Gait Analysis Study Notes (PTA 108)

Gait Analysis Study Notes

Gait Overview

• Gait is the coordinated sequence of body movements used to walk from one location to another.
• Key objective: understand how limb, pelvis, trunk, and arms coordinate to produce stable, efficient forward progression.
• Gait analysis in PTA contexts focuses on identifying impairments that alter cadence, step length, stride length, and walking speed, and matching patterns to possible etiologies.

Locomotion vs Mobility

• Mobility: body movements necessary to perform walking, wheeling, crawling.
• Locomotion: the means of moving from one location to another (walking, wheeling, crawling).

Standard Terminology vs Rancho Los Amigos Terminology

• Gait phases are described in two frameworks:
  • Stance Phase (60% of gait cycle)
  • Heel strike (initial contact)
  • Foot flat (loading response)
  • Midstance
  • Heel off (terminal stance)
  • Toe off (pre-swing)
  • Swing Phase (40% of gait cycle)
  • Acceleration (initial swing)
  • Midswing
  • Deceleration (terminal swing)
• Rancho Los Amigos terminology vs Standard terminology share the same phase concepts but use different labels for some events.

Gait Phases (Phase-by-Phase Details)

Each phase lists Rancho terminology, Standard terminology, muscular actions, joint actions, and weight-bearing status.

Initial Contact / Heel Strike

• Rancho terminology: Beginning of stance phase when the heel/foot touches the ground.
• Standard terminology: Instant the heel touches the ground.
• Muscular actions:
  • Ankle dorsiflexors activate dorsiflexion.
  • Quadriceps contract for knee extension.
  • Hamstrings stabilize knee and prevent hyperextension.
  • Hip extensors and abductors stabilize the trunk/pelvis over the leg.
• Weight bearing: Double support occurs (both feet on ground briefly).

Loading Response / Foot Flat

• Rancho terminology: Amount of time between initial contact and the beginning of the swing phase for the other leg.
• Standard terminology: The moment the entire foot makes contact with the ground.
• Muscular actions:
  • Ankle dorsiflexors eccentrically lower the foot to ground.
  • Quadriceps eccentrically contract to control knee flexion and accept weight of the body.
  • Plantar flexors eccentrically control dorsiflexion as the tibia moves over the foot.
  • Tibialis posterior eccentrically controls pronation of the foot.
  • Quadriceps contraction turns from eccentric to concentric to bring the femur over the tibia.
  • Hip extensors contract concentrically to produce hip extension throughout loading response.
• Weight bearing: Double support.

Midstance

• Rancho terminology: The point where the entire body weight is over the stance limb and the other foot is off the floor.
• Standard terminology: The point during stance when the entire body weight is directly over the stance limb.
• Muscular actions:
  • Plantar flexors continue eccentrically to control dorsiflexion as the body moves over the stance limb.
  • Quadriceps engage concentrically to continue to produce closed-chain knee extension in midstance.
  • Hip abductors stabilize the pelvis and prevent contralateral hip drop.
  • Iliopsoas eccentrically contracts to control hip extension.
• Weight bearing: Single support (opposite limb is off the ground).

Terminal Stance / Heel Off

• Rancho terminology: Begins when the heel of the stance limb rises and ends when the other foot touches the ground.
• Standard terminology: The point at which the heel of the stance limb leaves the ground.
• Muscular actions:
  • Plantar flexors concentrically aid in propulsion forward.
  • Hip abductors stabilize the pelvis.
  • Iliopsoas continues to eccentrically control hip extension.
• Weight bearing: Single support.

Pre-Swing / Toe Off

• Rancho terminology: Begins when the other foot touches ground and ends when the stance limb reaches toe off.
• Standard terminology: The point in which only the toe of the stance limb remains on the ground.
• Muscular actions:
  • Plantar flexors at peak activity as the foot toes off.
  • Hamstrings begin to produce knee flexion to prepare for swing (body momentum aides this motion).
  • Iliopsoas + other hip flexors begin to work concentrically to produce hip flexion.
• Weight bearing: Double support.

Initial Swing / Acceleration

• Rancho terminology: Begins when stance toe lifts from floor and ends with maximal knee flexion during swing.
• Standard terminology: Begins when toe off is complete and the reference limb swings until positioned directly under the body.
• Muscular actions:
  • Ankle dorsiflexors contract concentrically for foot clearance.
  • Hamstrings assist foot clearance with knee flexion.
  • Hip flexors continue to flex the hip forward.
• Weight bearing: Single support.

Midswing

• Rancho terminology: Begins with maximal knee flexion during swing and ends when tibia is perpendicular to the ground.
• Standard terminology: The point when the swing limb is directly under the body.
• Muscular actions:
  • Ankle dorsiflexors continue to contract concentrically to maintain dorsiflexion.
  • Forward momentum allows for advancement of the limb.
• Weight bearing: Single support.

