximately 1.4 m/s while women average around 1.3 m/s.

Impact of Gait Speed

Individuals exhibiting a walking speed of less than 1 m/s may experience:

  • Decreased Functional Abilities: Limitations in performing daily activities.

  • Higher Rates of Falls, Hospitalization, and Mortality: Increased risk of adverse health outcomes.

This threshold has led to gait speed being proposed as the 6th Vital Sign, underlining its importance during health assessments alongside traditional vital signs like blood pressure and heart rate.

Changes in Gait with Aging

Pediatric Gait Development

Early gait patterns are characterized by instability, which gradually evolves to greater stance stability and skilled movements, reaching significant refinement by around age seven.

Geriatric Gait Changes

Older adults exhibit various changes in their gait, including:

  • Shorter Single-Limb Stance Durations: Reduced time spent on one leg, affecting balance.

  • Wider Base of Support: A tendency to spread the feet further apart to maintain stability.

  • Decreased Step and Stride Lengths: Shortened steps can impact speed and efficiency.

  • Increased Reliance on Visual Input: Older adults may depend more on visual cues for balance due to diminishing sensory functions.

Physiological Changes with Aging

Several physiological factors contribute to altered gait patterns in older adults, such as:

  • Sarcopenia: The loss of muscle mass and strength impairs mobility.

  • Decreased Flexibility: Reduced range of motion in joints affects gait mechanics.

  • Cardiovascular Issues: Impaired cardiovascular health can limit endurance and stamina during walking.

  • Changes in Visual and Vestibular Systems: Affect balance and coordination, increasing the risk of falls.

Balance Systems

Maintaining balance and coordination involves the intersection of sensory inputs, including:

  • Somatic Sensation: Proprioceptive feedback from muscles and joints.

  • Visual Systems: Essential for spatial awareness and orientation.

  • Vestibular Systems: Integral for maintaining balance and spatial orientation in relation to gravity.

Measurement and Prediction

Gait speed serves as a powerful predictive measure for health outcomes and fall risk, particularly in older adults. Monitoring gait speed can provide valuable insights into an individual's overall health and functional capabilities.