Electromyography Flashcards
What is electromyography?
A way to monitor the electrical activity of muscle cells
What are the 2 ways the nervous system can increase the amount of force a muscle produces
- temporal summation
2. spatial summation
Define temporal summation
Increasing the rate at which you activate the motor units from one neuron
Define spatial summation
Increasing motor unit recruitment from other neurons
small motor units are what
small oxidative
medium motor units are what
fast oxidative glycolytic
large motor units are what
fast glycolytic
What are the two types of contraction?
Isometric and Isotonic
Define isometric
No change in muscle length but there is tension development
Define isotonic
Tension is constant while muscle length changes
What are the three types of contractions on the electromyography?
- Ramp contractions
- Maximal voluntary contractions
- Submaximal contractions
What type of contractions are the contractions found in electromyographies?
Isometric contractions
Expected results for ramp contraction
- force increases over time
- EMG amplitude increases over time
- sense of effort increases over time
Expected results for maximal voluntary contraction
- force decreased over time
- EMG amplitude decreased over time
- Sense of effort increased over time
Expected results for submaximal contractions
- force at onset and middle of the test stayed about 50% max
- force at end of test decreased
- EMG amplitude increased from onset to middle, then decreased from middle to end
- sense of effort increased over time
