Performance and Motor Control Characteristics of Functional Skills Chapter 7

When both speed and accuracy are essential to perform the skill,

Accuracy is reduced and vice-versa

Paul Fitts (1954) showed we could mathematically predict movement time for speed – accuracy skills

Movement distance Targer size

MT = a + b log2 (2D/W) As target gets smaller movement time gets bigger

Both tasks have equal difficulty then movement time will be equal for both task

The more difficult the tas, the more dificult tasks reuire more movement time

So does the movement time which means movement time will be slower for a taker with a higher ID

Important motor control question concerns the spatial – temporal relationship between the transport and grasp components Initial views proposed the independence of the components

Open loop controlClosed loop control

– At movement initiation Initial movement instructions sufficient to move limb to the vicinity of the target

– At movement termination Feedback from vision and proprioception needed at end of movement to ensure hitting target accurately

Actions involving reaching for and grasping of objects

TransportGraspObject manipulation

Movement of the hand to the object