Chapter 7 Flashcards
manual aiming skills
motor skills that involve arm, hand, and/or finger movement to a target;
speed-accuracy trade-off
a characteristic of motor skill performance in which the speed at which a skill is performed is influenced by movement accuracy demands; the trade-off is that increasing speed yields decreasing accuracy, and vice versa
Fitts’ law
a human performance law specifying the movement time for an aiming movement when the distance to move and the large size are known.
index of difficulty (ID)
according to Fitts’ law, a quantitative measure of the difficulty of performing a skill involving both speed and accuracy requirements;
prehension
action of reaching for and grasping an object the may be stationary or moving
motor equivalence
the capability of the motor control system to enable a person to achieve an action goal in a variety of situations and conditions (writing your signature with either hand)
adapt to various context demands
bimanual coordination
a motor skill that requires the simultaneous use of the 2 arms
skill may require the 2 arms to move with the same or different spatial and/or temporal characteristics
speed and accuracy have what type of a relationship
indirect,
trade-off between emphasizing one over the other
open-loop control
immediate reaction, no feedback taken into consideration
speed
closed-loop control
takes feedback into consideration (proprioceptive, visual, etc)
(accuracy)
3 phases of visual movement
preparation, initial flight, termination
preparation phase
assess regulatory conditions of environmental context
initial flight phase
monitor limb displacement and velocity
shift gaze to keyhole at 50% time-to-contact
termination phase
provide spatial-temporal info to correct movement accuracy error to ensure insertion of key
Transport
Movement of the hand to the object
Grasp
The hand taking hold of the object
Object manipulation
The hand carrying out the intended use for the object
relationship between reach/transport and grasp
strong temporal relationship
components interact synergistically
pre-hension phases
transport, grasp, object manipulation
coordinative structures
muscles and joints needed to be able to perform an action (ex. handwriting)
role of vision in pre-hension
prepare and initiate movement (assess regulatory conditions)
transport of hand to object
grasp of object
asymmetric bimanual coordination
using both arms, but in different directions
symmetric bimanual coordination
using both arms in the same directions
Experiment by Wiliams and McCrirrie (catching a ball)
successful ball catchers initiated final hand and finger shape 80 sec earlier than non-catchers
central pattern generators (CPG)
located in the spinal cord; involved in the control of locomotion (i.e. gait)
basis for stereotypic rhythmicity of walking and running gait patterns
