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Mod 3 - Understanding Gait Cycle and Terminology

Aug 11, 2024

Lecture on Gait Cycle and Terminologies

Key Terminologies

  • Step Length: Distance between the two different legs (right heel to left heel).
  • Stride Length: Distance between the same leg (heel of one foot to the next heel of the same foot on the ground).
  • Step Width: Distance from the center of one leg to the other leg; important for representing the base of support.

Gait Cycle

  • Divided into two phases:
    • Stance Phase
    • Swing Phase

Stance Phase

  1. Heel Strike (Initial Contact)

    • Body weight begins to shift over to the stance limb.
    • Hip: 20° flexion, Knee: 5° flexion, Ankle: 0° dorsiflexion.

  2. Loading Response (Foot Flat)

    • Stance leg starts taking body weight, knee absorbs shock.
    • Hip: 20° flexion, Knee: significant role in shock absorption (eccentric contraction of quadriceps).
    • Ankle: Moves from dorsiflexion to plantarflexion.

  3. Mid Stance

    • Body weight fully shifts to stance limb.
    • Hip: neutral, Knee: slightly flexed, Ankle: controls falling forward (eccentric contraction of plantarflexors).

  4. Terminal Stance (Heel Off)

    • Body weight shifts from stance limb to the other leg.
    • Hip: 20° extension, Knee: 5° flexion, Ankle: 10° dorsiflexion.

  5. Pre Swing (Toe Off)

    • Emphasis on ankle to clear foot from the ground.
    • Ankle: plantarflexor push off.
    • Knee: flexion due to plantarflexor activity.

Swing Phase

  1. Initial Swing

    • Goal: Raise leg and move forward.
    • Ankle: dorsiflexion from 15° plantarflexion to 5°, Knee: 40° flexion.

  2. Mid Swing

    • Swing leg moves forward.
    • Knee flexors (hamstrings) contract eccentrically to prepare for landing.

  3. Terminal Swing

    • Slow down for safe landing.
    • Hamstrings play a key role.

Gait Patterns

  • Step-to-Gait: Step right foot out, left matches to same level.
  • Step-through-Gait: Step left out, right passes it.

Crutch Use and Gait Patterns

  • Four-Point Gait: Four points of contact (two crutches, two legs).
  • Three-Point Gait: Three points of contact (one leg, two crutches).
  • Two-Point Gait: Two points of contact (both crutches, one leg).

Weight-Bearing Terminology

  • NWB (Non-Weight Bearing): No weight on limb.
  • Partial Weight Bearing: Tolerates partial weight.
  • Full Weight Bearing: Full weight is tolerated.

Deviations in Gait Patterns

  • Scissor Gait: Seen in cerebral palsy due to tight hip adductors.
  • Hemiplegic Gait: Common in post-stroke patients due to one side weakness.
  • Shuffling (Parkinsonian) Gait: Forward lean and rapid, short steps seen in Parkinson's disease.
  • Vaulting Gait: Compensatory mechanism, often due to knee fusion causing stance leg to rise.
  • Cane Use on Stairs: Unaffected leg first when ascending, affected leg first when descending.

Understanding these concepts is vital for analyzing and treating gait abnormalities in clinical practice. There are extensive resources and books for further in-depth study on gait analysis.

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