ES - muscle contraction Flashcards
electrical stimulation for pain modulation
TENS
activation of skeletal muscle for neuromuscular re-education or strengthening
NMES
Activation of skeletal muscle for re-educaiton or movement training for functional use
FES
stimulation of denervated muscle
EMS
NMES purpose
- to induce contraction of skeletal muscle (with an intact peripheral nerve) to obtain similar physiological improvements that result form exercise training
NMES primarily used for
treating or preventing muscular atrophy following disuse, immobilization or detaining
primary goals of NMES
increase volitional production of muscle force when motor recruitment is most impaired
mechanisms of muscle strength gains
- neural adaptations
- muscular adaptations
neural adaptations
enchanted recruitment of motor units (number, frequency, synchronization)
muscular adaptations
- increasing contractile proteins
- changes in muscle fiber type
-altering metabolic profile
mechanisms of muscle strength loss
- intrinsic loss
- extrinsic loss
- initial strength loss post injury is usually done to extrinsic loss, but is sally surpassed by intrinsic loss
intrinsic loss
muscle atrophy and fiber loss
extrinsic loss
impaired motor unit recruitment (size, number, frequency, and synchronization)
when voluntary muscle activation may be impaired, ES results in
greater and more rapid gains in strength than voluntary exercise or no exercise at all
ES intensity and exercises intensity must be
similar to achieve similar results
the points in a muscle where there is the greatest density of motor end plates
motor point
if electrons are too small for the the targeted muscle?
increased current density may lead discomfort
why type of fibers are recruited first during voluntary contraction
type I
during NMES, which motor units are recruited first?
Type II
ES result in early ____ compared with voluntary recruitment
early fatigue
since no peripheral nerve with motor endplate, the sarcolemma must be depolarized around the. muscle cell itself
EMS
Typically biphasic current - functional tasks
FES
Electrical muscle stimulation (EMS)
- maintains contractile properties of the muscle while awaiting reinnervation
- used in patients with peripheral nerve injuries
- atrophy and fibrosis can be attenuated
- literature is controversial
ems activation of the muscle requires depolarization of the muscle membrane itself
the sarcolemma
functional electrical stimulation (FES)
- primary goal is to improve function, not increase strength as in NMES
FES intensity is only enough to
meet the demands of the specific functional task
evidence for the use of NMES
-improved strength gains without hypertrophy
- hypertrophy with CNS lesion
- hypertrophy with MSK disorders
-improvements in hypertrophy
High volt pulsed current (HVPC)
- twin peaked monophonic pulsed current
- peak voltage 150 to 500 v
- short pulse duration (50 to 100usec)
- frequency of 1 to 120Hz
HVPC is for
preventing or reducing edema
HVPC parameters
- current type: monophonic
- frequency 100 -125 ops
- pulse duration 2-100usec
- amplitude: comfortable sensory perception (10%)
- time: 20 min intervals or several hours
NMES parameters for reducing edema
- current type: biphasic PC or Russian/Aussie
- Frequency: 20-80pps
- pulse duration:100-600usec if PC
- amplitude: visible contraction
- time: 10-20 min treatment sessions 3sec on; 3sec off
