Section II NMES

Question 1

NMES

Answer 1

The application of an electrical current (usually over the motor point) to elicit a muscle contraction

Question 2

General uses of NMES

Answer 2

Muscle reeducation/strengthening
Increasing Joint ROM
Improving Function (stance/hand grip)

Question 3

Muscle Adaptations to NMES

Answer 3

Increases in Strength
increased content of muscle contractile proteins
Increases in Endurance
-increase in amount on enzymes used in aerobic pathways
-increased mitochondrial size and number
-increase capillary density

Question 4

Can electrical stimulation really help to increase muscle mass in healthy people?
Is it as effective as weight-training?

Answer 4

Not in healthy people that are 5/5 will have to increase it too much.

Question 5

Why NMES versus voluntary contraction

Answer 5

1. Reflex Inhibition
2. Selective contraction of one muscle (eg. middle deltoid, VMO)
3. Muscle reeducation
4. Compliance with HEP (home exercise program)
5. Strength less than 3+/5 (can get a stronger contraction with e-stem and build strength of contraction)
6. Form/Adjunctive of Biofeedback
7. when contracting with stim may increase total fiber recruitment

Question 6

Reflex Inhibition

Answer 6

Reflex Inhibition (RI): stimulation in which sensory stimuli impede the voluntary action of the muscle

• -Major causes of quadriceps RI are pain, joint effusion, immobilization and trauma.
• –Pain is the most commonly described cause of quadriceps RI

Question 7

Measurement methods: direct measurement via EMG, muscle biopsy, girth measurements

Answer 7

• –EMG is the most common, useful tool for investigating RI.
• –Based on EMG studies of RI, vastus medialis is most commonly affected in the quadriceps group.

Question 8

Disuse Atrophy

Answer 8

1. Refers to changes in the muscle after a period of immobilization or reduced activity.
2. Most obvious change is a decrease in crosssectional area.
3. Type I fibers affected to a greater degree

Question 9

Optimization of NMES

Answer 9

How do we get the best contraction with the greatest amount of force, while minimizing discomfort?
with the greatest amount of force, while minimizing discomfort.

Question 10

Location of Motor Point

Answer 10

1. Apply gel to skin
2. Apply electrode with firm contact to the general location of the motor point (may use 1hz)
3. With the unit on, move electrode around until a good contraction is achieved.
4. Use an indelible marking pen to draw a circle around the electrode; this allows the electrode to be placed in the same area.

Question 11

1. Optimization of NMES waveform

Answer 11

1. Waveform
   - -control is not always possible
   - -symmetrical biphasic has shown some evidence of being the most comfortable with other parameters held constant
   - -Biphasic tends to be preferred by most individuals over monophasic

Question 12

Typical Patient preference

Answer 12

Symm Biphasic (low frequency> Russian) >asym biphasic> Hi volt pulsed DC

Question 13

Russian Current

Answer 13

Compared the effects of low frequency biphasic current and “Russian” current on isometric muscular torque production of knee extensors as recorded by Biodex
Conclusions: There is no difference in the effectiveness of low frequency biphasic and Russian Currents when they are used to elicit forceful muscular contractions.

Question 14

In each burst there are

CHART!

Answer 14

there are 25 cycles(per 10 milliseconds)
Carrier frequency there are 2500 hz/2500 cycles per sec if not interrupted…because 50% it is really only 1250 hz delivered per sec.

Question 15

Compared the effects of 2500 HZ, 3750HZ, and 5000Hz on Quadriceps torque

Answer 15

Conclusions: 2500 Hz produced significantly greater torque tan 3750 or 5000Hz

Question 16

Optimization of NMES

2. pulse duration

Answer 16

2. Pulse Duration
   - -control is not always possible (may be fixed in portable NMES devices, and is fixed in HVPDC(fixed 150) and russian)
   - -Portable devices are fixed at 300-400msec
   - -100-600 usec generally used for a strong contraction while minimizing pain
   - -keep as low as possible to minimize chance of stimulating A delta’s

Question 17

3.Optimization of NMES–Frequency

Answer 17

• almost always can control this
• typically a strong, tetanic contraction can be achieved between 30-50 pps. Greater than this may cause undue fatigue
• for Russian, this means 30-50 BURSTS/second (bps)

Question 18

4.Optimization of NMES CYCLE time

Answer 18

Cycle Time
-limited choices
-for muscle strengthening 1:3-1:5 ratio (eg, 10 on 30 off)
For muscle Endurance 1:1 -1:2 ratio (eg 10 on 10 off)