Terminal Swing / Deceleration

• Rancho terminology: Begins when the tibia is perpendicular to the floor and ends when the heel touches the ground.
• Standard terminology: Begins directly after midswing as the swing limb begins to extend, and ends prior to heel strike.
• Muscular actions:
  • Ankle dorsiflexors contract concentrically to maintain dorsiflexion.
  • Ankle invertors contract concentrically to prepare the foot for contact.
  • Quadriceps contract concentrically to extend the knee for initial contact.
  • Hamstrings act eccentrically to control the rate of knee extension.
  • Hip extensors eccentrically control the rate of hip flexion.
• Weight bearing: Single support.

Gait Cycle and Key Definitions

• Gait cycle: Sequence of motions that occur from initial contact/heel strike of one leg to the next consecutive initial contact/heel strike of that same leg.
• Step length: Distance between successive points of initial contact of opposite feet.
• Stride length: Distance between successive initial contacts of the same foot.
• Step width: Lateral distance between the feet during gait.

Body Kinematics of Gait

• Pelvis movement: Forward-backwards rotation, lateral tilt.
• Trunk: Rotates in the transverse plane opposite to the pelvis.
• Arms: Swing in opposition to contralateral lower extremity.
• Overall: Walking involves coordinated movement of the pelvis, trunk, and upper/lower limbs as a system.

The 6th Vital Sign: Cadence and Velocity

• Cadence: Steps per minute (the number of steps walked in a given period).
• Velocity: Walking speed, typically expressed as meters per minute ( ext{m/min} ) or meters per second ( ext{m/s} ).
• JAMA study (Studenski et al., 2011):
  • Population: 34,485 adults aged 65+.
  • Finding: Gait speed is associated with life expectancy and survival in older adults.
  • Citation: Studenski S, Perera S, Patel K, et al. Gait Speed and Survival in Older Adults. JAMA. 2011;305(1):50–58. doi:10.1001/jama.2010.1923

Functional Outcome Measures in Gait Assessment

• 6-minute Walk Test (6MWT)
• Dynamic Gait Index (DGI)
• Functional Gait Assessment (FGA)
• Ranchos Los Amigos Gait Analysis (RanchoGait App)
• Tinneti (likely a reference to Tinetti Assessment Tool for gait/balance; sometimes called Tinetti Gait Test)

Velocity Categories and Community Ambulation

• Community Ambulator: ~
  • Speed ~ 48 meters/min, ~ 0.8 m/s (typical to cover a football field in about 2 minutes).
• Limited Community Ambulator: ~
  • Speed ~ 24 meters/min, ~ 0.4 m/s (football field in about 4 minutes).
• Household Ambulator: slower than Limited Community Ambulator.
• Practical implication: Lower speeds are associated with reduced community participation and risk of social/physical decline.

Abnormal Gait Patterns (Overview)

• Abnormal gait patterns indicate deviations from normal gait mechanics and often reflect underlying impairments.
• Common patterns include antalgic, ataxic, cirumduction, equine, festinating, Parkinsonian, steppage/foot slap, hemiplegic, scissor, Trendelenburg, and vaulting, among others.

Antalgic Gait

• Definition: Protective gait pattern where stance time is decreased to avoid weight bearing on the involved side due to pain.
• Characteristics:
  • Shorter and rapid swing phase of the unaffected limb.
• Common causes: bone/joint disease, joint inflammation, muscle/tendon/ligament injuries.

Ataxic Gait (Cerebellar)

• Described as staggering and unsteadiness with a wide base of support; often associated with cerebellar disorders.
• Common in: cerebellar diseases (e.g., Arnold-Chiari malformation, vertebrobasilar artery infarctions).
• Features: sway from midline, wide base of support.

Circumduction Gait

• Definition: Circular motion used to advance the leg during swing phase.
• Cause: often due to inadequate hip/knee flexion or dorsiflexion.
• Result: foot clearance is achieved by circumferential hip/leg movement.

Equine Gait

• Characterized by high stepping; excessive activity of gastrocnemius.

Festinating Gait

• Definition: Walks on toes as though pushed; starts slowly and accelerates.
• May continue until patient grasps an object to stop or falls.

Parkinsonian Gait

• Features: forward trunk flexion and knee flexion, shuffling gait with small, quick steps.
• Festinating tendency may occur.

Steppage Gait / Foot Slap

• Features: excessive hip and knee flexion to lift foot high; dorsiflexor weakness leading to foot slap at initial contact.
• Often due to anterior tibialis weakness or dorsiflexion paralysis.

Hemiplegic Gait

• Pattern: involved limb abducted, swings forward around, and lands in front (circumduction-like trajectory).
• Common after cerebrovascular accidents (CVA).

Scissor Gait

• Pattern: legs cross midline with forward progression; spastic pattern.
• Common in children; assistive devices often required.

Trendelenburg Gait

• Cause: gluteus medius weakness on the stance side.
• Features: excessive lateral trunk flexion toward the stance leg, weight shifting over stance phase.

