Electromyography Flashcards
Amplifier
Device that electrodes send signals to to records the difference between two signals
Analog-to-Digital converter
Converts analog signals to digital signals
Bipolar
Two electrodes placed over the muscle
Electrode
Conductor where electricity enters or leaves an object, substance, or region
Electromechanical delay
Delay between the electrical activity in the muscle and the force development by the muscle
Electromyography
The study of electrical signals in muscles, electrical activity from all active muscle fibres below the electrodes
Extrinsic
Factors outside of the muscle
Full wave rectification
Take the peak-to-peak value of the signal
Indwelling electrode
Needles inserted into muscle
Innervation ratio
Number of muscle fibres in a motor unit
Intrinsic
Factors within the muscle
Isometric
Tension developed without contraction of the muscle
Isotonic
Tension remains unchanged and muscle length changes
Large motor unit
Thousands of muscle fibres, little control, increased muscle strength (leg muscles)
Linear envelope
Looking at the average trend of the EMG data
Motor unit
One motor neurone connects to many muscle fibers
Muscle action potential
Electrical signals in the muscle (analog signal)
Reference electrode
Electrode placed on bony prominence
Sampling frequency
Number of samples taken per unit time during muscle event
Small motor unit
A few muscle fibers in unit, not very strong, provide a lot of control (eye muscles)
Somatic motor unit
Nerve cells that run from spinal cord to muscle
Surface electrode
Stickers placed on the skin
