(S1W2) Control of Muscle Activation part 8

Question 1

What is another name for a H-reflex?

Answer 1

Hoffman’s reflex (after person who discovered it)

Question 2

Roughly how much stimulation would produce a H-reflex?

Answer 2

medium

Question 3

What is a H-reflex?

Answer 3

• a test used to measure reflexes to assess health and fucntioning of nervous system
• done using an electrical stimulator
• EMG measures how long it takes and the amplitude of it

Question 4

During a H-reflex test what happens when you increase the stimulus?

Answer 4

• get an M-response and H-reflex dies down

Question 5

Why is the M-response useful?

Answer 5

• it varies very little so is the same every time for everyone
• so can use it to control and adjust stimulus you are giving
• it is basically like your ‘1 rep max’
• so you can find out how much stimulus you need to recruit all your motor units
• H/M ratio is the ratio of the size of teh H-reflex to the size of the M-response
• H/M ratio allows a quantification of the percentage of the active motoneuron pool
• this enhances the ability to compare changes in the H-reflex between subjects
• can use a stimulus that is a percentage of your ‘1 rep max’ for future testing

Question 6

True or False?
There is a point of minimal stimulus where the M-wave is absent and the H-wave is maximal.

Answer 6

True