AMBULATION

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AMBULATION GAIT

• Human Gross Anatomy
• David G. Greathouse, PhD, PT, ECS
• November 2, 2004

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Objectives

• Define and describe the components of the gait
  cycle.
• Describe the kinematics of the pelvis, hip, knee
  and ankle during the gait cycle.
• Describe the muscular activity and actions
  produced by the muscles of the LE during gait.
• Discuss the pathokinesiology of the following
  gait impairments Gluteus medius muscle
  weakness, anterior leg compartment syndrome
  (foot drop), posterior leg compartment
  syndrome, and antalgic patterns - lower extremity
  and trunk-spine.

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Gait

• Normal human gait repeats a basic sequence of
  limb motions that serve to progress the body
  along a desired path while maintaining
  weight-bearing stability, conserving energy, and
  absorbing the shock of floor impact.

Rancho Los Amigos National Rehab Center
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Gait - Definitions

• Gait - manner or style of walking
• Gait cycle beginning of a walking event by one
  limb and continuing until the event is repeated
  again with the same limb
• time from heel strike to the next ipsilateral
  heel strike
• Stride - one complete gait cycle
• Step - beginning of an event by one limb until
  the beginning of the same event with the
  contralateral limb

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Phases of Gait Cycle
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Gait Cycle

• Swing phase - during the walking cycle, a given
  foot is in the air, toe-off to heel stride, 38
  (ordinary walking)
• Stance phase - during a walking cycle, a given
  foot is in contact with the ground, heel-strike
  to toe-off, 62 (ordinary walking)

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Definitions (cont)

• Duration of the gait cycle - for any one limb
  extends from the time the heel contacts the
  ground until the same heel contacts the ground
  again
• Heel-strike (HS) or heel-on - heel contacts the
  ground
• Toe-off (TO) - toes leaving the ground

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Definitions (cont)

• Speed of locomotion - steps per minute or meters
  per second
• Cadence - number of steps completed per unit of
  time (steps/min)
• Typical gait cycle - 1 to 2 seconds (82 m/min,
  113 steps/min, 3 miles/hr)
• Double support - both limbs are in stance phase
  at the same time

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Eccentric Contraction

• Muscles operate eccentrically to either dissipate
  energy for decelerating the body or to store
  elastic recoil energy for a shortening
  (concentric) contraction.

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Running

• Double support no longer present
• Both feet off ground for brief time

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Subphases Stance Phase

• Initial Contact (IC)
• The moment when the foot contacts the ground,
  heel strike (heel strike)
• Loading response (LR)
• The weight is rapidly transferred onto the
  outstretched limb, the first period of
  double-limb support (foot flat)
• Midstance (MSt)
• The body progresses over a single, stable limb
• Terminal Stance (TSt)
• Progression over the stance limb continues. The
  body moves ahead of the limb and weight is
  transferred onto the forefoot
• Pre-Swing (PSw)
• A rapid unloading of the limb occurs as weight is
  transferred onto the forefoot (toe-off)

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Subphases of Swing Phase

• Initial swing (ISw)
• The thigh begins to advance as the foot comes up
  from the floor.
• Midswing (MSw)
• The thigh continues to advance as the knee begins
  to extend the foot clears the ground.
• Terminal Swing (TSw)
• The knee extends the limb prepares to contact
  the ground for Initial Contact.

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Gait Cycle
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Gait Cycle Functional Tasks

• Weight Acceptance (WA)
• This is the period when weight is rapidly loaded
  on the outstretched limb. The impact of the
  floor-reaction force is absorbed and the body
  continues in a forward path while stability is
  maintained. (Initial Contact and Loading
  Response)
• Single Limb Support (SLS)
• Is the period when the body progresses over a
  single, stable limb. Weight is transferred onto
  the metatarsal heads and the heel comes off the
  ground. (Mid Stance and Terminal Stance)
• Swing Limb Advancement (SLA)
• Is the time when the limb is unloaded and the
  foot comes off the ground. The limb is moved
  from behind to in front of the body, reaching to
  take the next step. (Pre-Swing, Initial Swing,
  Mid Swing and Terminal Swing)

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Phases
Function
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Kinematics of the Gait Cycle

• A Sagittal plane
• B Frontal plane
• C Horizontal plane

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Muscle Activity in the Gait Cycle
HS FF HO TO
Eccentric Concentric
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Muscle Activity in the Gait Cycle

• Pretibial Muscles
• Anterior tibial, EDL, EHL
• Prior to and during heel strike
• Eccentric contraction - lowers foot to the ground
• Prior to and during preswing
• Concentric contraction DF foot, clear toes off
  ground
• Calf Muscles
• Gastrocs, Soleus (FDL, FHL, Posterior tibial)
• Foot flat
• Eccentric contraction - control of tibia over the
  foot
• Heel off
• Concentric contraction ankle plantarflexion

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Muscle Activity in the Gait Cycle

• Quadriceps
• Vastus medialis/lateralis/intermedius, RF
• Before Heel Strike
• Concentric contraction initiate knee extension
• Swing phase
• Eccentric contraction slow down leg (tibia)
• Hamstrings
• Biceps, Semitendinosus, Semimembranosus
• Heel strike
• Eccentric contraction - HS peaks protects knee
  from hyperextension
• Swing phase
• Concentric contraction knee flexion, hip
  extension

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Muscle Activity in the Gait Cycle

• Hip Abductors
• Gluteus medius, Gluteus minimus, TFL
• Stance phase
• Concentric contraction - stabilize pelvis
• Hip Adductors
• Adductor longus/brevis, Gracilis, Adductor magnus
  (horizontal and vertical heads)
• Early and late stance
• Concentric contraction stabilize pelvis

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Muscle Activity in the Gait Cycle

• Gluteus Maximus
• Stance phase
• Eccentric contraction decelerate forward
  momentum
• Pre-Swing phase
• Concentric contraction hip extension
• Erector Spinae
• Heel strike through Toe-off
• Maintain trunk posture

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Muscle Activity in the Gait Cycle

• Fibularis longus and brevis
• Stance phase
• Concentric contraction maintain medial and
  lateral stability of the foot
• Foot Intrinsics
• Stance phase
• Concentric contraction support plantar fascia

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Gluteus Medius Muscle Weakness

• Etiology - L4/L5/S1, Sup gluteal n, polio,
  post-surgery, amputee (prosthetics)
• Support effect of muscle on pelvis is lost
• Right gluteus medius muscle out
• Stance phase on RLE - Left pelvis drops
  (Trendelenberg - uncompensated)
• Compensated - trunk laterally leans to R
• Circumduction leg swings in arc fashion

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Anterior Leg Compartment Weakness

• Foot drop
• Etiology - L4/L5/S1, Common or Deep Fibular
  (Peroneal) nerve - Dislocation of fibular head,
  Ant compartment syndrome, SLWC tight
• Loss of DF of foot
• High stepping gait, foot slap

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Posterior Compartment of the Leg Weakness

• Etiology - Tibial n injury, L5/S1/S2
• Paralysis of PF of the foot or intrinsics
• Unable to PF foot or flex toes, no toe-off

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Antalgic Patterns of the LE

• Ortho or musculoskeletal dysfunctions
• Pain in any or all joints in the LE
• Changes in gait kinematics, stride parameters,
  and temporal sequencing
• Rate of loading will be decreased - Partial
  Weight Bearing
• OA of the hip, knee joint injury, ankle injury

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Antalgic Patterns of the Trunk

• HNP
• Forward bend (Flex) - Backward bend (Ext)
• Sidebending - lateral bending

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QUESTIONS ?