Electrical Simulation for Muscle Contraction

indications

_______ for electrical stimulation for muscle contraction include to prevent muscle atrophy following disuse, immobilization, detraining, increasing/decreasing ROM, muscle reeducation/inhibition, and facilitating muscle for movement or posture

action potential

adequate nerve stimulation is needed to stimulate an ____ _____

subthreshold

stimulus is inadequate for stimulation

threshold

stimulus is just adequate for stimulation

suprathreshold

stimuli exceeding the minimal strength and duration needed for stimulation

rapid intensity duration

criteria for adequate stimulation include; must be sufficiently _____ rate of change, must be adequate stimulus ______ (depolarize cell membrane), and must have adequate _____

accommodation

having a sufficiently rapid rate of change prevents ________

longer

denervated muscle requires _____ duration current than normal muscle

lower

larger diameter axons have a _____ threshold and are more easily stimulated

decrease

as duration increases, intensity must _____

neuromuscular electrical stimulation (NMES)

use of electrical currents to produce muscle contractions in INNERVATED muscles

peripheral

NMES requires an intact and functioning ______ nervous system

NMES

______ can be used with patients with stroke, spinal cord injury, and post-op

strength duration

depolarization of a muscle requires an electrical stimulus with sufficient _____ and _____

diameter resistance

clinical electrical stimulation usually involves the stimulation of peripheral nerves; the nerve fibers with the greatest _____ and lowest ______ depolarize first

A alpha

____-____ fibers are first to be depolarized (carry motor and proprioceptive input)

closest

muscle fibers ______ to electrode will stimulate first

2 1

electrically stimulated muscle contractions stimulate fast twitch type _____ muscle fibers first, whereas physiological muscle contractions stimulation slow twitch type ____ muscle fibers first

strong quick quickly rapidly

electrically stimulated muscle contractions produce ____ and ____ contracts that fatigue _____, and atrohpy _____ui

synchronous asynchronous

electrically stimulated contractions have recruitment that is _____, and physiologically stimulated contractions have recruitment that is ______

overload principle

increased pulse duration, amplitude, electrode size, external resistance --> higher load ---> higher force contraction ---> greater therapeutic effect

specificity

ES has more effect on type 2 muscle fibers than on type 1 muscle fibers; disuse atrophy is primarily of type 2 fibers

quadriceps inhibition (arthrogenic inhibition)

decreased motor recruitment and decreased force output gain (action potential for quadriceps contraction is more difficult to reach)

reeducation

one major use for electrical stimulation for muscle contraction is increasing muscle ______ after surgery (quadriceps contractions post knee surgery)

pain contraction functional

electrical stimulation for muscle contraction can also be used for nonsurgical management of knee conditions; for example, decreasing ____, increasing quality of _____, and improve _____ performance

functional electrical stimulation (FES)

electrical stimulation integrated with performance of functional activities; ex - stimulating the anterior tibialis during the swing phase of gait to initiate ankle DF to allow for foot clearance

10

ESTIM for denervated muscles requires pulse duration of > _____ms

continuous direct

ESTIM for denervated muscle uses ________ and ______ current

not

improvements do ____ persist after stimulation has stopped when using estim for denervated muscles

recruitment rate coding

to achieve high force you can activate more motor units (________) or drive the motor units more quickly (_____ _____)

amplitude pulse duration

to increase recruitment of motor units, you can increase _____ or increase _____ _____; can increase both but must be careful of fatigue

high

_______-intensity NMES is necessary to recover force production with muscle contraction in innervated muscles

50

intensity of NMES must be > _____% max voluntary isometric contraction

1000 2500 2 10 50

with Russian protocol, there is ______ or ______ Hz alternating current that is interrupted and delivered in short bursts --> 50 burts per second, on ____-____ sec, off ____sec

motor parallel

when placing electrodes, one should be placed over _____ unit, and the other electrode should be over stimulated muscle aligned ______ to muscle fiber direction

2

electrodes should be placed at least ____ inches apart and the bigger the electrodes the better

midrange isometric

during Estim, joint should be kept in _____ with _____ or isotonic contraciton

50 maximum

amplitude: contraction > ____% maximum volitional contraction and best results occur when performed at the ______ intensity the patient can tolerate

150 400 400

pulse duration: _____-____ µs or > ______ µs for quadriceps rehab

shorter longer

______ pulse durations are required for smaller muscles while _____ pulse durations are required for larger muscles

20 30 35 50 50 75

Frequency: ____-___pps for small muscles (fascial, hand, foot), ____-____ pps for larger muscles, ____-____pps may increase muscle strengthening but also increase fatique - should be used with QUAD REHAB

6 12 50 120

On/Off times: muscle strengthening = on ____-____ seconds, off ___-____ seconds (1:5 ratio)

1 4

ramp up/ramp down time: ____-____ seconds

1 1

relieve muscle spasms and edema = ratio of ___:___ with on and off times of 2-5 seconds

15

for muscle re-education, treatment time should be roughly _____ minutes, allowing for 10-20 contractions. No longer than 20 minutes in a single session unless specific reason