Action Side Of The Game 4 Flashcards
What is the precontact phase
And grip and lift phase
Getting hand to object
Begin to apply forces through finger tips to lift object
Show how brain organises movements
What did John Roe suggest the fundamental concept was
Pre contact phase and transport phase
Brain controls wrist, and the opening and closing of the grip action
What did ellie brainer suggest
Brain controlling tip of thumb and index finger individually
But brain cannot control 2 anatomical systems if they are linked
What are the true fundamental concepts (3)
Transport- placing hands in position
Grasp- formation of appropriate aperture size
Rotation- forming appropriate orientation
What are the 3 elements to object vector
Grasping needs to match the vector formed between the thumb and the index finger
Need to transport the origin from where the thumb is located to the origin of the vector
Open gap in fingers and close to fix object into grasp
Origin: tip of thumb/index finger depending on object size
What does Optotrak do?
Measures reach and grasp sing infra red emitting diodes
Put infra red markers on thumb, index, wrist and ask p’s to reach and grasp
See there the markers have been in 3d space
Measure speed, acceleration, smoothness
What does Optotrak show about the transport phase
Each one is precisely tailored to object
Straight lines in movement- interesting because of joints don’t allow us to move out arm straight
What is grip force
Index finger starts to increase force, then thumb begins ms later, increases to peak
Adjusted in parallel and scaled to a target force
Based on visual and tactile cues, and memory representation
What is load force
Increase to peak before coming down
Load force is only applied once an object is secure
What did Piaget 1954 find
Reaching and grasping is the fundamental ability to begin to progress and develop
