Gait lecture

Nerve Tension Testing – “The Slump”

  • Goal: determine whether neural tissue, not muscle or joint, is the pain generator.
  • Test position
    • Patient slumps (thoracic & lumbar flexion → maximal dural lengthening).
    • Cervical flexion is usually added last to avoid early cord irritation.
    • If still equivocal, side-bending is layered on:
    • Side-bend toward symptomatic side ↓ neural tension → often ↓ symptoms (provides slack).
    • Side-bend away lengthens ipsilateral neural tissue → ↑ symptoms if nerve is involved.
  • Rationale
    • Nervous system behaves like an elastic, continuous “telescope.”
    • Side-bending R → L neural tract lengthens, R tract shortens.
    • Clinically mimics daily movements that put nerves on stretch (e.g., tie shoes, reach forward).
  • Sensory confirmation
    • Assess dermatomal changes via sharp/dull, light touch, proprioception where indicated.

Lumbo-Pelvic & Hip Lever Arms

  • Picking an object off floor with knees straight:
    • Legs form a very long lever arm on pelvis.
    • Rectus femoris & iliopsoas are also placed on maximal length.
    • Added torque (τ=r×F\tau = r \times F) ↑ anterior-hip & pubic stress → pain when inflamed.
  • Clinical pearl
    • Teach patients to bend the knees (shorten lever) or stagger stance to reduce lumbar & hip load.

Common Trauma Mechanism – Weightlifters

  • Cause: improper hand/bar position during the final pull of Olympic lifts.
    • Bar collides with pubic symphysis (“hip bump”).
    • Repeated micro-impact → synphyseal inflammation, pain with coughing, sit-ups or adductor squeeze.

Sacro-Iliac Joint (SIJ) – Form Closure

  • “Form closure” = intrinsic bony architecture that passively stabilises a joint.
    • SIJ relies on inter-locking ridges & grooves of sacrum & ilium.
    • Stability is referenced from the base (superior surface) of the sacrum.
  • Nutation/Counternutation
    • Nutation = sacral base tips anteriorly; enhances form closure.
    • Counternutation = posterior tipping; reduces passive locking, needs more muscular (“force”) closure.

Gait Cycle Nomenclature (Newman vs Running)

  • Newman (textbook) – Walking
    • Stance: initial contact (heel-strike) → loading response → mid-stance → terminal stance → pre-swing.
    • Swing: initial swing → mid-swing → terminal swing.
  • Running terms (acceleration, mid-swing, deceleration) ≠ Newman.
    • Use running labels ONLY for running analysis.
  • “Foot flat” sometimes colloquially called “foot flop.”

Body Height & Gravity

  • Lecturer’s reminder: gravity aids forward fall from ~6 ft height.
    • Potential energy PE=mghPE = mgh converts to forward momentum when COM passes BOS.

Energy Storage & Return at Terminal Stance (Push-Off)

  • At terminal stance
    • Hip is extending; anterior structures (iliopsoas, fascia) are eccentrically stretched (like a band).
    • Elastic recoil + concentric glute activation generate propulsion with minimal metabolic cost.
  • Teaching faster walking
    • Emphasise push-off quality → train terminal stance mechanics.
    • Cue “stretch then spring” rather than just hip-flexor power.

Pelvic Kinematics – Naming & Clinical Testing

  • Pelvic motion is always named off the stance (reference) leg.
    • Example: Right leg stance; contralateral pelvis drops → called right hip drop (Trendelenburg).
    • Muscle to test = right gluteus medius (ipsilateral to stance leg).
  • Frontal-plane force couple
    • Gluteus medius (stance side) ↓ pelvic drop.
    • Contralateral Quadratus Lumborum (QL) hikes opposite iliac crest.

Phase-Specific Muscle Roles

  • Weight Acceptance (initial contact → loading response)
    • Look for muscles working eccentrically to absorb shock (e.g., quadriceps, dorsiflexors).
  • Single-Leg Support (mid-stance)
    • Muscles act isometrically to keep COM stacked (hip abductors, core stabilisers).
  • Push-Off / Propulsion (terminal stance → pre-swing)
    • Key muscles fire concentrically (gastroc-soleus, glute max) to accelerate COM forward.

Quick Clinical Algorithms

  • Pelvic drop → suspect weak stance-side glute med.
  • Pain on straight-leg forward bend & leg raise → consider rectus/psoas strain or inflamed pubic symphysis.
  • Pain ↗ when side-bending away in slump → neural tension positive.

Key Takeaways

  • Use slump + side-bend to differentiate neural vs musculoskeletal pain.
  • SIJ stability stems from form closure (shape) plus force closure (muscle/fascia).
  • Long lever arms magnify force; modify lifts & daily moves accordingly.
  • Gait analysis demands phase-correct terminology; walking ≠ running labels.
  • Enhance walking speed by optimising terminal stance energy return.
  • Frontal-plane pelvic control depends on glute med ↔ contralateral QL force couple.