Equilibrium%20Point%20Hypothesis%20(EPH)

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Equilibrium Point Hypothesis(EPH)
Feldman (1966, 1986, ) ?-Model Bizzi (1978,
1979, ) a- Model
?F0 ?? ???? ?????
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EPH and Muscle Stiffness
F k ( X X0) ????? ?? ??? (????)
K s (a ) X0 ß (?)
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Load Effect
ßv Tf - Td/s
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Evidence for EPH (Polit Bizzi 1978-9)
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EPH Generalization
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Questions Unanswered?
1- Role of Motor Centers in the Brain? 2- Motor
Learning? 3- Environmental Effects?
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Fitts Law Speed-Accuracy Trade-off
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Fitts Law Speed-Accuracy Trade-off
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Fitts Law (cont.)

• MT a b log2 (2A/W)
• MT Movement Time
• ID ( Index of Difficulty) A/W
• log2 Inspired from information theory

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Fitts Law (cont.)
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Fitts Law (cont.)

• Larger limb showed
• more sensitivity

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Learning Fitts Law (cont.)Kelso (1984)

• Slope was reduced to nearly zero following 40,000
  trials.

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Aging Fitts Law (cont.)Kelso (1984)

• Aging increases the slope

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Modification to the Fitts Law

• MT a (A/W)b
• Modification effect is minor (10)

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