lecture 4

Question 1

what are the ways that we can assess balance?

Answer 1

Kinetics: Forces under the feet.

EMG: Muscle activity.

Kinematics: Body movement in space.

Question 2

what is posturography?

Answer 2

Objective measures of postural control in static and dynamic conditions.

Question 3

how do we measure posturography?

Answer 3

body kinematics, dynamics, and muscle activation patterns.

Question 4

what is static posturography?

Answer 4

characterizes the performance of the postural control system by
measuring postural responses when in a static position

Question 5

what is dynamic posturography?

Answer 5

characterizes the performance of the postural control system by
measuring postural responses to an internal or external perturbation

Question 6

during quiet stance, what happens to COM?

Answer 6

remains the same

Question 7

how is sway modeled for quiet stance? (Physics)

Answer 7

as an inverted pendulum that rotates around the ankle

Question 8

during quiet stance, how is the movement of the COM controlled?

Answer 8

ankle torque

Question 9

how is static posturography measured?

kinematics

Answer 9

• position
• velocity
• acceleration
• timing

Question 10

how do we measure kinematic measures for posturography?

Answer 10

motion capture

Question 11

what can motion capture inform us about?

Answer 11

COM can be calculated using relative locations of body segments

Question 12

what kind of kinetic measures are taken for posturography?

Answer 12

moments generated and ground reaction forces

Question 13

define center of pressure COP

Answer 13

point location of the weighted average of the sum of vertical ground reaction forces

Question 14

how is COM different from COP?

Answer 14

• COP acts to control the body centre of mass (COM) COP is the controller
• COP moves rapidly ahead and then behind the COM to keep it in a more central position
• COM is the controlled variable
• COP represents slow COM shifts, and faster adjustments by the CNS that correct COM movement