Kinesio EMG

• number and size of MUs firing
• size/orientation of electrode
• distance from recording electrode to the MUs firing

decreases it

(impedance = resistance)

• dirty electrodes increase impedance
• skin resistance should be reduced to under 500 ohms

• rejects noise that's heard in both input leads
• (higher ratio is better)

• ratio of desired signal to background noise
• or signal power to noise power
• often expressed in decibels

draw out the electrical energy produced by the active MUs and disregards everything else

this is necessary for analyzing the info into measurable data

converts raw EMG energy/activity into half-wave or full-wave

• a form of EMG demodulation
• eliminates the neg EMG energy and only measures the pos EMG waveforms
• half the energy is eliminated

• converts neg EMG to absolute/pos values
• all EMG energy is recorded and represented with this type of rectification

a hollow mountain created above baseline when there is EMG energy (I gather that pos/neg both get represented above baseline, so it's like a hollow version of the general shape of full-wave rectification)

total amount of EMG energy as it accumulates over time is represented by a rising line that gets higher the longer you measure

EMG activity (aka MU recruitment) happens at various frequencies of firing

Frequency Analysis: determines the # of MUs firing and the frequency of firing of all MUs

During fatigue: higher freq firing MUs drop out, so the power spectrum shifts to the lower frequencies

if the envelope has shifted left it indicates fatigue - the higher freq firing MUs have dropped out

count how many times it crosses base-line?

count the spikes, both high and low

multiple spikes above baseline before crossing back down count as individual spikes

have pt do max iso on contralat limb to get a norm

common method of normalization, but not so hot bc most pts don't get max force production in most ADL, and force production in healthy pts varies by 80%

• 1) determine highest level of muscle activity for the task
• 2) compare the force actually produced with the max just measured, and show it as a percent 
• (confusing graphs on this)

get a bunch of subjects and get their average performance during various phases of a task

• comparing effort during segments of the muscle's activity
• comparing effort to that of synergistic muscles

action begins before normal onset

action continues beyond normal cessation time

EMG uninterrupted for at least 90% of gait cycle

late onset

terminates early

insufficient amplitude or duration

swing or stance timing reversed

EMG greater than normal amount

EMG value less than norm

EMG of insufficient amount to ID functional significance

long duration