EMG

Question 1

What is EMG measuring?

Answer 1

motor unit recruitment

Question 2

What is the amplitude of EMG signal measuring?

Answer 2

reflects the size, number, and distance of active motor units from recording electrodes.

Question 3

What kind of force is EMG measuring?

Answer 3

isometric

Question 4

Is EMG local or global?

Answer 4

local

Question 5

Will eccentric or isometric contraction create a larger EMG signal? Why?

Answer 5

Isometric

While eccentric contraction is stronger, it won’t require you to create as many motor units in any one instant.

Question 6

What will a larger distance between electrodes do to specificity of EMG recording?

Answer 6

Larger distance=less specificity

Question 7

What electrode factors can alter an EMG signal?

Answer 7

size 
distance between electrodes
distance from muscle monitoring
movement
relationship to other muscles (cross-talk)
quality of electrode
skin quality

Question 8

What can you alter on the EMG machine to measure a weak muscle?

Answer 8

Amplitude, measures sensitivity

Question 9

What is a greater sensitivity on an EMG-1-800 or 1-30?

Answer 9

1-30

Question 10

How many electrodes do you need in an EMG? Why?

Answer 10

3.

2 record while one grounds