(S1W3) Electromyography (EMG) part 7

Question 1

What happens if you repeat Dewhurst’s experiment but allow your arm to fall?

Answer 1

• M1 (stretch reflex) will still happen the same
• M2 will either not happen or to a much lesser degree
• M3 will not happen because you are allowing your arm to fall

Question 2

limitations of sEMG

Answer 2

• other components included in signal (noise, intracellular action potentials that aren’t related to muscle contraction)
• excitation is not equal to activation
• not measuring muscle force

Question 3

Why is excitation not equal to activation?

Answer 3

neuromechanical delays
* propagation of action potentials
* ion kinetics (movement of ions) - time for soidum to enter neuron, time to diffuse and trigger action potential, time taken for calcium to be released
* small degree of randomness in how much diffusion, how many things actually bind to what
* slight temporal delay from when excitation happens to muscle activation