PAER 311 WEEK 3: ELECTROTHERAPY ES TO MUSCLE CONTRACTION
NMES – NEUROMUSCULAR ELECTRICAL
STIMULATION
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Use of electrical current on MOTOR NERVES to
produce contractions on INNERVATED
MUSCLES.
Requirements: INTACT & FUNCTIONING PNS.
Can:
o Strengthen muscle
o Improve cardiovascular health
o Retard or prevent muscle atrophy
o Reduce spasticity
o Restore function
Uses: CVA, SCI, sports-related injury, post-op
conditions, healthy athelets.
Order
of
Recruitme
nt
Force
Onset
Physiologicallyinitiated
Contraction
Small Nerve
Fibers (SlowTwitch Type I ms
fibers):
x Low-Force
• Fatigueresistant
• Atrophyresistant
ElecrticallyStimulated Ms
Contraction
Largest Nerve
Fibers (FastTwitch Type II ms
fibers):
• Strongest
• Quickest
x fatigues rapidly
x disuse:
atrophies rapidly
Large
Gradually
increase
Small
Reached
Threshold: All
motor units fire
simultaneously
Rapid, Jerky
Smooth
TWO MECHANISMS TO STRENGTHEN MUSCLES
Overload Principle
Greater Load placed on a
muscle
+
Higher force of muscle
contraction
=
More muscle strength
gained
With Physio Exercise:
Load can be
progressively increased
by increasing the
RESISTANCE
Specificity Theory
Muscle contractions
specifically strengthen
the muscle fibers that
contract
Electrical stimulation has
more effect on type II
muscle fibers than on
type I muscle fibers.
With Electrical
Stimulation Connection:
Increased by:
• Increasing total
current amount
• Adjusting pulse
duration and
amplitude
• Changing
electrode size
• Increasing
externally
applied
resistance
Electrical Stimulation of Muscle Contraction
To produce STRENGTH gains in:
•
ES ms contraction: very effective in strengthening
muscle weakened by disuse
However, patients should perform both electrically
stimulated and physiological contraction, if possible,
to optimize the functional integration of strength
gains produced by stimulation
•
Healthy muscles: force of the stimulated
contraction needs to be at least 50% of the
maximum voluntary isometric contraction
(MVVIC) force
o Greatest strength gains will be achieved
with the maximally tolerated force of
contraction
After an Injury: initially have a force of as little
as 10% of MVIC
o Stronger contractions will be more
effective if they are tolerated and will
be necessary to achieve full strength.
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To optimize ENDURANCE gains
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Prolonged periods of stimulation with lowerforce contractions
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CLINICAL APPLICATION
ORTHOPEDIC CONDITIONS SURGICAL
• Applying NMES prior surgery → increased
post-operative strength & more rapid
functional improvement
• following orthopedic surgery →
immobilization + rest = Type II Fiber Atrophy
ACL Reconstruction Surgery
• Electrical stimulation can retard early decline
of isometric quads strength
TKA: Total Knee Arthroplasty
• Voluntary Exercise + NMES = improved quads
strength
ORTHOPEDIC CONDITIONS NON-SURGICAL
Knee
1. Osteoarthritis & Rheumatoid Arthritis
• Chronic inflammatory Conditions -> Type II
Muscle Fibers Atrophy
• NMES: Decreases pain, increases quads
strength, improves functional performance
(walking and stair climbing)
2. PFS: Patellofemoral Syndrome
• NMES to VVMO -> Increases VMO force
generation
Biceps
• NMES to Biceps during Resisted Elbow
Flexion = accelerated strengthening &
functional recovery
NEUROLOGICAL DISORDERS
• ES can increase strength & improve motor
control in patients c CNS damage ( SCI, CVA
& other neuro conditions ), AS LONG AS
PERIPHERAL MOTOR NERVES ARE INTACT.
• Sensory input produced by motor level
stimulation may provide cue for patient to
•
initiate movement or activate ms group 0r
may promote reflexive motor contraction.
