Transport in R&G

• Transport Phase:

  • consists of 2 main components:
  • acceleration
  • deceleration
• Transport Phase:

  1. Hand starts opening at the start of the transport phase
  2. Fast, moves the hand to the vicinity of the object
  3. Aperture increases throughout the acceleration phase
  4. Aperture decreases during the deceleration phase
  5. Distance between thumb and index finger reflects object size/shape (grip formation)
  6. Trajectory determined by the relative position of the target & hand
• Changes in grip size to object:

  • The size of maximal grip opening is proportional to the size of the object
• Once the hand contacts the object further guidance is provided by what?

  • feedback from cutaneous sensation and proprioception
• Velocity dependent on nature of task

  A) small object

  B) big object

  
• Changes in grip size to object:

  • The size of maximal grip opening is proportional to the size of the object
  • 2 different subjects shown here (cylinder 55 mm diameter and rod 2 mm diameter), note different grip sizes but similar curve shapes
  • just because someone can pick up a small object, doesnt mean they can pick up a big object