Lecture 14: CIS

Question 1

change in support strategies are distinguished by _____

Answer 1

presence of limb movements to alter the BOS to produce a new stable state

Question 2

Change in support strategy depends on___

Answer 2

options afforded by the environment

Question 3

Why are change in support strategies important

Answer 3

vital role in preventing falls
can provide much greater stability (BOS can be rapidly expanded)
only option for responding to very large perturbations

Question 4

Change in support strategies can be ___

Answer 4

very complex
account for unpredictable body movement, constraints on limb movement imposed by environment

Question 5

If subjects are allowed to respond naturally, the CIS reactions are often____

Answer 5

initiated early and even in response to smaller perturbations(as long as option is viable/allowed)

Question 6

What did maki and mcllroy study and find

Answer 6

studied fixed support vs change-in support strategies
try not to step vs allowed to step
see last resort step reaction, but also used even with smaller perturbations

Question 7

When unconstrained, step reactions are ____ ___ than voluntary step movement

Answer 7

much faster

Question 8

Instructions to avoid stepping, ensures the step response is _____

Answer 8

only used as a later option
onset latency similar to voluntary

Question 9

step likelihood depends on ____ at time of perturbation

Answer 9

COP location
shown by Tokuno et. al.

if the perturbation is in the opposite direction to the COP, it sends the COM towards the COP

Question 10

Results of Tokuno et al in stepping responses

Answer 10

more steps for forward perturbations
more steps with COP OPPOSIDE TO PERTUBATION DIRECTION

Question 11

In young healthy subjects, step responses usually only involve ______

Answer 11

a single step, almost always a crossover step (karaoke)

Question 12

for lateral perturbations, the step food is almost always ______

Answer 12

the foot unloaded by the perturbation

Question 13

On rare occasions when the foot loaded by the perturbation initiates the step, the subject has ______

Answer 13

pre-planned to step with that leg in advance, shuffle step

Question 14

In voluntary stepping, the APA almost always ____

Answer 14

precedes the step to move COM over stance leg to ensure lateral balance

Question 15

In compensatory forward stepping, the APA is either ____

Answer 15

totally absent or minimal, leading to a large lateral destabilizing moment toward the swing leg
needs to be corrected for after foot contact

Question 16

during perturbations, the physical constraints of a cane/walker can alter ____

Answer 16

normal stepping response pattern
frequency of collisions with objects

Question 17

preferred stepping leg depends on ____ and _____

Answer 17

load and constraints

Question 18

T/F Preferred stepping leg was related to the dominant leg

Answer 18

false

Question 19

when the non preferred leg is obstructed, ________ stepping in preferred limb ______

Answer 19

more frequent, even when loaded
however, step direction is altered (more lateral, less forward)