KIN 221 - Module D6 Assessing Risk

tremor

motor units start to fire synchronously causing a ____________

increase activation

the first sign of fatigue is when the motor units ____________

fire synchronously

the second sign of fatigue is when the motor units _____________

drop out

the last sign of fatigue is when the motor units ___________

true

to check the decrease in amplitude during fatigue, we can use the RMS to see changes over time

\
t or f

false

to check the decrease in amplitude during fatigue, we can use the average EMG to see changes over time

\
t or f

true

mean/median power frequencies will shift to lower frequencies during fatigue

\
t or f

45%

there is a ______ drop in the MdPF which we can use as a threshold to detect fatigue

gaps

_______ indicate periods of muscular rest

high

a ____ number of gaps will cause a decrease risk in injury

low

a _____ number of gaps will cause an increased risk of injury

true

a gap is defined as a portion of EMG below the amplitude of 0.5%MVC for more than 0.2 seconds

false

few gaps will decrease the likelihood of pain

\
t or f

APDF/amplitude probability distribution function

helps determine exposure levels for prolonged muscular activity

true

a APDF is done on a normalized linear enveloped data

\
t or f

probability levels

_________________ tell us the percentage of time spent with muscle activity at/below certain MVC%

static contraction level

if p=0.1, then it is a ________________

median contraction level

if p=0.5 then it is a ___________________

maximum contraction level

if p=0.9 then it is a -_________________

LE normalized curve

the first step of making a APDF is to use a ______________

histogram

the second step of making a APDF is making a __________

false

the histogram can have values that go below 0

\
t or f

plot probability for MVC

the last step for making a APDF is to

true

the find the probability for each MVC, you need to add up each data point (and everything below it) then divide by total points

\
t or f

2-5

the concern zone for static contraction level is ______ %MVC

10-14

the concern zone for median contraction levels is _____ %MVC

50-70

the concern zone for maximal contraction levels is ____%MVC

2\.3x

working above the shoulder for more 6-9% and more of the time causes you to be _____ more likely to get hurt

2\.02x

working 45 deg elevated from the trunk more than 15% of the time causes you to be _________ more likely to be hurt

true

EMG is used to estimate muscle force and thus estimation of joint contact forces

\
t or f