What is posture

• What is posture?

  • No universal definition of posture but broadly accepted as:
  • Biomechanical alignment of body segments relative to gravity i.e flexed, rotated etc
  • or
  • The way in which someone usually holds their shoulders, neck, and back, or a particular position in which someone stands, sits etc
• Posture is NOT static:

  • Posture is part of a dynamic system for the achievement of function - mobile stability
  • Think of Posture as ‘arrested movement’ i.e. it is an active process
• “Ideal” stacking of segments - Line of gravity (“balance point” of body):

  • Through mastoid process of ear
  • Through or just anterior to shoulder joint
  • Just posterior to hip joint/ through greater trochanter
  • Just anterior to the knee joint
  • Just anterior to ankle joint

  
• Key message

  • We have an inherent ability to move in and out of different postures
  • Variation in posture is ‘normal’
  • Our ‘starting posture’ shapes future movement i.e. flexed trunk for STS
• Relationship - Balance & Posture: (some highlighted words are acronyms)

  • The upright human body has a relatively high CoG & a relatively small BoS
  • Balance disturbances (perturbations) can be generated internally (i.e. from inside the body reaching, stepping) or externally (i.e. from outside the body i.e. a push, trip, slip)
  • Balance and posture come together as a complex motor skill from interaction of multiple sensorimotor processes - postural control
• Line of gravity - anterior view:

  • midline of nose
  • midline of sternum
  • umbilicus
  • symphysis pubis