Sensory stimulation s motor level
stimulation may also enhance brain
plasticity & cortical motor output.
Patterned sensory level stimulation, using
an intermittent stimulus, c an on:off time
but s stimulation of ms contractions may
enhance motor control by promoting
reciprocal inhibition 0f antagonist ms.
FES: Functional Electrical Stimulation
- NMES + functional activity by stimulating
contractions at the time during an
activity when ms should contract.)
SCI:
•
ES does not reverse spinal cord damage, but
reduces complications & improves quality of
life
NMES COUNTERACTS DISUSE MUSCLE ATROPHY
AND IMPROVES CIRCULATION
FES contracts muscles to assist with locomotion and
to assist with other body functions
• Criteria to be effective:
- LMN, NMJ & ms must be intact +
method of delivery must be acceptable
to pt
- Contracts ms to assist c locomotion &
other body functions
- Must produce a contraction of sufficient
force to carry out desired activity
- Must be painless
- Must be able to be controlled &
repeated
SCI:
•
FES for Ambulation
- Locomotion produced required patients
to use a walker for stability & support
- Locomotion was very slow & requires
high-level of energy expenditure by
patient
- Only practical for short distances around
home; impractical for community
mobility
NMES of Glutes → increase tissue Oxygenation &
redistribute surface pressure → reduced risk of
Pressure Ulcer
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Electrically stimulated Cycling → increases BMD
(Bone Mineral Density) by 10% - 30% → reduced risk
of Osteoporosis & associated fractures
Multiple Sclerosis (MS): ES on Peroneal Nerve during
swing phase -> Improves walking speed & decreased
energy expenditure
Implantable FES Systems
• Phrenic Nerve Stimulation → contracts
diaphragm to assist with inspiration
Abdominal & Chest Wall Stimulation →
improves coughing and clearing secretions
Sacral Nerve Stimulation → assists bowel &
bladder voiding
SPORTS MEDICINE/PERFORMANCE
Most sports require Agility, Coordination of
Agonist/Antagonist muscle Groups, Flexibility,
Proprioception & Motor Control & Balance
↓
NOT IMPROVED WITH NMES
CVA/Stroke:
a. Stimulation of weakened lower extremity
agonist muscle
= improves voluntary recruitment of motor
units, improve gait, increase Ankle DF torque,
reduce agonist-antagonist cocontraction,
increase probability of returning home.
b. NMES of Antagonist Muscle
= can reduce spasticity (by activating
reciprocal inhibition of agonist muscle),
improve strength and improve function
c. NMES to Sequentially Stimulate Agonist
followed by Antagonist Muscle
= To mimic “typical” behavior of individuals
with CNS dysfunction
= More effectively reduces spasticity
CVA/Stroke continuation
Estimulated muscle contractions can support or assist
c joint positioning or movement, functioning similarly
to an orthosis
1. Shoulder Subluxation
2. Peroneal N. Stimulation = assists DF in Swing
phase of Gait
3. Grasp
4. Stationary Cycling
Sensory Level ES = reduces spasticity, increase
strength, & increase function; enhances brain
plasticity → enhancing cortical motor output.
Other Neurological Conditions:
• ES can be used in any patients with CNS
dysfunction with an intact PNS such as
those with TBI (Traumatic Brain Injury), MS
(Multiple Sclerosis), or CP (Cerebral Palsy)
• Cerebral Palsy (CP): NMES + Dynamic
Bracing = decrease spasticity, increases
function and grip strength and improve
posture
Addition of NMES to a training program → assists in
sports that rely more heavily on strength
NMES is NOT a substitute for sport-specific training,
and it CANNOT overcome deficits in coordination,
balance, and motor control
•
For NonAthletes, incorporating NMES into
rehab program can likely improve strength,
but is NOT a substitute for a comprehensive
program of exercises that challenges
multiple systems simultaneously in a
functional manner.