Question 19

Cycle Time

Answer 19

Considerations for adjusting this:
Purpose of stimulation(endurance, strengthening, muscle re-education, etc.)
Degree of atrophy
Individual responses

Question 20

5.Ramp Optimization

Answer 20

Limited choices
sometimes built in
may or may not be built in to on/off time
increased ramp=increased comfort

Question 21

6.Electrode/Size Placement

Optimization of NEMS

Answer 21

The larger the electrode, the greater the comfort
Electrodes that are too large may stimulate unwanted muscles, too small may be painful
The closer to the motor point the greater the comfort

Question 22

When, How long

Answer 22

2X/week-daily depending upon strength of contraction

10-20 minutes common

Question 23

NMES post total Knee Aethroplasty

Answer 23

Purpose:
Examined the effect of adding high intensity NMES to a volitional strengthening program following TKA
Methods: 8 pts with bilateral TKA’s
Treatments: 3 times per week for 6 wks
2 intervention groups
1)exercise legs group –bilateral voluntary exercise programs for strengthening
2)NMES LEGS group-assignments were split
a)stronger leg at initial evaluation participated in a voluntarty exercise program
b) the weaker leg received NMES in addition to the voluntary exercise program

Question 24

TKA cont.

Answer 24

Intervention:
NMES group
10 sec, isometric contractions with 80 sec rest between contractions
-10 NMES quadriceps contractions added to each treatment session
CONCLUSION:
1. the case series does support the use of NMES to improve quadriceps strength gains following TKA surgery
2. Gains were observed during the first 3 weeks of NMES treatment that led to an increase in voluntary muscle activation
3. With the use of NMES, deficits in quadriceps strength and activation resolved quickly, and the results were maintained over a 6 moth follow-up period.
–these gains were observed in the NMES “weaker leg” group
–The “weaker leg” surpassed the strength of the contralateral “stronger” leg
4. Larger sample sizes are needed as well as the examination of carry-over quadriceps with strength gains with the use of NMES/

Question 25

NMES to improve quad strength post ACL reconstruction

Answer 25

Compared the effectiveness of using a modified NMES training program as an adjunct treatment for improving quadriceps strength and physical function in rehabilitation following ACL reconstruction --The NMES protocol used was a frequency of 25000 HZ 75burst/sec, 10 sec on and 50 sec off --Treatment was performed to elicit 10 contraction , therefore lasting 11-12minutes , 2 times a week --43 subjects who had ACLR were randomly assigned to ether a group that received (NMES group) or did not receive (comparison group) the NMES treatment along with their rehabilitation.

Question 26

ACL reconstruction cont.

Answer 26

The NMES group demonstrated greater quadriceps strength at 12 weeks (p<0.05) ---Conclusions: The modified NMES quadriceps training protocol can be useful adjunct to ACLR rehabilitation programs, but the treatment effect is smaller than what has been reported in previous studies.

Question 27

Electrodes

Answer 27

Can be cut and shaped to make smaller as long as the wire is not cut

Question 28

NMES to Increase Muscle Performance

Answer 28

1. voluntary contraction vs NMES in Normal Individuals - -80-90% of voluntary contraction possible at best 2. voluntary contraction vs. NMES in Individuals with 3+/5 or less - --NMES generally will elicit a stronger contraction

Question 29

NMES to increase ROM

Answer 29

Is stretch from NMES any better? No, but it can be combined with PROM --Patient working with NMES to increase ROM (colle's Fracture example)using a reciprocal contraction

Question 30

Pediatric Considerations

Answer 30

May take 3-5 sessions to actually get a contraction , i.e. go slowly 1st session apply electrodes, education 2nd session sensory level only (large electrodes) 3rd session-motor level but brief session (5-10 minutes) WATCH for non-verbal signs Low Frequency strengthening (<10 Hz) an option

Question 31

Geriatric Considerations

Answer 31

May have greater likelihood of decreased sensation | Watch contraindications/precautions more closely

Question 32

Reflex Inhibition

Answer 32

Prevention techniques for RI applied during the acute phase of injury in a PT setting include : ES, cold, rest - -3 major methods used to rehabilitate muscle wasting due to RI:NMES, EMG biofeedback, and traditional exercise training consisting of voluntary muscle contraction - ---NMES demonstrates advantages over other techniques in that is can override RI and cause muscle contraction, provide a level of muscle re-education, and stimulate a single component of a large muscle group.