Types of Electromyography Flashcards
Process of collecting data from surface electromyography
why can’t you take the Raw EMG
what does the smoothed EMG tell you
Get the raw EMG
Rectify it or turn all negative values positive
SMOOTH or average rectified EMG
the rectified or smoothed EMG relates to muscular force output
how can you use an MVC to help determine electromyography
The amplitude of the EMG signal directly corresponds to muscle force output.
Often times, we normalize the EMG to each participant’s highest amplitude obtained during a Maximal Voluntary Contraction (MVC).
Expressed as % of EMG and Force
Indwelling electromyography
why is it good?
how to make it readable
Needle gets inserted into into a target muscle and pulled out, but when it is the wire remains hooked in the muscle fibres
Can measure elec signals of small, individual muscle fibres and therefore MU
get the raw data, and decompose it which is getting rid of the noise and looking at the peaks
The spikes are single MU acting and the larger ones are FF motor units
Breaking down indwelling electromyography graphs
torque
Rectify and decompose the data
find spikes of the individual MU action potentials
MU A turns on before MU B so we know that A is a SO motor unit and B is more likely to be FR or FF
Same with torque, the highest point is FF and the lowest is SO
Effects of training on motor neurons
Effects of no training on motor neurons
why do the changes in EMG output happen with more training
- With training, we can increase the amplitude of EMG and therefore muscular force output during an MVC
- – - - -muscle force can get faster stronger and better
- during atrophy, EMG amplitude can decrease and therefore muscular force output
- Changes are thought to be due to
modulations in
CORTICAL INPUT( mind-muscle connection, control of muscle by the brain)
onto the motor neurons and changes in muscle fibre composition
- Changes are thought to be due to
