Lecture 12 Flashcards
Deceleration influences
muscle activity
When deceleration is expected…
there is reduced muscle activity
When deceleration is unexpected
excessive muscle activity is seen
initial balance correcting response to deceleration is seen when randomized
postural response amplitudes decreased with loss of…
Vision
Vestibular Input
Proprioceptive input
less amplitude in balance correcting muscle seen in those with loss
Stretch responses may be ____ over ____ trials if ______
augmented, repeated, stabilizing
see a longer amplitude after multiple trials if the stretch reflex helps the balance response
What did carpenter et. al. study in stolkholm?
Difference in interval timing during balance pertubations
short (100ms) long (2000ms)
10 forwards and backwards pertubations
What were the results from Carpenter et. al. (2005)
Inverted pendulum strategy seen in short pertubation
more hip and ankle strategy seen, much longer balance response
Deceleration may elicit ____ ____ that are ____ to the initial acceleration
muscle responses
unrelated
subjects may learn to utilize the ____ effects of the ____-
stabilizing
deceleration
Mcllroy and Maki, 1994
What did cresswell et. al. study in 1994
pertubations to upper body
used a vest with weights on back and front
can deactivate weight with electromagnet, observed
When Rietdyk et al in 1999 studied upper body pertubations, what did they find
- upper body pertubation, ankle and hip strategies were used, going the same direction like inverted pendulum
- when pertubation was applied to COM, see a secondary response for the hip to counteract the displacement
- same control of COM displacement seen in both
Upper body pertubations responses are ____ to translations
similar
Upper body pertubation responses involves____
both lower and trunk muscles
Upper body pertubation responses are ___ ____
directionally dependant