Vaulting Gait

• Pattern: swing leg advances by elevation of the pelvis and plantarflexion of the stance leg.
• Mechanism: hip hiking (elevation of ipsilateral pelvis in the swing phase) to clear the foot.

ROM Requirements for Normal Gait (Range of Motion)

• Normal (degrees) vs Gait (degrees):
  • Pelvis forward & backwards rotation: Normal 0–5°, Gait 0–5°
  • Hip flexion: Normal 0–120°, Gait 0–30°
  • Hip extension: Normal 0–30°, Gait 0–20°
  • Knee flexion: Normal 0–135°, Gait 0–60°
  • Knee extension: Normal 0°, Gait 0°
  • Ankle dorsiflexion: Normal 0–20°, Gait 0–10°
  • Ankle plantarflexion: Normal 0–50°, Gait 0–20°
  • Great toe extension: Normal 0–70°, Gait 0–60°

Ankle & Foot Gait Variations and Impairments

• Foot slap: caused by weak dorsiflexors or dorsiflexor paralysis; leads to toe-down instead of heel strike.
• Toe down instead of heel strike can reflect dorsiflexor weakness or plantar flexor spasticity/contracture.
• Plantar flexor spasticity or contracture can alter heel strike and toe-off dynamics.
• Additional contributing factors: leg length discrepancy, hindfoot pain, clawing of toes, positive support reflex, insufficient dorsiflexion ROM, forefoot/toe pain, weak plantar flexors, weak toe flexors, insufficient plantar flexion ROM.

Knee Gait Deviations

• Exaggerated knee flexion at initial contact: often due to weak quads or quads paralysis; knee flexion spasticity or insufficient extension ROM can contribute.
• Hyperextension in stance: compensations for weak quads; plantar flexor contracture can contribute.
• Excessive flexion with swing: related to knee flexion ROM issues or extensor synergy patterns.
• Quads-related issues: quads extension spasticity or lower limb extensor synergy can alter knee control.

Hip Gait Deviations

• Insufficient hip flexion at initial contact: weak hip flexors or hip flexor paralysis.
• Hip extensor spasticity: alters hip extension and gait timing.
• Circumduction during swing can occur as compensation for weak hip flexors, dorsiflexors, or knee flexors.
• Hip flexion contracture or limited hip extension ROM can contribute to abnormal swing/stance mechanics.
• Compensations include hip hiking during swing, or other extensor synergy patterns.

Reference and Foundational Notes

• Foundational gait science references:
  • Studenski S, Perera S, Patel K, et al. Gait Speed and Survival in Older Adults. JAMA. 2011;305(1):50–58. doi:10.1001/jama.2010.1923
  • Giles, S. (2025). PTA Exam The Complete Study Guide. Scarborough, USA/Maine: Scorebuilders.

Practical Implications for Clinical Practice

• Use gait analysis to identify potential impairments and guide rehabilitation priorities (e.g., targeted dorsiflexor strengthening for drop-foot, hip abductor strengthening for Trendelenburg gait).
• Consider functional outcome measures (6MWT, DGI, FGA, RanchoGait) to track progress.
• Understand how altered gait speed and cadence relate to overall mobility and independence in daily life.
• Recognize that some gait abnormalities may reflect compensations rather than primary deficits; interpret in context of pain, ROM, strength, and neuromuscular control.

Equations and Quantitative References

• Gait cycle definition (formal):
  \text{Gait cycle} = \text{sequence of motions that occur from initial contact/heel strike of one leg to the next consecutive initial contact/heel strike of that same leg}
• Velocity and cadence are primary quantitative gait metrics; value ranges vary by population and context but are central to functional assessment.
• Example velocity category from course content:
  • Community Ambulator: approximately 48\ \text{m/min} = 0.8\ \text{m/s}
  • Limited Community Ambulator: approximately 24\ \text{m/min} = 0.4\ \text{m/s}

Quick Reference: Phase Timeline (Summary)

• Initial Contact / Heel Strike: heel touches ground; dorsiflexion, knee extension, trunk/pelvis stabilization; double support.
• Loading Response / Foot Flat: entire foot contacts ground; weight acceptance; knee flexion controlled eccentrically; tibialis posterior pronation control.
• Midstance: body over stance limb; knee extension; pelvis stabilized; single support.
• Terminal Stance / Heel Off: heel raises; propulsion begins; pelvis stability maintained; hip extension control.
• Pre-Swing / Toe Off: toe-off; rapid knee flexion and hip flexion to prepare for swing; double support.
• Initial Swing / Acceleration: toe off complete; limb clears ground; hip/knee flexion; single support.
• Midswing: limb under body; continued dorsiflexion; momentum drives progression; single support.
• Terminal Swing / Deceleration: limb decelerates in preparation for heel strike; knee extension to initial contact; single support.

Note on Using These Notes

• Use this as a replacement study guide for PTA 108 gait content.
• Cross-check with practical gait observations and patient-specific ROM and strength data for clinical decision making.
• If needed, convert any section into flashcards for rapid recall during exams.