OTHER CONDITIONS
a. Swallowing difficulties (dysphagia)
b. Preventing ms atrophy that occurs in astronauts
as a result of living in a ZeroGravity environment
c. Disuse Atrophy in patients confined to bed
d. Urinary Incontinence associated with Pelvic Floor
Dysfunction
e. Promote Blood Flow in Healthy Individuals and in
patients c poor circulation
f. Promoting venous circulation and preventing DVTs
EMS – ELECTRICAL MUSCLE STIMULATION
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Application of electrical currently directly to
MUSCLE to produce a ms contraction
For DENERVATED ms
o Denervation causes ms atrophy &
fibrosis → ES on ms retards or even
reverses these
A Continuous Direct Current (DC) applied for a
number of seconds to produce contractions
Electrical current must be longer than 10
milliseconds
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Precautions for the use of Electrical Currents for
Muscle Contraction
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Cardiac disease
Impaired mentation or sensation
Malignant tumors
Skin irritation or open wounds
o Be aware of potential DOMS (delated
onset muscle soreness) after electrical
stimulation
Demand pacemaker or unstable arrhythmias
Over the carotid sinus
Venous or arterial thrombosis or
thrombophlebitis
Pelvis, abdomen, trunk, and low back during
pregnancy
o Additional: Epilepsy,
Pharyngeal/Laryngeal muscle
o Don’t use ES to contract muscle if it will
disrupt healing (torn muscle, tendinitis)
PARAMETERS FOR INNERVATED MUSCLE
Electrodes
Electrode Placement:
Patient with allergic reaction to adhesive electrodes:
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One electrode: over the motor point
Other electrode: on the muscle
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Electrodes
o Must be parallel to the direction of
muscle fibers
o At least 2 inches apart
Motor Point:
- Where an electrical stimulus will
produce the greatest contraction with
the least amount of electricity
- Area of skin where motor nerve enters
the muscle
- Mostly over the middle of the muscle
belly
Electrodes
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Motor Points of the
Posterior Aspects of
Upper Extremity
MOTOR POINTS AREA
Motor points of muscle
innervated by facial
nerves
Motors points of the
anterior aspect of upper
extremity
MUSCLE
1. Frontalis
2. Corrugator
3. Orbicularis Oculi
4. Nasalis
5. Zygomaticus
6. Buccinator
7. Levators of upper lip
8. Orbicularis Oris
9. Depressor anguli oris
10. Depressor labii
infirioris
11. Mentalis
1. Middle fibers of
deltoid
2. Anterior Deltoid
3. Pectoralis Major
4. Coraco Brachalis
5. Biceps Brachii
6. Pronator Teres
7. Brachioradialis
8. Flexor Carpi Ulnaris
9. Flexor Carpi Radialis
10. Palmaris Longus
11. Flexor Digitorum
Profundus
12. Flexor Policis Longus
13. Flexor Digitorum
Superficialis
14. Abductor Policis
Longus
15. Opponencepolicis
16. Flexor Policis
17. Abductor Digiti
Minimi
Motor Points of Back
Motor Points of Muscle
on the Anterior Aspect
of the Lower Extremity
Motor Points of Muscle
on the Posterior Aspect
of the Lower Extremity
18. Flexor and
Opponence Digiti Minimi
19. Lumbricals
1. Deltoid Medial Head
2. Deltoid Posterior
Head
3. Deltoid Lateral Head
4. Triceps Long Head
5. Triceps Medial Head
6. Extensor Carpi
Radialis Longus
7. Extensor Carpi
Radialis Brevis
8. Extensor Digitorum
9. Supinator
10. Extensor Carpi
Ulnaris
11. Extensor Digiti
Minimi
12. Abductor Policis
Brevis and Extensor
Policis Brevis
13, Extensor Policis
Longus
1. Trapezius Upper
Fibers
2. Supra Spinatus
3. Rhomboidus
4. Infraspinatus
5. Teris Major and Minor
6. Latissimus Dorsi
7. Trapezius Lower
Fibers
1. Rectus Femoris
2. Vastus Lateralis
3. Vastus Medialis
4. Tibialis Anterior
5. Peroneous Longus
6. Extensor Digitonum
Brevvis
7. Peroneous Brevis
8. Extensor Hallucis
Longus
9. Extensor Digitorum
Brevis
10. Abductor Hallucis
Longus
1. Biceps Femoris
2. Semimembranous and
Semitendinosus
3. Gastrocnemius Lateral
Head
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4. Gastrocnemius Medial
Head
5. Soleus
6. Flexor Digitorum
Longus
7. Flexor Hallcis Longus
8. Tibiolis Posterior
result in greater depth of penetration than narrower
(B).
