Ambulation and Aids

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Ambulation and Aids

• CHAPTER 12

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Locomtion

• Method used to move from one place to another
• Normal gait has similarities
• Differences from
• Postural variation
• Weaknesses
• Structural abnormalities
• Soft tissue length alterations

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Gait cycle

• Stance phase
• Foot is in contact with ground
• 60-62 of gait cycle
• Fist and last 10 of phase is in double limb
  support
• Phases
• Heel strike
• Foot flat
• Mid-stance
• Heel off
• Toe off

• Swing phase
• Foot is not weight bearing
• 38-40 of gait cycle
• Phases
• Early swing (acceleration)
• Mid-swing
• Late swing (deceleration)

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Stride terminology

• Stride length heel strike to heel strike on
  same foot
• Step length heel strike on one foot to heel
  strike of other foot
• Stride width midline of one foot at mid-stance
  to other foot
• Large variation in walking rate

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COG pathway

• COG movement kept to minimum by
• Multi-joint system
• Controlling force/momentum
• Absorption of shock/impact
• Movement is sinusoidal in nature
• Wheels would be better than legs!

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Gait determinants (link)

• Pelvic rotation 4? toward stepping leg
• Pelvic tilt 4- 5? in down in mid-stance toward
  swing leg
• Knee flexion extended at heel strike, but
  flexes 15? by mid-stance
• Ankle motion its COG is highest when knee COG is
  lowest to smooth curve
• Lateral pelvic motion shifts COG over support
  leg max shift at mid-stance

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Gait kinematics (joints)

• Trunk and upper extremities
• Trunk movement coordinated with pelvis
• Trunk rotates opposite of pelvis
• Arm swing assists trunk rotation
• Pelvis 4? A/P tilt, 8? lateral tilt, and 8?
  rotation
• Hip 43? flex/ext, 13? ab/add and 8? rotation
• Knee 60? flexion and 18? tibial rotation
• Ankle foot and ankle work together to absorb
  shock and balance over uneven ground

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Gait kinetics (muscles)

• Create (concentric), decelerate (eccentric), and
  stabilize (isometric) motion
• Cyclic activity with rest periods
• More energy needed in stance phase than swing
• Acceleration and deceleration require most
• Shock absorbers quads and foot extensors work
  eccentrically
• Stabilizers hip extensors and torso muscles keep
  trunk erect and prevent excessive pelvic tilt
• Accelerators posterior calf muscles and ankle
  inverters/everters
• Decelerators hamstrings work eccentrically in
  swing and concentric in early stance

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Ground reaction forces

• Shear occurs A/P and M/L
• Initial contact force is forward, but reverses
  after mid-stance
• Shortening stride length reduces A/P shear
• M/L shear occurs as weight is transferred forward
  on foot
• Greatest vertical force at toe off most in
  double support

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Pathological gait (link)

• Results from injury, weakness, loss of ROM, pain,
  bad habits
• Look at
• Stride length
• Stride width
• Cadence
• Trunk lean
• Arm swing
• Also observe
• Head position
• Shoulder vs. hip alignment
• Foot/heel positions

• Gluteus medius gait trunk laterally over weak
  hip
• Quadriceps gait knee kept extended through
  stance phase (lurch!)
• Ankle tightness reduced dorsiflexion hip
  hiking common
• Painful knee shorten or circumducted stride
  increased flex at mid-stance and decreased during
  swing

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Normal running gait

• Mechanics affected by??
• Running stride toe off on one foot to toe off
  on other
• Running cycle two running strides
• Stride length and cadence increase with velocity
• Ground reaction force increases with speed
• Softer surfaces eliminate peak impact
• Single vs. double impact

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Normal running gait

• Stance phase shorter
• Swing phase longer
• No double-support
• Nonsupport phase (float)
• COG lowers as speed increases
• Hip and knee never fully extend
• Faster runners land on midfoot (slower on
  rearfoot)
• Trunk lean increases from 4? to 7? to 11.6?

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Assistive devices

• Fitting crutches and cane
• Gait patterns
• Tripod/swing NWB
• Three-point PWB to FWB
• Four-point FWB
• Single support
• Up-stairs
• Down-stairs
• Ramps
• Transfers

• Precautions
• Check equipment
• Environmental factors
• Dont be an obstacle!
• Crutch palsy