Which Color Wire Should I Use Where?
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Left Pic: Electrodes should be positioned over the
muscle tissue to be stimulated. Placement of electrodes
distal to the muscle fibers (A) results in stimulation over
areas without muscle tissue and may be uncomfortable
or result in lesser response from the muscle. Placement
over more muscular tissue (B) results in a more robust
response
Right Pic: The interelectrode distance will affect the
depth of current penetration. Wider placements (A) will
The lead wires of many electrotherapy devices
are manufactured with red & black ends. Many
clinicians assume this indicates the positive and
negative leads, respectively. However, with
currents that continually change direction,
such as AC and biphasic currents, the polarity
is continually changing, so the red and black
lead is neither the anode nor the cathode for
more than the duration of a single phase of a
biphasic pulse (i.e., microseconds). Only when
using DC, monophasic pulsed current, or
unbalanced asymmetrical pulsed current
would the red and black truly indicate an
anode and cathode.
Name
Monopolar
Electrode
Location
Active
electrode of
single circuit
over target
area; inactive
over nearby
nontreatment
area
Common Use
Pain
modulation,
iontophoresis,
tissue healing
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Bipolar
Quadripolar
Both or all
electrodes of
single circuit
over target
tissues
Four electrodes
of two circuits
over target
tissues
Muscle
activation, pain
modulation
Pain
modulation
Patient Positioning
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JOINT crossed by the stimulated ms must be in
MIDRANGE. = allows patient to perform a
strong isometric contraction
Pulse Duration
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Innervated ms: 150-350 us to stimulate motor
nerves
Smaller ms → Shorter p.d. (150-200 us) Larger
ms → Longer p.d. (200-350 us)
Small people / Children = Shorter p.d.
If SHORTENED PULSE DURATION → HIGHER
AMPLITUDE current will be required to achieve the
same strength of contraction produced by a longer
pulse duration
On:Off Time
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Selection of ideal combination of p.d. and current
amp should be based on patient’s comfort &
achievement of the desired outcome
Allows muscle to contract & relax → limits
fatigue
STRENGTHENING
o ON-time = 6 – 10 secs
o OFF-time = 50 – 120 secs
o Initial ON:OFF ratio = 1:5
o Progressed ratio = 1:4 or 1:3
RELAXATION / RELIEVE SPASM & EDEMA
muscle
o ON-time: 2-5 secs
o OFF-time: 2-5 secs
o ON:OFF ratio: 1:1
Ramp Time
Frequency:
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Determines type of response or ms contraction
As frequency increases, twitches will occur
more closely together → will produce smooth
tetanic contraction (35-50 pps)
Beyond 50-80 pps → greater muscle
strengthening → More rapid fatigue during
repeated stimulation
Recommended Frequency (clinical): 35 – 50
pps
Low Frequency: 20-30 pps better tolerated for
smaller ms (face, distal UE & all ms in young
children)
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Allows gradual increase & decrease of force
To facilitate repetitive exercise &/ or ON-time
is 6-10 secs → RAMP UP/DOWN time = 1-4 secs
Activities that require rapid contraction &
relaxation of ms, RAMP TIME SHOULD NOT BE
USED
When contraction of Antagonist to a spastic ms
is stimulated in a pt with CVA/stroke → LONG
RAMP TIME = 4-8 secs (avoids SPASTICITY)
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Current Amplitude (Intensity)
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Where the strength of contraction produced
depends the most
Ms STRENGTHENING:
o until contraction of desired strength o
o Uninjured = at least 50% of MVIC
strength
o Recovery from injury/surgery = ≥ 10%
of MVIC of uninjured limb ** stronger
contractions are likely to be more
effective
Motor ReEducation = (BEST) LOWEST Current
Amp to produce the desired fxnal mvmt **
Goal: functional mvmt that may not require
max strength ** ES can assist c functional
recovery by providing sensory input,
proprioceptive feedback of (N) motion, & inc
ms strength
Reduce Ms Spasm / Pump out Edema =
Sufficient enough to produce a visible
contraction
Treatment Time
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Parameters for NMES and FES
Muscle Strengthening = 10 – 20 contractions > 10 mins
o repeat multiple times a day if patient
has device at home done only ONCE
each visit
Motor ReEducation = at most 20 mins
o <20 mins if patient is inattentive or
fatigued
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PARAMETERS FOR DENERVATED MUSCLE
EMS Parameters Typically Used for Stimulating
Denervated Muscle
Waveform
Pulse Duration
Frequency
Amplitude
Ramp-up time
Ramp-down time
Duty cycle
Treatment time and
duration
Monophasic or DC
1-450 msec (long)
1-500 pps
To obtain contraction
but low to prevent burns
Not identified
Not indentified
Highly variable 30
minutes, 8 hours per day
5-7 days per week
4 days to 4 years
DOCUMENTATION
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Area to be treated
Patient positioning
Specific Stimulation Parameters
Electrode Placement
Tx Duration
Patient response to tx ** Include Current
Amplitude
NMES on R Biceps x 10 mins Ambulation inside //
bars: FES on R Ankle DFs during swing phase x 10:50
secs on:off time x 2 secs Ramp x 5 rounds Bells Palsy:
ES on R Facial Motor Points x 30 contractions each x 2
sets
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Doesn’t deliver current; Electrical activity
generated by ms contraction is detected
Not generally considered as an
electrotherapeutic agent
EMG Biofeedback
Criteria of use:
1.
2.
3.
4.
No visual problem
No comprehension/communication problem
Good motor control
No profound sensory loss
Contraindication:
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Any condition where ms contraction is
detrimental
Skin irritation at electrode site
ELECTROMYOGRAPHIC EMG BIOFEEDBACK
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EMG: Record of the electrical activity of
muscles using surface or fine wire/needle
electrodes •
BIOFEEDBACK: Technique of making
unconscious or involuntary body processes
perceptible to the senses to manipulate them
by conscious mental control.
Use of appropriate instrumentation to bring
covert-physiologic process to the awareness of
one or more individual
Used to transduce ms potentials into auditory
or visual cues for the purpose of increasing /
decreasing voluntary activity
Clinical Examples of Facilitatory and Inhibitory
Biofeedback
Facilitatory
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To increase muscle
activity after surgery or
injury when volitional
recruitment is impaired
To normalize the balance
of muscles acting at a
joint where one muscle
group may be insufficient
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Inhibitory
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To improve volitional
motor control following
dysfunction of the CNS
To increase volitional
control of pelvic floor
muscles for rehabilitation
of urinary incontinence
To help decrease activity
in muscle demonstrating
spasticity caused by
dysfunction of the CNS
To help decrease activity
in muscle demonstrating
increased activity caused
by postural stress or
anxiety
To help decrease muscle
activity associated with
chronic pain
EMG BIOFEEDBACK
Electrodes close together = minimize cross talk, yield
small signals, more precise signals farther apart =
yields large signal, detection from more than 1 muscle
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